Vapor–Liquid Interfacial Properties of the Systems (Toluene + CO₂) and (Toluene + N₂): Experiments, Molecular Simulation, and Density Gradient Theory

Abstract

Vapor−liquid interfacial properties of the binary systems (toluene + CO 2 ) and (toluene + N 2 ), as well as for the three pure components toluene, CO 2 , and N 2 , were studied using experimental and theoretical methods. Data on the surface tension and the relative adsorption were obtained from pendant drop experiments as well as from molecular dynamics (MD) simulations and density gradient theory (DGT) + perturbed-chain polar statistical associating fluid theory (PCP-SAFT). The experiments were carried out at temperatures between 303.15 and 373.15 K and pressures up to 5.7 MPa. MD and DGT calculations were carried out at 283.15, 303.15, 323.15, and 343.15 K in the entire composition range. MD and DGT were also used for studying the enrichment of the low-boiling component and the thickness of the interface. Furthermore, the vapor−liquid equilibrium (VLE) bulk phase properties were computed by MD and PCP-SAFT and compared to experimental data from the literature. The data from the different methods were found to be in good agreement throughout. The comparison of the results for the two studied mixtures provides insights into the link between phase behavior, interfacial properties, and molecular interactions.