3 research outputs found
Transport Properties and Ionic Association in Pure Imidazolium-Based Ionic Liquids as a Function of Temperature
In this work, three transport properties
(viscosity, diffusion
coefficient, and electrical conductivity) were experimentally determined
from 298 K to 343 K in four pure imidazolium-based ionic liquids with
two anions and different alkyl chain lengths on the cation: 1-ethyl-3-methylimidazolium
methylsulfate, [C<sub>1</sub>C<sub>2</sub>Im][CH<sub>3</sub>SO<sub>4</sub>], 1-butyl-3-methylimidazolium methylsulfate, [C<sub>1</sub>C<sub>4</sub>Im][CH<sub>3</sub>SO<sub>4</sub>], 1-ethyl-3-methylimidazolium
triflate, [C<sub>1</sub>C<sub>2</sub>Im][CF<sub>3</sub>SO<sub>3</sub>] and 1-butyl-3-methylimidazolium triflate, [C<sub>1</sub>C<sub>4</sub>Im][CF<sub>3</sub>SO<sub>3</sub>]. Higher viscosities, lower diffusion
coefficients, and electrical conductivities were measured when the
alkyl chain length was increased or a sulfate anion was present. From
these experimental data, the ionic association was discussed using
the qualitative approach of the Walden plots and the quantitative
ionicity concept. An increased ionic association was observed when
the alkyl chain length on the cation was increased, while comparable
ionicities were measured for both anions. Finally, the applicability
of the Stokes–Einstein equation (relation between the diffusion
coefficient and the viscosity) was also discussed in these systems
Transport properties and ionic association in pure imidazolium-based ionic liquids as a function of temperature.
International audienceIn this work, three transport properties (viscosity, diffusion coefficient, and electrical conductivity) were experimentally determined from 298 K to 343 K in four pure imidazolium-based ionic liquids with two anions and different alkyl chain lengths on the cation: 1-ethyl-3-methylimidazolium methylsulfate, [C1C2Im][CH3SO4], 1-butyl-3-methylimidazolium methylsulfate, [C1C4Im][CH3SO4], 1-ethyl-3-methylimidazolium triflate, [C1C2Im][CF3SO3] and 1-butyl-3-methylimidazolium triflate, [C1C4Im][CF3SO3]. Higher viscosities, lower diffusion coefficients, and electrical conductivities were measured when the alkyl chain length was increased or a sulfate anion was present. From these experimental data, the ionic association was discussed using the qualitative approach of the Walden plots and the quantitative ionicity concept. An increased ionic association was observed when the alkyl chain length on the cation was increased, while comparable ionicities were measured for both anions. Finally, the applicability of the Stokes–Einstein equation (relation between the diffusion coefficient and the viscosity) was also discussed in these systems