Superior cellulose-protective effects of cosolvent during enhanced dissolution in imidazolium ionic liquid
Superior cellulose-protective effects of cosolvent during enhanced dissolution in imidazolium ionic liquid
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DOI：
10.1515/hf-2015-0116
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发表时间：
2016-06-01
期刊：
影响因子：
2.4
通讯作者：
Nakajima, Noriyuki
中科院分区：
文献类型：
--
作者：
Tao, Juan;Kishimoto, Takao;Nakajima, Noriyuki
为了提高纤维素在低温下的溶解度，研究了几种极性有机溶剂作为咪唑离子液体（IL）的共溶剂。所有被测的助溶剂在较低温度下都提高了il的增溶效率。其中，n -甲基咪唑、n -甲基-2-吡咯烷酮和二甲基亚砜（DMSO）效果显著；Avicel的溶解度提高，在30℃下，1-烯丙基-3-甲基咪唑氯（[Amim]Cl）中纤维素溶解率为12-15%。IL/助溶剂体系再生纤维素的红外光谱显示了II型纤维素和/或非晶纤维素的特征。热重分析表明，与不含DMSO的再生纤维素相比，[Amim]Cl/DMSO再生纤维素的热稳定性显著提高。此外，二甲基乙酰胺（DMAc）提高了滤纸纸浆在1-乙基-3-甲基咪唑醋酸盐（[Emim]OAc）中的溶解度，在30℃下，纸浆溶解率为12%。[Emim]OAc/DMAc对纤维素的聚合度（DP）没有降低，而[Emim]OAc对纤维素的聚合度（DP）降低了8-9%。这些结果表明，一些共溶剂，包括DMSO和DMAc，在增强溶解过程中提高了溶解效率，并具有良好的纤维素保护作用。
To improve the solubility of cellulose at lower temperatures, several polar organic solvents were examined as cosolvents in imidazolium ionic liquid (IL). All tested cosolvents increased the solubilization efficiency of ILs at lower temperatures. Among these, N-methylimidazole, N-methyl-2-pyrrolidone, and dimethyl sulfoxide (DMSO) were notably efficient; in case of Avicel the solubility was increased, with 12-15% cellulose dissolution in 1-allyl-3-methylimidazolium chloride ([Amim]Cl) at 30 degrees C. IR spectra of the regenerated celluloses from IL/cosolvent systems showed characteristic features of cellulose II and/or amorphous cellulose. Thermogravimetric analyses showed significantly higher thermal stability of regenerated cellulose from [Amim]Cl/DMSO compared with that without DMSO. Moreover, dimethylacetamide (DMAc) increased the solubility of filter paper pulp in 1-ethyl-3-methylimidazolium acetate ([Emim]OAc), with 12% pulp dissolution at 30 degrees C. No decrease in the degree of polymerization (DP) of cellulose was observed with [Emim]OAc/DMAc, whereas 8-9% DP decrease was observed with [Emim] OAc, even at 30 degrees C. These results indicate that some cosolvents including DMSO and DMAc increase solubilization efficiency and have superior cellulose-protective effects during enhanced dissolution in ILs.