Dual-parameter correlations on rate of dehydration step of a condensation reaction in aqueous solutions of ethanol, propan-2-ol and 2-methylpropan-2-ol

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.

Linear Solvation Energy Relationship (Lser) in the Allylation of 2-Mercapto-1-Methylimidazole

The affect of 16 different protic and aprotic solvents on the rate of reaction between allyl bromide and 2-mercapto-1-methylimidazole has been studied. Correlation of the rate constants with different solvent parameters indicates that the polarity, polarisability, electrophilicity and hydrogen bond donor ability of the solvent simultaneously influence the rate. from regression analysis, information about the mode of solvation of the reactants and the transition state is obtained.

LSER in the reaction between p-nitrobenzyl bromide and 2-mercaptobenzoxazole

The reaction between p-nitrobenzyl bromide and 2-mercaptobenzoxazole has been studied by following the conductance of the reaction mixture at different time intervals. The reaction is overall second order, being first order with respect to both [nucleophile] and [substrate]. The reaction is studied in 14 different protic and dipolar aprotic solvents and the second order rate constants are determined. Correlation of rate constants with different solvent parameters indicated that electron pair accepting ability of the solvent (E) and hydrogen bond accepting ability (β) of the solvent simultaneously influence the rate of the reaction.