Search

CN-121990864-A - Hexafluoroisopropyl preparation method of butene

CN121990864ACN 121990864 ACN121990864 ACN 121990864ACN-121990864-A

Abstract

The invention belongs to the technical field of hexafluoroisobutylene preparation, in particular to a preparation method of hexafluoroisobutylene, which comprises the steps of adding anhydrous tetrahydrofuran solvent into an autoclave under the condition of maintaining inert atmosphere in the whole process, then adding methyl triphenyl phosphorus bromide raw material, stabilizing the temperature in the autoclave at 0 ℃, adding organic base with preset equivalent weight into the autoclave, continuously stirring and reacting for 4 hours under the condition of 0 ℃ and inert atmosphere, obtaining tetrahydrofuran solution of methylene triphenyl phosphorus serving as a ylide reagent, reducing the temperature to-30 ℃, introducing anhydrous hexafluoroacetone into the autoclave, reacting for 10 h, slowly heating to 30 ℃ and continuously stirring and reacting for 10 h. The method has the advantages of simple reaction process, mild reaction conditions, harmless generated byproducts and convenient treatment, ensures the continuous operation of the reaction device, and has high purity and high yield of the prepared hexafluoroisobutylene product.

Inventors

  • NI ZHIQIANG
  • QIAN ZHIJUN
  • YANG YU

Assignees

  • 威斯特(东营)特种气体有限公司

Dates

Publication Date
20260508
Application Date
20260126

Claims (9)

  1. 1. A preparation method of hexafluoroisobutylene is characterized by comprising the following steps: S1, adding an anhydrous tetrahydrofuran solvent into an autoclave under the condition of maintaining an inert atmosphere in the whole process; s2, adding the methyl triphenyl phosphonium bromide raw material, stirring to completely dissolve the methyl triphenyl phosphonium bromide raw material, and stabilizing the temperature in the process control autoclave at 0 ℃; s3, after the raw materials are dissolved, adding organic base with preset equivalent weight into the raw materials, and continuously stirring the raw materials for reaction for 4 hours at 0 ℃ in an inert atmosphere to obtain a tetrahydrofuran solution of methylene triphenylphosphine serving as a ylide reagent; s4, gradually reducing the temperature in the autoclave to-30 ℃ and keeping the temperature at constant temperature, slowly introducing hexafluoroacetone gas into the autoclave through a gas conduit under the low temperature condition, controlling the ventilation rate to maintain the pressure of the system stable, avoiding the partial reaction to be too severe, sealing the autoclave after ventilation is finished, and continuously stirring the autoclave at the temperature of-30 ℃ for reaction for 10 hours; S5, after the low-temperature control is released, the temperature of the system is raised to 30 ℃, and the reaction is continuously stirred for 10 hours at the temperature, so that the sufficient addition reaction of hexafluoroacetone and methylene triphenyl phosphate is ensured, and finally the target reaction process is completed.
  2. 2. The method for preparing hexafluoroisobutylene according to claim 1, wherein the hexafluoroacetone in S4 is anhydrous hexafluoroacetone.
  3. 3. The method for preparing hexafluoroisobutylene according to claim 1, wherein the molar ratio/mass ratio of hexafluoroacetone to methylene triphenylphosphine in S3 and S4 is 1:1.5-2.5.
  4. 4. The method for producing hexafluoroisobutylene according to claim 1, wherein the stirring speed in the above step is 100 to 500r/min.
  5. 5. A process for preparing hexafluoroisobutylene as claimed in claim 1, wherein the anhydrous tetrahydrofuran solvent in S1 is replaced by diethyl ether or combined with diethyl ether.
  6. 6. The method for preparing hexafluoroisobutylene according to claim 1, wherein the organic base in S3 is any one or a combination of at least two of potassium tert-butoxide, sodium ethoxide and sodium methoxide.
  7. 7. The method for preparing hexafluoroisobutylene according to claim 5, wherein the anhydrous tetrahydrofuran solvent in S1 and S2 has a mass four times that of methyltriphenyl phosphorus bromide.
  8. 8. The method for preparing hexafluoroisobutylene according to claim 1, wherein the molar ratio of methyltriphenyl phosphorus bromide to organic base in S2 and S3 is 1:1.2-2.
  9. 9. A process for producing hexafluoroisobutylene according to claim 1, wherein the inert gas comprises any one or a combination of at least two of nitrogen, helium, neon or argon.

