| abstract |
A method for the purification of pharmaceutical grade 1,1,1,2-tetrafluoroethane (HFC-134 a ) and polymer grade chlorodifluoromethane (HCFC-22) by contacting a mixture containing 1,1,1,2-tetrafluoroethane or chlorodifluoromethane and methyl chloride with a zeolite such as a molecular sieve, and recovering from said contacted mixture substantially purified 1,1,1,2-tetrafluoroethane or chlorodifluoromethane. |