Abstract
The kinetics of base-catalysed hydrolysis of phthalimide were studied at 1.02
M
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
k
1obs
=
B
1
+
B
2
[OH
-
] and
k
2obs
=
C
1
+
C
2
[OH
-
] where
k
1obs
and
k
2obs
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: Δ
H
I
*= 19.9 ± 0.3 kcal mol
-1
, Δ
S
I
*=-21.2 ± 0.8 cal K
-1
mol
-1
;
E
aI
= 20.6 ± 0.3 kcal mol
-1
, In
A
I
= 19.99 ± 0.75 s
-1
, and Δ
H
II
*= 10.0 ± 0.5 kcal mol
-1
; Δ
S
II
*=-50.9 ± 1.32 cal K
-1
mol
-1
,
E
aII
= 10.7 ± 0.5 kcal mol
-1
, In
A
II
= 6.02 ± 1.31 s
-1
.