Method for producing epichlorohydrin

Abstract

A method for producing epichlorohydrin. The method comprises the following steps: A1, in the presence of a catalyst and a solvent, bringing 3-chloropropene and an aqueous hydrogen peroxide solution into contact to perform a reaction, so as to obtain a mixture containing epichlorohydrin and a waste liquid containing hydrogen peroxide; and A2, in a hydrogen atmosphere, subjecting the waste liquid containing hydrogen peroxide and a hydrogenation catalyst to a catalytic hydrogenation reaction, wherein the catalyst used in step A1 is a titanium silicalite molecular sieve catalyst, and the catalyst comprises a titanium silicalite molecular sieve and an inorganic oxide. On the basis of the total mass of the catalyst, the content of the titanium silicalite molecular sieve is 70-95 wt%, and the content of the inorganic oxide is 5-30 wt%. The side-pressure crushing strength of the catalyst is 60-150 N / cm; and / or the hydrogenation catalyst used in step A2 comprises an activated carbon carrier and an active metal component, with the active metal component comprising Pd.

Description

A method for producing epichlorohydrin Technical Field

[0001] This invention relates to the field of epichlorohydrin production, specifically to a method for producing epichlorohydrin via the epoxidation reaction of 3-chloropropene using a titanium silicate molecular sieve catalyst. Background Technology

[0002] Epichlorohydrin is a widely used basic organic chemical raw material. Using hydrogen peroxide as an oxidant in a mixed solution of methanol and water, and with titanium silicate molecular sieves as a catalyst, 3-chloropropene can be directly epoxidized to epichlorohydrin. This is a new generation of green production technology for epichlorohydrin, offering advantages such as clean process, high production efficiency, and low carbon footprint.

[0003] Titanium silicate molecular sieves are a key catalytic material in the hydrogen peroxide-based green production technology of epichlorohydrin. To adapt to the industrialization of this technology, the molding method of titanium silicate molecular sieve catalysts has received widespread attention.

[0004] To address the challenge of separating the titanium silicate molecular sieve catalyst powder from the liquid products, a method for preparing TS-1 microspheres with an average diameter of approximately 20 μm using spray molding has been proposed. However, this method requires filtration to separate the microsphere catalyst from the reaction products of 3-chloropropene and hydrogen peroxide epoxidation, limiting the application of this catalyst in fixed-bed reactors and similar applications.

[0005] A method for preparing extruded titanium-silicon molecular sieve catalysts and their application in the epoxidation reaction of 3-chloropropene and hydrogen peroxide has been proposed. The preparation method involves mixing TS-1 titanium-silicon molecular sieve, polymethylsiloxane as a binder, methylcellulose as a plasticizer, melamine as a pore-forming agent, and water as a paste-forming agent to form a paste. This paste is then extruded using an extruder to obtain strip-shaped catalysts. After drying and calcining, the strip-shaped catalysts are obtained. The epoxidation reaction of 3-chloropropene and hydrogen peroxide is carried out in a fixed-bed circulating reactor, but the conversion rate of hydrogen peroxide is only 89%.

[0006] A method for preparing extruded titanium-silicon molecular sieve catalysts and their application in the epoxidation reaction of 3-chloropropene with hydrogen peroxide has been proposed. TS-1 titanium-silicon molecular sieves, nano-alumina, alumina sol, pore-forming agents, extrusion aids, and water are mixed to obtain a formable material. This material is then extruded using an extruder to obtain wet strip-shaped pieces. The extruded strip-shaped pieces are dried and calcined to obtain the shaped catalyst. The epoxidation reaction of 3-chloropropene with hydrogen peroxide is carried out in a fixed-bed reactor, achieving a hydrogen peroxide conversion rate of 99.2% and an epichlorohydrin selectivity of 96.9%. However, the mechanical strength of the catalyst is only 20-30 N / cm². 2This makes it difficult to meet the requirements of industrial fixed-bed reactors.

[0007] A method for preparing high-strength extruded titanium-silicon molecular sieve catalysts and their application in the epoxidation reaction of 3-chloropropene and hydrogen peroxide has been proposed. TS-1 titanium-silicon molecular sieve, aluminum hydroxide powder, aluminum sol, pore-forming agent, extrusion aid, and water are mixed to obtain a formable material. This material is then extruded using an extruder to obtain a wet strip-shaped body. The extruded strip-shaped body is dried and calcined to obtain the shaped catalyst. The lateral crushing strength of the shaped catalyst is 70-150 N / cm. However, the main active component, titanium-silicon molecular sieve, has a content of 40-65% by mass, which is relatively low, limiting the catalyst's catalytic performance. Furthermore, the combined content of the pore-forming agent and extrusion aid accounts for 30-70% of the titanium-silicon molecular sieve mass, which is excessive. This increases the requirements for drying and calcining the wet strip-shaped body, increasing the energy consumption and cost of catalyst preparation.

[0008] Therefore, obtaining high-strength, high-catalytic-performance, and high-economic-performance titanium-silicon molecular sieves suitable for fixed-bed reactors is the first technical problem that urgently needs to be solved in the process of direct epoxidation of 3-chloropropene to produce epichlorohydrin.

[0009] The method for producing epichlorohydrin via the epoxidation reaction of 3-chloropropene and hydrogen peroxide can achieve a continuous and stable synthesis of epichlorohydrin, with a hydrogen peroxide conversion rate of not less than 97%. However, hydrogen peroxide is not completely converted during the reaction, and a small amount of unconverted hydrogen peroxide remains in the final epoxidation wastewater, with a mass fraction of approximately 0.05-0.5% (500-5000 ppm). This residual trace amount of hydrogen peroxide may react with methanol, affecting the safe and continuous operation of the plant, and requires treatment to avoid adverse effects.

[0010] Some have proposed using hydrogen peroxide decomposition catalysts (such as metal oxides) to catalytically decompose this portion of hydrogen peroxide. However, the oxygen produced may pose a safety risk to the reaction device, requiring nitrogen to be used for dilution and discharge, consuming a large amount of nitrogen and increasing production costs.

[0011] Therefore, in the process of direct epoxidation of 3-chloropropene to produce epichlorohydrin, in order to improve the safety and economy of the reaction process, the second technical problem that urgently needs to be solved is to develop a new generation of technology for treating unreacted trace amounts of hydrogen peroxide in epoxidation wastewater.

[0012] Epichlorohydrin is primarily synthesized using 3-chloropropene as a raw material. During the production of 3-chloropropene, various chlorohydrocarbon byproducts are generated. Among them, 1-chloropropane, a byproduct with a boiling point highly similar to 3-chloropropene, significantly reduces the purity of 3-chloropropene, potentially leading to a series of adverse effects on subsequent epichlorohydrin production. In currently reported conventional processes for producing epichlorohydrin via the epoxidation reaction of 3-chloropropene and hydrogen peroxide, 3-chloropropene is in excess relative to hydrogen peroxide and needs to be recycled. However, the 1-chloropropane impurity in 3-chloropropene does not participate in the reaction and will accumulate continuously during the 3-chloropropene recycling process. It is necessary to periodically discharge 3-chloropropene containing high concentrations of 1-chloropropane to control the continuous increase in the concentration of 1-chloropropane in the reactor. This undoubtedly represents a huge waste of resources and also increases production costs and environmental burden. Therefore, effectively separating 3-chloropropene and 1-chloropropane from epichlorohydrin and reusing the separated 3-chloropropene containing 1-chloropropane is of great significance for epichlorohydrin production.

[0013] A method for separating epichlorohydrin has been proposed, which includes a first atmospheric distillation of an epichlorohydrin solution containing 3-chloropropene to obtain a first top product with a 3-chloropropene content of not less than 99% by weight, and a first bottom product containing epichlorohydrin. However, because the boiling points of 1-chloropropane and 3-chloropropene are very close (difference within 2°C), it is difficult to achieve complete separation of 3-chloropropene and 1-chloropropane using conventional atmospheric distillation methods.

[0014] One proposed method involves the adsorption and separation of a mixture of 3-chloropropene and 1-chloropropane gases. This method involves contacting an ultraporous metal-organic framework (MOF) material with the mixture to adsorb the 1-chloropropane, thus achieving the adsorption and separation of the 3-chloropropene and 1-chloropropane mixture. However, this method requires specialized ultraporous MOF materials and vacuum activation, resulting in high costs.

[0015] One proposed method for purifying 3-chloropropene involves the gas-phase dehydrochlorination of 1-chloropropane to produce propylene, thereby purifying 3-chloropropene. This method uses chemical conversion to transform 1-chloropropane into propylene, which has a lower boiling point, thus achieving the goal of purifying 3-chloropropene. However, propylene has a low added value, resulting in low overall economic efficiency for this method.

[0016] Therefore, in the process of direct epoxidation of 3-chloropropene to produce epichlorohydrin, providing a simple and green method for separating 3-chloropropene and 1-chloropropane in epichlorohydrin is the third technical problem that urgently needs to be solved. Summary of the Invention

[0017] To address the three technical problems mentioned above, this invention provides technical solutions to solve the corresponding technical problems, and ultimately provides a method for producing epichlorohydrin through the epoxidation reaction of 3-chloropropene.

[0018] In a first aspect of the invention, addressing the aforementioned first technical problem, the present invention provides a titanium-silicon molecular sieve catalyst and its preparation method, and applies this titanium-silicon molecular sieve catalyst to the process of preparing epichlorohydrin via the epoxidation reaction of 3-chloropropene. The catalyst provided by the present invention possesses both high strength and high catalytic performance, making it suitable for olefin epoxidation reactions.

[0019] Specifically, the present invention provides a titanium-silicon molecular sieve catalyst, the catalyst comprising titanium-silicon molecular sieve and alumina, wherein, based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt% and the content of alumina is 5-30 wt%; wherein, the lateral crushing strength of the catalyst is 60-120 N / cm.

[0020] The present invention also provides a method for preparing a titanium-silicon molecular sieve catalyst, the method comprising the following steps: mixing and molding a titanium-silicon molecular sieve precursor containing a template agent, an alumina precursor and an extrusion aid, and then drying and calcining the mixture;

[0021] The mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor.

[0022] The present invention also provides the application of the above-mentioned titanium-silicon molecular sieve catalyst or the titanium-silicon molecular sieve catalyst prepared by the above preparation method in the olefin epoxidation reaction.

[0023] The present invention also provides a method for preparing epichlorohydrin by epoxidation of 3-chloropropene, the method comprising: reacting 3-chloropropene and an aqueous solution of hydrogen peroxide in the presence of a catalyst and a solvent; wherein the catalyst is the above-mentioned titanium-silicon molecular sieve catalyst or the titanium-silicon molecular sieve catalyst prepared by the above preparation method.

[0024] The titanium-silicon molecular sieve catalyst provided by this invention, while possessing good mechanical strength, increases the content of the main active component, titanium-silicon molecular sieve, thereby further improving the catalyst's catalytic performance and stability. It not only meets the application requirements of industrial fixed-bed reactors and other similar applications, achieving automatic separation of the catalyst and reaction products, but also significantly improves the catalyst's catalytic effect and lifespan. The catalyst provided by this invention is suitable for catalyzing the epoxidation reaction of olefins, particularly in the epoxidation of 3-chloropropene to epichlorohydrin, where it maintains high catalytic activity and epichlorohydrin selectivity for a longer period.

[0025] The catalyst preparation method provided by this invention innovatively uses titanium-silicon molecular sieve precursors with template agents still attached as one of the main raw materials, effectively utilizing the pore-forming function of the template agent during the calcination process, avoiding the use of a large amount of organic pore-forming agents and extrusion aids. This not only simplifies the overall catalyst preparation process, but also saves the large amount of energy consumed in the calcination step of removing the template agent during the production of titanium-silicon molecular sieve raw powder, and reduces the energy consumption of calcining to remove pore-forming agents and extrusion aids during the titanium-silicon molecular sieve forming process, thus significantly reducing the overall production cost of the catalyst.

[0026] In a second aspect of the invention, addressing the second technical problem mentioned above, the invention proposes a method for removing hydrogen peroxide from epichlorohydrin wastewater (i.e., the waste liquid obtained after removing unreacted reactants and the target product formed after the epoxidation synthesis reaction, specifically the waste liquid obtained after removing unreacted 3-chloropropene and the target product epichlorohydrin after the epoxidation synthesis of epichlorohydrin from 3-chloropropene). This method can convert the residual small amount of hydrogen peroxide into water, avoid the generation of oxygen, significantly reduce nitrogen consumption, and improve the technical economy and safety of the reaction process.

[0027] Specifically, the present invention provides a method for removing hydrogen peroxide from epichlorohydrin wastewater, comprising the following steps:

[0028] In a hydrogen atmosphere, epichlorohydrin wastewater is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to convert hydrogen peroxide in the epichlorohydrin wastewater into water; wherein the hydrogenation catalyst comprises an activated carbon support and an active metal component; the active metal component comprises Pd.

[0029] Optionally, based on the total weight of the hydrogenation catalyst, the content of the active metal component is 0.1-13% by weight, preferably 0.5-1% by weight.

[0030] Optionally, the total specific surface area of ​​the hydrogenation catalyst is 1100-2000 m². 2 / g, preferably 1500-2000m 2 / g; particle size is 10-180 mesh, preferably 20-110 mesh;

[0031] Optionally, the microporous specific surface area of ​​the hydrogenation catalyst accounts for 90-100% of the total specific surface area.

[0032] Optionally, the hydrogenation catalyst is prepared by a method comprising the following steps:

[0033] (1) The activated carbon support is impregnated with an active metal precursor solution and then dried to obtain a catalyst precursor; optionally, the active metal precursor is selected from one or more of palladium acetate, palladium nitrate, palladium chloride and palladium oxalate, preferably palladium chloride.

[0034] (2) The catalyst precursor is calcined and reduced under hydrogen conditions.

[0035] Optionally, in step (1), the concentration of palladium ions in the active metal precursor solution is 0.05-7% by weight, preferably 0.25-0.50% by weight. Preferably, the impregnation treatment is equal volume impregnation; the impregnation temperature is 20-30℃, and the impregnation time is 10-15h.

[0036] Optionally, the drying conditions include: a drying temperature of 100-120℃ and a drying time of 6-10h;

[0037] Optionally, in step (2), the conditions for the calcination reduction treatment include: a reduction temperature of 300-750℃, preferably 300-620℃; a reduction time of 2-8h, preferably 3-6h; and a hydrogen flow rate of 5-100mL / min, preferably 5-60mL / min.

[0038] Optionally, the epichlorohydrin wastewater originates from the reaction of 3-chloropropene with hydrogen peroxide to synthesize epichlorohydrin;

[0039] Optionally, based on the total weight of the epichlorohydrin wastewater, the hydrogen peroxide content is 0.05-3% by weight, preferably 0.1-0.5% by weight.

[0040] Optionally, the epichlorohydrin wastewater further includes methanol and water; based on the total weight of the epichlorohydrin wastewater, the methanol content is 20-80% by weight, preferably 40-60% by weight.

[0041] Optionally, in the catalytic hydrogenation reaction, the weight ratio of epichlorohydrin wastewater to hydrogenation catalyst is 100:0.1-7, preferably 100:0.1-1.5.

[0042] Optionally, the conditions for the catalytic hydrogenation reaction include: a reaction temperature of 20-50°C, a reaction time of 10-60 min, and a hydrogen pressure of 1-10 bar.

[0043] Optionally, the conditions for the catalytic hydrogenation reaction include: a reaction temperature of 25-45°C, a reaction time of 20-60 min, and a hydrogen pressure of 2-10 bar.

[0044] The method for removing hydrogen peroxide from epichlorohydrin wastewater according to the present invention uses a hydrogenation catalyst with metal Pd as the active center and activated carbon as the support. This catalyst exhibits excellent catalytic activity for the hydrogenation of hydrogen peroxide to water, avoids oxygen generation, significantly reduces nitrogen consumption, and improves the technical economy and safety of the reaction process.

[0045] In a third aspect of the invention, addressing the third technical problem mentioned above, the present invention provides a method for separating 3-chloropropene and 1-chloropropane, and a method for producing epichlorohydrin. The method described in this invention can efficiently separate 1-chloropropane and 3-chloropropene, thereby helping to reduce the energy and material consumption of the equipment.

[0046] Specifically, the present invention provides a method for separating 3-chloropropene and 1-chloropropane, comprising the following steps:

[0047] (1) A mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is subjected to a first distillation separation in a first distillation column to obtain a top product containing 3-chloropropene and 1-chloropropane and a bottom product containing epichlorohydrin; wherein, in the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1;

[0048] (2) Under the action of a catalyst, the top product obtained in step (1) is reacted with hydrogen peroxide; wherein the molar ratio of 3-chloropropene to hydrogen peroxide in the top product is 0.7-0.99:1.

[0049] (3) The reaction product obtained in step (2) is subjected to a second distillation in a second distillation column to obtain a top product rich in 1-chloropropane and a bottom product rich in epichlorohydrin; wherein the mass fraction of 1-chloropropane in the top product is not less than 10% and the mass fraction of 1-chloropropane in the bottom product is not more than 0.1%.

[0050] The present invention also provides a method for producing epichlorohydrin, comprising the following steps:

[0051] S1. In methanol solvent, 3-chloropropene containing 1-chloropropane and hydrogen peroxide are subjected to an epoxidation reaction to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide.

[0052] S2. The solution containing epichlorohydrin, 3-chloropropene, 1-chloropropene, methanol, water and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropene and epichlorohydrin and a solution containing methanol, water and hydrogen peroxide.

[0053] S3. Separate 3-chloropropene and 1-chloropropane from the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the method for separating 3-chloropropene and 1-chloropropane is the same as the method described above for separating 3-chloropropene and 1-chloropropane.

[0054] S4. In a hydrogen atmosphere, the solution containing methanol, water and hydrogen peroxide obtained in S2 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing methanol and water; then, optionally, the solution containing methanol and water is subjected to distillation to obtain methanol.

[0055] In existing conventional processes for producing epichlorohydrin via the epoxidation reaction of 3-chloropropene and hydrogen peroxide, previous literature reports indicate that 3-chloropropene needs to be in excess relative to hydrogen peroxide to achieve high catalyst activity and epichlorohydrin selectivity. This necessitates the recycling of excess 3-chloropropene. However, the 1-chloropropane impurity in 3-chloropropene does not participate in the reaction and accumulates continuously during the 3-chloropropene recycling process. Therefore, 3-chloropropene containing high concentrations of 1-chloropropene must be periodically discharged to control the continuous increase in the 1-chloropropane concentration in the reactor. This represents a significant waste of resources and also increases production costs and environmental burden.

[0056] Based on this, the present invention provides a novel method for reusing the portion of 3-chloropropene containing a high concentration of 1-chloropropane that is periodically discharged, avoiding resource waste and reducing production costs and environmental burden. The present invention first separates the lower-boiling-point 3-chloropropene and 1-chloropropane components from the higher-boiling-point epichlorohydrin through distillation. Second, taking advantage of the chemical inertness of 1-chloropropane in epoxidation reactions, the 3-chloropropene containing 1-chloropropane undergoes an epoxidation reaction with excess hydrogen peroxide in the presence of a catalyst, converting 3-chloropropene into epichlorohydrin, which has a higher boiling point and greater economic value, as much as possible. Finally, the low-boiling-point 1-chloropropane that does not participate in the reaction is separated by atmospheric distillation. This process effectively separates 1-chloropropane from 3-chloropropene, converting 3-chloropropene into epichlorohydrin, which has higher economic value. It is significant for reducing material and energy consumption in the hydrogen peroxide-based epichlorohydrin production process, reducing 3-chloropropene material consumption by more than 5%. This method is characterized by its simplicity, ease of implementation, economic efficiency, and environmental friendliness.

