Estimation of Ionic Conductivity and Viscosity of Ionic Liquids Using a QSPR Model

Abstract

COO. To determine the coefficients in nonlinear polynomial expansion equations, genetic algorithms were adapted. The calculated results gave a reasonable correlation accuracy of ionic conductivity and viscosity. After building the polynomial expansion equations, quantitative analyses were done for each descriptor, and the physicochemical meaning of each descriptor was examined. These results suggest that the ionic conductivity of each ionic liquid is governed not only as a liquid electrolyte but also as a solid electrolyte.

Data and QSPR study for viscosity of imidazolium-based ionic liquids

“…As indicated by the above definition ofˇ, the larger it is, the higher the dipole moment is; Tochigi and Yamamoto have observed that the larger the dipole moment of cation is, the higher the viscosity is [45]; thus, the viscosity increases with the enlargement ofˇ. This descriptor partially represents the effect of van der Waals interaction between cation and anion on the viscosity.…”

“…Once a QSPR correlation equation has been obtained, it is possible not only to use it to predict the same property for other structures not yet measured or even not yet prepared, but also to uncover the underlying relationship between macro-property and micro-structure. In fact, QSPR has been used to study the physicochemical properties of ILs, e.g., melting point [34][35][36][37], infinite dilution activity coefficient of organic solute in ILs [38,39], density [40,42,2], surface tension [41,42,2], conductivity [43][44][45][46][47], parachor [48], toxicity [49]. Only a few works were published for the QSPR study of ILs viscosity [43][44][45][46][47].…”

“…It was also indicated that a much more satisfying equation would be obtained if this equation was only for the same class of ILs (in their work, the equation was obtained from four classes of ILs, i.e., imidazolium, morpholinium, piperidinium, and pyridinium). Earlier, a type of correlation equation of polynomial expansion (PE) and BMLR were proposed by the research group of Tochigi [44][45][46][47] for a wide range of ILs, where a group of more coarse descriptors were adopted, such as molecular structure, electro-properties (dipole moment, lowest unoccupied molecular orbital level, and charges), and geometry characteristic (surface area, volume, and ovality). They found that dipole moment, cation size (area and volume), molecular ovality, and anion volume, have effects on viscosity.…”

Probing the electronic environment of binary and ternary ionic liquid mixtures by X-ray photoelectron spectroscopy

“…Ionic liquids, which are also known as low temperature molten salts, have found applications in both academic and industrial sources, attributing to their fascinating properties [1], especially negligible volatility and non-flammability. By varying the functionality of either the cation or the anion, it is potential to tune physico-chemical properties of ionic liquids [2][3][4][5].…”

Thermal Conductivity of Ionic Liquids: Measurement and Prediction

“…Alternatively, an approach predicting the structure of an IL exhibiting the required set of properties would be very useful [13]. For this purpose, quantitative prediction methods with a reasonable uncertainty must be developed, see, e.g., [14][15][16][17]. Yet, all prediction methods can only be as accurate as the experimental data used for the evaluation of their performance.…”