A method for the synthesis of epichlorohydrin

Abstract

The application discloses a synthesis method of epichlorohydrin, at least comprising the following steps: passing a homogeneous mixture containing chloropropene, hydrogen peroxide, polyhydric alcohol and ionic surfactant into a continuous reactor to react, and obtaining a product containing epichlorohydrin. Compared with a traditional method, the application has less by-products, the product after hydrogen peroxide reaction is water, the ionic surfactant and the polyhydric alcohol are added to promote the mixing of an organic phase and an aqueous phase into a homogeneous phase, improve selectivity, a large amount of solvent does not need to be added, solvent evaporation recovery and other processes are avoided, the process is energy-saving and environment-friendly, equipment and process are simple, yield and selectivity are high, the method is suitable for large-scale production in industry, has great economic benefits, solvent evaporation and recovery are not needed, is beneficial to production amplification in industry, equipment maintenance cost is low, system cost is relatively low, environmental pollution is small, operation is simple, is easy to repeat, and epichlorohydrin can be efficiently produced.

Description

Technical Field

[0001] This application relates to a method for synthesizing epichlorohydrin, which uses hydrogen peroxide as an oxygen source and titanium silicate molecular sieve TS-1 as a catalyst to catalyze the direct oxidation of allyl chloride to prepare epichlorohydrin, belonging to the field of epichlorohydrin preparation and synthesis. Background Technology

[0002] Epichlorohydrin is an important organic chemical raw material and fine chemical product with a wide range of applications. Epoxy resins made from it possess strong adhesion, resistance to chemical corrosion, low shrinkage, good chemical stability, high impact strength, and excellent dielectric properties, making them widely used in coatings, adhesives, reinforcing materials, casting materials, and electronic laminates. Since the beginning of the 21st century, the application areas of epoxy resins have continued to expand, and production has increased rapidly. my country is currently the world's largest epoxy resin production base, and the demand for epichlorohydrin is expected to continue to grow.

[0003] Currently, there are three main industrial production methods for ECH (Enriched Chlorinated Hydrocarbons) worldwide: the propylene high-temperature chlorination process, the propylene acetate process, and the glycerol process. Among these, the propylene high-temperature chlorination process is the most prevalent method both domestically and internationally, while the glycerol process, due to its economic and environmental advantages, is expected to become the future direction of ECH technology. However, this method is significantly affected by the price of glycerol, resulting in substantial market price fluctuations.

[0004] The hydrogen peroxide direct oxidation process for epichlorohydrin (ECH) is a novel and environmentally friendly production process to date, and it is poised to lead the future development of epichlorohydrin. This method originated in the 1980s when Interox Chemicals in the UK successfully synthesized epichlorohydrin at 100-110℃ using peroxyacid and allyl chloride in an epoxidation reaction. Currently, the direct epoxidation of allyl chloride to ECH generally uses hydrogen peroxide, peroxyacid, alkoxy hydrogen peroxide, or molecular oxygen as oxygen sources. Significant breakthroughs have been achieved using hydrogen peroxide as the oxidant, with several units expected to be built in the coming years. However, current processes typically use a large amount of solvent to dissolve the reactants allyl chloride and hydrogen peroxide to form a homogeneous phase. Insufficient solvent can lead to incomplete dissolution of the two phases, hindering mass and heat transfer, increasing side reactions, and reducing the yield and selectivity of epichlorohydrin. However, the use of solvents increases production costs on the one hand, and requires a lot of energy to evaporate and recycle the solvents on the other hand, which restricts the industrialization of this process in many ways. Summary of the Invention

[0005] According to one aspect of this application, a method for preparing epichlorohydrin is provided. This method involves introducing an ionic surfactant and a polyol into a reaction system to form a homogeneous mixture of allyl chloride and hydrogen peroxide. The mixture is then pumped into a continuous reactor containing titanium silicate molecular sieve TS-1 via multiple metering pumps at a specific molar ratio, achieving continuous operation and directly epoxidizing allyl chloride to prepare epichlorohydrin. This method, by adding an ionic surfactant, promotes the mixing of the organic and aqueous phases, eliminating the need for large amounts of solvent added in traditional processes and avoiding energy-intensive processes such as solvent evaporation and recovery. The process is energy-efficient and environmentally friendly, with simple equipment and high epichlorohydrin yield and selectivity, making it suitable for large-scale industrial production of epichlorohydrin. Furthermore, the use of multiple metering pumps enables continuous production and simplifies operation. The solvent-free synthesis system used in this method offers significant economic benefits, with low system cost, minimal environmental pollution, simple operation, easy reproducibility, low equipment maintenance costs, and efficient production of epichlorohydrin.

