Etherification of Bio‐Based Furanic Compounds via Continuous Flow

Abstract The ultimate goal of biorefinery is to move away from a fossil‐based industry aiming to a more sustainable one centered on the use of renewable feedstocks. It is well known that numerous bio‐based platform chemicals can be obtained from biomass. Among them, 5‐hydroxymethylfurfural (HMF) and 2,5‐bis(hydroxymethyl)furan (FDCA) – achieved by HMF hydrogenation – are two of the most studied representatives. The etherification of these molecules with different alcohols yields 5‐(alkoxymethyl)furfurals (AMFs) and 2,5‐bis(alkoxymethyl) furans (BAMFs) respectively, both demonstrating potential application as fuel additives. In addition, HMF, when subjected to self‐etherification, leads to 5,5′‐[oxybis(methylene)]bis‐2‐furfural (OBMF), another bio‐based monomer of growing interest. In this work, a comprehensive investigation on the etherification of HMF and 2,‐5‐bis(hydroxymethyl)furan (BHMF) promoted by a commercially available ion exchange resin – Purolite CT275DR – is conducted using a continuous flow apparatus. The reaction conditions are optimized for the etherification of BHMF with ethanol and then extended to achieve a library of BAMFs. In addition, HMF etherification and self‐etherification are studied. HMF self‐etherification to form OBMF is conducted using dimethyl carbonate in the presence of both heterogeneous and homogeneous acid catalysts. Finally green metrics are calculated for the etherification of BHMF with ethanol and the values are compared to previously published procedures.