[0057] The present invention also provides a method for producing epichlorohydrin, comprising the following steps:

[0058] A1. In the presence of a catalyst and a solvent, 3-chloropropene and an aqueous solution of hydrogen peroxide are reacted to obtain a mixture containing epichlorohydrin and a waste liquid containing hydrogen peroxide.

[0059] A2. In a hydrogen atmosphere, waste liquid containing hydrogen peroxide is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst.

[0060] The catalyst in step A1 is optionally, but preferably, the titanium-silicon molecular sieve catalyst described in the first aspect above.

[0061] The hydrogenation catalyst in step A2 is the hydrogenation catalyst described in the second aspect above.

[0062] Preferably, step A1 is performed according to the technical solution in the first aspect described above, and step A3 is performed according to the technical solution in the second aspect described above.

[0063] Specifically, in the above-described method for producing epichlorohydrin, step A1 includes epoxidizing 3-chloropropene containing 1-chloropropane and hydrogen peroxide in a methanol solvent in the presence of a catalyst (or epoxidation catalyst) to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water, and hydrogen peroxide; the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water, and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, and a waste liquid containing methanol, water, and hydrogen peroxide;

[0064] Step A2 includes catalytically hydrogenating the waste liquid containing methanol, water, and hydrogen peroxide obtained in step A1 with a hydrogenation catalyst in a hydrogen atmosphere to obtain a solution containing methanol and water; then optionally, the solution containing methanol and water is distilled to obtain methanol.

[0065] The method further includes step A3, wherein the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is separated, the separation method comprising:

[0066] (1) A mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is subjected to a first distillation separation in a first distillation column to obtain a top product containing 3-chloropropene and 1-chloropropane and a bottom product containing epichlorohydrin; wherein, in the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1;

[0067] (2) Under the action of a catalyst, the top product obtained in step (1) is reacted with hydrogen peroxide; wherein the molar ratio of 3-chloropropene to hydrogen peroxide in the top product is 0.7-0.99:1.

[0068] (3) The reaction product obtained in step (2) is subjected to a second distillation in a second distillation column to obtain a top product rich in 1-chloropropane and a bottom product rich in epichlorohydrin; wherein the mass fraction of 1-chloropropane in the top product is not less than 10% and the mass fraction of 1-chloropropane in the bottom product is not more than 0.1%. Detailed Implementation

[0069] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0070] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0071] In a first aspect, the present invention provides titanium-silicon molecular sieve catalysts, their preparation methods and applications, and a method for preparing epichlorohydrin by epoxidation of 3-chloropropene.

[0072] Specifically, the present invention provides a titanium-silicon molecular sieve catalyst, the catalyst comprising titanium-silicon molecular sieve and alumina, wherein, based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt% and the content of alumina is 5-30 wt%.

[0073] The side crushing strength of the catalyst is 60-120 N / cm.

[0074] According to the present invention, based on the total mass of the catalyst, the content of titanium silicate molecular sieve is 70-95 wt%, specifically 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, and any two of these values, preferably 70-90 wt%; the content of alumina is 5-30 wt%, specifically 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, and any two of these values, preferably 10-30 wt%. Using this preferred embodiment, the increased content of the active component in the catalyst is beneficial for improving the catalytic activity of the catalyst.

[0075] Preferably, the sum of the content of titanium silicate molecular sieve and the content of alumina is ≥98wt%, or ≥99wt%, or ≥99.5wt%, or ≥99.9wt%, or 98-100wt%, or 98-99.99wt%, or 99.9-99.99wt%.

[0076] The catalyst described in this invention has high mechanical strength, which can extend the catalyst's lifespan and is more conducive to the long-term operation of the device. According to this invention, the lateral crushing strength of the catalyst is 60-120 N / cm, specifically 60 N / cm, 65 N / cm, 70 N / cm, 75 N / cm, 80 N / cm, 85 N / cm, 90 N / cm, 95 N / cm, 100 N / cm, 105 N / cm, 110 N / cm, 115 N / cm, 120 N / cm, and any two of these values ​​forming a range, preferably 60-100 N / cm, more preferably 70-90 N / cm, and most preferably 85-90 N / cm.

[0077] According to the present invention, preferably, in the titanium-silicon molecular sieve, the mass fraction of titanium, calculated as TiO2, is 1-10%, specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and any two of these values, preferably 1-5%.

[0078] According to the present invention, preferably, the titanium-silicon molecular sieve is selected from at least one of titanium-silicon molecular sieves having MFI structure, MEL structure, BEA structure, MSE structure and MWW structure, and more preferably selected from at least one of TS-1 molecular sieve, TS-2 molecular sieve, Ti-Beta molecular sieve, Ti-MCM-68 molecular sieve and Ti-MWW molecular sieve.

[0079] More preferably, the titanium-silicon molecular sieve is selected from titanium-silicon molecular sieves with an MFI structure, preferably TS-1 molecular sieve.

[0080] The present invention also provides a method for preparing a titanium-silicon molecular sieve catalyst, the method comprising: mixing and molding a titanium-silicon molecular sieve precursor containing a template agent, an alumina precursor and an extrusion aid, and then drying and calcining the mixture;

[0081] The mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor.

[0082] According to the present invention, preferably, in the titanium-silicon molecular sieve precursor, the mass fraction of titanium, based on the dry basis mass of the titanium-silicon molecular sieve precursor and calculated as TiO2, is 1-10%, preferably 1-5%.

[0083] According to the present invention, preferably, the content of the template agent in the titanium-silicon molecular sieve precursor is 1-20 wt%, more preferably 1-10 wt%.

[0084] The present invention allows for a wide range of choices for the template agent, which can be conventional choices in the art. Preferably, the template agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0085] The present invention does not particularly limit the source of the titanium-silicon molecular sieve precursor containing the template agent. It can be carried out by referring to conventional methods in the art, or it can be obtained commercially. The present invention does not particularly limit this.

[0086] In this invention, the template-containing titanium-silicon molecular sieve precursor refers to the product obtained at any stage after hydrothermal crystallization and before calcination during the synthesis of titanium-silicon molecular sieves using a template agent via hydrothermal crystallization. During the synthesis of titanium-silicon molecular sieves, drying and calcination are typically performed after hydrothermal crystallization. The upper limit of the drying temperature is typically 200°C, while the calcination temperature is higher than the drying temperature. Preferably, the template-containing titanium-silicon molecular sieve precursor refers to the product obtained after hydrothermal crystallization and drying, but before calcination, during the synthesis of titanium-silicon molecular sieves using a template agent via hydrothermal crystallization. This invention does not particularly limit the hydrothermal crystallization process; any hydrothermal crystallization process known in the art for the synthesis of titanium-silicon molecular sieves is applicable.

[0087] Preferably, the preparation method of the titanium-silicon molecular sieve precursor containing the template agent includes: mixing a titanium source, a silicon source, a template agent and water, performing hydrothermal crystallization, and then drying.

[0088] The present invention does not impose any particular limitations on the specific conditions in the above preparation process, and can refer to conventional methods in the field.

[0089] Preferably, the molar ratio of silicon source, titanium source, template agent and water is 100:(0.05-8):(0.5-30):(500-5000).

[0090] Preferably, the conditions for hydrothermal crystallization include: a temperature of 100-180℃ and a time of 1-20h.

[0091] According to the present invention, preferably, the method for preparing the titanium-silicon molecular sieve precursor containing the template agent does not include calcining the dried material.

[0092] According to the present invention, preferably, the amount of the titanium-silicon molecular sieve precursor containing the template agent and the alumina precursor is such that, based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, preferably 70-90 wt%; and the content of alumina is 5-30 wt%, preferably 10-30 wt%.

[0093] The preparation method provided by this invention can significantly reduce the amount of extrusion aid used, thereby significantly reducing the energy consumption and cost of catalyst production. According to this invention, the mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor containing the template agent, specifically 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and any two of these values ​​forming a range, preferably 5-20%.

[0094] The extrusion aid described in this invention can be any of the extrusion aids commonly used in the art, such as guar gum powder, methylcellulose, soluble starch, and citric acid.

[0095] According to the present invention, preferably, the alumina precursor comprises alumina sol and optionally aluminum hydroxide powder.

[0096] According to the present invention, preferably, the mass ratio of aluminum hydroxide powder to aluminum sol is 0-50:50-100, wherein the aluminum sol and aluminum hydroxide powder are calculated as aluminum oxide.

[0097] According to the present invention, preferably, the aluminum sol is an acidic aluminum sol with a pH value of 2-4.

[0098] According to the present invention, preferably, the solid content of the aluminum sol is 20-30 wt%.

[0099] According to the present invention, preferably, the specific surface area of ​​the aluminum hydroxide powder is 270-500 m². 2 / g, pore volume is 0.5-1.2mL / g.

[0100] The present invention does not particularly limit the source of the aluminum sol and aluminum hydroxide powder, as long as the above conditions are met. They can be obtained by commercial purchase or by self-production using conventional methods in the art.

[0101] In the catalyst preparation method of the present invention, water may be added during the mixing and molding process, depending on the specific circumstances, to ensure successful molding.

[0102] This invention does not impose any particular limitation on the order in which the substances are added during the mixing process; they can be added together or separately. To achieve better and faster uniform mixing, this embodiment of the invention employs the method of first adding a titanium-silicon molecular sieve precursor containing a template agent, an extrusion aid, and optionally aluminum hydroxide powder, followed by the sequential addition of aluminum sol and water. Conventional methods such as stirring or ultrasound can be used during the above mixing process to accelerate uniform mixing.

[0103] The present invention does not particularly limit the molding method, and an appropriate method can be selected according to specific circumstances. An exemplary embodiment of the present invention uses extrusion molding.

[0104] The present invention does not impose any particular limitation on the drying process, and it can be carried out with reference to conventional methods in the art. Preferably, the drying conditions include: a temperature of 100-200°C, more preferably 110-150°C; and a time of 1-24 hours, more preferably 2-12 hours.

[0105] The method provided by this invention can shorten the time required for calcination to remove a large amount of pore-forming agent and extrusion aid during the titanium-silicon molecular sieve forming process, reduce energy consumption, and significantly reduce the overall production cost of the catalyst. Preferably, the calcination conditions include: a temperature of 400-800℃, more preferably 500-600℃; and a time of 2-20h, more preferably 6-12h.

[0106] The catalyst preparation method provided by this invention innovatively uses a titanium-silicon molecular sieve precursor with the template agent intact as one of the main raw materials, effectively utilizing the pore-forming function of the template agent during the calcination process and avoiding the use of a large amount of organic pore-forming agents. Preferably, the catalyst preparation method includes not adding pore-forming agents.

[0107] The porogen described in this invention can be any porogen commonly used in the art, examples of which include, but are not limited to: melamine, alkylphenol polyoxyethylene ethers (with 6-12 alkyl carbons, preferably 8-10, and a degree of polymerization of 10-30, preferably 12-24, such as octylphenol polyoxyethylene (15) ether), polyethylene glycol, and polypropylene glycol. These will not be described in detail here.

[0108] The present invention also provides the application of the aforementioned titanium-silicon molecular sieve catalyst or the titanium-silicon molecular sieve catalyst prepared by the aforementioned preparation method in the epoxidation reaction of olefins, preferably in the epoxidation reaction of 3-chloropropene to prepare epichlorohydrin.

[0109] The catalyst provided by this invention has both high strength and high catalytic performance, and is suitable for olefin epoxidation reactions, especially for the preparation of epichlorohydrin by the epoxidation reaction of 3-chloropropene.

[0110] The present invention also provides a method for preparing epichlorohydrin by epoxidation of 3-chloropropene, the method comprising: reacting 3-chloropropene and an aqueous solution of hydrogen peroxide in the presence of a catalyst and a solvent;

[0111] The catalyst is either the aforementioned titanium-silicon molecular sieve catalyst or the titanium-silicon molecular sieve catalyst prepared by the aforementioned preparation method.

[0112] The titanium-silicon molecular sieve catalyst provided by this invention can be dispersed in the liquid within a reactor in the form of particles, or used in the reactor in the form of a bed, preferably in the reactor in the form of a fixed bed. That is, the reaction is carried out in a fixed bed reactor.

[0113] The reaction process described in this invention can be carried out with reference to conventional methods in the art.

[0114] Preferably, the molar ratio of 3-chloropropene to hydrogen peroxide is 0.8-3:1.

[0115] Preferably, the hydrogen peroxide aqueous solution contains 10-90% by mass, for example 20-70%, such as 20%, 30%, 40%, 50%, 60%, or 70%.

[0116] Preferably, the solvent is selected from at least one of alcohols having 1-6 carbon atoms, ketones having 3-4 carbon atoms, ethers having 2-10 carbon atoms, nitriles having 2-4 carbon atoms, and carboxylic acid esters having 2-6 carbon atoms, and more preferably from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, acetone, acetonitrile, and propionitrile. More preferably, the solvent is selected from at least one of alcohols having 1-6 carbon atoms, and more preferably from at least one of methanol, ethanol, and tert-butanol.

[0117] Preferably, the molar ratio of solvent to hydrogen peroxide is 4-20:1, more preferably 5-10:1.

[0118] Preferably, the amount of catalyst used is 0.5-10 wt% of the total mass of the reaction solution, for example, 2-5 wt%.

[0119] It should be noted that the reaction solution here refers to a mixture of solvent, 3-chloropropene, and aqueous hydrogen peroxide solution.

[0120] Preferably, the reaction further includes the addition of an alkaline additive. The present invention does not impose any particular limitation on the type of alkaline additive; any conventional choice in the art is acceptable.

[0121] Preferably, the alkaline additive is selected from at least one of ammonia, alkaline ammonium salts, organic amines, and quaternary ammonium bases.

[0122] More preferably, the basic ammonium salt is selected from at least one of ammonium carbonate, ammonium bicarbonate and ammonium acetate, such as ammonium carbonate and / or ammonium acetate.

[0123] More preferably, the organic amine is selected from at least one of methylamine, ethylamine, propylamine, dimethylamine, trimethylamine, diethylamine, triethylamine, butylamine, pentylamine and hexylamine, for example, at least one of methylamine, ethylamine, propylamine, dimethylamine and diethylamine.

[0124] According to the present invention, preferably, the quaternary ammonium base is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0125] The present invention allows for a wide range of choices regarding the amount of alkaline additive. The preferred amount of alkaline additive is 0.01-0.1% of the total mass of the reaction solution, or the molar ratio of alkaline additive to hydrogen peroxide is 0.001-0.05:1, preferably 0.002-0.003:1.

[0126] It should be noted that the reaction solution here refers to a mixture of solvent, 3-chloropropene, and aqueous hydrogen peroxide solution.

[0127] Preferably, the reaction pressure is 0.1-10 MPa, more preferably 0.2-6 MPa, and even more preferably 0.4-4 MPa.

[0128] Preferably, the reaction temperature is 10-90℃, more preferably 20-80℃, and even more preferably 30-70℃.

[0129] Preferably, the reaction is carried out in a fixed-bed reactor. This preferred embodiment is more advantageous for industrial applications. When the reaction is carried out in a fixed-bed reactor, the feed mass hourly space velocity (WHSV) of hydrogen peroxide is 0.01-10 h⁻¹. -1 .

[0130] In a second aspect, the present invention provides a method for removing hydrogen peroxide from epichlorohydrin wastewater.

[0131] Specifically, the present invention provides a method for removing hydrogen peroxide from epichlorohydrin wastewater, comprising the following steps:

[0132] In a hydrogen atmosphere, epichlorohydrin wastewater is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to convert hydrogen peroxide in the epichlorohydrin wastewater into water; wherein the hydrogenation catalyst comprises an activated carbon support and an active metal component; the active metal component comprises Pd.

[0133] In one embodiment, the hydrogenation catalyst comprises an activated carbon support and an active metal component; the active metal component is Pd.

[0134] In the method for removing hydrogen peroxide from epichlorohydrin wastewater according to the present invention, the hydrogenation catalyst of the present invention uses metal Pd as the active center and activated carbon as the support. It has excellent catalytic activity for the reaction of hydrogen peroxide to produce water, and avoids the generation of oxygen, significantly reduces nitrogen consumption, and improves the technical economy and safety of the reaction process.

[0135] In one embodiment, based on the total weight of the hydrogenation catalyst, the content of the active metal component is 0.1-13% by weight, preferably 0.5-1% by weight. The hydrogenation catalyst provided by this invention can achieve excellent catalytic activity even with a low loading of the active metal component, and can also improve the economic efficiency of treating epichlorohydrin wastewater. When the loading of the metal active component of the hydrogenation catalyst is within the range of this embodiment, especially within the preferred content range, the hydrogenation catalyst can achieve a more excellent hydrogen peroxide removal effect in epichlorohydrin wastewater, improving the hydrogen peroxide conversion rate.

[0136] In one specific embodiment, the total specific surface area of ​​the hydrogenation catalyst is 1100-2000 m². 2 / g, preferably 1500-2000m 2 / g; the particle size is 10-180 mesh, preferably 20-110 mesh, and more preferably 30-80 mesh. The catalyst provided by the present invention has a suitable specific surface area and particle size. The catalyst can be in the form of unground particles. The size of the catalyst particles has a certain influence on the catalytic activity. The larger the size, the lower the mass transfer effect and the lower the activity, requiring a higher catalyst addition amount. However, the catalyst mesh size should not be further reduced, otherwise even if an extremely excessive amount of catalyst is added, the desired effect may not be achieved. Therefore, the catalyst used in the present invention has a particle size range that balances the addition amount and catalytic activity, and is more suitable for use in fixed-bed reactors.

[0137] In a preferred embodiment, the microporous specific surface area of ​​the hydrogenation catalyst accounts for 90-100% of the total specific surface area. In this invention, micropores refer to pores with a diameter less than 2 nm. The hydrogenation catalyst provided by this invention has a high proportion of microporous specific surface area, which is more conducive to improving reaction activity.

[0138] In one embodiment, the hydrogenation catalyst is prepared by a method comprising the following steps:

[0139] (1) The activated carbon support is impregnated with an active metal precursor solution, dried and calcined to obtain a catalyst precursor; optionally, the active metal precursor is selected from one or more of palladium acetate, palladium nitrate, palladium chloride and palladium oxalate.

[0140] (2) The catalyst precursor is reduced under hydrogen conditions.

[0141] In one specific embodiment, in step (1), the concentration of palladium ions in the active metal precursor solution is 0.05-7% by weight, preferably 0.25-0.50% by weight. Preferably, the impregnation treatment is equal volume impregnation, which is a conventional operation in the art. The impregnation temperature can be 20-30°C, and the impregnation time can be 10-15h.

[0142] In one embodiment, the drying conditions include: a drying temperature of 100-120°C and a drying time of 6-10 hours. In this invention, the drying process removes the solvent to improve the efficiency of subsequent calcination and reduction.

[0143] In a preferred embodiment, the conditions for the calcination reduction treatment in step (2) include: a reduction temperature of 300-750℃, preferably 300-620℃; a reduction time of 2-8h, preferably 3-6h; and a hydrogen flow rate of 5-100mL / min, preferably 5-60mL / min. According to the process conditions in this embodiment, especially the preferred process conditions, a hydrogenation catalyst with higher catalytic performance can be prepared, thereby improving the hydrogen peroxide conversion rate.

