Supercritical carbon dioxide assisted epoxidation of chlorinated olefins

Abstract

The present invention provides a method for supercritical carbon dioxide-assisted chloroolefin epoxidation reaction, the method comprising: under the action of a catalyst, chloroolefin in a composition containing carbon dioxide and hydrogen peroxide undergo epoxidation reaction, the carbon dioxide presents a supercritical state during the reaction, and the epoxidation reaction conditions are: reaction temperature 31.0-31.3°C, reaction pressure 7.38-7.42MPa. The present invention assists chloroolefin epoxidation reaction by forming supercritical carbon dioxide, which can significantly reduce the amount of solvent methanol or not use methanol, while ensuring a high conversion rate during the reaction process, and because a small amount of methanol or no methanol is used, the amount of extraction agent used in the separation process and the energy consumption and time consumption in the distillation process are reduced; at the same time, the occurrence of etherification reaction between epoxide and methanol is reduced or avoided; in addition, in this process, carbon dioxide is automatically released from the reaction liquid after the reaction, and can be further compressed and recycled, and the process is green and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of fine chemical products, and in particular to a method for epoxidation of chloroolefins assisted by supercritical carbon dioxide. Background Art

[0002] Epichlorohydrin and methyl epichlorohydrin are both very important organic chemical synthesis raw materials and chemical intermediates. Their molecular structures contain chlorine atoms and epoxy groups, and their chemical properties are very active. They are widely used in the synthesis of epichlorohydrin rubber, surfactants, epoxy resins and other fields.

[0003] At present, the main method for producing epichlorohydrin and methyl epichlorohydrin is the chlorohydrin process, but the chlorohydrin process has problems such as great environmental damage and complicated production process. The direct oxidation of allyl chloride or methyl allyl chloride with hydrogen peroxide to synthesize the corresponding epoxidation product has the advantages of high atomic utilization and less environmental pollution, so it has become a hot spot and focus of research.

[0004] Titanium silicate molecular sieve (TS-1) is a new type of heteroatom molecular sieve, belonging to the orthorhombic crystal system, and has the same MFI topological structure as ZSM-5 molecular sieve. The introduction of transition metal titanium gives TS-1 unique catalytic oxidation performance. The catalytic system composed of TS-1 molecular sieve and hydrogen peroxide is widely used in the field of selective oxidation and has excellent selective oxidation reaction performance. The use of TS-1 molecular sieve in the oxidation reaction of organic matter avoids the problems of complex oxidation process and environmental pollution. It has the unparalleled advantages of energy saving, economy and environmental friendliness over traditional oxidation systems, and is considered a milestone in zeolite catalysis in the 1980s.

[0005] Hydrogen peroxide is a recognized green oxidant, and its only oxidation byproduct is water. In the late 1970s, people discovered that TS-1 could be used as a catalyst for propylene epoxidation, and since then, TS-1 has opened the prelude to olefin epoxidation catalyzed by hydrogen peroxide as an oxidant. The TS-1 / H2O2 system has mild reaction conditions, high atomic utilization, safe process, less environmental pollution, and simple process. It is a new green chemical process with broad application prospects.

[0006] For the epoxidation of allyl chloride and methyl allyl chloride by hydrogen peroxide oxidation, methanol is mostly used as solvent. For example, patent CN 107308981 A discloses the epoxidation reaction conditions of allyl chloride using methanol as solvent, wherein the feed molar ratio of 3-chloropropene to hydrogen peroxide is 1-10:1, and the feed molar ratio of methanol to 3-chloropropene is 1-20:1, and the mass ratio of methanol to H2O2 is calculated to be 0.98-188:1. Patent CN111978273A also discloses a continuous synthesis process of epichlorohydrin by hydrogen peroxide method using methanol as solvent, and the molar ratio of methanol to hydrogen peroxide is 1-5:1.

