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CN-122010691-A - Method for preparing methyl trifluoromethyl ether

CN122010691ACN 122010691 ACN122010691 ACN 122010691ACN-122010691-A

Abstract

The invention relates to the technical field of fluorine chemical engineering, in particular to a method for preparing methyl trifluoromethyl ether, which comprises the following steps: and reacting the trifluoromethyl chloroformate with a methylating agent in the presence of a fluorine salt to obtain methyl trifluoromethyl ether. According to the invention, the trifluoromethyl chloroformate is used for replacing carbonyl fluoride, so that the use of the highly toxic raw material carbonyl fluoride is avoided, and the requirement on equipment is reduced. The reaction condition is mild, the process is simple, and the product is easy to separate.

Inventors

  • WANG JIANXIN
  • ZHOU YUJI
  • ZHOU JICANG
  • CHEN RUICAO
  • YU QIANG
  • GAN ZHIXING
  • YU DINGHUI

Assignees

  • 漳平市九鼎泰天科技有限公司
  • 福建省漳平市九鼎氟化工有限公司

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. A process for preparing methyl trifluoromethyl ether comprising the steps of: And reacting the trifluoromethyl chloroformate with a methylating agent in the presence of a fluorine salt to obtain methyl trifluoromethyl ether.
  2. 2. The process for preparing methyltrifluoromethyl ether according to claim 1, wherein the fluoride salt is an alkali metal fluoride and/or tetramethyl ammonium fluoride.
  3. 3. The method for preparing methyl trifluoromethyl ether according to claim 2, wherein the fluorine salt comprises one or more of sodium fluoride, potassium fluoride, cesium fluoride and tetramethyl ammonium fluoride.
  4. 4. The method for preparing methyl trifluoromethyl ether according to claim 1, wherein the methylating agent is selected from dimethyl sulfate, methyl iodide, methyl bromide, methyl chloride, methyl p-toluenesulfonate and methyl chloroformate.
  5. 5. The method for preparing methyl trifluoromethyl ether according to claim 1, wherein the reaction temperature is 0-200 ℃, the reaction time is 1-100 h, and the reaction pressure is 0-100 kg.
  6. 6. The method for preparing methyl trifluoromethyl ether according to claim 1, wherein the solvent for the reaction comprises one or more of diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, N-dimethylformamide, dimethyl sulfoxide, and acetonitrile.
  7. 7. The method for preparing methyl trifluoromethyl ether according to claim 1, wherein a phase transfer catalyst is added to the reaction system.
  8. 8. The method for preparing methyl trifluoromethyl ether according to claim 7, wherein the phase transfer catalyst comprises one or more of polyether, quaternary ammonium salt and crown ether.
  9. 9. The process for preparing methyltrifluoromethyl ether according to claim 8, wherein said polyether is selected from polyethylene glycol dialkyl ethers; the quaternary ammonium salt is selected from one or more of benzyl triethyl ammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bisulfate, trioctylmethyl ammonium chloride, dodecyl trimethyl ammonium chloride, tetradecyl trimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride; the crown ether is selected from one or more of 15-crown 5, 18-crown-6.
  10. 10. The method for preparing methyl trifluoromethyl ether according to any one of claims 1 to 9, characterized in that the molar ratio of the trifluoromethyl chloroformate to the fluorine salt is 1 (2 to 20); the molar ratio of the trifluoromethyl chloroformate to the methylation reagent is 1 (2-20); the molar ratio of the trifluoromethyl chloroformate to the phase transfer catalyst is 1 (0-1).

