Physical and kinetic studies on cetyltrimethylammonium bromide-phenyl acetate systems.

Abstract

The introduction is in three sections, the first of these dealing with the mechanisms and factors affecting the rate of ester hydrolysis. The second part deals with the classification and general characteristics of surface active agents such as micellization and solubilization. The final part discusses micellar catalysis with special emphasis on reactions involving cationic surfactants, particularly cetyltrimethylammonium bromide (CTAB). The experimental section describes the kinetic investigations of the effect of CTAB on the base catalysed hydrolysis of phenylacetate under standard conditions at various pHs. It was found that the surfactant, above its critical micelle concentration (CMC) decreased the rate of hydrolysis. This action was tentatively attributed to the difference in the partition of the ester between the micellar phase and the bulk aqueous phase. Comparison of the partition coefficients determined from the kinetic data with those obtained from solubility and gel filtration techniques support this hypothesis and suggest a change in the physical characteristics of the micelle at a concentration in the region of 1 x 10-2M. Further evidence for such a change was obtained by viscometry and light scattering studies. In the final section the results of these studies are discussed and the importance of pH in micellar catalysis and partitioning behaviour is established.

Date of Award	1975
Original language	English
Awarding Institution	University of Bath