[0006] At least the following steps are included:

[0007] A homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol, and ionic surfactant is passed into a continuous reactor for reaction to obtain a product containing epichlorohydrin.

[0008] The continuous reactor is filled with a catalyst containing titanium-silicon molecular sieve TS-1;

[0009] By introducing ionic surfactants and polyols into the reaction system, allyl chloride and hydrogen peroxide are made into a homogeneous oil-water mixture. The mixture is then pumped into a continuous reactor containing titanium-silicon molecular sieve TS-1 by multiple metering pumps according to a certain molar ratio, thus achieving continuous operation.

[0010] The polyol is selected from at least one of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, 1,4-cyclohexanediol, 1,4-cyclohexanediol, terephthalic acid, glycerol, trimethylolpropane, pentaerythritol, xylitol, or sorbitol.

[0011] The ionic surfactant is selected from at least one of anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0012] The molar ratio of allyl chloride to polyol is 5 to 10:1.

[0013] Optionally, the molar ratio of allyl chloride to polyol is independently selected from any value of 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1 or any value in between.

[0014] Optionally, the molar ratio of allyl chloride to polyol is 6 to 10:1;

[0015] Optionally, the molar ratio of the chloropropene to the polyol is 8 to 10:1.

[0016] The molar ratio of allyl chloride to hydrogen peroxide is 1 to 10:1.

[0017] Optionally, the molar ratio of allyl chloride and hydrogen peroxide is independently selected from any value of 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1 or any value between the two.

[0018] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 3 to 10:1;

[0019] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 5 to 10:1.

[0020] The molar ratio of hydrogen peroxide to ionic surfactant is 1 to 50:1.

[0021] Optionally, the molar ratio of hydrogen peroxide to the ionic surfactant is independently selected from any value of 1:1, 2:1, 3:1, 5:1, 10:1, 15:1, 20:1, 30:1, 40:1 or 50:1 or any value between the two.

[0022] Optionally, the molar ratio of hydrogen peroxide to ionic surfactant is 10 to 50:1;

[0023] Optionally, the molar ratio of hydrogen peroxide to ionic surfactant is 30-50:1.

[0024] The hydrogen peroxide has a mass concentration of 10-70%.

[0025] Optionally, the mass concentration of the hydrogen peroxide is independently selected from any value among 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, and 70%, or any value between both.

[0026] The reaction temperature is 20–90°C;

[0027] Optionally, the temperature of the reaction is independently selected from any value of 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, or any value between both.

[0028] The reaction time is 1 to 10 hours;

[0029] Optionally, the reaction time is independently selected from any value of 1 hour, 2 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours, or any value between any two.

[0030] The liquid flow rate of the reaction is 0.1–20 L / min.

[0031] Optionally, the liquid flow rate of the reaction is independently selected from any value of 0.1 L / min, 0.5 L / min, 1 L / min, 3 L / min, 5 L / min, 9 L / min, 12 L / min, 15 L / min or 20 L / min or any value between any two.

[0032] The anionic surfactant is selected from at least one of stearic acid and sodium dodecylbenzene sulfonate;

[0033] The cationic surfactant is selected from at least one of amine salt cationic surfactants and heterocyclic cationic surfactants;

[0034] The amine salt type cationic surfactant is selected from at least one of quaternary ammonium salt, primary amine salt, secondary amine salt and tertiary amine salt cationic surfactants;

[0035] The heterocyclic cationic surfactant is selected from at least one of nitrogen-containing morpholine ring, pyridine ring, imidazole ring, piperazine ring and quinoline ring heterocyclic cationic surfactants.

[0036] The zwitterionic surfactant is selected from at least one of lecithin-type, amino acid-type, and betaine-type zwitterionic surfactants.

