Kinetics of the neutral hydrolysis of 4-nitrophenyl chloroacetate was investigated in water and in the presence of 1 mol % of ethanol, propanol, and n-butyl alcohol without sonication and under ultrasound at 25 kHz. Similarly, the kinetics of the acid-catalysed hydrolysis of n-propyl acetate in ethanol–water binary solutions was investigated without sonication and under ultrasound at 22 kHz. The results are discussed together with corresponding data for ethyl and n-butyl acetate from previous works. It was concluded that for ester hydrolyses the solvent effects in an aqueous alcohol binary mixture are limited almost entirely to the hydrophobic ground-state stabilization by the organic co-solvent.
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