Reaction behavior of milled wood lignin in an ionic liquid, 1-ethyl-3-methylimidazolium chloride

• Published in: Journal of wood science Vol. 61; no. 3; pp. 285 - 291
• Main Authors: Ogawa, Shintaro, Miyafuji, Hisashi
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.06.2015; Springer Nature B.V
• Subjects: Beech; Biomedical and Life Sciences; Cedar; Characterization and Evaluation of Materials; Chlorine; Depolymerization; Ionic liquids; Ions; Life Sciences; Lignin; Low molecular weights; Materials Science; Molecular weight; Original Article; Vanillin; Wood Science & Technology; Milled wood lignin; 1-ethyl-3-methylimidazolium chloride; Reaction behavior; Ionic liquid; Heating method
• ISSN: 1435-0211; 1611-4663
• DOI: 10.1007/s10086-015-1461-3

We investigated the reaction behavior of milled wood lignin (MWL) obtained from Japanese cedar ( Cryptomeria japonica ) and Japanese beech ( Fagus crenata ) in an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]). This solvent can liquefy wood. The sample was treated with [C2mim][Cl] at 120 °C using an oil bath or microwave irradiation. MWL easily dissolved in [C2mim][Cl]. Although solubilized, MWL was slightly depolymerized and it retained its high molecular weight after 96 h of treatment. Only small amounts of low molecular weight compounds such as vanillin, coniferylaldehyde, syringaldehyde and sinapylaldehyde were produced. As the treatment time was extended the chlorine from [C2mim][Cl] reacted with the MWL. These results indicate that MWL is stable in [C2mim][Cl] although limited depolymerization and modification by [C2mim][Cl] occurred.