| Abstract: |
Organic synthesis has historically relied on volatile, toxic, and petroleum-derived solvents, a dependency that sits uneasily beside the chemical industry's stated environmental commitments. This paper reports an empirical evaluation of green solvent media deep eutectic solvents (DES), polyethylene glycol (PEG-400), water, and ionic liquids as replacements for conventional organic solvents in a set of representative organic transformations, including Knoevenagel-Michael cascades, dihydropyrimidinone synthesis, and multicomponent condensations. Reactions were performed under matched catalytic and temperature conditions across six solvent systems, and outcomes were quantified through isolated yield, reaction time, E-factor, atom economy, process mass intensity, and Eco Scale scoring. Across the reactions studied, DES-mediated protocols consistently outperformed conventional solvent routes, delivering yields between 91% and 96% against 78-87% for organic-solvent controls, while cutting reaction times by roughly six- to eight-fold and reducing E-factor values from the 18-32 range down to below 3. Recyclability trials over six cycles showed DES media retaining yields above 85%, only modestly ahead of ionic liquid systems. These findings, drawn together in the data analysis presented here, substantiate the paper's central claim: green solvents are not a compromise on reaction efficiency but, in several respects, an improvement on it. The discussion situates these results against prior green-chemistry literature and identifies where the present data diverge from earlier reports, particularly regarding DES viscosity effects on mass transfer. The paper concludes that green solvent media, when matched appropriately to reaction class, offer a viable and economically defensible pathway toward sustainable synthetic chemistry. |
