HYDROGENOLYSIS OF NEOPENTANE AND N-PENTANE OVER A RH-GAMMA-AL2O3 CATALYST

A detailed study was made of the hydrogenolysis of two pentane isomers on a well-characterized Rh γ-Al2O3 catalyst. The neopentane cracking takes place sequentially by succesively breaking off methane molecules. Turnover numbers, rate constants, and activation energies were determined for all the four consecutive steps. The n-pentane hydrogenolysis simultaneously follows a major path to propane and ethane and a minor one to n-butane and methane. The kinetic parameters were determined for both paths. The reaction orders for both hydrogenolysis reactions were 1.0 for the hydrocarbon and -1.5 for hydrogen. The course of the catalytic reactions is in agreement with the presence of surface intermediates which make three bonds to two adjoining surface sites. The predominant formation of propane and ethane from n-pentane on well-dispersed, supported Rh is associated with the predominant formation of one such intermediate. © 1979.