Coupling of ortho-chloronitrobenzene hydrogenation with 1,4-butanediol dehydrogenation over Cu-MgO catalysts: A hydrogen free process

Abstract

Aiming at an efficient method for the hydrogenation of o-chloronitrobenzene to o-chloroaniline under hydrogen free environment, the reaction was coupled with 1,4-butanediol dehydrogenation over Cu-MgO catalysts containing various amounts of copper loadings (5-20 wt%). o-Chloroaniline and gamma-butyrolactone were the main products with the yield of 85% and 90%, respectively. The main advantage of the coupling process was that the hydrogenation reaction was conducted at the lower temperature (523 K) without external hydrogen supply when compared to the independent hydrogenation (648 K). Catalysts were characterized using various analytical techniques such as BET, XRD, N2O pulse chemisorption, TPR-H-2, XPS and CHNS analysis. From N2O characterization results, it was found that 10 wt% Cu-MgO catalyst containing more surface Cu species (Cu-0/Cu+1) showed a superior performance in the coupling process.