Experimental and modelling study of the phase behavior of (methyl propanoate + carbon dioxide) at temperatures between (298.15 and 423.15) K and pressures up to 20 MPa

Abstract

In this work, we report phase equilibrium measurements on the system (methyl propanoate + carbon dioxide) carried out with a high-pressure quasi-static-analytical apparatus. The measurements were made along six isotherms at temperatures from (298.15 to 423.15) K and at pressures up to the critical pressure at each temperature. Vapor-liquid equilibrium (VLE) data obtained for the mixture have been compared with the predictions of the Statistical Associating Fluid Theory coupled with the Mie potential and a group-contribution approach for the functional group interaction parameters (SAFT-γ Mie). The group interaction parameters in SAFT-γ Mie for the COO–CO2 interaction have been revised in this work by fitting to our experimental VLE data. After tuning, the SAFT model was found to be in good agreement with the measured data for both the liquid and vapor phases. Additionally, the data were compared with the predictions of the Peng-Robinson equation of state (PR-EoS) with one-fluid mixing rules and a temperature-independent binary parameter. This model fitted the VLE data well, except in the critical region. The present work is expected to contribute to optimization of biodiesel production processes.