WO2019006993A1

WO2019006993A1 - Method for preparing perfluoroethyl isopropyl ketone

Info

Publication number: WO2019006993A1
Application number: PCT/CN2017/116479
Authority: WO
Inventors: 蔡星伟; 沙敏; 潘仁明; 姜标; 赵玉媛
Original assignee: 江苏科技大学; 江苏科技大学海洋装备研究院
Priority date: 2017-06-28
Filing date: 2017-12-15
Publication date: 2019-01-10
Also published as: CN107235834B; CN107235834A

Abstract

The present invention relates to a method for preparing perfluoroethyl isopropyl ketone, comprising: using perfluoro-4-methyl-2-amylene or a mixture of perfluoro-4-methyl-2-amylene and perfluoro-2-methyl-2-amylene as a raw material; firstly, converting perfluoro-4-methyl-2-amylene into perfluoro-2-methyl-2-amylene by means of an isomerization reaction; next, epoxidizing perfluoro-2-methyl-2-amylene as perfluoro-2-methyl-2,3-pentylene oxide; and then, enabling catalytic rearrangement of perfluoro-2-methyl-2,3-pentylene oxide to obtain perfluoroethyl isopropyl ketone. The present invention has the following advantages: the catalytic isomerization reaction in the present invention can be performed in a solvent-free condition so that the problems that a great number of toxic solvents are used in existing processes, recycling is difficult to be carried out and the like are avoided; tertiary amine nitrogen oxide or N,N-dialkyl hydroxylamine is used as an epoxidation reagent, such that perfluoro-2-methyl-2-amylene is quantitatively converted into perfluoro-2-methyl-2,3-pentylene oxide under a mild condition, and thus the problems that a great number of sodium hypochlorite solutions are used in existing processes so that devices are seriously corroded, a great number of salt solutions generated in post-treatment are difficult to be recycled, the use conditions are harsh and the like are avoided.

Description

Preparation method of perfluoroethyl isopropyl ketone

Technical field

The invention belongs to the technical field of preparation methods of perfluoroketone compounds in organic fluorine chemistry, and in particular relates to a preparation method of perfluoroethyl isopropyl ketone.

Background technique

Perfluoroethyl isopropyl ketone, also known as dodecafluoro-2-methylpentan-3-one, abbreviated as fluorenated ketone, has the formula CF ₃ CF ₂ C(O)CF(CF ₃ ) ₂ , The CAS number is 756-13-8. When used as a fire extinguishing agent, perfluoroethyl isopropyl ketone has low fire extinguishing concentration, high fire extinguishing efficiency, good environmental performance, low toxicity, good safety, little impact on related equipment and materials, no residue, easy storage and transportation. And a wide range of advantages, such as a wide range of applications. While ensuring high fire-extinguishing efficiency, it solves the environmental problems of the previous fluoroalkane halon substitutes. It is a true long-acting halon replacement product that has been used in fire extinguishing systems in important places or parts. With the reduction of production costs, its application fields will be expanded, and finally applied to the fire extinguishing systems of general industrial and civil buildings, which has broad development prospects.

In addition to being used as a fire extinguishing agent, perfluoroethyl isopropyl ketone can also be used as a protective gas, a cleaning agent and a solvent for smelting magnesium, or as a flame retardant added to various flammable working liquids to reduce or eliminate Its flammability.

The former Soviet Union synthesized perfluoroethyl isopropyl ketone in the 1970s, but did not achieve large-scale production. Until 2001, after 3M Company of the United States used it as a fire extinguishing agent to replace halons and fluoroalkanes, its synthesis and application research gradually gained people's attention.

