Palladium hydrotalcites as precursors for the catalytic hydroconversion of CCl2F2 (CFC-12) and CHClF2 (HCFC-22)

The synthesis of palladium hydrotalcite-like materials and their catalytic properties for the hydroconversion of CCl2F2 (CFC-12) and CHClF2 (HCFC-22) are reported. These materials appear to be interesting catalysts for selective hydrodechlorination reactions. The influence of process parameters, such as reaction temperature and H2/CFC-HCFC ratio on the hydrogenolysis of CFC-12 and HCFC-22, has been investigated. In the reaction of CCl2F2, the main products were CH2F2, CH4 and CHClF2. In the reaction of CHClF2, the main products were CH2F2, CHF3 and CH4. The highest conversion and selectivity to CH2F2 are obtained on the heavily loaded Pd catalyst. A high H2/CFC-HCFC ratio favors the obtention of CH2F2. During the reaction, the formation of fluoride and Pd-carbide phases were detected.