Hydrothermal pretreatment with characteristic of green chemistry is considered as promising technology in the biorefineries. Using material balance and multiscale characterization techniques, the effects of process severity factor and pH on chemical behaviors of lignin‐carbohydrate complex (LCC) were systematically studied. During pretreatment, spatial relocation of lignin with covalently linked xylan facilitated local cell wall collapse. A kinetic model was established to describe the behaviors of LCC components changing with severity factor. It was found that cleavage of LCC linkage was strongly pH‐dependent. Low pH dominated cleavage of coumarate/ferulate esters which cross‐linking lignin with xylan and repolymerization of aromatics either from furfural or lignin into polymers such as pseudo lignin, while high pH which allowed the existence of soluble LCC dominated the aldol condensations from xylose to aromatics and depolymerizaton of lignin to phenols. Detailed reaction pathways concerned with LCC were finally established to elucidate the underlying mechanism. © 2018 American Institute of Chemical Engineers AIChE J, 64: 1938–1953, 2018

中文翻译：

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水热预处理对植物细胞壁的破坏：第一部分。对木质素-碳水化合物复合物的影响

具有绿色化学特征的水热预处理被认为是生物精炼厂中的有前途的技术。使用材料平衡和多尺度表征技术，系统地研究了工艺严重性因子和pH对木质素-碳水化合物复合物（LCC）的化学行为的影响。在预处理过程中，木质素与共价连接的木聚糖的空间迁移促进了局部细胞壁的塌陷。建立了动力学模型来描述LCC组分随严重性因子而变化的行为。发现LCC键的裂解强烈依赖于pH。低pH值的香豆酸酯/阿魏酸酯的裂解，使木质素与木聚糖交联，芳烃从糠醛或木质素再聚合为假木质素等聚合物，较高的pH值允许存在可溶性LCC，这主要是由木糖到芳族化合物和木质素解聚为苯酚的醛醇缩合反应。最终建立了与LCC有关的详细反应途径，以阐明其潜在机制。©2018美国化学工程师学会AIChE J，64：1938–1953，2018