Process for the direct oxidation of chloropropene to epichlorohydrin

Abstract

The application discloses a process for preparing epichlorohydrin by directly oxidizing chloropropene, which comprises the following steps: passing a homogeneous mixture containing chloropropene, hydrogen peroxide, polyhydric alcohol and non-ionic surfactant into a fixed bed reactor to carry out 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 process 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 (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. The propylene process is the main production method for epichlorohydrin (ECH), followed by the glycerol process. However, both methods have certain drawbacks. The glycerol process offers advantages such as mild reaction conditions, high selectivity and yield, and significantly reduced waste compared to the propylene process. However, with the continuous release of new domestic glycerol-based epichlorohydrin production capacity, the demand for glycerol continues to increase, leading to a sharp rise in the cost of the glycerol process. This results in a high-cost, low-profit situation for epichlorohydrin, and even losses in some stages. Meanwhile, with increasingly stringent environmental and safety requirements, the hydrogen peroxide process for synthesizing epichlorohydrin has gained increasing attention as a novel, environmentally friendly method.

[0003] 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 evaporation and recovery, thus hindering the industrialization of this process. Summary of the Invention

[0004] According to one aspect of this application, a method for preparing epichlorohydrin is provided. The method includes adding a nonionic surfactant and a polyol to a reaction system to form a homogeneous mixture of allyl chloride and hydrogen peroxide. The mixture is then pumped into a fixed-bed reactor containing a titanium silicate molecular sieve TS-1 via a metering pump to obtain the epichlorohydrin. This method promotes the mixing of the organic and aqueous phases by adding a nonionic 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-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.

[0005] At least the following steps are included:

[0006] A homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol, and nonionic surfactant is fed into a fixed-bed reactor to react and obtain a product containing epichlorohydrin.

[0007] The fixed-bed reactor is filled with a catalyst containing titanium-silicon molecular sieve TS-1;

[0008] Nonionic surfactants and polyols are added to the reaction system to form a homogeneous phase between allyl chloride and hydrogen peroxide, which is then pumped into a fixed-bed reactor containing titanium-silicon molecular sieve TS-1 by a metering pump.

[0009] 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.

[0010] 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).

[0011] The reaction temperature is 20–90°C;

[0012] 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.

[0013] The feed mass hourly space velocity (HHSV) for the reaction is 0.5–10 h⁻¹. -1 .

[0014] 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.

[0015] The molar ratio of allyl chloride to polyol is 5 to 10:1.

[0016] 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.

[0017] Optionally, the molar ratio of allyl chloride to polyol is 6 to 10:1;

[0018] Optionally, the molar ratio of the chloropropene to the polyol is 8 to 10:1.

[0019] The molar ratio of allyl chloride to hydrogen peroxide is 1 to 10:1.

[0020] 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.

[0021] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 3 to 10:1;

[0022] Optionally, the molar ratio of allyl chloride to hydrogen peroxide is 5 to 10:1.

[0023] The molar ratio of hydrogen peroxide to nonionic surfactant is 1 to 50:1.

[0024] 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.

[0025] Optionally, the molar ratio of hydrogen peroxide to nonionic surfactant is 10 to 50:1;

[0026] Optionally, the molar ratio of hydrogen peroxide to nonionic surfactant is 30 to 50:1.

[0027] The hydrogen peroxide has a mass concentration of 10-70%.

[0028] 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.

[0029] The titanium-silicon molecular sieve TS-1 is a titanium-doped silicon-based zeolite molecular sieve.

[0030] The titanium-silicon molecular sieve TS-1 has an MFI-type topology.

[0031] 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.

[0032] 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);

[0033] 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);

[0034] 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);

[0035] The polyoxyethylene fatty alcohol ether (Brij) is selected from at least one of Brij15, Brij20, Brij30 or Brij35;

[0036] The nonylphenol polyoxyethylene ether (NP) is selected from at least one of NP-5, NP-7, NP-9 or NP-10.

[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. In a fixed-bed 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.

[0039] (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.

[0040] (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.

[0041] (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

[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, NP-10, 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:nonionic surfactant of 50:5:1:6. The temperature was raised to 45°C. After the reaction was completed, 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 98.2%, the hydrogen peroxide utilization rate was 97%, and the epichlorohydrin selectivity was 98.6%.

[0050] Example 2

[0051] Using a metering pump at an air velocity of 3.0 h -1 A mixed solution of allyl chloride, 30% hydrogen peroxide, Tween 20, 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:nonionic surfactant of 100:10:1:23, and the temperature was raised to 70°C. After the reaction, a small amount of the reaction solution was analyzed by gas chromatography and titrated with cerium sulfate to obtain hydrogen peroxide. The results showed that the hydrogen peroxide conversion rate was 98.5%, the hydrogen peroxide utilization rate was 98%, and the selectivity for epichlorohydrin was 99.2%.

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

[0057] Example 12

[0058] Using a metering pump at an air velocity of 3.0 h -1 A mixed solution of allyl chloride, 30% hydrogen peroxide, NP-7, 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:nonionic surfactant:polyol of 50:5:1:5, and heated 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 97.5%.

[0059] Comparative Example 1

[0060] Using the same reaction conditions as in Example 12, but without adding a surfactant, the specific operation was as follows: a metering pump was used at a space velocity of 3.0 h⁻¹. -1 A mixed solution of allyl chloride and 30% 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. Initially, the mixture was 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 77.2%, the hydrogen peroxide utilization rate was 65%, and the selectivity for epichlorohydrin was 91.8%.

[0061] Example 13

[0062] Using a metering pump at an air velocity of 10.0 h -1 A mixed solution of allyl chloride, 50% hydrogen peroxide, Brij35, 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:nonionic surfactant:polyol of 10:3:1:1. 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 97.8%, the hydrogen peroxide utilization rate was 98%, and the selectivity for epichlorohydrin was 97.3%.

[0063] Comparative Example 2

[0064] Using the same reaction conditions as in Example 13, but without adding nonionic 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 10.0 h⁻¹. -1 A mixed solution of allyl chloride, 50% 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 10:3:50. 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 89.1%, the hydrogen peroxide utilization rate was 93%, and the selectivity for epichlorohydrin was 93.7%.

[0065] 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 the direct oxidation of allyl chloride to prepare epichlorohydrin, characterized in that, At least the following steps are included: A homogeneous mixture containing allyl chloride, hydrogen peroxide, polyol, and nonionic surfactant is fed into a fixed-bed reactor to react and obtain a product containing epichlorohydrin. 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, 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 hydrogen peroxide has a mass concentration of 10-70%.

2. The method according to claim 1, characterized in that, The feed mass hourly space velocity (HHSV) for the reaction is 0.5–10 h⁻¹. -1 .

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 3~10:1; The molar ratio of hydrogen peroxide to nonionic 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 nonionic surfactant is 30~50:

1.

5. 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; The fatty acid glyceride is selected from at least one of triglyceride, triglyceride, or triglyceride; The fatty acid sorbitan is selected from at least one of Span 20, Span 40, Span 60, Span 65, Span 80 or Span 85; The polysorbate is selected from at least one of Tween 20, Tween 40, Tween 60, Tween 65, Tween 80 or Tween 85; The polyoxyethylene fatty alcohol ether is selected from at least one of Brij15, Brij20, Brij30 or Brij35; The nonylphenol polyoxyethylene ether is selected from at least one of NP-5, NP-7, NP-9 or NP-10.

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