U.S. Patent No. 6,478,979, B1 describes a process for the preparation of perfluoroethyl isopropyl ketone. Under anhydrous conditions, the aprotic polar solvent diglyme is used as the reaction medium, the active potassium fluoride is used as a catalyst, and hexafluoropropylene is added to the perfluoropropionyl fluoride to obtain a perfluoroethyl isopropyl group. ketone. The reaction temperature was 70 ° C and the pressure was 1 MPa. The obtained crude product contained 90.6% of perfluoroethyl isopropyl ketone and 0.37% of hexafluoropropylene dimer. The yield of the reaction to hexafluoropropylene was 98.8%, and the yield to perfluoropropionyl fluoride was 79.28%. A small amount of impurities such as trimer can be removed from perfluoroethyl isopropyl ketone by water washing, distillation and drying to obtain a perfluoroethyl isopropyl ketone containing hexafluoropropylene dimer 0.4% and having a purity of 99%. . The yield and selectivity of the reaction route are high, but the preparation of the raw material perfluoropropionyl fluoride is difficult, the reaction yield is low, and the cost is high, and the industrialization of the product has not been realized in China.

Vilenchik et al. (Zh. Khim, 1978, 23(2): 236-237) report a process for preparing perfluoroethyl isopropyl ketone starting from hexafluoropropylene. At 20 to 25 ° C, hexafluoropropylene is first oxidized to perfluoropropylene oxide with oxygen, and the latter is reacted with another molecule of hexafluoropropylene under the catalysis of cesium fluoride to obtain a perfluoroethyl isopropyl group. ketone. From the point of view of molecular utilization, the technical route is ideal, and both raw materials and oxidants are easily obtained, but the target product has poor selectivity and many side reactions. The crude product contained only 34.6% of perfluoroethyl isopropyl ketone, 42.6% of perfluoroethyl-n-hexanone and 8% of perfluoroethyl-n-decyl ketone, trimer and tetramerization of by-products. The body has more oxides. Zapevalov et al. (Izv. Akad. Nauk, 1979, (12): 2812) oxidize perfluoro-4-methyl-2-pentene to an epoxide using a sodium hypochlorite solution, but the reaction has poor positioning selectivity and Two epoxides are formed. Among them, an epoxide needs to be rearranged to perfluoroethyl isopropyl ketone under the catalysis of cesium fluoride; the other epoxide has higher activity and can be rearranged under the action of KF or triethylamine. As the target product, the yield is about 93%, and the reaction conditions are mild. The reaction is characterized by high yield of the hexafluoropropylene dimer which is easily obtained, but the reaction activity is different due to different epoxide catalytic rearrangement, and it needs to be oxidized, separated, separately rearranged and refined. In order to get the target product, the process is too complicated.

In view of the above phenomenon, the patent CN 102992986 B discloses a process for preparing perfluoroethyl isopropyl ketone. The specific process is a hexafluoropropylene dimer mixture, perfluoro-4-methyl-2-pentene or perfluoro-2-methyl-2-pentene as a raw material, olefin epoxidation, epoxide structure The reaction process such as rearrangement prepares perfluoroethyl isopropyl ketone. The aprotic polar solvent, catalyst and phase transfer catalyst are used in the preparation process to achieve high selectivity and high conversion rate of each step reaction. After simple separation of the reaction mixture, high quality intermediates and perfluoroethane can be obtained. Isopropyl ketone product. At the same time, a "one-pot" technique for double bond isomerization and epoxidation was established. The preparation technology provided by the invention has the characteristics of easy availability of raw materials, low cost, mild reaction conditions, safe and simple operation, high reaction selectivity and high conversion rate, small environmental impact, and the like, and is suitable for industrial application; however, the preparation method of the invention has certain Disadvantages: it is prepared by peroxidation and isomerization of perfluoro-4-methyl-2-pentene or perfluoro-2-methyl-2-pentene. Ketone technology, inevitably requires the use of a large amount of toxic solvents such as acetonitrile and a highly corrosive and irritating oxidizing agent sodium hypochlorite solution, resulting in a large amount of sewage and toxic solvents after reprocessing, and there are serious post-treatment and serious environmental pollution. point.

Summary of the invention

The technical problem to be solved by the present invention is to provide a preparation method of perfluoroethyl isopropyl ketone to solve the above technical problems.

