Journal
JOURNAL OF PHYSICAL CHEMISTRY B
Volume 116, Issue 35, Pages 10922-10927Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jp306937f
Keywords
-
Categories
Funding
- Fundacao para a Ciencia e Tecnologia (FCT), Lisbon, Portugal
- FEDER
- FCT
- European Social Fund (ESF) [SFRH/BD/60513/2009]
- FCT [PTDC/CTM/103664/2008]
Ask authors/readers for more resources
This work reports the first data for the vapor pressures at several temperatures of the ionic liquids, [C(N/2)C(N/2)im][NTf2] (N = 4, 6, 8, 10, 12) measured using a Knudsen effusion apparatus combined with a quartz crystal microbalance. The morphology and the thermodynamic parameters of vaporization derived from the vapor pressures, are compared with those for the 1-alkyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide series, [C(N-1)C(1)im][NTf2] (N = 3 - 9, 11, and 13). It was found that the volatility of [C(N/2)C(N/2)im][NTf2] series is significantly higher than the asymmetric cation ILs with the same total number of carbons in the alkyl side chains, [C(N-1)C(1)im][NTf2]. The observed higher volatility is related with the lower enthalpy of vaporization. The symmetric cation, [C(N/2)C(N/2)im][NTf2], presents lower entropies of vaporization compared with the asymmetric [C(N-1)C(1)im][NTf2], indicating an increase of the absolute liquid entropy in the symmetric cation ILs, being a reflection of a change of the ion dynamics in the IL liquid phase. Moreover both the enthalpy and entropy of vaporization of the [C(N/2)C(N/2)im][NTf2] ILs, present a clear odd-even effect with higher enthalpies/entropies of vaporization for the odd number of carbons in each alkyl chain ([C(3)C(3)im][NTf2] and [C(5)C(5)im][NTf2]).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available