Decomposition of chlorofluorocarbons over metal phosphate catalysts -: Part I.: Decomposition of CCl2F2 over metal phosphate catalysts

In the decomposition of chlorofluorocarbons (CFCs), HF produced in the decomposition reacts with and deactivates the catalyst. Metal phosphates were chosen as the catalyst from Delta G calculations. Zr-P-O and AlPO4 showed high catalytic activity for the decomposition of CCl2F2 above 350 degrees C. The essential reaction of the decomposition is hydrolysis. On increasing the CCl2F2 concentration in the feed, the formation of CClF3, as a by-product is promoted. AlPO4, has both weak acid sites and those of intermediate strength and these acid sites may participate in the hydrolysis of CCl2F2. No reaction between AlPO4 and formed HF was observed during 1000 h reaction at 400 degrees C, AlPO4 promises to be of practical use.