Kinetic Studies of Acenaphthene Oxidation Catalyzed by N‐Hydroxyphthalimide

Abstract

The acenaphthene oxidation with molecular oxygen in the presence of Nhydroxyphthalimide (NHPI) has been investigated. It is shown that the main oxidation product is acenaphthene hydroperoxide. The phthalimide-N-oxyl (PINO) radical has been generated in situ from its hydroxyimide parent, NHPI, by oxidation with iodobenzenediacetate. The rate constant of H-abstraction (k H ) from acenaphthene by PINO has been determined spectroscopically in acetonitrile. The kinetic isotope effect and the activation parameters have also been measured. On the basis of the results of our studies and available published literature data, a plausible mechanism for the oxidation process of acenaphthene with dioxygen catalyzed by NHPI was discussed. C 2013 Wiley Periodicals, Inc. Int J Chem Kinet 45: [515][516][517][518][519][520][521][522][523][524] 2013 Polycyclic aromatic hydrocarbons with secondary C-H bonds, for example, acenaphthenes (AcNph) are oxidized by using dioxygen to their corresponding oxygenated derivatives, naphthalic acid and naphthalic anhydride, which are used as intermediates for the synthesis of the important raw materials (such as esters, amides, and imides) for the manufacture of dyes, pharmaceuticals, pesticides, plastics, fibers, curing agents, plasticizers, pigments, fluorescent whiteners, and many other items [9]. Polynuclear hydrocarbons were oxidized during catalysis of NHPI [10], [11], but no literature report has been published on the efficient oxidation of acenaphthene except [10], where authors used the NHPI/anthraquinone system. In this paper, we have reported the kinetic study of the acenaphthene oxidation by molecular oxygen in the presence of NHPI, to better understand the mechanism of the NHPI-catalyzed aerobic oxidation of alkylbenzenes. We have described

Kinetics of oxidation of benzyl alcohols with molecular oxygen catalyzed by N‐hydroxyphthalimide: Role of hydroperoxyl radicals

“…The kinetics of radical‐chain mechanism of NHPI‐catalyzed oxidation of organic substrates (RH) has been widely investigated . NHPI is thought to catalyze oxidation through the generation of the PINO radical.…”

The Oxidative Polymerization of Vinyl Monomers in the Presence of N‐Hydroxyphthalimide

“…Polyperoxides were characterized by IR (for MMA) and 1 H NMR spectra (for MMA, St and α ‐MSt). On the IR spectrum of MMA polyperoxide (PPMMA) the band corresponding to the C=C bond of the monomer MMA at 1650 cm −1 disappears.…”

“…The addition of NHPI to the reaction mixture significantly increase oxidation rates of vinyl monomers initiated by AIBN or BPO, moreover NHPI initiates the oxidative polymerization in the absence of AIBN or BPO. Similar dependencies we observed for MMA . It should be noted that under the conditions of our experiments, in the absence of AIBN, BPO or NHPI oxygen uptake wasn't observed.…”

“…Earlier we found that the oxidative and anaerobic polymerization rates are proportional to the square root of the initiator concentrations (AIBN or BPO) …”

“…NHPI has a dual function in the radical polymerization of methyl methacrylate (MMA): this compound acts as an initiator and provides for stereochemical control of the polymer chain . NHPI can effectively initiate not only homopolymerization, but also oxidative polymerization of MMA and styrene (St) …”