Method for preparing trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether

Abstract

The invention discloses a method for preparing trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether, which comprises the following steps of: 1) continuously introducing gaseous fluoroxy trifluoromethane thinned by using nitrogen from the lower part of a reaction tower, wherein the content of the fluoroxy trifluoromethane is 5 to 50 volume percent; 2) introducing quantitative liquid 1,2-difluoro-1,2-dichloroethylene from the upper part of the reaction tower to countercurrent contact and react with the gaseous fluoroxy trifluoromethane, controlling the reaction temperature to be between 110 DEG C below zero and 5 DEG C below zero through a heat exchange device, generating the trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether, and discharging the un-reacted incoagulable gas from the top of the reaction tower for neutralization treatment; and 3) when the tail gas discharged from the top of the reaction tower contains the fluoroxy trifluoromethane or the 1,2-difluoro-1,2-dichloroethylene content of the sampled analysis liquid phase is less than 1 volume percent by detection, terminating the reaction, and stopping introducing the gaseous fluoroxy trifluoromethane. The method has the advantages of low metering requirement, convenience of operation, long service life of equipment and high yield.

Description

technical field [0001] The invention relates to a preparation method of trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether. Background technique [0002] The method currently used to prepare trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether (CF3OCFClCF2Cl) generally uses a gas phase reaction: the gas phase of fluorooxytrifluoromethane (CF3OF) 1,2-difluoro-1,2-dichloroethylene (CFCl= CFCl) in the gas phase is continuously fed from one end of the reaction tower at a molar ratio of about 1:1, so that the two are co-current in the reaction tower Contact and reaction to generate trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether. The disadvantages of this process are: 1) The two gas phases need to be measured strictly according to the ratio, which is not easy to operate ; Since the main content of fluorooxytrifluoromethane in the gas phase fluctuates in the range of 60% to 90%, the amount of fluorooxytrifluoromethane needs to be adjusted frequently, which is ...

AI Technical Summary

Problems solved by technology

[0002] The method currently used to prepare trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether (CF3OCFClCF2Cl) generally uses a gas phase reaction: the gas phase of fluorooxytrifluoromethane (CF3OF) 1,2-difluoro-1,2-dichloroethylene (CFCl= CFCl) in the gas phase is continuously fed from one end of the reaction tower at a molar ratio of about 1:1, so that the two are co-current in the reaction tower Contact and reaction to generate trifluoromethyl-1,2,2-trifluoro-1,2-dichloroethyl ether. The disadvantages of this process are: 1) The two gas phases need to be measured strictly according to the ratio, which is not easy to operate ; Since the main content of fluorooxytrifluoromethane in the gas phase fluctuates in the range of 60% to 90%, the amount of fluorooxytrifluoromethane needs to be adjusted frequently, which is not easy to operate, and the corrosion of fluorooxytrifluoromethane High reliability, resulting in short service life of metering equipment (such as rotors, etc.), and once the metering is inaccurate, no matter which material is excessive, its conversion rate will decrease; 2) In order to ensure that the two reactants are in the gas phase, the temperature must be controlled at 30 ° C Above, the reaction is an exothermic reaction. Due to the difficulty of heat transfer in the gas phase, the reaction temperature may reach 60°C-100°C. If the temperature is too high, a disproportionation reaction will occur, which will reduce the yield of the target product.