(204g) Ternary Phase Behavior Of Liquid Polyethylene Glycol With Carbon Dioxide And Common Organic Solvents


Polyethylene glycol (PEG) has recently been investigated as a novel, sustainable solvent. At low molecular weights (200-600), it is non-toxic and has low volatility, making it a green alternative to organic solvents. We are using PEG in combination with carbon dioxide to facilitate homogenous reactions and heterogeneous separations, allowing for improved reaction rates, catalyst recycle, and easy product recovery. We can achieve this by mixing PEG with common organic solvents, which creates a homogenous phase for reaction. By applying carbon dioxide pressure, we can split this mixture into two phases, allowing for catalyst recycle in the PEG phase and product recovery in the organic solvent phase. In order to develop these systems, it is necessary to understand the thermodynamics. Hence, our work focuses on the phase behavior of PEG 400 and carbon dioxide with several organic solvents, including 1,4-dioxane, acetonitrile, and tetrahydrofuran. We determined the vapor-liquid-liquid equilibrium with a variable-volume view cell at 25 and 40ºC and pressures ranging from 45 to 60 bar. We also compare the experimental data with several theoretical models. The results illustrate that these PEG systems are viable alternatives for enabling homogeneous reaction and heterogeneous separation.