Zinc dichromate, alcohol oxidant

Not very many other chromium compounds are suitable for the preparation of carboxylic acids from alcohols. One such compound is zinc dichromate, which oxidizes benzyl alcohol to benzoic acid in 90% yield in dichloromethane solution at room temperature [660]. 

The oxidation of alcohols with metal dichromates, other than sodium or potassium dichromate, has been little explored. Hydrated zinc dichromate (ZnCr207 3H20)367 368a and ferric dichromate [Fe2(Cr207)3],368b—which are very easy to prepare as stable solids—are able to oxidize alcohols in organic solvents.368 Zinc dichromate is particularly efficient in the transformation of a-hydroxyphosphonates into a-ketophosphonates.369... 

Zinc dichromate tiihydrate, ZnCr207<3H20, is obtained as an orange-red solid by adding zinc carbonate to a cold solution of chromium trioxide in dilute sulfuric acid [660]. The applications are oxidations of acetylenes lo a-diketones, of aromatic hydrocarbons to quinones, of alcohols to aldehydes, and of ethers to esters and the oxidative regeneration of carbonyl compounds from their oximes [660]. 

ZINC DICHROMATE (14018-95-2) An oxidizer. Reacts with reducing agents, alcohols, combustible materials, ethers, hydrazines, organic substances, metal powders. 

Both alcohols and aldehydes can be oxidised to carboxylic acids using ruthenium tetroxide an efficient, two-phase (CCl4-aq.NaCl) electro-oxidation method has been developed for the generation of RuO which could be especially useful for oxidations of carbohydrate derivatives, partly protected as acetonides.5 Zinc dichromate... 

HIDROXILAMINA (Spanish) (7803-49-8) A powerful reducing agent. Aqueous solution is a base. Contact with water or steam causes decomposition to ammonium hydroxide, nitrogen, and hydrogen. Contaminants and/or elevated temperatures above (reported at 158°F/70°C and 265°F/129°C) can cause explosive decomposition. Moisture in air or carbon dioxide may cause decomposition. Violent reaction with oxidizers, strong acids, copper(II) sulfate, chromium trioxide, potassium dichromate, phosphorus chlorides, metals calcium, sodium, zinc. Incompatible with carbonyls, pyridine. Forms heat-sensitive explosive mixtures with calcium, zinc powder, and possibly other finely divided metals. Aqueous solution incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, carbonyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, glycols, isocyanates, ketones, nitrates, phenols, pyridine, vinyl acetate. Attacks aluminum, copper, tin, and zinc. 

SODIUM DICHROMATE (10588-01-9) A strong oxidizer. Reacts violently with reducing agents, acids, acetic anhydride, hydrazine, combustible materials, organic substances, metal powders. Reacts with acrolein, antimony trisulfide, antimony tritelluride, arsenic penta-sulfide, 1,1-dichloro-l-nitroethane, 1,3-dichloropropene, diethylamine, fluorine, hydrazine, potassium iodide, sodium tetraborate, sodium tetraborate decahydrate, sodium borohydride, zirconium dusts, j-trioxane. Incompatible with m-bis(trichlormethyl)benzene, hydroxy-lamine. Aqueous solution is caustic incompatible with acids, alcohols, aldehydes, alkylene oxides, cresols, caprolactam solution, epichlorohydrin, organic anhydrides, glycols, maleic anhydride, phenols. Attacks aluminum, copper, brass, bronze, tin, zinc, especially in the presence of moisture. 

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