Abstract: An improvement in a method of preparing 1,1-difluoroethylene from 1,1-difluoroethane by photochlorinating 1,1-difluoroethane to 1,1-difluoro-1-chloroethane and immediately thereafter reacting the reaction products of the photochlorination at a temperature between 550 and 750.degree. C. without isolation of the 1,1-difluoro-1-chloroethane, the improvement residing in employing as the difluoroethane charge an unrefined product of the hydrofluorination of acetylene which unrefined reaction product contains up to 3 volume percent acetylene and a maximum of 8 volume percent vinyl fluoride, especially a unrefined reaction product in which the difluoroethane has not been isolated.

Abstract: A process for preparing 1,1-difluoroethane by contacting acetylene with hydrogen fluoride in the presence of an aluminum fluoride containing catalyst, the hydrofluorination being carried out at a temperature between 150 and 350.degree. C. employing a residence time of one to 60 seconds. The catalyst employed is one prepared by imbibing gamma or eta aluminum oxide with a solution of a bismuth salt and a manganese salt. The so-imbibed catalyst is heated at a temperature between 150 and 250.degree. C. initially in a nitrogen atmosphere and then, after complete drying, in a mixture of air employing increasing concentrations of hydrogen fluoride up to 100 percent hydrogen fluoride atmosphere. The finished catalyst contains:0.1 to 20 weight percent of bismuth,0.1 to 10 weight percent of manganese,20 to 38 weight percent of aluminum,32 to 60 weight percent of fluorine,The balance consisting essentially of oxygen.

Abstract: A process for the purification of contaminated 1,1,1-trifluoro-2-chloro-2-bromoethane by reaction of the compound with organic amines, yielding 1,1,1-trifluoro-2-chloro-2-bromoethane of sufficient purity for use as an anaesthetic.

Abstract: Improvement in the catalytic hydrofluorination of halogenated hydrocarbons by carying out the hydrofluorination with a catalyst which is 0.1 to 20 wt. % bismuth, 35 to 66 wt. % fluorine, 24 to 42 wt. % aluminum, and the remainder oxygen. A preferred catalyst also contains manganese.