The Preparation of a Residue-free, Alumina-supported Gold Catalyst by Decomposition of an Azido-Gold(III) Complex and an Evaluation of the Effectiveness of the Catalyst for the Hydrogenation of Propyne

A 1 % w/w alumina-supported gold catalyst is described that is prepared from the impregnation of alumina with a solution of ammonium tetraazidoaurate(III), NH4[Au(N3)4]. Decomposition of the azide precursor leads to a residue-free catalyst comprised of well-dispersed gold particles. This novel material is tested for propyne hydrogenation using pulse-flow techniques and displays 100 % selectivity to the partial hydrogenation product, propene, albeit in the presence of a large retention of hydrocarbon by the catalyst. The latter characteristic is associated with a support-mediated deactivation pathway. Comparing catalytic performance with a 1.45 % w/w Au/TiO2 reference catalyst indicates that chlorine-free precursor compounds are not required to enhance catalytic activity for this particular reaction.