Behandlung von Chromoxid und dessen Verwendung in der katalytischen Herstellung von Vinylfluorid

摘要

Advantageous processes are disclosed for the production of vinyl fluoride. Also disclosed are advantageous methods which may be employed for the preparation of catalysts useful in such processes. Included is a method which involves reducing surface B2O3 present in a bulk chromium oxide composition containing surface B2O3 by treating said composition with HF at an elevated temperature. Processes are provided herein which involve contacting 1,1-difluoroethane in the vapor phase with a trivalent chromium catalyst having primarily the morphology of alpha-chromium oxide and optionally containing less than 1000 ppm alkali metal as the alkali metal oxide wherein chromium is at least 95 atom percent of the metallic cations of said catalyst, at a temperature between about 225 DEG C and 375 DEG C. Advantageous embodiments of these processes are disclosed wherein (i) the catalyst is prepared by reducing B2O3 present in a bulk chromium oxide composition as indicated above, (ii) chromium is at least 99 atom percent of the metallic cations of the catalyst and/or (iii) the space velocity is from about 200 volumes to 2000 volumes of 1,1-difluoroethane per volume of catalyst per hour.