Monomolecular Skeletal Isomerization of 1-Butene over Ferrierite and HPM-1 Zeolites

Abstract

Catalysis is always an elegant way that chemists use to drive a reaction to the desired product in fields as diverse as petrochemistry, fine chemistry, and drug production. Apart from its technological relevance, 1-butene skeletal isomerization catalyzed by zeolite acids is of considerable scientific interest, because the exact reaction pathway remains elusive. Here we present direct evidence that even the initial isobutene formation over H-ferrierite, the best-known isomerization catalyst, is monomolecular in nature. We also report that H-HPM-1, a medium-pore high-silica zeolite, outperforms H-ferrierite in selectively forming isobutene. This new catalyst displays a high activity and selectivity since the onset of the reaction, together with an excellent resistance to deactivation, because of its anomalously weak acidity and ability to effectively isolate reactant molecules from one another.