Chlorobenzene hydrodechlorination catalyst prepared via the pyrolysis of sawdust impregnated with palladium nitrate

摘要

(7% Pd)/C catalysts have been prepared by the pyrolysis of untreated sawdust and sawdust washed with an acid to remove of Group I and II metal impurities, both impregnated with palladium nitrate. Studies by transmission electron microscopy, X-ray photoelectron spectroscopy, and temperature-programmed reduction have demonstrated that the dominant palladium species in the catalysts is 2-5 nm Pd-0 particles, there is no PdO on the surface, and the catalyst bulk contains small amounts of larger (10-20 nm) PdO particles. The catalysts are active in chlorobenzene hydrodechlorination in a fixed-bed flow reactor and ensure 100% conversion of the substrate into benzene in the temperature range from 250 to 350A degrees C. At lower temperatures (150-200A degrees C), the catalyst containing calcium is the most active and the sample subjected to reduction after pyrolysis shows the lowest activity.