A process for the preparation of epichlorohydrin

Abstract

The application discloses a process for preparing epichlorohydrin, which comprises the following steps: passing a homogeneous mixture containing chloropropene, hydrogen peroxide, polyhydric alcohol and ionic surfactant into a fixed bed reactor to react, and obtaining a product containing epichlorohydrin. Compared with the traditional method, the reaction by-product is less, the product after hydrogen peroxide reaction is water, the ionic surfactant and the polyhydric alcohol are added to promote the mixing of the organic phase and the aqueous phase into a homogeneous phase, improve the 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, the equipment process is simple, the yield and the selectivity are high, the process is suitable for large-scale production in industry, has great economic benefits, solvent evaporation and recovery are not needed, is beneficial to industrial production amplification, the equipment maintenance cost is low, the system cost is relatively low, the environmental pollution is small, the operation is simple, the process is easy to repeat, and the epichlorohydrin can be efficiently produced.

Description

Technical Field

[0001] This application relates to a process 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 key intermediate in the petrochemical industry. It is mainly used in the production of epoxy resins, glycerin, chlorohydrin rubber and other derivatives. It can also be used as a solvent, plasticizer, flame retardant and surfactant.

[0003] 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 capacity share, the glycerol method is the main one, the propylene method is the secondary one, and the hydrogen peroxide method has the lowest overall share.

[0004] 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".

[0005] The direct oxidation process for epichlorohydrin is a novel and environmentally friendly technology for producing epichlorohydrin, and it is poised to lead the future development of epichlorohydrin. 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 both 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 adding an ionic surfactant and a polyol to a reaction system to form a homogeneous mixture of allyl chloride and hydrogen peroxide (oil and water phases). The mixture is then pumped into a fixed-bed reactor containing a titanium silicate molecular sieve TS-1 via a metering pump, where allyl chloride is directly epoxidized to obtain the epichlorohydrin. This method promotes the mixing of the organic and aqueous phases by adding an ionic surfactant and a polyol, 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. The solvent-free synthesis system used in this method offers significant economic benefits, lower system costs, less 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 homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol and ionic surfactant is fed into a fixed-bed reactor to react and obtain a product containing epichlorohydrin.

[0009] The fixed-bed reactor is filled with a catalyst containing 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, or 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 zwitterionic surfactant is selected from at least one of lecithin-type, amino acid-type, and betaine-type zwitterionic surfactants.

[0017] The titanium-silicon molecular sieve TS-1 is a titanium-doped silicon-based zeolite molecular sieve.

[0018] The titanium-silicon molecular sieve TS-1 has an MFI-type topology.

[0019] The reaction temperature is 20–90°C;

[0020] 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.

[0021] The feed mass hourly space velocity (HHSV) for the reaction is 0.5–10 h⁻¹. -1 .

[0022] Optionally, the feed mass hourly space velocity of the reaction is independently selected from 0.5 h⁻¹. -1 1h -1 1.5h -1 2h -1 2.5h -1 3h -1 3.5h -1 4h -1 4.5h -1 5h -1 5.5h -1 6h -1 6.5h -1 7h -1 7.5h -1 8h -1 8.5h -1 9h -1 9.5h -1 or 10h -1 Any value in or any value between any two.

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

[0032] 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.

[0033] Optionally, the molar ratio of hydrogen peroxide to ionic surfactant is 10 to 50:1;

[0034] Optionally, the molar ratio of hydrogen peroxide to ionic surfactant is 30 to 50:1.

[0035] The hydrogen peroxide has a mass concentration of 10-70%.

[0036] 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.

[0037] The beneficial effects that this application can produce include:

[0038] (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.

[0039] (2) 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.

[0040] (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.

[0041] (4) The method for preparing epichlorohydrin provided in this application is energy-saving and environmentally friendly, with simple equipment and processes, high yield and selectivity of epichlorohydrin, and is suitable for large-scale industrial production of epichlorohydrin. The solvent-free synthesis system used in this method has great economic benefits. Detailed Implementation

[0042] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0043] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0044] The analysis method in the embodiments of this application is as follows:

[0045] 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.

[0046] The selectivity of epichlorohydrin and the utilization rate of hydrogen peroxide were determined by gas chromatography.

