Intrinsic Mobility of Gaseous Cationic and Anionic Aggregates of Ionic Liquids

Abstract

Travelling-wave ion mobility mass spectrometry was used to measure the intrinsic mobility of a series of gaseous supra-cation and supra-anion aggregates of several ionic liquids. Close mobilities were observed in a T-wave cell filled with helium at ca. 0.8 mbar for [(DAI)(n+1)(X)(n)](+) (DAI is the 1,3-dialkylimidazolium cation and X is the anion) as compared to the respective anions [(DAI)(n)(X)(n+1)](-) for n=0 to 9. The anomalous behavior reported before in the condensed phase seems therefore to be related to the unique structural organization of pure ionic liquids that provides both polar and non-polar regions with directionality in which the anionic species are more retained than the cationic species in the salt network.

A Rational Approach to CO2 Capture by Imidazolium Ionic Liquids: Tuning CO2 Solubility by Cation Alkyl Branching

“…Cation diffusion constants, D cation , were extracted from 1 H spectra; anion diffusion constants, D anion , were extracted from 19 F spectra; and CO 2 diffusion constants were obtained from 13 C spectra. In every neat IL at 298 K, for which self‐diffusion was measured, the cation had a higher diffusion coefficient than the anion; this is common for most neat Im ILs 38. Also, both the increase in temperature and CO 2 solubilization have an effect on decreasing the viscosity, and consequently, are associated with higher diffusion.…”

“…To evaluatet he possibility of errors in the diffusion coefficients due to convection arising from temperature gradients forming along the NMR tube axis, experiments with the double stimulated echo for convection compensation were also performed, but the results were identical. [38] Also, both the increase in temperature and CO 2 solubilization have an effect on decreasing the viscosity,a nd consequently,a re associated with higherd iffusion. In every neat IL at 298 K, for which self-diffusion was measured, the cation had ah igherd iffusion coefficient than the anion;t his is common for most neat Im ILs.…”

“…In every neat IL at 298 K, for which self-diffusion was measured, the cation had ah igherd iffusion coefficient than the anion;t his is common for most neat Im ILs. [38] Also, both the increase in temperature and CO 2 solubilization have an effect on decreasing the viscosity,a nd consequently,a re associated with higherd iffusion. Chain elongation from linear 1 to 2 results in lower viscosities at 313 K, and higher diffusion coefficients for cation and anion diffusion coefficients for CO 2 in these ILs achieves higher values for the shorter chain length, despite the lower CO 2 molar fraction.C omparing the diffusion coefficient of CO 2 at 10 bar and 298 Ki nf luorinated IL 3 with non-fluorinated IL 1, we observe slower diffusion of CO 2 ,w hich possibly indicates focus of the interaction with CF 3 groups in the cation;t his is in accordance with our MD results.…”

Product ion mobility as a promising tool for assignment of positional isomers of drug metabolites

“…The ApexTrack™ algorithm in Driftscope takes into account the shape of the peak during CCS calculation, allowing a better differentiation of ions which have small differences in CCS. The T‐wave instrument was calibrated using a well‐established protocol . Calibration of the drift time cross‐section function was achieved by the analysis of a 10 μM polyalanine solution in methanol/water (50:50; v/v) under exactly the same ion mobility and mass spectrometric conditions.…”

“…The T-wave instrument was calibrated using a well-established protocol. [13,14,16,17] Calibration of the drift time cross-section function was achieved by the analysis of a 10 mM polyalanine solution in methanol/water (50:50; v/v) under exactly the same ion mobility and mass spectrometric conditions. The measured drift times of the polyalanine acids with varying length were plotted against the CCSs determined on a standard IMS drift tube instrument.…”