Oxidation of Propylene over the Tin-Antimony Oxide Catalysts. I. Dependency of Acrolein Formation on the Composition of Catalyst and Calcination Conditions

Abstract

Abstract For the purpose of elucidating the catalysis of the binary system consisting of Sn and Sb oxides, recommended in the patent for the oxidation of propylene to acrolein, the oxidation of propylene has been studied; in addition, the X-ray patterns of the system have been investigated. The mixtures of this binary system after sintering were different in color according to the catalyst composition and the calcination conditions. It was found that the color of the catalyst is closely connected with the formation of acrolein, and also that the blue-colored catalysts are effective in the selective production of acrolein. The pure tin oxide catalyst yielded mainly carbon dioxide and monoxide, while the pure antimony yielded scarcely any product. However, a selectivity to acrolein of more than 70% was obtained at 450°C over a catalyst with an optimal composition, for example, one with a Sn to Sb atomic ratio of 3 : 1 which had been calcined at 1000°C for 3 hr. The formation of acrolein was investigated as a function of the catalyst composition and the calcination conditions. According to the X-ray data, Sb oxide was soluble in Sn oxide, thus forming solid solutions, and the mixtures’ becoming colored was attributable to the formation of the solid solutions. It was concluded that the formation of acrolein over this binary system is closely connected with the solid solutions formed between Sn and Sb oxides.