For the preparation of HFC-134a, the isomerization of CFC-114 and the gydrogenation of CFC-114a were investigated. Both reactions were catalyzed by AlCl₃ catalyst. both isomerization reactions proceeded after a certain induction period probably because the catalyst needed the activation by the halogen exchange. The catalyst deactivated gradually with the time on stream. However, the deactivation rate could be reduced by removing impurities from the reactants. Isomerization rate of CFC-114 was much slower then of CFC-113, falladium supported on carbon catalyzed the hydrogenation reaction quite selective while the selectivity declined when the supper was replaced with different supports. The catalytic activity and selectivity to desired products increased in the following order. Pd/kisslguhr<Pd/silica-alumina =~Pd/silica gel<Pd/TiO₂<Pd/Al₂O₃<Pd/C