[0144] In one specific embodiment, the epichlorohydrin wastewater originates from the reaction of 3-chloropropene and hydrogen peroxide to synthesize epichlorohydrin. Specifically, the epichlorohydrin wastewater is a liquid obtained after separating the unreacted substrate 3-chloropropene and the target product epichlorohydrin from the reaction solution following the epoxidation reaction. In particular, it refers to a waste liquid containing solvents such as methanol, water, and hydrogen peroxide obtained after mixing a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, solvents such as methanol, water, and hydrogen peroxide with an extractant following the epoxidation reaction.

[0145] Optionally, based on the total weight of the epichlorohydrin wastewater, the hydrogen peroxide content is 0.05-3% by weight, preferably 0.1-0.5% by weight. The method provided in this embodiment can effectively remove hydrogen peroxide from a wide range of contents in epichlorohydrin wastewater and has a wide range of applications.

[0146] In one specific embodiment, the epichlorohydrin wastewater further includes methanol and water; based on the total weight of the epichlorohydrin wastewater, the methanol content is 20-80% by weight, preferably 40-60% by weight.

[0147] In one embodiment, in the catalytic hydrogenation reaction, the weight ratio of epichlorohydrin wastewater to hydrogenation catalyst is 100:(0.1-7), preferably 100:(0.1-1.5). Using the weight ratio of epichlorohydrin wastewater to hydrogenation catalyst provided in this embodiment, particularly within the preferred range, is beneficial for improving the conversion rate of hydrogen peroxide.

[0148] In one embodiment, the conditions for the catalytic hydrogenation reaction include: a reaction temperature of 20-50°C, a reaction time of 10-60 min, and a hydrogen pressure of 1-10 bar, which is beneficial for achieving efficient removal of hydrogen peroxide from epichlorohydrin wastewater.

[0149] In a preferred embodiment, the conditions for the catalytic hydrogenation reaction include: a reaction temperature of 25-45°C, a reaction time of 20-60 min, and a hydrogen pressure of 2-10 bar, which can further improve the conversion rate of hydrogen peroxide in epichlorohydrin wastewater.

[0150] According to the present invention, the hydrogen peroxide hydrogenation reaction process is stirred, and the required reactor can be a stainless steel reactor with a polytetrafluoroethylene liner, a Hastelloy reactor, or a reactor conventionally used in the art.

[0151] In a third aspect, the present invention provides a method for separating 3-chloropropene and 1-chloropropane, and a method for producing epichlorohydrin.

[0152] Specifically, the present invention provides a method for separating 3-chloropropene and 1-chloropropane, comprising the following steps:

[0153] (1) A mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is subjected to a first distillation separation in a first distillation column to obtain a top product containing 3-chloropropene and 1-chloropropane and a bottom product containing epichlorohydrin; wherein, in the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1;

[0154] (2) Under the action of a catalyst, the top product obtained in step (1) is reacted with hydrogen peroxide; wherein the molar ratio of 3-chloropropene to hydrogen peroxide in the top product is 0.7-0.99:1.

[0155] (3) The reaction product obtained in step (2) is subjected to a second distillation in a second distillation column to obtain a top product rich in 1-chloropropane and a bottom product rich in epichlorohydrin; wherein the mass fraction of 1-chloropropane in the top product is not less than 10% and the mass fraction of 1-chloropropane in the bottom product is not more than 0.1%.

[0156] According to the present invention, preferably, the total mass fraction of 3-chloropropene and 1-chloropropane in the top product obtained in step (1) is not less than 99%.

[0157] According to the present invention, preferably, the mass content of 3-chloropropene in the top product obtained in step (1) is 80-98%, more preferably 90-97%; and the mass content of 1-chloropropane is 2-20%, more preferably 3-10%.

[0158] The present invention does not impose any particular limitations on the first distillation column and the second distillation column, and various distillation columns conventionally used in the art can be used, as long as they can achieve their respective distillation and separation purposes.

[0159] The present invention does not impose any particular limitation on the conditions for the first distillation separation; the separation effect can be achieved by referring to conventional methods in the art.

[0160] According to the present invention, preferably, the conditions for the first distillation separation in step (1) include: the bottom temperature of the column is 81-129°C, the top temperature of the column is 30-60°C, the top pressure of the column is 60-101 kPaA, the number of theoretical plates is 10-50, and the top reflux ratio is 1-50.

[0161] In this invention, pressure refers to gauge pressure unless otherwise specified. For example, kPaA represents absolute pressure.

[0162] According to the present invention, preferably, in the reaction described in step (2), the conversion rate of 3-chloropropene is not less than 95%, preferably not less than 98%; and the conversion rate of 1-chloropropane is not more than 5%, preferably not more than 1%.

[0163] The present invention allows for a wide range of conditions for the reaction described in step (2), as long as the conversion rates of 3-chloropropene and 1-chloropropane meet the above conditions.

[0164] According to the present invention, preferably, the reaction temperature of the reaction in step (2) is 10-90°C, more preferably 20-80°C, and more preferably 30-70°C.

[0165] According to the present invention, the molar ratio of 3-chloropropene to hydrogen peroxide in the top product of the column is 0.7-0.99:1, preferably 0.8-0.99:1. In this preferred embodiment, the excess hydrogen peroxide is beneficial for achieving complete conversion of 3-chloropropene.

[0166] Preferably, the hydrogen peroxide is provided in the form of an aqueous solution of hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the aqueous solution is not less than 50%, preferably 50-70%. The inventors of this invention unexpectedly discovered that using a high-concentration aqueous solution of hydrogen peroxide can effectively reduce the water content in the reaction solution, which has an important promoting effect on suppressing the hydrolysis side reaction of epichlorohydrin and improving the selectivity of epichlorohydrin.

[0167] According to the present invention, preferably, when the reaction in step (2) is a batch reaction, the mass amount of catalyst is 0.1-40% of the total mass of the liquid phase feed, preferably 0.5-20%; when the reaction in step (2) is a continuous reaction, the feed mass hourly space velocity of hydrogen peroxide is 0.01-10 h⁻¹. -1 .

[0168] According to the present invention, preferably, in step (2), the reaction pressure is 0.1-10 MPa, more preferably 0.2-6 MPa, and more preferably 0.4-4 MPa.

[0169] According to the present invention, preferably, the reaction in step (2) is carried out in a fixed-bed reactor. This preferred embodiment is more advantageous for industrial applications.

[0170] The present invention does not have any particular limitation on the type of catalyst used in step (2), and can be any conventional choice in the art.

[0171] According to the present invention, preferably, the catalyst in step (2) is a titanium-silicon molecular sieve catalyst, which preferably includes titanium-silicon molecular sieve and alumina. Based on the total mass of the titanium-silicon molecular sieve catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, preferably 70-90 wt%; and the content of alumina is 5-30 wt%, preferably 10-30 wt%.

[0172] The side crushing strength of the catalyst is 60-120 N / cm, preferably 60-100 N / cm.

[0173] According to the present invention, preferably, the catalyst in step (2) is the titanium-silicon molecular sieve catalyst provided in the first aspect of the present invention. The parameter characteristics and preparation method of this catalyst will not be described in detail here.

[0174] According to the present invention, preferably, a solvent is also added to the reaction in step (2). The present invention does not impose any particular limitation on the type of solvent, and any conventional choice in the art is acceptable. Preferably, the solvent is selected from at least one of alcohols with 1-6 carbon atoms, ketones with 3-4 carbon atoms, ethers with 2-10 carbon atoms, nitriles with 2-4 carbon atoms, and carboxylic acid esters with 2-6 carbon atoms; more preferably, it is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, acetone, acetonitrile, and propionitrile.

[0175] The present invention does not impose a particular limitation on the amount of solvent used, and can be carried out with reference to conventional methods in the art. Preferably, the molar ratio of solvent to 3-chloropropene is 4-20:1, more preferably 5-10:1.

[0176] According to the present invention, preferably, an alkaline additive is also added to the reaction in step (2). The present invention does not particularly limit the type of alkaline additive and can use conventional choices in the art. Preferably, the alkaline additive is selected from at least one of ammonia, basic ammonium salts, organic amines, and quaternary ammonium bases.

[0177] According to the present invention, preferably, the basic ammonium salt is selected from at least one of ammonium carbonate, ammonium bicarbonate and ammonium acetate.

[0178] According to the present invention, preferably, the organic amine is selected from at least one of methylamine, ethylamine, propylamine, dimethylamine, trimethylamine, diethylamine, triethylamine, butylamine, pentylamine and hexylamine.

[0179] According to the present invention, preferably, the quaternary ammonium base is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0180] The present invention does not impose a particular limitation on the amount of alkaline additive used, and can be carried out with reference to conventional methods in the art. Preferably, the molar ratio of alkaline additive to hydrogen peroxide is 0.001-0.05:1, more preferably 0.002-0.003:1, or the mass of alkaline additive is preferably 0.01-0.1% of the total mass of the reaction solution, where the reaction solution refers to a mixture of solvent, 3-chloropropene, and aqueous hydrogen peroxide solution.

[0181] Preferably, the reaction in step (2) is carried out under stirring conditions. The present invention does not impose any particular limitation on the stirring; it can be appropriately selected according to actual conditions to achieve a rapid and uniform reaction.

[0182] According to the present invention, preferably, the conditions for the second distillation separation in step (3) include: the bottom temperature of the column is 81-119°C, the top temperature of the column is 40-50°C, the top pressure of the column is 60-101 kPaA, the theoretical number of plates is 10-50, and the top reflux ratio is 0.5-5.

[0183] According to a specific embodiment of the present invention, step (3) the second distillation separation is atmospheric distillation.

[0184] In this invention, atmospheric distillation refers to distillation performed while maintaining a top pressure of approximately 101 kPaA.

[0185] According to the present invention, preferably, the epichlorohydrin mass fraction in the bottom product containing epichlorohydrin obtained in step (1) is not less than 99%.

[0186] According to the present invention, preferably, the bottom product of the first distillation column in step (1) and the bottom product of the second distillation column in step (3) are purified to obtain epichlorohydrin product. The present invention does not particularly limit the purification method, and can refer to conventional methods in the art; these methods will not be described in detail here.

[0187] The present invention allows for a wide range of choices regarding the specific composition of the mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin. Preferably, in the mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, the mass fraction of epichlorohydrin is 10-90%, specifically 10%, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and any two of these values; the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, specifically 10%, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and any two of these values; and the mass ratio of 3-chloropropene to 1-chloropropane is 90:10-97:3.

[0188] The mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin described in this invention may also contain other substances. Since the presence of other substances does not affect the implementation of the method described in this application, they are not shown here.

[0189] According to the present invention, preferably, the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is derived from the hydroperoxide process for the production of epichlorohydrin.

[0190] This invention does not specifically limit the preparation method of the mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin in the hydrogen peroxide method for epichlorohydrin production, and can refer to conventional methods in the art. Preferably, the preparation method of the mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin includes: contacting 3-chloropropene and hydrogen peroxide with an epoxidation catalyst in the presence of methanol to carry out an epoxidation reaction.

[0191] The present invention does not particularly limit the epoxidation reaction, and it can be carried out with reference to conventional methods in the art. Preferably, the molar ratio of 3-chloropropene to hydrogen peroxide is 1-15:1, more preferably 1-10:1.

[0192] Even when using industrial-grade 3-chloropropene (3-chloropropene purity 99 wt%), it is inevitable that it will carry impurities such as 1-chloropropane. 1-chloropropane impurities do not participate in the reaction, but they accumulate continuously during the 3-chloropropene cycle, resulting in a high concentration of 1-chloropropane.

[0193] The present invention also provides a method for producing epichlorohydrin, comprising the following steps:

[0194] S1. In methanol solvent, 3-chloropropene containing 1-chloropropane and hydrogen peroxide are subjected to an epoxidation reaction to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide.

[0195] S2. The solution containing epichlorohydrin, 3-chloropropene, 1-chloropropene, methanol, water and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropene and epichlorohydrin and a solution containing methanol, water and hydrogen peroxide.

[0196] S3. Separating 3-chloropropene and 1-chloropropane from a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the method for separating 3-chloropropene and 1-chloropropane is the method for separating 3-chloropropene and 1-chloropropane described in the third aspect above.

[0197] S4. In a hydrogen atmosphere, the solution containing methanol, water and hydrogen peroxide obtained in S2 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing methanol and water; then, optionally, the solution containing methanol and water is subjected to distillation to obtain methanol.

[0198] The present invention does not have any particular limitations on steps S1, S2, and S4, and they can be performed with reference to conventional methods in the art.

[0199] According to the present invention, preferably, step S4 is carried out according to the method for removing hydrogen peroxide from epichlorohydrin wastewater as described in the second aspect of the present invention.

[0200] According to the present invention, preferably, the methanol obtained in S4 is recycled.

[0201] According to the present invention, preferably, the bottom product rich in epichlorohydrin obtained in S3 is returned to the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide in S1.

[0202] In this invention, the separation of the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropene, a solvent (such as a C1-6 alcohol, such as methanol), water, and hydrogen peroxide after mixing with an extractant is performed according to methods known in the art, such as those disclosed in CN103420947A and CN103772326A. The extractant comprises water and an organic compound. The organic compound has a lower extraction capacity for the solvent (such as a C1-6 alcohol, such as methanol) than water but a higher extraction capacity for epichlorohydrin than water. Furthermore, the organic compound has a different boiling point and density than water compared to epichlorohydrin. Relative to 100 parts by mass of the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropene, a solvent (such as a C1-6 alcohol, such as methanol), water, and hydrogen peroxide, the amount of water used is 10-1000 parts by mass, and the amount of the organic compound is 10-1000 parts by mass. Preferably, the organic compound is 3-chloropropene. Mixing with the extractant can be carried out at any suitable temperature, provided that no phase change occurs in the liquid. For example, mixing with the extractant can be carried out at temperatures ranging from -10°C to 80°C. Separation after mixing can be phase separation, yielding a liquid phase rich in epichlorohydrin (the organic compound can be separated by distillation to obtain a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, with the organic compound stream partially or entirely returned for extraction) and a liquid phase rich in solvent (such as C1-6 alcohol, such as methanol) (i.e., a solution containing solvent (such as C1-6 alcohol, such as methanol), water, and hydrogen peroxide). When the organic compound is 3-chloropropene, phase separation can directly yield a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, and a solution containing solvent (such as C1-6 alcohol, such as methanol), water, and hydrogen peroxide. Extraction can be single-stage, two-stage, or multi-stage extraction.

[0203] The present invention specifically provides the following technical solution:

[0204] 1. A method for producing epichlorohydrin, the method comprising the following steps:

[0205] A1. In the presence of a catalyst and solvent, 3-chloropropene and hydrogen peroxide are reacted to produce a mixture containing epichlorohydrin and a waste liquid containing hydrogen peroxide; and

[0206] A2. In a hydrogen atmosphere, waste liquid containing hydrogen peroxide is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst.

[0207] The method may also optionally include the following steps:

[0208] A3. Separate the mixture containing epichlorohydrin;

[0209] Its features are,

[0210] The catalyst used in step A1 is a titanium-silicon molecular sieve catalyst, which comprises titanium-silicon molecular sieve and inorganic oxides. Based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, and the content of inorganic oxides is 5-30 wt%; wherein, the lateral crushing strength of the catalyst is 60-150 N / cm; and / or

[0211] The hydrogenation catalyst used in step A2 includes an activated carbon support and an active metal component; the active metal component includes Pd, preferably Pd; and / or

[0212] The catalyst used in step A1 is prepared by a process including the following steps: mixing and molding a titanium-silicon molecular sieve precursor containing a template agent, an inorganic oxide precursor (such as an alumina precursor), and an extrusion aid, followed by drying and calcination; and / or

[0213] The hydrogenation catalyst used in step A2 is prepared by a process including the following steps: (1) impregnating and drying an activated carbon support with an active metal precursor solution to obtain a catalyst precursor, wherein the active metal component includes Pd, preferably Pd; and (2) calcining and reducing the catalyst precursor under hydrogen conditions.

[0214] The catalytic hydrogenation reaction in step A2 of this invention refers to the reaction of hydrogen peroxide with hydrogen to form water. This reaction does not produce oxygen.

[0215] 2. A method for producing epichlorohydrin according to any one of the foregoing technical solutions, characterized in that...

[0216] The catalyst used in step A1 has the following properties:

[0217] The inorganic oxide is selected from alumina, silicon oxide, and boron oxide, and alumina accounts for 80 wt% or more of the inorganic oxide, such as 90 wt% or more, 95 wt% or more, 96 wt% or more, 97 wt% or more, 98 wt% or more, 99 wt% or more, preferably, the inorganic oxide is alumina; and / or

[0218] The total content of titanium silicate molecular sieves and inorganic oxides is ≥98 wt%, or ≥99 wt%, or ≥99.5 wt%, or ≥99.9 wt%, or 98-100 wt%, or 98-99.99 wt%, or 99.9-99.99 wt%; and / or

[0219] The contents of titanium-silicon molecular sieve and inorganic oxide are 70-90 wt% and 10-30 wt% respectively; or 70-87 wt% and 13-30 wt%; or 70-80 wt% and 20-30 wt%; or 70-75 wt% and 25-30 wt%; or 75-87 wt% and 13-25 wt%; or 75-80 wt% and 20-25 wt%; or 80-87 wt% and 13-20 wt%; and / or

[0220] The lateral crushing strength of the catalyst is: 60-150 N / cm, or 60-120 N / cm, or 60-100 N / cm, or 70-150 N / cm, or 70-120 N / cm, or 70-100 N / cm, or 71.3-120 N / cm, or 71.3-100 N / cm; and / or

[0221] In the titanium-silicon molecular sieve, the mass fraction of titanium, calculated as TiO2, is 1-10%, preferably 1-5%; and / or

[0222] The titanium-silicon molecular sieve is selected from at least one of titanium-silicon molecular sieves having MFI structure, MEL structure, BEA structure, MSE structure and MWW structure. Preferably, the titanium-silicon molecular sieve is a titanium-silicon molecular sieve with MFI structure, such as TS-1 molecular sieve.

[0223] and / or

[0224] The catalyst used in step A2 has the following properties:

[0225] Based on the total weight of the hydrogenation catalyst, the content of the active metal component is 0.1-13% by weight, preferably 0.5-1% by weight; and / or

[0226] The total specific surface area of ​​the hydrogenation catalyst is 1100-2000 m². 2 / g, preferably 1500-2000m 2 / g; particle size of 10-180 mesh, preferably 20-110 mesh, more preferably 30-80 mesh; and / or

[0227] The microporous specific surface area of ​​the hydrogenation catalyst accounts for 90-100% of the total specific surface area.

[0228] 3. A method for producing epichlorohydrin according to any one of the foregoing technical solutions, characterized in that...

[0229] The catalyst used in step A1 is prepared by a process including the following steps:

[0230] A titanium-silicon molecular sieve precursor containing a template agent, an inorganic oxide precursor (such as an alumina precursor), and an extrusion aid are mixed and molded, then dried and calcined.

