Catalytic Conversion of Chitin Biomass to 5-Hydroxymethylfurfural in Lithium Bromide Molten Salt Hydrates

5-Hydroxymethylfurfural (5-HMF) is one of the top valuableplatformchemicals that can be derived from biomass. Herein, a facile, mild,and efficient catalytic conversion method was developed to convertchitin biomass into 5-HMF in lithium bromide molten salt hydrates(LiBr MSHs) with boric acid (BA) as the catalyst. About 49.6% 5-HMFyield was obtained from glucosamine (GlcN) in 65 wt % LiBr MSHs at130 & DEG;C for 2 h with 800% BA addition. The system is applicableto other sugars, and the C2-substituted group of sugars played a significantrole in the 5-HMF yield. The 5-HMF yields were 81.3, 40.3, and 3.9%from fructose, glucose, and N-acetyl glucosamine(GlcNAc), respectively, under identical conditions. Combined withacid addition and Box-Behnken experiment designs, the directconversion of chitosan and chitin were achieved at 140 & DEG;C for5 h to produce 5-HMF with 21.6 and 15.3% yield. Ammonia quantitativeanalysis and NMR tests have been conducted, based on which a plausiblereaction pathway was proposed. The LiBr MSHs and the BA catalyst facilitatedthe hydrolysis, deacetylation, and ring-opening of chitin biomass.Especially, the catalyst BA played a key role in the formation of5-HMF, as it was found to promote dehydration at the last step. Thestudy put forward new avenues for chitin refinery to produce high-valuefuranic platform chemicals in cheap and green solvent systems.