A systematic investigation of the oxidation of 1,2-dichlorobenzene (o-
DCB) was conducted over a series of vanadia/titania catalysts with dif
ferent V2O5 loadings (i.e. 0.8, 3.6 and 5.8 wt%). The TiO2 support was
also found to be active for this reaction, but its activity was signi
ficantly lower than that of the surface vanadia species. Reaction rate
s per vanadium atom (i.e. turnover frequencies) were calculated for th
ese catalysts and found to be independent of the vanadia coverage. Kin
etic measurements showed that under excess oxygen conditions, the reac
tion is approximately first order in o-DCB and zero order in oxygen. C
arbon monoxide and carbon dioxide were the only products detected. The
selectivity towards CO was approximately 40-45% and was found to be i
ndependent of vanadia loading and temperature. No deactivation of the
catalyst was observed even after 100 h of operation at 723 K. Addition
of WO3, MoO3 and ZnO to the V2O5/TiO2 system was found to have no sig
nificant effect on its activity for o-DCB oxidation. (C) 1998 Elsevier
Science B.V.