METHOD OF PRODUCTION OF DIFLUOROCHLOROMETHANE Russian patent published in 2003 - IPC

FIELD: chemical industry, technology of fluorochlorohydrocarbons production. SUBSTANCE: invention presents the method of production of fluorochlorohydrocarbons, in particular - difluorochloromethane (chladone 22, R22, HCFC 22), used as the ozone-safe refrigerant, propellent, porophore, raw material for production of fluorine-monomers. The method is realized by hydrofluorination of chloroform by vaporized fluorine hydride at the presence of the catalyst - pentachlorated antimony with the additive of chlorine. The reaction gases are wash out with water and obtain the concentrated hydrochloric acid, the residual amount of the sour components is neutralized, compressed, condensed. The target product is produced by rectification of the condensation moisture. The shell still fraction is exposed to azeotropic dehydration with evacuation of the water present in the shell still fraction to the shell still head part. The dehydrated residual is rectified with extraction of difluorochloromethane and the neutral chloroform, that are to be returned on a stage of hydrofluorination. Processing of the shell still fraction is preferable to conduct under atmospheric pressure, and its dehydration - at 15 - 30 C, and rectification of the dehydrated residual - at 55 - 85 C. EFFECT: effect(result) - decrease of deactivation of the catalyst, decrease of environmental impact. 2 cl, 1 tbl