Di-t-butyl peroxide

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-t-butyl peroxide Figure 7.13). 

A teehnique that is a convenient source of radieals for study by EPR involves photolysis of a mixture of di-t-butyl peroxide, triethylsilane, and the alkyl bromide corresponding to the radieal to be studied. Photolysis of the peroxide gives t-butoxy radieals, whieh selectively abstract hydrogen from the silane. This reactive silicon radieal in turn abstracts bromine, generating the alkyl radieal at a steady-state eoncentration suitable for EPR study. 

Hydroxy-20-ketones via Ethoxyethynyl Carbinols A solution of 3, 17/ -dihydroxy-21-ethoxy-17a-pregn-5-en-20-yne 3-acetate (5 g) in ethanethiol (10 g) to which di-t-butyl peroxide (0.95 g) has been added is refluxed for 4 hr... 

The most common way to generate sulfonyl radicals for spectroscopic studies has been the photolysis of solutions containing di-t-butyl peroxide, triethylsilane and the corresponding sulfonyl chloride in a variety of solvents (equations 4-6). The slowest step in this sequence is the reaction between t-butoxyl radicals and triethylsilane (ks = 5.3 x 106m 1s-1)26 since that for chlorine abstraction (equation 6) is extremely efficient (cf. Table 4). 

In order to bring about crosslinking of polyesters with styrene one of two types of initiator systems is used, which differ in the temperature at which they are effective. For curing at elevated temperatures, peroxides are used which decompose thermally to yield free radicals. Among those peroxides employed are benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-t-butyl peroxide, and dodecyl peroxide. Mixtures of polyester prepolymer, styrene, and such initiators are reasonably stable at room temperatures but undergo fairly rapid crosslinking at temperatures between 70 °C and 150 °C, depending on which particular peroxide is used. 

Pyrolysis of the phosphorodichloridothioate (59) at 550 °C gives mainly dibenzothiophen and a smaller amount of the cyclic phosphonochlorido-thioate (60). Thermal decomposition of di-t-butyl peroxide in triethyl phosphate gives rise to diethyl methyl phosphate in a reaction which may be interpreted as resulting from attack of methyl radical on the phosphoryl oxygen. An extension of this mechanism accounts for the formation of (61) from tri-isopropyl phosphate under the same conditions. 

Further investigations for the radical isomerisation of hydro-spirophosphoranes have shown that, on heating with di-t-butyl peroxide in benzene, phosphoranes (66) and (67) are transformed into (68) and (69) respectively93. The proposed mechanism, as written for (67), proceeds through the phosphoranyl radical (70) which rearranges to (71) which in turn reacts with (67) to form (69) and (70) in the propagation step. 

LOAD REACTION WITH 5 GRAMS DI-T-BUTYL PEROXIDE WAIT 60 MINUTES ... 

Ethylene-propylene and silicone rubbers are crosslinked by compounding with a peroxide such as dicumyl peroxide or di-t-butyl peroxide and then heating the mixture. Peroxide cross-linking involves the formation of polymer radicals via hydrogen abstraction by the peroxy radicals formed from the decomposition of the peroxide. Crosslinks are formed by coupling of the polymer radicals... 

The data of the table are of the decomposition of di-t-butyl peroxide to acetone and ethane at 188 C in a tubular flow reactor of 82.4 cc volume. The concentrations are in mol/liter and flow rate is in cc/sec. A carrier gas was used, and any volume change resulting from the reaction may be taken negligible. Find the rate equation. 

The decomposition of gaseous di-t-butyl peroxide in the presence of a nitrogen carrier gas (D) has been studied near 481 K in a CSTR (Mulcahy Williams, Austral J Chem 14 534, 1961). 

The value obtained (8 x 10 1 mol-1 s-1 in di-t-butyl peroxide at 40°) is in fair agreement with that (1.5 x 10 ) reported by Janzen and Evans (1973) both figures seem surprisingly large in view of the rapid reversal of the process (, = 0.14 s"1 at 40°). 

Primary aliphatic or aromatic amines RNH2 are converted into carbamates RNHCC Et on treatment with carbon monoxide and di-t-butyl peroxide in the presence of palladium(II) chloride and copper(II) chloride357. Carbamic esters 304 and 305 are also obtained from aliphatic amines and ortho carbonates (R30)4C358. Vinyl carbamates R12NC02CH=CHR2 are produced from secondary aliphatic amines, acetylenes R2C=CH (R2 = Bu or Ph) and carbon dioxide in the presence of ruthenium(III) chloride359. 

DI-t-BUTYL PEROXIDE DI-n-BUTYL SULFONE DIETHYLENE GLYCOL DIETHYL ETHER... 

The various initiators are used at different temperatures depending on their rates of decomposition. Thus azobisisobutyronitrile (AIBN) is commonly used at 50-70°C, acetyl peroxide at 70-90°C, benzoyl peroxide at 80-95°C, and dicumyl or di-t-butyl peroxide at 120-140°C. The value of the decomposition rate constant kj varies in the range... 

Consider the polymerization of styrene initiated by di-t-butyl peroxide at 60°C. For a solution of 0.01 M peroxide and 1.0 M styrene in benzene, the initial rates of initiation and polymerization are 4.0 x 10 11 and 1.5 x 10 7 mol L 1 s 1, respectively. Calculate the values of (jkj), the initial kinetic chain length, and the initial degree of polymerization. Indicate how often on the average chain transfer occurs per each initiating radical from the peroxide. What is the breadth of the molecular weight distribution that is expected, that is, what is the value of Xw/Xnl Use the following chain-transfer constants ... 

The addition of phosphine to olefins provides today a generally applicable method for the syntheses of organophosphines. Stiles, Rust and Vaughan were the first to study the reaction systematically. It is catalysed by organic peroxides such as, for example, di-t-butyl peroxide, by a, a -azobis-isobutyro-nitrile by other free radical sources or by exposing the reaction mixture to UV- or X-radiation. The PHj radicals, produced according to Eq. (77), react further with olefins thus producing PH2 radicals continually. 

Oxidation of 1,4-thioxane by BTSP and /-butyl(trimcthylsilyl) peroxide in CHC13 at 25 °C is compared to those of the same substrate by the more common oxidants, t-butyl hydroperoxide and di-t-butyl peroxide, in the same solvent. The two silyl peroxides give similar oxidations rates, which are over 50 times higher than that measured for t-BuOOH, while -Bu202 is almost unreactive under the conditions adopted. Oxidation... 

Di -t-butyl Peroxide is a very active high-temp polymerization catalyst. Vaughan ... 

A typical unimolecular reaction is the decomposition of organic peroxides for which always positive activation volumes of up to 15 cm3/mol have been observed. The decomposition of di(t-butyl)peroxide, an effective initiator for the high pressure polymerisation of ethylene, into two t-butoxyradicals, exhibits a positive activation volume of 13 cm3/mol (Table 3.2-1, a). When new bonds are formed as in the association... 

The half-life time, Tm, of decomposition of di(t-butyl)peroxide at a temperature of 463 K and ambient pressure is 50 s. One may calculate the rate constant and the half-life time for decomposition at 300 MPa and the same temperature, when the activation volume is Av = +13 cm3 mol"1. 

PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) Di-t-butyl peroxide [110-05-4]... 

Trimethylsilyloxyethylene, 274, 299 3-Trimethylsilyl-l-propyne, 329 Trimethylsilyl trifluoromethanesul-fonate, 118, 149, 187, 321, 329 Trimethyl(trichloromethyl)silane, 336 Triphenylsilane, 334 Triphenylsilane-Di-t-butyl peroxide, 334... 

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