木质素是自然界中最丰富的可再生芳香族聚合物,可制备生物燃料和高附加值化学品。在以石油为基础的现代能源与化工行业中,木质素作为替代原料展现出良好的应用前景。要实现木质素的利用,必须首先充分了解木质素的组成与结构特征。然而,由于木质素来源的多样化和结构的复杂性给了解木质素的组成结构带来巨大的困难。本文以揭示木质素的化学组成为出发点,分析比较了应用于木质素结构研究的分离提取、转化以及分析测试等方法与技术,重点阐述了木质素结构研究最新进展,包括木质素的组成单体及其连接方式、生物合成过程、模型化合物的反应和木质化理论体系等,概述了木质素及其衍生物在聚合物材料、树脂、炭纤维、活性炭和高附加值化学品制备等领域的应用,展望了木质素的结构研究与应用的发展方向并提出了需要解决的相关难点问题。
As the most abundant natural renewable aromatic polymers, lignins can be used to produce bio- fuels and value-added chemicals. Lignins attract more and more attention in energy and chemical industrials, and have the potential to substitute petroleum as raw materials to some extent. To realize the application of lignins, the chemical composition and structural characteristics should be fully understood. However, the ubiquitous crosslinks among lignins, cellulose and hemicelluloses are complex, resulting in the incomplete separation of lignin from biomass. In addition, diverse sources and complex structures embarrass the development of investigation and application. With revealing the chemical compositions of lignins as the starting point, methodologies and technologies, such as pretreatment, separation, transformation and analysis, for the structural investigation of lignins are compared, and the up-to-date advances, including monolignols and linkages of lignins, biosynthetic processes, the reactions of model compounds and lignification theories are importantly reviewed. The applications of lignins and their derivatives in the fields of polymer blends, resins, carbon fiber, activated carbon and other chemicals along with related difficult problems are pointed out.