Kinetics of the reactions of 2,4,6‐tri‐t‐butylphenoxyl with cumene hydroperoxide, cumylperoxyl radicals, and molecular oxygen

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Abstract
Reactions of 2,4,6‐tri‐t‐butylphenoxyl (TBP) with cumene hydroperoxide (ROOH), cumylperoxyl radicals (RO2), and molecular oxygen in benzene solution have been investigated kinetically by the ESR method. The rate constant of the reaction TBP + ROOH magnified image has been estimated in the temperature range 27°‐75°C: log10(k−7/M−1sec−1) = (7.1 ± 0.4) ‐ (10.9 ± 0.6 kcal mole−1)/θThe ratio of the rate constants of reactions TBPH + RO2 magnified image products has been determined from the experimental dependence of the rate constant of reaction TBP with ROOH on [TBPH]0/[TBP]0. Putting k7 = 4.0 × 103M−1sec−1, we obtain k8 = (2.0 ± 0.2) × 108M−1sec−1 at 30°C. The reaction of TBP with O2 obeys the kinetic law −d[TBP]/dt = k′[O2][TBP]2. This is in accordance with scheme TBP + O2 ← TBP ⃛O2 [I]; TBP ⃛O2 + TBP · products, log10 (k′/M−2sec−1) = (−14.5 ± 0.9) + (27.2 ± 1.4)/θ at 66°−78°C, where ° = 2.303RT.