Oxidation of 1-Butene over Multi-Component Oxide System Containing Molybdenum

Abstract

The catalytic activity of multi-component oxide systems containing Mo, especially Mo-Bi and Mo-Bi-Ba oxide systems, in vapor phase oxidation of 1-butene has been studied in connection with the method of preparation and structure of the catalyst. The catalytic oxidation was performed at 470°C, with 17% 1-butene in air. X-ray, IR and thermal analyses were made in order to identify the structure of the catalyst.Mo-Bi oxide catalyst prepared from an acidic mixture of raw materials, containing NO3 ion, has high activity for diene formation and contains a chemical compound whose structure is thought to be Bi2MoO6. Mo-Bi-Ba system catalyst made from a mixture of Mo, Bi and Ba compounds with excess of NO3 ion, containing Ba(NO3)2 and the above mentioned structure shows also high activity for diene .formation and, moreover, maintains this activity even after the escape of nitrogen oxide during the reaction.It is thought that there is an important correlation between the existence of Bi2MoO6 and activity for diene synthesis.Mo-Bi oxide catalyst prepared from a basic medium containing excess of ammonia and Mo-Bi-Ba oxide catalyst made by adding Ba(OH)2 to the Mo-Bi oxide system have some catalytic activity in which the carbon oxides formation is predominant. It has been considered that the structure of Bi4MoO9 is contained in the former catalyst and BaMoO4 in the latter, and these compounds have high selectivity for formation of carbon oxides or isomers.Mo-As-X oxide catalyst (X: alkaline earth metal) shows also high activity for diene synthesis; however, considerable differences exist between the effects of adding X to the Mo-Bi system and to the Mo-As system.