PALLADIUM BLACK AS MODEL CATALYST IN THE HYDROGENOLYSIS OF CCL2F2 (CFC-12) INTO CH2F2 (HFC-32)

Palladium black is applied as a model catalyst for the hydrogenolysis of CCl2F2 into CH2F2 over carbon supported palladium. The performance of palladium black is comparable with that of palladium on activated c arbon. Fresh and used samples are characterized with X-ray diffraction (XRD), temperature programmed reduction (TPR), and temperature progra mmed oxidation (TPO) in a differential scanning calorimeter (DSC). Und er reaction conditions, at temperatures as low as 423 K, palladium is converted into palladium carbide (PdC0.15). The amount of carbon on th e catalytic surface is negligible. Fluorine present has no catalytic e ffect. Methane treatment (>523 K) and ethene treatment (>448 K) also l ead to the formation of palladium carbide. In those cases carbon is de posited on the surface of the palladium. The amount of hydrogen in fre sh palladium, determined by measuring the temperature of decomposition of palladium hydride at different partial pressures of hydrogen and b y measuring the heat of decomposition in DSC, is as PdH0.6. This amoun t is in agreement with the value as obtained by TPR and as reported in literature.