Kinetics and Mechanism of Alkaline Hydrolysis of N-(o-Aminophenyl)Phthalimide in the Presence and Absence of Cationic Micelles and Sodium Salts of Aliphatic Acids

Pseudo first-order rate constants, k obs, for the alkaline hydrolysis of N-( o-aminophenyl) phthalimide, obtained at constant [CTABr]T (total concentration of cetyltrimethylammonium bromide) and varying concentrations of inert salt MX (MX = sodium formate, sodium acetate, sodium propanoate, sodium butyrate, sodium valerate and sodium hexanoate) follow the relationship: [Formula: see text], where θ and KX/S are empirical constants and S = HO-. The values of KX/S for each aliphatic acid decrease with an increase in [CTABr]T. This relationship gives an empirical constant whose magnitude is the measure of the ability of an ion, X-, to expel another counterion S-, from the cationic micellar surface to the bulk aqueous phase. The values of the empirical constant, KX/S, are used to derive the ion exchange constant, KBrX.

Synthesis of ZnO and ZrO2 Powders by Mechanochemical Processing

The ZnO and ZrO2 powders were prepared by mechanochemical processing and subsequent heat treatment of the starting powder of precursors mixture of ZnCl2 and Ca(OH)2, and ZrOCl2·8H2O and NaOH, respectively. Inert salt matrix, ether CaCl2 or NaCl, which prevents particle agglomeration was formed during mechanochemical solid state reaction. After mechanochemical treatment, samples were calcined at various temperatures. Selective removal of the matrix phase by washing the resulting powder with appropriate solvent yields almost pure ZnO and ZrO2 powders. Characterization of the powders was performed by X-ray diffraction (XRD), differential thermal and thermo gravimetric analysis (DTA−TG) and scanning electron microscopy (SEM).

Spectrophotometric determination of Cationic Micellar Binding Constant of Ionised Phenyl Salicylate in the presence of Inert Salts

A spectrophotometric technique has been used to determine the cetyltrimethylammonium bromide (CTABr) micellar binding constant ( KS) of ionised phenyl salicylate (PS-) in the presence of a constant amount of inert salt (MX = NaBr or C6H5COONa). The values of KS at different [MX] follow an empirical relationship: KS = KS0/(1 + KX/S[MX]) where the magnitude of the empirical parameter KX/S is the measure of the ability of X- to expel S- (= PS-) from the CTABr micellar pseudophase to the aqueous pseudophase. The value of KX/S is nearly 13-fold larger for C6H5COO-than for Br-.

Solvent effects on nucleophilic substitution reactions. III. The effect of adding an inert salt on the structure of the SN2 transition state

The nitrogen and secondary α-hydrogen–deuterium kinetic isotope effects found for the SN2 reaction between thiophenoxide ion and benzyldimethylphenylammonium ion at different ionic strengths in DMF at 0 °C indicate that the structure of the transition state changes markedly with the ionic strength of the reaction mixture. In fact, a more reactant-like, more ionic, transition state is found at the higher ionic strength. This presumably occurs because a more ionic transition state is more stable in the more ionic solvent. Key words: transition state, ionic strength, secondary α deuterium kinetic isotope effects, nitrogen isotope effects, SN2.

On the origin of base concentration effect on stereo- and regioselectivity in alkoxide-promoted E2 reactions: A consequence of substrate solvation by metal ions

The title problem has been investigated in the reaction of 2-decyl bromide with t-C4H9OK/t-C4H9OH system employing 18-crown-6 ether and an "inert" salt (t-C4H9OLi) as mechanistic probes. From olefin-distribution data and a subsidiary kinetic evidence it has been inferred that the investigated effect originates from a concentration-dependent substrate solvation by metal ions in the transition state.