[0007] However, in the epoxidation reaction of allyl chloride and methyl allyl chloride with methanol as solvent, it is extremely difficult to separate the solvent methanol from the raw material chloroolefin, and the product epoxide will react with the solvent methanol and water during direct distillation. Therefore, the epoxidation reaction material is not suitable for direct distillation purification. Patent CN 112957770A discloses a method for separating the epoxidation product of allyl chloride by extraction. First, the reaction material is separated into two phases by adding an extractant water. Since the aqueous phase contains a large amount of solvent, it needs to be further extracted with allyl chloride to reduce the loss of the product epichlorohydrin. Patent CN 101486690B further describes the separation method of the epoxidation reaction material of allyl chloride. By reducing the amount of methanol used in the reaction process, the material after the reaction is directly divided into an oil phase and an aqueous phase. The oil phase contains allyl chloride and epichlorohydrin and a small amount of methanol and water. The aqueous phase contains most of the methanol and a small amount of the product. The product is extracted with allyl chloride, mixed with the above-mentioned oil phase and distilled to obtain the raw material allyl chloride and the product, and the methanol in the aqueous phase is recovered by distillation. It can be seen that the greater the content of solvent methanol, the more epichlorohydrin will be contained in the aqueous phase during the extraction and separation process, and more allyl chloride will be required to extract the product, and the organic phase and the aqueous phase will require greater energy and time consumption to complete the distillation process. However, since allyl chloride is almost insoluble in water, the conversion rate of the epoxidation reaction using little methanol or no methanol as a solvent is extremely low.

[0008] The current research direction gradually turns to the reaction process of synthesizing β-methyl epichlorohydrin by TS-1 catalyzing β-methyl chloride under solvent-free conditions. Among them, patent CN 106967013A reports a method for preparing β-methyl epichlorohydrin in a Sc-CO2 system, which is to use Sc-CO2 as a solvent, mix with hydrogen peroxide, adjust the pH value with buffer ammonium carbonate, and then add β-methyl chloride propene as both a raw material and a co-solvent, and enter a tubular fixed bed reactor filled with Ti-MWW titanium silicon molecular sieve catalyst for epoxidation reaction, and the product is distilled to obtain β-methyl epichlorohydrin. However, the supercritical carbon dioxide state is not formed in this patent, and ammonium carbonate is additionally added. The presence of ammonium salt undoubtedly brings new impurities to the reaction system, and the nitrogen element will have a negative impact on the performance of the titanium silicon molecular sieve. Summary of the invention

[0009] In order to solve the problems of using a large amount of methanol as a reaction solvent, difficulty in product separation, and low raw material conversion rate in the prior art, the present invention provides a method for supercritical carbon dioxide-assisted epoxidation of chloroolefins. This method can significantly reduce the amount of solvent methanol or eliminate the use of methanol, while ensuring that the reaction process has a high conversion rate and low energy consumption and time consumption, and the process is green and environmentally friendly.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0011] In a first aspect, the present invention provides a method for epoxidation of chloroolefins assisted by supercritical carbon dioxide, comprising: in the presence of a catalyst, epoxidation of chloroolefins with hydrogen peroxide in a composition containing carbon dioxide, wherein the carbon dioxide is in a supercritical state during the reaction, and the epoxidation reaction conditions are: reaction temperature of 31.0 to 31.3° C. and reaction pressure of 7.38 to 7.42 MPa.

[0012] In some embodiments of the present invention, the catalyst is selected from titanium silicalite molecular sieve, preferably titanium silicalite molecular sieve with MFI topology.

[0013] In some embodiments of the present invention, the mass percentage of the carbon dioxide in the composition is 90-100%; preferably, the carbon dioxide is continuously pumped into the reaction system.

[0014] In some embodiments of the present invention, the composition further contains methanol, and the mass percentage of the methanol in the composition does not exceed 10%; preferably, the methanol is mixed with the hydrogen peroxide and then introduced into the reaction system.

[0015] In some embodiments of the present invention, the chlorinated olefin is allyl chloride or methyl allyl chloride; preferably, the chlorinated olefin is continuously pumped into the reaction system; preferably, the mass space velocity of the chlorinated olefin is 0.3 to 1.0 h -1 .

[0016] In some embodiments of the present invention, the mass concentration of the hydrogen peroxide is not less than 50%; preferably, the hydrogen peroxide is continuously pumped into the reaction system.

[0017] In a preferred embodiment of the present invention, in the reaction system, the mass ratio of H2O2, chloroolefin and CO2 in hydrogen peroxide is: H2O2: chloroolefin: CO2 = 1: 3-8: 2-5.

[0018] In some specific embodiments of the present invention, the composition containing carbon dioxide consists of 100% supercritical carbon dioxide, and the method comprises:

[0019] The catalyst is loaded into a jacketed reaction tube, wherein the upper and lower ends of the jacketed reaction tube are filled with inert quartz sand;

[0020] Chloroolefins, hydrogen peroxide and carbon dioxide are continuously pumped into the reaction system, and the epoxidation reaction conditions are controlled as follows: reaction temperature 31.0-31.3° C., reaction pressure 7.38-7.42 MPa.

