| 摘要 |
<p>A process for the production of 1,1-difluoroethylene by photochlorinating 1,1-difluoroethane to form 1,1-difluoro-1-chloro-ethane and heating the reaction products obtained to temperatures of from 550 to 750.degree.C. The process is characterised in that the difluoroethane used is an unpurified reaction product of the catalytic hydrofluorination of acetylene and contains up to 3 % by volume of acetylene and at most 8 % by volume of vinyl fluoride. Despite the presence of impurities, namely acetylene and vinyl fluoride, in the starting product, yields of 1,1-difluoroethylene amounting to more than 90 %, based on the acetylene used, are obtained where this process is applied. Accordingly, the secondary products present, particularly the unreacted acetylene, have hardly any effect upon the reaction as a whole. This is surprising insofar as it was not known that gas mixtures containing acetylene could be photochlorinated without difficulty.</p> |
