Sulfurous acid, oxidation

Since the FeCp(C6H6)+ unit is robust towards oxidation even in concentrated sulfuric acid, oxidation of alkyl substituents upon boiling in aqueous KMn04 solution can be achieved and leads to carboxylic substituents. The mesitylene complex can be oxidized to the mono-, di-, or tri-carboxylic add depending upon the reaction conditions. In the latter case, the decomplexed trimesic acid is obtained [106, 107] Scheme XXII ... 

Toluidines 2,4,6-Trinitrotoluene 1,3,5-Trioxane Urea Vinylidene chloride Nitric acid Sodium dichromate, sulfuric acid Oxidizing materials, acids Sodium nitrite, phosphorus pentachloride Chlorosulfonic acid, nitric acid, oleum... 

Modern methods of manufacturing this probably oldest representative among synthetic organic pigments involve dissolving aniline in strong sulfuric acid. Oxidation is achieved with sodium dichromate in the presence of a copper salt or one of the above-mentioned oxidation catalysts. Oxidation with sodium chlorate initially affords an indamine polymer (pernigraniline) ... 

In dilute aqueous solution, sulfuric acid is a nonoxidizing acid. However, when concentrated and hot, it is an oxidizing agent. Thus, hot and concentrated sulfuric acid oxidizes copper to Cu2+, hherating sulfur dioxide. The net ionic equation is ... 

Simdar reactions occur with zinc, magnesium, aluminum, and iron. Concentrated sulfuric acid oxidizes iodide to iodine and bromide to bromine ... 

Methylcarbazole reacted with 2,6-dimethyl-4-pyrone in the presence of phosphorus oxychloride generating the pyrylium salt 170. Xanthydrol and thiaxanthydrol condensed with carbazole and 9-methylcarbazole under acid catalysis and sulfuric acid oxidation to give the colored salts 171 (X = O or S) the process has been used for the colorimetric determination of carbazole. ... 

From Group 15 to Group 16. non-metallic behaviour takes over completely with no positive ions being stable. The + 6 state of sulfur is seen to have very poor oxidizing properties, and it is only in its concentrated form, and when hot, that sulfuric(VI) acid is a good oxidant. Hot concentrated sulfuric acid oxidizes metallic copper and is reduced to sulfur dioxide. The relative stabilities of the Se species with positive oxidation stales are considerably less than their S or Te counterparts, another example of the effect of the 3d contraction. 

Ethanol and Sulfuric Acid. Oxidation of ethanol with acid dichromate may result in minor explosion.4... 

In order to elucidate how the composite material mechanical parameters depend on MWNT surface groups composition the samples of MWNT were subjected to anode oxidation (200 A.h/kg) in aqueous sulfuric acid. Oxidized product was washed with water to pH=6-7, dried and disintegrated. A part of this... 

They also found that, depending on the electrolyte composition, the organics were oxidized on both the electrode surface by reaction with hydroxyl radicals and in the bulk of the solution by inorganic oxidants electrogenerated on the BDD anodes, such as peroxodisulfuric acid from sulfuric acid oxidation ... 

Oxidation. Very vigorous oxidation of the thiophene ring results in breakdown to maleic and oxalic acids and ring sulfur is oxidized to sulfuric acid. Oxidation of thiophene with peracid under carefully controlled conditions gives a mixture of thiophene sulfoxide 54 and 2-hydroxythiophene sulfoxide 56. These compounds can be trapped by addition to benzoquinone to give ultimately naphthoquinones 55 and 57. Dimerization via a DielsAlder reaction gives 58. 

Another type of analytical application of sulfuric acid oxidation has been developed recently, based on the intense fluorescence which appears when the sulfuric solutions containing oxidized pheno-thiazine derivatives are diluted with dimethyl sulfoxide. It has been shown that concentrations as low as 0.01 /xg/ml may be detected this way and that substituents in position 2 decrease the intensity of the fluorescence to a greater extent than side chains at position 10.1 1... 

Sulfuric acid is a moderately strong oxidizing agent, especially at high temperatures. Hot concentrated sulfuric acid oxidizes bromide or iodide ions to elemental bromine or iodine. For example,... 

Oxidations of hydroxy ketones to diketones occur frequently in steroidal alcohols. If the alcoholic group, usually secondary, is remote enough from the keto group, its oxidation takes place independently and is achieved by the same reagents that are used for the oxidation of alcohols. A solution of chromium trioxide in aqueous sulfuric acid oxidizes 5-pregnen-3p-ol-20-one in acetone solution at room temperature within 2-5 min to 5-pregnen-3,20-dione in 90% yield [579]. Similarly, lip-hydroxytestosterone 17-acetate is transformed by chromium trioxide in 80% acetic acid at room temperature in 30 min into 11-ketotestosterone 17-acetate in 92% yield [807]. 

Physical properties Silver-white, liquid metal in the solid state, mercury is ductile and malleable and can be cut with a knife Chemical properties Combines readily with sulfur at normal temperatures reacts with nitric acid and hot sulfuric acid oxidizes to form mercury(ll) oxide upon heating in air... 

