Di-r-butyl peroxide

Olefins obtained from petroleum cracking gave mixed dipropylalkylphos-phonates when heated in a similar manner with dipropyl phosphite in the presence of di-r-butyl peroxide for 16 h at 130°C. 

Methylation is taken as illustrative of alkylation for comparative purposes in Table 25 however, a wide range of other alkylations have been studied (76MI20503). Photolysis of di-r-butyl peroxide in a mixture of cyclohexane and pyridine gives cyclohexylation (equation 170) (7lCR(C)(272)854>. The relative rates for homolytic substitution of pyridines by cyclic alkyl radicals have been obtained (74JCS(P2)1699). A striking contrast can be seen (Table 26)... 

Hydroperoxides and peroxides oxidize primary and secondary aliphatic amines to imines. Thus f-butyl hydroperoxide oxidizes 4-methyl-2-pentyl-amine to 2-(4-methylpentylidene)-4-methyl-2-pentylamine in 66% yield [29]. Di-r-butyl peroxide reacts in a similar manner [29]. However, this reaction is... 

The HPLC method with CLD described in Section V.B.2.C for determination of hydroperoxides using luminol (124) with hemin (75a) catalysis is ineffective with dialkyl peroxides, such as di-r-butyl peroxide, cumyl propyl peroxide and cumyl 3-phenylpropyl peroxide. However, for a certain set of experimental conditions, cumyl allyl peroxide can be determined, but the sensitivity is much lower than for hydroperoxides164. 

The compounds 43, 45, 48b and 48c gave the corresponding disiloxanes in quantitative yields, and BTSP is converted into hexamethyldisiloxane, 44, formed from difluorote-tramethyldisiloxane. The reaction of 44 with BTSP was not inhibited by 2,4,6-tri(/-butyl)phenol. Compound 48a did not react with di-r-butyl peroxide, which is the carbon analog of BSTP, suggesting an important role of vacant d-orbitals of the silicon atom. The Si—Si oxidation of compound 49 with BSTP proceeds quantitatively and in a stereospecific fashion (equation 72)63. 

Di-/-butyl-4-methylpyridine, 160 Di-/-butyl nitroxide, 160-161 Di-r-butyl peroxide, 131... 

Deoxygenation of ROH. Acetates, primary, secondary, or tertiary, are deox-> genated when heated with 1 in the presence of a radical initiator, di-r-butyl peroxide (DTBP). Yields using (C6H5)3SiH in place of 1 are definitely lower. The presence of a double bond in the substrate can lower yields owing possibly to hydrosilylation. 

Many organic peroxides and hydroperoxides are known.30 Peroxo carboxylic acids (e.g., peroxoacetic acid, CH3CO OOH) can be obtained by the action of H202 on acid anhydrides. Peroxoacetic acid is made as 10 to 55% aqueous solutions containing some acetic acid by interaction of 50% H202 and acetic acid, with H2S04 as catalyst at 45 to 60°C the dilute acid is distilled under reduced pressure. It is also made by air oxidation of acetaldehyde. The peroxo acids are useful oxidants and sources of free radicals [e.g., by treatment with Fe2+(aq)]. Dibenzoyl peroxide, di-r-butyl peroxide, and cumyl hydroperoxide are moderately stable and widely used as polymerization initiators and for other purposes where free-radical initiation is required. 

Chlorohydroxylotion of alkenes. Anhydrous -butyl hydroperoxide or di-r-butyl peroxide (1, 211-212) in the presence of TiCh effects chlorohydroxylation of alkenes. 

Reduction of aryl and alkyl halides.5 This reaction can be conducted in generally good yield with LiAlH4 by a free-radical process initiated by irradiation of di-r-butyl peroxide. The order of reactivity of aryl halides is Arl > ArBr > ArCl > ArF. Alkyl and cycloalkyl halides are reduced efficiently, but vinyl bromides are reduced in only modest yield. 

Under similar conditions chromium(VI) oxide and PCC woe found to be less effective. Other cooxidants were also examined hydrogen peroxide gives unacceptable amounts of overoxidation of aldehydes, whilst t-butyl hydroperoxide, di-r-butyl peroxide and benzoyl peroxide all failed as cooxidants. 

The thermal decomposition, of di- r -butyl peroxide has been fairly extensively studied in order to obtain the dissociation energy of the peroxide link, which is expected to be the weakest in the molecule. Milas and Surgenor347 found that the only products of decomposition in the gas phase at 250G were ethane and acetone, which suggests a simple bond splitting mechanism, followed by very straightforward radical reactions,... 

The pyrolysis of di-/ r/-butyl peroxide has been studied by several workers (Section 4.2). The value of 37 kcal for Z)(0-0) is probably correct 24, The error found in Tossing and Tickner s activation energies is probably not present at the temperature used... 

The substitution of aluminum by oxygen can be effected by various peroxide derivatives, such as di-r-butyl peroxide, benzoyl peroxide and r-butyl perbenzoate. The main reaction is accompanied by telltale free-radical side reactions, such as the formation of RR from R3AI, which become major pathways with aryl and vinyl compounds. Oxidation of alkenyl derivative (56) with r-butyl perbenzoate yields 45% of a mixture of cis and trans ethers (57 equation 44). As of yet there is no generally applicable, highly efficient method for oxidizing vinylaluminum compounds. 

