磷酸丙酮法木质纤维素预处理中木质素的分离与表征

在木质纤维素制取乙醇过程中，合理高效地分离出木质素并加以利用，可以提升纤维乙醇整体工艺的经济性。 以杨木粉为原料，从木质素产率和改性程度的角度出发，分析对比了3种预处理方法所提取的木质素。 结果表明，磷酸丙酮法所得木质素产率达到15%~25%，碱法蒸煮法和有机溶剂所得木质素仅占到9.58%和13.47%。 红外吸收光谱结果表明，磷酸丙酮木质素在1608、1507和1463 cm-1等处具有相对最强的吸收信号，在1650 cm-1处也有共轭羰基吸收峰，因此磷酸丙酮木质素的改性程度相对较小，核磁共振氢谱表征也同时验证了这一结果，这种木质素适于进一步的开发利用。 低压常温下的磷酸丙酮预处理方法可以有效提升纤维乙醇工艺的经济性。

Separation and Characterization of Lignin in Phosphoric Acid-acetone Pretreating Process

In lignocellulosic ethanol production process, utilization of separated lignins can improve the economy of cellulosic ethanol technology. In this article using poplar power as feedstock, lignin extracted from three methods were analyzed and compared from the perspective of lignin yield and molecule modification degree. Phosphoric acid-acetone lignin is characterized by its high yield of 15%~25%. Alkaline cooking and organic solvent method can only reach 9.58% and 13.47%. By FT-IR characterization, it is confirmed that phosphoric acid-acetone lignin has the biggest absorption signal at 1608 cm-1, 1507 cm-1 and 1463 cm-1, and its conjugated carbonyl absorption peak also exists at 1650 cm-1. This result indicate that it has the lowest modification. 1H NMR analysis also supports this conclusion. Phosphoric acid-acetone pretreatment can raise the economy of cellulosic ethanol process under lower temperature and normal pressure.