Methods for producing chitin oligomer, N-acetylglucosamine, and 1-O-alkyl-N-acetylglucosamine
The present invention relates to a method of producing a chitin oligomer, including subjecting chitin-containing biomass to partial hydrolysis while pulverizing the chitin-containing biomass with a pulverization apparatus in the co-presence of water and an acid catalyst selected from phosphoric acid, nitrous acid, and an organic acid (Method 1); a method of producing N-acetylglucosamine, including hydrolyzing a chitin oligomer obtained by the Method 1 by adding water thereto, followed by heating (Method 2); and a method of producing a 1-O-alkyl-N-acetylglucosamine, including alcoholyzing a chitin oligomer by adding an alcohol thereto (Method 3).
1. A method of producing a chitin oligomer, including subjecting chitin-containing biomass to partial hydrolysis while pulverizing the chitin-containing biomass with a pulverization apparatus in the co-presence of water and an acid catalyst selected from phosphoric acid, nitrous acid, and an organic acid,
wherein a ratio (S/C) of a number of moles (S) of an N-acetylglucosamine unit (C 8 H 13 NO 5 ) in chitin to a number of moles (C) of the acid catalyst is from 1 to 10.
2. The method of producing a chitin oligomer according to claim 1 , wherein the acid catalyst is phosphoric acid.
3. The method of producing a chitin oligomer according to claim 1 , wherein the pulverizing includes pulverizing the chitin-containing biomass, which is impregnated with the acid catalyst in advance, in the presence of water.
4. The method of producing a chitin oligomer according to claim 3 , wherein the method includes mixing a solvent having dissolved therein the acid catalyst with the chitin-containing biomass, then removing the solvent to impregnate the chitin-containing biomass with the acid catalyst, and pulverizing the resultant chitin-containing biomass impregnated with the acid catalyst in the presence of water.
5. The method of producing a chitin oligomer according to claim 4 , wherein the solvent is free of modifying the chitin-containing biomass, free of inhibiting acid catalyst activity, and capable of being removed by heating or distillation.
6. The method of producing a chitin oligomer according to claim 5 , wherein the solvent is selected from water, diethyl ether, hexane, and benzene.
7. The method of producing a chitin oligomer according to claim 1 , wherein the pulverization apparatus is a ball mill.
8. The method of producing a chitin oligomer according to claim 7 , wherein the ball mill is a planetary ball mill or a tumbling ball mill.
9. The method of producing a chitin oligomer according to claim 1 , wherein the chitin-containing biomass impregnated with the acid catalyst and subjected to the partial hydrolysis has 1 mass % to 3 mass % of water physisorbed thereto.
10. The method of producing a chitin oligomer according to claim 1 , wherein the ratio (S/C) is from 1 to 2.
11. A method of producing N-acetylglucosamine, including hydrolyzing a chitin oligomer obtained by the method of claim 1 by adding water thereto, followed by heating.
12. The method of producing N-acetylglucosamine according to claim 11 , wherein the heating is performed at a temperature of from 100° C. to 260° C.
13. A method of producing a 1-O-alkyl-N-acetylglucosamine, including alcoholyzing a chitin oligomer obtained by the method of claim 1 by adding an alcohol thereto.
14. The method of producing a 1-O-alkyl-N-acetylglucosamine according to claim 13 , wherein the alcohol is a monohydric alcohol.
15. The method of producing a 1-O-alkyl-N-acetylglucosamine according to claim 13 , wherein the alcohol is methanol, and wherein the 1-O-alkyl-N-acetylglucosamine is 1-O-methyl-N-acetylglucosamine.
16. The method of producing a 1-O-alkyl-N-acetylglucosamine according to claim 13 , wherein the alcoholysis is performed under heating at a temperature of from 120° C. to 280° C.