Hydrodechlorination of CFC-12 over Fluorinated Pd/Al₂O₃ Catalyst

The hydrodechlorination of CFC-12(CF2Cl2) has been studied with Pd/Al2O3 catalysts. The catalysts were fluorinated by HCFC-22(CHF2Cl) or reduced by hydrogen before the reaction. And they were characterized by BET, XRD, and TEM before and after the reaction. The activities and selectivities to HFC-32(CH2F2) were compared in the fluorinated and the reduced catalysts. The fluorinated catalyst has shown better performance in activity and selectivity rather than the conventional reduced one, as well as in prevention of Pd sintering which causes deactivation of the catalyst. It is presumed that formation of Pd-F bond in the fluorination prevents sintering of Pd while the formation of AlF3 from Al2O3. Also, Pd carbide was observed in the fluorinated catalyst and this carbide is thought to enhance the partial dehalogenation(dechlorination) in CFC-12.