Dyes, oxidation, hydrogen peroxide

Oxidation of the Dyes with Hydrogen Peroxide with CA[Mn]. 53... 

Nitromethane is active chemically, can have many chemical reactions as a chemical reagent or synthesis intermediate. It also can be used as solvents for cellulose nitrate, cellulose acetate, cellulose acetate, vinyl resin, polyacrylate coating, beeswax, etc. base or other materials can be added into nitromethane for generate explosives when nitromethane is mixed with strong oxidant hydrogen peroxide or N2O4, it can be used as liquid rocket propellants and fuel nitromethane can also be used in medicine, dyes, insecticides, fungicides, stabilizers and surfactants. 

Most often, these determinations rely on the oxidation of an organic compound, usually a dye, by hydrogen peroxide or an oxoanion such as bromate, iodate, or peroxidisulfate or even a chloramine derivative. 

Ichikawa, H. Wada, S. Tatsumi, K. Nitrogenous products obtained by UV-catalyzed oxidation of azo dyes with hydrogen peroxide. Kogai 1990, 25, 145-153 Chem. Abstr. 1990,113, 217356. 

In the present work was investigated the catalytic wet oxidation of reactive dye solutions. Hydrogen peroxide was used as an oxidant and CU/AI2O3 was used as a catalyst. 

Hydrogen peroxide is a colorless, rather unstable liquid, usually sold as a 3% solution in water. It is a powerful oxidizing agent and oxidizes many organic molecules, especially pigments and dyes. Consequently, hydrogen peroxide is an excellent bleach for hair, food, flour, and silk and other textiles. 

Permanent Hair Colorants. Permanent colorants produce hair coloration that lasts until the hair grows out. Color is formed inside the hair by hydrogen peroxide-induced coupling reactions of colorless dye precursors. A hiU range of shades can be obtained with this system and the permanent or oxidative hair colorants are considered to be the most important class of hair dyes. 

Make acid yields coumaUc acid when treated with fuming sulfuric acid (19). Similar treatment of malic acid in the presence of phenol and substituted phenols is a facile method of synthesi2ing coumarins that are substituted in the aromatic nucleus (20,21) (see Coumarin). Similar reactions take place with thiophenol and substituted thiophenols, yielding, among other compounds, a red dye (22) (see Dyes and dye intermediates). Oxidation of an aqueous solution of malic acid with hydrogen peroxide (qv) cataly2ed by ferrous ions yields oxalacetic acid (23). If this oxidation is performed in the presence of chromium, ferric, or titanium ions, or mixtures of these, the product is tartaric acid (24). Chlorals react with malic acid in the presence of sulfuric acid or other acidic catalysts to produce 4-ketodioxolones (25,26). 

More specifically, 2-aminophenol can be detected in solution using an iron(II) sulfate—hydrogen peroxide reagent (94). 3- Aminopheno1 has been analyzed colorimetrically by oxidation in base and subsequent extraction of a violet quinoneimide dye (95). A colorimetric method using... 

Oxidation. Oxidation is one of the main chemical methods to treat and decompose dyes in wastewater. The oxidation agents used ate chlorine, bleach, ozone, hydrogen peroxide, Fenton s reagent, and potassium permanganate. 

The slight excess of sulfite can be left to use as a kind of preservative or be destroyed using oxidizing agents like hydrogen peroxide. One has to be careful in leaving oxidants or reductants in the product. There might be some difficulties when the sulfosuccinate comes in contact with dyes. 

The influence of substituents on the rates of degradation of arylazo reactive dyes based on H acid, caused by the action of hydrogen peroxide in aqueous solution and on cellulose, has been investigated [43]. The results suggested that the oxidative mechanism involves attack of the dissociated form of the o-hydroxyazo grouping by the perhydroxyl radical ion [ OOH]. The mechanism of oxidation of sulphonated amino- and hydroxyarylazo dyes in sodium percarbonate solution at pH 10.6 and various temperatures has also been examined. The initial rate and apparent activation energy of these reactions were determined. The ketohydrazone form of such dyes is more susceptible to attack than the hydroxyazo tautomer [44]. 

This is an alternative method of introducing copper into an o-hydroxyazo dye structure. The azo compound is treated with a copper(II) salt and an oxidant in an aqueous medium at 40-70 °C and pH 4.5-7.0. Sodium peroxide, sodium perborate, hydrogen peroxide or other salts of peroxy acids may be used as oxidants, the function of which is to introduce a second hydroxy group in the o -position [25]. This process is reminiscent of earlier work on Cl Acid Red 14 (5.51 X = H), an o-hydroxyazo dye that will not react with a chromium (III) salt to form a 1 1 complex but will do so by oxidation with an acidified dichromate solution. This oxidation product was later found to be identical with that obtained by conventional reaction of Cl Mordant Black 3 (5.51 X = OH) with a chromium(III) salt [7]. 

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