Solvent effects on kinetics of the reaction between 2-chloro-3,5-dinitropyridine and aniline in aqueous and alcoholic solutions of [bmim]BF4

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

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.

Systems Designed with an Ionic Liquid and Molecular Solvents to Investigate the Kinetics of an SNAr Reaction

The microscopic features of binary solvent systems formed by molecular solvents (methanol, ethanol, 2-methylpropan-2-ol, water, pyridine, acetonitrile, 1-propanol, 2-propanol, dimethylformamide) and the ionic liquid ([bmim]BF4) as cosolvent were used to select mixed solvents with particular characteristics. Molecular-microscopic solvent parameters corresponding to these binary mixtures were utilised to study the kinetics of the nucleophilic substitution reaction between 2-chloro-3,5-dinitropyridine and aniline to investigate and compare the effects of the solvents on a model chemical reaction. For these mixtures, the solvation behaviour is dominated by both the dipolarity/polarisability and hydrogen bonding interactions of the media. In these solutions, the rate constants of the reaction decrease with the mole fraction of ionic liquid.

Solvent Polarity, Hydrogen-Bonding and Solvophobicity Effects on the Nucleophilic Substitution of Benzenesulfonyl Chloride with Aniline in Aqueous and Non-Aqueous Solutions of Methanol

The reaction between benzensulfonyl chloride and aniline was studied in various compositions of methanol with ethyl acetate, propan-2-ol and water at 25° C. Second-order rate coefficients of this reaction were determined; those in pure solvents were in the order of water > methanol >propan-2-ol> ethyl acetate. Rates decreased sharply with the mole fraction of ethyl acetate in methanol- ethyl acetate mixtures and showed an increasing trend with water content in methanol-water mixtures. Linear free energy relationship regressions showed that the polarity, hydrogen-bond donor ability and hydrophobicity of the media were the main factors affecting the reaction rate coefficient.