CO2 fluidising Deep Eutectic Solvents

Deep eutectic solvents (DES) are mixtures of two or more small molecules where strong intermolecular interactions lead to the formation of liquids at room temperatures. These solvents have wide applications from biomass extraction to syntheses, potentially replacing toxic and volatile organic solvents with liquids that can be made from more environmentally friendly components. The big drawback of DES is their high viscosities, which leads many researchers to add species such as water to fluidise them. However water is not compatible with all processes, so we have started a research program to explore fluidisation with CO2 instead. CO2 has no dipole moment so we expect quite different interactions with highly polar DES systems, to that of water. Here we propose to study the structure of a DES commonly used in biomass extractions choline chloride:oxalic acid: ethylene glycol, in the absence of CO2 and then at several different pressures of CO2 to determine how CO2 is incorporated into this liquid, and thus the mechanism for the observed viscosity reductions, and to link to biomass extraction efficiency in the fluidised DES.