Alkanes tert-butyl hydroperoxide

The calcined iron-grafted materials exhibit high selectivity as catalysts for oxidations of alkanes, alkenes and arenes with H2O2 as the oxidants [13a]. A similar method has been used by Tilley et al. to prepare a pseudotetrahedral (Co(II) [Co(4,4 -di Bu-bipy) OSi(0 Bu)3 2]) complex grafted onto the SBA-15 surface and subsequently use it in catalytic oxidation of alkylaromatic substrates with tert-butyl hydroperoxide [14]. Unfortunately, neither iron nor cobalt surface organometaUic compounds have been tested in the recycled catalytic system. 

Inserting oxygen into the C-H bond of an alkane initially leads to hydroperoxides. When this reaction is performed with atmospheric oxygen it is also called autooxidation. It usually leads to a multitude of products, because of further spontaneous reactions, so this reaction is of limited synthetic use. An exception is oxidation of isobutane with oxygen, which leads to 70 % yield of tert-butyl hydroperoxide at a conversion of 80% (Table 1, entry 7). Hydrogen bromide is used, among other compounds, as an initiator [15]. tert-Butyl hydroperoxide is used as an oxidant in propylene oxide production by the Halcon process. In the formation of phenol by the cumene process cumene is oxidized into the corresponding hydroperoxide in a similar way. 

Hiatt et a/.34a-d studied the decomposition of solutions of tert-butyl hydroperoxide in chlorobenzene at 25°C in the presence of catalytic amounts of cobalt, iron, cerium, vanadium, and lead complexes. The time required for complete decomposition of the hydroperoxide varied from a few minutes for cobalt carboxylates to several days for lead naphthenate. The products consisted of approximately 86% tert-butyl alcohol, 12% di-fe/T-butyl peroxide, and 93% oxygen, and were independent of the catalysts. A radical-induced chain decomposition of the usual type,135 initiated by a redox decomposition of the hydroperoxide, was postulated to explain these results. When reactions were carried out in alkane solvents (RH), shorter kinetic chain lengths and lower yields of oxygen and di-te/T-butyl peroxide were observed due to competing hydrogen transfer of rm-butoxy radicals with the solvent. 

Tateiwa, J. I., H. Horiuchi, and S. Vemura. 1994c. Mn2+-exchanged clay-catalysed oxidation of alkanes with tert-butyl hydroperoxide. Chem. Commun. 2567-2568. 

The complex [Fe PMA)] also efficiently catalyzes the oxidation of alkanes with tert-butyl hydroperoxide in acetonitrile at room temperature [55], The mechanism proposed by the authors for this reaction involves the formation of free alkyl radicals and their subsequent reaction with O2 (Scheme X.9). The... 

Recently, we have discovered [8], for the first time, that ferrocene (catalyst 1.1) is an efficient (pre)catalyst for several types of oxidative transformations, namely, the oxidation of alkanes and benzene by H2O2 or tert-butyl hydroperoxide. The oxidation of gaseous and liquid alkanes to alkyl hydroperoxides by H2O2 proceeds in MeCN at 50 °C. An obligatory cocatalyst is pyrazine-2-carboxylic acid (PCA, or Hpca, where H is a proton and pea is the anion of PCA). In the cyclohexane oxidation, the yield and TON after 1.5 h attained 32% and 1200, respectively. In the ethane oxidation, TON reached 970. Maximum yield (58% based on the alkane) was obtained for the n-butane oxidation after 4 h. 

Indirect oxidation of propylene is an important route for propylene oxide production that proceeds in two reaction steps. The first step is the formation of a peroxide from alkanes, aldehydes, or adds by oxidation with air or oxygen. The second reaction step is the epoxidation of propylene to PO by oxygen transfer from the peroxide with formation of water, alcohol, or acid. The catalytic oxidation of propylene with organic hydroperoxides is nowadays a successful commercial production route (51% of world capacity). Two organic hydroperoxides dominate the processes (i) a process using isobutane (peroxide tert-butyl hydroperoxide, co-product tert-butyl alcohol), which accounts for 15% of the world capacity and (ii) a process using ethylbenzene (peroxide ethylbenzene hydroperoxide, co-product styrene) that accounts for 33% of the world capacity. The process via isobutane is presented by ... 

Hiatt, Irwin and Gould [328] studied the decomposition of terU mXyX hydroperoxide in the presence of cobaltous and cobaltic stearates (St), octanoates (Oct) and acetylacetonates as well as iron phthalocyanine. They found that the acetylacetonates of Ni(II), Co(III) and Fe(III) were inert toward terUh xiyX hydroperoxide at room temperature. In chlorobenzene or alkanes at 25-45 °C, half lives for decomposition of O.IM ferf-butyl hydroperoxide by 10 M catalyst ranged from 1-10 min with the active catalysts. Products included approximately 88% tert-huXyX alcohol, 11% di-rer -butyl peroxide, 1% acetone and 93% O2. These authors reported that in general, the choice of metal ion, as long as it can undergo a facile one-electron redox reaction, had little effect on products or reaction rates [328]. 

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