Mechanism of Acid-Catalyzed Decomposition of Dicumyl Peroxide in Dodecane: Intermediacy of Cumene Hydroperoxide

Acid-catalyzed decomposition of dicumyl peroxide in dodecane from 60 to 130 °C produces α-methylstyrene and phenol as the major products. Pseudo-first-order rate constants were determined as a function of the temperature for the reaction of DCP with dodecylbenzenesulfonic acid in dodecane and resulted in an <i>Arrhenius plot exhibiting two distinct kinetic regimes</i> with differing activation energies: 76.9 kJ/mol at low temperatures (measured from 60 to 90 °C) and 8.50 kJ/mol at higher temperatures (measured from 90 to 130 °C). With employment of a combination of kinetics, product analysis, and trapping experiments, evidence is presented to show the intermediacy of <i>cumene hydroperoxidea reactive intermediate absent from previous mechanistic descriptions of this process.</i> The yield of cumene hydroperoxide production is discussed, and the mechanistic pathways for formation of the observed products are presented