Di -ferf-butyl peroxide

The determination of A V is illustrated by data for the thermal decomposition of di-ferf-butyl peroxide.10 The rate constants at 120 °C in toluene are as follows ... 

The submitters report that this free radical cyclization was also effected by heating a solution of 5.00 g. (0.026 mole) of ethyl (E)-2-cyano-6-octenoate and 1.25 g. (0.0086 mole) of di-ferf-butyl peroxide [bis(l,l-dimethylethyl)peroxide] in 500 ml. of freshly distilled cyclohexane at 140° in an autoclave for 30 hours. The solution was concentrated and the residue was distilled to yield 3.4 g. (68%) of ethyl l-cyano-2-methylcyclohexanecarboxylate. 

The addition of (TMS)3SiH to a number of monosubstituted acetylenes has also been studied in some detail. These reactions are highly regioselective (anti-Markovnikov) and give terminal (TMSlsSi-substituted alkenes in good yields. High cis or trans stereoselectivity is also observed, depending on the nature of the substituents at the acetylenic moiety. For example, the reaction of the alkynes 23 and 24 with (TMSlsSiH, initiated either by EtsB at room temperature (method or by thermal decomposition of di-ferf-butyl peroxide at 160 °C... 

Though relatively stable,explosions have been caused by distillation to dryness [1], or attempted distillation at ambient pressure [2]. In a comprehensive review of the use of the hydroperoxide as a selective metal-catalysed oxygenator for alkenes and alkynes, attention is drawn to several potential hazards in this application. One specific hazard to be avoided stems from the fact that Lucidol TBHP-70 contains 19% of di-ferf-butyl peroxide which will survive the catalysed reaction and may lead to problems in the work-up and distillation [3], A thorough investigation of the stability and explosive properties of the 70% solution in water has been carried out [4]. The anhydrous peroxide as a solution in toluene may now readily be prepared azeotropically, and the solutions are stable in storage at ambient temperature. This solution is now a preferred method for using the anhydrous hydroperoxide [5],... 

Biesenberg, J. S. etal., J. Polym. Eng. Sci., 1976,16, 101-116 Polymerisation of methyl methacrylate initiated by oxygen or peroxides proceeds with a steady increase in velocity during a variable induction period, at the end of which a violent 90°C exotherm occurs. This was attributed to an increase in chain branching, and not to a decrease in heat transfer arising from the increasing viscosity [ 1 ]. The parameters were determined in a batch reactor for thermal runaway polymerisation of methyl methacrylate, initiated by azoisobutyronitrile, dibenzoyl peroxide or di-ferf-butyl peroxide [2],... 

Photolytic. PCB-1254 in a 90% acetonitrile/water solution containing 0.2-0.3 M sodium boro-hydride and irradiated with UV light (X = 254 nm) reacted to yield dechlorinated biphenyls. After 16 h, no chlorinated biphenyls were detected. Without sodium borohydride, only 25% of PCB-1254 were destroyed after 16 h (Epling et al, 1988). In a similar experiment, PCB-1254 (1,000 mg/L) in an alkaline 2-propanol solution was exposed to UV light (X = 254 nm). After 30 min, all of the PCB-1254 isomers were converted to biphenyl. When the radiation source was sunlight, only 25% was degraded after a 20-h exposure. But when the sensitizer phenothiazine (5 mM) was added to the solution, photodechlorination of PCB-1254 was complete after 1 h at 350 nm. In addition, when PCB-1254 contaminated soil was heated at about 80 °C in the presence of di-ferf-butyl peroxide, complete dechlorination to biphenyl was observed (Hawari et al., 1992). 

Method laser flash photolysis, if not otherwise mentioned. Solvent 2 1 (v/v) di-ferf-butyl peroxide/benzene or 1 4 (v/v) di-/er/-butyl peroxide/isooctane. 

