Prediction of the heat capacity of ionic liquids using the mass connectivity index and a group contribution method

A simple and accurate group contribution method to estimate the heat capacity of ionic liquids is presented. The method considers groups previously defined for a successful method used to estimate critical properties of ionic liquids. Additionally a structural parameter known as mass connectivity index recently defined by the authors has been incorporated to define the model equation. To better define the values of the groups, heat capacity data at 298 K for 126 organic substances were used with the 469 heat capacity data for 32 ionic liquids. The results were compared with experimental data and with values reported by other available estimation methods. Results show that the new group contribution method gives low deviations and can be used with confidence in thermodynamic and engineering calculations.

► An accurate group contribution method to estimate the heat capacity of ionic liquids is presented. ► The method considers groups previously defined for estimating critical properties of ionic liquids. ► A structural parameter known as mass connectivity index is included in the model equation. ► Heat capacity data (469 points) for 32 ionic liquids were used to develop the model. ► The method gives acceptable predictions of heat capacities of ionic liquids.