The catalytic cracking of cumene studied by reversed-flow gas chromatography

Abstract

The new technique of reversed-flow gas chromatography has been applied to the catalytic cracking of cumene over LaY and HY zeolites. The delta mechanism of Campbell and Wojciechowski (J. Catal., 1971, 20, 217) was chosen as the basis for the derivation of the rate equation. Two limiting cases of this equation arise when one or two steps in the proposed mechanism are rate-controlling. With the aid of the equations derived, rate constants and activation parameters for the dealkylation reaction of cumene have been determined.

For the LaY catalyst the formation of propene is governed by one rate-controlling step, whilst in the formation of benzene two such steps are involved, the second of which is the slow desorption of the product. For the HY catalyst the desorption of benzene appears to be the only rate-controlling step.