A new method for assessment of glass transition temperature of ionic liquids from structure of their cations and anions without using any computer codes

This work introduces two simple correlations to assess the glass transition temperature of five different kinds of ionic liquids (ILs) including imidazolium, pyridinium, ammonium, sulfonium and triazolium without using any computer code. The first model is based only suitable combination of elemental composition of cations and anions divided by their molar masses. The second model improves the reliability of the first one by considering the contribution of some specific cations and anions. The reliability of two correlations will be compared with one the best reliable method, which is based on complex descriptors. For 139 ILs where the computed results of the representative model were available, the root mean square (rms) deviations of the first, the second and the representative models from the experimental data are 16.96, 7.60 and 9.28 K, respectively. Thus, the improved second correlation provides higher reliable results. The reliability of two correlations has also been checked for further 30 ILs where the values of the rms of the first and the second correlations are 12.50 and 9.92 K, respectively. In contrast to available methods, which are usually based on complex molecular descriptors and specific computer codes, the new method can easily calculate the glass transition temperatures of ILs including imidazolium, pyridinium, ammonium, sulfonium and triazolium.