title: Catalytic Depolymerization of Chitin with Retention of N-Acetyl Group.
abstract: Chitin, 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.
authors.affiliation: Institute for Catalysis, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan.
authors.forename: Mizuho
authors.initials: M
authors.lastname: Yabushita
authors.affiliation: Institute for Catalysis, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan. kobayashi.hi@cat.hokudai.ac.jp.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Kuroki
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Ito
authors.affiliation: Institute for Catalysis, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan. fukuoka@cat.hokudai.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukuoka
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry*; D002384:Catalysis; D002686:Chitin / Q000737:chemistry*; D006868:Hydrolysis; D058105:Polymerization; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D013464:Sulfuric Acids; D002686:Chitin; C033158:sulfuric acid; D000117:Acetylglucosamine
keywords: biomass; catalysis; chitin; hydrolysis; mechanochemistry