[0037] The amine salt type cationic surfactant is selected from at least one of quaternary ammonium salt type cationic surfactants, primary amine salt type cationic surfactants, secondary amine salt type cationic surfactants, and tertiary amine salt type cationic surfactants;

[0038] The heterocyclic cationic surfactant is selected from at least one of nitrogen-containing morpholine cyclic cationic surfactants, pyridine cyclic cationic surfactants, imidazole cyclic cationic surfactants, piperazine cyclic cationic surfactants, and quinoline cyclic cationic surfactants.

[0039] The titanium-silicon molecular sieve TS-1 is a titanium-doped silicon-based zeolite molecular sieve.

[0040] The titanium-silicon molecular sieve TS-1 has an MFI-type topology.

[0041] The beneficial effects that this application can produce include:

[0042] (1) This application provides a method for preparing epichlorohydrin. Compared with traditional methods, the preparation process of this invention uses titanium silicon molecular sieve TS-1 as a catalyst and hydrogen peroxide as an oxygen source to directly oxidize chloropropylene to epichlorohydrin. There are fewer reaction byproducts, and the product after hydrogen peroxide reaction is water, which has less environmental pollution and is green and environmentally friendly.

[0043] (2) By adding ionic surfactants and polyols, the organic phase and aqueous phase are mixed into a homogeneous phase, which improves the selectivity of the reaction. There is no need to add a large amount of solvent in the traditional process. The reaction solution after the reaction is clear and transparent, avoiding a large amount of energy-consuming processes such as solvent evaporation and recovery.

[0044] (3) The process is energy-saving and environmentally friendly, the equipment and process are simple, the epichlorohydrin yield and selectivity are high, and it is suitable for large-scale industrial production of epichlorohydrin. The solvent-free synthesis system used in this method has great economic benefits.

[0045] (4) It does not require the traditional energy-intensive solvent evaporation and recovery process, which is conducive to industrial production scale-up. The equipment maintenance cost is low, the system cost is low, the environmental pollution is small, the operation is simple and easy to repeat, and it can produce epichlorohydrin efficiently. Detailed Implementation

[0046] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0047] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0048] The analysis method in the embodiments of this application is as follows:

[0049] The selectivity of epichlorohydrin and the utilization rate of hydrogen peroxide during the reaction were detected using a gas chromatograph (model 7890A) manufactured by Agilent Technologies.

[0050] The selectivity of epichlorohydrin and the utilization rate of hydrogen peroxide were determined by gas chromatography.

[0051] The hydrogen peroxide conversion rate was detected by cerium sulfate titration, using ferrous 1,1-diphenoxyacetic acid as an indicator. The titration endpoint was when the light red solution turned into a transparent light blue solution.

[0052] Example 1

[0053] Multiple metering pumps were used to pump the solution into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride: 25% hydrogen peroxide: sodium dodecylbenzenesulfonate (an ionic surfactant): ethylene glycol of 50:5:2:2. The solution was passed through a heat exchanger at a flow rate of 10 L / min, heated to 45°C, and reacted continuously for 7 hours. After the reaction, a small amount of the reaction solution was taken for gas chromatography analysis and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 96.2%, the hydrogen peroxide utilization rate was 97%, and the selectivity for epichlorohydrin was 98.1%.

[0054] Example 2

[0055] Multiple metering pumps were used to pump the solution into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride: 50% hydrogen peroxide: sodium stearate (an ionic surfactant): pentaerythritol of 100:10:1:10. The solution was passed through a heat exchanger at a flow rate of 12 L / min, heated to 50 °C, and reacted continuously for 8 hours. After the reaction, a small amount of the reaction solution was taken for gas chromatography analysis and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 97.1%, the hydrogen peroxide utilization rate was 97%, and the selectivity for epichlorohydrin was 96.3%.

[0056] Examples 3-11

[0057] The specific ingredients, materials used, and reaction conditions are shown in Table 1 below. Other operations during the synthesis process are the same as in Example 1.

[0058] Table 1. Raw material composition, ratio, reaction conditions, and reaction results of Examples 3-11

[0059]

[0060] The test results for epichlorohydrin in other embodiments are similar to those described above, and epichlorohydrin was obtained through this invention.

