Solid acid catalysts are widely used in the field of biomass catalytic conversion owing to their advantages of low environmental pollution, easy separation and reusability. Nevertheless, there are relatively few studies on the mechanism of solid acid liquefaction for biomass. In this study, the effect of acid strength and acid amount of various solid acids on the liquefaction efficiency has been investigated using waste bamboo sawdust generated from the pulp and paper industry as the raw material. In addition, the physicochemical changes of cellulose, hemicellulose and lignin during the reaction process of bamboo sawdust have been studied, and the liquefaction mechanism of bamboo sawdust under the action of various solid acids has been concluded. As a result, the liquefaction efficiency of bamboo sawdust under the polyol system of PEG400/propanetriol is mainly related to the acid strength of the solid acid, and the greater the acid strength of the solid acid, the better the catalytic effect on the bamboo sawdust, in which the residual amount of bamboo sawdust liquefaction catalyzed by the SPA catalyst is only 17.72%. Noteworthy, the most difficult component to liquefy is the crystallization of natural cellulose I into cellulose II during the reaction process, which is the primary obstacle to the complete liquefaction of bamboo sawdust by solid acid. Overall, these findings are valuable for the high value utilization of waste bamboo sawdust in the pulp and paper industry, as well as the application of solid acid catalytic technology for biomass.

中文翻译：

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多元醇体系下固体酸催化竹木屑液化机理

固体酸催化剂具有环境污染低、易分离、可重复利用等优点，广泛应用于生物质催化转化领域。然而，对于生物质固体酸液化机理的研究相对较少。本研究以制浆造纸工业产生的废竹木屑为原料，研究了各种固体酸的酸强度和酸量对液化效率的影响。此外，还研究了竹锯末反应过程中纤维素、半纤维素和木质素的物理化学变化，总结了竹锯末在各种固体酸作用下的液化机理。由此可见，竹木屑在PEG400/丙三醇多元醇体系下的液化效率主要与固体酸的酸强度有关，固体酸的酸强度越大，对竹木屑的催化效果越好，其中SPA催化剂催化竹木屑液化残留量仅为17.72%。值得注意的是，最难液化的成分是反应过程中天然纤维素I结晶成纤维素II，这是固体酸完全液化竹木屑的首要障碍。总体而言，这些研究结果对于废竹锯末在制浆造纸工业中的高值化利用以及固体酸催化技术在生物质中的应用具有重要价值。