Vaporization enthalpy, long-term evaporation and evaporation mechanism of polyethylene glycol-based deep eutectic solvents†
We for the first time have found that PEG-based DESs could volatilize at room temperature and atmospheric pressure. The mass loss from long-term evaporation of PEG-based DESs at 298.15 K for 1000 min could reach as high as 30.5% mass loss, ca. 6 times that of short-term evaporation (5.1% mass loss). Generally, the vaporization enthalpy of PEG-based DESs is found to lie between that of common organic solvents and that of ionic liquids, while some PEG-based DESs could be more volatile than common organic solvents. The evaporation of PEG-based DESs could be ascribed to their volatile constituents; however, the evaporation rate of each constituent is found to be very different. This is the first discovery of the higher volatility of PEG-based DESs at room temperature and atmospheric pressure.