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ferrocyanide

ferrocyanide

ferrocyanide Sentence Examples

  • They are soluble in water and give characteristic precipitates with platinic and auric chlorides, and with potassium ferrocyanide.

  • Of the principal workers in this field we may notice Friedrich Hoffmann, Andreas Sigismund Marggraf (who detected iron by its reaction with potassium ferrocyanide, and potassium and sodium by their flame colorations), and especially Carl Scheele and Torbern Olof Bergman.

  • It may also be prepared by heating formic and oxalic acids (or their salts) with concentrated sulphuric acid (in the case of oxalic acid, an equal volume of carbon dioxide is produced); and by heating potassium ferrocyanide with a large excess of concentrated sulphuric acid, K 4 Fe(CN) 6 -i-6H2S04+6H20=2K2S04+FeS04+3(NH4)2S04+6C0.

  • Quinone-dioxime, HON: C 6 H 4: NOH, crystallizes in colourless or yellow needles, which decompose when heated to about 240° C. Potassium ferrocyanide in alkaline solution oxidizes it to dinitrosobenzene, whilst cold concentrated nitric acid oxidizes it to para-dinitrobenzene.

  • Mercuric cyanide, Hg(NC)2, is a sparingly soluble salt formed by dissolving precipitated mercuric oxide in hydrocyanic acid, or by boiling potassium ferrocyanide with mercuric sulphate and water: 2K4Fe(NC)6+3HgS04=3Hg(NC)2+ 3K 2 SO 4 -{-K 2 Fe[Fe(NC) 6 ].

  • Potassium cyanide may be obtained by fusing potassium ferrocyanide either alone - K4Fe(NC)6=4KNC+ FeC2+N2 - or with potassium carbonate [V.

  • Rossler and Hasslacher prepare the double potassium sodium cyanide by fusing potassium ferrocyanide with sodium, the product of fusion being extracted with water and the solution evaporated: K 4 Fe(NC) 6 +2Na = Fe+ 4KNC 2NaNC. This process gives a product free from cyanate, which was always formed in the older fusion processes.

  • Potassium ferrocyanide, K 4 Fe(NC) 6, (yellow prussiate of potash), was first obtained by decomposing Prussian blue with caustic potash: Fe4[Fe(NC)6]3 + 12KHO = 3K 4 Fe(NC) 6 +4Fe(OH) 3; it may be also obtained by warming a solution of ferrous sulphate with an excess of potassium cyanide: FeS04-I-6KNC = K4Fe(NC)6+ K2S04.

  • 9474 (1892)] passes the gas (after freeing it from ammonia) through a solution of potassium carbonate containing ferric oxide or ferrous carbonate (actually ferrous sulphate and potassium carbonate) in suspension; the sulphuretted hydrogen in the gas probably converts the iron salts into ferrous sulphide which then, in the presence of the hydrocyanic acid in the gas, and the alkaline carbonate, forms the ferrocyanide, thus: FeS+6HCN+ 2K 2 CO 3 = K 4 Fe(NC) 6 + H 2 S + 2CO 2 + 2H 2 0.

  • The soluble salts are removed by lixiviation, and the residue is boiled with lime to form the soluble calcium ferrocyanide, which is finally converted into the potassium salt by potassium chloride or carbonate.

  • Potassium ferrocyanide may be estimated quantitatively in acid solution by oxidation to ferricyanide by potassium permanganate (in absence of other reducing agents): 5K 4 Fe(NC)s + KMnO 4 + 4H2S04= 5K 3 Fe(NC)s + 3K2S04+MnS04+4H20.

  • On the small scale it may be prepared by adding an acid solution of a ferrous salt to a solution of potassium ferrocyanide.

  • Soluble Prussian blue, K2Fe2[Fe(NC)6]2, potassium ferric ferrocyanide, is formed when a solution of potassium ferrocyanide is added to an insufficiency of a solution of a ferric salt (t), or when potassium ferricyanide is added to a ferrous salt (2): (t) 2K 4 Fe(NC) 6 + 2FeC1 3 = 6KC1 + K2Fe2[Fe(NC)6]2 (2) 2K 3 Fe(NC)s + 2FeC1 2 = 4KC1 -{- K2Fe2[Fe(NC)s]z.

  • Potassium ferricyanide, K 3 Fe(NC)s, red prussiate of potash, is obtained by oxidizing potassium ferrocyanide with chlorine, bromine, &c., 2K 4 Fe(NC) 6 + C1 2 = 2K 3 Fe(NC) 6 + 2KC1.

  • Zeit., 1889, 13, p. 1701; 17, p. 1712) adds calcium plumbate to a solution of potassium ferrocyanide and passes carbon dioxide through the mixture: 2K 4 Fe(NC) -f-Ca 2 PbO 4 -} 4C02= K3Fe(NC)6+ K2C03+PbC03+2CaC03.

