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 CO 2 at diff erent operating

temperatures (313.2–393.2 K) and pressures (3.36–33.90 MPa). The fi ndings are expected to signifi cantly contribute

to the evolution of advanced materials and technologies in several industrial sectors. As temperature increases at constant

pressure, carbon dioxide (CO 2 ) 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 CO 2 , 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, confi rming

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 fi ve temperatures using the molecular IPs.

The calculated RSD% of the CO 2 + 3C2HM and CO 2 + 2NMEM systems were 4.70% and 4.91%, respectively, indicating

that the model values fi t 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 fi rst study to demonstrate the solubility of CO 2 + 3C2HM and

CO 2 + 2NMEM chemical mixtures, and it will be signifi cant for chemical industries.