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Mass spectrometric studies of 1-ethyl-3-methylimidazolium and 1-propyl-2,3-dimethylimidazolium bis(trifluoromethyl)sulfonylimidesстатья
Информация о цитировании статьи получена из
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 19 октября 2015 г.
- Авторы: Chilingarov N.S., Medvedev A.A., Deyko G.S., Kustov L.M., Chernikova E.A., Glukhov L.M., Markov V.Yu, Ioffe I.N., Senyavin V.M., Polyakova M.V., Sidorov L.N.
- Журнал: Rapid Communications in Mass Spectrometry
- Том: 29
- Год издания: 2015
- Издательство: John Wiley & Sons Inc.
- Местоположение издательства: United States
- Первая страница: 1227
- Последняя страница: 1232
- DOI: 10.1002/rcm.7214
- Аннотация: RATIONALE: Ionic liquids ([Cat+][An]) were believed to decompose before reaching vaporization temperatures, but recently some of them have been shown to vaporize congruently. Low-temperature vaporization of ionic substances is an intriguing phenomenon, so the vapor-phase composition and reactions of ionic liquids deserve more extensive study. METHODS: Evaporation of two ionic liquids, [C2MIM+][Tf2N] and [C3MMIM+][Tf2N], was studied by means of Knudsen effusion mass spectrometry. These liquids were also characterized using matrix-assisted laser desorption/ ionization (MALDI) mass spectrometry, UV/Vis, IR, NMR spectroscopy, and elemental analysis. RESULTS: The vaporization enthalpies of (118 ± 3) and (124 ± 2) kJ·mol1 were determined for [C2MIM+][Tf2N] and [C3MMIM+][Tf2N], respectively. The corresponding equations for their saturated vapor pressures are: lnðpf½C2MIMþ½Tf2Ng=PaÞ ¼ –ð14213±325Þ=ðT=KÞ þ ð26:57±1:04Þ; lnðpf½C3MMIMþ½Tf2Ng=PaÞ ¼ –ð14868 ± 221Þ=ðT=KÞ þ ð27:19±0:60Þ: The MALDI studies (positive and negative ion modes) enabled detection of monomeric [Cat+] and [An] ions, the cluster ions {[Cat+]2[An]}+ and {[Cat+][An]2}, and some complex anions {2[An]+Na+}, {2[An]+K+}, {2[An]+Cu+} and {3[An]+Ca2+}. CONCLUSIONS: Knudsen effusion mass spectrometry proved to be a valuable method to study the thermodynamics of ionic liquids. The saturated vapor pressure and vaporization enthalpy of [C3MMIM+][Tf2N] were accurately determined for the first time. MALDI is also capable of providing indirect information on hydrogen bonding.
- Добавил в систему: Марков Виталий Юрьевич