Activity and structure of [formula omitted] catalysts for toluene steam dealkylation

Abstract

The catalytic activity of Rh Cr 2O 3 in toluene steam dealkylation has been correlated with catalyst properties and structure. The maximum exploitation of the precious metal was found for a concentration of rhodium not higher than ca. 0.8 wt%. At higher Rh loading, increasing amounts of the precursor Rh 3+ ions probably diffuse within the crystal lattice of the support, during the preparation of the catalyst, and in such a form they are not reduced to active Rh 0. The progressive loss observed in reaction selectivity is likely to be due to the change conferred by such Rh 3+ ions on the properties of the chromia.