[0021] In another specific embodiment of the present invention, the composition containing carbon dioxide consists of supercritical carbon dioxide and methanol. Preferably, the weight percentage of methanol in the composition does not exceed 10%. The method comprises:

[0022] The catalyst is loaded into a jacketed reaction tube, wherein the upper and lower ends of the jacketed reaction tube are filled with inert quartz sand;

[0023] mixing hydrogen peroxide and methanol to obtain a mixed solution;

[0024] The chloroolefin, the mixed solution and carbon dioxide are respectively continuously pumped into the reaction system, and the epoxidation reaction conditions are controlled as follows: reaction temperature 31.0-31.3° C., reaction pressure 7.38-7.42 MPa.

[0025] In the above two specific embodiments, preferably, in the reaction system, the mass ratio of H2O2, chloroolefin and CO2 in hydrogen peroxide is: H2O2: chloroolefin: CO2 = 1: 3-8: 2-5.

[0026] The present invention assists chloroolefins in epoxidation reaction by forming supercritical carbon dioxide, which can significantly reduce the amount of solvent methanol or eliminate the use of methanol, while ensuring a high conversion rate in the reaction process. In addition, since a smaller amount of methanol is used or no methanol is used, the amount of extractant used in the separation process and the energy consumption and time consumption in the distillation process can be reduced; at the same time, the occurrence of etherification reaction between epoxide and methanol can be reduced or avoided; in addition, in this process, carbon dioxide is automatically released from the reaction liquid after the reaction, and can be further compressed and recycled, and the process is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a chloroolefin epoxidation reaction device; wherein, 1-feed pump one, 2-feed pump two, 3-feed pump three, 4-feed valve one, 5-feed valve two, 6-feed valve three, 7-reactor, 8-filter, 9-pressure gauge one, 10-back pressure valve, 11-exhaust valve, 12-pressure gauge two.

[0028] Figure 2 This is the XRD spectrum of titanium silicalite molecular sieve. DETAILED DESCRIPTION

[0029] In the description of the present invention, it should be noted that, if the specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, which are intended to explain the present invention rather than to limit it.

[0031] The purity of the materials used in the examples is not less than 99%.

[0032] In order to better illustrate the present invention, the preparation process of titanium silicate molecular sieve is described, but it is not limited to the titanium silicate molecular sieve prepared by the following method.

[0033] Preparation method of titanium silicon molecular sieve TS-1: using silica sol as silicon source, tetrabutyl titanate as titanium source, and tetrapropylammonium bromide as template, crystallizing at 150-200°C for 12-48h, filtering, washing, drying, and calcining to obtain titanium silicon molecular sieve. This preparation method is currently a prior art and will not be described in detail here. The XRD spectrum of the titanium silicon molecular sieve TS-1 used in the embodiment of the present invention is shown in the attached Figure 2 .

[0034] The epoxidation index of chloroolefins is the H2O2 conversion rate (X H2O2 ) and epoxidation product selectivity. The reaction index is calculated as follows:

[0035] H2O2 conversion rate X = number of moles of H2O2 reacted / total number of moles of H2O2 × 100%;

[0036] Epichlorohydrin Selective S ECH = Number of moles of epichlorohydrin produced by the reaction / number of moles of H2O2 reacted × 100%.

[0037] Methyl epichlorohydrin selective S MECH = Number of moles of methyl epichlorohydrin produced by the reaction / Number of moles of H2O2 reacted × 100%

[0038] The molar number of H2O2 was determined by iodine titration, and the molar number of epichlorohydrin and methyl epichlorohydrin generated by the reaction was obtained by gas chromatography. The gas chromatograph model was Shimadzu GC-2014C, the gas chromatograph column model was DB-1701, and the heating program was a starting temperature of 50°C, maintained for 10 minutes, and heated to 230°C at a rate of 15°C / min, and maintained for 10 minutes.

[0039] The XRD characterization of the catalyst was measured by X-ray diffraction analyzer (PANalytical, X'Pert3 Powder).