Description

Method for preparing methyl trifluoromethyl ether Technical Field The invention relates to the technical field of fluorine chemical industry, in particular to a method for preparing methyl trifluoromethyl ether. Background The hydrofluoroether CF 3OCH3 (methyl trifluoromethyl ether, also called HFE-143a, HFE-143m, etc.) is a novel refrigerant which can replace CFCs, HCFCs and HFCs, and the GWP100 is only 680, which is far lower than the common refrigerants CFC-12 and HFC-134a. Researches show that the heat transfer coefficient of HFE-143m boiling and condensing and the heat transfer coefficient of HFC-134a are very close, the running pressure of HFE143m is lower than that of HFC134a, the refrigerating capacity and COP of unit mass are respectively improved by 2.9% and 3.6% under the isentropic compression working condition, and the refrigerating capacity and COP of unit mass are respectively improved by 2.9% and 16.6% under the working condition of fixed compressor outlet superheat (25 ℃), so that the HFE-143m is a potential substitute of HFC134 a. In recent years, as there has been an increasing concern that the continuous emission of short carbon chain PFAS, especially trifluoroacetic acid (TFA), constitutes a high potential risk to environmental ecology and human health, next generation products have been developed to replace HFO-1234yf, which is now widely used (such substances raise concerns due to its decomposition product in the atmosphere being TFA). As HFE-143m can not generate trifluoroacetic acid after being degraded in the atmosphere, the HFE-143m has a great application prospect as a potential substitute for HFO-1234 yf. There are many reports on the synthesis of HFE-143 m. Mainly comprises direct fluorination of ether compounds, electrochemical fluorination of ether compounds, alkylation of fluorine-containing alcohols and alkylation of acyl fluorides. The direct fluorination method can use high-valence metal fluorides (such as SbF 5、CoF3、MnF3, etc.) for fluorination, but the price of the fluorinating agent is high, and the method is not suitable for industrial production, or F 2, halogen fluoride, etc., but the selectivity of the fluorinating agent is poor. The electrolytic fluorination method can be used for preparing a plurality of organic fluorides with functional groups, but the yield of the perfluoroalkyl ether prepared by the electrolytic fluorination is lower, and the discharge of three wastes is serious, so that the environmental impact is larger. In early synthesis, the elimination reaction between fluorine-containing alcohol (or phenol) and haloalkane molecules is carried out to prepare hydrofluoroether, and Rf 1X+Rf2 OH is reacted to obtain Rf 1ORf2 +MX (wherein Rf is fluorine-containing alkyl, X is I, br and Cl), but the method needs to be carried out at high temperature and high pressure, and the yield of the hydrofluoroether is low and is eliminated. How to realize the industrial production of methyl trifluoromethyl ether is a technical problem which needs to be solved at present. Disclosure of Invention In view of the above, the technical problem to be solved by the invention is to provide a method for preparing methyl trifluoromethyl ether, which is suitable for industrial production. To achieve the above object, the present invention provides a method for preparing methyl trifluoromethyl ether, comprising the steps of: And reacting the trifluoromethyl chloroformate with a methylating agent in the presence of a fluorine salt to obtain methyl trifluoromethyl ether. The fluoride salt is preferably an alkali metal fluoride and/or tetramethyl ammonium fluoride, and in some embodiments, the fluoride salt comprises one or more of sodium fluoride, potassium fluoride, cesium fluoride, tetramethyl ammonium fluoride. Most preferred is potassium fluoride or cesium fluoride. The methylating agent is preferably selected from dimethyl sulphate, methyl iodide, methyl bromide, methyl chloride, methyl p-toluene sulphonate or methyl chloroformate. The temperature of the reaction is preferably 0 to 200 ℃, more preferably 25 to 160 ℃, still more preferably 30 to 150 ℃, and may be 30, 45, 60 or 150 ℃ by way of example. The reaction time is preferably 1 to 100 hours, more preferably 4 to 48 hours, still more preferably 18 to 36 hours, and may be 18, 24 or 36 hours, for example. The pressure of the reaction is preferably 0to 100 kg, more preferably 0to 20 kg, and may be, for example, 0,10 or 20 kg. The solvent for the reaction preferably comprises one or more of diethylene glycol dimethyl ether (DG), tetraethylene glycol dimethyl ether, N-Dimethylformamide (DMF), dimethyl sulfoxide and acetonitrile. In the present invention, when the methylating agent is dimethyl sulfate, the solvent may be selected from among those which are not used. In order to further increase the reaction yield, a phase transfer catalyst is preferably added to the reaction system. Preferably, the phase transfer catalyst compris