Potassium pyrosulfate

Ammonium fluorosulfate is produced from ammonium fluoride by reaction with sulfur trioxide, oleum, or potassium pyrosulfate, 1 2820 (48). Solutions of ammonium fluorosulfate show Htfle evidence of hydrolysis and the salt may be recrystallized from hot water. Ammonium fluorosulfate absorbs anhydrous ammonia to form a series of Hquid amines that contain 2.5—6 moles of ammonia per mole of salt (77). 

Tantalum Oxides. Tantalum pentoxide [1314-61 -0] Ta20, (mp = 1880°C, density = 8.73 g/cm ) is a white powder existing in two thermodynamically stable modifications. The orthorombic P-phase changes at 1360°C into the tetragonal a-modiftcation. The existence of an S-modiftcation has also been reported (70). Tantalum pentoxide reacts slowly with hot hydrofluoric acid but is insoluble in water and in most solutions of acids and alkalies. For analytical purposes, it can be dissolved by fusion with alkali hydroxides, alkali carbonates, and potassium pyrosulfate. 

The analytical chemistry of titanium has been reviewed (179—181). Titanium ores can be dissolved by fusion with potassium pyrosulfate, followed by dissolution of the cooled melt in dilute sulfuric acid. For some ores, even if all of the titanium is dissolved, a small amount of residue may still remain. If a hiU analysis is required, the residue may be treated by moistening with sulfuric and hydrofluoric acids and evaporating, to remove siUca, and then fused in a sodium carbonate—borate mixture. Alternatively, fusion in sodium carbonate—borate mixture can be used for ores and a boiling mixture of concentrated sulfuric acid and ammonium sulfate for titanium dioxide pigments. For trace-element deterrninations, the preferred method is dissolution in a mixture of hydrofluoric and hydrochloric acids. 

For this reason a lower melting electrolyte was sought, one which would melt below 350 °C. Potassium pyrosulfate, K2S207, was a natural choice though thermally unstable above 300 °C in the absence of S03,... 

Table 3. Comparison of experimental and calculated equilibrium potentials for various gas environments and electrolyte compositions, 400 °C, relative to Ag/Ag+ reference. Results are reported on the basis of changes in the equilibrium potential relative to a base case of pure potassium pyrosulfate under an air environment.

For dissolving particularly difficult metal oxides, the acidic flux potassium pyrosulfate (K2S207) may be used. 

Depending on the material of the crucible, various cleaning agents may be used. Whenever possible, water and mild abrasives like sand are preferred. Cleaning with acids is usually applicable to platinum crucibles, but should be avoided in the case of alumina crucibles. Platinum crucibles can be cleaned especially thoroughly in a melt of potassium pyrosulfate. In all such operations it is important for the crucibles... 

The 5-nitrosopyrrolopyrimidine (46) is converted by potassium pyrosulfate or triphenylphosphine into the pyrimidinopyrimidine (47). The reaction is thought to go via a nitrene, captured by intramolecular insertion. Nucleophilic attack by ammonia or primary amines at C-6 leads to the same ring enlargement, probably by the mechanism indicated. Treatment of the product (48 R = H)] with nitrous acid produces a compound (47) identical with that from the pyrosulfate reaction (Scheme 15) (72CPB2076). 

Sulfates. Potassium sulfate. [CAS 7778-80-5], sulfate of potash, K2.SO4, white solid, soluble. Common constituent of potassium salt minerals. Used (l)as an important potassium fertilizer, (2) in the preparation of potassium or potash alums potassium hydrogen sulfate, KHSO4, white solid, soluble potassium pyrosulfate. K2S2O7, white solid, soluble, formed by heating potassium hydrogen sulfate to complete loss ot H2O. See also Fertilizer. 

The only satisfactory method of preparing benzalaniline is the action of aniline on benzaldehyde.1 The use of potassium pyrosulfate as a dehydrating agent, as suggested by Odell and Hines,2 does not seem necessary. 

Morphin was extracted from the plant vegetable (the poppy) by the mixture of water and methanol or the aqueous solution of potassium pyrosulfate. The precipitation of the morphin was carried out by addition to the extract the aqueous solution of sodium carbonate. 

B. Fuse about 1 mg of sample with about 50 mg of potassium pyrosulfate in a porcelain crucible, cool, and break up the mass with a glass rod. Add 3 mL of water, and dissolve by boiling. Add 1 drop of phenolphthalein TS, mix, and then add drops of a 1 10 solution of sodium hydroxide until just pink. Add 500 mg of sodium acetate, 0.5 mL of 1 N acetic acid, and 0.5 mL of a 1 500 solution of nitroso R salt. A red or orange-red color appears at once. Add 0.5 mL of hydrochloric acid, and boil for 1 min. The red color persists. 

Potassium pyrosulfate, K2S2O7, is formed by heating potassium hydrogen sulfate at moderate temperatures. Metallic oxides, such as ferrio oxide, can be dissolved in the medten potassium pyrosulfate. Write the equations for the reaction involved. 

Potassium Permanganate 7779-25-1 Magnesium Citrate 7790-62-7 Potassium Pyrosulfate... 

Potassium pyrosulfate is a potent acidic flux that is particularly useful for attacking the more intractable metal oxides. Fusions with this reagent are performed at about 400°C at this temperature, the slow evolution of the highly acidic sulfur trioxide takes place ... 

Potassium pyrosulfate can be prepared by heating potassium hydrogen sulfate 2KHSO4 - K2S2O7 -H H2O... 

Extrapolation techniques both for the grain size and specific surface area require a relative large number of samples (10-15). Further complicating is the fact that the calculation of the regression line is a tedious and mostly inaccurate procedure. The quartz-correction method involves fusion with potassium pyrosulfates which preferentially removes the layered silicates (clay), organic and inorganic carbon and sul fides with a residue made up of quartz plus feldspar and resistant heavy minerals such as zircone (Thomas et al., 1976). 

For further elucidation of the mechanism of the overall reaction (V.57), one must determine the abundance of ionic species of tetravalent and pentavalent vanadium in a potassium pyrosulfate melt. Present data for the equilibrium of reaction (V.63) due to Mars and Maessen 53) are consistent with the assumption that tetravalent vanadium is present in form of VOi ions, whereas pentavalent vanadium is present in form of VOa and V0 + ions in comparable amounts 54). The concentrations of these ions are interrelated by the equilibrium of the reactions... 

The literature data show that many mediods were used for oxoacidity studies and estimation of the acidic properties of melts. One simplest mefliod involves indicator. Acid-base indicators usually employed in aqueous solutions for protic aeidity measurements have been used for acidity studies in molten KNOj-LiNOj at 210 C and KSCN at 200"C. The color of indicator solution, relative to acidity, changes during titration of bases (sodium hydroxide or peroxide) by potassium pyrosulfate, KjSjOy ... 

A kinetic method was used for Lux acidity studies in molten nitrates. The interaction between the nitrate melts KNOs-NaNOs and potassium pyrosulfate was studied. ... 

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