GROUP-CONTRIBUTION METHODS FOR PREDICTING THE MELTING-POINTS AND BOILING POINTS OF AROMATIC-COMPOUNDS

Simple methods are proposed to estimate the boiling points and the mel ting points of aromatic compounds from chemical structure. The transit ion temperatures are, determined by the estimation of both the enthalp y and the entropy of transition. The enthalpies of boiling and melting are both estimated as additive constitutive properties. The entropy o f boiling is assumed to be constant as described by Trouton's rule, wh ile the entropy of melting is estimated using a modification of Walden 's rule. The latter utilizes the nonadditive nonconstitutive molecular property, rotational symmetry.