Kinetics of the deep oxidation of benzene, toluene, n-hexane and their binary mixtures over a platinum on γ-alumina catalyst

Abstract

In this work, the catalytic oxidation of benzene, toluene and n-hexane in air, both alone and in binary mixtures, over a commercial Pt on γ-alumina catalyst was studied. Studies have been carried out at concentrations of up to 4200ppmV, in a laboratory fixed-bed catalytic reactor.Results for single compounds show that temperature at which 50% conversion is attained (T50) increases as concentration increases for benzene and toluene, while the opposite behaviour is observed for n-hexane. Results for mixtures show that, while the presence of n-hexane does not affect the conversion of benzene and toluene, the presence of benzene or toluene inhibits the combustion of hexane, and the aromatic compounds inhibits each other when are reacted together.Results obtained in absence of mass transfer limitations were fit to kinetic expressions: simple Mars–Van Krevelen kinetic expressions for single compounds, and a modified Mars–Van Krevelen mechanism, considering competitive adsorption of the hydrocarbons, for binary mixtures.