Kinetics of the acidic hydrolysis of fenuron in the aqueous and micellar media

Abstract

The kinetics of the hydrolysis of fenuron by hydrochloric acid in aqueous methanol solution was studied spectrophotometrically. The influence of cationic micelles of cetyltrimethylammonium bromide and anionic micelles of sodium lauryl sulfate on the rate of hydrolysis of fenuron have also been studied. The anionic micelles increased the rate of reaction, while the cationic micelles decreased the rate of hydrolysis. The reaction followed first-order kinetics in [fenuron]. The rate of reaction was increased with increase in [HCl] in lower range, but become constant at higher concentration in aqueous and micellar pseudophases. The reaction starts with the protonation of amino group of fenuron followed by rate-determining attack of water. The results in micellar media are accounted for on the basis of distribution of substrate into micellar and aqueous pseudophases.