QSPR Model to Predict the Speed of Sound of Ionic Liquids as a Function of Variable Temperature and Pressure

In this work, a u(T,P,I)-QSPR model utilizing the norm index (I) is developed to predict the speed of sound (u) of ionic liquids (ILs) over a wide range of pressures (P) and temperatures (T). During the modeling process, preprocessing is first performed against the collected data by using the equipartition rules for temperature and pressure. Temperature and pressure effects are introduced on the basis of cation, anion, and IL descriptors. The external and internal validations are used to evaluate the predictability and robustness of the u(T,P,I)-QSPR model. The statistical results show that the u(T,P,I)-QSPR model can accurately predict the u of ILs at variable temperature and pressure with R2test = 0.9952, Q2LOCO = 0.9917, and Q2LOAO = 0.9903. This facilitates the acquisition of property data (e.g., density and heat capacity) associated with u and the design of functional ILs.