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Studies done on the kinetics of the acid-catalyzed hydrolysis of ethyl, propyl, and butyl acetates in aqueous binary mixtures of ethanol and of 1,4-dioxane without sonication and under ultrasound at 22 kHz is presented. Results of the study reveal that sonochemical reaction of esterhydrolysis in ethanol-water and 1,4-dioxane-water mixtures can be interrelated with the destruction of the molecular structure of the binary solvent and essentially with the perturbation of hydrophobic solute-solvent interactions.

The solvation, complexation, disproportionation equilibria, which is important during titration of a Grignard reagent RMgX with an alcohol in the presence of 1,10-phenanthroline (phen) are studied both in the gas phase and solution using density functional theory (DFT) B3LYP/6-31+G* method. The calculations show that the complexation of magnesium halide MgX2 with 1,10-phenanthroline is the reason for the disappearance of the red color of the complex RMgX (phen) near the titration end point.

A study is conducted to determine the kinetics of KCN-catalyzed benzoin condensation of benzaldehyde in water and ethanol-water binary mixtures both under ultrasound at 22 kHz and without sonication. The ultrasound affects hydrophobic interactions with the solvent, whereas the sonication has hindered the reaction when it suppresses the stabilization of the encounter complexes between reagents.

The kinetics of base-catalyzed hydrolyzed of 4-nitrophenyl acetate is analyzed in water and water-ethanol mixtures under ultrasound using a probe equipped with a quartz horn and, by comparison, without sonication. The results have shown that the effect of ultrasound might be related to the perturbation of solute-solvent interactions, which can be applied to both acid-catalyzed and base-catalyzed hydrolysis reactions.

The results of dynamic examination of the Grignard reactions with chlorosilanes in tetrahydrofurane (THF) and THF-hydrocarbon mixtures are examined. An analysis of kinetic data related to data for the Schelenk equilibrium is presented.

Density functional theory (DFT) B3LYP/6-31+G* method is used to study the Schlenk equilibrium involving RMgX, R2Mg, and MgX2 both in the gas phase and in diethyl ether (Et2O) and tetrahydrofuran (THF) solutions. The stabilization due to interaction with solvent molecules decreases in the order MgX2 > RMgX > R2Mg and among the groups (R and X) Ph > Me > Et and Cl > Br.

Using diethyl ether and diethyl ether-toluene mixtures, the kinetics of the reactions of butylmagnesium chloride and phenylmagnesium bromide with teraethoxysilane and methyltrichlorosilane were investigated. It was found that large negative activation entropies are consistent with the formation of cyclic transition states.

The kinetics of KCN-catalyzed benzoin condensation of benzaldehyde in water and ethanol−water binary mixtures was investigated both under ultrasound at 22 kHz and without sonication. Thermodynamic activation parameters were calculated from kinetic data obtained at 35, 50, and 65 °C. Evidence that ultrasound can retard reactions is reported and hence a direct proof that sonochemical processes occur in the bulk solution. Former results and literature data for ester hydrolyses and tert-butyl chloride solvolysis are involved in the discussion. A quantitative relationship between sonication effects and the hydrophobicity of reagents is presented for the first time. Ultrasound affects hydrophobic interactions with the solvent, which are not manifested in conventional kinetics. When it suppresses the stabilization of the encounter complexes between reagents, sonication hinders the reaction but accelerates it when it perturbs the hydrophobic stabilization of the ground state of a reagent. [ABSTRACT FROM AUTHOR]