Effects of nonionic micelles on the rate of alkaline hydrolysis of N-(2′-methoxyphenyl)phthalimide (1): Kinetic and rheometric evidence for a transition from spherical to rodlike micelles under the typical reaction conditions

Kinetic Evidence for Near Irreversible Nonionic Micellar Entrapment ofN-(2′-Methoxyphenyl)phthalimide (1) under the Typical Alkaline Reaction Conditions

“…Similarly, the value of R t , at which F IT1 = 0.17, is 12.0 for C 18 E 20 . The values of F IT1 and F IT3 are ~0 [13] and 0.60 [11], respectively, at R = 170 for C 16 E 20 micelles which reveal that the structural features of imide substrates ( 1 and 3 ) (Figure 1) affect the values of F IT1 at a fixed value of R . It is interesting and amazing to note that the difference of only 2 methylene (CH 2 ) groups between C 18 E 20 and C 16 E 20 has so much different effects on F IT1 .…”

“…The values of δ 1 and δ 2 , at 290 nm, are 2480 and 5570 M −1  cm −1 [15], respectively, in aqueous alkaline solvent containing 2% v/v CH 3 CN. The values of δ 1 are independent of [C m E n ] T [13]. The values of δ ap [13] reveal that the values of δ 2 are also independent of [C m E n ] T within its range of 0.0–3.0 mM for C 16 E 20 and C 12 E 23 as well as 0.0–5.0 mM for C 18 E 20 .…”

“…The values of δ 1 are independent of [C m E n ] T [13]. The values of δ ap [13] reveal that the values of δ 2 are also independent of [C m E n ] T within its range of 0.0–3.0 mM for C 16 E 20 and C 12 E 23 as well as 0.0–5.0 mM for C 18 E 20 . However, the values of δ 2 show a nonlinear increase from 5570 to 8450 M −1  cm −1 at 290 nm with the increase in the content of CH 3 CN from 2 to 80% v/v in mixed H 2 O-CH 3 CN solvent [15].…”

“…The values of F IT1 were calculated from (2) at different [C m E n ] T and these values are summarized in Table 1 for C 12 E 23 and Table 2 for C 18 E 20 . It is evident from the calculated values of F IT1 that the value of [C m E n ] T /[NaOH] ( = R ) is nearly 3.6-fold larger for C 18 E 20 than that for C 12 E 23 to result in nearly same value of F IT1 , while the value of F IT1 remains zero even at R = 170 for C 16 E 20 [13]. The typical value of R ( = R t ), at which F IT1 = 0.13, is 3.4 for C 12 E 23 .…”

“…The observed data, absorbance ( A obs ) versus t , obeyed $\begin{array}{c}{A}_{\text{obs}}={\delta }_{\text{ap}}\left[{\mathbf{1}}_{\mathrm{0}}\right]\left[\mathrm{1}-\exp \left(-k_{\text{obs}}t\right)\right]+A_{\mathrm{0}},\end{array}$ where k obs and δ ap represent pseudo-first-order rate constants for alkaline hydrolysis of 1 and molar absorptivity of reaction mixture, respectively, and [ 1 0 ] is the initial concentration of 1 and A 0 = A obs at t = 0. The details of the product characterization are described elsewhere [13]. …”