In order to solve the above technical problem, the technical solution of the present invention is: a method for preparing perfluoroethyl isopropyl ketone, which is innovative in that the preparation method comprises the following steps: using perfluoro-4-methyl-2 a mixture of pentene or perfluoro-4-methyl-2-pentene and perfluoro-2-methyl-2-pentene, starting with perfluoro-4-methyl-2-pentene via an olefin The isomerization reaction is converted to perfluoro-2-methyl-2-pentene, and then perfluoro-2-methyl-2-pentene is epoxidized to perfluoro-2-methyl-2,3-cyclo Oxypentane, finally catalyzed rearrangement of perfluoro-2-methyl-2,3-epoxypentane to perfluoroethyl isopropyl ketone; including the following steps:

(1) Isomerization of perfluoro-4-methyl-2-pentene

Using perfluoro-4-methyl-2-pentene or a mixture of perfluoro-4-methyl-2-pentene and perfluoro-2-methyl-2-pentene as a raw material, perfluoro-4- Methyl-2-pentene is subjected to catalytic isomerization reaction in a solventless or aprotic polar solvent at 20 to 150 ° C for 4 to 30 hours, and the reaction is converted into perfluoro-2-methyl-2-pentene; Wherein, the catalytic isomerization reaction is synergistically catalyzed by a main catalyst, a cocatalyst and a catalyst promoter, and the mass ratio of the main catalyst, the cocatalyst, the catalyst promoter and the aprotic polar solvent is 1:0.1-5:0.5-5: 10～50; the molar ratio of the main catalyst to the raw material is 0.01-0.2; the main catalyst is tetra(N,N-dialkylamino)ethylene, cyanide salt, cyanate salt, thiocyanate, alkali. a metal fluoride, an alkaline earth metal fluoride, an aluminum fluorochloride, a Lewis acid or a mixture thereof, wherein the cocatalyst is an organic base selected from the group consisting of a crown ether, a polyethylene glycol, a quaternary ammonium salt or a mixture thereof. ;

(2) Epoxidation of perfluoro-2-methyl-2-pentene

The molar ratio of the oxidizing agent to perfluoro-2-methyl-2-pentene is 1 to 5; the volume ratio of the solvent to perfluoro-2-methyl-2-pentene is 0.2 to 5; at -20 to 60 ° C , the reaction is 0.1 to 8 h, and the perfluoro-2-methyl-2-pentene is quantitatively converted into perfluoro-2-methyl-2,3-epoxypentane; wherein the oxidizing agent is a tertiary amine oxynitride , N,N-dialkylhydroxylamine or a mixture thereof, the solvent being an aprotic polar solvent;

(3) Rearrangement reaction of perfluoro-2-methyl-2,3-epoxypentane

The volume ratio of the solvent to perfluoro-2-methyl-2,3-epoxypentane is 0.1-10, and the molar ratio of the catalyst to perfluoro-2-methyl-2,3-epoxypentane is 0.01~. 0.2, the molar ratio of the catalyst to the phase transfer catalyst is 0.05 to 0.15, the reaction temperature is 10 to 250 ° C, and the reaction time is 0.5 to 12 h, and the perfluoro-2-methyl-2,3-epoxypentane is converted into the whole Fluoroethyl isopropyl ketone; wherein the solvent is an aprotic polar solvent, the catalyst is an organic base or a Lewis acid, and the phase transfer catalyst is a crown ether, a polyethylene glycol, a quaternary ammonium salt or a season Barium salts or mixtures thereof.

The method for preparing perfluoroethyl isopropyl ketone according to the present invention, wherein the reaction temperature in the step (1) is from 20 to 150 ° C, but the preferred temperature is from 50 to 100 ° C; the reaction can be carried out under normal pressure, or in the system. It is carried out under pressure or under suitable pressure, but preferably at 0.2 to 1.0 MPa; step (1) can be carried out in an aprotic polar solvent, but it is preferred to use no solvent, but it is necessary to slightly increase the reaction. Temperature and pressure.

