Catalysis and inhibition of the iodide reduction of peracids by surfactants: partitioning of reactants, product and transition state between aqueous and micellar pseudophases

Effects of Nonionic and Mixed Cationic–Nonionic Micelles on the Rate of Alkaline Hydrolysis of 4-Nitrophthalimide

“…It should be noted that the pH-independent rate of hydrolysis of 4-nitrophthalimide is equal to Similar results were obtained in the study on the effect of mixed C 12 E 23 / CTABr micelles on pK a of phenyl salicylate (6). As has been mentioned earlier, k obs could be determined until [C 12 E 23 ] T became 0.07 M at 0.03 M NaOH (Table 1), so a few kinetic runs were carried out within the [C 12 E 23 ] T range 0.0 to 0.07 M at 0.03 M NaOH and 0.006 M CTABr. The observed results are shown in Fig.…”

“…[1]. k obs only 35% decreases due to an increase in [C 12 E 23 ] T from 0.0 to 0.028 M. However, the ratio R = k h W /k obs ( at 0.028 M C 12 E 23 ) (=1.58) at 0.03 M NaOH is similar to R (=1.54) at 0.01 M NaOH ( Table 1). The values of k obs could not be obtained at [C 12 E 23 ] T ≥ 0.03 M at 0.01 M NaOH because the reaction has almost completely ceased under such conditions.…”

“…Note. The values of k obs , obtained within the [C 12 E 23 ] T range 1 × 10 −4 to 0.028 M at 0.01 M NaOH, could not fit to Eq. [1], which may be attributed to insufficient data points for the nonlinear least squares data fit to Eq.…”

“…The rate of hydrolysis of 4-nitrophthalimide at ≥0.01 M NaOH and [C 12 E 23 ] T = 0 follows the kinetic equation…”

“…The effects of mixed cationic/anionic surfactants on the rates of methanolysis of ionized phenyl salicylate (PS − ) and alkaline hydrolysis of phenyl benzoate have revealed that mixed micelles show a cationic nature when X ≤ 0.3 and an anionic nature when X ≥ 4, where X = [SDS] T /[CTABr] T (SDS = sodium dodecyl sulfate and CTABr = cetyltrimethylammonium bromide) (5). The pK a of phenyl salicylate remains unchanged with the change in [CTABr] T /[C 12 E 23 ] T from 0.5 to 1.5 at a constant [C 12 E 23 ] T (= 0.02 M), which seems to be an unexpected result (6). The present study was initiated with the aim of investigating the effects of C 12 E 23 (i.e., Brij 35) and mixed CTABr/C 12 E 23 micelles on the rate of alkaline hydrolysis of 4-nitrophthalimide.…”