Isomerization of 5-Vinyl-2-norbornene Using Sodium-coated Catalysts

摘要

Various sodium-coated metal oxide catalysts were prepared using readily available supporting materials such as neutral ャ-Al₂O₃ (neutral alumina, N-Al₂O₃) basic ャ-Al₂O₃ (basic alumina, B-Al₂O₃), 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 (pK_BH ∶ 27) and one-electron donor sites on the Na/Al₂O₃ is prerequisite for the isomerization of VNB to take place.