Further, in the epoxidation reaction of the step (2), a phase transfer catalyst may be further added, the molar ratio of the phase transfer catalyst to perfluoro-2-methyl-2-pentene is 0.01 to 0.5, and phase transfer The catalyst is a crown ether, polyethylene glycol, quaternary phosphonium salt or a mixture thereof.

Further, the tetrakis(N,N-dialkylamino)ethylene in the step (1) is tetrakis(N,N-dimethylamino)ethene or tetrakis(N,N-diethylamino)ethene, cyanide salt It is potassium cyanide, the cyanate is potassium cyanate, the thiocyanate is potassium thiocyanate, the alkali metal fluoride is cesium fluoride, and the alkaline earth metal fluoride is magnesium fluoride; thiocyanate is preferred. Potassium or tetrakis(diethylamino)ethylene is the catalyst of this step, especially the use of tetrakis(diethylamino)ethylene can be carried out in the absence of solvent, so that the conversion of the raw material can reach 99%.

Further, the tertiary amine nitrogen oxide in the step (2) is an aliphatic linear or branched tertiary amine nitrogen oxide, a morpholine nitrogen oxide, a pyridyl nitrogen oxide, a piperidine nitrogen oxide, an aniline nitrogen. As the oxide, benzylamine oxynitride or a mixture thereof, an aliphatic linear alkyl tertiary amine oxynitride such as (CH ₃ CH ₂ ) ₃ NO; N, N-di in the step (2) is preferably used. The alkyl group in the alkylhydroxylamine is a C1-C4 linear alkane, preferably (CH ₃ CH ₂ CH ₂ ) ₂ NOH.

Further, the organic base is trimethylamine, triethylamine, tributylamine, piperidine, N-methylpyridine, N,N-dimethylaniline, N,N-dimethylbenzylamine, N-A Hexacyclohexane, N-methylmorpholine, N-benzylmorpholine or a mixture thereof; preferably triethylamine or N,N-dimethylbenzylamine.

Further, the crown ether is 18-crown-6, 15-crown-5, dibenzo-18-crown-6 or a mixture thereof, and the polyethylene glycol is polyethylene glycol 400, polyethylene glycol 600 , polyethylene glycol 800, polyethylene glycol 1000, polyethylene glycol 4000, polyethylene glycol 6000 or a mixture thereof; preferably 18-crown-6 or polyethylene glycol 4000.

Further, the aprotic polar solvent is acetonitrile, N,N-dimethylacetamide, sulfolane, dimethyl sulfoxide, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol Two Methyl ether or a mixture thereof; preferably ethylene glycol dimethyl ether.

Further, the quaternary ammonium salt is dodecyldimethylbenzylammonium chloride, cetyltrimethylammonium bromide, cetyltrimethylammonium hydroxide, trioctylmethyl chloride Ammonium, tetrabutylammonium halide, tetrabutylammonium hydrogen sulfate or a mixture thereof; tetrabutylammonium hydrogen sulfate is preferred.

Further, the quaternary phosphonium salt is methyltriphenylphosphine chloride, tetrabutylphosphonium bromide or a mixture thereof.

Further, the Lewis acid is any one of antimony pentafluoride or aluminum chlorofluoride.

The advantages of the invention are:

(1) A method for producing perfluoroethyl isopropyl ketone according to the present invention, wherein the first step of catalytic isomerization can be carried out in the absence of a solvent to achieve high yield conversion of perfluoro-4-methyl-2-pentene to Perfluoro-2-methyl-2-pentene; the second step uses a tertiary amine oxynitride or N,N-dialkylhydroxylamine as an epoxidation reagent to achieve perfluoro-2-methyl-2-pentyl Quantitative conversion of olefins to perfluoro-2-methyl-2,3-epoxypentane avoids the problems of severe corrosion of equipment using sodium hypochlorite solution in the prior art, and the use of harsh conditions; the last step of catalytic rearrangement requires only catalyst The amount of organic amine or Lewis acid can make the yield of perfluoroethyl isopropyl ketone more than 95%;

(2) A method for producing perfluoroethyl isopropyl ketone according to the present invention, wherein, in the second step of the epoxy reaction, a phase transfer catalyst can be added, thereby further improving the efficiency of the reaction and saving time.

