Deep Eutectic Solvents as an Alternate to Other Harmful Solvents

Abstract

Solvents generally in liquid form, are used to dissolve, dilute, suspend any substances or extract other materials. More than one-third of the drugs listed in the various Pharmacopeias fall into the poorly water-soluble or water-insoluble categories. For more than 200 years, traditional solvents could be used as a solvent for substances that were insoluble in water. But the usage of these types of solvents should be decreased because these types of solvents are volatile, flammable, and often toxic. Also, the industrialist’s usages in different types of processes prove the risk for workers. In recent years, several solvents have been proposed to be the greener replacement for traditional solvents. Replacing hazardous chemicals with more environmentally friendly alternatives is a matter of current interest, in line with the philosophy of Green Chemistry. The use of nontraditional or nonconventional solvents such as supercritical fluids (SCFs) such as Carbon dioxide (CO2) and water, fluorous solvents, solventless reaction Ionic liquids (ILs) and their derivatives [polymeric ILs and magnetic ILs], and deep eutectic solvents (DESs) are alternatives for environmentally unfriendly traditional solvents. Among them, DES is a neoteric class of green solvents defined as a mixture of two or more compounds that are typically solid at room temperature, but when combined at a particular molar ratio, changes into a liquid at room temperature. It is assumed that eutectic mixtures show low volatility, have a broad liquid range, and are water-compatible, non-flammable, non-toxic, biocompatible, and eco-friendly. Eutectic solvents have been useful in several pharmaceutical fields, such as the increase of drug solubility, permeation, and absorption.

Deep Eutectic Solvents: Are They Safe?

“…This lack of predictive models is even more pronounced in the case of (eco)toxic behavior [56]. Regarding this topic, in general, DESs are considered to be nontoxic compounds [57]. Nevertheless, there are no systematic studies from the health and environmental toxicity points of view that confirm this point.…”

Tyrosinase Magnetic Cross-Linked Enzyme Aggregates: Biocatalytic Study in Deep Eutectic Solvent Aqueous Solutions

“…In an attempt to make biocatalysis even more environmentally friendly and sustainable, neoteric solvents, referred as “green” solvents, have gained in attractiveness since they have the potential to replace conventional ones (petrochemical and volatile organic compounds, VOCs) [ 4 , 5 , 6 , 7 ]. Among others, the class of “green solvents” consists of ionic liquids (ILs) and deep eutectic solvents (DESs), which share some benign physical characteristics, such as chemical and thermal stability and low vapor pressure [ 8 ].…”

Thymol+l-menthol eutectic mixtures: Thermophysical properties and possible applications as decontaminants

“…The latter are especially interesting due to their low toxicity. Other properties can be mentioned, according to the green chemistry principles, such as their nonflammability and nonvolatility and their easy, cheap and lack of waste preparation; thus, DESs are being used in various applications [9][10][11][12][13][14][15][16][17]. Among other factors, the depression in T m is a consequence of the capability of the components to form hydrogen bonds.…”

“…Its aim is focused on the removal of persistent chemicals, highlighting existing deficiencies in scientific knowledge. Eutectic mixtures with hydrophobic character have also been studied since 2015 as extraction solvents of persistent contaminants in aqueous medium [11,[27][28][29][30][31][32][33][34][35]. Among them, we highlight those containing thymol (T) and menthol (M) from now called TM system, because both components are considered generally recognized as safe (GRAS) by the Environmental Protection Agency (EPA).…”