JPS6121537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing the compound 1,1,2-trifluoro-2-chloroethyl difluoromethyl ether, which is useful as a general inhalation anesthetic. Generally, in the fluorination reaction of chloroethers having a chlorine atom adjacent to a coordination atom, the purpose can be easily achieved by using antimony trifluoride as a fluorination agent. However, in order to produce the above-mentioned 1,1,2-trifluoro-2-chloroethyl difluoromethyl ether, when antimony trifluoride is allowed to act on 1,1,2-trifluoro-2-chloroethyl dichloromethyl ether. However, the activity of antimony trifluoride is low and the purpose of fluorination cannot be easily achieved. Antimony trifluoride has low activity when used alone, but when pentavalent antimony halides or stannic halides are present, its activity is increased and the purpose of fluorination can be easily achieved. (Specification of Japanese Patent Publication No. 48-3606) The present inventors investigated the possibility of using other catalysts in the above-mentioned fluorine reaction with the aim of further developing this method, but most of them were not found to be practical. For example, chromium trifluoride, aluminum fluoride, cupric bromide, ferric chloride, thallium chloride, etc. are catalysts often used in fluorination reactions;
In the above reaction of fluorinating 2-trifluoro-2-chloroethyl dichloromethyl ether with antimony trifluoride, substantially no catalytic action can be observed. Titanium tetrachloride, thallium oxide, etc., which are also often used in fluorination reactions, cause decomposition of the raw material, so 1,1,
Although 2-trifluoro-2-chloroethyl difluoromethyl ether is obtained, the yield is extremely poor. Thus, the selection and use of a specific catalyst in the fluorination reaction has important industrial significance. As mentioned above, the present invention was completed based on the discovery of a practical catalyst for a specific fluorination method in which selection of an appropriate catalyst is extremely difficult. , 1, 1, 2-
1, characterized in that trifluoro-2-chloroethyl dichloromethyl ether is fluorinated using antimony trifluoride in the presence of a pentavalent molybdenum compound or a hexavalent tungsten compound;
It consists in a method for producing 1,2-trifluoro-2-chloroethyl difluoromethyl ether. To carry out the method of the invention, usually 1, 1, 2
-trifluoro-2-chloroethyl dichloromethyl ether in the presence of about 5 to 50% by weight of a pentavalent molybdenum compound or a hexavalent tungsten compound,
Fluorination may be carried out using about 0.7 mol to about 2 molar equivalents of antimony trifluoride at a temperature of about 0°C to about 100°C. As the pentavalent molybdenum compound used in the method of the present invention, for example, molybdenum pentafluoride or molybdenum pentachloride is used. Preferably, inexpensive molybdenum pentachloride is used. Further, as the hexavalent tungsten compound, for example, tungsten hexafluoride or tungsten hexachloride is used, and tungsten hexachloride is preferably used. The amount of catalyst used is about 5 to 50% by weight, preferably about 10% by weight, based on the raw material 1,1,2-trifluoro-2-chloroethyl dichloromethyl ether. Antimony trifluoride is used as the fluorinating agent in the method of the present invention. The amount of antimony trifluoride used is usually about 0.7 to 2 molar equivalents, preferably 1.8 molar equivalents, based on the raw material 1,1,2-trifluoro-2-chloroethyldichloromethyldichloromethyl ether. Solvents are not normally used in carrying out the process of the invention. The reaction is carried out at a temperature of about 0-100°C, preferably between the boiling point of the product (56.5°C) and 70°C. Under such conditions, the reaction product is distilled from the reaction mixture as it is produced, and undesirable side reactions can be prevented from proceeding. Note that unreacted substances and monofluorinated reactants are recovered and reused. Next, examples will be shown to specifically explain the present invention. The percentage below indicates weight. Example 1 20 g of antimony trifluoride in a glass flask
and 1.5 g of molybdenum pentachloride at 60-70℃.
Stir while heating.
15.0 g of CHCl ₂ OCF ₂ CFClH (purity 91.8%) was gradually added dropwise. The product was distilled simultaneously with production to obtain 11.1 g of distillate. When this was analyzed using a gas chromatograph, the target product CHF ₂ OCF ₂ CFClH80.4
%, monofluoride CHClFOCF ₂ CFClH9.2%,
It contained 0.6% of unreacted CHCl ₂ OCF ₂ CFClH and others. Example 2 Antimony trifluoride in a glass flask at room temperature
20g, molybdenum pentachloride 1.5g,
15.0 g of CHCl ₂ OCF ₂ CFClH (purity 91.8%) was charged and stirred at room temperature for 10 minutes. Heat the flask to 65℃
Distillation was carried out by placing the product in an oil bath heated to a temperature of
CHF ₂ OCF ₂ CFClH91.4%, monofluoride
CHClFOCF ₂ CFClH0.3%, unreacted material
Contained CHCl ₂ OCF ₂ CFClH0.4% and others. Examples 3 to 5 Reactions were carried out according to Example 1 using the types and amounts of catalysts shown in Table 1, and the results shown in Table 1 were obtained. 【table】

Claims (1)

[Claims] 1 1,1,1,2-trifluoro-2-chloroethyl dichloromethyl ether is treated with fluorine using antimony trifluoride in the presence of a pentavalent molybdenum compound or a hexavalent tungsten compound. 1,1,2-trifluoro-2-
Method for producing chloroethyl difluoromethyl ether. 2. The production method according to claim 1, wherein the pentavalent molybdenum compound is molybdenum pentachloride or molybdenum pentafluoride. 3. The manufacturing method according to claim 1, wherein the hexavalent tungsten compound is tungsten hexachloride or tungsten hexafluoride. 4. The production method according to claim 1, wherein the fluorination is carried out at a reaction temperature of 0 to 100°C.