Study of the reaction conditions for the hydrodechlorination of pentachlorophenol on palladium catalysts

Catalytic hydrodechlorination has been intensely studied recently since it seems to be a promising method for treating toxic organochlorine residues. In this context, the aim of this work is to study the reaction conditions for pentachlorophenol hydrodechlorination, conducted in a three-phase media with palladium catalysts. The study was carried on a commercial Pd/C catalyst and a Pd/TiO 2 catalyst, which was prepared by the dry impregnation technique from the PdCl 2 precursor. Preliminary catalytic tests indicated that for both catalysts, previous reduction significantly reduced their catalytic activities, while calcination at 573 K leads to active catalysts in the reaction. Owing to the undesirable retention of pentachlorophenol observed using the Pd/C catalyst, the Pd/TiO 2 system was used to study reaction conditions by means of a 2 6−2 fractional factorial design. One combination of levels of this design permitted establishing suitable reaction conditions for this hydrodechlorination.