Hydrogenation of five-membered heterocycles of polymer-supported palladium catalyst at normal temperature and pressure

To modify the surface of aminomethyl polystyrene, grafting of hyperbranched dendritic polyamidoamine, a new class of topological macromolecules, onto the surface was investigated. It was found that hyperbranched dendritic polyamidoamine was propagated from aminomethyl polystyrene surface by repeating two processes: (1) Michael addition; (2) amidation. Furthermore, salicylal (SA) readily postgrafted to the hyperbranched dendritic polyamidoamine-grafted-aminomethyl polystyrene. Finally, catalytic hydrogenations of pyrrole, furan and thiophene were investigated by the modifying polyamidoamine-grafted aminomethyl polystyrene with SA (MPGAPS)-supported palladium catalyst. The double-bond of the ring was hydrogenated to single-bond ring of tetrahydro-compound at first, then the ring is broken directly. In general, these reactions were degradation under reduction. UV absorbance spectroscopy, gas chromatography (GC), and power of hydrogen (PH) detection were used to analyze the reactants and products, and infrared (IR), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) characterized the catalyst. Copyright (C) 2004 John Wiley Sons, Ltd.