Relationship between the heat capacity change on vaporization of normal and branched alkanes and the vaporization enthalpy and its prediction as a function of temperature

In the present work, the relationship between the difference of the heat capacities of the liquid and ideal gas and intermolecular interaction energy in alkanes was investigated. The vaporization enthalpy at 298.15 K was considered as a measure of intermolecular interaction energy. For 40 alkanes linear correlation between the above quantities was revealed with a root mean square deviation (RMS) of 3.5 J.K-1.mol(-1), regardless of branching. Using this correlation and group-contribution-derived vaporization enthalpies at 298.15 K, the vaporization enthalpies of 192 alkanes at elevated temperatures were calculated and compared with 317 literature values. RMS equaled 1.7 kJ.mol(-1), being competitive with experimental techniques. (C) 2021 Elsevier Ltd.

Automated summary

This study investigates the relationship between the heat capacities of liquid and ideal gas in alkanes, and the intermolecular interaction energy. A linear correlation was found for 40 alkanes, regardless of branching, with competitive results compared to experimental techniques.