秸秆的乙醇化技术已备受关注，水热转化能破坏木质纤维结构并水解生成可发酵糖，是一种高效的预处理和水解技术。但早期水热技术表现了高温高能耗的缺陷，且各组分溶解水解同时进行，导致产物分解损失。本项目根据纤维素、半纤维素和木质素的分子结构特性和化学键差异，及其溶解水解反应对能量的不同需求，提出低温梯级水热转化实现木质纤维废物的异步溶解与水解，重点针对其中纤维素异步溶解水解的理论机理，及纤维素与半纤维素、木质素异步溶解机制和相互影响开展研究。通过考察各组分在低温水热条件下结晶性、聚合度与分子结构变化，以及化学键断裂规律，分析其溶解反应动力学，明确各组分异步溶解水解机制和突破条件；进而优化梯级低温水热工艺，先后进行无定形组分溶解、结晶组分的氢键破坏、以及溶解组分中糖苷键的断开，实现各组分异步溶解与水解，不但能避免无效能量损耗，而且能分步控制溶解水解过程，减少产物损失，为生物乙醇技术的突破奠定基础。

Because of the global fuel issues, ethanol production from crop stalks has caught much attention. Hydrothermal conversion for biomass waste, which can break the lignocellulosic structure and hydrolyze cellulose into fermentable sugars, is considered as an efficient technology for pretreatment and hydrolysis. However, early hydrothermal technologies represented disadvantages of high temperatures and high energy consumption; and could lead to synchronous dissolution and hydrolysis of cellulose, resulting in the decomposition and loss of target products. Based on the differences on molecular structures and chemical bonds of cellulose, hemicellulose and lignin, as well as the corresponding energy demands for their dissolution and hydrolysis, a multilevel low-temperature hydrothermal technology is proposed in this project to dissolve and hydrolyze lignocellulosic waste asynchronously. The research focuses are theoretical mechanisms of asynchronous dissolution and hydrolysis of cellulose, as well as asynchronous dissolution and interaction laws of cellulose, hemicellulose and lignin. The crystallinity, degrees of polymerization, and molecular structures of major components under low-temperature hydrothermal conditions will be investigated, together with the breaking law of the hydrogen and covalent bonds. The kinetics for surface reaction will thus be analyzed, and the mechanisms and critical parameters of asynchronous dissolution and hydrolysis will be determined. Subsequently, the multilevel low-temperature hydrothermal process will be optimized according to the theoretical results, to achieve dissolution of amorphous components, hydorgen bond breaking of crystalline components, and glycosidic bond breaking of dissolved components. The multilevel low-temperature hydrothermal technology for asynchronous dissolution and hydrolysis of lignocellulose can avoid noneffective energy consumption and reduce product loss by step controlling dissolution and hydrolysis processes. The results of this project are supposed to provide important theoretical basis for ethanol production from lignocellulosic waste.