A new approach to the etherification of bio-based furanic compouds via continuos flow.

The main goal of Biorefinery is the transition from a fossil-fuel-based model to a more sustainable system focused on renewable raw materials, in line with circular economy principles.1,2 In this context, the so-called Bio-Based Platform Chemicals play an important role. Among them, 5-hydroxymethylfurfural (HMF) and 2,5-bis(hydroxymethyl)furan (BHMF) - achieved by HMF hydrogenation - are two of the most studied representatives. Etherification of these compounds with different alcohols yields 5-(alkoxymethyl)furfurals (AMFs) and 2,5-bis(alkoxymethyl) furans (BAMFs) respectively, both demonstrating potential application as fuel additives.3 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.4 From this premises, the present talk will focus on the etherification of HMF and BHMF using a commercially available ion exchange resin - Purolite CT275DR, using a continuous flow apparatus. The reaction conditions were optimized by evaluating several key parameters, including catalyst type and quantity, reaction media, temperature, and flow rate for the etherification of BHMF with ethanol and then extended to achieve a library of BAMFs. HMF self-etherification to form OBMF was carried out employing both heterogeneous (CT275DR) and homogeneous acid (methanesulfonic acid - MSA) catalysts using dimethyl carbonate (DMC) as green solvent, with the latter being the most efficient. Lastly, green metrics were calculated for the optimized etherification of BHMF with ethanol and the values were compared to previously published procedures.