Mild and Selective Hydrogenation of Furfural and Its Derivatives to Tetrahydrofurfuryl Compounds Catalyzed by Aluminum Oxide-supported Nickel Carbide Nanoparticles
Taiki Kawakami, Sho Yamaguchi, Satoshi Suganuma, Kiyotaka Nakajima, Takato Mitsudome, Tomoo Mizugaki
Abstract
The hydrogenation of furfural (FUR), a representative lignocellulosic biomass-derived furanic compound, is a promising method for synthesizing tetrahydrofurfuryl alcohol (THFA), which is used as a solvent and pharmaceutical intermediate. Significant efforts have been made to develop non-precious metal catalysts for the hydrogenation of FUR to THFA; however, these systems typically require harsh reaction conditions, such as high hydrogen pressure. In this study, we found that aluminum oxide-supported nickel carbide nanoparticles (Ni 3 C NPs/Al 2 O 3 ) function as a highly active non-precious metal catalyst for the selective hydrogenation of FUR and its derivatives into the corresponding tetrahydrofuran derivatives with high yields. Notably, Ni 3 C NPs/Al 2 O 3 enables the hydrogenation of FUR to THFA with over 90% yield even at 0.1 MPa of H 2 . The Ni 3 C NPs/Al 2 O 3 catalyst also demonstrated effectiveness in gram–scale reactions. Control experiments and structural characterizations revealed its unique catalytic properties: polar hydrogen species formed on the Ni 3 C NPs surface efficiently reduce the aldehyde moiety of FUR, while cooperative effect at the Ni 3 C NPs–Al 2 O 3 interface is essential to promoting the hydrogenation of a furan ring. These properties significantly enhance the catalytic performance of Ni 3 C NPs/Al 2 O 3 .