甲壳素酰化改性的研究进展

Advances in acylation of chitin

甲壳素作为一种来源广泛的生物质材料,具有良好的生物相容性和抑菌性,可用于药物缓释、伤口包覆、组织植入、生物分离、重金属吸附等高附加值领域,但强烈的氢键作用使其不熔难溶,需经改性以促进其加工和应用。本文简要回顾了甲壳素酰化改性的发展历程,重点介绍均相条件下甲壳素的各种酰化方法,如在甲磺酸、氯化锂/二甲基乙酰胺、离子液体、三氟乙酸酐中进行反应,以及在非均相条件下提高酰化效率的各种方法,如优选催化剂、结构活化等,比较了各种方法的优缺点,并简述了甲壳素酰化产物的性能特点和应用。目前甲壳素非均相酰化工艺较成熟,已实现工业化,但仍有一定的局限性和缺点。最后展望了均相和非均相酰化可能的改进方向。

As one of the major bio-based materials,chitin shows excellent bio-compatibility and anti-bacterial properties and finds applications in many high value-added areas,such as drug release,wound healing,tissue implantation,bio-separation engineering and heavy metal absorption,etc. However,chitin is featured by extensive hydrogen bonding,making it unable to melt and difficult to be dissolved. Therefore,modification is important to facilitate the processing and application of chitin. In this article,the current state of acylation of chitin is reviewed by comparing different acylation methods under both homogeneous and heterogeneous conditions. Focus is on the homogeneous reactions in methanesulfonic acid,lithium chloride/dimethylacetamide,ionic liquids and trifluoroacetic anhydride. Methods for improving acylation efficiency under heterogeneous conditions are described,such as optimizing the catalyst and structural activation. The properties and applications of acylated chitin are also introduced. Although the acylation of chitin under heterogeneous conditions has been well developed, there are still some limits and shortcomings. This paper highlights the significant advantages of trifluoroacetic anhydride method under homogeneous conditions,as well as strategies for improving the heterogeneous acylation of chitin.