Effects of cationic surfactant cetylpyridine bromide micelle upon the hydrolysis of 2,4-dinitrochlorobenzene

The reaction between hydroxide ion and 2,4-dinitrochlorobenzene in water was catalyzed by cationic micelles of cetylpyridine bromide (CPB). The rate constant first increased sharply, then remained relatively constant as the concentration of CPB increased, The kinetic form can be interpreted quantatively in terms of incorporation of substrate and hydroxide ion into the cationic micelles, Increasing the hydroxide ion concentration decreased the second-order rate constant of the micellar-catalyzed hydrolysis. The rate enhancement is more pronounced in CPB than in cetyltrimethylammonium bromide system, The difference of the effects of the two cationic micelles has also been discussed.