Single fluorine atoms in aromatic fluoro compounds such as p-fluorotoluene and p-fluoroanisole are replaced by hydrogen using lithium aluminum hydride in the presence of di-r-butyl peroxide under irradiation (equation 37). ... 

Examples of hydrogenolysis of aryl chlorides by lithium aluminum hydride are rare. Chlorobenzene is reduced to benzene only in a low yield, but chloronaphthalene gives a good yield of naphthalene with lithium aluminum hydride in the presence of either di-r-butyl peroxide or titanium tetrachloride (equation 51 ). ... 

Reduction of aryl bromides with lithium aluminum hydride takes place in tetrahydrofuran solutions at room temperature. It has also been performed with bener results in the presence of di-r-butyl peroxide under UV irradiation or in the presence of titanium tetrachloride (equations 56 and 57). Reduction of bromobenzene with sodium bis(methoxyethoxy)aluminum hydride (Red-Al, Vitride) at 100-115 C gives benzene in 53% yield (Table 4). ... 

The decomposition of acetaldehyde, sensitized by biacetyl, was studied at 499 °C by Rice and Walters , and between 410 and 490 °C by Boyer et al. They found the initial rate to be proportional to the square root of the biacetyl concentration and to the first power of the aldehyde concentration. The chains are initiated by the radicals originating from the decomposition of the biacetyl molecule. The decomposition of acetaldehyde can be induced also by di-r-butyl peroxide (at 150-210 °C, about 10-50 molecules decompose per peroxide molecule added), as well as by ethylene oxide (around 450 °C each added ethylene oxide molecule brings about the decomposition of up to 300 acetaldehyde molecules). For the influence of added diethylether, vinyl ethyl ether, ethyl bromide, and ethyl iodide etc., see Steacie °. 

The slight effect of solvent upon the rate of decomposition is characteristic of tertiary dialkyl peroxides. For example, the rate of decomposition of di-r-butyl peroxide is altered only slightly by changing from the gas phase through hydrocarbon solvents to tri-n-butyl amine (Table 66). These results indicate that there is little ionic character in the activated complex of the rate-determining step (2). 

Not surprisingly, adenine and guanine have been a major focus of many studies in this field and in alcohol solutions with irradiation at wavelengths >290 nm, 8-hydroxyalkyl derivatives are produced. The yields are improved by use of sensitizers such as acetone and di-r-butyl peroxide (73JOC3420). With substituted purines, attack may also occur at the substituent group as with caffeine which in 2-propanol produced (174). 

Radicals Azobisisobutyronitrile. a,T-Bis(diphenylene)-d-phenylallyL r-Butyl perbenzoate. 7-Butyrolactone. Dibenzoyl peroxide. Di-r-butyl nitroxidc. Di-r-butyl peroxide. Diphenyl-picrylhydrazyl. Galvinoxyl. Hydrogen peroxide-iron salts. Lead dioxide. N-Phenyl-N -benzoyldiimide. Potassium nitrosodisulfonate. Thiolacetic acid. Trichloromethanesulfonyl chloride. 

Polymers containing oxazoline groups are obtained either by grafting the 2-oxazoline onto a suitable existing polymer such as polyethylene or polyphenylene oxide or alternatively by copolymerising a monomer such as styrene or methyl methacrylate with a small quantity (<1%) of a 2-oxazoline. The grafting reaction may be carried out very rapidly (3-5 min) in an extruder at temperatures of about 200°C in the presence of a peroxide such as di-r-butyl peroxide Figure 7.13). 

The reaction of alkylmagnesium reagents with di-r-butyl peroxide leads to alkyl r-butyl ether, t-butyl alcohol, and disproportionation products of the alkyl [96]. Mechanistic studies showed that the initial step is ET. This conclusion was i.a. based on a linear correlation of log rate with the oxidation potentials of the Grignard reagents. Reactions of peroxides are extremely sensitive to metal catalysis, but take place even when high-purity magnesium is used. 

The kinetics of the thermal decomposition of di-r-butyl peroxide in toluene were determined by Tou and Whiting (172). They found the kinetic parameters to be E — 37.8 1.1 kcalmol and log A = 16.15 0.61 sec"1. This compares favorably with E = 37.78 + 0.06 kcalmol and log. 4 = 15.80 0.03 sec 1 determined by Shaw and Pritchard (173) from a least-squares treatment of 177 data points obtained by various workers. The highest selfheat rates that the calorimeter can follow without deviation from the... 

The reactions are further classified into three major categories radical chain reactions, transition metal catalyzed reactions, and base-catalyzed reactions. In the radical chain reactions, dibenzoyl peroxide, di-r-butyl peroxide and a,a azobisisobutyronitrile (AIBN) are used most frequently as an... 

The addition of dialkyl hydrogenphosphonates to tetrafluoroethene occurs in the presence of di- r butyl peroxide to give the series of polyfluoroalkyl phosphonic diesters, H(CF2CF2) P(0)(0R)2 (n = 1-3) the free acids with n = 1-5 and the corresponding phosphonic dichlorides with n = 1-9 have also been recorded ... 

---