Step by step modeling of superbasic catalysts of the EDA complex type

A range of catalysts was synthesized; these catalysts contained species analogous to the structures appearing during the various elementary steps in the hydrogenation of alkenes over catalysts of extremely strong one-electron donor centers. The primary catalytic system, gamma-Al2O3-metallic potassium, was modified by naphthalene, anthracene, and perylene vapors to form surface electron donor-acceptor (EDA) complexes. The specific EDA complexes were also prepared by the immobilization of potassium naphthenide on a gamma-Al2O3 surface in amounts relative to the number of surface hydroxyls. The investigated catalysts were tested in the isomerization of 1-pentene and 1-hexene and in the hydrogenation of ethene and propene. The catalytic importance of ion radical species of alkenes formed during their isomerization and hydrogenation over superbasic systems was demonstrated. (C) 1997 Academic Press.