Phase behavior for the poly(2-methoxyethyl acrylate)+supercritical solvent+cosolvent mixture and CO2+2-methoxyethyl acrylate system at high pressure

Abstract

High pressures phase equilibrium data were presented for the CO2+2-MEA system at temperatures ranging from (313.2 to 393.2) K and pressures up to ca. 17.97MPa. The CO2+2-MEA system exhibited type-I phase behavior and was modeled using the Peng-Robinson equation of state. The phase behavior data were reported for poly(2- methoxyethyl acrylate) [P(2-MEA)] in supercritical CO2 and dimethyl ether (DME), as well as for the P(2-MEA)+2-methoxyethyl acrylate (2-MEA) (or DME) in CO2. The cloud-point data were measured for the P(2-MEA)+DME in supercritical CO2 at temperature range of (333–453) K and a pressure range of (8.79–199.14) MPa. The P(2-MEA) in supercritical CO2 was soluble to 453 K and pressure of 199MPa. The phase behavior for the P(2-MEA)+CO2+2-MEA mixture was measured in changes of the pressure-temperature (p, T) slope and with 2-MEA mass fraction of 0.0 wt%, 8.4 wt%, 17.1 wt%, 45.4 wt% and 65.0wt%. With 74.5 wt% 2-MEA to the P(2-MEA)+CO2 solution, the cloud-point curves took on the appearance of a typical lower critical solution temperature boundary, liquid+liquid transition and liquid+vapor transition. The location of the P(2-MEA)+CO2 cloud-point curve shifted to lower temperatures and pressures upon the addition of 2-MEA or DME.