Description

Hexafluoroisopropyl preparation method of butene Technical Field The invention relates to the technical field of hexafluoroisobutylene preparation, in particular to a preparation method of hexafluoroisobutylene. Background Hexafluoroisobutylene (3, 3-trifluoro-2- (trifluoromethyl) -1-propene, HFIB) is a relatively useful chemical product and is also an important fluoromonomer for developing novel fluoropolymers. The application is very wide, and the material can be used for preparing piezoelectric materials, lubricating materials, special elastomers, fluorine coating materials, semiconductor photoetching materials, refrigerants, drug intermediates and the like. And new application fields are continuously being discovered. HFIB has attracted more and more attention, and its preparation process has been attracting more attention. Hexafluoroisobutylene is an important chemical product with wide application and great development potential. At present, the HFIB synthesis methods are mainly divided into 4 types according to different reaction types, namely an elimination method, an open-loop method, a fluorine-chlorine exchange method and a decarboxylation method. The following are some descriptions of the preparation process: 1. Elimination method The elimination method is to take (CF 3) 2CHCH2F, (CF 3) 2CHCH2OH, (CF 3) 2CFCH2F and other substances as raw materials, and obtain hexafluoroisobutylene and water, or HF, F2 and other substances after elimination. For example, patent CN107032950A, CN107151198a, etc. The route has high reaction activity, short steps and high yield, but the used raw materials are special and not easy to obtain, and the raw materials need to be low-cost sources for industrialization. 2. Open loop process The ring opening method is mainly a method for preparing hexafluoroisobutylene through reaction by preparing ring intermediates of oxygen, sulfur and phosphorus. Including hexafluoroacetone with ketene (patent CN107011116 a), hexafluoropropylene with sulfur powder (patent EP0068080B 1), phosphorus-containing alkylene oxide heating, and the like. The raw material used in the method can be hexafluoroacetone, hexafluoropropylene or phosphorus-containing alkylene oxide. However, either has the respective problems that hexafluoropropylene raw materials are cheap and easy to obtain, but the yield is low, so that the hexafluoropropylene raw materials are not suitable for industrial production. The hexafluoroacetone and ketene method has the advantages of short process route and high yield, but anhydrous hexafluoroacetone and ketene have strong toxicity, ketene is unstable, the reaction process has large difficulty, the yield is relatively low, the cost is high, and the industrialization is not facilitated. 3. Fluorine-chlorine exchange method The fluorine-chlorine exchange method is mainly prepared by 3-chlorine-3, 3-trifluoro-2- (trifluoromethyl) -1-propylene and the like through a fluorine-chlorine exchange substitution method by using chlorine to substitute raw materials of fluorine in hexafluoroisobutylene. The raw materials used by the method are not easy to obtain or the cost of the raw materials is too high, so the method is not suitable for industrialization. 4. Decarboxylation process The decarboxylation method is to react octafluoroisobutylene with alcohol to obtain (CF 3) 2CHCF2OR, (CF 3) 2CHCF2OR, which is then hydrolyzed to obtain (CF 3) 2CHCOOR, (CF 3) 2CHCOOR, and then chloridizing (OR formaldehyde condensing) and decarboxylating to obtain HFIB. For example patent JP1987252735A, DE3635750. The raw materials used by the method are not easy to obtain, the route is long, the conversion rate is low, and the method is not suitable for industrial production. The present we propose a preparation method of hexafluoroisobutylene to obtain the finished product with high purity and high yield. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides a preparation method of hexafluoroisobutylene, which solves the problems in the prior art. (II) technical scheme The invention adopts the following technical scheme for realizing the purposes: A method for preparing hexafluoroisobutylene, comprising the steps of: S1, adding an anhydrous tetrahydrofuran solvent into an autoclave under the condition of maintaining an inert atmosphere in the whole process; s2, adding the methyl triphenyl phosphonium bromide raw material, stirring to completely dissolve the methyl triphenyl phosphonium bromide raw material, and stabilizing the temperature in the process control autoclave at 0 ℃; s3, after the raw materials are dissolved, adding organic base with preset equivalent weight into the raw materials, and continuously stirring the raw materials for reaction for 4 hours at 0 ℃ in an inert atmosphere to obtain a tetrahydrofuran solution of methylene triphenylphosphine serving as a ylide reagent; s4, gradually reducing the temperature in the au