Prediction of boiling points and melting points of aromatic compounds
- Univ. of Arizona, Tucson, AZ (United States). Dept. of Pharmaceutical Sciences
Two transition temperatures that are most frequently measured are boiling point and melting point. These properties are environmentally of importance because they are two main factors that control the vapor pressure and solubility of organic compounds. Therefore, the ability to predict both transition temperatures would aid in the estimation of other environmentally important physico-chemical properties. In this study, simple methods are proposed to estimate the boiling points and melting points from chemical structure. The proposed predictive methods are derived from a generally known thermodynamic equation: T{sub tr} = {Delta}H{sub tr}/{Delta}S{sub tr}. The transition temperatures are determined by the estimation of both the enthalpy and the entropy of transition. The enthalpies of boiling and melting are both estimated as additive constitutive properties. The entropy of boiling of aromatic compounds is assumed to be constant as described by Trouton`s rule, while the entropy of melting is not constant. It depends on non-additive non-constitutive molecular property, rotational symmetry ({sigma}).
- OSTI ID:
- 40015
- Report Number(s):
- CONF-9410273--
- Country of Publication:
- United States
- Language:
- English
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