Catalytic hydrodechlorination of p-chloro-m-cresol and 2,4,6-trichlorophenol with Pd and Rh supported on Al-pillared clays

摘要

Hydrodechlorination (HDC) of p-chloro-. m-cresol (PCMC) and 2,4,6-trichlorophenol (246TCP) under ambient-like conditions (25. °C, 1. atm) with Pd and Rh supported on Al-pillared clays (Al-PILC) has been studied. The two target pollutants were completely converted into biodegradable products with both catalysts in short reaction time. The Pd catalyst was selective towards m-cresol and 3-methyl-cyclohexanone in the HDC of PCMC and to phenol and cyclohexanone in the case of 246TCP. The Rh catalyst showed a high hydrogenating activity leading to the formation of 3-methyl-cyclohexanol and cyclohexanol as final products of the HDC of PCMC and 246TCP, respectively. This led to a dramatic decrease of ecotoxicity. The dechlorination of PCMC at short reaction times allowed a high improvement of the biodegradability whereas increasing the reaction time favors the formation of highly hydrogenated byproducts, like 3-methyl-cyclohexanone and 3-methyl-cyclohexanol, which showed a lower biodegradability. A kinetic study of the HDC of PCMC and 246-TCP with the two mentioned catalysts is also presented