It has been established that cationic SAS cetyltrimethylammonium bromide catalyses the oxidation of ethylbenzene. The mechanism of catalysis is based on acceleration of the decomposition of alpha-phenylethyl hydroperoxide in combined ROOH-cetyltrimethylammonium bromide aggregates into free radicals with a yield e = 0.2. The effective activation energy of ROOH decomposition E-eff amounts to similar to 50.2 kJ/mole. The possible mechanism of catalysis is discussed.