A process for the preparation of epichlorohydrin

Abstract

The application discloses a method for preparing epichlorohydrin, which comprises the following steps: reacting a mixture containing chloropropene, hydrogen peroxide, polyhydric alcohol, a catalyst and an ionic surfactant in a batch kettle reactor to obtain a product containing epichlorohydrin. Compared with the traditional method, the reaction has less by-products, the product after the reaction of hydrogen peroxide is water, the addition of the ionic surfactant and the polyhydric alcohol promotes the mixing of the organic phase and the aqueous phase into a homogeneous phase, improves the selectivity, a large amount of solvent does not need to be added, solvent evaporation and recovery processes are avoided, the process is energy-saving and environment-friendly, the equipment process is simple, the yield and the 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 the production amplification in industry, the equipment maintenance cost is low, the system cost is relatively low, the environmental pollution is small, the operation is simple, the method is easy to repeat, and epichlorohydrin can be efficiently produced.

Description

Technical Field

[0001] This application relates to a method for preparing 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 chloropropene to prepare epichlorohydrin, belonging to the field of epichlorohydrin preparation and synthesis. Background Technology

[0002] Epichlorohydrin (ECH) is an important organic chemical raw material and a crucial intermediate in the petrochemical industry. It is primarily used in the production of epoxy resins, glycerol, chlorohydrin rubber, and other derivatives. It can also be used as a solvent, plasticizer, flame retardant, and surfactant. Currently, the main production processes for epichlorohydrin are the glycerol method, the propylene high-temperature chlorination method (referred to as the propylene method), and the newer hydrogen peroxide method. In terms of production capacity share, the glycerol method is the primary method, the propylene method is secondary, and the hydrogen peroxide method has the lowest overall share.

[0003] Although the high-temperature chlorination process for producing epichlorohydrin from propylene is a mature technology, it has drawbacks such as severe equipment corrosion, high energy consumption, high chlorine consumption, and low conversion rate. Under increasingly stringent environmental protection requirements, this method for producing epichlorohydrin has been included in the restricted category of the "Guidance Catalogue for Industrial Structure Adjustment".

[0004] The glycerol-based epichlorohydrin production process boasts advantages such as mild reaction conditions, high selectivity and yield, low pollution, and minimal consumption of the byproduct hydrogen chloride, aligning with current national industrial policies. However, with the continuous release of new domestic glycerol-based epichlorohydrin production capacity, the demand for glycerol continues to rise, supporting glycerol market trends. In 2021, the price of 99.5% glycerol reached a high of 14,000 yuan / ton, leading to a sharp increase in the cost of the glycerol-based process. This has resulted in a high-cost, low-profit situation for epichlorohydrin, even causing losses in some periods. Looking ahead, most of the projects under construction (or planned) will utilize the glycerol-based process, with demand continuing to grow. Glycerol prices are unlikely to return to the previous low levels of 3,000-4,000 yuan / ton, thus the profit margin for glycerol-based epichlorohydrin may remain relatively low.

[0005] The hydrogen peroxide process for producing epichlorohydrin is an emerging technology and the most environmentally friendly production process for epichlorohydrin to date, poised to lead its future development. However, current processes typically use a significant amount of solvent to dissolve the reactants allyl chloride and hydrogen peroxide, forming 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. Furthermore, the use of solvent increases production costs and requires substantial energy for solvent evaporation and recovery, thus hindering the industrialization of this process. Summary of the Invention

[0006] According to one aspect of this application, a method for preparing epichlorohydrin is provided. This method includes using a titanium silicate molecular sieve TS-1 as a catalyst, and in the presence of allyl chloride, hydrogen peroxide, a polyol, and an ionic surfactant, directly epoxidizing allyl chloride in a batch reactor to prepare epichlorohydrin. This method promotes the mixing of the organic and aqueous phases by adding an ionic surfactant, 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-saving and environmentally friendly, with simple equipment and high epichlorohydrin yield and selectivity, making it suitable for large-scale industrial production of epichlorohydrin. The polyol synthesis system used in this method has significant economic benefits, low system cost, minimal environmental pollution, simple operation, easy reproducibility, low equipment maintenance costs, and efficient production of epichlorohydrin.

[0007] At least the following steps are included:

[0008] A mixture containing allyl chloride, hydrogen peroxide, polyol, catalyst and ionic surfactant is reacted in a batch reactor to obtain a product containing epichlorohydrin.

