Myths and Realities about Existing Methods for Calculating the Melting Temperatures of Ionic Liquids

The several methods presented in the literature during the past few years to estimate the melting temperatures of ionic liquids and the alleged accuracy of the methods mentioned by several authors are analyzed and discussed in this work. Because of the importance of the melting temperatures for the development and applications of ionic liquids, several models have been proposed in the literature. Methods based on computational chemistry, group contribution, artificial neural networks, and chemical homology are considered in this analysis, and results from the different approaches are discussed. The general conclusion about these advances is that it is a myth that, with the present experimental data and knowledge we have of ionic liquids, we can obtain accurate and generalized correlations and estimation methods for determining the melting temperatures of ionic liquids. Ideas about what is needed and on how to proceed in the future are presented.