Selective catalytic oxidation of aniline to azoxybenzene over titanium silicate molecular sieves

Abstract

The oxidation of aniline using aqueous H202 and titanium silicates, TS-1 and TS-2 as catalysts was carried out in a batch reactor in the temperature range 333-353 K. TS-1 catalyzes aniline selectively to azoxybenzene and is superior to TS-2. The influence of different solvents, concentration of H202 and the catalyst in the reaction mixture on the conversion and product distribution has been studied. Acetonitrile is a suitable solvent in this reaction, while acetone is not. For the TS-1 catalyzed oxidation reaction, t-butyl hydroperoxide is not a suitable oxidant. At optimum conditions, a H202 efficiency of about 100% for aniline conversion is obtained with a selectivity of 97% to azoxybenzene in the product.