Ammonium Acetate Sulphide Solution

Chemical deposition of both M0S2 and MoSei has been reported from ammonium molybdate solution [76,77], For the sulphur and selenium sources, thioacetamide and selenosulphate were used, respectively. Ammonium hydroxide was added to the sulphide solution, while an acetic acid/ammonium acetate buffer was used with the selenide solution (pH values were not given). Reducing agents (either hydrazine [76] or sodium dithionite [77]) were added to the baths. Deposition was started at 90-100°C, followed by lowering to room temperature. 

Mercuric thiocyanate, which is formed as a white precipitate when mercuric nitrate and potassium thiocyanate solutions are mixed, is soluble in excess of either solution. When dried, this salt is inflammable, forming a voluminous ash known as Pharaoh s serpents. By the interaction of a mercuric salt with ammonium thiocyanate and thio-carbamide in acetic acid solution in the presence of an oxidising agent, or by the action of hydrogen sulphide on mercuric thiocyanate, the phototropic compound HS.Hg.CNS is obtained.6... 

Heavy Metals and Earths. — The solution of 5 gm. of ammonium acetate in 100 cc. of water should not lie affected by hydrogen sulphide water. Furthermore, the addition of ammonia water and ammonium oxalate solution should cause neither a coloration nor a turbidity. 

Heavy Metals. —To a solution of 5 gm. of ammonium carbonate in 30 cc. of water is added 30 cc. of dilute acetic acid, then 20 cc. of ammonia water, then a few drops of ammonium sulphide solution. No precipitate should form, nor should the liquid acquire a green or a brown color. 

Lime, Alumina, and Heavy Metals. Dissolve 5 gm. of potassium bicarlxnmtc in 25 cc.. of water and 15 cc. of diluted acetic acid. Add 5 cc. of ammonia water and lieul for half an hour on the water-bath. No IlncUs should separate, m>r should any precipitate form. Furthermore, on adding to the slightly alkaline solution some nmniunhun oxidate sola tion and ammonium sulphide solution, no ehuiige six add appear. 

Alumina, Calcium, and Heavy Metals. — 2.5 gm. of potassium hydroxide should completely dissolve in 10 cc. of water yielding a clear and colorless solution. Dilute the solution to 100 cc. and add 15 cc. of acetic acid (sp. gr. 1.041), followed by 10 cc. of ammonia water a slight turbidity may form within five minutes, but no flocculent precipitate of aluminum hydroxide should develop. The solution so tested, filtered if necessary, should not exhibit an immediate turbidity on adding ammonium oxalate solution and on the addition of ammonium sulphide solution should acquire at most a slight green color. 

It is rarely necessary to determine quantitatively the separate components of the residue. When the lead sulphate is to be determined, the residue is extracted with ammonium acetate solution in the hot, the liquid filtered and the filtrate precipitated with hydrogen sulphide the lead sulphide is dissolved in nitric acid, and the procedure indicated in the next section (6) followed. 

The residue insoluble in water or a new portion of the substance is treated with dilute acetic acid, in which the zinc oxide should dissolve easily without evolution of gas. Effervescence indicates carbonates (white lead, chalk) if hydrogen sulphide is evolved, zinc sulphide (lithopone) may be present. Any residue insoluble in acetic acid may contain lead, barium or calcium sulphate or day, these being recognised as in white lead (q.v., paragraph i). Lastly, the acetic acid solution, when treated with caustic soda, should give a white precipitate quite soluble in excess of alkali and the alkaline solution should give a white precipitate with ammonium sulphide. 

Ammonium sulphide solution white precipitate of zinc sulphide, ZnS, from neutral or alkaline solutions it is insoluble in excess reagent, in acetic acid, and in solutions of caustic alkalis, but dissolves in dilute mineral adds. The precipitate thus obtained is partially colloidal it is difficult to wash and tends to run through the filter paper, particularly on washing. To obtain the zinc sulphide in a form which can be readily filtered, the precipitation is conveniently carried out in boiling solution in the presence of excess ammonium chloride, the precipitate is washed with dilute ammonium chloride solution containing a little ammonium sulphide. 

Sulphate, (i) BaCl2 solution and dilute HC1 test, and reduction to sulphide test for latter with sodium nitroprusside or lead acetate solution (IV.24, 1). (ii) Lead acetate test and solubility of PbS04 in ammonium acetate solution (IV.24, 2). 

Ammonium Polysulphide Solution dissolve a sufficient quantity of precipitated sulphur in ammonium sulphide solution to produce a deep orange solution Ammonium Sulphide Solution saturate 120 ml of 5M ammonia with washed hydrogen sulphide and add 80 ml of 5M ammonia It should be recently prepared p-Anisaldehyde Reagent dissolve 0 5 ml of p-anisaldehyde in 50 ml of acetic acid and 1 ml of hydrochloric acid... 

