Effect of the Functional Group on the Hydrodechlorination of Chlorinated Aromatic Compounds over Pd, Ru, and Rh Supported on Carbon

The effect of a functional group on the hydrodechlorination chlorinated aromatic compounds on Pd/C, Ru/C, and Rh/C catalysts was studied in liquid phase at 30 degrees C and 2 kg/cm(2) of hydrogen pressure, using 200 ppm of the chlorinated organic compound. An effect of particle size on Pd catalysts was observed, small particles showed to be more resistant to the deposit of chloride from the reaction. The activity in the hydrodechlorination of organic compounds as a function of the functional group increases in the following order p-chlorophenol > p-chlorotoluene > p-dichlorobenzene. The activity in the hydrodechlorination of these molecules increases with the presence of donating groups as -CH3 and -OH. The p-chlorotoluene hydrodechlorination on Ru and Rh leads also to the hydrogenation of the aromatic ring (toluene, methylcyclohexane). On the other hand, the p-chlorophenol hydrodechlorination over Pd, Ru, and Rh produces deoxygenated products (chlorobenzene, phenol, and benzene). Pd showed the highest activity followed by Ru and Rh.