ESTIMATIONS OF ENTHALPIES OF VAPORIZATION OF PURE COMPOUNDS AT DIFFERENT TEMPERATURES BY A CORRESPONDING-STATES GROUP-CONTRIBUTION METHOD

Two new equations (CSGC-HW1 and CSGC-HW2) for estimating enthalpies of vaporization at different temperatures with a corresponding-states gr oup-contribution method (CSGC) are proposed. Group-contribution parame ters for 76 groups were obtained by correlating the experimental entha lpies of vaporization at different temperatures (a total of 1647 data points) of 405 purl compounds including various alkanes, alkenes, cycl ohydrocarbons, aromatic and oxygenated hydrocarbons as well as compoun ds containing sulphur, nitrogen, and halogen. Accurate estimations of enthalpies of vaporization of pure compounds an given by the CSGC-HW1 equation, which requires the normal boiling point datum and the experi mental enthalpy of vaporization of the compound at the boiling point, Delta(v)H(b). If the experimental Delta(v)H(b) is not available, the C SGC-HW2 equation can be used to yield satisfactory estimates. (C) 1997 Elsevier Science B.V.