Initiation in hydrocarbon autoxidation at elevated temperatures

Kinetic and mechanistic investigations of liquid phase autoxidation of hexadecane at 120 to 190°C have shown that, in the early stages of oxidation, the initiation process involves homolytic decomposition of hydroperoxides. The values of a composite first order rate constant for this decomposition, 𝓀 1 , have been determined in stirred flow reactor experiments from the rate of formation of termination products and in batch reactor studies using inhibitor methods. Arrhenius parameters derived from these studies (log ( A /s −1 ) = 8.5 and E a = 26 kcal mol −1 ) allow calculation of 𝓀 1 as a function of temperature. This permits determination of the rate of initiation as a function of hydroperoxide concentration and facilitates determination of absolute rate constants for other oxidation reactions occurring in this system.