  • The zinc sulphate is added in order to remove the ferrocyanide formed as an insoluble zinc salt: 2K 3 Fe(NC)6+2KI=2K 4 Fe(NC) 6 -0 2.

  • It is prepared by oxidizing potassium ferrocyanide with a diluted nitric acid.

  • - Considerable discussion has taken place as to the structure of the metallic cyanides, since potassium cyanide and silver cyanide react with alkyl iodides to form nitriles and isonitriles respectively, thus apparently pointing to the fact that these two compounds possess the formulae KCN and AgNC. The metallic cyanides are analogous to the alkyl isocyanides, since they form soluble double silver salts, and the fact that ethyl ferrocyanide on distillation yields ethyl isocyanide also points to their isocyanide structure.

  • He mentioned as an important exception the case of ferric ferrocyanide, which, when dissolved in oxalic acid, transmits the rays in great abundance, though the same rays be absorbed both by ferrocyanides and by ferric salts.

  • It may also be prepared by heating a mixture of carbon, oxide of iron and magnesite to bright redness; and by heating a mixture of magnesium ferrocyanide and sodium carbonate, the double cyanide formed being then decomposed by heating it with metallic zinc. Electrolytic methods have entirely superseded the older methods.

  • It was found, for instance, that a film of insoluble copper ferrocyanide, deposited in the walls of a porous vessel by the inward diffusion and meeting of solutions of copper sulphate and potassium ferrocyanide, would allow water to pass, but retained sugar dissolved in that liquid.

  • Experiments with membranes of copper ferrocyanide have verified this result for solutions of cane-sugar of moderate dilutions.

  • Although even good membranes of copper ferrocyanide are rarely perfectly semi-permeable, and in other membranes such as indiarubber, &c., which have been used, the defects from the theoretical values of the equilibrium pressure are very great, yet, in the light of the exact verification of theory given by the experiments described above, it is evident that such failures to reach the limiting value in no wise invalidate the theory of osmotic equilibrium.

  • The osmotic pressures of strong sugar solutions were measured successfully by a direct method with semi-permeable membranes of copper ferrocyanide by Lord Berkeley and E.

  • Potassium ferrocyanide gives a precipitate even in very dilute solution.

  • P. Pfeffer (Osmotische Untersuchungen, Leipzig, 1877) was the first to obtain satisfactory measurements of osmotic pressures of cane-sugar solutions up to nearly I atmosphere by means of semi-permeable membranes of copper ferrocyanide.

  • Ammonia gives a characteristic blue coloration when added to a solution of a copper salt; potassium ferrocyanide gives a brown precipitate, and, if the solution be very dilute, a brown colour is produced.

  • The most modern and the most generally accepted method is volumetric, and is based on the reaction between zinc chloride and potassium ferrocyanide, by which insoluble zinc ferrocyanide and soluble potassium chloride are formed; the presence of the slightest excess of potassium ferrocyanide is shown by a brownish tint being imparted by the solution to a drop of uranium nitrate.

  • The ferrocyanide solution is standardized by dissolving i gramme of pure zinc in 6 cc. of hydrochloric acid, adding ammonium chloride, and titrating as before.

  • Potassium selenocyanide, KSeCN, is obtained by the action of selenium on a concentrated aqueous solution of potassium cyanide, or by heating selenium with anhydrous potassium ferrocyanide (W.

  • Ferrous salts also give a bluish white precipitate with ferrocyanide, which on exposure turns to a dark blue; ferric salts are characterized by the intense purple coloration with a thiocyanate.

  • potassium ferrocyanide and zinc acetate were added to each sample, which was then cleaned up on a disposable cartridge.

  • They are soluble in water and give characteristic precipitates with platinic and auric chlorides, and with potassium ferrocyanide.

  • They give a characteristic pale red precipitate with sodium pyrophosphate, soluble in an excess of the precipitant; they also form precipitates on the addition of platinic chloride and potassium ferrocyanide.

  • Of the principal workers in this field we may notice Friedrich Hoffmann, Andreas Sigismund Marggraf (who detected iron by its reaction with potassium ferrocyanide, and potassium and sodium by their flame colorations), and especially Carl Scheele and Torbern Olof Bergman.

  • In the case of copper, the colour reactions with potassium ferrocyanide or ammonia are usually employed; traces of ammonia are estimated with Nessler's reagent; sulphur in iron and steel is determined by the tint assumed by a silver-copper plate suspended in the gases liberated when the metal is dissolved in sulphuric acid (Eggertz's test) (see W.

