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Résumé :
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A selective and mild (55 °C and 50 psig) homogeneous oxidation system has been described to produce hydroperoxides from a narrow cut made from typical gas oil. During this process oil, dissolved in wet acetic acid, is treated with air in the presence of the redox couple Co(III)/Co(II) (partially oxidized catalyst, POC). A straightforward route to POC consists of oxidizing Co(II) in wet acetic acid with calculated aqueous potassium chlorate. Initiation is the manifestation of the potent oxidizing ability of Co(III) toward generating alkyl radicals from hydrocarbons in the oil. Classical propagation then leads to assorted hydroperoxides, simultaneously decomposed by POC. Kinetics of the simultaneous formation and decomposition of hydroperoxides, under varying sets of process and composition variables, was studied in an isothermal, mechanically agitated, semibatch reactor, operating in the pure kinetic regime. A unique kinetic model, based on a rare irreversible consecutive reaction network (pseudo-first-order formation of hydroperoxides followed by their second-order decomposition), has been found to reasonably describe the kinetic data (R2 = 0.9214). This kinetic model allowed the evaluation of the formation and decomposition rate constants that permitted the estimation of conversion of oil and selectivity to hydroperoxides. On average 15.12 ± 3.23% conversion was achieved in 9.3 ± 4.0 min with 99.86 ± 0.23, 92.88 ± 7.95, and 28.77 ± 11.67% selectivities for 0.10, 1.00, and 10.0% conversions, respectively.
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