Investigation of Solvent Effects on the Reaction of 1-Fluoro-2,4-Dinitrobenzene with Aniline in Molecular-Molecular and Ionic Liquid–Molecular Solvent Mixtures

Abstract

The solvent effects on the reaction of 1-fluoro-2,4-dinitrobenzene with aniline was studied in various compositions of molecular-molecular solvent mixtures and molecular solvent-2-hydroxyethylammonium formate mixtures as media containing an ionic liquid. A mounting trend with the mole fraction of water in aqueous solution of alcohols up to a maximum at a mole fraction of 0.9 with respect to water was found, but a mild decrease with the mole fraction of ethyl acetate in methanol-ethyl acetate mixtures. A similar increasing trend was observed with increasing methanol, ethanol, 2-propanol and dimethylsulfoxide content in the mixtures containing the ionic liquid. Solvent effect investigations based on linear free energy relationship confirm that polarity has a major effect in molecular-molecular solvent mixtures, whereas polarity and hydrogen-bond acceptor ability were the dominant factors on reaction rate in molecular-ionic solvent mixtures. A nonlinear free energy relationship based on the preferential solvation hypothesis showed differences between the microsphere solvation of the solute and the bulk composition of the solvents. In these mixtures, the intermediate of the reaction was preferentially solvated by the ionic liquid.