Influence of sodium on the physico-chemical and catalytic properties of magnesium oxide

Abstract

Physico-chemical and catalytic properties of two series of catalysts comprising magnesia and sodium were determined. The first (I) series of catalysts was prepared by doping magnesia with varying amounts of NaOH. The second (II) series of catalysts was obtained by evaporating metallic sodium onto MgO preparations precalcined at different temperatures.

The concentration and strengths of basic and acid sites, as well as the amounts of one-electron donor and one-electron acceptor sites, were measured, and the specific surface areas of the catalysts determined. Catalytic activity in isomerization of pent-1-ene, trans-pent-2-ene and the conversion of cumene was studied. It was concluded that the (II) series of catalysts displayed remarkably strong basic and one-electron donor properties. Also, it was proved that basic sites coexist on the surfaces of catalysts with the one-electron donor sites. Catalytic activity in alkene isomerization and cumene dehydrogenation was unambiguously associated with the presence of well-defined surface active sites.