Tert Butyl peroxide

FLUORINECOMPOUNDS,ORGANIC - FLUORINATED ALIPHATIC COMPOUNDS] (Vol 11) Perfluoro-di-tert-butyl peroxide [2684285-3]... 

Di-tert-butyl peroxide (tert-butyl peroxide) [110-05-4] M 146.2, d 0.794, n 1.389. Washed with aqueous AgN03 to remove olefinic impurities, water and dried (MgS04). Freed from /cr/-butyl hydroperoxide by passage through an alumina column [Jackson et al. J Am Chem Soc 107 208 1985], and if necessary two high vacuum distns from room temp to a liquid-air trap [Offenbach and Tobolsky J Am Chem Soc 79 278 1957]. The necessary protection from EXPLOSION should be used. 

High molecular weight polymers are produced by an adiabatic bulk polymerisation process ° using di-tert-butyl peroxide (0.02%) and 2,2 -azo-bisdi-isobutyronitrile (0.01%) as initiators and pressurised with N2. Heating to 80-90°C causes an onset of polymerisation and a rapid increase in temperature. After the maximum temperature has been reached the mass is allowed to cool under pressure. A typical current commercial material (Luvican M.170) has a A -value of about 70 (as assessed in a 1% tetrahydrofuran solution). 

For the above scales, eye protection should be worn and work should be undertaken in a standard fume-cupboard behind a well-anchored polycarbonate screen. It is advisable to wear a protective apron and hand protection whether leather gauntlets or tongs should be used will be dictated by circumstances. Such measures are recommended but it should be ensured that they do not precipitate a hazard as a result of loss of tactile sensitivity (e.g. dropping a flask, overtightening clamps, exerting excessive pressure when assembling apparatus). The material of gloves needs consideration. (PVC but not rubber is suitable for tert-butyl peroxide.)... 

DTBP see DI-tert-BUTYL PEROXIDE DURSBAN see CHLORPYRIFOS... 

The reaction of benzyl radicals wdth several heterocyclic compounds W as more extensively studied by Waters and Watson, " - who generated benzyl radicals by decomposing di-tert-butyl peroxide in boiling toluene. The products of the reaction with acridine, 5-phenyl-acridine, 1 2- and 3 4-benzacridine, and phenazine were studied. Acridine gives a mixture of 9-benzylacridine (17%) (28) and 5,10-dibenzylacridan (18%) (29) but ho biacridan, w hereas anthracene gives a mixture of 9,10-dibenzyl-9,10-dihydroanthracene and 9,9 -dibenzyl-9,9, 10,10 -tetrahydrobianthryl. This indicates that initial addition must occur at the meso-carbon and not at the nitrogen atom. (Similar conclusions were reached on the basis of methylations discussed in Section III,C.) That this is the position of attack is further supported by the fact that the reaction of benzyl radicals with 5-... 

Auch einfache aliphatische Lactone werden radikalisch nach Initiierung mit y-Strahlen oder mit photoinduzierter Zersetzung von Di-tert.-butyl-peroxid durch Trichlor-silicium-hydrid zu cyclischen Athern reduziert11 ... 

Atheraus Lactonen allgemeine Arbeitsvorschrift1 4 mMol Trichlor-siliciumhydrid und 1 mMol Laeton bzw. das Gemisch von 1 mMol Laeton und 0,05 Mol Di-tert.-butyl-peroxid werden in ciner evakuierten Glasrohre durch y-Strahlen aus einer "Co-Quelle bzw. mit U V-Licht aus einer Quecksilber-Mitteldruck-Lampe bei 20° be-strahlt. 

Note The contrast between the colored zones and the layer background can be improved by warming the chromatogram gently [4]. Di-tert-butyl peroxide does not react [3]. N,N,N, N -tetramethyl-p-phenylenediamine (q.v.) can also be used instead of N,N-DPDD for the detection of peroxides [3]. The spray solution for peroxides gradually turns dark red in color but it still retains its ability to react for several weeks [4]. 

Di-terf-butyl malonate, 59, 66 Di-tert-butyl peroxide, 55, 61... 

There is a similar situation related to substitution in a nearby unstable site. Thus tert-butyl peroxide can be handled whereas butyl peroxide cannot. These are static effects, not to be confused with mass effects (see later). 

Preparing tert-butyl peroxide by the effect of 50% hydrogen peroxide in the presence of 78% sulphuric acid has led to numerous accidents. They were due to the high exothermicity of the reaction causing a temperature rise and leading to the explosive decomposition of the peroxide formed, if the temperature rise is badly monitored. 

Experimental set up as in section a). Alkoxy radicals were produced by photolysis of di-tert.-butyl peroxide (2 Mol/1). The build up of hydroperoxide concentration was measured by a modified version of the iodometric method used by Carlsson and Wiles—. 

Biesenberger, J. A. et al., Polym. Eng. Sci., 1976, 16, 101-116 The parameters were determined in a batch reactor for thermal runaway polymerisation of styrene, initiated by azoisibutyronitrile, dibenzoyl peroxide or di-tert-butyl peroxide. 

