Oxidation benzenediols

Section 24 14 Oxidation of 1 2 and 1 4 benzenediols gives colored compounds known as qumones... 

Our recent studies on effective bromination and oxidation using benzyltrimethylammonium tribromide (BTMA Br3), stable solid, are described. Those involve electrophilic bromination of aromatic compounds such as phenols, aromatic amines, aromatic ethers, acetanilides, arenes, and thiophene, a-bromination of arenes and acetophenones, and also bromo-addition to alkenes by the use of BTMA Br3. Furthermore, oxidation of alcohols, ethers, 1,4-benzenediols, hindered phenols, primary amines, hydrazo compounds, sulfides, and thiols, haloform reaction of methylketones, N-bromination of amides, Hofmann degradation of amides, and preparation of acylureas and carbamates by the use of BTMA Br3 are also presented. 

C.-E. Lin, Y.-T. Chen and T.-Z. Wang, Separation of benzenediamines, benzenediols and aminophenols in oxidative hair dyes by micellar electrokinetic chromatography using cationic surfactants. J. Chromatogr.A, 837 (1999) 241-252. 

Aluminium, 0048 Ammonium phosphinate, 4554 Barium phosphinate, 0210 f Benzaldehyde, 2731 1,4-Benzenediol, 2333 Bis(hydrazine)tin(II) chloride, 4070 Calcium acetylide, 0585 Calcium phosphinate, 3931 Chromium(II) chloride, 4052 Chromium(II) oxide, 4241 Chromium(II) sulfate, 4244 Copper(I) bromide, 0265 Diacetatotetraaquocobalt, 1780 Diisobutylaluminium hydride, 3082 f 1,2-Dimethylhydrazine, 0955... 

Several products were also detected in base-degraded D-fructose solution acetoin (3-hydroxy-2-butanone 62), l-hydroxy-2-butanone, and 4-hydroxy-2-butanone. Three benzoquinones were found in the product mixture after sucrose had been heated at 110° in 5% NaOH these were 2-methylbenzoquinone, 2,3,5-trimethylbenzoquinone, and 2,5-dimethyl-benzoquinone (2,5-dimethyl-2,5-cyclohexadiene-l,4-dione 61). Compound 62 is of considerable interest, as 62 and butanedione (biacetyl 60) are involved in the formation of 61 and 2,5-dimethyl-l,4-benzenediol (63) by a reduction-oxidation pathway. This mechanism, shown in Scheme 10, will be discussed in a following section, as it has been proposed from results obtained from cellulose. 

A values have been obtained for oxidation of benzenediols by [Fe(bipy)(CN)4], including the effect of pH, i.e., of protonation of the iron(III) complex, and the kinetics of [Fe(phen)(CN)4] oxidation of catechol and of 4-butylcatechol reported. Redox potentials of [Fe(bipy)2(CFQ7] and of [Fe(bipy)(CN)4] are available. The self-exchange rate constant for [Fe(phen)2(CN)2] has been estimated from kinetic data for electron transfer reactions involving, inter alios, catechol and hydroquinone as 2.8 2.5 x 10 dm moF s (in dimethyl sulfoxide). 

P-Azo-[2-methyl-1,2-dicarbadecaborane( 14)], 2624 2-Azoxyanisole, 3653 1,4-Benzenediol-oxygen complex, 2334 Benzeneperoxy sulfonic acid, 2341 Benzeneseleninic acid, 2335 Benzeneseleninic anhydride, 3495 Benzenethiol, 2344 2,2 -Bi-l,3-dithiole, 2215 2,2 -Bipyridyl 1-oxide, 3258 Bis(cyclopentadienyl)lead, 3294 Bis-A(imidosulfurdiiluoridato)mercury, 4342 Bismuth trisulfide, 0234... 

Phenols are more easily oxidized than alcohols, and a large number of inorganic oxidizing agents have been used for this purpose. The phenol oxidations that are of the most use to the organic chemist are those involving derivatives of 1,2-benzenediol (pyrocate-chol) and 1,4-benzenediol (hydroquinone). Oxidation of compounds of this type with silver oxide or with chromic acid yields conjugated dicarbonyl compounds called quinones. 

