Study on olefin oxidation by periodic-pulse technique: II. Oxidative dehydrogenation of 1-butene using various oxide catalysts

Abstract

The oxidative dehydrogenation of 1-butene proceeds with a higher selectivity than does the oxidation of propylene. Butadiene and 2-butenes are shown to be produced by the reactions between gaseous 1-butene and surface oxygen. Carbon oxides are formed between the adsorbed residue and oxygen from the gas phase in the BiMo oxide catalyst. Some of the active sites over the BiMo and BiW oxide catalysts seem to be inhibited by the poisoning of the adsorbed residue at a higher partial pressure of 1-butene. The rate of isomerization in the continuous-flow technique is smaller or greater than that in the periodic-pulse technique for reducible catalysts like SnP and BiW oxides, or for oxidizable ones like SnSb and SbMo oxides, respectively. An intermediate trend is notable in BiMo oxide and MoO 3. It follows that the catalysts used in this experiment can be placed in this order with regard to the reducibilities of the catalyst; BiW SnP MoO 3 BiMo SnSb SbMo where the more to the left the catalyst lies, the more easily it can be reduced. This is supported by the partial pressure dependence in the periodic-pulse technique and by the variation in the rate of isomerization with the pulse number in the one-shot pulse technique. The results in the oxidative dehydrogenation of 1-butene were similar to those in the oxidation of propylene reported previously. It seems that isomerization takes place via the allyl intermediate.