The mechanism of conversion of hydrocarbons on sulfated metal oxides. Part II. Reaction of benzene on sulfated zirconia [1]

The conversion of benzene on sulfated zirconia was studied in batch reactor, under mild conditions. The interaction of benzene with the catalyst is a complex process which is initiated by a one-electron oxidation, followed either by trapping of the generated cation-radicals to form sulfite esters on the surface, or by the reaction of the cation-radicals with the excess of benzene, followed by a cascade of coupling and cleavage reactions. The surface esters liberate phenol upon hydrolysis at the end of the reaction. Thus, benzene is retained on sulfated zirconia not because of protonation to benzenium ion, but because of formation of non-volatile products.