Summary o 1. Solutions of anthracene and cyclohexene in 93% sulphuric acid are sources of fairly stable species, which oxidize tertiary and secondary C−H bonds of saturated hydrocarbons at 90°C. A study was made of kinetics and selectivity of the first stage of oxidation of paraffins in these systems. 2. The selectivity, isotope effect and kinetics of oxidation of the anthracene-H 2SO 4 system and oligomers of cyclohexene-H 2SO 4 are similar and approximate to the oxidizing agent-sulphuric acid systems, previously examined. 3. Based on this analogy a mechanism was proposed for the oxidative homolysis of C-H bonds for the first stage of oxidation of saturated hydrocarbons in anthracene-sulphuric acid and cyclohexene-sulphuric acid systems.