木质纤维素具有天然的组分异质性。分离碳水化合物和木质素组分并分别高效利用可促进木质纤维素全组分高值化利用。传统纤维素溶剂在温和条件水解糖化碳水化合物组分，但原料处理浓度低且分离的木质素组分利用价值有限。本项目结合前期研究结果，提出以低粘度水合熔融盐为溶剂并通过间歇补料，高浓糖化木质纤维素，同时分离未缩合木质素组分进行催化氢解。利用酸性水合熔融盐对糖苷化反应的促进作用，拟研究木质纤维素在高浓糖化条件下，碳水化合物水解的选择性和寡聚糖的生成机制。通过分析未溶解的木质素组分，拟研究糖化条件对未缩合木质素结构（苯并二恶烷和希伯特酮）的影响。通过调控催化剂的活性位点，拟探索未缩合木质素组分经催化氢解制备小分子单酚化合物的方法。本项目研究有望实现木质纤维素在环境友好的条件下有效分离碳水化合物和木质素，高效制备单糖、功能性寡聚糖和木质素单酚。

Lignocellulose features a congenital heterogeneity in compositions. Fractionation of lignocellulose to carbohydrates and lignin facilitates the whole-biomass valorization by maximizing the conversion efficiency of each fraction. Cellulose solvents were used to saccharify lignocellulose to soluble sugars, but the feedstock loading was low and the isolated lignin was of limited value. This proposal aims high-gravity saccharification of lignocellulose and isolation of uncondensed lignin in molten salt hydrates of low viscosity using a fed-batch technique. Since acidic molten salt hydrates favor glycosylation between sugars, the selectivity of carbohydrate hydrolysis and the mechanism of oligosaccharides formation will be studied in the high gravity saccharification of lignocellulose. The formation of uncondensed lignin structures (benzodioxane and Hibbert ketone) will be investigated under varied saccharification conditions by analyzing the chemical structures of the insoluble lignin fraction. Catalytic hydrogenolysis of the uncondensed lignin to aromatic monomers will be tested by adjusting the active sites of catalysts. This proposal offers a promising way to achieve lignocellulose fractionation under environmentally friendly conditions for the efficient production of monosaccharides, functional oligosaccharides and aromatic monomers.