Vapor pressures of 12 alkylcyclohexanes, cyclopentane, butylcyclopentane and trans-decahydronaphthalene down to 0.5 Pa. Experimental results, correlation and prediction by an equation of state

Abstract

Several improvements of the static device developed by the authors for measuring low vapor pressures are described: 1. a installation of a supplementary pressure gauge allowing the extension of the measurement range up to 200 kPa 2. b modification of the measurement cell in order to have a good degassing of the compounds (important step in low vapor pressure measurements). The apparatus was used to measure vapor pressure (0.5 Pa to 200 kPa) of 12 alkylcyclohexanes, cyclopentane, butylcyclopentane and trans-decahydronaphthalene. The experimental results correlated using Wagner's equation are in good agreement with the available literature data. Experimental vapor pressures were then represented and predicted satisfactorily with a modified version of the Peng-Robinson equation of state in which the different parameters were expressed in terms of a group contribution method.