Detailed ways

The following examples are intended to provide a fuller understanding of the invention, and are not intended to limit the invention.

Example 1

1 g of potassium cyanide, 5 g of N-methylpyridine, 5 g of dibenzo-18-crown-6 and 50 g of acetonitrile were added to the flask, and 300 g of perfluoro-4-methyl-2-pentene was added to the reaction system. The reaction was stirred at 40 ° C for 20 h. After separation and purification, it was found that perfluoro-4-methyl-2-pentene B was converted to perfluoro-2-methyl-2-pentene, and the conversion of the reaction was 97.5%.

0.3 mol (CH ₃ CH ₂ CH ₂ ) ₂ NOH, 18.5 mL of N,N-dimethylacetamide and 0.05 mol of tetrabutylphosphonium bromide were added to a three-necked flask, and then 0.1 mol of the above perfluoro-2-methyl group was added. Base-2-pentene was stirred at 40 ° C for 2 h. After separation and purification, it was found that perfluoro-2-methyl-2-pentene was quantitatively converted to perfluoro-2-methyl-2,3-epoxypentane.

30 mL of ethylene glycol dimethyl ether, 0.2 mol of N,N-dimethylbenzylamine and 0.1 mol of methyltriphenylphosphonium chloride were added to the flask, and then 1 mol of perfluoro-2-methyl-2 prepared above was added. 3-epoxypentane was continuously stirred at 20 ° C for 2 h. After separation and purification, it was found that perfluoro-2-methyl-2,3-epoxypentane had been quantitatively converted to perfluoroethyl isopropyl ketone.

Example 2

2 g of potassium thiocyanate, 0.7 g of N,N-dimethylbenzylamine, 2 g of polyethylene glycol 4000 and 30 g of diethylene glycol dimethyl ether were added to the flask, and 300 g of perfluoro-4-methyl-2 was further added. -pentene was added to the reaction system, and the reaction was stirred at 90 ° C, 0.3 MPa for 6 h. After separation and purification, it was found that perfluoro-4-methyl-2-pentene B was converted to perfluoro-2-methyl-2-pentene, and the conversion ratio of the reaction was 99.7%.

0.1 mol (CH ₃ CH ₂ ) ₂ NOH, 15 mL of N,N-dimethylacetamide was added to a three-necked flask, and then 0.1 mol of perfluoro-2-methyl-2-pentene was added thereto, and it was continued at 70 ° C. The reaction was stirred for 8 h. After separation and purification, it was found that perfluoro-2-methyl-2-pentene was converted to perfluoro-2-methyl-2,3-epoxypentane, and the conversion of the reaction was 98.9%.

40 mL of ethylene glycol dimethyl ether, 0.06 mol of triethylamine and 0.05 mol of 18-crown-6 were added to the flask, followed by the addition of 1 mol of perfluoro-2-methyl-2,3-epoxypentane prepared above, at 20 The reaction was continuously stirred at ° C for 5 h. After separation and purification, it was found that perfluoro-2-methyl-2,3-epoxypentane had been quantitatively converted to perfluoroethyl isopropyl ketone.

Example 3

1 g of antimony pentafluoride, 3 g of N-methylpyridine and 1 g of 18-crown-6 were added to the flask, and 300 g of perfluoro-4-methyl-2-pentene was added to the reaction system, and the reaction was stirred at 120 ° C. 25h. After separation and purification, it was found that perfluoro-4-methyl-2-pentene B was converted to perfluoro-2-methyl-2-pentene, and the conversion of the reaction was 98.1%.

