Volatility study of [C(1)C(1)im][NTf2] and [C(2)C(3)im][NTf2] ionic liquids

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Rocha, MAA (Author) Other; Ribeiro, FMS (Author) Other; Schroder, B (Author) Other; Coutinho, JAP (Author) Other; Santos, LMNBF (Author) FCUP

Journal

Title: Journal of Chemical Thermodynamics

Vol. 68

Pages: 317-321

ISSN: 0021-9614

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 25 Citations

Scopus - 28 Citations

Other information

Authenticus ID: P-008-FQH

DOI: 10.1016/j.jct.2013.09.020

Abstract (EN): Vapor pressures of 1,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide, ([C(1)C(1)im][NTf2]) and 1ethyl-3-propylimidazolium bis(trifluoromethylsulfonyl) imide, ([C(2)C(3)im][NTf2]) ionic liquids were measured as a function of temperature using a Knudsen effusion apparatus combined with a quartz crystal microbalance. Enthalpies and entropies of vaporization were derived from the fitting of vapor pressure and temperature results to the Clarke and Glew equation. [C(1)C(1)im][NTf2] presents a higher enthalpy and entropy of vaporization than the neighboring members of the series. The enthalpy of vaporization of [C(2)C(3)im][NTf2] lies in between the asymmetric and symmetric ionic liquid series, reflecting a decrease in the electrostatic interactions due to a decrease of the charge accessibility between the ionic pairs when the methyl group is replaced by an ethyl group. The obtained higher volatility of [C(2)C(3)im][NTf2] arises from its asymmetric character, leading to an higher entropic contribution that compensates the enthalpic penalty. The border conditions ([C(1)C(1)im][NTf2], [C(2)C(1)im][NTf2] and [C(2)C(2)im][NTf2]), topology ([C(2)C(3)im][NTf2]) and symmetry/asymmetry of the ILs effect were evaluated and rationalized based on a comparative analysis of the thermodynamic properties, enthalpies and entropies of vaporization.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5