[0040] Example 1

[0041] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, 50% hydrogen peroxide and liquid carbon dioxide were simultaneously introduced into the reaction system through double plunger pumps. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of 50% hydrogen peroxide was 1.3 g / h, and the feed rate of carbon dioxide was 2 g / h. After 24 hours of reaction, samples were taken for analysis. The reaction results are shown in Table 1.

[0042] See the attached schematic diagram of the epoxidation reaction device. Figure 1 .

[0043] Example 2

[0044] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, 50% hydrogen peroxide and liquid carbon dioxide were simultaneously introduced into the reaction system through double plunger pumps. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of 50% hydrogen peroxide was 1.3 g / h, and the feed rate of carbon dioxide was 2.7 g / h. After 24 hours of reaction, samples were taken for analysis. The reaction results are shown in Table 1.

[0045] Example 3

[0046] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, 50% hydrogen peroxide and liquid carbon dioxide were simultaneously introduced into the reaction system through double plunger pumps. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of 50% hydrogen peroxide was 0.9 g / h, and the feed rate of carbon dioxide was 1.8 g / h. After 24 hours of reaction, samples were taken for analysis. The reaction results are shown in Table 1.

[0047] Example 4

[0048] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, 50% hydrogen peroxide and liquid carbon dioxide were simultaneously introduced into the reaction system through double plunger pumps. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of 50% hydrogen peroxide was 2 g / h, and the feed rate of carbon dioxide was 4 g / h. After 24 hours of reaction, samples were taken for analysis. The reaction results are shown in Table 1.

[0049] Example 5

[0050] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, a mixture of 50% hydrogen peroxide and methanol, and liquid carbon dioxide were simultaneously introduced into the reaction system through a double plunger pump. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of a mixture of 50% hydrogen peroxide and methanol was 1.5 g / h (methanol accounted for 13.33%), and the feed rate of carbon dioxide was 2.7 g / h. After 24 hours of reaction, sampling and analysis were performed. The reaction results are shown in Table 1.

[0051] Example 6

[0052] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, a mixture of 50% hydrogen peroxide and methanol, and liquid carbon dioxide were simultaneously introduced into the reaction system through a double plunger pump. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of a mixture of 50% hydrogen peroxide and methanol was 1.6 g / h (methanol accounted for 18.75%), and the feed rate of carbon dioxide was 2 g / h. After 24 hours of reaction, sampling and analysis were performed. The reaction results are shown in Table 1.

[0053] Example 7

[0054] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials of allyl chloride, a mixture of 50% hydrogen peroxide and methanol, and liquid carbon dioxide were simultaneously introduced into the reaction system through a double plunger pump. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of allyl chloride was 3 g / h, the feed rate of a mixture of 50% hydrogen peroxide and methanol was 1.1 g / h (methanol accounted for 18.18%), and the feed rate of carbon dioxide was 1.3 g / h. After 24 hours of reaction, sampling and analysis were performed. The reaction results are shown in Table 1.

[0055] Example 8

[0056] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials methyl allyl chloride, 50% hydrogen peroxide, and liquid carbon dioxide were simultaneously introduced into the reaction system through a double plunger pump. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The methyl allyl chloride feed rate was 4.5 g / h, the 50% hydrogen peroxide feed rate was 2.25 g / h, and the carbon dioxide feed rate was 5.6 g / h. After the reaction was carried out for 24 hours, sampling and analysis were performed. The reaction results are shown in Table 2.

[0057] Example 9

[0058] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials methyl allyl chloride, a mixture of 50% hydrogen peroxide and methanol, and liquid carbon dioxide were simultaneously introduced into the reaction system through a double plunger pump. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of methyl allyl chloride was 4.5 g / h, the feed rate of a mixture of 50% hydrogen peroxide and methanol was 1.9 g / h (methanol accounted for 10.53%), and the feed rate of carbon dioxide was 3.4 g / h. After 24 hours of reaction, sampling and analysis were performed. The reaction results are shown in Table 2.

[0059] Comparative Example 1

[0060] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw material propylene chloride and the mixed solution of 50% hydrogen peroxide and methanol were simultaneously introduced into the reaction system through double plunger pumps. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. by a constant temperature water bath. The feed rate of propylene chloride was 3 g / h, and the feed rate of the mixed solution of 50% hydrogen peroxide and methanol was 1.6 g / h. After the reaction was carried out for 24 hours, samples were taken for analysis. The reaction results are shown in Table 1.

