The vapour pressures above the normal boiling point and the critical pressures of some aromatic hydrocarbons

Abstract

The vapour pressures of benzene, toluene, ethylbenzene, and the three xylenes have been measured between their normal boiling points and their critical temperatures by both dynamic and static methods. Trial was made of several equations proposed for the representation of the vapour pressure–temperature relationship over a wide temperature range, and the constants of best fit for the two most satisfactory equations were found for the six substances. Critical pressures only were determined for propyl-, isopropyl-, 1,2,3-trimethyl-, 1,2,4-trimethyl-, 1,3,5-trimethyl, butyl-, and 1,4-diethyl-benzene and naphthalene. The results were correlated and methods are proposed for the estimation of vapour pressures (including critical pressures) of compounds for which experimental data are lacking.