MEASUREMENT AND ESTIMATION OF VAPOR-PRESSURES OF DIMETHYL, DIETHYL, DIISOPROPYL AND DIBUTYL SUCCINATES AT REDUCED PRESSURE

Vapor pressures of dimethyl, diethyl, diisopropyl and dibutyl succinates were measured in the ranges of 0.6-100, 0.6-100, 0.4-100 and 0.5-15 kPa respectively. The percent root mean square deviations of pressure of the four succinates by fitting the Cragoe equation were 0.36, 0.34, 0.28 and 0.94 respectively. When, in addition to the information for the molecular structure of a substance of interest the value of the normal boiling point, T(b), was known, the Lee-Kesler and Gomez-Thodos equations with values of theta (= T(b)/T(c)) and P(c) obtained from the Joback method were separately applied to the estimation of vapor pressures for the succinates. The equations mentioned above were also extended successfully to the estimation of vapor pressures where only the value of any one datum point at the reduced pressure, in addition to knowledge of the molecular structure, was known.