0.3 mol of (CH ₃ ) ₂ NOH, 40 mL of N,N-dimethylacetamide and 0.03 mol of tetrabutylphosphonium bromide were added to a three-necked flask, and then 0.1 mol of the above perfluoro-2-methyl-2- was added. The pentene was continuously stirred at 20 ° C for 8 h. After separation and purification, it was found that perfluoro-2-methyl-2-pentene was converted to perfluoro-2-methyl-2,3-epoxypentane.

8 mL of tetraethylene glycol dimethyl ether, 0.1 mol of tributylamine and 0.08 mol of polyethylene glycol 4000 were added to the flask, and then 1 mol of perfluoro-2-methyl-2,3-epoxypentane prepared above was added. Stirring was continued for 8 h at 30 °C. After separation and purification, it was found that perfluoro-2-methyl-2,3-epoxypentane had been quantitatively converted to perfluoroethyl isopropyl ketone.

Example 4

10 g of tetrakis(N,N-dimethylamino)ethylene, 1 g of trimethylamine, 5 g of polyethylene glycol 4000 and 100 g of sulfolane were added to the flask, and 300 g of perfluoro-4-methyl-2-pentene was added to the reaction. In the system, the reaction was stirred at 40 ° C for 5 h. After separation and purification, the analysis found that The conversion of fluoro-4-methyl-2-pentene B to perfluoro-2-methyl-2-pentene gave a conversion of 99.6%.

0.1 mol of (CH ₃ CH ₂ ) ₃ NO, 8 mL of ethylene glycol dimethyl ether and 0.01 mol of polyethylene glycol 600 were placed in a three-necked flask, and then 0.1 mol of perfluoro-2-methyl-2-pentene was added thereto. The reaction was continuously stirred at 50 ° C for 5 h. After separation and purification, it was found that perfluoro-2-methyl-2-pentene had been converted to perfluoro-2-methyl-2,3-epoxypentane, and the conversion of the reaction was 98.9%.

50 mL of sulfolane, 0.06 mol of N-benzylmorpholine and 0.05 mol of methyltriphenylphosphonium chloride were added to the flask, and then 1 mol of perfluoro-2-methyl-2,3-epoxypentane prepared above was added. The reaction was continuously stirred at 60 ° C for 8 h. After separation and purification, it was found that perfluoro-2-methyl-2,3-epoxypentane had been quantitatively converted to perfluoroethyl isopropyl ketone.

Example 5

1 g of a mixture of magnesium fluoride and aluminum fluoride, 0.2 g of N-benzylmorpholine, 0.7 g of polyethylene glycol 1000 and 20 g of ethylene glycol dimethyl ether were added to the flask, and then 300 g of perfluoro-4-methyl-2 was added. The pentene was added to the reaction system, and the reaction was stirred at 60 ° C for 24 hours. After separation and purification, it was found that perfluoro-4-methyl-2-pentene B was converted to perfluoro-2-methyl-2-pentene, and the conversion of the reaction was 98.5%.

0.1 mol (CH ₃ CH ₂ CH ₂ ) ₃ NO, 18 mL of diethylene glycol dimethyl ether and 0.01 mol of 18-crown-6 were added to a three-necked flask, and then 0.1 mol of perfluoro-2-methyl-2-pentane was added thereto. The ene was continuously stirred at 0 ° C for 8 h. After separation and purification, it was found that perfluoro-2-methyl-2-pentene had been converted to perfluoro-2-methyl-2,3-epoxypentane, and the conversion of the reaction was 98.9%.

80 mL of dimethyl sulfoxide, 0.06 mol of N-methylcyclohexylamine, and 0.05 mol of 15-crown-5 The flask was placed in a flask, and then 1 mol of perfluoro-2-methyl-2,3-epoxypentane prepared above was added, and the reaction was continuously stirred at 70 ° C for 12 hours. After separation and purification, it was found that perfluoro-2-methyl-2,3-epoxypentane had been quantitatively converted to perfluoroethyl isopropyl ketone.

