CO2-switchable Materials: Solvents, Surfactants, Solutes and Solids
Chapter 6: CO2-switchable Hydrophilicity Solvents
Published:11 Sep 2020
Special Collection: 2020 ebook collection , ECCC Environmental eBooks 1968-2022Series: Green Chemistry
CO2-switchable Materials: Solvents, Surfactants, Solutes and Solids, The Royal Society of Chemistry, 2020, ch. 6, pp. 96-117.
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A switchable-hydrophilicity solvent (SHS) is a liquid that can be changed between a hydrophilic state that is water-miscible and a hydrophobic state that is water-immiscible at a specific concentration and temperature. If an SHS is used as a solvent for a reaction or extraction, then thanks to the switchability the solvent can be removed from products, and subsequently recycled, without any distillation step. Because distillation is not required, SHS with very low volatility can be used. As a result of the low volatility and the avoidance of distillation, energy savings can be realized and impacts related to volatility, like flammability, smog formation, and inhalation risks, can be minimized. Applications include preparative extractions, analytical separations, and post-reaction separations. SHS are not, however, without their own hazards, so they need to be selected carefully to combine performance with minimum impact.