abstract
Experimental data for the density, viscosity, refractive index, and surface tension of four sulfonium- and ammonium-based ionic liquids (ILs) with the common bis(trifluoromethylsulfonyl)imide anion were measured in the temperature range between 288.15 and 353.15K and at atmospheric pressure. The ILs considered include butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N-4111][NTf2], tributyl-methylammonium bis(trifluoromethylsulfonyl)imide, [N-4441][NTf2], diethylmethylsulfonium bis(trifluoromethylsulfonyl)imide, [S-221] [NTf2], and triethylsulfonium bis(trifluoromethylsulfonyl)imide, [S-222][NTf2]. Based on the gathered results and on data taken from literature, the impact of the cation isomerism and of the size of the aliphatic tails, as well as the effect resulting from the substitution of a nitrogen by a sulfur atom as the cation central atom, on the thermophysical properties of sulfonium- and ammonium-based Its is discussed here. Remarkably, more symmetric cations present a lower viscosity for the same, and sometimes even for higher, alkyl chain lengths at the cation. Additional derivative properties, such as the isobaric thermal expansion coefficient, the surface thermodynamic properties and the critical temperature for the investigated ILs were also estimated and are presented and discussed. (C) 2014 Elsevier B.V. All rights reserved.
keywords
TEMPERATURE MOLTEN-SALTS; EXTENDED PRESSURE RANGE; SENSITIZED SOLAR-CELLS; SURFACE-TENSION MEASUREMENTS; THERMODYNAMIC PROPERTIES; PHYSICOCHEMICAL PROPERTIES; ELECTROCHEMICAL PROPERTIES; LOW-VISCOSITY; CARBON-DIOXIDE; BIS(TRIFLUOROMETHYLSULFONYL)IMIDE ANION
subject category
Thermodynamics; Chemistry; Engineering
authors
Bhattacharjee, A; Luis, A; Santos, JH; Lopes-da-Silva, JA; Freire, MG; Carvalho, PJ; Coutinho, JAP
our authors
Andreia Veríssimo Luís
Research Fellowship
Arijit Bhattacharjee
Post-doc Fellowship
João Henrique Picado Madalena Santos
PhD Student
Mara Guadalupe Freire Martins
Coordinating Researcher
Pedro J. Carvalho
Assistant ProfessorGroups
G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
Projects
Igy Technology: A Purication Platform using Ionic-Liquid-Based Aqueous Biphasic Systems (IGYPURTECH)
acknowledgements
The authors acknowledge FEDER funds through the COMPETE operational program and Fundacao para a Ciencia e Tecnologia-FCT through the projects PTDC/QUI-QUI/121520/2010 and PEst-C/CTM/LA0011/2013. P.J.C. and A.B. also acknowledge FCT for their post-doctoral grants SFRH/BPD/82264/2011 and SFRH/BPD/77858/2011, respectively. M. G. Freire acknowledges the European Research Council (ERC) for the starting Grant ERC-2013-StG-337753.