[0231] The mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor, preferably 5-20%; and / or

[0232] The extrusion aid is selected from guar gum powder, methylcellulose, soluble starch, and citric acid; and / or

[0233] In the titanium-silicon molecular sieve precursor, the content of the template agent is 1-20 wt%, preferably 1-10 wt%; and / or

[0234] In the titanium-silicon molecular sieve precursor, based on the dry basis mass of the titanium-silicon molecular sieve precursor and calculated as TiO2, the mass fraction of titanium is 1-10%, preferably 1-5%; and / or

[0235] The template agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; and / or

[0236] The preparation method of the titanium-silicon molecular sieve precursor containing the template agent includes: mixing a titanium source, a silicon source, a template agent, and water; performing hydrothermal crystallization; and then drying; and / or

[0237] The method for preparing the titanium-silicon molecular sieve precursor containing the template agent does not include calcining the dried material; and / or

[0238] The amount of the template agent-containing titanium-silicon molecular sieve precursor and the inorganic oxide precursor (such as an alumina precursor) used in the prepared catalyst is such that, based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, preferably 70-90 wt%; the content of inorganic oxide (such as alumina) is 5-30 wt%, preferably 10-30 wt%; and / or

[0239] The alumina precursor comprises aluminum sol and optionally aluminum hydroxide powder or hydrated alumina powder (e.g., alumina monohydrate and / or alumina trihydrate); preferably, the mass ratio of aluminum hydroxide powder or hydrated alumina powder to aluminum sol is 0-50:50-100, wherein the aluminum sol, water, and alumina powder are calculated as alumina; and / or preferably, the aluminum sol is an acidic aluminum sol with a pH of 2-4; and / or preferably, the solid content of the aluminum sol is 20-30 wt%; and / or preferably, the specific surface area of ​​the aluminum hydroxide powder or hydrated alumina powder is 270-500 m² / g. 2 / g, pore volume of 0.5-1.2 mL / g; and / or

[0240] The calcination conditions include: a temperature of 400-800℃, preferably 500-600℃; a time of 2-20h, preferably 6-12h; and / or

[0241] The method for preparing the catalyst includes not adding a pore-forming agent;

[0242] and / or

[0243] The hydrogenation catalyst used in step A2 is prepared by a process including the following steps:

[0244] (1) An activated carbon support is impregnated with an active metal precursor solution and then dried to obtain a catalyst precursor; wherein

[0245] The active metal precursor is selected from one or more of palladium acetate, palladium nitrate, palladium chloride, and palladium oxalate, preferably palladium chloride; and / or

[0246] The concentration of palladium ions in the active metal precursor solution is 0.05-7% by weight, for example, 0.05-5.5% by weight, or 0.25-0.50% by weight; and / or

[0247] The impregnation treatment is an equal volume impregnation; and / or

[0248] The conditions for the impregnation treatment include: an impregnation temperature of 20-30℃ and an impregnation time of 10-15 hours; and / or

[0249] The drying conditions include: a drying temperature of 100-120℃ and a drying time of 6-10 hours;

[0250] (2) The catalyst precursor is subjected to calcination and reduction treatment under hydrogen conditions; wherein the conditions for calcination and reduction treatment include:

[0251] The reduction temperature is 300-750℃, preferably 300-620℃;

[0252] The reduction time is 2-8 hours, preferably 3-6 hours;

[0253] The hydrogen flow rate is 5-100 mL / min, preferably 5-60 mL / min.

[0254] 4. A method for producing epichlorohydrin according to any one of the foregoing technical solutions, characterized in that the conditions for the epoxidation reaction in step A1 include:

[0255] The molar ratio of 3-chloropropene to hydrogen peroxide is 0.8-3:1; and / or

[0256] The hydrogen peroxide is provided in the form of an aqueous solution of hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the aqueous solution is 10-90%, for example 20-70%, such as 20%, 30%, 40%, 50%, 60%, or 70%; and / or

[0257] The solvent is selected from at least one of alcohols having 1-6 carbon atoms, ketones having 3-4 carbon atoms, ethers having 2-10 carbon atoms, nitriles having 2-4 carbon atoms, and carboxylic acid esters having 2-6 carbon atoms; preferably, it is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, acetone, acetonitrile, and propionitrile; more preferably, the solvent is methanol; and / or

[0258] The molar ratio of solvent to hydrogen peroxide is 4-20:1, preferably 5-10:1; and / or

[0259] The amount of catalyst used is 0.5-10 wt% of the total mass of the reaction solution, for example, 2-5 wt%.

[0260] 5. A method for producing epichlorohydrin according to any one of the foregoing technical solutions, characterized in that the conditions for the catalytic hydrogenation reaction in step A2 include:

[0261] The reaction temperature is 20-50℃, the reaction time is 10-60 min, and the hydrogen pressure is 1-10 bar; preferably, the reaction temperature is 25-45℃, the reaction time is 20-60 min, and the hydrogen pressure is 2-10 bar; and / or

[0262] Based on the total weight of the waste liquid containing hydrogen peroxide, the hydrogen peroxide content is 0.05-3% by weight, preferably 0.1-0.5% by weight; and / or

[0263] The weight ratio of the waste liquid containing hydrogen peroxide to the hydrogenation catalyst is 100:0.1-7, preferably 100:0.1-1.5.

[0264] 6. A method for producing epichlorohydrin according to any one of the foregoing technical solutions, characterized in that the method comprises the following steps:

[0265] A1. In the presence of a catalyst, 3-chloropropene containing 1-chloropropane and hydrogen peroxide are subjected to an epoxidation reaction in methanol solvent to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide.

[0266] The solution containing epichlorohydrin, 3-chloropropene, 1-chloropropene, methanol, water and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropene and epichlorohydrin and a solution containing methanol, water and hydrogen peroxide.

[0267] A2. In a hydrogen atmosphere, the solution containing methanol, water and hydrogen peroxide obtained in A1 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing methanol and water; then, optionally, the solution containing methanol and water is subjected to distillation to obtain methanol for recycling.

[0268] A3. Separate 3-chloropropene and 1-chloropropane from the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin obtained in A1.

[0269] 7. The method for producing epichlorohydrin according to the aforementioned technical solution 6, characterized in that...

[0270] In the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin obtained in step A1, the mass fraction of epichlorohydrin is 10-90%, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1, for example 90:10-97:3;

[0271] In the solution containing methanol, water, and hydrogen peroxide obtained in step A1, the hydrogen peroxide content is 0.05-3% by weight, preferably 0.1-0.5% by weight; the methanol content is 20-80% by weight, preferably 40-60% by weight; and / or

[0272] In the catalytic hydrogenation reaction of step A2, the weight ratio of the solution containing methanol, water and hydrogen peroxide to the hydrogenation catalyst is 100:0.1-7, preferably 100:0.1-1.5.

[0273] 8. A method for producing epichlorohydrin according to any one of the foregoing technical solutions, characterized in that the method comprises the following steps:

[0274] A1. In the presence of a catalyst and a solvent, an aqueous solution of 3-chloropropene containing 1-chloropropane and hydrogen peroxide is subjected to an epoxidation reaction to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, solvent, water and hydrogen peroxide; the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, solvent, water and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, and a waste liquid containing solvent, water and hydrogen peroxide;

[0275] In the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, the mass fraction of epichlorohydrin is 10-90%, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1, for example 90:10-97:3;

[0276] A2. In a hydrogen atmosphere, the waste liquid containing solvent, water, and hydrogen peroxide obtained in step A1 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing solvent and water; then, optionally, the solution containing solvent and water is subjected to distillation to obtain the solvent; and

[0277] A3. Separating a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, the separation methods include:

[0278] (1) The mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is subjected to a first distillation separation in a first distillation column to obtain a top product containing 3-chloropropene and 1-chloropropane and a bottom product containing epichlorohydrin.

[0279] (2) Under the action of a catalyst, the top product obtained in step (1) is reacted with hydrogen peroxide; wherein, the molar ratio of 3-chloropropene to hydrogen peroxide in the top product is 0.7-0.99:1, for example 0.8-0.99:1; preferably, the catalyst in step (2) is selected from any one of the aforementioned technical solutions of the titanium-silicon molecular sieve catalyst.

[0280] (3) The reaction product obtained in step (2) is subjected to a second distillation in a second distillation column to obtain a top product rich in 1-chloropropane and a bottom product rich in epichlorohydrin; wherein the mass fraction of 1-chloropropane in the top product is not less than 10% and the mass fraction of 1-chloropropane in the bottom product is not more than 0.1%.

[0281] 9. The method for producing epichlorohydrin according to the aforementioned technical solution 8, characterized in that...

[0282] In the top product obtained in step A3(1), the total mass fraction of 3-chloropropene and 1-chloropropane is not less than 99%; and / or

[0283] In the top product obtained in step A3(1), the mass content of 3-chloropropene is 80-98%, preferably 90-97%; the mass content of 1-chloropropane is 2-20%, preferably 3-10%; and / or

[0284] The distillation separation conditions described in step A3(1) include: bottom temperature of 81-129℃, top temperature of 30-60℃, top pressure of 60-101kPaA, theoretical plate number of 10-50, and top reflux ratio of 1-50.

[0285] 10. A method for producing epichlorohydrin according to any one of the aforementioned technical solutions 8-9, characterized in that in the reaction described in step A3 (2),

[0286] The conversion rate of 3-chloropropene is not less than 95%, preferably not less than 98%; the conversion rate of 1-chloropropane is not more than 5%, preferably not more than 1%; and / or

[0287] The reaction temperature is 10-90℃, preferably 20-80℃, more preferably 30-70℃; and / or

[0288] The hydrogen peroxide is provided in the form of an aqueous solution of hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the aqueous solution is not less than 50%, preferably 50-70%; and / or

[0289] The catalyst is used at a mass ratio of 0.1-40% of the total mass of the liquid-phase feed, preferably 0.5-20%; and / or

[0290] The reaction is carried out in a fixed-bed reactor.

[0291] 11. A method for producing epichlorohydrin according to any one of the aforementioned technical solutions 8-10, characterized in that...

[0292] In step A3(2), a solvent is also added to the reaction, wherein

[0293] The solvent is selected from at least one of alcohols having 1-6 carbon atoms, ketones having 3-4 carbon atoms, ethers having 2-10 carbon atoms, nitriles having 2-4 carbon atoms, and carboxylic acid esters having 2-6 carbon atoms; preferably, the solvent is methanol; and / or

[0294] The molar ratio of solvent to 3-chloropropene is 4-20:1; and / or

[0295] The molar ratio of solvent to hydrogen peroxide is 4-20:1, for example, 5-10:1;

[0296] and / or

[0297] In step (2), an alkaline additive is also added to the reaction, wherein...

[0298] The alkaline additive is selected from at least one of ammonia, alkaline ammonium salts, organic amines, and quaternary ammonium bases; and / or

[0299] The molar ratio of alkaline additive to hydrogen peroxide is 0.001-0.05:1.

[0300] 12. A method for producing epichlorohydrin according to any one of the aforementioned technical solutions 8-11, characterized in that...

[0301] The distillation separation conditions described in step (3) include: bottom temperature of 81-119℃, top temperature of 40-50℃, top pressure of 60-101kPaA, theoretical plate number of 10-50, and top reflux ratio of 0.5-5.

[0302] 13. A method for producing epichlorohydrin according to any one of the aforementioned technical solutions 6-11, characterized in that...

[0303] Mixing with the extractant at a temperature ranging from -10°C to 80°C; and / or

[0304] The extractant comprises water and an organic compound, wherein the amount of water and the amount of the organic compound are 10-1000 parts by mass relative to 100 parts by mass of the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, solvent, water and hydrogen peroxide.

[0305] Preferably, the organic compound has a lower ability to extract the solvent than water and a higher ability to extract epichlorohydrin than water, and the organic compound has a different boiling point than epichlorohydrin and a different density than water; and / or

[0306] Preferably, the organic compound is 3-chloropropene.

[0307] A1. A titanium-silicon molecular sieve catalyst, characterized in that...

[0308] The catalyst comprises titanium silicate molecular sieve and alumina, wherein the content of titanium silicate molecular sieve is 70-95 wt% and the content of alumina is 5-30 wt% based on the total mass of the catalyst.

[0309] The side crushing strength of the catalyst is 60-120 N / cm.

[0310] A2. The catalyst according to technical solution A1, wherein,

[0311] Based on the total mass of the catalyst, the content of titanium silicate molecular sieve is 70-90 wt%, and the content of alumina is 10-30 wt%.

[0312] Preferably, the lateral crushing strength of the catalyst is 60-100 N / cm.

[0313] A3. The catalyst according to technical solution A1 or A2, wherein,

[0314] In the titanium-silicon molecular sieve, the mass fraction of titanium, calculated as TiO2, is 1-10%, preferably 1-5%.

[0315] Preferably, the titanium-silicon molecular sieve is selected from at least one of titanium-silicon molecular sieves having MFI structure, MEL structure, BEA structure, MSE structure and MWW structure, preferably a titanium-silicon molecular sieve having MFI structure, and more preferably TS-1 molecular sieve.

[0316] A4. A method for preparing a titanium-silicon molecular sieve catalyst, characterized in that the method includes: mixing and molding a titanium-silicon molecular sieve precursor containing a template agent, an alumina precursor, and an extrusion aid, followed by drying and calcination;

[0317] The mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor.

[0318] A5. According to the method described in technical solution A4, wherein,

[0319] The content of the template agent in the titanium-silicon molecular sieve precursor is 1-20 wt%, preferably 1-10 wt%.

[0320] Preferably, in the titanium-silicon molecular sieve precursor, the mass fraction of titanium, based on the dry basis of the titanium-silicon molecular sieve precursor and calculated as TiO2, is 1-10%, preferably 1-5%.

[0321] Preferably, the template agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide;

[0322] Preferably, the preparation method of the titanium-silicon molecular sieve precursor containing the template agent includes: mixing a titanium source, a silicon source, a template agent and water, performing hydrothermal crystallization, and then drying;

[0323] Preferably, the method for preparing the titanium-silicon molecular sieve precursor containing the template agent does not include calcining the dried material.

[0324] A6. The method described according to technical solution A4 or A5, wherein,

[0325] The amount of the titanium-silicon molecular sieve precursor containing the template agent and the alumina precursor is such that, based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, preferably 70-90 wt%; and the content of alumina is 5-30 wt%, preferably 10-30 wt%.

[0326] Preferably, the mass of the extrusion aid is 5-20% of the dry basis mass of the titanium-silicon molecular sieve precursor.

[0327] A7. The method described according to any one of technical solutions A4-A6, wherein,

[0328] The alumina precursor includes alumina sol and optionally aluminum hydroxide powder;

[0329] Preferably, the mass ratio of aluminum hydroxide powder to aluminum sol is 0-50:50-100, wherein the aluminum sol and aluminum hydroxide powder are calculated as aluminum oxide;

[0330] Preferably, the aluminum sol is an acidic aluminum sol with a pH value of 2-4;

[0331] Preferably, the solid content of the aluminum sol is 20-30 wt%.

[0332] Preferably, the aluminum hydroxide powder has a specific surface area of ​​270-500 m² / g and a pore volume of 0.5-1.2 mL / g.

[0333] A8. The method described according to any one of technical solutions A4-A7, wherein,

[0334] The calcination conditions include: a temperature of 400-800℃, preferably 500-600℃; and a time of 2-20h, preferably 6-12h.

[0335] Preferably, the method for preparing the catalyst does not include the addition of a pore-forming agent.

[0336] A9. The application of a titanium-silicon molecular sieve catalyst according to any one of technical solutions A1-A3 or a titanium-silicon molecular sieve catalyst prepared by any one of technical solutions A4-A8 in the epoxidation reaction of olefins, preferably in the epoxidation reaction of 3-chloropropene to prepare epichlorohydrin.

[0337] A10. A method for preparing epichlorohydrin by epoxidation of 3-chloropropene, characterized in that the method comprises: reacting 3-chloropropene and an aqueous solution of hydrogen peroxide in the presence of a catalyst and a solvent;

[0338] The catalyst is a titanium-silicon molecular sieve catalyst as described in any one of technical solutions A1-A3 or a titanium-silicon molecular sieve catalyst prepared by any one of technical solutions A4-A8.

[0339] Preferably, the reaction is carried out in a fixed-bed reactor.

[0340] B1. A method for removing hydrogen peroxide from epichlorohydrin wastewater, characterized by comprising the following steps:

[0341] In a hydrogen atmosphere, epichlorohydrin wastewater is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to convert hydrogen peroxide in the epichlorohydrin wastewater into water; wherein the hydrogenation catalyst comprises an activated carbon support and an active metal component; the active metal component comprises Pd.

[0342] B2. The method according to technical solution B1, characterized in that, based on the total weight of the hydrogenation catalyst, the content of the active metal component is 0.1-13% by weight, preferably 0.5-1% by weight.

[0343] B3. The method according to technical solution B1, characterized in that the total specific surface area of ​​the hydrogenation catalyst is 1100-2000 m2 / g, preferably 1500-2000 m2 / g; the particle size is 10-180 mesh, preferably 20-110 mesh;

[0344] Optionally, the microporous specific surface area of ​​the hydrogenation catalyst accounts for 90-100% of the total specific surface area.

[0345] B4. The method according to technical solution B1, characterized in that the hydrogenation catalyst is prepared by a method comprising the following steps:

[0346] (1) The activated carbon support is impregnated with an active metal precursor solution and then dried to obtain a catalyst precursor; optionally, the active metal precursor is selected from one or more of palladium acetate, palladium nitrate, palladium chloride and palladium oxalate, preferably palladium chloride.

[0347] (2) The catalyst precursor is subjected to calcination and reduction treatment under hydrogen conditions.

[0348] B5. The method according to technical solution B4 is characterized in that, in step (1), the concentration of palladium ions in the active metal precursor solution is 0.05-7% by weight, preferably 0.25-0.50% by weight, and preferably, the impregnation treatment is equal volume impregnation; the impregnation temperature is 20-30℃, and the impregnation time is 10-15h;

[0349] Optionally, the drying conditions include: a drying temperature of 100-120℃ and a drying time of 6-10h;

[0350] Optionally, in step (2), the conditions for the calcination reduction treatment include: a reduction temperature of 300-750℃, preferably 300-620℃; a reduction time of 2-8h, preferably 3-6h; and a hydrogen flow rate of 5-100mL / min, preferably 5-60mL / min.

[0351] B6. The method according to technical solution B1, characterized in that the epichlorohydrin wastewater comes from the reaction of 3-chloropropene and hydrogen peroxide to synthesize epichlorohydrin.

[0352] Optionally, based on the total weight of the epichlorohydrin wastewater, the hydrogen peroxide content is 0.05-3% by weight, preferably 0.1-0.5% by weight.

[0353] B7. The method according to technical solution B6, characterized in that the epichlorohydrin wastewater further includes methanol and water; based on the total weight of the epichlorohydrin wastewater, the methanol content is 20-80% by weight, preferably 40-60% by weight.

[0354] B8. The method according to technical solution B1, characterized in that, in the catalytic hydrogenation reaction, the weight ratio of epichlorohydrin wastewater to hydrogenation catalyst is 100:0.1-7, preferably 100:0.1-1.5.

[0355] B9. The method according to technical solution B1, characterized in that the conditions for the catalytic hydrogenation reaction include: a reaction temperature of 20-50℃, a reaction time of 10-60 min, and a hydrogen pressure of 1-10 bar.

[0356] B10. The method according to technical solution B9 is characterized in that the conditions for the catalytic hydrogenation reaction include: a reaction temperature of 25-45℃, a reaction time of 20-60 min, and a hydrogen pressure of 2-10 bar.