[0061] Comparative Example 2

[0062] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw material methyl allyl chloride and the mixed solution of 50% hydrogen peroxide and methanol were simultaneously introduced into the reaction system through a double plunger pump. The reaction pressure was 7.38-7.42 MPa. The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The feed rate of methyl allyl chloride was 4.5 g / h, and the feed rate of the mixed solution of 50% hydrogen peroxide and methanol was 1.9 g / h. After 24 hours of reaction, samples were taken for analysis. The reaction results are shown in Table 2.

[0063] Comparative Example 3

[0064] This comparative example adopts the reaction temperature and reaction pressure of Example 1 in CN 106967013A, and is verified in combination with the operation method of Example 1 of the present invention:

[0065] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials methallyl chloride, 50% hydrogen peroxide, and liquid carbon dioxide were respectively introduced into the reaction system simultaneously through a double plunger pump. The reaction pressure was 7.6 MPa (fluctuation did not exceed 0.2 MPa). The reaction temperature was maintained at 45° C. (fluctuation did not exceed 0.2° C.) in a constant temperature water bath. The methallyl chloride feed rate was 4.5 g / h, the 50% hydrogen peroxide feed rate was 2.25 g / h, and the carbon dioxide feed rate was 5.6 g / h. After the reaction was carried out for 24 hours, sampling and analysis were performed. The reaction results are shown in Table 2.

[0066] Comparative Example 4

[0067] 6 g (20-40 mesh) of catalyst was loaded into the middle section of the jacketed reaction tube. The upper and lower ends of the reaction tube were filled with inert quartz sand. The raw materials methyl allyl chloride, 50% hydrogen peroxide, and liquid carbon dioxide were respectively introduced into the reaction system simultaneously through a double plunger pump. The reaction pressure was 6.5 MPa (the fluctuation did not exceed 0.2 MPa). The reaction temperature was maintained at 31.0-31.3° C. in a constant temperature water bath. The methyl allyl chloride feed rate was 4.5 g / h, the 50% hydrogen peroxide feed rate was 2.25 g / h, and the carbon dioxide feed rate was 5.6 g / h. After the reaction was carried out for 24 hours, sampling and analysis were performed. The reaction results are shown in Table 2.

[0068] Table 1 Epoxidation results of allyl chloride

[0069]

[0070]

[0071] Table 2 Results of epoxidation of methyl allyl chloride

[0072] Serial number <![CDATA[X H2O2 (%)]]> <![CDATA[S MECH (%)]]> Example 8 99.2 99.0 Example 9 99.7 98.3 Comparative Example 2 33.5 99.9 Comparative Example 3 84.5 96.4 Comparative Example 4 80.0 97.4

[0073] Since the product was not purified separately in the pilot experiment but was purified by mixing multiple batches, the final yield data is not given. However, from the results in Table 1 and Table 2, the present invention has initially achieved success in assisting the epoxidation reaction of chloroolefins by forming supercritical carbon dioxide.

[0074] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for epoxidation of chloroolefins assisted by supercritical carbon dioxide, characterized in that: The method comprises: The catalyst is loaded into a jacketed reaction tube, wherein the upper and lower ends of the jacketed reaction tube are filled with inert quartz sand; Chloroolefin, hydrogen peroxide and carbon dioxide are respectively continuously pumped into the reaction system, and the epoxidation reaction conditions are controlled as follows: reaction temperature 31.0-31.3°C, reaction pressure 7.38-7.42Mpa; during the reaction, the carbon dioxide is in a supercritical state; The catalyst is a titanium silicon molecular sieve having an MFI topological structure; The chlorinated olefin is allyl chloride or methallyl chloride; The hydrogen peroxide is continuously pumped into the reaction system; In the reaction system, the mass ratio of H2O2, chloroolefin and CO2 in hydrogen peroxide is: H2O2: chloroolefin: CO2 = 1: 3~8: 2~5.

2. The method for epoxidation of chloroolefins assisted by supercritical carbon dioxide according to claim 1, characterized in that: The carbon dioxide is continuously pumped into the reaction system.

3. The method for epoxidation of chloroolefins assisted by supercritical carbon dioxide according to claim 1, characterized in that: The chloroolefin is continuously pumped into the reaction system.

4. The method for epoxidation of chloroolefins assisted by supercritical carbon dioxide according to claim 3, characterized in that: The mass space velocity of the chlorinated olefin is 0.3 to 1.0 h -1 .

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