  • It may also be prepared by heating formic and oxalic acids (or their salts) with concentrated sulphuric acid (in the case of oxalic acid, an equal volume of carbon dioxide is produced); and by heating potassium ferrocyanide with a large excess of concentrated sulphuric acid, K 4 Fe(CN) 6 -i-6H2S04+6H20=2K2S04+FeS04+3(NH4)2S04+6C0.

  • Quinone-dioxime, HON: C 6 H 4: NOH, crystallizes in colourless or yellow needles, which decompose when heated to about 240° C. Potassium ferrocyanide in alkaline solution oxidizes it to dinitrosobenzene, whilst cold concentrated nitric acid oxidizes it to para-dinitrobenzene.

  • phys., 18 79 (5), 18, p. 380); by passing induction sparks through a mixture of acetylene and nitrogen; by the dry distillation of ammonium formate; by the decomposition of the simple cyanides with mineral acids; and by distilling potassium ferrocyanide with dilute sulphuric acid (F.

  • Mercuric cyanide, Hg(NC)2, is a sparingly soluble salt formed by dissolving precipitated mercuric oxide in hydrocyanic acid, or by boiling potassium ferrocyanide with mercuric sulphate and water: 2K4Fe(NC)6+3HgS04=3Hg(NC)2+ 3K 2 SO 4 -{-K 2 Fe[Fe(NC) 6 ].

  • Potassium cyanide may be obtained by fusing potassium ferrocyanide either alone - K4Fe(NC)6=4KNC+ FeC2+N2 - or with potassium carbonate [V.

  • Alder, English patent 1 353 (1900)]; in the latter case the chief reaction probably is: K 4 Fe(NC) 6 + K 2 CO 3 =4KNC, ',+ 2KOCN + CO + Fe more potassium ferrocyanide is occasionally added in small quantities, in order to decompose the cyanate formed; 2KOCN+2K4Fe(NC)6= ioKNC + 2FeO + 4C + 2N2; 2Fe0A+ 2C = 2C0 + 2Fe.

  • Rossler and Hasslacher prepare the double potassium sodium cyanide by fusing potassium ferrocyanide with sodium, the product of fusion being extracted with water and the solution evaporated: K 4 Fe(NC) 6 +2Na = Fe+ 4KNC 2NaNC. This process gives a product free from cyanate, which was always formed in the older fusion processes.

  • Potassium ferrocyanide, K 4 Fe(NC) 6, (yellow prussiate of potash), was first obtained by decomposing Prussian blue with caustic potash: Fe4[Fe(NC)6]3 + 12KHO = 3K 4 Fe(NC) 6 +4Fe(OH) 3; it may be also obtained by warming a solution of ferrous sulphate with an excess of potassium cyanide: FeS04-I-6KNC = K4Fe(NC)6+ K2S04.

  • 9474 (1892)] passes the gas (after freeing it from ammonia) through a solution of potassium carbonate containing ferric oxide or ferrous carbonate (actually ferrous sulphate and potassium carbonate) in suspension; the sulphuretted hydrogen in the gas probably converts the iron salts into ferrous sulphide which then, in the presence of the hydrocyanic acid in the gas, and the alkaline carbonate, forms the ferrocyanide, thus: FeS+6HCN+ 2K 2 CO 3 = K 4 Fe(NC) 6 + H 2 S + 2CO 2 + 2H 2 0.

  • The soluble salts are removed by lixiviation, and the residue is boiled with lime to form the soluble calcium ferrocyanide, which is finally converted into the potassium salt by potassium chloride or carbonate.

  • Potassium ferrocyanide may be estimated quantitatively in acid solution by oxidation to ferricyanide by potassium permanganate (in absence of other reducing agents): 5K 4 Fe(NC)s + KMnO 4 + 4H2S04= 5K 3 Fe(NC)s + 3K2S04+MnS04+4H20.

  • Prussian blue, Fe 7 (NC) 18 or Fe4[Fe(NC)6]3, ferric ferrocyanide, was discovered in 1710 by a German manufacturer named Diesbach, who obtained it by the action of fused alkali and iron salts on nitrogenous organic matter (e.g.

  • It is now prepared from the calcium ferrocyanide formed in gas purifiers (see above) by decomposition with ferrous' sulphate.

  • On the small scale it may be prepared by adding an acid solution of a ferrous salt to a solution of potassium ferrocyanide.

  • Soluble Prussian blue, K2Fe2[Fe(NC)6]2, potassium ferric ferrocyanide, is formed when a solution of potassium ferrocyanide is added to an insufficiency of a solution of a ferric salt (t), or when potassium ferricyanide is added to a ferrous salt (2): (t) 2K 4 Fe(NC) 6 + 2FeC1 3 = 6KC1 + K2Fe2[Fe(NC)6]2 (2) 2K 3 Fe(NC)s + 2FeC1 2 = 4KC1 -{- K2Fe2[Fe(NC)s]z.

