Structural and Positional Isomerism Influence in the Physical Properties of Pyridinium NTf₂-Based Ionic Liquids: Pure and Water-Saturated Mixtures

Abstract

Density and viscosity data for six pyridinium-based ionic liquids combined with the bis[(trifluoromethyl)sulfonyl]amide anion were measured at atmospheric pressure in the (278 to 363) K temperature range. The fundamental aim of this work is to study the effect of the structure of the pyridinium-based cation, namely, its alkyl chain length and structural isomers, and the position of the second alkyl substitution on the measured properties. Albeit many studies exist on the physical properties of ionic liquids in what concerns the nature of the anion and the length of the cation alkyl side chain, the effect of structural and positional isomerism on those properties is much less known. In additionsand since small amounts of water influence the phase equilibrium and thermophysical properties of ionic liquidsswater-saturated ionic liquid samples were also studied in the (298 to 363) K temperature range. The Vogel-Tammann-Fulcher (VTF) method was applied to describe the viscosity data, and novel group contribution parameters are proposed for the ionic liquid cations presented here, thus broadening its applicability.

Study on Thermodynamic Properties of Ionic Liquid N-Butyl-3-methylpyridinium Bis(trifluoromethylsulfonyl)imide

“…The density and dynamic viscosity in the present work have a small discrepancies with the reported values 22 33 From the TG, the decomposition temperature of [C 4 3mpy][NTf 2 ] is higher than 620.0 ± 0.1 K. The samples exhibited excellent thermal stability up to 620.0 ± 0.1 K at a scanning rate of 10 K·min −1 ; the mass loss is more than 90% from the onset temperature to the terminal temperature. The percent of the mass loss at different temperatures is listed in Table 2.…”

“…1 − , such as melting temperature, glass transition temperature, dynamic viscosity, electrical conductivity, etc. have been studied by Tokuda et al 20,21 Because of a current trend of seeking for easily obtained and low-cost ILs other than alkyl imdazolium-based ILs, 14,22 the previous works of our group 14,23,24 focused on a family of pyridinium-based ILs. Some important properties of the ILs like density, surface tension, dynamic viscosity, electrical conductivity, melting temperature, and decomposition temperature were determined.…”

Density, dynamic viscosity, and electrical conductivity of pyridinium-based hydrophobic ionic liquids

“…As a stable hydrophobic ILs anion, bis(trifluoromethylsulfonyl)imide [NTf 2 ] À type ILs is especially strikingly [5][6][7]. So, the physicochemical properties of [NTf 2 ] À type ILs were probed systematically [8][9][10][11][12][13].…”

Physicochemical Properties of Ionic Liquids [C3py][NTf2] and [C6py][NTf2]

“…Oliveira et al 10 studied the properties of a series of pyridinium-based ILs. The density and dynamic viscosity of 30 the dried and saturated ILs were studied.…”