[0357] C1. A method for separating 3-chloropropene and 1-chloropropane, characterized by comprising the following steps:

[0358] (1) Epichlorohydrin containing 3-chloropropene and 1-chloropropane is subjected to a first distillation separation in a first distillation column to obtain a top product containing 3-chloropropene and 1-chloropropane and a bottom product containing epichlorohydrin; wherein, in the epichlorohydrin containing 3-chloropropene and 1-chloropropane, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1;

[0359] (2) Under the action of a catalyst, the top product obtained in step (1) is reacted with hydrogen peroxide; wherein the molar ratio of 3-chloropropene to hydrogen peroxide in the top product is 0.7-0.99:1.

[0360] (3) The reaction product obtained in step (2) is subjected to a second distillation in a second distillation column to obtain a top product rich in 1-chloropropane and a bottom product rich in epichlorohydrin; wherein the mass fraction of 1-chloropropane in the top product is not less than 10% and the mass fraction of 1-chloropropane in the bottom product is not more than 0.1%.

[0361] C2. The method according to technical solution C1, wherein,

[0362] The total mass fraction of 3-chloropropene and 1-chloropropane in the top product obtained in step (1) is not less than 99%;

[0363] Preferably, in the top product obtained in step (1), the mass content of 3-chloropropene is 80-98%, preferably 90-97%; and the mass content of 1-chloropropane is 2-20%, preferably 3-10%.

[0364] Preferably, the conditions for the first distillation separation in step (1) include: a bottom temperature of 81-129°C, a top temperature of 30-60°C, a top pressure of 60-101 kPaA, a theoretical plate number of 10-50, and a top reflux ratio of 1-50.

[0365] C3. The method according to technical solution C1 or C2, wherein,

[0366] In the reaction described in step (2), the conversion rate of 3-chloropropene is not less than 95%, and the conversion rate of 1-chloropropane is not more than 5%.

[0367] Preferably, the reaction temperature of the reaction in step (2) is 10-90℃, more preferably 20-80℃, and even more preferably 30-70℃;

[0368] Preferably, the molar ratio of 3-chloropropene to hydrogen peroxide in the top product of the column is 0.8-0.99:1;

[0369] Preferably, the hydrogen peroxide is provided in the form of an aqueous solution of hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the aqueous solution is not less than 50%, preferably 50-70%;

[0370] Preferably, the mass of the catalyst is 0.1-40% of the total mass of the liquid phase feed, and more preferably 0.5-20%.

[0371] Preferably, the reaction in step (2) is carried out in a fixed-bed reactor.

[0372] C4. The method described according to any one of technical solutions C1-C3, wherein,

[0373] The catalyst in step (2) is a titanium-silicon molecular sieve catalyst. The titanium-silicon molecular sieve catalyst preferably includes titanium-silicon molecular sieve and alumina. Based on the total mass of the titanium-silicon molecular sieve catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, preferably 70-90 wt%; the content of alumina is 5-30 wt%, preferably 10-30 wt%.

[0374] The side-compression crushing strength of the titanium-silicon molecular sieve catalyst is 60-120 N / cm, preferably 60-100 N / cm;

[0375] Preferably, in the titanium-silicon molecular sieve, the mass fraction of titanium, calculated as TiO2, is 1-10%, more preferably 1-5%;

[0376] Preferably, the titanium-silicon molecular sieve is selected from at least one of titanium-silicon molecular sieves having MFI, MEL, BEA, MSE and MWW structures.

[0377] C5. The method described according to technical solution C4, wherein,

[0378] The preparation method of the titanium-silicon molecular sieve catalyst includes: mixing and molding a titanium-silicon molecular sieve precursor containing a template agent, an alumina precursor, and an extrusion aid, and then drying and calcining them.

[0379] The mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor.

[0380] C6. The method described in technical solution C5, wherein,

[0381] The content of the template agent in the titanium-silicon molecular sieve precursor is 1-20 wt%, preferably 1-10 wt%.

[0382] Preferably, the template agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide;

[0383] Preferably, the preparation method of the titanium-silicon molecular sieve precursor containing the template agent includes: mixing a titanium source, a silicon source, a template agent and water, performing hydrothermal crystallization, and then drying;

[0384] Preferably, the method for preparing the titanium-silicon molecular sieve precursor containing the template agent does not include calcining the dried material.

[0385] C7. The method according to technical solution C5 or C6, wherein,

[0386] The mass of the extrusion aid is 5-20% of the dry basis mass of the titanium-silicon molecular sieve precursor;

[0387] Preferably, the calcination conditions include: a temperature of 400-800℃, more preferably 500-600℃; and a time of 2-20h, more preferably 6-12h.

[0388] Preferably, the preparation method of the titanium-silicon molecular sieve catalyst does not include the addition of a pore-forming agent.

[0389] C8. The method described according to any one of technical solutions C1-C7, wherein,

[0390] In step (2), a solvent is also added to the reaction. The solvent is selected from at least one of alcohols with 1-6 carbon atoms, ketones with 3-4 carbon atoms, ethers with 2-10 carbon atoms, nitriles with 2-4 carbon atoms, and carboxylic acid esters with 2-6 carbon atoms.

[0391] Preferably, the molar ratio of solvent to 3-chloropropene is 4-20:1;

[0392] Preferably, an alkaline additive is also added to the reaction in step (2), wherein the alkaline additive is selected from at least one of ammonia, alkaline ammonium salt, organic amine and quaternary ammonium base;

[0393] Preferably, the molar ratio of alkaline additive to hydrogen peroxide is 0.001-0.05:1.

[0394] C9. The method described according to any one of technical solutions C1-C8, wherein,

[0395] Step (3) The conditions for the second distillation separation include: the bottom temperature of the column is 81-119℃, the top temperature of the column is 40-50℃, the top pressure of the column is 60-101kPaA, the theoretical number of plates is 10-50, and the top reflux ratio is 0.5-5.

[0396] C10. The method according to any one of technical solutions C1-C9, wherein,

[0397] In the epichlorohydrin containing 3-chloropropene and 1-chloropropane, the mass fraction of epichlorohydrin is 10-90%, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 90:10-97:3.

[0398] Preferably, the epichlorohydrin containing 3-chloropropene and 1-chloropropane is produced by the hydrogen peroxide process for epichlorohydrin production.

[0399] C11. A method for producing epichlorohydrin, characterized by comprising the following steps:

[0400] S1. In methanol solvent, 3-chloropropene containing 1-chloropropane and hydrogen peroxide are subjected to an epoxidation reaction to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide.

[0401] S2. The solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide is mixed with an extractant and then separated to obtain epichlorohydrin containing 3-chloropropene and 1-chloropropane and a solution containing methanol, water and hydrogen peroxide.

[0402] S3. Separating 3-chloropropene and 1-chloropropane from epichlorohydrin containing 3-chloropropene and 1-chloropropane, wherein the method for separating 3-chloropropene and 1-chloropropane is any one of the methods described in technical solutions C1-C10;

[0403] S4. In a hydrogen atmosphere, the solution containing methanol, water and hydrogen peroxide obtained in S2 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing methanol and water; then the methanol aqueous solution is separated by distillation to obtain methanol.

[0404] In the titanium-silicon molecular sieve catalyst of the present invention, the total content of elements in group 1 (including any one of groups 1.1-1.5 as described below, hereinafter referred to as group 1.x elements), elements in group 2 (including any one of groups 2.1-2.4 as described below, hereinafter referred to as group 2.x elements), elements in group 3 (including any one of groups 3.1-3.4 as described below, hereinafter referred to as group 3.x elements), elements in group 4 (including any one of groups 4.1-4.4 as described below, hereinafter referred to as group 4.x elements), and elements in group 5 (including any one of groups 5.1-5.19 as described below, hereinafter referred to as group 5.x elements) can be less than 20 wt% or less than 19 wt%. %, or less than 18wt%, or less than 17wt%, or less than 16wt%, or less than 15wt%, or less than 14wt%, or less than 13wt%, or less than 12wt%, or less than 11wt%, or less than 10wt%, or less than 9wt%, or less than 8wt%, or less than 7wt%, or less than 6wt%, or less than 5wt%, or less than 4wt%, or less than 3wt%, or less than 2wt%, or less than 1wt%, or less than 0.5wt%, or less than 0.4wt%, or less than 0.3wt%, or less than 0.2wt%, or less than 0.1wt%, or less than 0.05wt%, or less than 0.01wt%, or less than 0.005wt%; and / or

[0405] In the titanium-silicon molecular sieve catalyst of the present invention, the content of the first group of elements (including the first x group of elements) may be less than 20 wt%, or less than 19 wt%, or less than 18 wt%, or less than 17 wt%, or less than 16 wt%, or less than 15 wt%, or less than 14 wt%, or less than 13 wt%, or less than 12 wt%, or less than 11 wt%, or less than 10 wt%, or less than 9 wt%, or less than 8 wt%, or less than 7 wt%, or less than 6 wt%, or less than 5 wt%, or less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, or less than 0.4 wt%, or less than 0.3 wt%, or less than 0.2 wt%, or less than 0.1 wt%, or less than 0.05 wt%, or less than 0.01 wt%, or less than 0.005 wt%; and / or;

[0406] In the titanium-silicon molecular sieve catalyst of the present invention, the content of the second group of elements (including the second.x group of elements) may be less than 20 wt%, or less than 19 wt%, or less than 18 wt%, or less than 17 wt%, or less than 16 wt%, or less than 15 wt%, or less than 14 wt%, or less than 13 wt%, or less than 12 wt%, or less than 11 wt%, or less than 10 wt%, or less than 9 wt%, or less than 8 wt%, or less than 7 wt%, or less than 6 wt%, or less than 5 wt%, or less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, or less than 0.4 wt%, or less than 0.3 wt%, or less than 0.2 wt%, or less than 0.1 wt%, or less than 0.05 wt%, or less than 0.01 wt%, or less than 0.005 wt%; and / or;

[0407] In the titanium-silicon molecular sieve catalyst of the present invention, the content of the third group of elements (including the third.x group of elements) may be less than 20 wt%, or less than 19 wt%, or less than 18 wt%, or less than 17 wt%, or less than 16 wt%, or less than 15 wt%, or less than 14 wt%, or less than 13 wt%, or less than 12 wt%, or less than 11 wt%, or less than 10 wt%, or less than 9 wt%, or less than 8 wt%, or less than 7 wt%, or less than 6 wt%, or less than 5 wt%, or less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, or less than 0.4 wt%, or less than 0.3 wt%, or less than 0.2 wt%, or less than 0.1 wt%, or less than 0.05 wt%, or less than 0.01 wt%, or less than 0.005 wt%; and / or;

[0408] In the titanium-silicon molecular sieve catalyst of the present invention, the content of the fourth group of elements (including the fourth x group of elements) may be less than 20 wt%, or less than 19 wt%, or less than 18 wt%, or less than 17 wt%, or less than 16 wt%, or less than 15 wt%, or less than 14 wt%, or less than 13 wt%, or less than 12 wt%, or less than 11 wt%, or less than 10 wt%, or less than 9 wt%, or less than 8 wt%, or less than 7 wt%, or less than 6 wt%, or less than 5 wt%, or less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, or less than 0.4 wt%, or less than 0.3 wt%, or less than 0.2 wt%, or less than 0.1 wt%, or less than 0.05 wt%, or less than 0.01 wt%, or less than 0.005 wt%; and / or;

[0409] In the titanium-silicon molecular sieve catalyst of the present invention, the content of the fifth group of elements (including the fifth x group of elements) may be less than 20 wt%, or less than 19 wt%, or less than 18 wt%, or less than 17 wt%, or less than 16 wt%, or less than 15 wt%, or less than 14 wt%, or less than 13 wt%, or less than 12 wt%, or less than 11 wt%, or less than 10 wt%, or less than 9 wt%, or less than 8 wt%, or less than 7 wt%, or less than 6 wt%, or less than 5 wt%, or less than 4 wt%, or less than 3 wt%, or less than 2 wt%, or less than 1 wt%, or less than 0.5 wt%, or less than 0.4 wt%, or less than 0.3 wt%, or less than 0.2 wt%, or less than 0.1 wt%, or less than 0.05 wt%, or less than 0.01 wt%, or less than 0.005 wt%; and / or;

[0410] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the first group of elements (including the first x group of elements) to silicon can be less than 0.01, for example less than 0.001, or less than 0.0001, or less than 0.00001, or less than 0.000001; and / or

[0411] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the second group of elements (including the second.x group of elements) to silicon can be less than 0.01, for example less than 0.001, or less than 0.0001, or less than 0.00001, or less than 0.000001; and / or

[0412] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the third group element (including the third x group element) to silicon can be less than 0.01, for example less than 0.001, or less than 0.0001, or less than 0.00001, or less than 0.000001; and / or

[0413] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the fourth group element (including the fourth x group element) to silicon can be less than 0.01, for example less than 0.001, or less than 0.0001, or less than 0.00001, or less than 0.000001; and / or

[0414] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the fifth group element (including the fifth x group elements) to silicon can be less than 0.01, for example less than 0.001, or less than 0.0001, or less than 0.00001, or less than 0.000001; and / or

[0415] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the first group of elements (including the first x group of elements) to titanium can be less than 0.5, for example less than 0.05, or less than 0.005, or less than 0.0005, or less than 0.00005; and / or

[0416] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the second group of elements (including the second.x group of elements) to titanium can be less than 0.5, for example less than 0.05, or less than 0.005, or less than 0.0005, or less than 0.00005; and / or

[0417] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the third group element (including the third.x group element) to titanium can be less than 0.5, for example less than 0.05, or less than 0.005, or less than 0.0005, or less than 0.00005; and / or

[0418] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the fourth group element (including the fourth x group element) to titanium can be less than 0.5, for example less than 0.05, or less than 0.005, or less than 0.0005, or less than 0.00005; and / or

[0419] In the titanium-silicon molecular sieve catalyst of the present invention, the molar ratio of the fifth group element (including the fifth x group element) to the titanium element can be less than 0.5, for example less than 0.05, or less than 0.005, or less than 0.0005, or less than 0.00005.

[0420] in

[0421] The first group of elements (rare earth metals) is selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0422] in,

[0423] The elements in group 1.1 are selected from Ce, La, Y, Sm, Gd, Yb, and Lu;

[0424] The elements in group 1.2 are selected from Ce and La;

[0425] The elements in group 1.3 are selected from Ce;

[0426] The elements in group 1.4 are selected from La;

[0427] The elements in group 1.5 are selected from Y, Sm, Gd, Yb, and Lu;

[0428] The second group of elements (alkali metals) is selected from Li, Na, K, Rb, and Cs;

[0429] in,

[0430] The elements in group 2.1 are selected from K and Cs;

[0431] The elements in group 2.2 are selected from K;

[0432] The elements in group 2 and 3 are selected from Cs;

[0433] The elements in group 2.4 are selected from Na;

[0434] The third group of elements (alkaline earth metals) is selected from Be, Mg, Ca, Sr, and Ba;

[0435] in,

[0436] The elements in group 3.1 are selected from Mg and Ca;

[0437] The elements in group 3.2 are selected from Mg;

[0438] The elements in group 3.3 are selected from Ca;

[0439] The elements in group 3.4 are selected from Sr and Ba;

[0440] The fourth group of elements (precious metals) is selected from Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au;

[0441] in,

[0442] The elements in group 4.1 are selected from Pd and Au;

[0443] The elements in group 4.2 are selected from Pd;

[0444] The elements in group 4.3 are selected from Au;

[0445] The elements in group 4.4 are selected from Pt and Ag;

[0446] The fifth group of elements (others) is selected from: Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Cd, In, Hf, Ta, W, Re, Tl, Sn, Pb;

[0447] in,

[0448] Group 5.1 elements are selected from Cu, Fe, Sn, Zr, Cr, Mn, Ni, Zn, Mo, V, Co, Ga, Nb, Hf, W, and Y;

[0449] The elements in group 5.2 are selected from Cu;

[0450] The elements in group 5.3 are selected from Fe;

[0451] The elements in group 5.4 are selected from Sn;

[0452] The elements in group 5.5 are selected from Zr;

[0453] The elements in group 5 and 6 are selected from Cu and Fe;

[0454] The elements in group 5.7 are selected from Sn and Zr;

[0455] The elements in group 5.8 are selected from Cr, Mn, Ni, Zn, and Mo;

[0456] The elements in group 5.9 are selected from V, Co, Ga, Nb, Hf, W, and Y;

[0457] The elements in group 5.10 are selected from Cu, Fe, Sn, and Zr;

[0458] The elements in group 5.11 are selected from Cu, Fe, Cr, Mn, Ni, Zn, and Mo;

[0459] The elements in group 5.12 are selected from Cu, Fe, V, Co, Ga, Nb, Hf, W, and Y;

[0460] The elements in group 5.13 are selected from Sn, Zr, Cr, Mn, Ni, Zn, and Mo;

[0461] The elements in group 5.14 are selected from Sn, Zr, V, Co, Ga, Nb, Hf, W, and Y;

[0462] The elements in group 5.15 are selected from Cr, Mn, Ni, Zn, Mo, V, Co, Ga, Nb, Hf, W, and Y;

[0463] The elements in group 5.16 are selected from Cu, Fe, Sn, Zr, Cr, Mn, Ni, Zn, and Mo;

[0464] The elements in group 5.17 are selected from Cu, Fe, Sn, Zr, V, Co, Ga, Nb, Hf, W, and Y;

[0465] The elements in group 5.18 are selected from Cu, Fe, Cr, Mn, Ni, Zn, Mo, V, Co, Ga, Nb, Hf, W, and Y;

[0466] Group 5.19 elements are selected from Sn, Zr, Cr, Mn, Ni, Zn, Mo, V, Co, Ga, Nb, Hf, W, and Y.

[0467] Example

[0468] The technical solution of the present invention will be further described in detail below through embodiments.

[0469] The content of each component in the catalyst described in this invention can be obtained by X-ray fluorescence spectroscopy.

[0470] The elemental content in catalysts can also be determined using analytical methods known in the field, such as those described in "Analytical Methods in Petrochemical Industry (RIPP Test Methods)" (Yang Cuiding, Science Press, 1990), specifically including but not limited to: colorimetric methods (RIPP35-90, RIPP36-90, RIPP37-90, RIPP38-90); atomic absorption spectrometry (such as RIPP114-90, RIPP115-90, RIPP116-90, RIPP117-90, RIPP118-90). RIPP119-90, RIPP120-90, RIPP121-90, RIPP122-90, RIPP123-90); Inductively Coupled Plasma Emission Spectroscopy (ICP / AES) (e.g., RIPP126-90, RIPP127-90, RIPP128-90, RIPP129-90); X-ray Fluorescence Spectroscopy (e.g., RIPP131-90, RIPP132-90, RIPP133-90, RIPP134-90, RIPP135-90).

[0471] The alumina content in the catalyst can also be determined according to analytical methods known in the field, such as "Analytical Methods for Petrochemical Products (RIPP Test Method)" (Yang Cuiding, Science Press, 1990), specifically including but not limited to: RIPP 41-90 and RIPP 42-90.

