Silver dichromate

Silver Chromate. Silver chromate, Ag2Cr04, is prepared by treating silver nitrate with a solution of chromate salt or by heating a suspension of silver dichromate [7784-02-3]. 

In neutral solution, the indicator is potassium chromate(VI). In acid solution the CrOj ion changes to Cr202 (p. 378), and since silver dichromate(VI) is soluble, chromate(VI) is not a suitable indicator other methods can be used under these conditions. (In alkaline solution, silverfl) oxide precipitates, so silver(I) nitrate cannot be used under these conditions.)... 

Several other polymer-bound oxidizing reagents have recently been reported in the literature (reaction 14). A polyethyleneimine-supported silver dichromate 35 has been shown to be a stable, mild, and efficient oxidizing agent for the conversion of alcohols to carbonyl compounds.51 A... 

Goudarzian, N. Ghahramani, P. Hossini, S. Polymeric Reagents. (1). Polyethyleneimine-Supported Silver Dichromate as a New Oxidzing Agent, Polym. Int. 1996, 39,61. 

Use of a protective colloid in solution prevents the formation of the ordinary and expected precipitate in many eases, and causes the formation of the expected substance -as colloidal sol. Silver nitrate (0.6 gram per liter and potassium dichromate (0.5 gram per liter) to one of which is added 0.1 volume of Itol gelatin solution (2 grains per 100 milliliters of water) are mixed with stirring silver dichromate sol is formed. 

Silver dichromate (Ag2Cr207), red precipitate by reaction of silver nitrate solution and potassium dichromate solution, changing to silver chromate upon boiling with H20. 

A reddish-brown precipitate of silver dichromate, Ag2Cr207, is formed with a concentrated solution of a dichromate this passes, on boiling with water, into the less soluble silver chromate. 

Bis(tetrabutylammonium) Dichromate 2.7.6J Tetrakis(pyrUline)silver Dichromate... 

Many chromium oxidants suffer from problems of stability, light sensitivity or acidity, but tetrakis(py-ridine)silver dichromate is stable, nonphotosensitive, nonhygroscopic and a neutral oxidant It can be used to oxidize allylic and benzylic alcohols selectively in benzene. Unfortunately, it cannot be used in chlorinated solvents because it decomposes in these solvents. 

Silver Dichromate, Ag2Cr207, is prepared by the addition of silver nitrate to a hot solution of potassium dichromate containing a large excess of nitric acid, and cooling till crystallisation occurs. The salt may readily be recrystallised from nitric acid, traces of which are, however, retained. It crystallises as red-black plates in the triclinic system, and has a density of 4-770. It cannot be dried without decomposition, for it is readily decomposed by water with formation of the neutral chromate and chromic acid. ... 

Silver dichromate-pyridine complex (tetrapyridine silver dichromate), Ag2Cr207 4C5H5N, an orange-yellow solid prepared by adding a warm solution of potassium dichromate to a solution of silver nitrate in water and pyridine, oxidizes allylic and benzylic alcohols to aldehydes and acyl-tiins to a-diketones [659]. 

Oxidations with a complex of pyridine with silver dichromate in benzene do not offer any advantages, and refluxing is necessary [659]. 

A mass of 0.017 g of silver dichromate (hg2Ct2 7) will dissolve in 300 mL of water at 25°C. Calculate the solubility product constant of silver dichromate. 

A silver dichromate complex with poly(ethyleneimine) has been used to oxidize benzyl alcohol in toluene to ben-zaldehyde in 98% yield.199 The polymeric reagent could be regenerated several times with no loss in activity. No... 

Bromine(III) fluoride fluorinates everything which dissolves in it. Numerous oxides, halides and salts of oxyacids are converted into fluorides. Carbonates, nitrates and iodates are usually completely converted into the fluorides, while some of the metal oxides, such as BeO, MgO, ZnO or AI2O3 are only partly fluorinated by liquid bromine(III) fluoride. Sodium vanadate yields a mixture of tetrafluorooxovanadate and hexafluorovanadate i, potassium or silver dichromates give KCrOF4 and AgCrOF4 resp. i. Potassium permanganate is converted into KMnFs, potassium metaphosphate into potassium hexafluoro-phosphate and sodium borate into the tetrafluoroborate ... 

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