A) (23), was obtained in an improved yield using the modified literature procedure (28) starting from benzene diazonium chloride (1054) and hydroxymethylene-5-methylcyclohexanone (1055). A biomimetic coupling of l-hydroxy-3-methylcarba-zole (O-demethylmurrayafoline A) (23) by reaction with di-ferf-butyl peroxide l(t-BuO)2] afforded the dimer of O-demethylmurrayafoline A (204). Finally, oxidation of 204 with PCC afforded (+ )-bismurrayaquinone-A (215). The resolution of atropo-enantiomers was achieved by chiral HPLC using Chiracel OF. The assignment of the absolute configuration of the two enantiomers (S)-215 and (f )-215 was achieved by comparison of their theoretical and experimental circular dichroism (CD) spectra (166,167,661) (Scheme 5.164). 

The formal isomerization enthalpies of methyl n-butyl ether to methyl terf-butyl ether and of di-n-butyl ether to n-butyl ferf-butyl ether are about —24kJmoU (Iq) and —26.5 kJmol (g), respectively. From these, and the experimental enthalpy of formation of di-ferf-butyl peroxide, the enthalpies of formation of di-n-butyl peroxide are ca —333 kJmol (Iq) and —288 kJmol (g), wildly divergent from the reported values. 

To examine the extent that cage and entropy had on the original data, activation parameters for the reduction of di-ferf-butyl peroxide were measured from a temperature study using a series of donors. These values are compared with those predicted by the model that accounts for cage and entropy effects and are summarized in Table 5. Examination of the two series of AG appears to account for the original discrepancy in the ET rate... 

They can be handled analogous to thermosetting resins, and thus the use of highly volatile comonomers, such as ethene or prop-ene is prohibitive. Instead, other vinyl monomers are used. A heat curable formulation uses a mixture of tetracyclododecene, 2-norbomene, 5-vinyl-2-norbomene, and divinylbenzene as reactive components (41). The mixture further contains 3,5-di-ferf-butylhy-droxyanisole as antioxidant and a hybrid catalyst system containing a zirconium based metathesis catalyst and a radical catalyst. The metathesis catalyst is benzylidene (l,3-dimesitylimidazolidin-2-yl-idene)(tricyclohexylphosphine)ruthenium dichloride and the radical catalyst is di-ferf-butyl peroxide. 

Alkyl peroxides Di-ferf-butyl peroxide 2,5-Dimethyl-2,5-di-fcrf-butylperoxy-hexyne-3 Diisopropyl peroxide... 

McMillan and Wijnen (30) made a crude estimate for E24a <— 9 dz 2 kcal. per mole in the photolysis of di-ferf-butyl peroxide at 25° and 55°C. from the competition between... 

Gas-phase oxidations of isobutane at 100°C. were carried out with di-ferf-butyl peroxide as initiator as described above. These are summarized in Figure 2, and most are detailed in Table II. Even though conversions were held below 1%, long reaction times (up to 100 hours) were required because of the slow decomposition of the initiator. 

At pressures above 6000 bar, free radical polymerisation sometimes proceeded explosively [1]. The parameters were determined in a batch reactor for thermal runaway polymerisation of acrylonitrile initiated by azoisobutyronitrile, dibenzoyl peroxide or di-ferf-butyl peroxide [2],... 

Adipic acid, 2435 1,4-Benzoquinone, 2207 f 1,3-Butadiene, 1476 Cinnamaldehyde, 3128 Copper iron(II) sulfide, 4263 Dibromomethylborane, 0425 f Di -ferf-butyl peroxide, 3069... 

In another series of experiments, addition of phosphonyl radicals to carbohydrate gem-difluoroenol ethers was investigated as a route to new anomeric carbohydrate difluoromethylene phosphonates 261,262 Phosphonyl radicals could be produced from either diethyl phosphite in the presence of di-ferf-butyl peroxide in refluxing octane, or diethyl(phenylselenyl)phosphonate, on treatment with n-Bu3SnH (plus AIBN) added slowly to a benzene solution under reflux. With the first method,... 

---