Homogeneous decomposition of dialkylperoxides in oxygen

Abstract

The pyrolysis of n-dialkyl peroxides from 150 to 250 °C is a homogeneous reaction controlled by the intial O—O bond fission. When the reaction occurred in an excess of O₂ and with a reactant concentration of 100 ppm the reaction sequence was as follows: RCH₂O₂CH₂→ 2RCH₂O (1), RCH₂O + O₂→ RCHO + HO₂(2), 2HO₂→ H₂O₂+ O₂. (3) The yields of H₂O₂ and trapped HO₂ radicals have been measured. Rate constant values are as follows: (i) for di-n-heptylperoxide log₁₀k₁/s^–1=(15.00 ± 0.82)–(152.6 ± 9.2) kJ mol^–1/2.303 RT for di-n-butyl peroxide log₁₀k₁/s^–1=(16.02 ± 0.49)–(160.2 ± 10.8) kJ mol^–1/2.303 RT. Such values for A and E are in line with those obtained by another method for dimethyl peroxide and di-t-butyl peroxide and are in agreement with empirical correlations. When di-t-butyl peroxide was studied under the same conditions the main radical observed was CH₃O₂; the main peroxides formed were CH₃O₂H and H₂O₂.