木质纤维素热解是一种高效生物质利用途径,其衍生产物左旋葡聚糖(LGA)是纤维素热解产物中最主要的初级产物,其产率可高达80%,将LGA高效转化为其他平台化学品可实现其高值化利用。首先综述了纤维素热解制备LGA的研究进展,对比反应器类型和反应条件对LGA产率的影响,生物质预处理工艺将进一步提升工业化规模制备LGA。然后概述了LGA在不同条件下转化为左旋葡萄糖酮、葡萄糖和呋喃类化合物的最新研究进展。发现在LGA溶剂热催化转化为左旋葡萄糖酮的过程中,催化剂Brønsted酸性位点及原位移除反应生成的水分有助于提升左旋葡萄糖酮的产率,最优条件下左旋葡萄糖酮的最大产率可接近60%,开发合适的催化剂及溶剂体系有助于进一步提高左旋葡萄糖酮产率。通过酸水解作用,LGA转化为葡萄糖的产率及选择性均可达近100%,且催化剂能够长时间稳定运行,该方法提供了一个由纤维素间接生产葡萄糖的方法。最后,总结了催化剂理化特性及溶剂条件对LGA生成呋喃类和酸酯类化合物的影响规律,发现葡萄糖间接转化机制可促进LGA高效转化为此类化学品。

Pyrolysis of lignocellulose is an efficient way to utilize biomass. The primary product of cellulose pyrolysis is levoglucosan(LGA), with a yield of up to 80%. Consequently, the high-value utilisation of LGA can be achieved through efficient conversion into other platform chemicals. The latest research progress on the pyrolysis of cellulose to LGA was presented, the influence of reactor types andreaction conditions on LGA yield were summarized, and biomass pretreatment could enhance the industrial scale production of LGA. ThenLGA conversion to levoglucosenone, glucose, and furan compounds under different conditions were concluded. It is found that Brønstedacid sites and in-situ removal of generated water during reaction improve levoglucosenone yield, with the maximum yield close to 60%,developing suitable catalysts and solvents can further improve levoglucosenone yield. Additionally, LGA can be effectively convertedto glucose by acid hydrolysis, attaining both yield and selectivity nearing 100%, and the catalyst with long-term stability, providing an indirect method for producing glucose from cellulose. Furthermore, the effects of catalysts and solvents on the formation of furanic compounds, acids and esters were summarized, indicating that these chemicals were formed via glucose as the intermediate.

0 引言

1 纤维素热解转化为LGA

2 LGA溶剂热转化为LGO

3 LGA转化为葡萄糖

4 LGA转化为呋喃类化合物

5 LGA转化为其他化学品

6 结语与展望