Estimating Solid–Liquid Phase Change Enthalpies and Entropies Available to Purchase

A group additivity method based on molecular structure is described that can be used to estimate solid–liquid total phase change entropy $(Δ0TfusStpce)$ and enthalpy $(Δ0TfusHtpce)$ of organic molecules. The estimation of these phase changes is described and numerous examples are provided to guide the user in evaluating these properties for a broad range of organic structures. A total of 1858 compounds were used in deriving the group values and these values are tested on a database of 260 additional compounds. The absolute average and relative errors between experimental and calculated values for these 1858 compounds are 9.9 J⋅mol⁻¹⋅K⁻¹ and 3.52 kJ⋅mol⁻¹, and 0.154 and 0.17 for $Δ0TfusStpce$ and $Δ0TfusHtpce,$ respectively. For the 260 test compounds, standard deviations of $±13.0 J⋅mol−1⋅K−1(Δ0TfusStpce)$ and $±4.88 kJ mol−1(Δ0TfusHtpce)$ between experimental and calculated values were obtained. Estimations are provided for both databases. Fusion enthalpies for some additional compounds not included in the statistics are also included in the tabulation.