Activity and product distribution of alumina supported platinum and palladium catalysts in the gas-phase oxidative decomposition of chlorinated hydrocarbons

The complete catalytic oxidation of 1,2-dichloroethane (DCE) and trichloroe thylene (TCE) over alumina supported noble metal catalysts (Pt and Pd) was evaluated. Experiments were performed at conditions of lean hydrocarbon con centration (around 1000 ppm) in air, between 250 degrees C and 550 degrees C in a conventional fixed bed reactor. The catalysts were prepared in a ran ge of metal contents from 0.1 to 1 wt%. Palladium catalysts resulted to be more active than platinum catalysts in the oxidation of both chlorinated vo latile organic compounds. DCE was completely destructed at 375 degrees C, w hereas TCE required 550 degrees C. HC1 was the only chlorine-containing pro duct in the oxidation of DCE in the range of 250-400 degrees C. Tetrachloro ethylene was observed as an intermediate in the oxidation of TCE, being; fo rmed to a significant extent between 400 degrees C and 525 degrees C. CO wa s also detected in the oxidation of both DCE and TCE over Pd catalysts, tho ugh at temperatures of complete destruction, CO<INF>2</INF><SUP></SUP> was the only carbon-containing product. The Pt catalysts were selective to CO<I NF>2</INF> at the studied contionons. (C) 1998 Elsevier Science B.V. All ri ghts reserved.