Solvents from nature

Abstract

In this perspective, a personal journey from solvent to solvent is presented to demonstrate how environmentally friendly solvents can be part of the solution of various chemical challenges. Solvents are important components of Nature to provide one or more liquid phases for chemical reactions and processes. While some solvents are available from Nature even in large quantities, most of the solvents are man-made. Historically, solvents were developed and/or selected to help the chemical or physical objectives of the user(s) only. With the increasing importance of local and global health and environmental issues, including the introduction of green chemistry and the molecular approach for pollution prevention, the potential impacts of solvents became important selection tools. One of the key principles of green chemistry is the elimination of solvents in chemical processes or the replacement of hazardous solvents with environmentally benign solvents. The development of solvent-free alternative processes is the best solution, especially when either one of the substrates or the product is a liquid and can be used as the solvent of the reaction. However, if solvents are crucial to a process we should select from solvents that will have no or limited impact on health and the environment.

Eco-solvents – cluster-formation, surfactantless microemulsions and facilitated hydrotropy

“…g-Valerolactone (GVL) is another sugar-based eco-solvent that has attracted attention recently. [10][11][12][13][14] It can be produced at yields higher than 95% by the hydrogenation of levulinic acid 15,16 which can be derived from biomass. 17, 18 Horváth et al…”

Definition of green synthetic tools based on safer reaction media, heterogeneous catalysis, and flow technology

“…Several promising directions have been undertaken by the green chemistry community and excellent results have been achieved using non-conventional solvents as water [10][11][12][13][14][15], supercritical CO 2 [16][17][18][19], ionic liquids [20][21][22] as well as biomass-derived solvents that feature the obvious advantage of deriving from renewable resources [23][24][25]. In the latter case, additional considerations should be made by evaluating the synthetic route used for their preparation but can be certainly considered as "greener" and promising alternatives to fossil based solvents.…”

Glycerol as a recyclable solvent in a microwave-assisted synthesis of disulfides

“…Spectra were recorded in CDCl 3 solutions. Chemical shifts are reported in parts per million, referenced to the solvent peak of CDCl 3 . Column chromatography was performed using Merck Silica Gel (230Á400 mesh) following the standard methods.…”