A synthesis method for preparing epichlorohydrin by directly oxidizing chloropropene

Abstract

The application discloses a process for preparing epichlorohydrin by directly oxidizing chloropropene, which comprises the following steps: feeding a homogeneous mixture containing chloropropene, hydrogen peroxide, polyhydric alcohol and non-ionic surfactant into a continuous reactor to perform reaction, and obtaining a product containing epichlorohydrin. Compared with the traditional method, the reaction byproduct is less, the product after hydrogen peroxide reaction is water, the non-ionic surfactant and 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 selectivity are high, the process is suitable for large-scale industrial production, 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 epichlorohydrin can be efficiently produced.

Description

Technical Field

[0001] This application relates to a synthetic method for the direct oxidation of allyl chloride to prepare epichlorohydrin, using 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, which belongs 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 have 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.

[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] However, current processes typically use a significant amount of solvent to dissolve the reactants allyl chloride and hydrogen peroxide to form a homogeneous phase. If the solvent is insufficient, the two phases cannot be fully dissolved, hindering mass and heat transfer, increasing the occurrence of 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 in several ways. Summary of the Invention

[0005] According to one aspect of this application, a method for preparing epichlorohydrin is provided. This method involves introducing a nonionic surfactant and a polyol into 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 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 promotes the mixing of the organic and aqueous phases by adding nonionic surfactants and polyols, 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 nonionic 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 nonionic 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 nonionic surfactant is selected from at least one of alkyl glucoside (APG), fatty acid glycerides, fatty acid sorbitan (Span), polysorbate (Tween), polyoxyethylene fatty alcohol ether (Brij) and nonylphenol polyoxyethylene ether (NP).

[0012] The alkyl glucoside (APG) is selected from at least one of APG0810, APG0810-1214, APG0814, C12-18 alkyl glucoside, C20 alkyl glucoside, and lauryl alkyl glucoside.

[0013] The fatty acid glycerides are selected from at least one of trioleic acid esters (oleic acid), trioleic acid esters (palmitic acid), and trioleic acid esters (stearic acid);

[0014] The fatty acid sorbitan (Span) is selected from at least one of Span 20 (sorbitan lauryl), Span 40 (sorbitan palmitate), Span 60 (sorbitan stearate), Span 65 (sorbitan tristearate), Span 80 (sorbitan oleate), and Span 85 (sorbitan trioleate);

[0015] The polysorbate (Tween) is selected from at least one of Tween 20 (polysorbate 20), Tween 40 (polysorbate 40), Tween 60 (polysorbate 60), Tween 65 (polysorbate 65), Tween 80 (polysorbate 80) and Tween 85 (polysorbate 85);

[0016] The polyoxyethylene fatty alcohol ether (Brij) is selected from at least one of Brij15, Brij20, Brij30 or Brij35;

[0017] The nonylphenol polyoxyethylene ether (NP) is selected from at least one of NP-5, NP-7, NP-9 or NP-10.

[0018] The titanium-silicon molecular sieve TS-1 is a titanium-doped silicon-based zeolite molecular sieve.

[0019] The titanium-silicon molecular sieve TS-1 has an MFI-type topology.

[0020] The molar ratio of allyl chloride to polyol is 5 to 10:1.

[0021] 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.

[0022] Optionally, the molar ratio of allyl chloride to polyol is 6 to 10:1;

[0023] Optionally, the molar ratio of the chloropropene to the polyol is 8 to 10:1.

[0024] The molar ratio of allyl chloride to hydrogen peroxide is 1 to 10:1.

[0025] 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.

[0026] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 3 to 10:1;

[0027] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 5 to 10:1.

[0028] The molar ratio of hydrogen peroxide to nonionic surfactant is 1 to 50:1.

[0029] Optionally, the molar ratio of hydrogen peroxide to the nonionic 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.

[0030] Optionally, the molar ratio of hydrogen peroxide to nonionic surfactant is 10 to 50:1;

[0031] Optionally, the molar ratio of hydrogen peroxide to nonionic surfactant is 30 to 50:1.

[0032] The hydrogen peroxide has a mass concentration of 10-70%.

[0033] 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.

[0034] The reaction temperature is 20–90°C;

[0035] 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.

[0036] The reaction time is 1 to 10 hours;

[0037] 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.

[0038] The liquid flow rate of the reaction is 0.1 L / min to 20 L / min.

[0039] 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.

[0040] The beneficial effects that this application can produce include:

[0041] (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 continuous reactor, chloropropylene is directly oxidized to epichlorohydrin. There are fewer reaction by-products. The product after the hydrogen peroxide reaction is water, which has less environmental pollution and is green and environmentally friendly.

[0042] (2) 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 nonionic surfactants and polyols, thereby improving the selectivity of the reaction. It does not require the addition of a large amount of solvent in traditional processes, 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.

