Evaporation Study of an Ionic Liquid with a Double-Charged Cation.

The evaporation of a dicationic ionic liquid, 1,3-bis(3-methylimidazolium-1-yl)propane bis(trifluoromethanesulfonyl)amide ([C(MIm)][TfN]), was studied by Knudsen effusion mass spectrometry. Its evaporation is accompanied by a partial thermal decomposition producing monocationic ionic liquids, 1,3-dimethylimidazolium and 1-(2-propenyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amides, as volatile products. This decomposition does not affect the vaporization characteristics of [C(MIm)][TfN], which were established to be as follows.

Unstable Isomer of C90 Fullerene Isolated as Chloro Derivatives, C90 (1)Cl10/12.

High-temperature chlorination of C90 -containing fullerene fraction resulted in the isolation and X-ray structural characterization of C90 (1)Cl10/12 , the first derivatives of a relatively unstable isomer D5h -C90 (1) with a nanotubular shape. In the crystal structure, three isomers of both C90 (1)Cl10 and C90 (1)Cl12 with similar chlorination patterns co-crystallize in the same crystallographic site. Thus, in contrast to the previous reports, D5h -C90 (1) is present, though with a low abundance, in the fullerene soot produced by arc-discharge method with undoped graphite rods.

Mass spectrometric studies of 1-ethyl-3-methylimidazolium and 1-propyl-2,3-dimethylimidazolium bis(trifluoromethyl)-sulfonylimides.

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(+)][Tf2 N(-)] and [C3MMIM(+)][Tf2N(-)], was studied by means of Knudsen effusion mass spectrometry.