Preparation, characterization and application of platinum catalysts immobilized on clays

Clay-supported platinum catalysts were prepared by ion-exchange using catio nic clays. The immobilized platinum cations were reduced by applying liquid - or gas-phase reduction procedures. The catalysts obtained were examined b y X-ray diffractometry, and the results were compared with the diffractogra ms of the parent clays and that of a catalyst prepared by impregnation. The modifications in the diffractograms were used to estimate the fraction of metal migrated from the interlamellar space on the outer surface of the cla y lamellae. The reaction rates and selectivities obtained in the hydrogenat ion of cinnamaldehyde and crotonaldehyde over these catalysts supported our interpretation related to the position of the metal particles. (C) 2001 El sevier Science B.V. All rights reserved.