Phase behavior of the poly(vinyl pyrrolidone) + N-vinyl-2-pyrrolidone + carbon dioxide system

We measured pressure–composition (P–x) isotherms for binary mixture of carbon dioxide (CO2) + N-vinyl-2-pyrrolidone (NVP) at temperature from 324 to 355 K and pressure up to 19.0 MPa. Phase behavior of these binary experimental data was modeled with Peng–Robinson equation of state with two adjustable parameters. And we measured cloud point pressures of carbon dioxide (CO2) + poly(vinyl pyrrolidone) (PVP) system. But PVP was not dissolved in pure CO2 up to 480 K and 290 MPa. Also we measured cloud point pressures for the ternary system of poly(vinyl pyrrolidone) (PVP) + N-vinyl-2-pyrrolidone (NVP) + carbon dioxide (CO2) using a variable volume view cell as a function of molecular weight and NVP contents at temperature up to 450 K and pressure up to 220 MPa.