Kinetics and mechanism of base-catalysed hydrolysis of phthalimide
The kinetics of base-catalysed hydrolysis of phthalimide were studied at 1.02M ionic strength in alkaline medium. The data were found to be well fitted with a series first–order consecutive reaction mechanism. The sodium hydroxide concentration dependence of the reaction was found in accordance with k1obs=B1+B2[OH–] and k2obs=C1+C2[OH–] where k1obs and k2obs are rate constants corresponding to general reaction scheme A [graphic omitted] B [graphic omitted] X where A, B, and X stand for phthalimide, phthalamic acid, and ammonia, respectively. The hydrolysis was studied in the temperature range of 60–95 °C. The activation parameters corresponding to first and second consecutive steps of the reaction are: ΔHI*= 19.9 ± 0.3 kcal mol–1, ΔSI*=–21.2 ± 0.8 cal K–1 mol–1; EaI= 20.6 ± 0.3 kcal mol–1, In AI= 19.99 ± 0.75 s–1, and ΔHII*= 10.0 ± 0.5 kcal mol–1; ΔSII*=–50.9 ± 1.32 cal K–1 mol–1, EaII= 10.7 ± 0.5 kcal mol–1, In AII= 6.02 ± 1.31 s–1.