Catalytic performance of a novel Cr/ZnAlLaO catalyst for oxidative dehydrogenation of isobutane

Abstract

The oxidative dehydrogenation of isobutane using a chrome-based catalyst supported on a novel ZnAlLaO mixed oxide was investigated. The characterization and performance of Cr/ZnAlLaO catalysts were compared with those of several traditional catalysts. The Cr/ZnAlLaO catalyst showed the best selectivity and conversion rate with the highest stability. The performance of the Cr/ZnAlLaO catalyst strongly depends on the Cr content and support properties. The activity peak of isobutane oxidative dehydrogenation occurs at 18 wt% of Cr₂O₃ loading. The selectivity and conversion of isobutene reach their maximum at 84.07% and 52.44%, respectively. Correlation was observed between coke formation and catalyst deactivation. Moderate alkalinity on the ZnAlLaO support surface is helpful to suppress coke formation as well as to improve the catalytic activity and stability. Appropriate water vapour addition to the feed can improve catalytic stability, while both the selectivity of isobutene and the conversion of isobutane decreased.