Deep eutectic solvent as an operative media on structure‐reactivity relationships

Abstract

AbstractDeep eutectic solvents seem to be environmentally friendly solvents, particularly because they are prepared easily and have very low‐vapor pressures under ambient conditions. They are suitable candidates as green solvents for reaction media with special properties. To present this behavior, substitution reactions of some para‐ and meta‐substituted anilines with 1‐fluoro‐2,4‐dinitrobenzene have been spectrophotometrically investigated in varying mole fractions of ethaline as a deep eutectic solvent in dimethyl sulfoxide (DMSO). The measured rate coefficients of the reaction demonstrated a noticeable variation with the increasing mole fraction of ethaline in ethaline‐DMSO mixtures. The linear free energy relationship (LFER) of second‐order rate coefficients based on Hammett's substituent constants demonstrates a reasonably linear straight line with a negative slope in different mole fractions of ethaline‐DMSO mixtures. Another LFER investigation based on the polarity parameters of the media showed a good agreement with hydrogen bond donor and acceptor abilities of the solvent. Non‐LFER assay according to the preferential solvation model confirmed differences between the microsphere solvation of the solute molecules and the bulk composition of the solvents.