Fhenylmercuric sulphide. —Fhenylmercuric acetate is dissolved in ammonium hydroxide—ammonium acetate solution, and treated with hydrogen sulphide or an alkali sulphide, when phenylmercuric sulphide is precipitated as a white amorphous powder. It is insoluble in water or alcohol but dissolves in chloroform, this solution soon decomposing. Hydrochloric acid liberates hydrogen sulphide, and continued boiling witli alcohol gives mercuric sulphide and mercury diphenyl. Heated to 108° C. the compound blackens and decomposes. 

The stability of the mercurated a-naphthols to vards alkali halides decreases from the chlorides to the iodides, potassium iodide eliminating the mercury as mercuric iodide. Diacetoxymercuri-a-naphthol is stable to ammonium sulphide. 2 Acetoxymercuri-1 4-naphthoi monosuiphonic acid is very stable towards ammonium sulphide, but w hen warmed with sodium chloride in acetic acid solution, mercury is split out, and l-acetoxymercuri-2 6-naphthol sulphonic acid has similar properties. l-Acetoxymercuri-jS-naphthol is not blackened by cold ammonium sulphide, but gives mercuric sulphide on heating. 

Six grams of the sodium salt of the acid in 50 c.c. of water are treated with 6-4 grams of mercuric acetate in 50 c.c. of water, and after long standing yellowish-brown bushy needles separate. These after several crystallisations from dilute acetic acid become white. The product obtained is the sodium salt of the acid, and it is very stable towards ammonium sulphide, although this stability is reduced in the presence of sodium chloride. When warmed with sodium chloride in acetic acid solution, mercury is split off. Attempts to prepare a diacetoxy compound have been unsuccessful. 

Two grams of the ethyl ester (1 mol.) in 10 c.c. of metliyl alcohol are added to 8 grams of mercuric acetate (2 mols.) in 50 c.c. of the same solvent, and the mixture allowed to stand for a day. A pale yellow, non-crystalline product separates out, and this is filtered and washed with methyl alcohol and ether. Yield 7 7 grams, 93 per cent. It cannot be rccrystallised, melts about 245 C., and is soluble in ammonium hydroxide, acetic add or mineral acids, but with decomposition in latter in the usual organic solvents it is practically insoluble. Its acetic acid solution after neutralisation with ammonium hydroxide splits off mercuric sulphide when treated with cold ammonium sulphide. 

Isatin forms a blue condensation-product (indophenine) with thiophene. On reduction with ammonium sulphide, isatide C16H12N2O4 [16] is formed. With zinc powder in acetic-acid solution, isatin yields bydroisatinj by more energetic reducing-agents oxy- and dioxy-indol are formed. Chlorine and bromine react with isatin, forming chlorine and bromine derivatives respectively. Acetic anhydride produces an acetyl isatiu [15],... 

Dinitrotriphenylbismuthine dichloride, (C6H4N02)2(C6Hg)BiCl2, occurs when the foregoing compound in acetic acid solution is treated dropwise with concentrated hydrochloric acid. The white precipitate which is formed is filtered off, washed with water and crystallised from benzene, fine needles, M.pt. 136 C., being deposited. On rapid heating the compound explodes. It dissolves readily in chloroform or benzene, is sparingly soluble in ether or acetic acid, insoluble in petroleum ether. When treated with ammonium sulphide it decomposes. 

The deposit was extracted with caustic potash solution and excess of acetic acid and copper acetate solution added dark brown copper apocrenate was precipitated. Ammonium carbonate then precipitated light green copper crenate from the filtrate. By decomposing the copper salts in water by hydrogen sulphide solutions of the acids were formed. These on evaporation in vacuum left amorphous yellow crenic acid and dark brown apocrenic acid. 

Crucibles fitted with permanent porous plates are cleaned by shaking out as much of the solid as possible, and then dissolving out the remainder of the solid with a suitable solvent. A hot 0.1 M solution of the tetrasodium salt of the ethylenediaminetetra-acetic acid is an excellent solvent for many of the precipitates [except metallic sulphides and hexacyanoferrates(III)] encountered in analysis. These include barium sulphate, calcium oxalate, calcium phosphate, calcium oxide, lead carbonate, lead iodate, lead oxalate, and ammonium magnesium phosphate. The crucible may either be completely immersed in the hot reagent or the latter may be drawn by suction through the crucible. 

Alkalies. — The solution of 2 gm. of ammonium phosphate in 100 cc. of water is treated with lead acetate solution in slight excess to precipitate the phosphoric acid, and is then filtered. The excess of lead in the filtrate is then precipitated with hydrogen sulphide, the liquid filtered, the filtrate evaporated to dryness, and the residue ignited. The residue should not be soluble in water, nor should it have an alkaline reaction. 

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