Agro‐Waste Extract Based Solvents: Emergence of Novel Green Solvent for the Design of Sustainable Processes in Catalysis and Organic Chemistry

Abstract

Water extract of agro-waste ash (AWEs) has emerged as an efficient non-conventional solvent for practicing green reactions in catalysis and organic chemistry. The recent advancements made in the field of agro-waste-derived reaction media have witnessed a major advancement in reactions like Suzuki-Miyaura, Sonogashira, Dakin, Henry, peptide synthesis and ipsohydroxylation. Traditionally, these reactions were conducted in conventional volatile organic solvents (VOCs) derived from non-renewable petroleum sources. During the course of these reactions AWEs displays distinct properties, such as, in situ base, homogeneous catalyst, nano reactor and reducing agent. This review summarizes the recent developments made in the application of AWEs in important reactions emphasizing on the key utilities and limitations in order to facilitate the further progress of this exciting area of research.

Extraction of Base from Eichhornia crassipes and Its Implication in Palladium‐Catalyzed Suzuki Cross‐Coupling Reaction

“…Very few works using agro‐waste surrogates have been reported . But, the scope and generality in regard to accessibility and abundance were quite periodic.…”

“…[41] Very few works using agro-waste surrogates have been reported. [42][43][44] But, the scope and generality in regard to accessibility and abundance were quite periodic. Thus, this aqueous extract in comparison to the mentioned literature well serves the world wide accessibility and terms of ecological footprints.…”

Palladium‐catalysed room‐temperature Suzuki–Miyaura coupling in water extract of pomegranate ash, a bio‐derived sustainable and renewable medium

“…Although recently some efficient methodologies have been developed for SMC by avoiding external base and ligands, there is still a demand to develop new synthetic protocols since unexpected results can be seen in SMC by a small change of reaction conditions like temperature, ligand, base, nature of substrates, solvent, etc . Typical trends in substrate selectivity and reactivity may be broken .…”

“…[41][42][43][44][45][46] Nevertheless, most of these are operated in harsh conditions [41] or require organic solvents [42,43] and additives such as surfactants [44,45] and polymers. [46] Although recently some efficient methodologies have been developed for SMC by avoiding external base and ligands, [47][48][49][50][51][52][53][54] there is still a demand to develop new synthetic protocols since unexpected results can be seen in SMC by a small change of reaction conditions like temperature, ligand, base, nature of substrates, solvent, etc. [55] Typical trends in substrate selectivity and reactivity may be broken.…”

A Green Protocol for the Synthesis of α‐Diazo‐β‐hydroxyesters and One‐Pot Conversion to β‐Keto‐Esters and Imidazo[1,2‐a]pyridine‐3‐carboxylates

“…Suzuki‐Miyaura and Sonogashira coupling, popular name reactions (for example Dakin and Henry reaction) and other organic synthesis such as peptide synthesis, azidation of aromatics and synthesis of 3‐carboxycoumarins have been successfully performed in this green reaction medium. Although WEB can be used alone, in some cases it has been mixed with organic solvents like ethanol and iso ‐propanol to increase the miscibility of reagents and starting materials so that the reactions furnish higher yields of the products . As is known from the literature that WEB contains carbonates of potassium and sodium metal along with their chloride salts and other trace elements, and for which it shows basic character and has been used as a base cum solvent for various organic transformations.…”