Potassium acetate arsenate

Redox titrants (mainly in acetic acid) are bromine, iodine monochloride, chlorine dioxide, iodine (for Karl Fischer reagent based on a methanolic solution of iodine and S02 with pyridine, and the alternatives, methyl-Cellosolve instead of methanol, or sodium acetate instead of pyridine (see pp. 204-205), and other oxidants, mostly compounds of metals of high valency such as potassium permanganate, chromic acid, lead(IV) or mercury(II) acetate or cerium(IV) salts reductants include sodium dithionate, pyrocatechol and oxalic acid, and compounds of metals at low valency such as iron(II) perchlorate, tin(II) chloride, vanadyl acetate, arsenic(IV) or titanium(III) chloride and chromium(II) chloride. 

A powerful oxidizer. Explosive reaction with acetaldehyde, acetic acid + heat, acetic anhydride + heat, benzaldehyde, benzene, benzylthylaniUne, butyraldehyde, 1,3-dimethylhexahydropyrimidone, diethyl ether, ethylacetate, isopropylacetate, methyl dioxane, pelargonic acid, pentyl acetate, phosphoms + heat, propionaldehyde, and other organic materials or solvents. Forms a friction- and heat-sensitive explosive mixture with potassium hexacyanoferrate. Ignites on contact with alcohols, acetic anhydride + tetrahydronaphthalene, acetone, butanol, chromium(II) sulfide, cyclohexanol, dimethyl formamide, ethanol, ethylene glycol, methanol, 2-propanol, pyridine. Violent reaction with acetic anhydride + 3-methylphenol (above 75°C), acetylene, bromine pentafluoride, glycerol, hexamethylphosphoramide, peroxyformic acid, selenium, sodium amide. Incandescent reaction with alkali metals (e.g., sodium, potassium), ammonia, arsenic, butyric acid (above 100°C), chlorine trifluoride, hydrogen sulfide + heat, sodium + heat, and sulfur. Incompatible with N,N-dimethylformamide. 

DCA labelled with As has been obtained from [ As]arsenic trioxide and potassium acetate at 355 °C for 4 h under inert gas and subsequent trapping of the dimethylarsine oxide produced in a ferric chloride solution (50% hydrated FeClj in cone. HCl) (equation 53). 

The first organometal to be reported was cacodyl [tetramethyldiarsine, (CH3)4As2]. It was prepared almost as an afterthought by Cadet de Gassicourt, a Parisian military apothecary, in 1760 (45). Cadet was working on cobalt solutions for use as invisible inks. The two common ores of cobalt, smaltite and cobaltite, both contain arsenic, and arsenic trioxide was formed as a by-product. When he pyrolyzed this oxide with potassium acetate. Cadet got a red-brown liquid that fumed in air and gave off a terrible stench. 

Derivation By distilling a mixture of arsenic trioxide and potassium acetate, and oxidizing the resulting product with mercuric oxide. 

Solid Compounds. The tripositive actinide ions resemble tripositive lanthanide ions in their precipitation reactions (13,14,17,20,22). Tetrapositive actinide ions are similar in this respect to Ce . Thus the duorides and oxalates are insoluble in acid solution, and the nitrates, sulfates, perchlorates, and sulfides are all soluble. The tetrapositive actinide ions form insoluble iodates and various substituted arsenates even in rather strongly acid solution. The MO2 actinide ions can be precipitated as the potassium salt from strong carbonate solutions. In solutions containing a high concentration of sodium and acetate ions, the actinide ions form the insoluble crystalline salt NaM02(02CCH2)3. The hydroxides of all four ionic types are insoluble ... 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

Dermal Effects. Skin irritation was noted in wildlife officers at the RMA after they handled sick or dead ducks without gloves (NIOSH 1981). Although the investigators concluded that diisopropyl methylphosphonate contributed to the local effects, a number of other compounds were present. Analysis of the pond water indicated the presence of a number of organic and inorganic contaminants, including diisopropyl methylphosphonate (11.3 ppm) aldrin (0.368 ppm) dieldrin (0.0744 ppm) dicyclo-pentadiene, bicycloheptadiene, diethyl benzene, dimethyl disulfide, methyl acetate, methyl isobutyl ketone, toluene, and sodium (49,500 ppm) chloride (52,000 ppm) arsenic (1,470 ppm) potassium (180 ppm) fluoride (63 ppm) copper (2.4 ppm) and chromium (0.27 ppm). Because of the presence of numerous compounds, it is unclear whether diisopropyl methylphosphonate was related to the irritation. 

