Abstract: The dissolution of sawdust in alkaline solvent system NaOH-thiourea-H2O was studied, and the separation of the lignocellulosic ingredients combined with acid precipitation method proposed. The results showed that the main residue after the treatment in alkali solvent was lignin, and the filtrate from acid precipitation of the liquor cellulose. The optimal dissolution conditions were determined by single-factor experiments as follows: the ratio of liquid to solid 30 mL/g, dissolution temperature 70℃, and dissolution time 2.0 h. FT-IR, SEM, XRD and NMR were employed to identify the structure of separated components, the dissolution rate could achieve 60.3%, and cellulose yield after acid precipitation about 39.2%.

Key words: lignocellulose, alkali system, thiourea, dissolution, component separation

摘要： 实验研究了NaOH-硫脲-H2O组成的碱溶剂体系对木屑的溶解规律，并结合酸沉方法分离木质纤维素的3种主要成分. 结果表明，碱溶剂处理后剩余的固体物质为木质素，滤液经酸沉后沉淀的主要成分是纤维素，半纤维素全部水解. 单因素实验确定最佳溶解条件为：液固比30 mL/g、溶解温度70℃、溶解时间2.0 h，在此条件下，木屑的溶解率达60.3%，酸沉后纤维素收率为39.2%. 对溶解及酸沉后剩余固体物质进行了结构分析，证明分离方法的可行性.

关键词: 木质纤维素, 碱体系, 硫脲, 溶解, 组分分离