Catalytic Depolymerization of Chitin with Retention of N‐Acetyl Group

• DOI: 10.1002/cssc.201501224
• Publication Date: 2015-11-05T11:46:56Z
• Authors: Mizuho Yabushita; Hirokazu Kobayashi; Kyoichi Kuroki; Shogo Ito; Atsushi Fukuoka
• Keywords: biomass; catalysis; Hydrolysis; Chitin; Sulfuric Acids; chitin; 431; 01 natural sciences; Catalysis; Acetylglucosamine; Polymerization; 0104 chemical sciences; hydrolysis; mechanochemistry

AbstractChitin, a polymer of N‐acetylglucosamine units with β‐1,4‐glycosidic linkages, is the most abundant marine biomass. Chitin monomers containing N‐acetyl groups are useful precursors to various fine chemicals and medicines. However, the selective conversion of robust chitin to N‐acetylated monomers currently requires a large excess of acid or a long reaction time, which limits its application. We demonstrate a fast catalytic transformation of chitin to monomers with retention of N‐acetyl groups by combining mechanochemistry and homogeneous catalysis. Mechanical‐force‐assisted depolymerization of chitin with a catalytic amount of H2SO4 gave soluble short‐chain oligomers. Subsequent hydrolysis of the ball‐milled sample provided N‐acetylglucosamine in 53 % yield, and methanolysis afforded 1‐O‐methyl‐N‐acetylglucosamine in yields of up to 70 %. Our process can greatly reduce the use of acid compared to the conventional process.