Efficient conversion of glucosamine and N‐acetyl‐glucosamine to 5‐hydroxymethylfurfural and levulinic acid.

To valorize crustacean shells, an aquatic organism‐derived food waste, this study was conducted to synthesize 5‐hydroxymethylfurfural (5‐HMF) and levulinic acid (LA) from d‐glucosamine (GlcN) and N‐acetyl‐d‐glucosamine (GlcNAc) using a Lewis acid (ZrCl4) as a catalyst. The Box–Behnken statistical approach was used to optimize the reaction conditions and to analyze the reciprocal relationships between reaction parameters. In the GlcN conversion, the highest LA yield of 38.4% was obtained under a condition with 200 °C for 25 min with 0.35 M GlcN and 25 mol% catalyst/substrate. However, in GlcNAc conversion, the highest 5‐HMF yield of 9.75% was obtained at 175 °C for 20 min with 0.2 mol L−1 GlcNAc and 15 mol% catalyst/substrate. Under the same reaction conditions, a higher yield of LA was obtained from GlcN compared with GlcNAc. It seems that GlcN can be transformed into 5‐HMF and then further rehydrated to LA more readily than GlcNAc. These findings suggest that GlcN and GlcNAc derived from crustacean shells may be an accessible feedstock for the synthesis of valuable chemical compounds. [ABSTRACT FROM AUTHOR]