Solubility in CO2 and swelling studies by in situIR spectroscopy of vegetable-based epoxidized oils as polyurethane precursors

The phase behaviour of carbon dioxide/vegetable based epoxidized oil (VBEO) mixtures has been investigated at three different temperatures (40, 70 and 100 °C) and pressures ranging between 0.1 and 20 MPa. The measurements have been performed using an efficient in situFTIR method that allowed us to determine the variation of the concentration of each component in the two phases (CO2 rich phase and VBEO rich phase) as a function of temperature and pressure. Several epoxidized mono-, di- and tri-glyceride derivatives have been tested. The solubility of these epoxidized oils in the CO2 rich phase and the swelling of the VBEO rich phase resulting from the CO2 sorption have been investigated. From these concentration measurements, we could establish the pressure–composition phase diagrams of these VBEO/CO2 binary mixtures. The three studied monoglyceride derivatives were found to be more soluble in CO2 and more easily swelled by CO2 in comparison to the di- and tri-glyceride derivatives. Nevertheless, it was found that a significant amount of CO2 was incorporated in all these VBEO at relatively moderate pressures. Thus, we expect these VBEO to be good candidates for performing carbonation reaction to generate in good yields vegetable-based cyclic carbonates as polyurethane precursors.