对麦草碱木素在强碱性离子液体［Bmim］［OH］溶解过程中木质素的结构变化进 行了解析，并对溶解机理进行了探讨． 利用微波加热辅助溶解，实验条件如下: 微波功率 500 W，温度 90 ℃，反应时间 30 min，固液比 1∶ 10． 通过傅里叶变换红外光谱( FT-IR) 、凝 胶渗透色谱( GPC) 、元素分析、二维异质单量子相干核磁共振( 2D HSQC NMR) 、瞬时高温 热解装置 － 气相色谱 － 质谱联用( Py-GC-MS) 等方法进行分析和表征． 研究结果表明: 碱 木素在［Bmim］［OH］离子液体溶解过程中其芳香环结构保持稳定，主要发生了侧链取代 或单元连接间含氧基团的脱除，溶解后再生的木质素相对分子质量轻微下降，分子量分布 更加均匀; 同时，再生木质素的不饱和度增大，这是由于溶解过程中发生了脱水反应． 二维 核磁共振光谱与 Py-GC-MS 分析表明，在强碱性离子液体体系中木质素的溶解过程以大 分子中 β-O-4'键的断裂最为明显，β-β、β-5 次之，S /G 比例明显降低． 文中成果为碱木素高 值化应用的相关理论和产品开发提供了基础数据和技术方向．

This paper deals with the structure variation of wheat straw alkali lignin in alkaline ionic liquid ［Bmim］ ［OH］and the dissolution mechanism of alkali lignin． The dissolution was assisted by microwave heating with a microwave power of 500 W，a temperature of 90 ℃，a reaction period of 30 min and a solid-to-liquid ratio of 1∶10． By using ［Bmim］ ［OH］ionic liquid as a solvent，the lignin dissolution process was characterized and analyzed by means of FT-IR，GPC，elemental analysis，2D HSQC NMR and Py-GC-MS． The results indicate that，during the dissolution of alkali lignin in ionic liquid ［Bmim］［OH］，the aromatic rings remains stable and there mainly occurs the substitution of the side chain or the removal of oxygen-containing groups; and that，after the dissolution，the relative molecular mass of the regenerated lignin slightly decreases，the molecular mass distribution become more uniform and the degree of unsaturation increases due to the dehydration reaction during the dissolution processes． Moreover，2D HSQC NMR and Py-GC-MS results prove that there mainly happens the cleavage of β-O-4' aryl ether linkages during the dissolution of lignin in strongly basic ionic liquid system，followed by β-β and β-5 structures，and the S /G ratio remarkably decreases． This research provides basic data and an approach to the development of relevant theories and the application of high-value alkali lignin