Production of 5-hydroxymethylfurfural from agarose by using a solid acid catalyst in dimethyl sulfoxide

In this study, an effective method for 5-HMF production from agarose, a biomass material derived from redalgae, is proposed. 5-HMF was produced from the decomposition of agarose by the catalytic action of a solid acid, Amberlyst 36, in dimethyl sulfoxide (DMSO), which is a polar aprotic solvent apt for providing a micro-aqueous environment. The moisture content in DMSO was found to be the governing factor for 5-HMF production, with an optimum level of 7.2% at which the 5-HMF yield was 62%, the highest level ever observed in the production of 5-HMF from agarose. DMSO was also found to protect 5-HMF, once produced, from rehydration in the present system. It was demonstrated that Amberlyst 36 could be repeatedly used in a packed-bed reactor, which was the prime objective of using a solid acid instead of a liquid acid as catalyst.