Support-induced compensation effects in H/D exchange of cyclopentane

The exchange of hydrogen for deuterium (H/D exchange) in cyclopentane was measured for Pt catalysts with supports of various acidity. With an earlier developed Monte-Carlo model the contributions of the various possible intermediates in the H/D exchange can directly be measured. It was shown that the activity and the selectivity in the H/D exchange over the supported Pt catalysts strongly depend on the support acid/base properties. The activities of the various catalysts show a compensation effect. The compensation effect can directly be correlated to the contribution of the various exchange mechanisms, which proceed via different intermediates. The contribution of each intermediate depends on the electronic properties of the Pt particles, which in turn depend on the support acidity. This shows that the compensation effect is caused by support-induced changes in the adsorption modes of cyclopentane.