Study of Cationic and Nonionic Mixed Micelles with NaBr and 3,5-Cl2C6H3CO2Na by Use of Probe Nucleophilic Reaction of Piperidine with Ionized Phenyl Salicylate

Abstract

Behaviors of cationic and nonionic mixed micelles in the form of hexadecyltrimethylammonium bromide (HDABr) and hexadecyltrimethylammonium bromide-Polyethylene glycol hexadecyl ether (C₁₆E₂₀), in the presence of inert salts (NaBr and 3,5-dichlorosodium benzoate), by the use of reaction probe between Pp and ionized PhSH (Pp = piperidine and PhSH = phenyl salicylate), has been reported in this work. The values of R_X^Br (R_X^Br denotes ion exchange constants obtained in the presence of micelles of different structural features) or K_X^Br (K_X^Br denotes ion exchange constants obtained in the presence of micelles of the same structural features) for 3,5-Cl₂C₆H₃CO₂^- were almost the same at three different [HDABr]_T (0.006, 0.010 and 0.015 M). The average value of R_X^Br or K_X^Br determined, in the presence of pure HDABr micelles, using semi empirical kinetic (SEK) method appeared to be almost 2½-fold larger (R_X^Br or K_X^Br = 198) than that in the presence of mixed HDABr-C₁₆E₂₀ micelles (R_X^Br or K_X^Br = 78). Rheological measurements indicated the existence of wormlike/twisted micelles and vesicle at 0.015 M pure HDABr, various [3,5-Cl₂C₆H₃CO₂Na], and 25 and 35℃ whereas there were evidence of only spherical micelles in the presence of mixed HDABr-C₁₆E₂₀ ([HDABr]_T = 0.015 M and [C₁₆E₂₀]_T = 0.006 M) at both temperatures.

Keywords: hexadecyltrimethylammonium bromide; phenyl salicylate; piperidine; polyethylene glycol hexadecyl ether; vesicle; wormlike micelles.