Vapor–Liquid Equilibrium of Ethanol + Sulfur Dioxide and Ethanol + Water + Sulfur Dioxide at Six Temperatures

Binary isothermal vapor–liquid equilibrium (VLE) of ethanol and sulfur dioxide (SO2) at six temperatures (303–353 K) was measured. The systems were modeled using the non-random two-liquid (NRTL)–Hayden–O’Connell (HOC) model. The NRTL parameters were optimized using Barker’s data reduction method. Ternary isothermal VLE of ethanol, water, and SO2 at six temperatures (303–353 K) was measured. The binary isothermal VLE of SO2 and water in the dilute range of SO2 and liquid–liquid equilibrium (LLE) were found in the literature, and the NRTL parameters were optimized for the system. In addition, the isothermal VLE for ethanol and water found in the literature was used to evaluate the default parameters of Aspen Plus and found accurate. The binary LLE of water and SO2 was essential in modeling the phenomenologically proper phase behavior. With the optimized parameters, it was possible to calculate the LLE and vapor–liquid–liquid equilibrium (VLLE) regions of the ternary system. The comparison of the model and measurements to the literature were presented, and very good accuracy was found

Vapor–Liquid Equilibria, Excess Enthalpy, and Density of Aqueous γ‑Valerolactone Solutions.

Thermodynamic measurements were made for the binary mixture of water + γ-valerolactone (GVL) and for pure GVL to facilitate the development of the technology of lignin removal from lignocellulosic biomass (Fang, W.; Sixta, H. Advanced Biorefinery based on the Fractionation of Biomass in γ - Valerolactone and Water. ChemSusChem 2015, 8, 73−76). The density and vapor pressure of pure GVL as a function of temperature were measured and correlated for a wide range of the temperatures and pressures. Isothermal vapor–liquid equilibrium (VLE) data of the binary mixture of water + GVL were measured at 350.2 K with a static total pressure apparatus. Absence of an azeotrope was confirmed by circulation still measurements with diluted GVL solutions. Excess molar enthalpy (<i>h</i>^E) of the mixture for the whole range of mole fractions including infinite dilution was measured using a SETARAM C80 calorimeter equipped with a flow mixing cell at 322.6 and 303.2 K. The VLE and <i>h</i>^E data were used for the optimization of UNIQUAC and NRTL activity coefficient model parameters. The experimental results are compared herein with those predicted by COSMO-RS and UNIFAC-Dortmund models. The water + GVL binary mixture shows positive deviation from Raoult’s law