Coupling of 1,4-Butanediol Dehydrogenation with Nitrobenzene Hydrogenation for Simultaneous Synthesis of gamma-Butyrolactone and Aniline over Promoted Cu-MgO Catalysts: Effect of Promoters

Abstract

The promotional effect of various transition metal oxides such as Co3O4,Cr2O3 and ZnO with different loadings was studied on Cu-MgO for coupling of 1,4-butanediol dehydrogenation and nitrobenzene hydrogenation for the simultaneous synthesis of gamma-butyrolactone and aniline under hydrogen free environment. All the catalysts were developed (xM-20Cu-(80-x)MgO where M = Co3O4, Cr2O3, ZnO and x = 1 and 10 wt%) by precipitation-hydroxycarbonate gel mixing method. The promotional effect of transition metal oxides with various loadings on Cu-MgO catalyst revealed that the apparent changes in the parent solid structure and texture improved the catalytic actvity of xM-20Cu-(80-x)MgO. Interestingly, the results of the promotinal effect of cobalt oxide on Cu-MgO are excellent compared to that of Cr2O3 and ZnO promoters. The high yields (> 90%) of gamma-butyrolactone and aniline were observed over 10Co(3)O(4)-20Cu-70MgO catalyst. The N2O pulse chemisoprtion analysis of the catalysts revealed that cobalt oxide containing Cu-MgO exibited high dispersion with smaller particle size of the copper (similar to 22 nm). Moreover, XPS analysis also proved the presence of more surface Cu-0 species and CHNS analysis confirmed the coke resistance of the cobalt oxide promoted Cu-MgO catalysts compared to that of Cr2O3 and ZnO promoted Cu-MgO.