All are exceptionally reactive towards electrophilic reagents, particularly in alkaline solution, and all are readily oxidized. The 1,2- and 1,4-benzenediols, but not 1,3-benzenediol, are oxidized to quinones ... 

The reactive vinyl monomers usually are stabilized against polymerization, while in storage, by addition of 0.1 to 1% of an inhibitor. 1,4-Benzenediol (hydroquinone), 2,6-di-terf-butyl-4-methylbenzenol, and 4- ert-butyl-l,2-ben-zenediol are used for this purpose. These substances are especially effective at scavenging RO- radicals, which are formed by oxidation of the monomer with atmospheric oxygen. 

Aluminium, 0048 Ammonium phosphinate, 4549 Barium phosphinate, 0210 f Benzaldehyde, 2727 1,4-Benzenediol, 2326 Bis(hydrazine)tin(II) chloride, 4064 Calcium acetylide, 0582 Calcium phosphinate, 3925 Chromium(II) chloride, 4046 Chromium(II) oxide, 4235 Chromium(II) sulfate, 4238 Copper(I) bromide, 0264 Diacetatotetraaquocobalt, 1774 Diisobutylaluminium hydride, 3076 f 1,2-Dimethylhydrazine, 0951 1,2-Diphenylhydrazine, 3511 Dipotassium phosphinate, 4425 f Ethanedial, 0719 f Formaldehyde, 0415 Formic acid, 0417 Gallium(I) oxide, 4405 Glucose, 2513 f Hydrazine, 4515 Hydroxylamine, 4493 Hydroxylaminium phosphinate, 4550 Hyponitrous acid, 4464 Iron(II) chloride, 4055 Iron(II) hydroxide, 4386 Iron(II) sulfate, 4393 Fead(II) phosphinate, 4526 Fead(II) phosphite, 4530 Fithium dithionite, 4682 Magnesium, 4685 Magnesium phosphinate, 4512 Manganese(II) phosphinate, 4514 f Methylhydrazine, 0500 Phenylhydrazine, 2366 Phosphinic acid, 4498 Phosphonic acid, 4499 Phosphonium iodide, 4510 Potassium, 4640 Potassium hypoborate, 0163... 

SYNS o-BENZENEDIOL 1,2-BENZENEDIOL CATECHIN C.I. 76500 C.I. OXIDATION BASE 26 o-DIHYDROXYBENZENE 1,2-DIHYDROXYBENZENE... 

Tyrosinase shows no activity for the oxidation of p- and m-benzenediols. Laccase, which catalyzes the oxidation of o-, m-, and p-benzenediols to the corresponding o-, ra-, and p-quinones, is used for the detection of these benzenediols. Thus, coinunobihzation of tyrosinase and laccase allows the detection of several phenohc compoimds [llj. Several authors have presented a large number of research and review papers on the structmal and kinetic aspects of the enzyme tyrosinase [ 12-14). 

BENZENEDIOL (120-80-9) C HsOj Combustible solid (flashpoint 260°F/127°C cc autoignition tenq) 915°F/510°C Fire Rating 1). Dust and powder can form explosive mixture with air. A reducing agent. Violent reaction with strong oxidizers concentrated nitric acid acid chlorides acid anhydrides. Flow or agitation of substance... 

BENZENEDIOL (108-46-3) Combustible solid (flash point 261°F/127°C cc). Dust or powder forms explosive mixture with air. Violent reaction with strong oxidizers, nitric acid. Incompatible with acetanilide, alkalis, ammonia, amino compounds, antipyrine, camphor, ferric salts, lead diacetate, menthol, spirit nitrous ether, urethane. May accumulate static electrical charges, and may cause ignition of its dust. 

BENZENEDIOL (123-31-9) Combustible solid (flash point 329°F/165°C cc). A reducing agent. Violent reaction with strong oxidizers, caustics, sodium hydroxide. May explode on contact with oxygen gas. May be oxidized to quinone at room temperatures in the... 

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