Preparation And Application Of Ionic Liquids As Stationary Phase In Gas Chromatography

The ionic liquid is composed by the anion and cation. It can be designed and the meltingpoint is low.The special structure of ionic liquids decide a greater potential in separation ofcomplicated samples as the chromatographic stationary phase.In the paper, three kinds ofionic liquis were syntheszed.Poly1-allyl-ethyl-benzimidazole hexafluorphosphate（[PAeBIm][PF₆]）, Poly1-allyl-3-methylimidazolium hexafluorophosphate （[PAMIM][PF₆]）and1-ethyl-（γ-chloropropyl） trimethoxysilane benzo hexafluorophosphate（[SOeBim][PF₆]）.The characterized of the ionic liquids were characterized by IR methodand NMR. The decomposition temperature was analyzed by TG and the results show that thedecomposition temperature are300℃，250℃and220℃respectively,so the maximumoperating temperature are270℃，220℃and190℃.The reaction conditions were optimized：Reaction time of [PAeBIm][PF₆],[PAMIM][PF₆] and [SOeBim][PF₆] are10h,8h and10hrespectively; Reaction temperature are80℃,60℃and100℃respectively and the yield are93.3%,91.7%and80.0%.The relative polarities of [PAeBIm][PF₆] and [PAMIM][PF₆] weredetermined as+3and+3.[PAeBIm][PF₆] and [PAMIM][PF₆] as stationary phase were made into packed columnsfor gas chromatography.The stationary liquid of [SOeBim][PF₆] was bonded to the inner ofcapillary column with the method of chemical bonding and was made into[SOeBim][PF₆]-linked capillary column.[PAeBIm][PF₆] and [PAMIM][PF₆] exhibitedsatisfactory resolution and chromatographic selectivity for alcohols mixture,aromaticsmixture and alkane mixture.The capillary column of [SOeBim][PF₆] exhibited satisfactoryresolution and chromatographic selectivity for several kinds of benzene and alcohols mixture.