[0472] The content of titanium-silicon molecular sieve in the catalyst can also be determined by the following methods: (1) the crystal type of titanium-silicon molecular sieve in the catalyst is determined by XRD; (2) pure titanium-silicon molecular sieve of the same crystal type is prepared as a standard sample; (3) XRD tests are performed on the standard sample and the catalyst sample to be tested with the same mass; (4) one or more characteristic diffraction peaks are selected (for example, for TS-1 titanium-silicon molecular sieve, the main peak with 2θ around 23° is selected), the peak areas of the sample to be tested and the standard sample are measured and the ratio of the two is calculated to obtain the content of titanium-silicon molecular sieve in the catalyst. XRD is measured on a Siemens D5005 X-ray diffractometer, the X-ray source is Kα (Cu), and the test range is 2θ in the range of 0.5-70°.

[0473] The test process for the lateral crushing strength of the catalyst described in this invention includes: using a ZQJ-II intelligent particle strength tester manufactured by Dalian Intelligent Testing Machine Factory, referring to the HG / T2782-2024 standard, and the measured lateral crushing strength is the average value of 20 particles.

[0474] The specific surface area and pore volume of aluminum hydroxide powder were measured by BET.

[0475] The precursor powder of titanium-silicon molecular sieve containing template agent is obtained after the hydrothermal crystallization step when preparing titanium-silicon molecular sieves using the hydrothermal synthesis method. It is a titanium-silicon molecular sieve precursor that has not yet been calcined to remove the template agent and is produced by Hunan Jianchang Petrochemical Co., Ltd.

[0476] All raw materials used in the embodiments can be obtained through commercial purchase.

[0477] The content of active metal components in the catalyst was obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0478] The total specific surface area, micropore specific surface area, and structural characteristics of the catalyst were obtained by static capacity adsorption analysis. The particle size of the catalyst was controlled by grinding and sieving.

[0479] Hydrogen peroxide conversion rate = (hydrogen peroxide content in feed - hydrogen peroxide content in discharge) / hydrogen peroxide content in feed × 100%; where

[0480] In the treatment of epichlorohydrin synthesis wastewater, after the hydrogen peroxide hydrogenation reaction is completed, the concentration of hydrogen peroxide in the epichlorohydrin wastewater before and after the reaction can be analyzed using a hydrogen peroxide titrator (Metroën, Switzerland). This allows for the calculation of the hydrogen peroxide conversion rate.

[0481] The concentration of hydrogen peroxide in the reaction sample was determined by indirect iodometric titration.

[0482] The operating steps are as follows: Add 15 mL of 20% (w / w) dilute sulfuric acid solution to a 100 mL beaker. Add a certain amount of sample to the beaker, along with 1 g of potassium iodide reagent. Add 4-5 drops of 3 wt% ammonium molybdate solution to the beaker, then seal it with plastic wrap and place it in the dark for 10 minutes. After removing the sample, add a certain amount of deionized water to the beaker until the liquid volume reaches approximately 60 mL. Titrate the reaction product using a 0.1 mol / L sodium thiosulfate standard solution in an automatic potentiometric titrator. Perform three parallel experiments and a blank experiment for each reaction sample. The formula for calculating the hydrogen peroxide concentration in the mixed sample is:

[0483] V1: Volume (mL) of sodium thiosulfate standard solution consumed in titrating the sample to be tested;

[0484] V2: Volume (mL) of sodium thiosulfate standard solution consumed in titrating the blank sample;

[0485] C Na2S2O3 The accurate concentration (mol / L) of the sodium thiosulfate standard solution;

[0486] m: Mass of the added sample.

[0487] The product composition was analyzed using an Agilent GC-6890N gas chromatograph under the following conditions: a 30m × 0.32mm × 0.25μm Agilent DB-WAX column was used, with nitrogen as the carrier gas at a flow rate of 25ml / min; hydrogen was used as the fuel gas at a flow rate of 40ml / min; and air was used as the auxiliary combustion gas at a flow rate of 300ml / min. The column inlet pressure was 85kPa; the column temperature was set from 50℃ to 220℃ (50℃ held for 2min, then increased to 220℃ at a rate of 10℃ / min, with a total monitoring time of 22min); the injection port and flame ionization detector (FID) temperatures were both set to 250℃.

[0488] 3-Chloropropene conversion rate = (3-chloropropene content in feed - 3-chloropropene content in discharge) / 3-chloropropene content in feed × 100%.

[0489] Epichlorohydrin selectivity = Epichlorohydrin content in the discharge / Epichlorohydrin and its ring-opening byproduct content in the discharge × 100%.

[0490] The following example illustrates the synthesis process of epichlorohydrin according to the present invention.

[0491] (I) Preparation of Titanium-Silicon Molecular Sieve Catalysts

[0492] Preparation Example 1

[0493] 239.7 grams of titanium-silicon molecular sieve precursor powder containing 5% tetrapropylammonium hydroxide template agent (based on the dry basis of the titanium-silicon molecular sieve precursor powder, calculated as TiO2, with a titanium mass fraction of 5%) and 59 grams of aluminum hydroxide powder (alumina content 70.1 wt%, BET specific surface area 347 m²) were mixed. 2 35.7 g of starch and 8 g of guar gum powder (total mass of starch and guar gum powder is 19.2% of the dry basis mass of the titanium silicate molecular sieve precursor) were mixed in a small kneader for 30 min; then 223.2 g of acidic aluminum sol (pH 3.6) with a solid content of 23.8 wt% and 33 g of deionized water were added sequentially, and mixing continued for 60 min; then the mixture was passed through a twin-screw extruder. The perforated plates were extruded into strip-shaped catalyst precursors, which were then dried at room temperature for 24 hours and cut into short strips of about 5 mm. These strips were then placed in a muffle furnace and heated from room temperature to 120°C at a heating rate of 5°C / min and held for 3 hours. Subsequently, they were heated to 550°C at a heating rate of 3°C / min and held for 6 hours to obtain catalyst A1. The catalyst composition and characteristic parameters are shown in Table 1.

[0494] Preparation Example 2

[0495] 273.9 g of titanium-silicon molecular sieve precursor powder containing 8% tetrapropylammonium hydroxide template agent (based on the dry basis of the titanium-silicon molecular sieve precursor powder, with a titanium content of 5% as TiO2) and 17.9 g of aluminum hydroxide powder (alumina content of 70.1 wt%, BET specific surface area of ​​347 m²) were mixed. 2 31.5 g of starch and 8 g of guar gum powder (total mass of starch and guar gum powder is 15.7% of the dry basis mass of the titanium silicate molecular sieve precursor) were mixed in a small kneader for 30 min; then 212.2 g of acidic aluminum sol (pH 3.6) with a solid content of 23.8 wt% and 25 g of deionized water were added sequentially, and mixing continued for 60 min; then the mixture was passed through a twin-screw extruder. The perforated plates were extruded into strip-shaped catalyst precursors, which were then dried at room temperature for 24 hours and cut into short strips of about 5 mm. These strips were then placed in a muffle furnace and heated from room temperature to 120°C at a heating rate of 5°C / min and held for 3 hours. Subsequently, they were heated to 570°C at a heating rate of 3°C / min and held for 6 hours to obtain catalyst A2. The catalyst composition and characteristic parameters are shown in Table 1.

[0496] Preparation Example 3

[0497] 297.9 g of titanium silicate molecular sieve precursor powder containing 8% tetrapropylammonium hydroxide template agent (based on the dry basis of the titanium silicate molecular sieve precursor powder, with a titanium content of 5% as TiO2), 25.2 g of starch, and 6.3 g of guar gum powder (the total mass of starch and guar gum powder is 11.5% of the dry basis of the titanium silicate molecular sieve precursor) were mixed in a small kneader for 30 min; then 172.4 g of acidic aluminum sol (pH 3.6) with a solid content of 23.8 wt% and 20 g of deionized water were added sequentially, and mixing continued for 60 min; then the mixture was passed through a twin-screw extruder. The perforated plates were extruded into strip-shaped catalyst precursors, which were then dried at room temperature for 24 hours and cut into short strips of about 5 mm. These strips were then placed in a muffle furnace and heated from room temperature to 120°C at a heating rate of 5°C / min and held for 3 hours. Subsequently, they were heated to 570°C at a heating rate of 3°C / min and held for 6 hours to obtain catalyst A3. The catalyst composition and characteristic parameters are shown in Table 1.

[0498] Preparation Example 4

[0499] 10.3 kg of titanium-silicon molecular sieve precursor powder containing 8% tetrapropylammonium hydroxide template agent (based on the dry basis of the titanium-silicon molecular sieve precursor powder, with a titanium content of 5% as TiO2) and 1.6 kg of aluminum hydroxide powder (alumina content of 70.1 wt%, BET specific surface area of ​​410 m²) were mixed. 2 1.3 kg of starch and 0.3 kg of guar gum powder (total mass of starch and guar gum powder is 16.9% of the mass of the titanium silicate molecular sieve) were mixed in a medium-sized high-intensity mixer for 30 min; then 8.5 kg of acidic aluminum sol with a solid content of 23.7% (pH 2.8) and 1.0 kg of deionized water were added sequentially, and mixing continued for 60 min; then the mixture was passed through a twin-screw extruder. The perforated plates were extruded into strip-shaped catalyst precursors, which were then dried at room temperature for 24 hours and cut into short strips of about 5 mm. These strips were then placed in a shuttle kiln and heated from room temperature to 120°C at a heating rate of 5°C / min and held for 3 hours. Subsequently, they were heated to 570°C at a heating rate of 3°C / min and held for 6 hours to obtain catalyst A4. The catalyst composition and characteristic parameters are shown in Table 1.

[0500] Preparation of Comparative Example 1

[0501] Titanium-silicon molecular sieve catalyst B1 was synthesized according to the method of patent application CN201010184391.9.

[0502] 210 g of HTS titanium-silicon molecular sieve (calculated as TiO2, titanium mass fraction is 5%) and 109.4 g of aluminum hydroxide powder (alumina content 74.2 wt%, BET specific surface area 445 m²) were added. 2 78.8 g of starch and 8.8 g of guar gum powder were mixed in a kneader for 60 min; then 263.0 g of aluminum sol with an alumina content of 22.4%, 17.50 g of octylphenol polyoxyethylene (15) ether (OP-15), and 21 g of deionized water were added sequentially and kneaded into a dough. The total mass of starch, guar gum powder, and OP-15 in the dough was 50% of the mass of the HTS raw powder. Kneading was continued for 120 min; then the dough was extruded through a twin-screw extruder. The perforated plate was extruded into wet, slender, solid cylindrical strips, which were then dried at room temperature for 24 hours and placed in a box-type resistance furnace. The furnace was heated from room temperature to 120°C at a heating rate of 3°C / min and held for 2 hours, then heated to 270°C at a heating rate of 5°C / min and held for 1 hour, and finally heated to 560°C at a heating rate of 4°C / min and held for 24 hours to obtain catalyst B1. The catalyst composition and characteristic parameters are shown in Table 1.

[0503] Preparation of Comparative Example 2

[0504] 245 g of HTS titanium-silicon molecular sieve (calculated as TiO2, titanium mass fraction is 5%) and 62.1 g of aluminum hydroxide powder (alumina content 74.2 wt%, BET specific surface area 445 m²) were added. 2 78.8 g of starch and 8.8 g of guar gum powder were mixed in a kneader for 60 min; then 263.0 g of aluminum sol with an alumina content of 22.4%, 17.50 g of octylphenol polyoxyethylene (15) ether (OP-15), and 21 g of deionized water were added sequentially and kneaded into a dough. The total mass of starch, guar gum powder, and OP-15 in the dough was 50% of the mass of the HTS raw powder. Kneading was continued for 120 min; then the dough was extruded through a twin-screw extruder. The perforated plate was extruded into wet, slender, solid cylindrical strips, which were then dried at room temperature for 24 hours and placed in a box-type resistance furnace. The furnace was heated from room temperature to 120°C at a heating rate of 3°C / min and held for 2 hours, then heated to 270°C at a heating rate of 5°C / min and held for 1 hour, followed by heating to 560°C at a heating rate of 4°C / min and held for 24 hours to obtain catalyst B2. The catalyst composition and characteristic parameters are shown in Table 1.

[0505] Table 1

[0506] As can be seen from the results in Table 1, the catalyst described in this invention has both good mechanical strength and high titanium-silicon molecular sieve content, which significantly improves the catalyst's catalytic activity and service life.

[0507] (II) Synthesis of Epichlorohydrin

[0508] Synthesis Example 1

[0509] In a water bath reactor, 3-chloropropene, 30 wt% hydrogen peroxide aqueous solution (3-chloropropene to hydrogen peroxide molar ratio of 2.5:1), methanol (methanol to hydrogen peroxide molar ratio of 5:1), the titanium-silicon molecular sieve catalyst obtained in the preparation examples or comparative examples (3 wt% of the total mass of the above reaction solution), and 28 wt% ammonia water (0.02 wt% of the total mass of the above reaction solution) were added. After sealing the reactor, nitrogen gas was introduced until the pressure reached 0.4 MPa, and the stirring speed was 300 rpm. The water bath temperature was set to 50℃, and the reaction time was 30 min. After the reaction was stopped, the reactor was cooled uniformly by circulating cold water bath at 15℃. The clear liquid was taken for titration analysis and gas chromatography analysis. The results are shown in Table 2.

[0510] It should be noted that the reaction solution here refers to a mixture of solvent, 3-chloropropene, and aqueous hydrogen peroxide solution.

[0511] Table 2

[0512] As can be seen from the results in Table 2, the titanium-silicon molecular sieve catalyst provided by the present invention exhibits high initial activity in the reaction of 3-chloropropene epoxidation to prepare epichlorohydrin, with a hydrogen peroxide conversion rate of over 96% and an epichlorohydrin selectivity of over 97%.

[0513] Synthesis Example 2

[0514] 50g of the titanium-silicon molecular sieve catalyst prepared in Example 1 or Comparative Example 1 was loaded into a tubular fixed-bed reactor. The reaction tube jacket oil bath temperature was 50°C, the reaction pressure was 0.4MPa, the feed molar ratio of 3-chloropropene to hydrogen peroxide was 2.5:1, the feed molar ratio of methanol to hydrogen peroxide was 5:1, and the feed mass hourly space velocity of the hydrogen peroxide aqueous solution (30wt%) was 0.17h. -1 The reaction was carried out under the specified conditions. During the epoxidation reaction, 0.01% (by mass) of ammonium hydroxide was added to the reaction feed. The evaluation results of the catalyst prepared in Example 1 are shown in Table 3, and the evaluation results of the catalyst prepared in Comparative Example 1 are shown in Table 4.

[0515] Table 3

[0516] Table 4

[0517] As can be seen from the results in Tables 3 and 4, the titanium-silicon molecular sieve catalyst provided in Example 1 maintained a hydrogen peroxide conversion rate of over 99% after 400 hours of reaction in a fixed-bed reactor; while the titanium-silicon molecular sieve catalyst in Comparative Example 1 only required 205 hours of reaction in a fixed-bed reactor before its hydrogen peroxide conversion rate dropped to 98.1%. This demonstrates that the titanium-silicon molecular sieve catalyst provided by this invention has higher stability and a significantly longer service life.

[0518] (III) Examples and Comparative Examples of Hydrogenation Catalyst Preparation

[0519] Preparation Example A1

[0520] This embodiment is used to prepare a hydrogenation catalyst (Pd / C catalyst, denoted as C1), an activated carbon support, and an active metal component; the active metal component includes Pd, and based on the total weight of the hydrogenation catalyst, the content of the active metal component Pd is 0.5% by weight. The specific steps include:

[0521] First, the water absorption capacity of 1 gram of activated carbon was measured to be 2 grams. Then, 2.0084 grams of PdCl2 aqueous solution (active metal precursor solution, palladium ion concentration of 0.25 wt%) and 1 gram of activated carbon were used to prepare a catalyst precursor by an equal-volume impregnation method. The impregnation temperature was 25℃ and the impregnation time was 12 h. After drying the catalyst precursor, it was calcined and reduced in a hydrogen atmosphere to obtain the catalyst. The drying temperature was 120℃ and the drying time was 6 h. The calcination and reduction temperature was 500℃ and the calcination and reduction time was 4 h. The hydrogen flow rate was 40 mL / min.

[0522] The obtained catalyst C1 has a mesh size of 80 mesh and a total specific surface area of ​​1708 m². 2 / g, of which the microporous specific surface area accounts for 95.0%.

[0523] Preparation Example A2

[0524] This embodiment is used to prepare a hydrogenation catalyst (Pd / C catalyst, denoted as C2), an activated carbon support, and an active metal component; the active metal component includes Pd, and the content of Pd in ​​the active metal component is 1% by weight based on the total weight of the hydrogenation catalyst.

[0525] This embodiment refers to the method in preparation embodiment A1, but differs from preparation embodiment A1 in that:

[0526] A catalyst precursor was prepared by impregnation of 2.0168 g of PdCl2 aqueous solution (active metal precursor solution, palladium ion concentration of 0.50 wt%) and 1 g of activated carbon in equal amounts. The remaining process was the same as in Preparation Example A1.

[0527] Preparation Example A3

[0528] This example is used to prepare a hydrogenation catalyst (Pd / C catalyst, denoted as C3), which differs from the preparation example A1 in that:

[0529] The catalyst mesh size was adjusted to 100 mesh, and the rest of the process was the same as in Preparation Example A1.

[0530] Preparation Example A4

[0531] This example is used to prepare a hydrogenation catalyst (Pd / C catalyst, denoted as C4), which differs from the preparation example A1 in that:

[0532] The catalyst mesh size was adjusted to 30 mesh, and the rest of the process was the same as in Preparation Example A1.

[0533] Preparation Example A5

[0534] This embodiment refers to the preparation method in preparation 1, but differs from preparation embodiment A1 in that:

[0535] The activated carbon carrier was replaced, and the specific surface area of ​​the new activated carbon carrier is 1190 m². 2 / g, of which the microporous specific surface area accounts for 93.2%; the equivalent water absorption of 1 gram of activated carbon is 1.8 grams; then 1.8084 grams of PdCl2 aqueous solution (active metal precursor solution, palladium ion concentration of 0.28 wt%) and activated carbon (1 gram) are used to prepare the catalyst precursor by an equal volume impregnation method; the rest of the process is the same as in preparation example A1, and the hydrogenation catalyst C5 is prepared.

[0536] Preparation Example A6

[0537] This embodiment refers to the preparation method in preparation 1, but differs from preparation embodiment A1 in that:

[0538] The activated carbon carrier was replaced, and the specific surface area of ​​the new activated carbon carrier is 1852 m². 2 / g, wherein the microporous specific surface area ratio is 73.3%; the equivalent water absorption of 1 gram of activated carbon is 2.3 grams; then 2.3084 grams of PdCl2 aqueous solution (active metal precursor solution, palladium ion concentration is 0.22 wt%) and activated carbon (1 gram) are used to prepare the catalyst precursor by an equal volume impregnation method; the remaining process is the same as in preparation example A1, and the hydrogenation catalyst C6 is prepared.

[0539] Preparation Example A7

[0540] This embodiment is used to prepare a hydrogenation catalyst (Pd / C catalyst, denoted as C7), an activated carbon support, and an active metal component; the active metal component includes Pd, and the content of Pd in ​​the active metal component is 0.1% by weight based on the total weight of the hydrogenation catalyst.

[0541] This embodiment refers to the method in preparation embodiment A1, but differs from preparation embodiment A1 in that:

[0542] A catalyst precursor was prepared by impregnation of 2.0017 g of PdCl2 aqueous solution (active metal precursor solution, palladium ion concentration of 0.05 wt%) and 1 g of activated carbon in equal amounts. The remaining process was the same as in Preparation Example A1.

