METHOD FOR ISOLATION OF 1-FLUORO-1,1-DICHLOROETHANE, 1,1-DIFLUORO-1-CHLOROETHANE, 1,1,1-TRIFLUOROETHANE AND HYDROGEN CHLORIDE FROM GAS SYNTHESIS Russian patent published in 2005 - IPC

FIELD: chemical technology.

SUBSTANCE: invention relates to a method for isolation of 1-fluoro-1,1-dichloroethane, 1,1-difluoro-1-chloroethane, 1,1,1-trifluoroethane and hydrogen chloride from reaction mixture prepared by synthesis of vinylidene chloride and hydrogen fluoride. Process involves separating for layers and rectified separation. Gaseous mixture synthesis consisting of 1-fluoro-1,1-dichloroethane, 1,1-difluoro-1-chloroethane, 1,1,1-trifluoroethane, hydrogen fluoride and hydrogen chloride is absorbed with liquid mixture of substances prepared after separating for layers. The liquid mixture of substances comprises hydrogen fluoride, 1-fluoro-1,1-dichloroethane and 1,1-difluoro-1-chloroethane. Gaseous substances are fed for rectified separation and distillate obtained after rectifying that comprises hydrogen chloride and 1,1,1-trifluoroethane is fed for rectified separation and 1,1,1-trifluoroethane is recovered inversely for rectification in the amount determined by temperature and pressure values of the distillate condensation process. Vat product containing hydrogen fluoride, 1-fluoro-1,1-dichloroethane and 1,1-difluoro-1-chloroethane is fed for separating for layers and then prepared hydrogen fluoride with impurities of organofluoric compounds is recovered for absorption as liquid spraying. Mixture enriched with 1-fluoro-1,1-dichloroethane, 1,1-difluoro-1-chloroethane and containing hydrogen fluoride is fed for rectification wherein hydrogen fluoride as a component of mixture with 1,1-difluoro-1-chloroethane that is similar by the content of components to azeotropic mixture is separated and recovered its for repeated separating for layers and rectification. After repeated separation hydrogen fluoride is recovered for the synthesis. Mixture of 1-fluoro-1,1-dichloroethane and 1,1-difluoro-1-chloroethane is fed for rectified separation. Method provides increasing yield of commercial products as result of evolving gases synthesis of vinylidene chloride and hydrogen fluoride, simplifying the process and prevents accumulation of by-side products in the process.

EFFECT: improved method for isolation.

2 cl, 1 dwg, 4 ex