Electrochemical study of the reactivity of furfural and 5-hydroxymethylfurfural with aliphatic primary (di)amines

Abstract

Furfural (FF) and 5-hydroxymethylfurfural (HMF) are important and prospective renewable sources for chemical, fuel, material or pharmaceutical industry, the furfurylamines being the desired precursors. In this contribution new effects related to the reactivity of FF and HMF with various aliphatic primary (di)amines were observed using an electrochemical approach in water solutions. Following an initial investigation of electroreduction, the course of condensation reactions in basic buffers under various stoichiometric conditions was electrochemically monitored. Using five aliphatic amines and two (α,β- and α,ω-) diamines, a variety of products (mainly Schiff-bases) was identified. As a pilot study for “one-pot” reductive amination, the mixture of FF and n-PrNH2 was electrochemically reduced in basic buffers. The vicinal diamine (analogue of a pinacol) was the main product, together with the expected furfurylamine.