Kinetics and mechanism of oxidation of butene isomers over a tin oxide + antimony oxide catalyst

Abstract

Detailed studies have been made of the kinetics of the oxidation of n-butene isomers to butadiene over a tin oxide + antimony oxide catalyst. Values of energies of activation and orders of reaction are reported for the oxidation of n-butene isomers to butadiene, carbon dioxide and minor oxygenated products. The results are consistent with a reaction mechanism in which extraction of an allylic hydrogen by oxidic oxygen from an adsorbed butene molecule is rate determining. It is suggested that the reaction occurs over solid solutions of Sb₂O₅ in SnO₂, in which Sn⁴⁺ ions play an important role. The formation of minor products is discussed.