The evidence for the formation of complex heteropoly-acids with tantalic acid is very comparable to that set forth in the case of niobic acid (see p. 165). Solutions of tantalates are readily hydrolysed in aqueous solution by boiling, and even more readily by the addition of mineral acids, acetic acid or succinic acid in the presence, however, of arsenious add, arsenic add, tartaric add or dtric add no precipitation of tantalic add takes place. Again, tincture of galls yields a yellow predpitate with solutions of tantalates which have been rendered feebly acid with sulphuric add this reaction does not, however, take place in the presence of ordinary tartaric add, racemic add or citric acid. Tartaric add also prevents the formation of the predpitates which are thrown down on the addition of potassium ferrocyanide or potassium ferricyanide to faintly acid solutions of tantalates, and hinders the precipitation of tantalic add from solutions in inorganic acids by the action of ammonia. In all these cases it is assumed that complex acids or their salts are produced, in consequence of which the usual reaction does not take place. 

AgNOs + 4As = 3Ag + 2 As 203 + 3NO If the arsenic is added as a piece the silver is deposited in the form of a dull, white, smooth plating. The reaction does not go to completion even after several months contact. On the other hand, silver is completely displaced within a few hours from solutions saturated with silver nitrite or sulphate, and after a longer time from saturated aqueous solutions of silver acetate and tartrate. In each case arsenic goes into solution as the trioxide. With a solution of silver cyanide in aqueous potassium cyanide the reaction takes a different course, probably following the equation ... 

The bromide may also be prepared (1) by adding arsenic powder to a mixture of carbon disulphide and bromine (2 1 by weight) and agitating the liquid until decolorised 3 on evaporation, crystals of the bromide remain (2) by heating a mixture of arsenious oxide, potassium bromide and acetic acid at 100° C. 4 (3) by heating a mixture of arsenious oxide and sulphur in a current of bromine vapour.5... 

Many other methods of preparation have been employed. For example, the triiodide is formed when arsenious oxide,5 or a mixture of this oxide with sulphur,6 is heated in iodine vapour or when arsenious oxide is heated with iodine,7 hydriodic acid,8 a mixture of potassium iodide and acetic acid,9 or a mixture of potassium iodide and potassium hydrogen sulphate.10 When arsenic disulphide and iodine, in the proportions 1 As Ss 3la, are heated together, arsenic triiodide is formed.11 When arsenic trisulphide is fused with an excess of iodine, the product is soluble in carbon disulphide and the solution on evaporation deposits arsenic triiodide, then a sulphiodide and finally sulphur with excess of sulphide the product is the sulphiodide, AsS2I. If a solution of iodine in carbon disulphide is added to arsenic di- or tri-sulphide, the triiodide and sulphur are formed. The triiodide is also produced when a mixture of the trisulphide and mercuric iodide is heated 12. when hydriodic... 

Barium Metarsenite, Ba(As02)3, may be obtained by warming barium chloride with a solution of ammonium arsenite to which acetic acid has been added until arsenious acid is on the point of precipitation. The precipitate is then dried at 100° C.2 It is a white powder, easily soluble in water, but it can also be obtained as a gelatinous mass 3 when a mixture of barium chloride and potassium metarsenite in solution is left to stand for a few hours. On strongly heating it decomposes to form arsenate and free arsenic, but to a much less extent than is the case with the orthoarsenite.4... 

Lead Orthoarsenite, Pb3(As03)2, is obtained as a white precipitate on adding a solution of basic lead acetate to a boiling aqueous solution of arsenious oxide,9 or of potassium tetrarsenite,10 or by the action of an alkali plumbite on an alkali arsenite.11 When dried in a dark air oven the arsenite remains white, but when exposed to light some specimens turn brown, a change which has been attributed to reduction of the lead to suboxide,12 but some arsenate and free arsenic are formed. All specimens... 

Colloidal cobalt arsenate has been obtained in the form of an opalescent jelly either by mixing in the cold a solution of a cobalt salt of a strong acid with potassium dihydrogen orthoarsenate,8 or by successively treating an aqueous solution of a cobaltous salt with ammonium sulphate, acetic acid and an excess of sodium orthoarsenate.9... 

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