Abstract: Several task-specific ionic liquids were prepared by 1-vinylimidazole reacted with bromoacetic acid，3-bromopropionic acid，5-bromovaleric acid and 6-bromohexanoic acid，respectively. Their structures were characterized by ¹H NMR and their Bronsted acidities were studied by IR spectra using pyridine as the spectroscopic probe. The results demonstrated that the 1-vinyl-3-acetoxyimidazolium bromide had the strongest acidity among the studied task-specific ionic liquids，the introduction of imidazolium to carboxylic acid can strengthen the acidity of corresponding carboxylic acid because of the electron-withdrawing effects of imidazolium，each task-specific ionic liquid was able to be polymerized with ethylene glycol dimethacrylate to form a white polymer which was characterized by scanning electron microscope.

Key words: ionic liquid, IR-spectrascopy, Bronsted acidity

摘要： 以1-乙烯基咪唑为原料，分别与溴乙酸、3-溴丙酸、5-溴戊酸、6-溴己酸一步合成反应，得到几种可聚合酸性离子液体。离子液体的酸度采用酸度计和吡啶红外光谱探针法进行了表征。结果表明，由于咪唑环的吸电子效应，咪唑环的引入提高了对应羧酸的酸性，红外光谱表明羧基咪唑离子液体具有Bronsted酸性，且1-乙烯基-3-乙酸基咪唑溴盐的酸性最强，它们可分别与乙二醇二甲基丙烯酸酯进行沉淀聚合，得到白色的聚合物。

关键词: 离子液体；红外光谱法, Bronsted酸