Fluid phase equilibria in asymmetric model systems. Part II: CO2 + 2,2,4,4,6,8,8-heptamethylnonane

Abstract

The experimental phase behavior of carbon dioxide and 2,2,4,4,6,8,8-heptamethylnonane mixtures was studied at T = (293.15–378.15) K and at pressures of up to 20 MPa. The carbon dioxide content varied from 20.0 to 95.0 mol%, and phase transitions were determined using the synthetic variable volume method along 11 different isopleths. These results suggest that the system studied could present a type I or II phase behavior according to the classification of van Konynenburg and Scott for binary mixtures. Experimental data were successfully described by the Peng-Robinson equation of state using temperature-dependent binary interaction parameters.