[0061] Example 12

[0062] Multiple metering pumps were used to pump the solution into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride: 35% hydrogen peroxide: sodium dodecylbenzenesulfonate (an ionic surfactant): sorbitol of 50:5:1:5. The solution was passed through a heat exchanger at a flow rate of 10 L / min, heated to 50°C, and reacted continuously for 6 hours. After the reaction, a small amount of the reaction solution was taken for gas chromatography analysis and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 97.2%, the hydrogen peroxide utilization rate was 97%, and the selectivity for epichlorohydrin was 96.8%.

[0063] Comparative Example 1

[0064] Using the same reaction conditions as in Example 12, but without the addition of surfactants and polyols, the specific operation was as follows: Multiple metering pumps were used to pump the solution into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride to 35% hydrogen peroxide of 50:5. The solution was passed through a heat exchanger at a flow rate of 10 L / min, and the temperature was raised to 50°C. The continuous reaction time was 6 hours. After the reaction, a small amount of the reaction solution was taken for gas chromatography analysis and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 73.5%, the hydrogen peroxide utilization rate was 75%, and the selectivity for epichlorohydrin was 91.2%.

[0065] Example 13

[0066] Multiple metering pumps were used to pump the solution into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride: 50% hydrogen peroxide: ionic surfactant cetyl sulfate: polyethylene glycol 200 (35:5:1:5). The solution was passed through a heat exchanger at a flow rate of 10 L / min, heated to 65°C, and reacted continuously for 5 hours. After the reaction, a small amount of the reaction solution was taken for gas chromatography analysis and cerium sulfate titration of hydrogen peroxide. The results showed that the hydrogen peroxide conversion rate was 94.7%, the hydrogen peroxide utilization rate was 97%, and the epichlorohydrin selectivity was 96.3%.

[0067] Comparative Example 2

[0068] Using the same reaction conditions as in Example 13, but without the addition of ionic surfactants and polyols, and with the addition of the organic phase methanol, the specific operation was as follows: Multiple metering pumps were used to pump the reaction solution into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride: 50% hydrogen peroxide: methanol of 35:5:500. The solution was passed through a heat exchanger at a flow rate of 10 L / min, and the temperature was raised to 65°C. The continuous reaction time was 5 hours. After the reaction, a small amount of the reaction solution was taken for gas chromatography analysis and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 83.9%, the hydrogen peroxide utilization rate was 89%, and the epichlorohydrin selectivity was 92.7%.

[0069] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for synthesizing epichlorohydrin, characterized in that, At least the following steps are included: A homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol, and ionic surfactant is passed into a continuous reactor for reaction to obtain a product containing epichlorohydrin. The continuous reactor is filled with a catalyst containing titanium-silicon molecular sieve TS-1. The polyol is selected from at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, glycerol, pentaerythritol, or sorbitol. The ionic surfactant is selected from anionic surfactants; The molar ratio of allyl chloride to polyol is 5~10:1; The molar ratio of allyl chloride to hydrogen peroxide is 1~10:1; The molar ratio of hydrogen peroxide to ionic surfactant is 1~50:

1.

2. The method according to claim 1, characterized in that, The molar ratio of allyl chloride to polyol is 6~10:1; The molar ratio of allyl chloride to hydrogen peroxide is 3~10:1; The molar ratio of hydrogen peroxide to ionic surfactant is 10~50:

1.

3. The method according to claim 1, characterized in that, The molar ratio of allyl chloride to polyol is 8~10:1; The molar ratio of allyl chloride to hydrogen peroxide is 5~10:1; The molar ratio of hydrogen peroxide to ionic surfactant is 30~50:

1.

4. The method according to claim 1, characterized in that, The hydrogen peroxide has a mass concentration of 10-70%.

5. The method according to claim 1, characterized in that, The reaction temperature is 20~90℃; The reaction time is 1 to 10 hours; The liquid flow rate of the reaction is 0.1 ~ 20 L / min.

6. The method according to claim 1, characterized in that, The anionic surfactant is selected from at least one of sodium stearate and sodium dodecylbenzene sulfonate.

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