Reduction activities of Fe₂O₃ SiO₂ catalysts with hydrogen sulphide and hydrogen

Diphenylmethane and diphenylether were reacted under a H₂ H₂S gas mixture in the presence of a series of Fe₂O₃ SiO₂ catalysts. In general, the activity of Fe₂O₃ SiO₂ increased as the surface area increased, but decreased when the catalyst preparation involved the use of sodium hydroxide or sulphate ions. The supported iron catalysts displayed higher activity, in terms of conversion, toward the aromatic-alkyl (Ar-C) bond cleavage than the aromatic-ether (Ar-O) bond cleavage. Some of the Fe₂O₃ SiO₂ catalysts were more effective than MoO₃ CoOAl₂O₃ for cleaving diphenylmethane and did so with less aromatic ring hydrogenation. The hydrocracking ability with regard to the Ar-C bond rupture correlated well with the acidity of the catalysts as determined by butylamine adsorption. Both hydrocracking and hydrogenation abilities of the catalysts were important in the Ar-O bond rupture which appeared to be influenced by acid and base sites.