[0543] Preparation Example A8

[0544] This embodiment is used to prepare a hydrogenation catalyst (Pd / C catalyst, denoted as C8), an activated carbon support, and an active metal component; the active metal component includes Pd, and the content of Pd in ​​the active metal component is 2% by weight based on the total weight of the hydrogenation catalyst.

[0545] This embodiment refers to the method in preparation embodiment A1, but differs from preparation embodiment A1 in that:

[0546] A catalyst precursor was prepared by impregnation of 2.0340 g of PdCl2 aqueous solution (active metal precursor solution, palladium ion concentration of 1.0 wt%) and 1 g of activated carbon by an equal volume method. The remaining process was the same as in Preparation Example A1.

[0547] Preparation Example A9

[0548] In this embodiment, hydrogenation catalyst C9 was prepared according to the preparation method in preparation embodiment A1.

[0549] The difference from preparation example A1 is that:

[0550] The calcination reduction temperature was 750℃, the calcination reduction time was 2 hours, and the hydrogen flow rate was 100 mL / min.

[0551] Preparation of Comparative Example A1

[0552] This comparative example was used to prepare a hydrogenation catalyst (Pt / C catalyst, denoted as D1), an activated carbon support, and an active metal component; the active metal component included Pt, and the content of Pt in the active metal component was 0.5% by weight, based on the total weight of the hydrogenation catalyst.

[0553] This comparative example follows the method in preparation example A1, but differs from preparation example A1 in the following aspects:

[0554] A catalyst precursor was prepared by impregnation of 2.0106 g of H2PtCl6 aqueous solution (active metal precursor solution, platinum ion concentration of 0.25 wt%) and 1 g of activated carbon by an equal volume method. The remaining process was the same as in Preparation Example A1.

[0555] Preparation of Comparative Example A2

[0556] This comparative example was used to prepare a hydrogenation catalyst (Ru / C catalyst, denoted as D2), an activated carbon support, and an active metal component; the active metal component included Ru, and the content of the active metal component Ru was 0.5% by weight based on the total weight of the hydrogenation catalyst.

[0557] This comparative example follows the method in preparation example A1, but differs from preparation example A1 in the following aspects:

[0558] A catalyst precursor was prepared by impregnation of 2.0103 g of RuCl3 aqueous solution (active metal precursor solution with ruthenium ion concentration of 0.25 wt%) and 1 g of activated carbon by an equal volume impregnation method. The remaining process was the same as in Preparation Example A1.

[0559] The active metal content and structural characteristic parameters of the catalysts obtained from the above preparation examples and comparative examples are listed in Table 5 below.

[0560] Table 5

[0561] The catalyst mesh sizes in Table 5 are obtained by sieving the catalyst particles using 30-mesh, 80-mesh, or 100-mesh sieves.

[0562] (iv) Treatment of epichlorohydrin synthesis wastewater

[0563] The following examples illustrate the catalytic effect of the hydrogenation catalyst prepared above in the reaction for removing hydrogen peroxide from epichlorohydrin wastewater. Epichlorohydrin wastewater consists of methanol, water, and hydrogen peroxide, wherein the methanol concentration is 50% by weight and the hydrogen peroxide concentration is 0.5% by weight (5000 ppm).

[0564] Example A1

[0565] 50 g of epoxidized wastewater was added to a 100 mL Hastelloy reactor. 0.05 g of catalyst C1 from Preparation Example A1 was added. The weight ratio of epichlorohydrin wastewater to hydrogenation catalyst was 100:0.1. The catalytic hydrogenation reaction was carried out under a hydrogen atmosphere. The conditions for the catalytic hydrogenation reaction were: hydrogen pressure of 2 bar, reaction temperature of 30 °C, reaction time of 60 min, and rotation speed of 500 r / min. After the reaction was completed, the hydrogen pressure was reduced to 0.5 bar, and then the catalyst was filtered. The resulting reaction solution was titrated to determine the hydrogen peroxide concentration, and the hydrogen peroxide conversion rate was calculated, as shown in Table 6.

[0566] Example A2

[0567] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0568] The amount of catalyst C1 added was adjusted to 0.1 g, the weight ratio of epichlorohydrin wastewater to hydrogenation catalyst was 100:0.2, the reaction time was adjusted to 40 min, and the rest of the process was the same as in Example A1; the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0569] Example A3

[0570] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0571] The reaction temperature was adjusted to 50°C and the reaction time was adjusted to 30 min; the rest of the process was the same as in Example A1; the hydrogen peroxide concentration was measured after the reaction and the hydrogen peroxide conversion rate was calculated, as shown in Table 6.

[0572] Example A4

[0573] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0574] The catalyst C1 was replaced with the catalyst C2 prepared in Example A2, and the hydrogenation catalytic reaction time was adjusted to 35 min; the rest of the process was the same as in Example A1; the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0575] Example A5

[0576] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0577] The catalyst C1 was replaced with the catalyst C3 prepared in Example A3, and the rest of the process was the same as in Example A1. The hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0578] Example A6

[0579] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0580] Catalyst C1 was replaced with catalyst C4 prepared in Preparation Example A4, and the amount of catalyst added was adjusted to 0.5g. The weight ratio of epichlorohydrin wastewater to hydrogenation catalyst was 100:1. The rest of the process was the same as in Example A1. The hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0581] Example A7

[0582] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0583] The catalyst C1 was replaced with the catalyst C4 prepared in Example A4, and the hydrogen pressure was increased to 10 bar. The rest of the process was the same as in Example A1. After the reaction, the hydrogen pressure was measured to decrease to 8.5 bar. The hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0584] Example A8

[0585] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0586] The catalyst C1 was replaced with the catalyst C5 prepared in Example A5, and the rest of the process was the same as in Example A1; the hydrogen pressure dropped to 0.8 bar after the reaction; the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0587] Example A9

[0588] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0589] The catalyst C1 was replaced with the catalyst C6 prepared in Example A6, and the rest of the process was the same as in Example A1. After the reaction, the hydrogen pressure dropped to 1.3 bar, the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0590] Example A10

[0591] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0592] The catalyst C1 was replaced with the catalyst C7 prepared in Example A7, and the rest of the process was the same as in Example A1; the hydrogen pressure dropped to 1.1 bar after the reaction; the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0593] Example A11

[0594] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0595] The catalyst C1 was replaced with the catalyst C8 prepared in Example A8, the reaction time was adjusted to 25 min, and the rest of the process was the same as in Example A1; the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0596] Example A12

[0597] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0598] The catalyst C1 was replaced with the catalyst C9 prepared in Example A9, and the rest of the process was the same as in Example A1; the hydrogen pressure dropped to 0.9 bar after the reaction; the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0599] Example A13

[0600] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0601] 1g of catalyst C1 from Example A1 was added to 50g of epoxidized wastewater. The weight ratio of epichlorohydrin wastewater to hydrogenation catalyst was 100:2, and the rest of the process was the same as in Example A1. After the reaction, the hydrogen pressure dropped to 0.7 bar, the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0602] Example A14

[0603] This embodiment refers to the method in embodiment A1, but differs from embodiment A1 in that:

[0604] The reaction temperature was 20°C, the reaction time was 10 min, the hydrogen pressure was 1 bar, and the rest of the process was the same as in Example A1. After the reaction, the hydrogen pressure dropped to 0.8 bar, the hydrogen peroxide concentration was measured after the reaction, and the hydrogen peroxide conversion rate was calculated and listed in Table 6.

[0605] Comparative Example A1

[0606] This comparative example follows the method in Example A1, except that catalyst C1 is replaced with catalyst D1 prepared in Comparative Example A1, and the rest of the process is the same as in Example A1; the hydrogen pressure is increased to 2.6 bar after the reaction, the hydrogen peroxide concentration is measured after the reaction, and the hydrogen peroxide conversion rate is calculated and listed in Table 6.

[0607] Comparative Example A2

[0608] This comparative example follows the method in Example A1, except that catalyst C1 is replaced with catalyst D2 prepared in Comparative Example A2, and the rest of the process is the same as in Example A1; after the reaction, the hydrogen pressure increases to 2.7 bar, the hydrogen peroxide concentration is measured to be 57 ppm, and the hydrogen peroxide conversion rate is 98.86%.

[0609] The hydrogen peroxide concentration, conversion rate, and hydrogen consumption after the reaction of the above examples and comparative examples are listed in Table 6 below.

[0610] Table 6

[0611] In Comparative Example A1, catalyst D1 used Pt as the active metal component, while in Comparative Example A2, catalyst D2 used Ru as the active metal component. After changing the active center, although hydrogen peroxide could still be converted, the pressure increased after the reaction. This indicates that Pt and Ru are the active centers for hydrogen peroxide decomposition, generating oxygen and causing the pressure increase. However, when Pd is used as the hydrogenation center for hydrogen peroxide, the pressure decreases after the reaction due to hydrogen consumption. This demonstrates that changing the type of active metal component cannot achieve the hydrogenation of hydrogen peroxide to water. Only the hydrogenation catalyst provided by this invention (with Pd as the active metal component) can convert hydrogen peroxide in epichlorohydrin wastewater into water.

[0612] A comparison of the results from Examples A1-A4 shows that increasing the catalyst feed rate, reaction temperature, and catalyst active center loading can improve the reaction activity and shorten the time required to achieve the same hydrogen peroxide conversion rate under the same reaction conditions. This indicates that the preferred active metal loading, preferred catalyst feed rate, or preferred reaction conditions provided by this invention can achieve excellent catalytic hydrogenation effects.

[0613] Comparing the results of Examples A1 and A5-A6, it can be seen that when the catalyst particle size is greater than 80 mesh, further reducing the catalyst particle size has virtually no effect on the reaction activity; however, in Example A6, reducing the catalyst particle size reduced the reaction activity, requiring a further increase in the catalyst feed rate to achieve the same hydrogen peroxide conversion rate. Therefore, using the preferred catalyst mesh size (30-80 mesh) provided by this invention can achieve both suitable particle size and better catalytic activity.

[0614] Comparing the results of Examples A1 and A7, it can be seen that the reaction activity decreases after reducing the catalyst particle size. If the catalyst dosage is not changed, the hydrogen pressure needs to be increased in Example A7 to achieve the same hydrogen peroxide conversion rate. Therefore, the preferred catalyst mesh size (30-80 mesh) provided by the present invention can achieve better catalytic activity while having a suitable particle size.

[0615] Comparing the results of Example A1 and Example A8, it can be seen that in Example A8, after reducing the specific surface area of ​​the catalyst support, the hydrogenation activity of the catalyst decreased, the hydrogen consumption decreased, and the hydrogen peroxide conversion rate decreased. This indicates that the hydrogenation catalyst with a preferred specific surface area used in Example A1 can obtain better hydrogen peroxide hydrogenation catalytic activity.

[0616] Comparing the results of Examples A1 and A9, it can be seen that while keeping the specific surface area of ​​the catalyst support basically unchanged, reducing the proportion of microporous specific surface area leads to a decrease in the hydrogenation activity of the catalyst, a reduction in hydrogen consumption, and a decrease in the hydrogen peroxide conversion rate. This indicates that the hydrogenation catalyst with the preferred proportion of microporous specific surface area used in Example A1 has higher catalytic activity.

[0617] Comparing the results of Examples A1 and A10-A11, it can be seen that reducing the number of active sites on the catalyst decreases the catalyst activity (the active metal component loading of catalyst C7 is 0.1 wt%), and the hydrogen peroxide conversion rate decreases within the same time period. Conversely, increasing the number of active sites on the catalyst increases the catalyst activity (the active metal component loading of catalyst C8 is 2.0 wt%), and the time required to achieve the same hydrogen peroxide conversion rate is significantly shortened. However, further increasing the active site loading leads to increased catalyst cost. Therefore, when the active site component loading of the catalyst is within the preferred range provided by this invention, both catalyst activity and cost can be balanced.

[0618] Comparing the results of Examples A1 and A12, it can be seen that in Example A12, increasing the calcination and reduction temperature of catalyst C9 reduces its activity and the hydrogen peroxide conversion rate. When the catalyst preparation conditions are within the preferred range provided by this invention, the resulting catalyst exhibits superior catalytic activity.

[0619] Comparing the results of Example A1 and Example A13, it can be seen that under the condition of further increasing the amount of catalyst added, not only does the cost of using the catalyst increase, but the external diffusion mass transfer effect of the catalyst is also affected. Under the same conditions, the hydrogen peroxide conversion rate decreases, indicating that the preferred catalyst addition weight ratio provided by the present invention in Example A1 can have a better catalytic effect.

[0620] Comparing the results of Example A1 and Example A14, it can be seen that reducing the reaction temperature, reaction time, and reaction hydrogen pressure leads to a decrease in reaction activity and a significant decrease in hydrogen peroxide conversion rate. This indicates that the hydrogen peroxide catalytic hydrogenation reaction carried out in Example A1 according to the process conditions provided by the present invention can achieve better catalytic effect.

[0621] (V) Separation of epichlorohydrin synthesis products

[0622] Example 1

[0623] (1) Take 65.25g of epichlorohydrin, 6.89g of 3-chloropropene, and 0.36g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 90%, the mass fraction of 3-chloropropene is 9.5% and the mass fraction of 1-chloropropane is 0.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0624] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 35, and the reflux ratio was 10. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% other components; the bottom product contained 99.9% epichlorohydrin and 0.1% other components.

[0625] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 6.19 g of 50 wt% hydrogen peroxide aqueous solution (molar ratio of 3-chloropropene to hydrogen peroxide is 0.99:1), and 20.46 g of methanol (molar ratio of methanol to 3-chloropropene is 7:1) were added to prepare the titanium-silicon molecular sieve catalyst (5 wt% of the total liquid mass) prepared in Example 1. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 40 °C, and the reaction time was 75 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The supernatant was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0626] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0627] Example 2

[0628] (1) Take 65.25g of epichlorohydrin, 26.57g of 3-chloropropene, and 1.40g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 70%, the mass fraction of 3-chloropropene is 28.5%, and the mass fraction of 1-chloropropane is 1.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0629] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 30, and the reflux ratio was 15. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% of other components by mass; the bottom product contained 99.9% epichlorohydrin and 0.1% of other components by mass.

[0630] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 6.19 g of 50 wt% hydrogen peroxide aqueous solution, and 20.46 g of methanol were added to prepare the titanium-silicon molecular sieve catalyst (7 wt% of the total liquid mass) prepared in Example 2. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 40 °C, and the reaction time was 60 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The clear liquid was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0631] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0632] Example 3

[0633] (1) Take 65.25g of epichlorohydrin, 61.99g of 3-chloropropene, and 3.26g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 50%, the mass fraction of 3-chloropropene is 47.5% and the mass fraction of 1-chloropropane is 2.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0634] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 40, and the reflux ratio was 20. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% of other components by mass; the bottom product contained 99.9% epichlorohydrin and 0.1% of other components by mass.

[0635] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 6.19 g of 50 wt% hydrogen peroxide aqueous solution, and 20.46 g of methanol were added to prepare the titanium-silicon molecular sieve catalyst (9 wt% of the total liquid mass) prepared in Example 3. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 40 °C, and the reaction time was 30 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The supernatant was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0636] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0637] Example 4

[0638] (1) Take 65.25g of epichlorohydrin, 144.64g of 3-chloropropene, and 7.61g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 30%, the mass fraction of 3-chloropropene is 66.5% and the mass fraction of 1-chloropropane is 3.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0639] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 25, and the reflux ratio was 30. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% of other components by mass; the bottom product contained 99.9% epichlorohydrin and 0.1% of other components by mass.

[0640] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 6.19 g of 50 wt% hydrogen peroxide aqueous solution, and 20.46 g of methanol were added to prepare the titanium-silicon molecular sieve catalyst (9 wt% of the total liquid mass) prepared in Example 4. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 50 °C, and the reaction time was 60 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The clear liquid was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0641] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0642] Example 5

[0643] (1) Take 65.25g of epichlorohydrin, 557.89g of 3-chloropropene, and 29.36g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 10%, the mass fraction of 3-chloropropene is 85.5% and the mass fraction of 1-chloropropane is 4.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0644] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 45, and the reflux ratio was 30. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% of other components by mass; the bottom product contained 99.9% epichlorohydrin and 0.1% of other components by mass.

[0645] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 6.51 g of 50 wt% hydrogen peroxide aqueous solution, and 20.46 g of methanol were added to prepare the titanium-silicon molecular sieve catalyst (9 wt% of the total liquid mass) prepared in Example 1. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 40 °C, and the reaction time was 30 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The clear liquid was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0646] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0647] Example 6

[0648] (1) Take 65.25g of epichlorohydrin, 6.89g of 3-chloropropene, and 0.36g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 90%, the mass fraction of 3-chloropropene is 9.5% and the mass fraction of 1-chloropropane is 0.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0649] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 35, and the reflux ratio was 10. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% of other components by mass; the bottom product contained 99.9% epichlorohydrin and 0.1% of other components by mass.

[0650] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 6.80 g of 50 wt% hydrogen peroxide aqueous solution, and 20.46 g of methanol were added to prepare the titanium-silicon molecular sieve catalyst (9 wt% of the total liquid mass) prepared in Example 1. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 40 °C, and the reaction time was 30 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The clear liquid was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0651] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0652] Example 7

[0653] (1) Take 65.25g of epichlorohydrin, 6.89g of 3-chloropropene, and 0.36g of 1-chloropropane and mix them to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, wherein the mass fraction of epichlorohydrin is 90%, the mass fraction of 3-chloropropene is 9.5% and the mass fraction of 1-chloropropane is 0.5%, that is, the mass ratio of 3-chloropropene to 1-chloropropane is 95:5.

[0654] The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin was subjected to distillation. The reboiler temperature was 110°C, the top pressure was 80 kPa (absolute), the top temperature was 35°C, the theoretical plate number was 35, and the reflux ratio was 10. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the top product contained 94.9% 3-chloropropene, 5% 1-chloropropane, and 0.1% of other components by mass; the bottom product contained 99.9% epichlorohydrin and 0.1% of other components by mass.

[0655] (2) In a three-necked flask equipped with a thermometer and a reflux condenser, 7.25 g of the top product containing 3-chloropropene and 1-chloropropane obtained in step (1) (mass ratio of 3-chloropropene to 1-chloropropane is 95:5), 7.47 g of 50 wt% hydrogen peroxide aqueous solution, 20.46 g of methanol, and 0.25% ammonia water (molar ratio of ammonia water to hydrogen peroxide is 0.002:1) were added to prepare the titanium-silicon molecular sieve catalyst (5 wt% of the total liquid mass) prepared in Example 1. The three-necked flask was placed in a water bath with electromagnetic stirring, and a stir bar was added to the solution. The stirring speed was 300 rpm. The water bath was heated to the reaction temperature of 40 °C, and the reaction time was 75 min. After the reaction was stopped, the three-necked flask was transferred to an ice-water bath for uniform cooling. The supernatant was separated by centrifugation and subjected to titration analysis and gas chromatography analysis. The conversion rate of 3-chloropropene and the selectivity of epichlorohydrin were calculated and are shown in Table 7.

[0656] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 7.

[0657] Example 8

[0658] The procedure was carried out according to Example 1, except that 10.32 g of 30 wt% hydrogen peroxide aqueous solution was added in step (2). The relevant results are shown in Table 7.

[0659] Example 9

[0660] The procedure was carried out according to Example 1, except that the catalyst used in step (2) was the titanium-silicon molecular sieve catalyst prepared in Comparative Example 1. The relevant results are shown in Table 7.

