Phase Equilibrium Measurements and Thermodynamic Modeling of the Systems (CO₂ + Ethyl Levulinate) and (CO₂ + Levulinic Acid)

Abstract

This work reports phase equilibrium measurements and thermodynamic modeling of the binary systems (CO 2 + ethyl levulinate) and (CO 2 + levulinic acid). Each composition was carried out in a high-pressure variablevolume view cell at temperatures ranging from 303.15 to 353.15 K and with CO 2 mole fraction ranging from 0.4002 to 0.9751 for the system (CO 2 + ethyl levulinate) and from 0.4083 to 0.9930 for the system (CO 2 + levulinic acid). Under these conditions, only vapor−liquid phase transitions were observed. The experimental data were modeled with the Peng−Robinson cubic equation of state with the Boston− Mathias alpha function (PR-BM) and using the van der Waals quadratic mixing rule. The results showed that the experimental data of the system (CO 2 + ethyl levulinate) were adequately represented by the thermodynamic model with a unique set of binary interaction parameters, which were fitted from all isotherms. Whereas the experimental data of the system (CO 2 + levulinic acid) were only adequately represented with temperature-dependent binary interaction parameters.

Phase-Equilibrium Measurements and Thermodynamic Modeling of CO2 + Geraniol, CO2 + Geraniol + Acetic Acid, and CO2 + Geraniol + Ethyl Acetate

“…The general basis of the experimental apparatus and procedure utilized in the present work have been formerly reported by our research group. ,− The schematic diagram of the experimental apparatus is depicted in Figure .…”

“…The visual observations were achieved through two sapphire windows, one on the side and another at the front of the cell. For each system composition, the procedure was the same as described by Veiga et al and Giacomin et al , The procedure starts by flushing the cell with CO 2 gas (288.2 K and 6.0 MPa) to remove any residual air. After, the cell is loaded with the respective amount of liquid solute (geraniol, a mixture of geraniol + acetic acid or geraniol + ethyl acetate), previously gravimetrically measured (RADWAG, model AS220/C/2, ±0.0001 g uncertainty).…”

“…The thermodynamic modeling used in this work followed a previously reported , procedure using the Peng–Robinson (PR) equation of state with the conventional quadratic van der Waals (vdW2) mixing rule, as shown in eqs –. PR EoS was chosen due to its simplicity and reasonable accuracy for the systems present in this paper.…”

“…Although research in the synthesis of geranyl acetate has been reported recently, there is a lack of thermodynamic data regarding the phase equilibrium of the reaction substrates and CO 2 . As the interactions between all components available in the system is an essential matter for designing, modeling, and optimization of processes, mainly due to the presence of supercritical fluid, knowledge of the correct phase-equilibrium data and thermodynamic calculations is a crucial issue of the process design …”

Phase equilibrium measurements and thermodynamic modeling of {CO2 + diethyl succinate + cosolvent} systems

“…The experimental apparatus and procedure used in this work were presented and described in previous publications [13][14][15][16][17]. Briefly, the experimental data measurements were performed in a high-pressure variable-volume view cell containing a movable piston, which allows the pressure control inside the cell.…”