process of preparation of the development of difluorochlorobromomethane

摘要

1,259,077. Difluorochlorobromomethane. KALI-CHEMIE A.G. 18 Aug., 1970 [13 Sept., 1969], No. 39774/70. Heading C2C. The invention comprises a process for producing difluorochlorobromomethane wherein difluoromonochloromethane is reacted in a reactor with excess bromine at 300-650‹ C., and the bromine and hydrogen bromide formed are removed from the product, the difluorochlorobromomethane being separated from the other components by fractional distillation, and either wherein difluorodibromomethane which forms as a by-product is continuously taken to a separate reactor, reacted therein with chlorine, whilst maintaining a molar ratio of difluorodibromomethane to chlorine of 1 : 0À1 to 1 : 2À0 at 300-600‹ C. and a residence time of 0À5-10 seconds, the reaction products thus obtained being then combined with the reaction products leaving the bromination reactor or wherein the difluorodibromomethane by-product is continuously recycled into the bromination reactor, chlorine being simultaneously added to the reaction mixture to maintain a molar ratio of chlorine to (CF 2 Br 2 + CHF 2 Cl) of 0À1 to 0À6 : 1.