Mild oxidation of bulky organic compounds with hydrogen peroxide over mesoporous TiO2-SiO2 xerogels prepared by non-hydrolytic sol–gel

Abstract

The oxidation of bulky organic compounds with aqueous H2O2 over a TiO2-SiO2 xerogel catalyst prepared by a simple non-hydrolytic sol–gel route is described for the first time. Anthracene, cyclooctene, styrene, α-naphtol, diphenyl sulfide, dibenzothiophene and 4,6-dimethyl-dibenzothiophene were oxidized with high activity, selectivity and H2O2 efficiency at moderate temperatures (40–60°C). Moreover, a similar catalytic behavior was observed when tert-butyl hydroperoxide (TBHP) was used as an oxidizing agent. These excellent catalytic performances were ascribed to the unique texture of the catalyst (specific surface area 1200m2g−1, pore volume 2.4cm3g−1, average pore diameter 15nm) and to the stability of Ti sites after exposure to aqueous H2O2 or TBHP.