A palladium tetra-coordinated complex as catalyst in the selective hydrogenation of 1-heptyne

Supporting on gamma-Al2O3 a palladium complex with chloride and tridecylamine as ligands, it is possible to obtain an heterogeneous catalyst which is more active and selective for the 1-heptyne hydrogenation to 1-heptene than the classic Lindlar catalyst. At the same operational conditions, the supported palladium complex is also more active and selective than the same complex unsupported. The hydrogen pressure and the operational temperature showed to play an important role in the catalytic behavior of the catalysts under study. As determined by FTIR and X-ray photoelectron spectroscopy (XPS), the active species is the complex itself, which is stable under the reaction conditions. The obtained XPS results show that the palladium complex, supported or not, is tetra-coordinated, suggesting that its formula is [PdCl2(NH2(CH2)(12)CH3)(2)]. The highest activity and selectivity of the palladium supported complex can be attributed, at least partially, to electronic and geometrical effects. (C) 2002 Elsevier Science B.V. All rights reserved.