State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.
Molecules. 2017 Aug 27;22(9):1419. doi: 10.3390/molecules22091419.
Recently, IL/cosolvent systems have generated a lot of interest as cellulose-dissolving solvents and reaction media for various kinds of cellulose modification. In the present study, both 1-allyl-3-methylimidazolium chloride (AmimCl)/dimethyl sulfoxide (DMSO) and AmimCl/,-dimethylformamide (DMF) systems were employed to synthesize cellulose acetate by transesterification. Microcrystalline cellulose, 1,8-diazabicyclo[5.4.0]undec-7-ene and isopropenyl acetate were chosen as the raw material, catalyst and acetylation reagent, respectively. The results revealed that DMSO was a suitable cosolvent for the transesterification in the homogeneous solution. Moreover, DMSO had a positive effect on the reaction as the cosolvent under the given conditions and the degree of the substitution of cellulose acetate could be significantly enhanced through increasing the molar ratio of DMSO. The synthesized products were characterized by Fourier transform infrared (FT-IR) spectroscopy, ¹H and C nuclear magnetic resonance spectroscopy (¹H-NMR and C-NMR), correlation spectroscopy (COSY), heteronuclear single quantum correlation (HSQC) spectroscopy, and X-ray diffraction (XRD) to confirm the chemical and physical structure of the cellulose acetate generated. The thermal properties were also evaluated using thermogravimetric analysis (TGA)/derivative thermogravimetry (DTG).
最近，IL/共溶剂体系作为纤维素溶解溶剂和各种纤维素改性的反应介质引起了广泛关注。在本研究中，采用 1-烯丙基-3-甲基咪唑氯化物（AmimCl）/二甲基亚砜（DMSO）和 AmimCl/-二甲基甲酰胺（DMF）体系通过酯交换法合成醋酸纤维素。微晶纤维素、1,8-二氮杂二环[5.4.0]十一-7-烯和异丙烯基醋酸酯分别被选为原料、催化剂和乙酰化试剂。结果表明，在均相溶液中，DMSO 是酯交换的合适共溶剂。此外，在给定条件下，DMSO 作为共溶剂对反应具有积极影响，通过增加 DMSO 的摩尔比可以显著提高醋酸纤维素的取代度。通过傅里叶变换红外（FT-IR）光谱、¹H 和 C 核磁共振光谱（¹H-NMR 和 C-NMR）、相关光谱（COSY）、异核单量子相关（HSQC）光谱和 X 射线衍射（XRD）对合成产物进行了表征，以确认生成的醋酸纤维素的化学和物理结构。还使用热重分析（TGA）/导数热重分析（DTG）评估了热性能。
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