Vaporization enthalpy prediction of ionic liquids based on back-propagation artificial neural network

Vaporization enthalpy (Δ_vapH) is a fundamental thermodynamic property of ionic liquids (ILs). Accurate prediction of vaporization enthalpy relies on appropriate mathematical models grounded in precise experimental measurements. The quantitative structure-property relationship (QSPR) model, a key semi-empirical approach, could predict physicochemical properties based on the molecular structure of a substance. However, accurately predicting vaporization enthalpy and adequately describing the molecular structure of ILs remain significant challenges for this model. In this study, we used the cavity volume and charge density distribution area at specific intervals, derived from the conductor-like screening model for segment activity coefficient (COSMO-SAC) method, as molecular descriptors. Utilizing the developed descriptors, we constructed an improved QSPR model (Δ_vapH-ANN) to predict the vaporization enthalpy of ILs across a broad temperature range, employing the back-propagation artificial neural network (BP-ANN) algorithm. The dataset for our model consists of 3150 data points for 148 ILs within a temperature range of 298–631.86 K. Overall, the results show that the proposed Δ_vapH-ANN model, which treats ILs as “ion pairs”, can accurately predict the Δ_vapH of ILs across various temperatures.