Polyethylene glycol and solutions of polyethylene glycol as green reaction media

In this review, we examine the concept that aqueous biphasic reactive extraction (ABRE) can successfully integrate the solvent properties of polyethylene glycol (PEG) and its phase-transfer characteristics into a single efficient system which can additionally be manipulated to facilitate the separation of reactants and/or catalysts from products. We also suggest that the properties of these systems may recommend them as being relatively environmentally benign in comparison to the current use of organic solvents in extraction and in reactive extraction. In developing this concept, we review a number of the physical and chemical properties of PEG and aqueous solutions of PEG in the context of recent applications…