Reactivity of electron donor-acceptor complexes. Part 9.—Isomerization of butene

Abstract

The isomerization of butene was studied over various electron donor-acceptor (EDA) complexes for which the behaviour of hydrogen had been examined. The relative catalytic activity of the EDA complexes for cis-2-butene isomerization to 1-butene and trans-2-butene was closely connected with that for the H₂—D₂ exchange reaction, the activities for both reactions depending upon the electron affinity of the acceptor molecules. The activity of the EDA complexes of sodium has a maximum in the region of 0–0.6 eV for the electron affinity of the acceptor molecules and is small or negligible for either stronger or weaker acceptor molecules. The EDA complexes of magnesium, on the other hand, showed a maximum in the region of 1.2 and 1.6 eV for the electron affinity. Accordingly, a weaker electron donor gives optimal activity with a stronger electron acceptor.

The cis-trans isomerization of butene was also studied over various EDA complexes of aromatic compounds with SbCl₅, an electron acceptor; an optimal region of ionization potential (about 7.0 eV) of electron donors was demonstrated.