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The Estimation of Melting Points and Fusion Enthalpies Using Experimental Solubilities, Estimated Total Phase Change Entropies, and Mobile Order and Disorder Theory

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journal contribution
posted on 03.03.2002, 00:00 by James S. Chickos, Gary Nichols, Paul Ruelle
Melting points and fusion enthalpies are predicted for a series of 81 compounds by combining experimental solubilities in a variety of solvents and analyzed according to the theory of mobile order and disorder (MOD) and using the total phase change entropy estimated by a group additivity method. The error associated in predicting melting points is dependent on the magnitude of the temperature predicted. An error of ± 12 K (± 1 σ) was obtained for compounds melting between ambient temperature and 350 K (24 entries). This error increased to ± 23 K when the temperature range was expanded to 400 K (46 entries) and ± 39 K for the temperature range 298−555 K (79 entries). Fusion enthalpies were predicted within ± 2σ of the experimental values (± 6.4 kJ mol-1) for 79 entries. The uncertainty in the fusion enthalpy did not appear dependent on the magnitude of the melting point. Two outliers, adamantane and camphor, have significant phase transitions that occur below room temperature. Estimates of melting temperature and fusion enthalpy for these compounds were characterized by significantly larger errors.