Influence of the location of Rh(0) particles within MCM-41 materials on the selectivity of hydrogenation reactions.
Résumé
Rh0-MCM-41 solids have been prepared by the alkaline hydrolysis of silicon precursors in the presence of cetyltrimethylammonium bromide (CTABr) and Rh(III) salts or 2-3 nm Rh0 colloids. All the resulting solids were used in the catalytic hydrogenation of xylenes and lead to lower selectivities in cis dimethylcyclohexanes than Rh0 colloids tested either under biphasic conditions or deposited onto silica gel. Such variations have been attributed to the insertion of the Rh precursors into the MCM-41 synthesis gel.