Estimating solid-liquid phase change enthalpies and entropies

A group additivity method based on molecular structure is described that can be used to estimate solid-liquid total phase change entropy (Delta(0)(Tfus)S(tpce)) and enthalpy (Delta(0)(Tfus)H(tpce)) 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 Delta(0)(Tfus)S(tpce) and Delta(0)(Tfus)H(tpce), respectively. For the 260 test compounds, standard deviations of +/- 13.0 J.mol(-1).K-1 (Delta(0)(Tfus)S(tpce)) and +/-4.88 kJ mol(-1) (Delta(0)(Tfus)H(tpce)) 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. (C) 1999 American Institute of Physics and American Chemical Society. [S0047-2689(99)00106-3].