摘要
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.
Ionic liquids of 1-carboxymethyl-3-ethylimidazolium chloride （[CmEIM]Cl）, 1-methoxyethyl-3-ethylimidazolium chloride （[C2OC1-EIM]Cl） and 1-[2-（2-chloroethoxy）ethyl]-3-ethylimidazolium chloride （[Cl-C2OC2-EIM]Cl） were synthesized, and their chemical structures were confirmed by FT-IR and 1H NMR. Dissolution of cotton cellulose in these three kinds of ionic liquids was studied. The chemical structures, morphologies and crystalline forms of the original cellulose and the regenerated cellulose were analyzed by FT-IR, XRD and SEM, respectively. The results show that the solubility of cotton cellulose in [C2OC1-EIM]Cl was best. In the dissolution progress, the solubility of cotton cellulose in the ionic liquids increased with increasing temperature, but the DP decreased, especially in [Cl-C2OC2-EIM]Cl. It was suggested that the solubility of cotton cellulose in [CmEIM]Cl containing carboxyl decreased because of its intermolecular and intramolecular hydrogen bonds. The ionic liquids with long side chains exhibited worse dissolution ability for cotton cellulose.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2009年第10期1116-1122,共7页
Acta Chimica Sinica
基金
国家自然科学基金(No.50773017)资助项目
关键词
离子液体
合成
棉纤维素
溶解
再生
ionic liquid
synthesis
cotton cellulose
dissolution
regeneration