Several commercial evidential breath alcohol measurement devices are available. The principle of measurement is either infrared absorption spectrometry (most common), dichromate-sulfuric acid oxidation-reduction (photometric), GC (flame ionization or thermal conductivity detection), electrochemical oxidation (fuel cell), or metal-oxide semiconductor sensors. A list has been published of DOT-approved breath alcohol devices.Some of these devices are approved for screening only. In this case, the second or confirmatory breath alcohol determination must be performed with an approved evidential breath alcohol analyzer. Breath alcohol devices may also be used for the medical evaluation of patients at the point of care (e.g., emergency department). A Fourier transform infrared point-of-care breath analyzer capable of measurement of... 

Derivation Reaction of acetone cyanohydrin and dilute sulfuric acid oxidation of isobutylene. 

A successful bromination with bromine of A-aminopyrazoles at position 4 (88CPB3838) and 9-aminoxanthines at position 8 was reported (89KGS95). 7-Aminotheophiline is brominated at position 8 in moderate yield only in acetic acid. Under the action of bromine in water or HNO3 in sulfuric acid, oxidation of the A-amino group occurs (89KGS95). 9-Aminoxanthines under the action of nitric acid form nitrates, which do not undergo nitration (89KGS95). 

With tertiary phosphines l-aryl-2-azidomethylbenzimidazoles form condensed derivatives (Scheme 80) <89T1823>. Mixed nitric and sulfuric acids oxidize the Mannich base, 2,4,5-tris(di-methylaminomethyl)imidazole, to imidazole-4,5-dicarboxylic acid <89CHE165>. 

Oleum (fuming sulfuric acid) Oxidation catalyst made from porcelain Porchloric acid Peroxides, inorganic Phosphates, except defluorinated and ammoniated... 

Concentrated sulfuric acid oxidizes nonmetals. For example, it oxidizes carbon to carbon dioxide and sulfur to sulfur dioxide ... 

Concentrated sulfuric acid oxidizes the metal to Fe, but concentrated nitric acid renders the metal passive by forming a thin layer of Fe304 over the surface. One of the best-known reactions of iron is rust formation (see Section 19.7). The two oxidation states of iron are -1-2 and -1-3. Iron(II) compounds include FeO (black), FeS04 7H2O (green), FeCl2 (yellow), and FeS (black). In the presence of oxygen, Fe ions in solution are readily oxidized to Fe ions. Iron(III) oxide is reddish brown, and iron(III) chloride is brownish black. 

NaHS04. The HCl gas escapes, driving the equilibrium to the right. 21.84 25.3 L. 21.86 Sulfuric acid oxidizes sodium bro-... 

Ruhr-Zinc GmbH (the first zinc smelter in Europe) defined a concept, which eliminated these two problems (Veltman and Weitz 1982). It used sulfuric acid, oxidizing pressure-leaching of zinc sulfide, with which Fe(III) ions take over a catalytic role by constant oxidation with oxygen. The resulting elementary sulfur can be produced in either liquid or solid form by further pressure-leaching of the residues. Pyrite (FeS) can also be used for meeting the sulfuric... 

Knowledge of how aluminum chloride oxidizes aromatics to cation radicals is practically non-existent. At one time it seemed that a nitro compound was a necessary co-acceptor (Buck et al., 1960) and that, whereas with mononuclear alkylaromatics, the Lewis acid-nitro compound pair formed only charge transfer complexes (Brown and Grayson, 1953), complete electron transfer occurred with more easily oxidized aromatics. But, cation-radical formation from perylene, anthracene, and chrysene was found to occur in carbon disulfide, chloroform, and benzene solutions, too (Rooney and Pink, 1961) and even occurs on warming anthracene and naphthacene with solid aluminum chloride (Sato and Aoyama, 1973). There is no doubt that a nitro compound enhances electron transfer, however (Sullivan and Norman, 1972). Cation radical formation in AlCl3-nitromethane has been estimated as approximately 100% as compared with 1% in sulfuric acid oxidation of dialkoxybenzenes (Forbes and Sullivan, 1966). Unfortunately, aluminum halide salts have not been isolated and, therefore, even the beginnings of analytical data have yet to be collected. There is no definite knowledge of either the nature of the counter ion or the fate of the electrons in these cation-radical formations. 

Uranium ore is typically mined or leached in situ. For the mined ore, the raw material is milled to produce a high surface area slurry, which is then treated with H2SO4. The sulfuric acid oxidizes the uranium to the soluble hexavalent state. The addition of base to the solution precipitates an oxide of uranium known as yellowcake , UsOs. A similar process is used for the in situ leaching of uranium ore except that the initial treatment is performed on bores with a slightly acidic and high oxygenated aqueous solution that is raised to the surface and allowed to go through an extraction process to remove the uranium. 

The sulfuric acid oxidizes fhe tartaric first into glycol aldehyde and formic acid and finally fhe glycol aldehyde into glyoxylic acid (Figure 3.33.4). 

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