The role of spillover hydrogen in the hydrogenolysis of neopentane

In neopentane hydrogenolysis at 325-350 Deg over Pt supported on K-LTL zeolite, Pt clusters are capable of spilling over large quantities of H onto the support. The capacity of the support is limited, and is proportional to the d. of acidic hydroxyl groups. This correlation suggests that spilled-over hydrogen may be held at or near these acidic hydroxyl groups. Although there is a general trend of increasing hydrogenolysis TOF with the increasing amts. of spilled-over hydrogen, there is no causal relationship. Spillover sites do not form catalytic centers, not do they enhance hydrogenolysis activity. Differences in specific activity resulting from changes in the support acidity/basicity are due to modification of the electronic properties of the supported metal. These electronic changes, however, do not alter the reaction selectivity.