Preparation of Au-Pt-Sn catalysts for isobutane dehydrogenation

Using isobutane as the raw material,the production process of isobutylene has the advantages of providing the source of isobutylene and high utilization of isobutane. Catalyst is the key factor of isobutane dehydrogenation. At present,the researches at home and abroad focus on the catalysts using platinum-tin as the active components. There exists the problems of low conversion rate and easy deactivation. The supported nano-gold catalysts for CO oxidation show high catalytic activity at low temperature. On the basis of original platinum-tin catalyst,Au-Pt-Sn catalyst was prepared by adding the gold and the equivalent-volume impregnation method. The effects of Au on the conversion and selectivity over the catalyst for isobutane dehydrogenation was investigated. The performance of the catalyst was evaluated in a small size fixed bed stainless reactor under the condition of atmospheric pressure,reaction temperature 600 ℃,space velocity 2 400 h- 1and hydrogen atmosphere. The results showed that the addition of Au promoted the activity of the catalyst. Isobutene yield of more than 40% was attained under the condition of n(Au)∶ n(Pt) = 1. 0. The performance of the catalyst before and after regeneration was also investigated. It was found that after regeneration,the conversion of isobutane and the selectivity to isobutene were slightly lower than those before regeneration,so the catalyst could be recycled.