Greener Media in Chemical Synthesis and Processing

Abstract

When two solids make a liquid: The phenomenon is reproduced every winter when salt is spread on icy roads. Upon mixing certain solids, a variety of low‐freezing and biodegradable liquids result (see picture). These eutectic mixtures offer a greener alternative to conventional ionic liquids and organic solvents.

Novel manganese(II)-based deep eutectic solvents: Synthesis and physical properties analysis

“…As the covalent bonds were formed, the crystal structure of MnCl 2 Á4H 2 O with acetamide or glycerol collapsed and this could leads towards the lower lattice energies in the DESs [27]. Where in such case, lesser energy is required to break the bonds, resulting in a depression of freezing point when the ion size is larger with smaller ion charges [28]. Thus, such DES with low lattice energy is the reason for its liquid phase existence at room temperature [27].…”

Solubility of carbon dioxide in a eutectic mixture of choline chloride and glycerol at moderate pressures

“…Like RTILs, deep eutectic solvents (i.e., 1 ChCl: 2 glycerol) exist as liquids over a large range of temperatures [21,27]. In this work, the vapour pressure of the DES was assumed to be negligibly small; thus, the gas phase is purely CO 2 .…”

“…They are a new class of ionic liquids that are made by mixing a substituted quaternary ammonium salt and a metal halide, amide or carboxylic acid, both of which may have high melting points, to form a eutectic mixture with a substantially lower melting point [19,20]. They are easy to prepare with high purity at relatively low cost, and most of them are biodegradable [21]. Being ionic liquids, DESs share many interesting characteristics with conventional RTILs such as negligible vapour pressure, wide liquid range, high thermal and chemical stabilities, non flammability, and other unusual solvent properties, which make them very promising candidates as green solvents for many chemical and industrial applications including CO 2 absorption [22][23][24].…”

High-pressure density measurements for choline chloride: Urea deep eutectic solvent and its aqueous mixtures at T= (298.15 to 323.15) K and up to 50 MPa

“…Thus, researchers are in the continued search for new and greener alternatives to these ILs that may overcome their limitations. Among such are the deep eutectic solvents (DES) which have been shown to have similar solvent properties to conventional ILs but are less expensive and many of them are biodegradable [15,16].…”