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合成了三种含有羧基或醚基的离子液体,1-羧甲基-3-乙基咪唑氯化物([CmEIM]Cl)、1-甲氧乙基-3-乙基咪唑氯化物([C2OC1-EIM]Cl)和1-[2-(2-氯乙氧基)乙基]-3-乙基咪唑氯化物([Cl-C2OC2-EIM]Cl),用FT-IR和1H NMR对它们的化学结构进行了表征.测定并比较了这三种离子液体对棉纤维素的溶解能力,并用FT-IR,SEM和XRD研究了溶解前和再生后纤维素的化学结构、形貌及晶体结构的变化.结果表明,在三种离子液体中,[C2OC1-EIM]Cl对棉纤维素的溶解性最好.在溶解过程中,随着温度的升高,纤维素在离子液体中的溶解度增加,但聚合度下降,特别是在[Cl-C2OC2-EIM]Cl中溶解时,纤维素的聚合度下降最严重.研究结果表明,含羧基的离子液体会由于分子间氢键的缔合作用降低其对纤维素的溶解性.侧基较大的离子液体对纤维素的溶解性也较差.
Three ionic liquids containing carboxyl groups or ether groups were synthesized, including 1-carboxymethyl-3-ethylimidazolium chloride ([CmEIM] Cl), 1-methoxyethyl-3-ethylimidazolium chloride -EIM] Cl) and 1- [2- (2-chloroethoxy) ethyl] -3- ethylimidazolium chloride ([Cl-C2OC2-EIM] Cl) The chemical structures of the cellulose were characterized and compared.The solubilities of these three kinds of ionic liquids on cotton cellulose were determined and compared.The chemical structure, morphology and crystal structure of cellulose before and after the dissolution were studied by FT-IR, SEM and XRD The results showed that [C2OC1-EIM] Cl had the best solubility for cotton cellulose in the three ionic liquids.In the process of dissolution, the solubility of cellulose in the ionic liquid increased with the increase of temperature , But the degree of polymerization decreased, especially when dissolved in [Cl-C2OC2-EIM] Cl, the degree of polymerization of cellulose decreased the most.The results show that the ionic liquid containing carboxyl will be reduced due to the association of intermolecular hydrogen bonds Its solubility in cellulose, the ionic liquid with larger pendant groups is also less soluble in cellulose.