[0043] (3) 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, making it suitable for large-scale industrial production.

[0044] (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

[0045] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0046] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0047] The analysis method in the embodiments of this application is as follows:

[0048] 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.

[0049] The selectivity of epichlorohydrin and the utilization rate of hydrogen peroxide were determined by gas chromatography.

[0050] 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.

[0051] Example 1

[0052] Multiple metering pumps were used to pump allyl chloride, 30% hydrogen peroxide, nonionic surfactant NP-9, and polyethylene glycol 200 molar ratios of 50:5:1:10 into a continuous reactor containing a titanium-silicon molecular sieve TS-1 catalyst. The solution was passed through a heat exchanger at a flow rate of 5 L / min, heated to 40°C, and reacted continuously for 6 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 a hydrogen peroxide conversion rate of 97.8%, a hydrogen peroxide utilization rate of 98%, and an epichlorohydrin selectivity of 97.8%.

[0053] Example 2

[0054] 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: 20% hydrogen peroxide: nonionic surfactant Brij35: ethylene glycol of 100:10:1:20. The solution was passed through a heat exchanger at a flow rate of 15 L / min, heated to 60 °C, and reacted continuously for 10 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 96%, and the selectivity for epichlorohydrin was 95.6%.

[0055] Examples 3-11

[0056] 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.

[0057] Table 1. Raw material composition, ratio, reaction conditions, and reaction results of Examples 3-11

[0058]

[0059] The test results for epichlorohydrin in other embodiments are similar to those described above, and epichlorohydrin was obtained through this invention.

[0060] Example 12

[0061] 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: 30% hydrogen peroxide: Tween 20 (nonionic surfactant): glycerol of 50:5:1:5. The solution was passed through a heat exchanger at a flow rate of 15 L / min, and the temperature was raised to 35°C. The reaction was carried out 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 96.5%, the hydrogen peroxide utilization rate was 96%, and the selectivity for epichlorohydrin was 96.7%.

[0062] Comparative Example 1

[0063] 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 30% hydrogen peroxide of 50:5. The solution was passed through a heat exchanger at a flow rate of 15 L / min, and the temperature was raised to 35°C. The continuous reaction time was 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 73.5%, the hydrogen peroxide utilization rate was 73%, and the epichlorohydrin selectivity was 90.7%.

[0064] Example 13

[0065] 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: nonionic surfactant NP-10: polyethylene glycol 200 of 35:6:1:7. The solution was passed through a heat exchanger at a flow rate of 5 L / min, heated to 70°C, and reacted continuously for 4 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 96.8%, the hydrogen peroxide utilization rate was 98%, and the selectivity for epichlorohydrin was 97.9%.

[0066] Comparative Example 2

[0067] Using the same reaction conditions as in Example 13, but without the addition of nonionic surfactants and polyols, and instead adding 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 35:6:500. The solution was passed through a heat exchanger at a flow rate of 5 L / min, and the temperature was raised to 70°C. The continuous reaction time was 4 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 87.3%, the hydrogen peroxide utilization rate was 91%, and the epichlorohydrin selectivity was 93.4%.

[0068] 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 by direct oxidation of allyl chloride, characterized in that, At least the following steps are included: A homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol, and nonionic 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 and nonionic surfactant work synergistically to form a solvent-free homogeneous system; 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. The nonionic surfactant is selected from at least one of alkyl glucoside, fatty acid glyceride, fatty acid sorbitan, polysorbate, polyoxyethylene fatty alcohol ether or nonylphenol polyoxyethylene ether; 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 nonionic surfactant is 1~50:1; The reaction temperature is 20~90℃; The reaction time is 1 to 10 hours; The liquid flow rate of the reaction is 0.1 L / min to 20 L / min.

2. The method according to claim 1, characterized in that, The alkyl glucoside is selected from at least one of APG0810, APG0810-1214, APG0814, C12-18 alkyl glucoside, C20 alkyl glucoside, or lauryl alkyl glucoside.

3. The method according to claim 1, characterized in that, The fatty acid glycerides are selected from at least one of triglyceride, triglyceride, or tristearate.

4. The method according to claim 1, characterized in that, The fatty acid sorbitan is selected from at least one of Span 20, Span 40, Span 60, Span 65, Span 80 or Span 85.

5. The method according to claim 1, characterized in that, The polysorbate is selected from at least one of Tween 20, Tween 40, Tween 60, Tween 65, Tween 80 or Tween 85.

6. The method according to claim 1, characterized in that, The polyoxyethylene fatty alcohol ether is selected from at least one of Brij15, Brij20, Brij30 or Brij35.

7. The method according to claim 1, characterized in that, The nonylphenol polyoxyethylene ether is selected from at least one of NP-5, NP-7, NP-9 or NP-10.

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

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