[0009] The catalyst contains titanium-silicon molecular sieve TS-1;

[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, and sorbitol.

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

[0012] The anionic surfactant is selected from at least one of stearic acid and sodium dodecylbenzene sulfonate;

[0013] The cationic surfactant is selected from at least one of amine salt cationic surfactants and heterocyclic cationic surfactants;

[0014] 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;

[0015] 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.

[0016] 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;

[0017] 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.

[0018] The zwitterionic surfactant is selected from at least one of lecithin-type, amino acid-type, and betaine-type zwitterionic surfactants.

[0019] The molar ratio of hydrogen peroxide to ionic surfactant is 1 to 50:1.

[0020] 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.

[0021] Optionally, the molar ratio of hydrogen peroxide to ionic surfactant is 10 to 50:1;

[0022] Optionally, the molar ratio of hydrogen peroxide to ionic surfactant is 30-50:1.

[0023] The molar ratio of allyl chloride to polyol is 5 to 10:1.

[0024] 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.

[0025] Optionally, the molar ratio of allyl chloride to polyol is 6 to 10:1;

[0026] Optionally, the molar ratio of the chloropropene to the polyol is 8 to 10:1.

[0027] The molar ratio of allyl chloride to hydrogen peroxide is 1 to 10:1.

[0028] 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.

[0029] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 3 to 10:1;

[0030] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 5 to 10:1.

[0031] The hydrogen peroxide has a mass concentration of 10-70%.

[0032] 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.

[0033] The titanium-silicon molecular sieve TS-1 is a titanium-doped silicon-based zeolite molecular sieve.

[0034] The titanium-silicon molecular sieve TS-1 has an MFI-type topology.

[0035] The mass of the catalyst is 0.1 to 10 wt% of the mass of allyl chloride.

[0036] Optionally, the mass of the catalyst is any value among 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt% of the mass of allyl chloride, or any value between both.

[0037] Optionally, the mass of the catalyst is 1 to 10 wt% of the mass of allyl chloride;

[0038] Optionally, the mass of the catalyst is 5 to 10 wt% of the mass of propylene chloride.

[0039] The reaction temperature is 20–90°C;

[0040] 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.

[0041] The reaction time is 1 to 10 hours.

[0042] 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 in between.

[0043] After the reaction is complete, a certain amount of the reaction solution is taken for testing of epichlorohydrin selectivity and hydrogen peroxide conversion and utilization.

[0044] Alternatively, the detection methods used are gas chromatography and hydrogen peroxide liquid titration.

[0045] Optionally, the conversion rate of hydrogen peroxide during the reaction is greater than 95%.

[0046] Optionally, the utilization rate of hydrogen peroxide during the reaction is greater than 95%.

[0047] Optionally, the selectivity of epichlorohydrin during the reaction process is between 95% and 99%.

[0048] The beneficial effects that this application can produce include:

[0049] (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. In a batch reactor, chloropropylene is directly oxidized to epichlorohydrin. There are fewer reaction by-products. The product after hydrogen peroxide reaction is water, which has less environmental pollution and is green and environmentally friendly.

[0050] (2) The method for preparing epichlorohydrin provided in this application is energy-saving and environmentally friendly, with simple equipment and processes, and high yield and selectivity of epichlorohydrin, which is suitable for large-scale industrial production.

[0051] (3) The method for preparing epichlorohydrin provided in this application promotes the mixing of the organic phase and the aqueous phase into a homogeneous phase by adding ionic surfactants and polyols, thereby improving the selectivity of the reaction. It does not require the addition of a large amount of solvent in the traditional process, and the reaction solution after the reaction is clear and transparent, avoiding a large amount of energy-consuming processes such as solvent evaporation and recovery.

[0052] (4) The method for preparing epichlorohydrin provided in this application does not require the traditional energy-intensive solvent evaporation and recovery process, which is conducive to industrial production scale-up, with low equipment maintenance costs, low system costs, low environmental pollution, simple operation, easy reproducibility, and efficient production of epichlorohydrin. Detailed Implementation

[0053] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0054] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0055] The analysis method in the embodiments of this application is as follows:

[0056] 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.

[0057] The selectivity of epichlorohydrin and the utilization rate of hydrogen peroxide were determined by gas chromatography.

[0058] 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.

