毛竹半纤维素在1-丁基-3-甲基咪唑型离子液体中的溶解性能  

Dissolution of bamboo hemicellulose in 1-butyl-3-methyl imidazolium ionic liquid

作　　者：袁林 彭红[1,3] 何鸿伟[1,3] 胡莉芳 张宇 夏琪 阮榕生 张锦胜[1,3] 彭文屹[1,2] 刘玉环 YUAN Lin;PENG Hong;HE Hongwei;HU Lifang;ZHANG Yu;XIA Qi;RUAN Rongsheng;ZHANG Jinsheng;PENG Wenyi;LIU Yuhuan(Engineering Research Center of Biomass Conversion, Ministry of Education, Nanchang University, Nanchang 330047, Jiangxi,China;School of Materials Science and Engineering, Nanchang University, Nanchang 330047, Jiangxi, China;State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, Jiangxi, China)

机构地区：[1]南昌大学生物质转化教育部工程研究中心,江西南昌330047 [2]南昌大学材料科学与工程学院,江西南昌330047 [3]南昌大学食品科学与技术国家重点实验室,江西南昌330047

出　　处：《化工进展》2019年第9期4342-4351,共10页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(21666022);江西省教育厅科学技术研究项目(GJJ150189)

摘　　要：以毛竹半纤维素为模型物,测定了其在40~150℃温度时在Bmim[HOCH2COO]、Bmim[H2NCH2COO]、Bmim[CH3CHOHCOO]、Bmim[CH2CHCOO]和Bmim[C6H5COO] 5种ILs中的溶解度,并比较被ILs溶解处理前后半纤维素的物理化学特性差异。随后借助1H NMR和13C NMR技术分析半纤维素在ILs中的溶解机理。结果表明:半纤维素的溶解度受温度和ILs的阴离子结构影响较大;半纤维素在Bmim[CH3CHOHCOO]和Bmim[HOCH2COO]中溶解度非常小,最大值只有0.56g/100g IL,而在Bmim[H2NCH2COO]和Bmim[CH2CHCOO]中分别在110℃和130℃溶解度达到峰值3.17g/100g和4.02g/100g IL;在Bmim[H2NCH2COO]、Bmim[CH2CHCOO]和Bmim[C6H5COO]中的溶解过程中半纤维素几乎不发生降解,骨架化学结构未发生改变;羧酸阴离子可能与半纤维素的羟基质子形成氢键,咪唑阳离子中C2-H酸性质子可能与半纤维素的羟基氧形成氢键,导致半纤维素分子间和分子内氢键破坏,从而使得半纤维素溶解;咪唑阳离子和羧酸阴离子共同促进半纤维素的溶解,但阴离子起主导作用。In this work, hemicellulose from bamboo was selected as model, and the solubilities of bamboo hemicellulose in Bmim[HOCH2COO], Bmim[H2NCH2COO], Bmim[CH3CHOHCOO], Bmim[CH2CHCOO], and Bmim[C6H5COO] were separately determined at the temperature ranging from 40℃ to 150℃. The regenerated hemicellulose from Bmim[H2NCH2COO], Bmim[CH2CHCOO], and Bmim[C6H5COO] was characterized and compared with the original hemicellulose. Meanwhile, 1H NMR and 13C NMR techniques were adopted to elucidate the dissolution mechanism of bamboo hemicellulose in the ILs. The results showed that the solubility of hemicellulose was greatly affected by the temperature and the anion structure of ILs. The solubilities of hemicellulose in Bmim[CH3CHOHCOO] and Bmim[HOCH2COO] were very low, and the highest value was only 0.56g/100g IL. However, the highest solubility data in Bmim[H2NCH2COO] and Bmim[CH2CHCOO] reached 3.17g/100g IL at 110℃and 4.02g/100g IL at 130℃, respectively. Almost no degradation happened during the dissolution process of hemicellulose in the ILs, leading to the maintenance of backbone structure. The hydrogen bond possibly formed between the carboxylic anion and the proton of hydroxyl groups from hemicellulose and between the acidic proton at C2 from imidazolium cation and the oxygen of hydroxyl groups from hemicellulose, leading to the damage of the inter- and intra-hydrogen bonds in hemicellulose, and sequentially the dissolution of hemicellulose in the ILs. The imidazolium cation and carboxylic anion performed synergy for the dissolution of hemicellulose. However, the carboxylic anion played the main role.

关 键 词：咪唑离子液体 半纤维素 溶解度 溶解机理 氢键 

分 类 号：O629.12[理学—有机化学] O626.23[理学—化学]