Two types of addition to pyrimidine bases appear to exist. The first, the formation of pyrimidine photohydrates, has been the subject of a detailed review.251 Results suggest that two reactive species may be involved in the photohydration of 1,3-dimethyluracil.252 A recent example of this type of addition is to be found in 6-azacytosine (308) which forms a photohydration product (309) analogous to that found in cytosine.253 The second type of addition proceeds via radical intermediates and is illustrated by the addition of propan-2-ol to the trimethylcytosine 310 to give the alcohol 311 and the dihydro derivative 312.254 The same adduct is formed by a di-tert-butyl peroxide-initiated free radical reaction. Numerous other photoreactions involving the formation by hydrogen abstraction of hydroxyalkyl radicals and their subsequent addition to heterocycles have been reported. Systems studied include 3-aminopyrido[4,3-c]us-triazine,255 02,2 -anhydrouri-dine,256 and sym-triazolo[4,3-fe]pyridazine.257 The photoaddition of alcohols to purines is also a well-documented transformation. The stereospecific addition of methanol to the purine 313, for example, is an important step in the synthesis of coformycin.258 These reactions are frequently more... 

DHBP 2,5-Dimethylhexane-2,5-di-tert.-butyl peroxide 0.88 (liquid) 1.50 (paste powder)... 

From an experimental viewpoint, there are strong indications that the reduction of di-tert-butyl peroxide proceeds with a significant degree of non-adiabaticity.201... 

Another differential reaction is copolymerization. An equi-molar mixture of styrene and methyl methacrylate gives copolymers of different composition depending on the initiator. The radical chains started by benzoyl peroxide are 51 % polystyrene, the cationic chains from stannic chloride or boron trifluoride etherate are 100% polystyrene, and the anionic chains from sodium or potassium are more than 99 % polymethyl methacrylate.444 The radicals attack either monomer indiscriminately, the carbanions prefer methyl methacrylate and the carbonium ions prefer styrene. As can be seen from the data of Table XIV, the reactivity of a radical varies considerably with its structure, and it is worth considering whether this variability would be enough to make a radical derived from sodium or potassium give 99 % polymethyl methacrylate.446 If so, the alkali metal intitiated polymerization would not need to be a carbanionic chain reaction. However, the polymer initiated by triphenylmethyl sodium is also about 99% polymethyl methacrylate, whereas tert-butyl peroxide and >-chlorobenzoyl peroxide give 49 to 51 % styrene in the initial polymer.445... 

The laser flash photolysis of aromatic diisocyanate based polyurethanes in solution provides evidence for a dual mechanism for photodegradation. One of the processes, an N-C bond cleavage, is common to both TDI (toluene diisocyanate) and MDI (methylene 4,4 -diphenyldiisocyanate) based polyurethanes. The second process, exclusive to MDI based polyurethanes, involves formation of a substituted diphenylmethyl radical. The diphenylmethyl radical, which readily reacts with oxygen, is generated either by direct excitation (248 nm) or indirectly by reaction with a tert-butoxy radical produced upon excitation of tert-butyl peroxide at 351 nm. 

Materials. Methylene 4,4 -diphenyldiisocyanate (MDI, Mobay) was recrystallized from cyclohexane. Toluenediisocyanate (TDI— represents mixture of 2,4- and 2,6-isomers in 80/20 ratio), p-toluidine (Aldrich) and aniline (Aldrich) were purified by vacuum distillation before use. Diphenylmethane, tert-butyl peroxide (TBP), 4-bromoaniline, butyl lithium in hexane, and ethyl chloroformate, were obtained from Aldrich and used as received. Spectrograde tetrahydrofuran (THF) and benzene from Burdick and Jackson were used as received. Poly(tetramethylene ether glycol) with MW 1000 was obtained from polysciences and dehydrated under a rough vacuum at 50 °C for 24 h. 

Laser Flash Photolysis at 351 nm of tert-Butyl Peroxide/Benzene Solutions Containing MDI-PUE and Model Compounds. Photolysis of tert-butyl peroxide (TBP) results in a highly efficient production of tert-butoxy radicals. It has recently been shown (15) that tert-butoxy radicals generated by the laser flash photolysis of TBP can rapidly extract hydrogen atoms from appropriate substrates such as aniline and diphenylamine (Scheme III). 

For MDI based polyurethanes we have provided evidence for formation of a diphenylmethyl radical by direct excitation (248 nm) of the carbamate moiety as well as hydrogen abstraction by a tert-butoxy radical which is produced by excitation (351 nm) of tert-butyl peroxide. The diphenylmethyl radical readily reacts with oxygen. A proposed mechanism which accounts for the production (direct or indirect) and subsequent reaction with oxygen of the diphenylmethyl radical is shown in Scheme IV. The hydrogen peroxide product depicted in Scheme IV has been previously identified by FT-IR (7) we have simply provided a plausible mechanism for its formation. 

Synthetic applications of carbon radical additions to allenes cover aspects of polymerization, selective 1 1 adduct formation and homolytic substitutions. If heated in the presence of, e.g., di-tert-butyl peroxide (DTBP), homopolymerization of phenylal-lene is observed to provide products with an average molecular weight of 2000 (not shown) [58]. IR and 1H NMR spectroscopic analyses of such macromolecules point to the preferential carbon radical addition to CY and hence selective polymerization across the 2,3-double bond of the cumulene. Since one of the olefinic jr-bonds from the monomer is retained, the polymer consists of styrene-like subunits and may be... 

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