Measurements of ionic liquids thermal conductivity and thermal diffusivity

Abstract

Thermal conductivity and thermal diffusivity of ionic liquids (ILs) are investigated in this work. A hot disk method for ILs thermal conductivity and thermal diffusivity measurement is utilized. Firstly, the thermal conductivity of water is measured to check the reliability of the hot disk method. In addition, the thermal conductivity of pure ILs, including BmimBF4, BmimPF6, OmimCl, BmimFeCl4, and OmimFeCl4, is measured. By comparison with thermal conductivity values of water, BmimBF4, and BmimPF6 in the literatures, it is found that the thermal conductivity values of ILs using hot disk method has high reliability. Therefore, the hot disk method is utilized for thermal conductivity measurement of ILs in this work. The experimental results also show that all the average thermal conductivity values of the 5 pure ILs are no more than 0.1898 Wm -1 K -1 , which is much lower than the average measured thermal conductivity of water, namely 0.6033 Wm -1 K -1 . Effect of nanoparticles (NPs) on thermal conductivity of ILs is also investigated.It is shown that the thermal conductivity of BmimBF4 does not change significantly in the presence of 2 diffusivity of water is 0.143 mm 2 s -1 in the literature. It illustrates that the ILs also have a better thermal property than water for energy storage. ILs may be utilized as novel materials for energy storage. Effect of NPs on thermal diffusivity of ILs is also investigated. The results are similar to how NPs influence thermal conductivity of BmimBF4 and BmimPF6. In the presence of Fe2O3 NPs, thermal diffusivity of BmimBF4 does not change significantly. However, in the presence of R711 NPs, thermal diffusivity of BmimPF6 decreases somewhat.

Dynamic Light Scattering for Studying Mutual Diffusion Coefficients in Electrolyte Systems Comprised Entirely of Ions

“…Table IV shows that all diffusivity values obtained in the present study are on the order of (10 −12 to 10 −10 ) m 2 •s −1 , which is compared in the following with other diffusivity data that could be measured with DLS for similar systems. Thermal diffusivities a of pure ILs 78,79 and of mixtures consisting of ILs with dissolved gases 55 are typically in the range between (1 and 10) × 10 −8 m 2 •s −1 for the investigated temperature range. For mixtures of ILs with molecular components exhibiting higher volatilities, mutual diffusion coefficients were found to be in the range from (10 −11 to 10 −9 ) m 2 •s −1 .…”

Influence of the Use of an Ionic Liquid as Pre-Hydrodistillation Maceration Medium on the Composition and Yield of Cannabis sativa L. Essential Oil

“…This, combined with low flammability, made them an attractive alternative to traditional volatile organic solvents. Other intriguing properties of ionic liquids are their high thermal stability, the ability to dissolve a variety of inorganic [ 22 ] and organic [ 23 ] substrates, including biopolymers [ 24 , 25 ] and high thermal [ 26 ] and electrical conductivity [ 27 ]. Perhaps, the most outstanding feature of ILs is the possibility to tailor their properties on an application of interest by pairing the best matching ions, earning them the title of designer solvents.…”

Measurement of the Thermal Conductivity of 1-Butyl-3-methylimidazolium l-Tryptophan + Water + Ethanol Mixtures at T = (283.15 to 333.15) K

“…Ionic liquids (ILs) have attracted widespread attention in recent years as environmental friendly solvents and have been utilized in extraction, gas absorption, chemical catalysis, and other fields because of their negligible vapor pressure, higher thermal stability, good solubility, and adjustable structure. − Thermal conductivity is the measurement of the heat transfer ability of materials, and the study of thermal conductivity is significant for the scale-up and industrialization of the chemical engineering process, as for the application of ILs. − The hot wire method is an important technique for thermal conductivity measurements, which was considered to be the most stable and accurate method for fluid measurements. − For example, Tomida et al studied the thermal conductivities of several kinds of imidazolium-based ionic liquids with different alkyl chain lengths by the hot wire method and the pressure dependences of the thermal conductivity of ILs. Castro et al measured the thermal conductivities of several kinds of alkyl-methyl­imidazolium ionic liquids and corresponding IoNanofluids composed of ionic liquids with a few multiwalled carbon nanotubes (MWCNTs) dispersed.…”

“…[1][2][3] Thermal conductivity is the measurement of the heat transfer ability of the materials and the study of thermal conductivities is significant for scale-up and industrialization of the chemical engineering process, so as for the application of ILs. [4][5][6][7] Hot wire method is an important technique of thermal conductivity measurement, which was considered as the most stable and accurate method for fluid measurement. [8][9][10] For example, Tomida et al 11 studied the thermal conductivities of several kinds of imidazolium-based ionic liquids with different alkyl chain lengths by hot wire method and the pressure dependences of the thermal conductivity of ILs.…”