Liquefaction behavior of Western red cedar and Japanese beech in the ionic liquid 1-ethyl-3-methylimidazolium chloride

Western red cedar and Japanese beech are studied concerning their liquefaction behavior with an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]). Significant differences in liquefaction behavior were observed in terms of solubility and the lignin content of the insoluble residues. Thioacidolysis analysis of the residues confirmed that β-O-4 bonds in lignin were cleaved preferentially by the treatment with [C2mim][Cl]. The differences in liquefaction behavior can be explained by structural differences between softwood and hardwood lignins. Furthermore, gel permeation chromatography and GC-MS analyses revealed that cellulose and hemicelluloses were decomposed partly to monomeric sugars such as glucose, mannose, galactose, xylose, and arabinose.