Interactions of pyridinium, pyrrolidinium or piperidinium based ionic liquids with water: Measurements and COSMO-RS modelling

authors	Khan, I; Taha, M; Pinho, SP; Coutinho, JAP
nationality	International
journal	FLUID PHASE EQUILIBRIA
author keywords	Activity coefficient; Water activity; COSMO-RS; Hydrogen bonding; Excess enthalpy
keywords	DILUTION ACTIVITY-COEFFICIENTS; PHYSICAL-PROPERTIES; CARBON-DIOXIDE; IMIDAZOLIUM; MIXTURES; EXTRACTION; EQUILIBRIA; SOLVENT; SYSTEMS; CATION
abstract	Looking for a better knowledge concerning water and ionic liquids (ILs) interactions, a systematic study of the activity coefficients of water in pyridinium, pyrrolidinium and piperidinium-based ILs at 298.2 K is here presented based on water activity measurements. Additionally, the study of the structural effects of the pyridinium-based cation is also pursued. The results show that non-aromatic ILs are interacting more with water than aromatic ones, and among the ortho, meta and para isomers of 1-butyl-methylpyridinium chloride, the ortho position confers a more hydrophilic character to that specific IL. The physical chemistry of the solutions was interpreted based on dissociation constants, natural bond orbitals and excess enthalpies providing a sound basis for the interpretation of the experimental observations. These results show that hydrogen bonding controls the behavior of these systems, being the anion-water one of the most relevant interactions, but modulated by the anion cation interactions. (C) 2016 Elsevier B.V. All rights reserved.
publisher	ELSEVIER SCIENCE BV
issn	0378-3812
year published	2016
volume	414
beginning page	93
ending page	100
digital object identifier (doi)	10.1016/j.fluid.2016.01.014
web of science category	Thermodynamics; Chemistry, Physical; Engineering, Chemical
subject category	Thermodynamics; Chemistry; Engineering
unique article identifier	WOS:000372686200011