Aryl peroxides

Silyl alkyl and silyl aryl peroxides 7 are prepared by reaction of alkyl, aryl or aralkyl hydroperoxides with halosilanes (equation 12). Such reactions are carried out in an inert solvent in the presence of an acid acceptor, such as pyridine, ammonia or a tertiary amine in ether or petroleum ether (Table 3) . ... 

TABLE 3. Silyl alkyl and aryl peroxides R R R Si—OOR 7 obtained according to equation 12... 

Alkyl and aryl peroxides display C—C—O absorption in the 1198-1176 cm-1 region. Acyl and aroyl peroxides display two carbonyl absorption bands in the 1818-1754 cm-1 region. Two bands are observed be-... 

In his last years, Dr. Isbell became convinced of the importance of saccharide peroxides as reaction products, and not merely as intermediates. He pointed to the structural similarity that exists between hydrazines, hydroxylamines, and peroxides and suggested that a missing group, saccharide peroxides, might be prepared by nucleophilic substitution using suitably protected glycosyl halides and aryl peroxides, as shown in the scheme below. 

They are especially important in the process of thermal and photodegradation of polymers. The primary photodissociation of alkyl and aryl peroxides takes place in the first absorption region. The weak RO-OR bond is disrupted ... 

The reaction stoichiometries, product profiles, and apparent second-order rate constants for the combination of perfluoroaromatic molecules (and several hydro and dihydro derivatives) with excess superoxide ion in dimethylformamide are summarized in Table 7-1. The primary product from the combination of C6F6 with 2 equivalents of O2-- is CeEgOO on the basis of the F-NMR spectrum of the product solution and the mass spectrum for the major peak from the capillary GC of the product solution.24 Similar analyses of the product solutions for the other fluoro substrates are consistent with a peroxide product from the displacement of a fluoride ion. A reasonable first step for these oxygenations is nucleophilic addition of O2 - to the polyfluoroaromatic. Subsequent loss of fluoride ion will give an aryl peroxy radical, which will be reduced by a second O2-- to the aryl peroxide product. This reaction sequence (with the initial nucleophilic displacement the rate-determining step) is analogous to that observed for chlorohydrocarbons and polychlorobenzenes (Scheme 7-8). However, the peroxo product of the latter systems is an effective nucleophile that attacks a second substrate molecule (or an adjacent aryl chlorine... 

Chemiluminescence is observed during the reactions of aryl Grignard reagents with oxygen 4650 or with aryl peroxides.4656 Analysis of the luminescence spectrum and e.s.r. data indicates that for the oxygen-induced reaction brominated biphenyls are the emitters, whereas in the peroxide case triphenylmethane is the luminescent species. 

ALKYL F EROXiDE i ARYL peroxide ANHYDpiDE (opens-chain) " (cycMc) ... 

The first relevant study was recorded by Lamb, who thermolyzed p-substituted aryl peroxides 67. Mainly on the basis of a kinetic study in which the aromatic substituent and the solvent were varied, he concluded that the major pathway for the decomposition is homolytic, with neighboring group participation as pictured in Scheme 36. An analogous study, which reached similar conclusions, was described by Koenig and Martin using compounds 68. Unfortunately, products were not reported by Lamb, who assumed the presence... 

Di-tert-alkyl and di-tert-aryl peroxides (e.g., di-tert-butyl peroxide and dicumyl peroxide) find some use in the production of heat-stable vulcanizates of natural rubber. However, the particular significance of these reagents is that their mode of reaction is rather straightforward and it has been possible to establish a direct quantitative relationship between the number of cross-links in a vulcanizate and its elastic modulus. This correlation is important to the theory of rubber-like elasticity. 

Alkyl/aryl peroxides Rj—O—O—R2 R=(R,=R2)=CH3 R = C2H5(R-C(CH3)202C(CH3)2-R) (CH3)3C0-0C(CH3)20-0C(CH3)3 R = CH2-CH2 R = C=C(CH3)3C0-0C(CH3)2-R-C(CH3)2-0- R = C(CH3)2C6H5 [(01 3)3—0—0—C(CH3)2]2C5H4 C6H5C(CH3)2-0-0-C(CH3)3 Di-tert-butylperoxide (DTBP) Di-tert-amylperoxide (DTAP) 2,2-bis(tert-butylperoxy)butane (BU) 2.5- dimethylhexane-2,5-di-ferf-butylperoxide (DHBP) 2.5- dimethyl-3-hexane-2,5-di-tert-butylperoxide (DYBP) Dicumylperoxide (DCUP) Bis-(2-terf-butylperoxyisopropyl)benzene (DIPP) Tert-butylcumylperoxide (BCHP)... 

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