Furfural hydrogenation into tetrahydrofurfuryl alcohol under ambient conditions: Role of Ni-supported catalysts and hydrogen source

Herein hydrogenation of biomass-derived furfural (FAL) catalyzed by Ni-supported catalysts and NaBH4 into tetrahydrofurfuryl alcohol (THFA) demonstrated in aqueous media under ambient reaction conditions. The activity of various Ni-supported catalysts (Ni/active carbon (Ni/AC); Ni/carbon black (Ni/CB); Ni/bone char (Ni/BC); Ni/C (derived from Ni-MOF)) compared for FAL hydrogenation. Ni/AC exhibited a high activity towards FAL hydrogenation into THFA (99% yield) compared to all other Ni-supported catalysts tested in this study. The results showed that hydrophobic nature of the AC support in Ni/AC, higher specific BET surface area, and smaller Ni particle size enhance the FAL hydrogenation proficiency towards THFA in aqueous media under milder reaction conditions. The FAL is efficiently hydrogenated with NaBH4 (hydrogen source). On the contrary, FAL is not hydrogenated in pure H2, suggesting a crucial role of NaBH4 in FAL hydrogenation. For the first time, the role of NaBH4 is investigated in detail for the hydrogenation of biomass-derived furans. The interaction of NaBO2 produced from NaBH4 with furfuryl alcohol (FOL) enhances the adsorption of the furan ring of FOL on the Ni surface via parallel geometry, resulting in efficient furan ring hydrogenation of FOL into THFA.