ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 20, Number 3
JKCSEZ 20(3)
June 20, 1976 

The kinetics of hydrolysis of hydrazonyl bromides (p-H, p-CH3, p-OCH3, p-Br, p-Cl & p-NO2) have been investigated by UV spectrometry in 60% dioxane-water at 25℃ and a rate equation which can be applied over wide pH range was obtained. Below pH2, the rate of hydrolysis of a series of hydrazonyl bromide is accelerated by electrondonating group (ρ = -0. 94) whereas at the pH values greater than 4, the ρ-value is 0.54. The rate equation, solvent-, substituent-and bromide ion-effect on the rate of hydrolysis are rationalized in terms of SN1 and SN2 mechanism: below pH 2, the hydrolysis proceed through SN2, however, above pH 4, the hydrolysis is started by the attack of hydroxide ion and in the range pH 2∼4, these two reactions occur competitively.