高等学校化学学报 ›› 2023, Vol. 44 ›› Issue (11): 20230218.doi: 10.7503/cjcu20230218

• 物理化学 • 上一篇    下一篇

熔盐水合物选择性水解纤维素制备葡萄糖

梁皓童, 林健颖, 袁绍敏, 马巧智()   

  1. 华南农业大学材料与能源学院, 广州 510642
  • 收稿日期:2023-04-28 出版日期:2023-11-10 发布日期:2023-09-01
  • 通讯作者: 马巧智 E-mail:maqzhi@scau.edu.cn
  • 基金资助:
    国家重点研发计划项目(2018YFB1501402);国家自然科学基金(51906072);广东省基础与应用基础研究基金(2023A1515011661);广州基础研究计划基础与应用基础研究项目(202201010254)

Glucose Production from Cellulose via Selective Hydrolysis in Molten Salt Hydrate

LIANG Haotong, LIN Jianying, YUAN Shaomin, MA Qiaozhi()   

  1. School of Materials and Energy,South China Agricultural University,Guangzhou 510642,China
  • Received:2023-04-28 Online:2023-11-10 Published:2023-09-01
  • Contact: MA Qiaozhi E-mail:maqzhi@scau.edu.cn
  • Supported by:
    the National Key Research and Development Program, China(2018YFB1501402);the National Natural Science Foundation of China(51906072);the Guangdong Provincial Basic and Applied Basic Research Fund, China(2023A1515011661);the Guangzhou Basic Research Program, Basic and Applied Research Project, China(202201010254)

摘要:

针对目前熔盐水合物(MSH)对纤维素的溶解、 水解机理尚不明确这一问题, 本文系统地研究了纤维素在Li+, Na+, K+, Zn2+阳离子及Cl, Br, I阴离子所组成的MSH中水解的情况, 筛选出对纤维素水解效果最佳的熔盐——LiBr, 并研究了体系酸性对水解的影响规律. 结果表明, MSH中阳离子Na+和K+在水中的有限溶解度导致没有足够的阳离子与纤维素中的氧原子配位, 无法为糖苷键断裂提供足够的路易斯酸; MSH中的阴离子Cl的电负性不足以与纤维素中的羟基形成足够的新的氢键, 纤维素溶解度不足导致水解效果较差. 在非酸化体系中, 130 ℃, 5 h的反应条件下, 纤维素在LiBr熔盐体系内可以被选择性水解为水溶性低聚糖和葡萄糖单糖, 收率分别为57.2%和29.0%. 在酸性环境下, MSH能有效催化纤维素糖苷键断裂, 质量分数0.01%(HCl)LiBr熔盐体系于100 ℃水解纤维素30 min后, 产物以寡聚葡萄糖为主, 聚合度在4~13之间. 酸性的提升可以提高糖苷键的断键效率; 质量分数0.1%(HCl)LiBr在100 ℃, 30 min条件下水解纤维素, 葡萄糖得率可以达到90.9%.

关键词: 纤维素, 葡萄糖, 熔盐水合物, 水热解聚, 酸性调控

Abstract:

To address the challenges of the unclear mechanism of cellulose dissolution and hydrolysis in molten salt hydrate(MSH). This work systematically studied the hydrolysis of cellulose in molten salts hydrate consisting of different cations(e.g., Li+, Na+, K+, Zn2+ ), and anions(e.g., Cl, Br and I), and screened the best molten salt for cellulose hydrolysis, LiBr, and studied the effect of acidity on cellulose hydrolysis. The result indicated that the limited solubility of the cation Na+ and K+ resulted in the insufficient coordination between cations and oxygen atoms in the cellulose, which cannot provide sufficient Lewis acidity for glycosidic bonds cleavage. Additionally, the anion Cl in MSH has limited electronegativity, which cannot form massive hydrogen bonds with the hydroxyl groups in cellulose, resulting in a limited solubility and thereby caused negative effect on hydrolysis. Under the reaction conditions of 130 ℃ and 5 h in a non-acidified system, cellulose can be selectively hydrolyzed into water-soluble oligosaccharides and glucose with the yield of 57.2% and 29.0%, respectively. The results also show that the MSH can catalyze the cleavage of cellulose glycoside bonds and decrease the cellulose degree of polymerization(DP) in an 0.01%(HCl) dilute acidic MSH at 100 ℃ for 30 min ranging from 4 and 13. Improvement of acidity can enhance the cleavage efficiency of glycosidic bond cleavage. When the acidity increased to 0.1%(HCl), a high yield of glucose at 90.9% can be achieved at 100 ℃ for 30 min.

Key words: Cellulose, Glucose, Molten salt hydrate, Hydrolysis, Acid regulation

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