Etherification of 5-hydroxymethylfurfural using a heteropolyacid supported on a silica matrix

In this work, Preyssler-type heteropolyacids and their silica-included counterparts were employed in the etherification reaction of HMF and n-BuOH. Materials were synthesized with a Preyssler acid load of 12.5% w/w using the sol-gel technique, which improved surface areas and modulated their acid strength. Prepared materials were used as heterogeneous solid acid catalysts in the selective etherification of 5-hydroxymethylfurfural (HMF) to 5-butoxymethylfurfural (5BMF). The high catalytic performance of the bulk Preyssler acids is related to their high acid strength, while selectivity related to the decrease in acidity by the inclusion effects. Different reaction parameters were optimized, with PWMo(12.5%)@SiO2 exhibited the highest catalytic activity with 89% of HMF conversion and 73% of 5BMF selectivity. The catalyst is reusable up to five cycles without noticeable decrease in selectivity.