Example 6

10 g of cesium fluoride, 2 g of N, dimethylaniline and 5 g of 15-crown-5 were added to the flask, and then 300 g of perfluoro-4-methyl-2-pentene was added to the reaction system and stirred at 50 ° C. Reaction 29h. After separation and purification, it was found that perfluoro-4-methyl-2-pentene B was converted to perfluoro-2-methyl-2-pentene, and the conversion of the reaction was 99.8%.

0.1 mol (CH ₃ CH ₂ CH ₂ CH ₂ ) ₃ NO, 13 mL of tetraethylene glycol dimethyl ether and 0.01 mol of methyltriphenylphosphine chloride were added to a three-necked flask, and then 0.1 mol of perfluoro-2-benzene was added thereto. Methyl-2-pentene was continuously stirred at -5 °C for 3 h. After separation and purification, it was found that perfluoro-2-methyl-2-pentene had been converted to perfluoro-2-methyl-2,3-epoxypentane, and the conversion of the reaction was 98.9%.

60 mL of acetonitrile, 0.06 mol of antimony pentafluoride and 0.05 mol of methyltriphenylphosphonium chloride were added to the flask, and then 1 mol of perfluoro-2-methyl-2,3-epoxypentane prepared above was added at 110. The reaction was stirred at ° C for 12 h. After separation and purification, it was found that perfluoro-2-methyl-2,3-epoxypentane had been quantitatively converted to perfluoroethyl isopropyl ketone.

The basic principles and main features of the invention and the advantages of the invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited by the foregoing embodiments, and that the present invention is only described in the foregoing description and the description of the present invention, without departing from the spirit and scope of the invention. Various changes and modifications are intended to be included within the scope of the invention as claimed. The claimed scope of the invention is attached The claims and their equivalents are defined.

Claims

A method for preparing perfluoroethyl isopropyl ketone, characterized in that the preparation method comprises the steps of: perfluoro-4-methyl-2-pentene or perfluoro-4-methyl-2- A mixture of pentene and perfluoro-2-methyl-2-pentene is used as a raw material, and perfluoro-4-methyl-2-pentene is first converted to perfluoro-2-methyl by olefin isomerization reaction. 2-pentene, epoxidized perfluoro-2-methyl-2-pentene to perfluoro-2-methyl-2,3-epoxypentane, and finally perfluoro-2-methyl- Catalytic rearrangement of 2,3-epoxypentane to perfluoroethyl isopropyl ketone; including the following steps:

(1) Isomerization of perfluoro-4-methyl-2-pentene

Using perfluoro-4-methyl-2-pentene or a mixture of perfluoro-4-methyl-2-pentene and perfluoro-2-methyl-2-pentene as a raw material, perfluoro-4- Methyl-2-pentene is subjected to catalytic isomerization reaction in a solventless or aprotic polar solvent at 20 to 150 ° C for 4 to 30 hours, and converted into perfluoro-2-methyl-2-pentene; The catalytic isomerization reaction is synergistically catalyzed by a main catalyst, a cocatalyst and a catalyst promoter, and the mass ratio of the main catalyst, the cocatalyst, the catalyst promoter and the aprotic polar solvent is 1:0.1-5:0.5-5: 10～50; the molar ratio of the main catalyst to the raw material is 0.01-0.2; the main catalyst is tetra(N,N-dialkylamino)ethylene, cyanide salt, cyanate salt, thiocyanate, alkali. a metal fluoride, an alkaline earth metal fluoride, a Lewis acid or a mixture thereof, the cocatalyst is an organic base selected from the group consisting of a crown ether, a polyethylene glycol, a quaternary ammonium salt or a mixture thereof;

(2) Epoxidation of perfluoro-2-methyl-2-pentene

The molar ratio of the oxidizing agent to perfluoro-2-methyl-2-pentene is 1 to 5; the volume ratio of the solvent to perfluoro-2-methyl-2-pentene is 0.2 to 5; at -20 to 60 ° C , the reaction is 0.1 to 8 h, and the perfluoro-2-methyl-2-pentene is quantitatively converted into perfluoro-2-methyl-2,3-epoxypentane; wherein the oxidizing agent is a tertiary amine oxynitride , N,N-dialkylhydroxylamine or a mixture thereof, the solvent being an aprotic polar solvent;

