Cellulose dissolution and conversion into 5-hydroxymethylfurfural in mixed molten salt hydrate

Molten salt hydrate (MSH) is a good solvent for cellulose dissolution and an effective catalyst for cellulose conversion. In this work, a series of MSH was evaluated in terms of cellulose dissolvability, regeneration performance, and catalytic activity in cellulose conversion into 5-hydroxymethylfurfural (HMF). ZnBr 2 ·3H 2 O–LiCl·3H 2 O showed good performance on cellulose dissolution and conversion. The effects of ZnBr 2 ·3H 2 O concentration, reaction temperature, and time on cellulose conversion into HMF in ZnBr 2 ·3H 2 O–LiCl·3H 2 O were optimized, and 48.7% HMF yield was reached at 60 wt.% ZnBr 2 ·3H 2 O. The species of ZnBr 2 ·3H 2 O–LiCl·3H 2 O were analyzed, and the function of species concentration was correlated with the product yield from the conversion of fructose. It was found that Br − and H + were the active species for fructose dehydration into HMF. ZnBr 3 − and H + catalyzed the conversion of fructose into furfural, which competed with the production of HMF. The reaction mechanism was proposed to understand the cooperate of species in MSH for cellulose conversion.