How Does the Addition of a Third Ion Affect the Molecular Interactions and the Thermodynamic Properties of Acetate-Based Ionic Liquids?

Author(s)

Otero, I. ^{[1, 2]} ; Lepre, L. F. ^[3] ; Dequidt, A. ^{[1, 2]} ; Husson, P. ^{[1, 2]} ; Costa Gomes, M. F. ^{[1, 2]}

Affiliation

^[1] CNRS, Inst Chim Clermont Ferrand, BP 80026, F-63171 Aubiere - France

^[2] Univ Clermont Auvergne, BP 80026, F-63171 Aubiere - France

^[3] Univ Sao Paulo, Dept Quim Fundamental, Lab Espect Mol, Inst Quim, CP 26077, BR-05513970 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of Physical Chemistry B; v. 121, n. 41, p. 9725-9736, OCT 19 2017.
• Web of Science Citations: 4

Abstract

The effect of the addition of a third ion to the ionic liquid 1-butyl-3-methylimidazolium acetate {[}C(4)C(1)Im]-{[}OAc] was studied through the measurement of the enthalpy of mixing and of the excess molar volume of its mixtures with 1-butyl-3-methylimidazolium trifluoroacetate {[}C(4)C(1)Im]-{[}CF3CO2], 1-butyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide {[}C(4)C(1)Im]{[}NTf2], and tetrabutylphosphonium acetate {[}P-4444]{[}OAc]. Negative enthalpies of mixing (Delta H-mix < 0) and positive excess molar volumes (V-E > 0) were observed in all cases. The infrared and NMR studies of the pure ionic liquids and their mixtures show that the presence of a third ion with a weaker affinity with the common counterion contributes to prevailing the more favorable hydrogen-bond, herein always between the imidazolium cation and the acetate anion. Both radial and spatial distribution functions calculated by molecular simulation confirm this behavior. The remarkable enhancement of the viscosities of the {[}C(4)C(1)Im]{[}OAc] + {[}P-4444]{[}OAc] mixtures could be discussed in light of the calculated friction coefficients. (AU)

• FAPESP's process: 13/23234-7 - Ionic Liquids for CO2 Capture: Physical vs. Chemical Absorption.
• Grantee: Luiz Fernando Lepre
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/07145-0 - Ionic liquids for carbon dioxide capture
• Grantee: Luiz Fernando Lepre
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate