Determination of the Active Site and Mechanism for Alkene Isomerization in Cun Exchanged Y-Type Zeolite

Abstract

Reactions of CD2[double bond, length as m-dash]CH—CH3, but-1-ene and 3,3-dimethylbut-1-ene have been studied over a Y-type zeolite containing ∼4 CuII per unit cell. Kinetic induction periods, associated with the generation of active sites by CuII reduction, were only observed for the deuterium redistribution reactions of CD2[double bond, length as m-dash]CH—CH3. Nevertheless, arguments are presented to show that such generation of active sites is central to alkene isomerization reactions over CuII exchanged X- and Y-type zeolites. The mechanism of alkene isomerization is shown to require carbonium ions, generated from protons produced following CuII reduction by the alkene.