  • Potassium ferricyanide, K 3 Fe(NC)s, red prussiate of potash, is obtained by oxidizing potassium ferrocyanide with chlorine, bromine, &c., 2K 4 Fe(NC) 6 + C1 2 = 2K 3 Fe(NC) 6 + 2KC1.

  • Zeit., 1889, 13, p. 1701; 17, p. 1712) adds calcium plumbate to a solution of potassium ferrocyanide and passes carbon dioxide through the mixture: 2K 4 Fe(NC) -f-Ca 2 PbO 4 -} 4C02= K3Fe(NC)6+ K2C03+PbC03+2CaC03.

  • The zinc sulphate is added in order to remove the ferrocyanide formed as an insoluble zinc salt: 2K 3 Fe(NC)6+2KI=2K 4 Fe(NC) 6 -0 2.

  • It is prepared by oxidizing potassium ferrocyanide with a diluted nitric acid.

  • - Considerable discussion has taken place as to the structure of the metallic cyanides, since potassium cyanide and silver cyanide react with alkyl iodides to form nitriles and isonitriles respectively, thus apparently pointing to the fact that these two compounds possess the formulae KCN and AgNC. The metallic cyanides are analogous to the alkyl isocyanides, since they form soluble double silver salts, and the fact that ethyl ferrocyanide on distillation yields ethyl isocyanide also points to their isocyanide structure.

  • He mentioned as an important exception the case of ferric ferrocyanide, which, when dissolved in oxalic acid, transmits the rays in great abundance, though the same rays be absorbed both by ferrocyanides and by ferric salts.

  • It may also be prepared by heating a mixture of carbon, oxide of iron and magnesite to bright redness; and by heating a mixture of magnesium ferrocyanide and sodium carbonate, the double cyanide formed being then decomposed by heating it with metallic zinc. Electrolytic methods have entirely superseded the older methods.

  • It was found, for instance, that a film of insoluble copper ferrocyanide, deposited in the walls of a porous vessel by the inward diffusion and meeting of solutions of copper sulphate and potassium ferrocyanide, would allow water to pass, but retained sugar dissolved in that liquid.

  • Experiments with membranes of copper ferrocyanide have verified this result for solutions of cane-sugar of moderate dilutions.

  • Although even good membranes of copper ferrocyanide are rarely perfectly semi-permeable, and in other membranes such as indiarubber, &c., which have been used, the defects from the theoretical values of the equilibrium pressure are very great, yet, in the light of the exact verification of theory given by the experiments described above, it is evident that such failures to reach the limiting value in no wise invalidate the theory of osmotic equilibrium.

  • The osmotic pressures of strong sugar solutions were measured successfully by a direct method with semi-permeable membranes of copper ferrocyanide by Lord Berkeley and E.

  • Wdhler oxidized potassium ferrocyanide to potassium cyanate by fusing it with lead or manganese dioxide, converted this cyanate into ammonium cyanate by adding ammonium sulphate, and this on evaporation gives urea, thus: K 4 Fe(NC)r-->K CNO--->NH4CNO->CO (NH2)2 It may also be prepared by the action of ammonia on carbonyl chloride, diethyl carbonate, chlorcarbonic ester or urethane; by heating ammonium carbamate in a sealed tube to 130-140° C.; by oxidizing potassium cyanide in acid solution with potassium permanganate (E.

  • Potassium ferrocyanide gives a precipitate even in very dilute solution.

  • P. Pfeffer (Osmotische Untersuchungen, Leipzig, 1877) was the first to obtain satisfactory measurements of osmotic pressures of cane-sugar solutions up to nearly I atmosphere by means of semi-permeable membranes of copper ferrocyanide.

  • Ammonia gives a characteristic blue coloration when added to a solution of a copper salt; potassium ferrocyanide gives a brown precipitate, and, if the solution be very dilute, a brown colour is produced.

  • The most modern and the most generally accepted method is volumetric, and is based on the reaction between zinc chloride and potassium ferrocyanide, by which insoluble zinc ferrocyanide and soluble potassium chloride are formed; the presence of the slightest excess of potassium ferrocyanide is shown by a brownish tint being imparted by the solution to a drop of uranium nitrate.

  • The ferrocyanide solution is standardized by dissolving i gramme of pure zinc in 6 cc. of hydrochloric acid, adding ammonium chloride, and titrating as before.

  • Potassium selenocyanide, KSeCN, is obtained by the action of selenium on a concentrated aqueous solution of potassium cyanide, or by heating selenium with anhydrous potassium ferrocyanide (W.

  • Ferrous salts also give a bluish white precipitate with ferrocyanide, which on exposure turns to a dark blue; ferric salts are characterized by the intense purple coloration with a thiocyanate.

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