Abstract This study employs a semi-continuous reactor system to investigate the solvent effect of gamma-valerolactone (GVL) on cellulose hydrolysis in hot-compressed GVL/water (HCGW) at 250 °C and 10 MPa. The primary liquid products from cellulose hydrolysis in HCGW at various GVL concentrations are collected and characterised. Both hydrolysis reaction rate and final glucose recovery are found to increase with GVL concentration, with a high glucose recovery of 91% achieved in the primary liquid products of cellulose hydrolysis in 10% GVL/water. Further analyses of the primary liquid products using high performance anion exchange chromatography with pulsed amperometric detection show the reductions in the isomers of glucose oligomers (with reducing end as fructose and mannose) and the increases in the glucose oligomers with low degrees of polymerisation, indicating that GVL addition enhances hydrolysis reactions but suppresses isomerization reactions in the solid phase. Similar effects are also found in the secondary reactions of the primary liquid products during cellulose hydrolysis at reduced flow rates. The experimental results from biomass hydrolysis clearly demonstrate that GVL/water co-solvent is an excellent reaction medium for biomass hydrolysis under acid-free conditions, achieving a near-complete sugar recovery (i.e., 93%) at a low GVL concentration of 5%.

中文翻译：

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γ-戊内酯 (GVL) 对热压缩 GVL/水混合物中纤维素和生物质水解的溶剂影响

摘要 本研究采用半连续反应器系统研究 γ-戊内酯 (GVL) 在 250 °C 和 10 MPa 的热压缩 GVL/水 (HCGW) 中对纤维素水解的溶剂影响。收集并表征来自不同 GVL 浓度下 HCGW 中纤维素水解的主要液体产物。发现水解反应速率和最终葡萄糖回收率都随着 GVL 浓度的增加而增加，在 10% GVL/水中纤维素水解的主要液体产物中实现了 91% 的高葡萄糖回收率。使用带脉冲安培检测的高效阴离子交换色谱法对初级液体产品的进一步分析表明，葡萄糖低聚物的异构体减少（还原端为果糖和甘露糖），而低聚合度的葡萄糖低聚物增加，表明GVL 添加增强了水解反应但抑制了固相中的异构化反应。在降低流速的纤维素水解过程中初级液体产物的二次反应中也发现了类似的效果。生物质水解的实验结果清楚地表明，GVL/水共溶剂是无酸条件下生物质水解的极好反应介质，在 5% 的低 GVL 浓度下实现了近乎完全的糖回收率（即 93%） . 表明 GVL 添加增强了水解反应但抑制了固相中的异构化反应。在降低流速的纤维素水解过程中初级液体产物的二次反应中也发现了类似的效果。生物质水解的实验结果清楚地表明，GVL/水共溶剂是无酸条件下生物质水解的极好反应介质，在 5% 的低 GVL 浓度下实现了近乎完全的糖回收率（即 93%） . 表明 GVL 添加增强了水解反应但抑制了固相中的异构化反应。在降低流速的纤维素水解过程中初级液体产物的二次反应中也发现了类似的效果。生物质水解的实验结果清楚地表明，GVL/水共溶剂是无酸条件下生物质水解的极好反应介质，在 5% 的低 GVL 浓度下实现了近乎完全的糖回收率（即 93%） .