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.

Cerium Tetrafluoride: Sublimation, Thermolysis, and Atomic Fluorine Migration.

Saturated vapor pressure p° and enthalpy of sublimation (ΔsH°) of cerium tetrafluoride CeF4 were determined by means of Knudsen effusion mass spectrometry in the range of 750-920 K. It was discovered that sublimation of cerium tetrafluoride from a platinum effusion cell competes with thermal decomposition to CeF3 in the solid phase, but no accompanying release of fluorine to the gas phase occurs. Thus, fluorine atoms migrate within the surface layer of CeF4(s) to the regions of their irreversible drain.