| abstract |
Manufacture of 1,1,1,2-tetrafluoroethane by reacting 1,1,1-trifluoro-2-chloroethane with hydrogen fluoride in the presence of a chromium oxide catalyst and removing 1,1-difluoro-2-chloroethylene contaminant from the resulting impure asym tetrafluoroethane product by passing the impure product with hydrogen fluoride over a chromium oxide catalyst at much lower temperatures than are used in the manufacturing process. |