High-pressure phase equilibrium of the binary systems CO2 + 355-TMHA and CO2 + 335-TMCHMA

• Published in: New journal of chemistry 2023-02, Vol.47 (8), p.4043-4051
• Main Authors: Dhamodharan, Duraisami, Chang-Woo, Lee, Hun-Soo Byun
• Format: Article
• Language: English
• Subjects: Binary systems; Carbon dioxide; Equations of state; High pressure; Miscibility; Mixtures; Phase equilibria; Temperature; Thermodynamics
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d2nj05825a

The thermodynamic behaviors of the two-phase systems of 3,5,5-trimethylhexyl acrylate (355-TMHA) and 3,3,5-trimethylcyclohexyl methacrylate (335-TMCHMA) in high-pressure CO2 are reported. The thermodynamic data were determined with the aid of a synthetic approach at temperature (T) = (313.2–393.2 K) and pressure (p) = (3.84–20.80 MPa). The acquired findings revealed that the miscibility of CO2 was observed to raise monotonically and the augmented of model Ts and mole fraction of (355-TMHA and 335-TMCHMA) in two-component (solvent + solute) mixtures. The miscibility curves of 355-TMHA and 335-TMCHMA in the 355-TMHA + Sc-CO2 and 335-TMCHMA + Sc-CO2 systems increased with the temperature at a fixed pressure. The 355-TMHA + Sc-CO2 and 335-TMCHMA + Sc-CO2 systems exhibited type-I phase behavior. Besides, the lab-based investigational solubility was adequately compared with the value obtained using the Peng–Robinson equation of state (P–R E–S). Both the model mixtures (355-TMHA + Sc-CO2 and 335-TMCHMA + Sc-CO2) did not reveal 3 phases (liquid + vapor + liquid) at any of the five analyzed temperatures. The P–R E–S comparatively provided the phase behavior (PB) of the (355-TMHA + Sc-CO2 and 335-TMCHMA + Sc-CO2) models utilizing two T-independent mixture interaction factors. The mixture critical curves (MCC) obtained using the computational data and lab-based results had a relatively good match when the two adjustable factors of the P–R E–S were applied. The root means square deviation (RMSD) percentage (%) for the 355-TMHA + Sc-CO2 [κij = 0.040, ηij = −0.040] and 335-TMCHMA + Sc-CO2 [κij = 0.035, ηij = −0.040] systems ascertained at 353.2 K utilizing the two factors were 6.67% and 7.57%, correspondingly. Then, the RMSD (%) of the 335-TMCHMA + Sc-CO2 system predicted using the adjusted values at every temperature was noted as 4.56%.