Phase Equilibria of Binary Mixtures of 3-Chloro-2-Hydroxypropyl Methacrylate and 2-N-Morpholinoethyl Methacrylate in Supercritical Carbon Dioxide

This study presents exceptional perception into the phase transition behavior of binary mixtures containing 3-chloro-2-hydroxypropyl methacrylate (3C2HM) or 2-N-morpholinoethyl methacrylate (2NMEM) in supercritical CO₂ at different operating temperatures (313.2–393.2 K) and pressures (3.36–33.90 MPa). The findings are expected to significantly contribute to the evolution of advanced materials and technologies in several industrial sectors. As temperature increases at constant pressure, carbon dioxide (CO₂) solubility in the monomer aqueous phase decreases. However, the solvability of the binary systems improved with temperature and mole fraction at steady pressure. The 2NMEM component exhibited higher polarizability and lower surface tension than the 3C2HM monomer, making it less soluble in CO₂, which is a nonpolar compound. The solution phase of the binary systems exhibited Type I phase behavior, and the phase diagrams were nearly identical. The experimental solubility data were adequately correlated with the Peng–Robinson equation of state with the aid of molecular interaction parameters (IPs) which was evaluated at 353.2 K. The optimized molecular IPs were nearly zero, confirming that both binary systems were nearly ideal mixture systems as the temperature increased. The model precision was evaluated by calculating the percentage of root-mean-square deviation (RSD%) at five temperatures using the molecular IPs. The calculated RSD% of the CO₂ + 3C2HM and CO₂ + 2NMEM systems were 4.70% and 4.91%, respectively, indicating that the model values fit reasonably well. Therefore, the predicted phase behavior agrees well with the experimental phase transitions of both systems. The characteristics of the critical solution curve were simulated to realise the interactions and transition behavior of the studied binary systems. This is the first study to demonstrate the solubility of CO₂ + 3C2HM and CO₂ + 2NMEM chemical mixtures, and it will be significant for chemical industries.