Ma Yue, Xia Qinqin, Liu Yongzhuang, Chen Wenshuai, Liu Shouxin, Wang Qingwen, Liu Yixing, Li Jian, Yu Haipeng
Key Laboratory of Bio-based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, P. R. China.
ACS Omega. 2019 May 15;4(5):8539-8547. doi: 10.1021/acsomega.9b00519. eCollection 2019 May 31.
Pretreatment approaches are highly desirable to improve the commercial viability of nanocellulose production. In this study, we propose a new approach to mass produce nanocellulose using a hydrated choline chloride/oxalic acid dihydrate deep eutectic solvent (DES) combined with an ultrasonic process. The hydrogen bond acidity, polarizability, and solvation effect reflected by the Kamlet-Taft solvatochromic parameters did not decrease even after the addition of large amounts of water. Instead, the water facilitated the ionization of H and delocalization of Cl ions, forming new Cl-HO ionic hydrogen and oxalate-HO hydrogen bonds, which are critical for improving the solvent characteristics. One pass of kraft pulp through the hydrated DESs (80 °C, 1 h) was sufficient to dissociate the kraft pulp into cellulose nanofibers or cellulose nanocrystals using an 800 W ultrasonic treatment. The present study represents an alternative route for the kraft pulp pretreatment and the large-scale production of nanocellulose.
预处理方法对于提高纳米纤维素生产的商业可行性非常必要。在本研究中，我们提出了一种新方法，即使用水合氯化胆碱/二水合草酸深共熔溶剂（DES）结合超声工艺大规模生产纳米纤维素。由Kamlet-Taft溶剂化显色参数反映的氢键酸度、极化率和溶剂化效应即使在加入大量水后也不会降低。相反，水促进了H的电离和Cl离子的离域，形成了新的Cl-HO离子氢键和草酸盐-HO氢键，这对于改善溶剂特性至关重要。使用800W超声处理，将牛皮纸浆通过水合DESs（80°C，1小时）一次就足以将牛皮纸浆解离成纤维素纳米纤维或纤维素纳米晶体。本研究为牛皮纸浆预处理和纳米纤维素的大规模生产提供了一条替代途径。
