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

✍ Scribed by A. P. Griva; E. T. Denisov

• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: English
• Weight: 318 KB
• Volume: 5
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550050513

✦ Synopsis

Reactions of 2,4,6-tri-t-butylphenoxyl (TBP) with cumene hydroperoxide (ROOH), cumylperoxyl radicals (RO,), and molecular oxygen in benzene solution have been investigated kinetically by the ESR method. The rate constant of the reaction TBP + ROOH -% TBPH + RO2 has been estimated in the temperature range 27"-75"C: Iog,~(k-~/M-'sec-') = (7.1 0.4) -(10.9 + 0.6 kcal mole-l)/O The ratio of the rate constants of reactions TBPH + ROt % TBP + ROzH and TBP -+ R o t + products has been determined from the experimental dependence of the rate constant of reaction TBP with ROOH on [TBPHJo/[TBP]o. Putting k , = 4.0 X 103M-'sec-', we obtain kg = (2.0 + 0.2) X 1O8M-'sec-' at 3OoC. The reaction of TBP with Oz obeys the kinetic law -d[TBP]/dt = k'[O2][TBPI2. This is in accordance

with scheme TBP + 0 2 + TBP ... 0 2 [I]; TBP ... 0 2 + TBP --+ products, log,, (k'/M-2sec-1) = (-14.5 f 0.9) + (27.2 + 1.4)/6 at 66"-78"C, where 8 = 2.303RT.