Baryta solutions, preparation

The baryta solution is prepared from pure crystalline barium hydroxide, Ba(0H)2.8H20, by dissolving in distilled water. Any carbonate is allowed to subside and the clear supernatant liquor syphoned into the storage bottle after the latter has been filled with air free from carbon dioxide. 

The acetyl derivative (each hydroxyl group acetylated) is prepared and purified, and a weighed quantity of it hydrolysed with benzene sulphonic acid. The acetic acid liberated is separated by steam distillation and titrated with baryta solution. 

Tropacocaine (Benzoyl-ili-tropeine), CuHj gOgN, was discovered by Giesel in Java coca leaves and has since been found in Peruvian coca. Its preparation from the former source has been described by Hara and Sakamoto, It crystallises in needles, m.p. 49°, is insoluble in water, but soluble in alcohol, ether or dilute ammonia and is generally prepared by benzoylating /t-tropine, and purified as the hydrochloride. Its alcoholic solution is alkaline and optically inactive. The hydrochloride forms needles, m.p. 271° (dec.), and the hydrobromide leaflets. The aurichloride separates in minute yellow needles, m.p. 208°, from hot aqueous solutions the picrate has m.p. 238-9°. When heated with hydrochloric acid or baryta water the alkaloid is hydrolysed to benzoic acid and -tropine. ... 

Oxychloride of Lead.—This is a compound lately introduced by Mr. Pattison, who has obtained a patent for its manufacture. It is described 5s possessing properties which are superior to those of white lead, inasmuch as it does not so readily blacken with sulphide of hydrogen as the latter body. To prepare it, the patentee dissolves pure chloride of lead in water, at the temperature of 212°, in quantities averaging five-sixths of a pound to a cubio foot of liquid. Soda, potsssa, lime, or baryta in the caustic or hydrated stats, may be employed to precipitate the lead from the solution, but as lime is the cheapest, it is of course preferred. 

To obtain it perfectly free from alumina, Schubert directs hydrate of potassa to be prepared by decomposing the sulphate of that base by means of hydrate of baryta. A solution of this latter salt is added to one of pure sulphate of potassa in exactly sufficient quantity to effect decomposition. Tho decanted solution is then evaporated as previously described. 

Sulphate of Steontia is the celcstini of mineralogists. Sometimes massive, it is often found beautifully crystallized in prisms isotnorphous with sulphate of baryta. Artificially it may be prepared by precipitation from any of its soluble salts, either by sulphuric acid or a soluble sulphate. It has the form of a white tasteless powder soluble in fifteen thousand parts of cold, and three thousand eight hundred and forty parts of boiling water. In solutions of common salt it is slowly but completely soluble.. A solution of sulphate of strontia preoipitatos salts of baryte. The symbol is SrO, SOs Eq. 92-00 specific gravity, 3-95. 

Chromate of Baryta—BaO CiOa—is prepared by dropping a solution of chromate of potassa into a solution of chloride of barium the yellow precipitate must be well washed, and is as Insoluble in water as the sulphate of baryta, ... 

The purity of the gas is tested by explosion analysis (J. C. S., 84, 555) the ratio, contraction on explosion to absorption by baryta water after explosion, should lie between 0-73 and 0-77 (theoretical 0,75). Great care must be taken that this preparation is carried out in the absence of flame, and that neither the apparatus nor the collected gas is exposed to direct sunlight, which decomposes acetylene. Also the cupric chloride solution employed for washing should be kept acid if it becomes alkaline the explosive copper aeetylide is precipitated. Should this occur the solution is mixed with much water and poured away. 

Example.—Mannitol.—The hexa-acetyl derivative (p. 259) is prepared and purified, and a quantity of it—about 0-2 gm.—along with 100 c.cs. of 10% benzene sulphonic acid solution placed in a steam distillation flask. The flask is connected to a condenser on one side and to an apparatus for the generation of pure steam on the other. A suction flask to serve as receiver is attached by a cork to the condenser, and to the side tube of the suction flask a soda-lime tube to prevent the entrance of carbon dioxide is attached. Steam is blown through the flask until (1-5—3 hours) the distillate passing over is neutral. The whole distillate is then titrated with standard baryta, using phenolphthalein as indicator. 

Owing to the fact that very few potassium salts are insoluble in water, it is not convenient to prepare chloric acid from the potassium salt for this purpose it is better to use the barium salt, made from baryta-water and chlorine a solution of this salt, when mixed with the equivalent amount of dilute sulphuric acid, yields a precipitate of barium sulphate, and chloric acid remains in solution. 

Barium Pentachlor-hydroxy-p latinate, BaPtCl6(OH). 4HaO, which is prepared by neutralising a solution of the acid with baryta water. On concentration in a desiccator the salt crystallises out in orange-yellow prisms.4... 

Barium Monohydrate—Ohusftc baryta— BaH,0,—170.8—is prepared the action of H,0 on BaO. It is a white, amoi hous solid, soluble in H,0. Its aqueous solution, boryta loofer, is alkaline, and absorl CO, with formation of a white deposit of BaCO,. 

Preparation of BaMoOi About 50 g. of commercial ammonium molybdate is dissolved in about 300 ml. of boiling H3 (some ammonia is added). This solution is introduced gradually into a solution of 100 g. of Ba(OH)a 8 HgO in 300 ml. of H3O heated on a steam bath. The mixture is heated and stirred for 2-3 hours longer. The white precipitate is washed several times with hot H3O, then heated once more with baryta water [aqueous Ba(OH) 2] and thoroughly washed. 

Perchloric acid was discovered by Count Stadion. He discovered potassium perchlorate in the residue from the preparation of chlorine dioxide from potassium chlorate and concentrated sulphuric acid, correctly determined its composition by decomposing it by heat into oxygen and potassium chloride, and obtained a 70 per cent, solution of perchloric acid ( oxygenated chloric acid ) by distilling potassium perchlorate with somewhat diluted sulphuric acid. He also precipitated the first residue with baryta water to remove sulphuric acid, removed chloride with silver oxide, and evaporated the filtrate in vacuum over concentrated sulphuric acid. Stadion adopted Davy s theory of chlorine. 

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