Di-terf-butyl peroxide

Initiators that have been used for these free radical reactions are di-terf-butyl peroxide and 2,2-bis-ferr-butylperoxybutane [166-168]. 

Dimethylhexane-2,5-di-terf.-butyl peroxide, organic peroxide. 

Table I gives the recently measured heats of formation of dimethyl, diethyl, and di-terf-butyl peroxides. Dimethyl peroxide had not previously been burned, but the values for diethyl and di-terf-butyl agreed well with previous work, and the small differences from them were in the expected direction (the heats of formation of unstable compounds, such as peroxides, tend to become more negative with successive measurement). The experimental values were used as standards for the calculation (8) of the group value O—0,C and Table I shows that group additivity is obeyed within the precision of the data.

Hoare and Wellington (22) produced CH3O radicals from the photochemical (50° and 100°C.) and thermal (135°C.) decompositions of di-terf-butyl peroxide in the presence of 02. The initially formed tert-butoxy radicals decomposed to acetone plus methyl radicals, and the methyl radicals oxidized to methoxy radicals. Formaldehyde and CH3OH were products of the reaction the formation of the former was inhibited, and the latter was enhanced as the reaction proceeded. If the sole fate of CH3O were either... 

Gas-phase experiments at 155 °C. were carried out in a 250-ml. cylindrical Vycor reactor in a hot-air furnace. Later experiments were done in a 500-ml. borosilicate glass flask heated in an oil bath. With either system, di-terf-butyl peroxide, oxygen, and isobutane were metered into the reaction vessel in that order by expansion from the vacuum line the pressure of each component was measured using a mercury or oil manometer. Mercury vapor was excluded from the reaction vessel. 

Experiments without Solvents. At our rates of initiation, yields of hydroperoxide, tert-B iO>R/ (A02), in liquid-phase runs were about 75% at 50°, 90 to 93% at 100°C. tert-Butyl alcohol was a major product only at 50°C. with a high rate of initiation (Run 91) acetone was a minor product under all conditions. The termination product, 39% of the expected di-terf-butyl peroxide, was detected in Run 91 where ABN was used as the initiator. 

Dibutyl mercury Di-terf-butyl peroxide Dibutyl o-phthalate Dibutyl sulfate Dibutyl sulfite Dibutyl sulfone Dichloroacetyl chloride 1,2-Dichlorobenzene 3.19 9.7... 

Dibenzoylnaphthalene, 3839 Diborane(6), 0166 Dibromogermane, 0266 Di-terf-butyl peroxide, 3069... 

The efficient reductions observed for various organic halides when treated with Et3SiHin two-fold excess in the presence of catalytic amounts of a thiol and di-tert-butyl hyponitrite as initiator confirmed the validity of this approach. Silane-thiol couples were also used, in boiling octane with di-terf-butyl peroxide as initiator, for the reduction of the methylxanthate of 1,2 5,6-di- O -isopropylidene-a-D-glucofuranose, to yield the corresponding deoxy sugar in 60%173 and 70%174... 

Since 19951, to the best of our knowledge, there have appeared few papers detailing structural investigations of silyl radicals. Of those few, Matsumoto and coworkers investigated the isomerization of silyl radicals derived from 9,10-di-terf-butyl-9,10-dihydro-9, 10-disilaanthracenes (2)6. Irradiation of a di-terf-butyl peroxide (DTBP)/pentane solution of either cis-2 or trans-2 affords the same 81% cist 19% trans mixture of 2. In the absence of DTBP and irradiation, solution NMR studies indicate that each isomer of 2 is unchanged in the —85 to 20 °C temperature range. The authors propose that the radicals 3 derived from 2 isomerize to each other via inversion of the radical centre (equation 1) followed by hydrogen abstraction from the parent compound 2 (an identity reaction). 

Alkyl radicals can be obtained by abstraction of a hydrogen atom from an alkyl group by another radical. This method was utilized for the generation of benzyl radicals from toluene with tert-butoxy radical obtained on heating di-terf-butyl peroxide.38 Benzoyl92 and carboxymethyl88 radicals have also been obtained by this method. The reaction gives rise to a complex mixture of products and therefore is of rather limited use. 

Organic peroxides such as di-terf-butyl peroxide are effective for radical coupling of phenols. 3,5-Dimethylphenol (557) having free ortho- and para-positions was oxidized by heating with di-ferf-butyl peroxide at 140 °C to afford mainly an ortho-ortho coupled product 558 (77%) together with an ortho-para coupled product 559 (16%). In contrast, on oxidation of 557 by di-ferf-butyl peroxyoxalate at 25 °C, the yield (40%) of the ortho-para coupled product 559 increased, while the yield (17%) of 558 decreased. In addition, the para-para coupled product 560 was produced, although the yield (8%) was low (Scheme 103). In the case of phenol, a similar result was also obtained. These results and MINDO-3 calculations with standard parametrization show that stereoelec-tronic factors can explain the preferred formation of the ortho-ortho or ortho-para coupled products. ... 

Di-terf-butyl peroxide is charged into an isothermal, constant-volume batch reactor operated at 480°C. Based on the data below, determine ... 

The y-lactones described below can be prepared in good yield in a one-step process by radical addition of primary fatty alcohols to acrylic acid, using di-terf-butyl peroxide as a catalyst. A patent claims a high yield when the reaction is carried out in the presence of alkali phosphates or alkali sulfates [196]. 

Materials. The polypropylene (PP) used was a low molecular weight crystalline material which has been described previously (8). The polymer was extracted with hexane and acetone before use and dried at 0.1 torr on a steam bath. The extracted pellets had a number average molecular weight (M ) of ca. 29,000 and were completely soluble in benzene at the 120°C reaction temperature. The 9,10-dihydroanthra-cene (DHA) from Aldrich Chemical Company was recrystallized from ethanol before use mp 106°-107°C. Benzene, used directly, was MCB Chromatoquality di-terf-butyl peroxide (terf-Bu2()2) 99% from Lucidol, also was used directly. Azobis(2-methylpropionitrile) (ABN) was Eastman white label grade which was recrystallized from acetone-methanol. 

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