Isomerization of 5-vinyl-2-norbornene using sodium-coated catalysts

Abstract

Various sodium-coated metal oxide catalysts were prepared using readily available supporting materials such as neutral γ-Al2O 3 (neutral alumina, N-Al2O3) basic γ-Al2O3 (basic alumina, B-Al2O 3), SiO2, MgO, and TiO2, and their catalytic activities were evaluated for the isomerization of 5-vinyl-2-norbornene (VNB) to 5-ethylidene-2-norbornene (ENB). Of various sodium-coated catalysts, Na/N-Al2O3 and Na/B-Al2O3 showed extremely high activities, resulting in quantitative conversion of VNB. Catalyst characterization and isomerization results clearly demonstrated that the presence of both strong basic sites (pKBH ≥ 27) and one-electron donor sites on the Na/Al2O3 is prerequisite for the isomerization of VNB to take place.