Phase equilibria and cloud-point behavior for the poly(2-phenylethyl methacrylate) in supercritical CO2 with monomers as co-solvent

Abstract

This work focuses on the non-ideal phase equilibrium of methacrylate and acetate groups with weak polar. Phase behavior measurements were performed using a synthetic method by observing the bubble-point and cloud-point in a variable volume high-pressure view cell. The cloud-point and vapor-liquid experimental data at various temperatures and several pressures are obtained for two-component and three-component mixtures of supercritical CO2 + P(2-PEMA) [poly(2-phenylethyl methacrylate)] + co-solvents [2-phenylethyl methacrylate (2-PEMA), phenyl acetate (PAe), and 2-phenylethyl acetate (2-PEAe)] and CO2 + monomers (2-PEMA, PAe, and 2-PEAe) systems. The product data for the P(2-PEMA) + co-solvents mixture under supercritical CO2 are measured at up to 474.8 K and up to 200.86 MPa. The product sources for the CO2 + P(2-PEMA) + x wt.% 2-PEMA solutions were reported in changes of the p–T (pressure vs temperature) diagram, and with 2-PEMA weight fractions of (29.7, 35.1, 39.1, 44.5, and 52.2) wt.%. To obtain a two (vapor + liquid) region and three (liquid1 + liquid2 + vapor) region, the CO2 + P(2-PEMA) + 56.0 wt.% 2-PEMA, CO2 + P(2-PEMA) + 58.2 wt.% PAe, and CO2 + P(2-PEMA) + 57.6 wt.% 2-PEAe phase segregation curve bisects a supercritical liquid region → (liquid + vapor) region at ∼410 K and ∼23 MPa (2-PEMA), ∼365 K and ∼14 MPa (PAe), and ∼385 K and 18 MPa (2-PEAe), respectively.The equilibria data for the 2-PEMA, PAe, and 2-PEAe in CO2 are a significant in determining their suitability as organic solvent in various chemical processes. The equilibrium curves of the two-component solution for 2-PEMA, PAe, and 2-PEAe in compressed CO2 are examined using a synthetic method at (313.2 ≤ T ≤ 393.2) K and pressure of p ≤ 26.66 MPa. The three CO2 + 2-PEMA, CO2 + PAe, and CO2 + 2-PEAe two-component systems have mixture-critical loci that show the highest in the (p–T) space between the Tc of CO2 and 2-PEMA, PAe, or 2-PEAe. The CO2 + 2-PEMA, CO2 + PAe and CO2 + 2-PEAe mixtures display type-I curves. The product data for the CO2 + 2-PEMA, CO2 + PAe, and CO2 + 2-PEAe binary mixtures are correlated with the Peng–Robinson equation of state by a mixing rule with adjustable parameters of kij, and ηij.