Aviation biofuel range cycloalkane from renewables: Liquid-phase catalytic conversion of menthol on niobia-supported catalysts

摘要

Renewable terpene biomass has attracting interest for producing high energy density fuel, particularly cycloalkane in the range of jet fuels. In this contribution, catalytic conversion of menthol to p-menthane was systematically investigated. Noble metals (Pt, Pd and Ru) supported on a Lewis-BrOnsted acidic oxide (Nb2O5) were explored, considering the effects of reaction temperature and the balance between acid and metal sites. Catalysts kinetics were quite distinct, and Pd-based catalyst rendered the most active one. Yields of p-menthane of around 90% were determined over Pt and Pd catalysts, while it was only similar to 70% on Ru/Nb2O5, on which the formation of p-menthene was also observed. These results evidenced that the reaction proceeds as a cascade reaction at which acid-catalyzed menthol dehydration and metal-catalyzed cycloalkene hydrogenation lead to the aimed cycloalkane. Reaction temperature and the balance between acid and metal sites were shown to be the key aspects affecting catalyst performance.