AMINOLYSIS OF 4-NITROPHENYL ESTERS OF PHOSPHORUS-ACIDS IN REVERSED MICELLES OF 2-HYDROXYETHYLDIMETHYLPENTADECYLAMMONIUM BROMIDE

The reactions of n-cetyl- and n-hexylamines with 4-nitrophenyl esters of tetracoordinated phosphorus acids in chloroform in the presence of 2-hydroxyethyldimethylpentadecylammonium bromide and the influence of the latter on the acid-base equilibrium of the bromphenol blue dye (BP B) were studied by the spectrophotometric method. In the presence of r eversed micelles of the cationic surfactant, the observed rate constan t of aminolysis increases by more than two orders of magnitude. The ca talytic efficiency of the micelles increases as the concentration of t he long-chain amine decreases and on going from the latter to a short- chain amine. The acid-base equilibrium of BPB in micellar solutions is shifted due to the formation of a complex between the surfactant and the BPB dianion.