Binary mixtures of dimethyl sulfoxide with methanol, ethylene glycol, and glycerol as solvent: Solvatochromism and chemical kinetics study

The understanding of solvent effects on chemical reaction requires precise knowledge of solute-solvent interactions. Since solute-solvent interactions are much more complex in mixed solvents, the study of chemical kinetics can be valuable because of the possibility of preferential solvation. In this work, binary mixture of methanol-DMSO, ethylene glycol-DMSO, and glycerol-DMSO were selected as solvent systems to determine solvatochromic polarity parameters and investigate the solute-solvent and solvent-solvent interactions. Results showed that the variation of parameters respect to solvent composition in these mixtures were compatible with those of in deep eutectic solvents-DMSO mixtures including ethylene glycol and glycerol. Aromatic nucleophilic substitution reaction of 1-fluoro-2,4-dinitrobenzene with piperidine was also investigated in the mentioned mixtures. Kinetic data showed that the reaction strongly follows the based-catalyzed mechanism in DMSO rich region. The partial catalytic and non-catalytic rate coefficients demonstrated reasonable correlations with solvatochromic parameters.