Synthesis of a 5-(Hydroxymethyl)furfural-based resin and its use as heterogeneuos catalyst

The search for new chemicals and materials derived from biomass has gained more attention in the last decades, considering the increased search for the substitution of fossil-based chemicals. As far as green chemistry is concerned, it is worth mentioning the recent technological improvements in the field of organic synthesis with the adoption of enabling technologies such as continuous flow chemistry. Compared to the traditional way to do organic synthesis using round-bottomed flasks, the use of flow chemistry brings several benefits including ease scale up, multistep synthesis, and safer reactions. Bearing this in mind, this work aimed at the use of 5-(Hydroxymethyl)furfural (5-HMF) as starting material for the synthesis of new organic building blocks and materials. Firstly, 5-HMF was converted to 2,5-di(hydroxymethyl)furan (DHMF) employing NaBH4 as reducing agent. Combining DHMF and maleic anhydride for a Diels-Alder reaction, an unexpected polymerization reaction occurred, giving rise to an insoluble and amorphous material. This solid was characterized by several techniques such as 13 C NMR, FTIR, and DSC. After measuring the pH for this solid in an aqueous medium (pH 3), this material was evaluated as a heterogeneous acid catalyst. Thus, the dehydration of D-Fructose into 5-HMF was carried out in a continuous flow regime using a fixed-bed reactor and yields up to 70% were obtained.