(3) Rearrangement reaction of perfluoro-2-methyl-2,3-epoxypentane

The volume ratio of the solvent to perfluoro-2-methyl-2,3-epoxypentane is 0.1-10, and the molar ratio of the catalyst to perfluoro-2-methyl-2,3-epoxypentane is 0.01~. 0.2, the molar ratio of the catalyst to the phase transfer catalyst is 0.05 to 0.15, the reaction temperature is 10 to 250 ° C, and the reaction time is 0.5 to 12 h, and the perfluoro-2-methyl-2,3-epoxypentane is converted into the whole Fluoroethyl isopropyl ketone; wherein the solvent is an aprotic polar solvent, the catalyst is an organic base or a Lewis acid, and the phase transfer catalyst is a crown ether, a polyethylene glycol, a quaternary ammonium salt or a season Barium salts or mixtures thereof.
The method for producing perfluoroethyl isopropyl ketone according to claim 1, characterized in that, in the epoxidation reaction of the step (2), a phase transfer catalyst, the phase transfer catalyst and perfluoro- The molar ratio of 2-methyl-2-pentene is from 0.01 to 0.5, and the phase transfer catalyst is a crown ether, polyethylene glycol, quaternary phosphonium salt or a mixture thereof.
The method for preparing perfluoroethyl isopropyl ketone according to claim 1, wherein the tetrakis(N,N-dialkylamino)ethylene in the step (1) is tetrakis (N,N-di Methylamino)ethylene or tetrakis(N,N-diethylamino)ethylene, the cyanide salt is potassium cyanide, the cyanate is potassium cyanate, the thiocyanate is potassium thiocyanate, and the alkali metal fluoride is Barium fluoride, alkaline earth metal The fluoride is magnesium fluoride.
The method for preparing perfluoroethyl isopropyl ketone according to claim 1, wherein the tertiary amine oxynitride in the step (2) is an aliphatic linear or branched tertiary amine oxynitride. , morpholine oxynitride, pyridine oxynitride, piperidine oxynitride, aniline oxynitride, benzylamine oxynitride or a mixture thereof, the alkane in the N,N-dialkylhydroxylamine in step (2) The base is selected from C1 to C4 linear alkane.
The method for preparing perfluoroethyl isopropyl ketone according to claim 1, wherein the organic base is trimethylamine, triethylamine, tributylamine, piperidine, N-methylpyridine, N, N-dimethylaniline, N,N-dimethylbenzylamine, N-methylcyclohexanediamine, N-methylmorpholine, N-benzylmorpholine or a mixture thereof.
The method for producing perfluoroethyl isopropyl ketone according to claim 1 or 2, wherein the crown ether is 18-crown-6, 15-crown-5, dibenzo-18-crown- 6 or a mixture thereof, polyethylene glycol is polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 1000, polyethylene glycol 4000, polyethylene glycol 6000 or a mixture thereof .
The method for preparing perfluoroethyl isopropyl ketone according to claim 1, wherein the aprotic polar solvent is acetonitrile, N,N-dimethylacetamide, sulfolane, dimethyl sulfoxide. , ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether or a mixture thereof.
The method for producing perfluoroethyl isopropyl ketone according to claim 1, wherein the quaternary ammonium salt is dodecyldimethylbenzylammonium chloride or cetyltrimethyl bromide. Ammonium, cetyltrimethylammonium hydroxide, trioctylmethylammonium chloride, tetrabutylammonium halide, tetrabutylammonium hydrogen sulfate or a mixture thereof.
The method for producing perfluoroethyl isopropyl ketone according to claim 1 or 2, wherein the quaternary phosphonium salt is methyltriphenylphosphine chloride, tetrabutylphosphonium bromide or a mixture thereof .
The method for producing perfluoroethyl isopropyl ketone according to claim 1, wherein the Lewis acid is any one of antimony pentafluoride or aluminum chlorofluoride.