[0661] Example 10

[0662] The procedure was carried out according to Example 1, except that the catalyst used in step (2) was the titanium-silicon molecular sieve catalyst prepared in Comparative Example 2. The relevant results are shown in Table 7.

[0663] Table 7

[0664] As shown in Table 7, the method of this invention can first separate a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, simultaneously obtaining high-purity epichlorohydrin and a light component of 3-chloropropene containing 1-chloropropane. Subsequently, under conditions of excess hydrogen peroxide, most or all of the 3-chloropropene in the 1-chloropropane-containing 3-chloropropene is converted to epichlorohydrin, yielding an epoxidation reaction product containing 1-chloropropane. Finally, after distillation separation, the mass fraction of 1-chloropropane in the top product increases to over 60%, the mass fraction of 3-chloropropene decreases to below 35%, while the mass fraction of 1-chloropropane in the bottom product is close to 0, and the mass fraction of epichlorohydrin is above 20%.

[0665] (vi) Examples of epichlorohydrin production

[0666] The following examples illustrate improvements to the existing production process for synthesizing epichlorohydrin from 3-chloropropene, wherein existing titanium-silicon molecular sieve catalysts are used in the synthesis step of synthesizing epichlorohydrin from 3-chloropropene, and the technical solutions of the present invention are adopted in product separation and wastewater treatment.

[0667] S1. In a water bath reactor, add 3-chloropropene containing 1-chloropropane (mass ratio of 3-chloropropene to 1-chloropropane is 97:3), 30wt% hydrogen peroxide aqueous solution (molar ratio of 3-chloropropene to hydrogen peroxide is 2.5:1), methanol (molar ratio of methanol to hydrogen peroxide is 5:1), and titanium silicate molecular sieve catalyst (3wt% of the total mass of the above reaction solution, produced by Hunan Jianchang Petrochemical Co., Ltd., brand name HTS). After sealing the reactor, purge with nitrogen until the pressure reaches 0.4MPa, and stir at 300rpm. The water bath temperature was set to 50℃, and the reaction time was 30 min. After the reaction was stopped, a 15℃ circulating cold water bath was introduced to cool the reactor uniformly. After separating the catalyst, a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water, and hydrogen peroxide was obtained. Chromatographic analysis showed that the epichlorohydrin content was 13%, the 3-chloropropene content was 15%, the 1-chloropropane content was 1%, the methanol content was 56%, the water content was 14.9%, and the hydrogen peroxide content was 0.1%.

[0668] S2. The solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water, and hydrogen peroxide obtained in S1 is mixed with allyl chloride and water and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, as well as a solution containing methanol, water, and hydrogen peroxide. Chromatographic analysis shows that in the solution containing the mixture of 3-chloropropene, 1-chloropropane, and epichlorohydrin, the content of 3-chloropropene is 85.5%, the content of 1-chloropropane is 4.5%, and the content of epichlorohydrin is 10%. In the solution containing methanol, water, and hydrogen peroxide, the content of methanol is 50%, the content of water is 49.9%, and the content of hydrogen peroxide is 0.1%.

[0669] S3. The mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin obtained in S2 is subjected to separation of 3-chloropropene and 1-chloropropane, as follows:

[0670] (1) The mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin obtained from S2 was subjected to distillation. The bottom temperature was 110℃, the top pressure was 80 kPa (absolute pressure), the top temperature was 35℃, the theoretical plate number was 45, and the top reflux ratio was 30. Gas chromatography was used to analyze the top and bottom products. Calculations showed that the mass fraction of 3-chloropropene in the top product was 94.9%, the mass fraction of 1-chloropropane was 5%, and the mass fraction of other components was 0.1%; the mass fraction of epichlorohydrin in the bottom product was 99.9%, and the mass fraction of other components was 0.1%.

[0671] (2) 50g of the catalyst prepared in Example 1 was loaded into a tubular fixed-bed reactor. The reaction tubing jacket oil bath temperature was 50℃, the reaction pressure was 0.4MPa, the feed mass ratio of 3-chloropropene to 1-chloropropane was 95:5, the feed molar ratio of 3-chloropropene to hydrogen peroxide was 0.99:1, the feed molar ratio of methanol to 3-chloropropene was 8:1, the feed molar ratio of ammonia to hydrogen peroxide was 0.002:1, and the feed mass hourly space velocity of the hydrogen peroxide aqueous solution (50wt%) was 0.11h. -1 The reaction was carried out under the specified conditions. Samples of the reactor outlet reaction solution were taken over a certain period of time for titration and gas chromatography analysis. The calculated conversion rate of 3-chloropropene and the selectivity of epichlorohydrin are shown in Table 8.

[0672] (3) The reaction solution was subjected to atmospheric distillation at a constant pressure. The bottom temperature of the column was 90℃, the top temperature was 45℃, the theoretical plate number was 10, and the top reflux ratio was 1. Gas chromatography was used to analyze the top and bottom products. The calculated mass fractions of 1-chloropropane and 3-chloropropene in the top product, and the mass fractions of 1-chloropropane and epichlorohydrin in the bottom product are shown in Table 8.

[0673] S4. In a hydrogen atmosphere, the solution containing methanol, water, and hydrogen peroxide obtained in S2 is subjected to a catalytic hydrogenation reaction with a palladium-on-carbon catalyst (catalyst C1 obtained in preparation example A1) to obtain a methanol-water solution. Chromatographic analysis shows that the methanol content is 50%, the water content is 50%, and the hydrogen peroxide content is <100 ppm. The methanol-water solution is then subjected to distillation. The distillation column operating conditions are: atmospheric pressure, bottom temperature 80°C, top temperature 65°C, theoretical plate number 50, and top reflux ratio 10. Chromatographic analysis of the top sample shows that the methanol content is 99%, with the remainder being water. The methanol is recycled.

[0674] Table 8

[0675] As shown in Table 8, the method of this invention, in a fixed-bed reactor, can convert most of the 3-chloropropene in 3-chloropropene containing 1-chloropropane into epichlorohydrin. This example also illustrates that this invention can provide a highly efficient method for producing epichlorohydrin. The above results demonstrate that this method has good prospects for industrial application.

[0676] The method provided by this invention has the potential to reuse the portion of 3-chloropropene containing a high concentration of 1-chloropropane that is periodically discharged during the epichlorohydrin production process, avoiding resource waste and reducing production costs and environmental burden. This process effectively separates 1-chloropropane from 3-chloropropene, converting 3-chloropropene into epichlorohydrin, which has higher economic value; it has significant practical implications for reducing material and energy consumption in the hydrogen peroxide-based epichlorohydrin production process.

[0677] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0678] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0679] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for producing epichlorohydrin, the method comprising the following steps: A1. In the presence of a catalyst and solvent, 3-chloropropene and hydrogen peroxide are reacted to produce a mixture containing epichlorohydrin and a waste liquid containing hydrogen peroxide; and A2. In a hydrogen atmosphere, waste liquid containing hydrogen peroxide is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst. The method may also optionally include the following steps: A3. Separate the mixture containing epichlorohydrin; Its features are, The catalyst used in step A1 is a titanium-silicon molecular sieve catalyst, which comprises titanium-silicon molecular sieve and inorganic oxides. Based on the total mass of the catalyst, the content of titanium-silicon molecular sieve is 70-95 wt%, and the content of inorganic oxides is 5-30 wt%; wherein, the lateral crushing strength of the catalyst is 60-150 N / cm; and / or The hydrogenation catalyst used in step A2 includes an activated carbon support and an active metal component; the active metal component includes Pd; and / or The catalyst used in step A1 is prepared by a process including the following steps: mixing and molding a titanium-silicon molecular sieve precursor containing a template agent, an inorganic oxide precursor (such as an alumina precursor), and an extrusion aid, followed by drying and calcination; and / or The hydrogenation catalyst used in step A2 is prepared by a process including the following steps: (1) impregnating and drying an activated carbon support with an active metal precursor solution to obtain a catalyst precursor, wherein the active metal component includes Pd; and (2) calcining and reducing the catalyst precursor under hydrogen conditions.

2. The method for producing epichlorohydrin according to claim 1, characterized in that... The catalyst used in step A1 has the following properties: The inorganic oxide is selected from alumina, silicon oxide, and boron oxide, and alumina accounts for 80 wt% or more of the inorganic oxide; and / or The total content of titanium silicate molecular sieves and inorganic oxides is ≥98 wt%; and / or The content of titanium silicate molecular sieve and inorganic oxide is 70-90 wt% and 10-30 wt%, respectively; and / or The catalyst has a lateral crushing strength of 60-150 N / cm; and / or In the titanium-silicon molecular sieve, the mass fraction of titanium, calculated as TiO2, is 1-10%; and / or The titanium-silicon molecular sieve is selected from at least one of the titanium-silicon molecular sieves having MFI structure, MEL structure, BEA structure, MSE structure and MWW structure; and / or The catalyst used in step A2 has the following properties: Based on the total weight of the hydrogenation catalyst, the content of the active metal component is 0.1-13% by weight, preferably 0.5-1% by weight; and / or The total specific surface area of ​​the hydrogenation catalyst is 1100-2000 m². 2 / g, preferably 1500-2000m 2 / g; particle size is 10-180 mesh, preferably 20-110 mesh; and / or The microporous specific surface area of ​​the hydrogenation catalyst accounts for 90-100% of the total specific surface area.

3. The method for producing epichlorohydrin according to claim 1, characterized in that... The catalyst used in step A1 is prepared by a process including the following steps: A titanium-silicon molecular sieve precursor containing a template agent, an inorganic oxide precursor, and an extrusion aid are mixed and molded, then dried and calcined. The mass of the extrusion aid is 5-25% of the dry basis mass of the titanium-silicon molecular sieve precursor; and / or The extrusion aid is selected from guar gum powder, methylcellulose, soluble starch, and citric acid; and / or The template agent content in the titanium-silicon molecular sieve precursor is 1-20 wt%; and / or In the titanium-silicon molecular sieve precursor, the mass fraction of titanium, calculated as TiO2, is 1-10% based on the dry basis mass of the titanium-silicon molecular sieve precursor. and / or The template agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; and / or The preparation method of the titanium-silicon molecular sieve precursor containing the template agent includes: mixing a titanium source, a silicon source, a template agent, and water; performing hydrothermal crystallization; and then drying; and / or The method for preparing the titanium-silicon molecular sieve precursor containing the template agent does not include calcining the dried material; and / or The amount of the titanium-silicon molecular sieve precursor containing the template agent and the inorganic oxide precursor is such that, based on the total mass of the catalyst, the content of the titanium-silicon molecular sieve is 70-95 wt%; the content of the inorganic oxide is 5-30 wt%; and / or The alumina precursor includes alumina sol and optionally aluminum hydroxide powder or hydrated alumina powder. For example, the mass ratio of aluminum hydroxide powder or hydrated alumina powder to aluminum sol is 0-50:50-100, wherein the aluminum sol and the water and alumina powder are calculated as alumina; and / or the aluminum sol is an acidic aluminum sol with a pH value of 2-4; and / or the solid content of the aluminum sol is 20-30 wt%; and / or the specific surface area of ​​the aluminum hydroxide powder or hydrated alumina powder is 270-500 m². 2 / g, pore volume of 0.5-1.2 mL / g; and / or The calcination conditions include: a temperature of 400-800℃; a time of 2-20 hours; and / or The method for preparing the catalyst includes not adding a pore-forming agent; and / or The hydrogenation catalyst used in step A2 is prepared by a process including the following steps: (1) An activated carbon support is impregnated with an active metal precursor solution and then dried to obtain a catalyst precursor; wherein The active metal precursor is selected from one or more of palladium acetate, palladium nitrate, palladium chloride, and palladium oxalate; and / or The concentration of palladium ions in the active metal precursor solution is 0.05-7% by weight, for example, 0.05-5.5% by weight, or 0.25-0.50% by weight; and / or The impregnation treatment is an equal volume impregnation; and / or The conditions for the impregnation treatment include: an impregnation temperature of 20-30℃ and an impregnation time of 10-15 hours; and / or The drying conditions include: a drying temperature of 100-120℃ and a drying time of 6-10 hours; (2) The catalyst precursor is subjected to calcination and reduction treatment under hydrogen conditions; wherein the conditions for calcination and reduction treatment include: The reduction temperature is 300-750℃, preferably 300-620℃; The restoration time is 2-8 hours; The hydrogen flow rate is 5-100 mL / min.

4. The method for producing epichlorohydrin according to claim 1, characterized in that... The conditions for the epoxidation reaction described in step A1 include: The molar ratio of 3-chloropropene to hydrogen peroxide is 0.8-3:1; and / or The hydrogen peroxide is provided in the form of an aqueous solution of hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the aqueous solution is 10-90%, for example 20-70%, such as 20%, 30%, 40%, 50%, 60%, or 70%; and / or The solvent is selected from at least one of alcohols having 1-6 carbon atoms, ketones having 3-4 carbon atoms, ethers having 2-10 carbon atoms, nitriles having 2-4 carbon atoms, and carboxylic acid esters having 2-6 carbon atoms; preferably, the solvent is methanol; and / or The molar ratio of solvent to hydrogen peroxide is 4-20:1; and / or The amount of catalyst used is 0.5-10 wt% of the total mass of the reaction solution, for example, 2-5 wt%.

5. The method for producing epichlorohydrin according to claim 1, characterized in that... The conditions for the catalytic hydrogenation reaction described in step A2 include: The reaction temperature is 20-50℃, the reaction time is 10-60 min, and the hydrogen pressure is 1-10 bar; and / or Based on the total weight of the waste liquid containing hydrogen peroxide, the hydrogen peroxide content is 0.05-3% by weight; and / or The weight ratio of the waste liquid containing hydrogen peroxide to the hydrogenation catalyst is 100:0.1-7.

6. The method for producing epichlorohydrin according to claim 1, characterized in that... The method includes the following steps: A1. In the presence of a catalyst, 3-chloropropene containing 1-chloropropane and hydrogen peroxide are subjected to an epoxidation reaction in methanol solvent to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, methanol, water and hydrogen peroxide. The solution containing epichlorohydrin, 3-chloropropene, 1-chloropropene, methanol, water and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropene and epichlorohydrin and a solution containing methanol, water and hydrogen peroxide. A2. In a hydrogen atmosphere, the solution containing methanol, water and hydrogen peroxide obtained in A1 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing methanol and water; then, optionally, the solution containing methanol and water is subjected to distillation to obtain methanol for recycling. A3. Separate 3-chloropropene and 1-chloropropane from the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin obtained in A1.

7. The method for producing epichlorohydrin according to claim 6, characterized in that... In the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin obtained in step A1, the mass fraction of epichlorohydrin is 10-90%, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1, for example 90:10-97:3; In the solution containing methanol, water, and hydrogen peroxide obtained in step A1, the content of hydrogen peroxide is 0.05-3% by weight; the content of methanol is 20-80% by weight; and / or In the catalytic hydrogenation reaction of step A2, the weight ratio of the solution containing methanol, water and hydrogen peroxide to the hydrogenation catalyst is 100:0.1-7.

8. The method for producing epichlorohydrin according to claim 1, characterized in that... The method includes the following steps: A1. In the presence of a catalyst and a solvent, an aqueous solution of 3-chloropropene containing 1-chloropropane and hydrogen peroxide is subjected to an epoxidation reaction to obtain a solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, solvent, water and hydrogen peroxide; the solution containing epichlorohydrin, 3-chloropropene, 1-chloropropane, solvent, water and hydrogen peroxide is mixed with an extractant and then separated to obtain a mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, and a waste liquid containing solvent, water and hydrogen peroxide; In the mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin, the mass fraction of epichlorohydrin is 10-90%, the total mass fraction of 3-chloropropene and 1-chloropropane is 10-90%, and the mass ratio of 3-chloropropene to 1-chloropropane is 80:20-99:1, for example 90:10-97:3; A2. In a hydrogen atmosphere, the waste liquid containing solvent, water, and hydrogen peroxide obtained in step A1 is subjected to a catalytic hydrogenation reaction with a hydrogenation catalyst to obtain a solution containing solvent and water; then, optionally, the solution containing solvent and water is subjected to distillation to obtain the solvent; and A3. Separating a mixture containing 3-chloropropene, 1-chloropropane, and epichlorohydrin, the separation methods include: (1) The mixture containing 3-chloropropene, 1-chloropropane and epichlorohydrin is subjected to a first distillation separation in a first distillation column to obtain a top product containing 3-chloropropene and 1-chloropropane and a bottom product containing epichlorohydrin. (2) Under the action of a catalyst, the top product obtained in step (1) is reacted with hydrogen peroxide; wherein, the molar ratio of 3-chloropropene to hydrogen peroxide in the top product is 0.7-0.99:1, for example 0.8-0.99:1; preferably, the catalyst in step (2) is selected from the titanium-silicon molecular sieve catalyst of claim 1. (3) The reaction product obtained in step (2) is subjected to a second distillation in a second distillation column to obtain a top product rich in 1-chloropropane and a bottom product rich in epichlorohydrin; wherein the mass fraction of 1-chloropropane in the top product is not less than 10% and the mass fraction of 1-chloropropane in the bottom product is not more than 0.1%.

9. The method for producing epichlorohydrin according to claim 8, characterized in that... In the top product obtained in step A3(1), the total mass fraction of 3-chloropropene and 1-chloropropane is not less than 99%; and / or The mass content of 3-chloropropene in the top product obtained in step A3 (1) is 80-98%. The mass content of 1-chloropropane is 2-20%; and / or The distillation separation conditions described in step A3(1) include: bottom temperature of 81-129℃, top temperature of 30-60℃, top pressure of 60-101kPaA, theoretical plate number of 10-50, and top reflux ratio of 1-50.

10. The method for producing epichlorohydrin according to claim 8, characterized in that... In the reaction described in step A3(2), The conversion rate of 3-chloropropene is not less than 95%; the conversion rate of 1-chloropropane is not more than 5%; and / or The reaction temperature is 10-90℃; and / or The hydrogen peroxide is provided in the form of an aqueous solution of hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the aqueous solution is not less than 50%; and / or The catalyst is used at a mass percentage of 0.1-40% of the total mass of the liquid-phase feed; and / or The reaction is carried out in a fixed-bed reactor.

11. The method for producing epichlorohydrin according to claim 8, characterized in that... In step A3(2), a solvent is also added to the reaction, wherein The solvent is selected from at least one of alcohols having 1-6 carbon atoms, ketones having 3-4 carbon atoms, ethers having 2-10 carbon atoms, nitriles having 2-4 carbon atoms, and carboxylic acid esters having 2-6 carbon atoms; preferably, the solvent is methanol; and / or The molar ratio of solvent to 3-chloropropene is 4-20:1; and / or The molar ratio of solvent to hydrogen peroxide is 4-20:1; and / or In step (2), an alkaline additive is also added to the reaction, wherein... The alkaline additive is selected from at least one of ammonia, alkaline ammonium salts, organic amines, and quaternary ammonium bases; and / or The molar ratio of alkaline additive to hydrogen peroxide is 0.001-0.05:

1.

12. The method for producing epichlorohydrin according to claim 8, characterized in that... The distillation separation conditions described in step (3) include: bottom temperature of 81-119℃, top temperature of 40-50℃, top pressure of 60-101kPaA, theoretical plate number of 10-50, and top reflux ratio of 0.5-5.

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