Patent ID: 7982074

Claim:
A process for the preparation of 1,1,1,2-tetrafluoroethane (HFC-134a) from trichloroethylene (TCE), the said process comprising the steps of: a) fluorinating trichloroethylene (TCE) with anhydrous hydrogen fluoride (AHF) by contracting with a co-precipitated Cr 2 O 3 /Al 2 O 3 catalyst promoted by Zn salt, to obtain an intermediate 2-chloro-1,1,1-trifluoroethane (HCFC-133a), and b) fluorinating the product of step (a) with anhydrous hydrogen fluoride (AHF) in presence of co-precipitated Cr 2 O 3 /AlO 3 catalyst promoted by Zinc salt, to yield the required product 1,1,1,2-tetrafluoroethane (HFC-134a), wherein a W/F value is in the range of 80-150; wherein the co-precipitated Cr 2 O 3 /Al 2 O 3 catalyst promoted by zinc salt is prepared by a process comprising co-precipitation of chromium and aluminum metal hydroxides from corresponding trivalent metal salt solutions using NH 4 OH, NaOH or KOH as a base and followed by calcination at 400° C. at 24 hours to provide a mixed oxide precatalyst in amorphous form, wherein the ratio of Cr:Al is in the range of 1:1 to 1:14, which is then impregnated using the Equilibrium Adsorption Method with an activity promoting amount of zinc compound, and then thermally treated at 90° C.