[0047] 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.

[0048] Example 1

[0049] Using a metering pump at an air velocity of 3.0 h -1 A mixed solution of allyl chloride, 30% hydrogen peroxide, sodium dodecylbenzenesulfonate, and polyethylene glycol 200 was pumped into a fixed-bed reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride:hydrogen peroxide:ionic surfactant of 50:5:1:5. The temperature was raised to 40°C. 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 93.1%, the hydrogen peroxide utilization rate was 94%, and the epichlorohydrin selectivity was 96.3%.

[0050] Example 2

[0051] Using a metering pump at an air velocity of 2.0 h⁻¹ -1 A mixed solution of allyl chloride, 35% hydrogen peroxide, sodium stearate, and ethylene glycol was pumped into a fixed-bed reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride:hydrogen peroxide:ionic surfactant of 100:10:1:10, and the temperature was raised to 65°C. 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%.

[0052] Examples 3-11

[0053] 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.

[0054] Table 1. Raw material composition, ratio, reaction conditions, and reaction results of Examples 3-11

[0055]

[0056]

[0057] The test results for epichlorohydrin in other embodiments are similar to those described above, and epichlorohydrin was obtained through this invention.

[0058] Example 12

[0059] Using a metering pump at an air velocity of 3.0 h -1 A mixed solution of allyl chloride, 45% hydrogen peroxide, sodium dodecylbenzenesulfonate, and hexanediol was pumped into a fixed-bed reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride:hydrogen peroxide:ionic surfactant:polyol of 50:5:1:2, and the temperature was raised to 50°C. 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 98.3%, the hydrogen peroxide utilization rate was 97%, and the selectivity for epichlorohydrin was 96.8%.

[0060] Comparative Example 1

[0061] Using the same reaction conditions as in Example 12, but without the addition of surfactants and polyols, the specific operation was as follows: a metering pump was used at a space velocity of 3.0 h⁻¹. -1A mixed solution of allyl chloride and 45% hydrogen peroxide was pumped into a fixed-bed reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride:hydrogen peroxide of 50:5. The temperature was raised to 50°C. After addition, the mixture formed a two-phase mixture of water and oil; after stirring, it became a turbid liquid. The temperature was raised to 50°C, and the reaction time was 1 hour. 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 82.5%, the hydrogen peroxide utilization rate was 72%, and the selectivity for epichlorohydrin was 85.4%.

[0062] Example 13

[0063] Using a metering pump at an air velocity of 10.0 h -1 A mixed solution of allyl chloride, 40% hydrogen peroxide, cetyl phosphate, and glycerol was pumped into a fixed-bed reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride:hydrogen peroxide:ionic surfactant:polyol of 10:1:1:1. The temperature was raised to 60°C, and the reaction time was 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 94.5%, the hydrogen peroxide utilization rate was 98%, and the selectivity for epichlorohydrin was 94.3%.

[0064] Comparative Example 2

[0065] Using the same reaction conditions as in Example 13, but without adding ionic surfactants and polyols, and instead adding the organic phase methanol, the specific operation was as follows: a metering pump was used at a space velocity of 8.0 h⁻¹. -1 A mixed solution of allyl chloride, 40% hydrogen peroxide, and methanol was pumped into a fixed-bed reactor containing a titanium-silicon molecular sieve TS-1 catalyst at a molar ratio of allyl chloride:hydrogen peroxide:methanol of 10:1:50. The temperature was raised to 60°C, and the reaction time was 3 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 89.3%, the hydrogen peroxide utilization rate was 92%, and the selectivity for epichlorohydrin was 91.3%.

[0066] 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 process for preparing epichlorohydrin, characterized in that, At least the following steps are included: A homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol and ionic surfactant is fed into a fixed-bed reactor to react and obtain a product containing epichlorohydrin. The reaction temperature is 20~90℃; The feed mass hourly space velocity (HHSV) for the reaction is 0.5–10 h⁻¹. -1 ; The fixed-bed 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, and trimethylolpropane. 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 3~10:1; The molar ratio of hydrogen peroxide to ionic surfactant is 1~50:

1.

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

1.

4. 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.

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

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