Acidic potassium dichromate

Of little use commercially except as a route to anthraquinone. For this purpose it is oxidized with acid potassium dichromate solution, or better, by a catalytic air oxidation at 180-280 C, using vanadates or other metal oxide catalysts. 

Soil organic carbon concentration was determined by the sulfuric acid-potassium dichromate method (Kalembasa and Jenkinson 1973) at the Soil Chemistry Laboratory of South China Institute of Botany, CAS. Results... 

The chemical method for the determination of the chemical oxygen demand of non-saline waters involves oxidation of the organic matter with an excess of standard acidic potassium dichromate in the presence of silver sulfate catalyst followed by estimation of unused dichromate by titration with ferrous ammonium sulfate. Unfortunately, in this method, the high concentrations of sodium chloride present in sea water react with potassium dichromate producing chlorine ... 

In the Breathalyzer test, the subject blows into a tube connected to a vial. The exhaled air collects in the vial, which already contains a mixture of sulfuric acid, potassium dichromate, water, and the catalyst silver nitrate. The alcohol reacts with the dichromate ion in the following redox reaction. 

Wet oxidation Several types of liquid-phase oxidizing agents, such as nitric acid, acidic potassium permanganate, acidic potassium dichromate, dichromate permanganate, hydrogen peroxide, ammonium bicarbonate and potassium persulfate, have... 

Hot acidic potassium dichromate (K2Cr20. ) u Chromium trioxide (Cr03) in sulfuric acid (H2SO (Jones rec ent) u Hot basic permanganate followed by acidification... 

Certification and Use of Acidic Potassium Dichromate Solution as an Ultraviolet Absorbance Standard, SRM 935, NIST Spec. Publ. 260-54, 1977. 

Phosphomolybdic acid-Potassium dichromate-Copper(II) sulfate. 

See Halogens or Interhalogens above Ammonium nitrate Metals Ammonium peroxodisulfate Iron Dinitrogen tetraoxide Metals Hydrogen peroxide Metals Nitryl fluoride Metals Peroxyformic acid Potassium dichromate Iron Potassium perchlorate Metal powders Sodium peroxide Metals... 

Potassium permanganate solution acidified with dilute sulfuric acid Potassium dichromate in with dilute sulfuric acid... 

Some chromium(VI) compounds, such as, chromium trioxide (chromic acid), potassium dichromate, potassium chromate, sodium dichromate, and sodium chromate, are very caustic and can cause bums upon dermal contact. These burns can facilitate the absorption of the compound and lead to systemic toxicity. 

The reaction of pyrazylmethylsodium with styrene oxide gives the secondary carbinol (26) in 73% yield and oxidation of compound 26 with acidic potassium dichromate yields the corresponding ketone.179 The sodio derivative reacts with butyl nitrite to give pyrazin-aldoxime (27) in 39% yield.180... 

Y. Madrid, J. Mesenguer, M. Bonilla, C. Camara, Lead hydride generation in lactic acid-potassium dichromate medium and its application to the determination of lead in fish, vegetables and drink samples, Anal. Chim. Acta, 237 (1990), 181-187. 

These thiophosphates are hydrolysed in dilute solution with evolution of H2S. They can be dissolved unchanged in alkalies. With salts of the heavy metals they give precipitates which are decomposed on warming, giving H2S. They are easily oxidised by nitric acid, potassium dichromate, etc. with deposition of sulphur. When treated... 

Cyanide. This should have been detected and confirmed in the preliminary test with dilute sulphuric acid (Prussian blue test or as Section IV.8, reaction 1). Sulphite. This anion will have been detected in the preliminary test with dilute sulphuric acid (potassium dichromate paper or fuchsin solution test). Hexacyanoferrate(II) (and Thiocyanate). Acidify 1 ml of the soda extract with dilute hydrochloric acid and add a few drops of iron(III) chloride solution. A deep-blue precipitate indicates hexacyanoferrate(II) present. Now add 0-5-1 ml iron(III) chloride solution, 0-2 g sodium chloride and half a Whatman filtration accelerator, shake the mixture vigorously and filter. A deep-red filtrate indicates thiocyanate present. 

Incompatible with CrO, (nitric + acetic acid), NOCl, nitryl perchlorate, permonosulfuric acid, NaOBr, (sulfuric acid + potassium dichromate), (thio-diglycol + hydrogen peroxide), trichloromelamine, air, HNO3, chloroform, and H2SO4. To fight fire, use CO2, dr chemical, alcohol foam. Used in production of drugs of abuse. 

Tetrabenzylarsonium chloride, (CeHs.CH2)4AsCl.— This may be isolated by heating benzyl chloride and tribenzylarsine under reflux for a long time, or in quantitative yield by heating the two substances in a sealed tube at 170° to 175° C. for three hours. The temperature should be kept below 180° C., or dibenzylarsine trichloride is formed. Tetrabenzylarsonium chloride forms triclinic crystals, M.pt. 160° C., readily soluble in hot water or alcohol. It is slowly decomposed by concentrated hydrochloric acid at high temperatures and imder pressure. The aqueous solution gives precipitates with nitric acid, potassium dichromate, potassium thiocyanate, potassium bromide, potassium iodide, picric add, and platinic chloride. 

Nickel peroxide. Oxoperoxobis(N-phenylbenzohydroxamato) molyb-denum(VI). Palladium(II) acetate-Tri-phenylphosphine. Palladium /-butyl peroxide trifluoroacetate. Periodic acid. Permonophosphoric acid. Potassium dichromate. Potassium hydrogen persulfate. Pyridinium dichromate. Ruthenium tetroxide. Selenium dioxide. Sodium hypochlorite. Titanium(IlI) chlo-ride-Hydrogen peroxide. Potassium nitrodisulfonate. Potassium peroxodi-sulfate. Pyridinium chlorochromate. Pyridinium chlorochromate-Hydrogen peroxide. Sodium permanganate monohydrate. Tetra-n-Butylammonium periodate. Thailium(III) acetate. Trimethyl-amine N-oxide. Triphenylmethylphos-phonium permanganate. 

TABLE 3-4 Recommended Absorbance Values for Acidic Potassium Dichromate Solutions... 

In 1873, it was first reported that cellulose that has been oxidized with chromic acid or potassium permanganate is weakened in alkaline solutions, and several years later these findings were confirmed. By 1899, it was known that cellulose that had been oxidized with nitric acid, or bromine in the presence of calcium carbonate, afforded oxidized celluloses from which D-glucoisosaccharinates were formed on suitable treatment with lime-water.Hydrocelluloses, alkaline-hypobromite oxycelluloses, and alkaline-hypochlorite oxycelluloses have no internal, alkali-sensitive links. Cellulose oxidized with neutral hypochlorite, acidic hypochlorite, potassium dichromate and sulfuric acid, potassium dichromate and oxalic acid, periodic acid, or metaperiodate gives products which are alkali-sensitive. Periodic acid oxycellulose and metaperiodate oxycellulose are much more alkali-sensitive than the others. ... 

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