Analysis of deactivation and selectivity pattern in catalytic hydrogenation of a molecule with different functional groups:: crotonaldehyde hydrogenation on Pt/SnO2

Hydrogenation of crotonaldehyde was studied in the gas phase, at atmospheric pressure and 353 K over 5% Pt/SnO2 catalysts, prepared from Pt(NH3)(4)(NO3)(2) and H2PtCl6. Rapid deactivation during time on stream was observed. Experiments were performed consecutively in a series using a catalyst reduction pretreatment between kinetic runs. Selectivity was found to be dependent on ageing period and on the metal precursor. Selectivity as high as 70% until 40% conversion was observed using Pt(NH3)(4)(NO3)(2) as precursor. Adsorption and hydrogenation of the C=O and C=C groups are supposed to occur on different sites, which have different deactivation properties. Kinetic model is advanced to describe deactivation and selectivity patterns. (C) 2002 Published by Elsevier Science Ltd.