ESTIMATION OF HYDROGEN TRANSFER RATES OVER ZEOLITE CATALYSTS

A kinetic model has been developed to describe the product distribution of the reaction of cyclohexene on acidic zeolite catalysts. The model was used to estimate the rate constants for hydrogen transfer, isomerization, oligomerization, cracking and coking for various zeolite catalysts. Over Y-zeolites, the selectivity toward hydrogen transfer increases by a factor of 1.7 as the number of Al atoms per unit cell increases from 4.6 to 33.4. The selectivity toward hydrogen transfer can be correlated with the fraction of paired Al sites in the zeolite as estimated by a statistical calculation. Over zeolites of comparable silica to alumina ratio, the ratio of isomerization selectivity to hydrogen transfer selectivity was the highest for H-ZSM-5, followed by H-beta and REUSY. © 1990.