Benzene peroxide

Benzene peroxide may be more stable in solution since it is protected by the surrounding benzene molecules. The stability of peroxides in the series benzene—naphthalene—anthracene should increase with increasing resonance energy of the aromatic compound. The resonance energy of benzene is 36 kcal mole-1, that of naphthalene is 61 kcal mole-1 and that of anthracene is 83 kcal mole-1. Thus pure anthracene peroxide can be separated and stored for a long time [Refs. 91, 93, 96, 102, 241], whereas benzene peroxide exists only in situ and decomposes in all attempts at separation. The characteristic absorption band of anthracene peroxide also occurs at 2780 A and it may be assumed that the band is characteristic of the peroxides of cyclic hydrocarbons. 

Heat 20 g. of styrene (Section IX,6) with 0 -2 g. of benzoyl peroxide (Section IV,196) on a water bath for 60-90 minutes. A glass-bke polymer (polystyrene) is produced. The polymer is soluble in benzene and in dioxan and can be precipitated from its solution by alcohol. 

The thermal decomposition of thia2ol-2-yl-carbonyl peroxide in benzene, bromobenzene, or cumene affords thiazole together with good yields of 2-arylthiazoles but negligible amounts of esters. Thiazol-4-ylcarbonyl peroxide gives fair yields of 4-arylthiazoles, but the phenyl ester is also a major product in benzene, indicating reactions of both thiazol-4-yl radicals and thiazol-4-carbonyloxy radicals. Thiazole-5-carbonyl peroxide gives... 

Sodium peroxide Glacial acetic acid, acetic anhydride, aniline, benzene, benzaldehyde, carbon di-sulflde, diethyl ether, ethanol or methanol, ethylene glycol, ethyl acetate, furfural, glycerol, metals, methyl acetate, organic matter... 

PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) Di(2-tert-butylperoxyisopropyl)benzene [2781-00-2]... 

Diacyl Peroxides. Table 3 Hsts several commercial diacyl peroxides and their corresponding 10-h half-hfe temperatures, deterrnined in benzene and other solvents (32). Although diacyl peroxides cleave at the oxygen—oxygen bond, decarboxylation can occur, either simultaneously or subsequentiy (eq. 22) ... 

J5)i-tert-55ky. peroxides ate thermally stable organic peroxides, having 10-h HLTs of 110—135°C for acycHc peroxides and 10-h HLTs approaching 200°C for five- to six-membeted cycHc peroxides, eg, 129°C for d4-tert-huty peroxide (in decane) (22), 200°C for 3,3,5,5-tettamethyl-l,2-dioxolane [22431-90-9] (in benzene) (70), and 197°C for 3,3,6,6-tettamethyl-l,2-dioxane (in carbon tetrachloride) (71). 

Diperoxyketals in which the peroxide groups are in a ring are among the most thermally stable organic peroxides, eg, 3,3,6,6,9,9-hexamethyl-l,2,4,5-tetraoxacydononane(10) which has 10-h HLT = 141" C in benzene. 

Benzene reacts with concentrated sulfuric acid and formaldehyde to produce a brown precipitate. A similar reaction occurs with ferrous sulfate and hydrogen peroxide. The resulting brown soHd is dissolved in nitric acid for comparison with color standards. 

Tetracyanoethylene oxide [3189-43-3] (8), oxiranetetracarbonitnle, is the most notable member of the class of oxacyanocarbons (57). It is made by treating TCNE with hydrogen peroxide in acetonitrile. In reactions unprecedented for olefin oxides, it adds to olefins to form 2,2,5,5-tetracyanotetrahydrofuran [3041-31-4] in the case of ethylene, acetylenes, and aromatic hydrocarbons via cleavage of the ring C—C bond. The benzene adduct (9) is 3t ,7t -dihydro-l,l,3,3-phthalantetracarbonitrile [3041-36-9], C22HgN O. 

DMSO, molybdenum peroxide, benzene, reflux, 7-20 h, 60% yield. This method was used to m onoprotect 1,2-diols. The method is not general because oxidation to a-hydroxy ketones and diketones occurs with some substrates. On the basis of the mechanism and the results it would app>ear that overoxidation has a strong conformational dependence. 

Allyl alcohol [107-18-6] M 58.1, b 98°, d4 0,857, no 1.4134. Can be dried with K2CO3 or CaSOa, or by azeotropic distn with benzene followed by distn under nitrogen. It is difficult to obtain peroxide free. Also reflux with magnesium and fractionally distd [Hands and Norman Ind Chem 21 307 1945],... 

Diethylene glycol monoethyl ether [111-90-0] M 134.2, b 201.9", d 0.999, n 1.4273, n 1.4254. Ethylene glycol can be removed by extracting 250g in 750mL of benzene with 5mL portions of water, allowing for phase separation, until successive aqueous portions show the same volume increase. Dried, and freed from peroxides, as described for diethylene glycol mono-n-butyl ether. 

The acetal (b 82.5°) is removed during fractional distn. Traces of benzene, if present, can be removed as the benzene/MeOH azeotrope by distn in the presence of MeOH. Distn from LiAlHa removes aldehydes, peroxides and water. Dioxane can be dried using Linde type 4X molecular sieves. Other purification procedures include distn from excess C2H5MgBr, refluxing with Pb02 to remove peroxides, fractional crystn by partial freezing and the addition of KI to dioxane acidified with aq HCl. Dioxane should be stored out of contact with air, preferably under N2. 

Lauryl peroxide (dodecyl peroxide) [105-74-8] M 398.6, m 53-54°. Crystd from n-hexane or benzene and stored below 0°. Potentially EXPLOSIVE. 

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