Bi modified Pd/support (SiO2, Al2O3) catalysts for hydrodechlorination of 2,4-dichlorophenol

The influence of bismuth addition on the activity and selectivity of home-made supported palladium catalysts in the reaction of hydrodechlorination of 2,4-dichlorophenol to phenol was studied. Bimetallic Pd-Bi/Al2O3 and Pd-Bi/SiO2 catalysts, containing 5 wt.% of Pd and 1-5 wt.% of Bi, are characterized by high conversion of 2,4-dichlorophenol. which reaches about 100% at the end of the reaction run. However, the catalysts 5%Pd-8%Bi/SiO2 and 5%Pd-8%Bi/Al2O3 show considerably lower conversion (respectively, about 25% and 60%), but they are characterized by the highest selectivity towards phenol (respectively, about 95% and 60%). The stability of the chosen bimetallic catalyst 5%Pd-1%Bi/Al2O3 is higher than that of the monometallic palladium catalyst. The XRD and ToF-SIMS studies proved the presence of intermetallic compounds BiPd and Bi2Pd, which probably modify the catalytic properties of Pd-Bi/support catalysts in hydrodechlorination of 2,4-dichlorophenol. (C) 2010 Elsevier B.V. All rights reserved.