Effect of the zeolite content on the hydrodenitrogenation of 1,2,3,4-tetrahydroquinoline over sulphided NiMo on alumina catalysts

Abstract The catalytic hydrodenitrogenation of 1,2,3,4-tetrahydroquinoline was studied on nickel and molybdenum sulphides supported on alumina-zeolite mixtures. Different ratios (number of acid sites)/(number of hydrogenating sites) were obtained by varying the weight of the zeolite in the support. The results obtained indicate the existence of an optimal ratio (number of acid sites)/(number of hydrogenating sites), hence of an optimal distance between both types of sites, for which the decahydroquinoline formed on the hydrogenating sites shifts rapidly on the neighbouring acid sites and cracks into the desired reaction product (propylcyclohexane). The corresponding catalyst exhibits a selectivity for hydrodenitrogenation much higher than classical NiMo on alumina catalysts.