[0059] Example 1

[0060] 5g of allyl chloride, 3g of 35% hydrogen peroxide, 1g of TS-1 titanium silicate molecular sieve catalyst, 0.2g of sodium dodecylbenzenesulfonate, and 0.5g of ethylene glycol were added to a batch reactor. The mixture was heated to 45°C under stirring and reacted for 2 hours. After the reaction, a small amount of the reaction solution was analyzed by gas chromatography and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 99.2%, the hydrogen peroxide utilization rate was 96%, and the selectivity for epichlorohydrin was 98.2%.

[0061] Example 2

[0062] In a batch reactor, 40g of allyl chloride, 12g of 50% hydrogen peroxide, 1.5g of TS-1 titanium silicate molecular sieve catalyst, 2.5g of potassium cetyl phosphate, and 5g of polyethylene glycol 200 were added. The mixture was heated to 80℃ with stirring and reacted for 3 hours. After the reaction, a small amount of the reaction solution was analyzed by gas chromatography 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 98.3%.

[0063] Examples 3-11

[0064] 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.

[0065] Table 1. Raw material composition, ratio, reaction conditions, and reaction results of Examples 3-11

[0066]

[0067]

[0068] In other embodiments, the test results for epichlorohydrin were similar to those described above, yielding products containing epichlorohydrin.

[0069] Example 12

[0070] In a batch reactor, 30g of allyl chloride, 5g of 35% hydrogen peroxide, 1.0g of titanium silicate molecular sieve TS-1 catalyst, 2g of sodium dodecylbenzenesulfonate, and 5g of ethylene glycol were added. The mixture was heated to 50℃ with stirring and reacted for 2 hours. After the reaction, a small amount of the reaction solution was analyzed by gas chromatography and titrated with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 98.2%, the hydrogen peroxide utilization rate was 96%, and the epichlorohydrin selectivity was 96.4%.

[0071] Comparative Example 1

[0072] In comparison, the same reaction conditions as in Example 12 were used, but without the addition of surfactants and polyols. The specific operation was as follows: 30g of allyl chloride, 5g of 35% hydrogen peroxide, and 1.0g of titanium silicate molecular sieve TS-1 catalyst were added to a batch reactor. After addition, a two-phase mixture of water and oil was formed; after stirring, it became a turbid liquid. The temperature was raised to 50°C under stirring, and the reaction time was 2 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 45.2%, the hydrogen peroxide utilization rate was 52%, and the epichlorohydrin selectivity was 89.2%.

[0073] Example 13

[0074] In a batch reactor, 20g of allyl chloride, 3g of 30% hydrogen peroxide, 1g of TS-1 titanium silicate molecular sieve catalyst, 2g of cetyl phosphate, and 5g of polyethylene glycol 200 were added. The mixture was heated to 60℃ with stirring and reacted for 2 hours. After the reaction, a small amount of the reaction solution was analyzed by gas chromatography and titration of hydrogen peroxide with cerium sulfate. The results showed that the hydrogen peroxide conversion rate was 97.5%, the hydrogen peroxide utilization rate was 98%, and the selectivity for epichlorohydrin was 96.2%.

[0075] Comparative Example 2

[0076] Using the same reaction conditions as in Example 13, but without the addition of ionic surfactants and polyols, and instead adding the organic phase methanol, the specific operation was as follows: 20g of allyl chloride, 3g of 30% hydrogen peroxide, 1g of TS-1 titanium silicate molecular sieve catalyst, and 50g of methanol were added to a batch reactor. The mixture was heated to 60°C under stirring, and the reaction time was 2 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 85.3%, the hydrogen peroxide utilization rate was 89%, and the epichlorohydrin selectivity was 92.3%.

[0077] 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 preparing epichlorohydrin, characterized in that, At least the following steps are included: A mixture containing allyl chloride, hydrogen peroxide, polyol, catalyst and ionic surfactant is reacted in a batch reactor to obtain a product containing epichlorohydrin. The catalyst contains titanium-silicon molecular sieve TS-1; The polyol is selected from at least one of ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, polyethylene glycol 200, polyethylene glycol 400, 1,4-cyclohexanediol, and glycerol. The ionic surfactant is selected from anionic surfactants; The molar ratio of hydrogen peroxide to ionic surfactant is 1~50:1; 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 mass of the catalyst is 0.1 to 10 wt% of the mass of chloropropylene.

2. 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.

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

4. The method according to claim 1, characterized in that, The molar ratio of hydrogen peroxide to ionic surfactant is 30~50:1; 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.

5. The method according to claim 1, characterized in that, The reaction temperature is 20~90℃.

6. The method according to claim 1, characterized in that, The reaction time is 1 to 10 hours.

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