Isobaric Vapor–Liquid Equilibria of Binary and Multicomponent Organic Carbonate Mixtures (DMC, EMC, DEC, EC, and PC) at 101.3, 25.0, and 5.0 kPa

Abstract Isobaric vapor–liquid equilibrium (VLE) data were determined for all ten binary combinations of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate (PC), and ethylene carbonate (EC) at 101.3 and 25.0 kPa using a dynamic recirculating still. For the PC–EC system, measurements were conducted at 25.0 and 5.0 kPa to prevent thermal degradation of EC observed at temperatures above 483–493 K. Representative ternary systems and selected quinary mixtures were additionally investigated at 101.3 and 25.0 kPa. Vapor pressure curves of all substances were determined and correlated, together with statistically screened literature data, using the Antoine equation. VLE was modeled assuming ideal behavior using Raoult’s law, and nonideal liquid-phase behavior using NRTL and UNIQUAC excess Gibbs energy models. UNIQUAC parameters were identified either separately for each binary system (UNIQUAC-sep), following common practice, or by a proposed global fitting approach (UNIQUAC-gl), which reduces the number of fitting parameters. Data reliability was evaluated through uncertainty propagation analysis, while beforehand thermodynamic consistency was assessed qualitatively from activity coefficient plots and quantitatively using the Herington test. The successful description of ternary and quinary systems confirmed the models’ applicability beyond the binary parameter identification and enabled the calculation of residue curve maps.