A kinetic study of the reaction of acetylsalicylic acid (aspirin) with sodium hydroxide has been studied in the presence of some conventional and novel cationic surfactants. The pseudo-first-order rate constant increases with the surfactant concentration initially and then decreases. In comparison to conventional cationic surfactants, i.e., cetyltrimethylammonium bromide and cetylpyridinium bromide, novel alkyldiethylethanolammonium bromide (R = C 16 ) surfactant accelerated the alkaline hydrolysis significantly. The pseudophase ion-exchange model has been applied to fit the experimental results.
Kinetic measurements were performed for the hydrolysis of p-nitrophenyl acetate as a model compound in micellar media. This reaction was studied both in the presence and absence of various α-effect nucleophiles, and in depth analyses were performed using acetohydroxamic acid (AHA). Rate surfactant profiles were obtained in the absence and presence of the AHA nucleophile for the alkyl triphenylphosphonium bromides (CnPPh3Br) surfactant series. All rate surfactant profiles were analyzed using the pseudophase model and modified pseudophase model (In the presence of nucleophile) in order to obtain the regression parameters, including binding constants and rate constants in the micellar pseudophase. Studies in the presence of acetohydroxamic acid and the alkyl triphenylphosphonium surfactants were also conducted as a function of pH to obtain the pKa value of the acetohydroxamic acid in the micellar media.
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