Physical Properties and CO2 Absorption Capacity of Propylene Carbonate + Poly(propylene glycol) Monobutyl Ether Systems

The mixtures of propylene carbonate (PC) (1) + poly(propylene glycol) monobutyl ether with a molecular weight of 340 (PPGME340) (2) were studied as physical absorbents for CO2 absorption with different mass fractions (w1 = 0.0000, 0.2501, 0.5002, 0.7495, and 1.0000). The physical properties including densities and kinematic viscosities of these absorbents were determined and regressed by linear equation and Vogel–Fulcher–Tammann equation. CO2 absorption capacities of the absorbents under pressures up to 1300 kPa and at temperatures from 298.15 to 303.15 K were determined by the isothermal synthesis device and fitted by the extended Antoine equation. Adding PC into PPGME340 will result in a slight increase of density, dramatic decrease of kinematic viscosity, and moderate decrease of CO2 absorption capacity based on per mole absorbent. Compared with common solvents in industrial plants, PPGME340-contained absorbents show relatively high absorption capacity and kinematic viscosity. In addition, absorbent PC + PPGME340 with a mass fraction of w1 = 0.2501 shows relatively high CO2 absorption capacity and moderate kinematic viscosity, suggesting its better potential for the industrial application than pure PPGME340.