The influence of 1-hexadecanol on the acid-catalysed hydrolysis of sodium dodecyl sulphate

Abstract

The kinetics at 60° of the acid-catalysed hydrolysis of sodium dodecyl sulphate in the presence of 1-hexadecanol above the critical micelle concentration showed the hydrolysis to be first order and the rate to depend on the molar ratio of alcohol to alkyl sulphate. Up to a ratio of 0.75 the rate increases; above this there is a steady decrease. The changes in rate have been correlated with phase changes and explained on the basis of the effect on the charge density on the micelle, and on the dielectric constant of the associated medium, in passing from a mixed spherical micelle to the lamellar structure and then to the expanded lamellar structure prevailing in liquid crystals.