Metal Catalyst and Hydrogen Gas-Free Selective Reduction of Biomass-Derived Substituted Furfuraldehyde to Alkyl Furan as a Key Biofuel Additive

Abstract

A metal catalyst and a hydrogen gas-free approach has been developed for selective reduction of aldehyde to an alkyl group of different substituted furan compounds. In this process, hydrazine hydrate under basic conditions at reflux temperature selectively participated in the reduction of the aldehyde moiety to the corresponding alkyl group of highly reactive furan compounds in a selective manner. The developed protocol was applied for selective and scalable reduction of 5-hydroxymethylfurfural (5-HMF) up to 250 g to 5-methylfurfuryl alcohol (MFA) in a 70% yield. Under the same process, furfuraldehyde was also tested in a 250 g reaction for 2-methylfuran (MF) synthesis in a highly selective manner and the product was distilled out from a single-pot reaction with gas chromatography (GC) purity ≥90%. The scope of the process was further extended for different substituted furfuraldehydes successfully. In addition, the protocol is found to be efficient for scalable production and easy separation of the product.