The product of the benzoyl peroxide sensitized oxidation of tetralin is the hydroperoxide as it is in the thermal and heavy metal catalysed oxidations. There is clear evidence that the reaction has a chain mechanism. As the concentration of benzoyl peroxide is increased the oxidation rate rises to a constant value which shows that the peroxide both initiates and terminates the reaction chains. The oxidation rate is proportional to the first power of the tetralin concentration and is characterized by a complex less than first order variation with the oxygen pressure over the entire range of peroxide concentrations. This arises from a chain termination reaction with oxygen, a new feature in liquid-phase oxidations and one which is not present in the therm al oxidation. In view of the accepted free radical character of the benzoyl peroxide decomposition this oxygen termination reaction is thought to be characteristic of a free radical chain oxidation. A suggested mechanism gives an expression for the rate identical with that obtained from the kinetic investigation. By using low peroxide concentrations it has been found that the thermal energy chains and the induced free radical chains proceed simultaneously. Decomposition experiments have shown that in oxidizing systems benzoyl peroxide decomposes faster than in solvents in the absence of oxygen. Using this and other kinetic data the oxidation chain length has been found to be approximately 230.
The oxidation of liquid hydrocarbons III. The oxidation of tetralin in the presence of benzoyl peroxide as a free radical chain reaction
