DE422323C - Manufacture of insoluble silver alkali thiosulphates - Google Patents

Description

Production of insoluble silver alkali thiosulphates. It is known and used practically in the processing of photographic plates; that silver salts. The water-insoluble silver halogen compounds, -in Al-Kalithiosulfaten, dissolve easily. It was, in particular through the work of A. Ro-senheim and S. Steinhauser (magazine for inorganic chemistry vol. 25, S. year. I goo). established and confirmed by J. Meye r and H. E nge 1 ing (Ber. d. Deutsche Chem. Ges. Vol. 40. S. 1351. Jahr-. 1907) that different series of salts are obtained from these solutions are eliminated, because those poorer in a'ekatithiosulphate are mostly difficult or insoluble in water, while those rich in alkali thiosulphate dissolve more easily in water. So are z. B. The sodium salt Na, S, 03 # A- S.0, and the potassium salt 5 h., S, 03 are insoluble in water. 3 _1, -_, S = 03. while in water the sodium salt 2 \ a = S = 03 #: 1, -., S = 03 .. 2 H., () and the potassium salt 3 h., S., 03 # A- S., 03. z H. = () are easily soluble. The salts of lithium, rubidium and cesium behave in a similar way, while the solution in ammonium thiosulphate results in more complex compounds which still contain halogen and which were also published by A. Rosenheim and S. Steinhäuser (Zeitschrift für inorganic Chemie Vol. 2 5, S. toi, Year. Ic) oo '@ were made.

Dic in water: easily soluble silver alkali thiosuifate have for the: apeutic purposes have a special meaning. because in them the decidedly germicidal Effect of the silver%, is present. while the corrosive effects of simple silver salts, such as B. the silver nitrate, is eliminated by the complex bond of the metal.

The production of these insoluble salts made after the previous experiences have caused considerable difficulties, since there is also a large excess a dilute alkali thiosulphate solution had to be used, which, as the lyes decompose at higher temperatures with the deposition of sulfur silver, at ordinary temperature had to be concentrated slowly, which took a considerable amount of time required. In addition, the yields by this process were extremely low and the slowly crystallizing salts with an excess of the alkali thiosulphates mixed.

According to the previous production instructions, which are given in the above-mentioned work by A. Rosenheim and S. Steinhäuser, it was only a matter of producing these salts, but not to obtain them pure in the highest possible yield. It was z. B. the sparingly soluble silver sodium thlosulfate (op. Cit. P. 74) obtained by stirring chlorine silver into a concentrated sodium thiosulfate solution in good yield, but the easily soluble salt Ag, S, 03. 2 \ a, p.0i # 2 11., 0 only from the mother liquors of this salt after long standing in the desiccator. and found in very poor yield.

For the production of highly soluble potassium silver thiOsulphate 3 Ag, S., 03. 5 K = S_03 became (op. Cit. P. 7 6) a concentrated solution of isalium thiosutfate with silver nitrate added cooked by potassium carbonate, being Silberox \ d parted, from which was filtered off. Crystallized from the lye the insoluble salt from, naturally - due to the deposition of the Siiberoxvds in moderate Yield.

For the production of the easily soluble Saae. Ag_, S., 03 # 3 Is = S, Oa # a H._0 was silver chloride, in an excess of thiosulphate completely -e: ost and the clear solution is concentrated in the desiccator @ at ordinary temperature.-t, -which-after long standing, especially since the solution decomposed in the long run, a very moderate yield on which easily soluble silver salts was obtained.

A renewed examination of these connections has now shown that the sparingly soluble silver alkali thiosulphates can be found very easily in almost quantitative terms Yield is obtained when adding saturated alkali thiosulfate solutions with vigorous stirring at about 30 ° the calculated amount of silver salts, preferably silver halides, like silver chloride, enters. ' The resulting crystalline precipitate consists of the pure salts of the insoluble series, and its purity can through microscopic examination of the crystal structure established «-erden.

The evacuated and air-dry precipitate is concentrated as possible in a Solution of the same amount of alkali thiosulphate (calculated on anhydrous salt entered with external ice cooling at o ', and this suspension becomes longer stirred at this same temperature. It has been shown that with o 'thereby a conversion of the salts of the sparingly soluble series into those of the easily soluble ones occurs, which can also be easily followed in the microscopic picture of the crystals.

The salt is sucked from the small amount of the lye, with little Covered with ice water, washed with a little alcohol and ether and is then air dry completely stable.

This procedure is different due to the solubility of the = Minor modifications for sodium, lithium, Potassium, rubidium and cesium salts can be used.

It differs in principle from the earlier work regulations, that the sparingly soluble silver alkali metal sulfates limited by working in one Temperature range (up to 3o ') can be obtained in almost quantitative yield and that these salts are used as starting materials for the production of the important easily soluble Salts are used. While namely according to the older information. by A. Rosenheini and S. Steinhäuser made these from dilute solutions of silver salts in excess Alkali thiosulfates in moderate and uncontrollable yield after long standing are obtained, here the almost quantitatively obtained salts of the sparingly soluble Row mixed with a pulp of the calculated amount of Alkalithiosuifaten at o ", without trying from the beginning: -: - :: in a complete solution of the two components will. The discovery that the point of transition of the poorly soluble salts into the Easily soluble at about o, it enables the present method of operation apply and thereby an almost quantitative yield of the easily soluble salts to achieve. This is also made possible by the fact that this is done by the salts of the poorly soluble series and not, as in the past, of other silver salts such as silver chloride or silver nitrate, is assumed.

Embodiment i.

100 kg of 1-Z., S = Oi are dissolved in aoo ccm of water and subjected to strong Stirring at 30 'results in the precipitation of .i5 g of silver nitrate with hydrochloric acid and long, well-washed choral silver entered. After stirring for about two hours became the residue; which was uniformly crystalline, vacuumed and dried; his weight was. 9o g. This was mixed with 90 g of 1 = S, 03, with 65 ccin Mix in ice water and stir for about an hour at o 'in the thermostat. The precipitate is sucked off is drunk; Its weight was 1.2 g, its silver content = 0.5 percent, which is a yield, calculated on silver, of 86.1 percent of that Salts 3 K, S # O3. Ag2S., 03 # 2 H20. Corresponds. Embodiment a.

100 g of sodium thiosulphate N% S = 03 # 5 H., 0, dissolved in 400 ccm of water, are treated all at once with the silver chloride precipitated from 100 g of silver nitrate with hydrochloric acid and washed out acid-free, and the mass is mechanically strong for about one hour touched. The uniformly crystalline precipitate is filtered off with suction and washed thoroughly with cold water. It consists of the sparingly soluble salts Ag, S, 03 # Na, Sz03, of which i, 10 g are obtained. This amount will dry with zoo g sodium thiosulfate NaS.Og # 5 H, O was stirred in a mortar un d- then added with 6o CCIN water, about 2 hours at o ° stirred. After this time, the conversion into the readily soluble sodium salt Ag "S, 03 # = \ a @ S, 03 # ä H; 0 has taken place, of which 168 g with a content of 30 percent Ag. Was obtained, which corresponds to a yield of So percent corresponds to the amount of silver applied.

The potassium thiosulphate liquor of the first process, the end who has deposited the insoluble salt becomes haline thiosulfate until exhaustion used for further representations. the second lukewarm becomes through .Kochen mit The alkali dissolved long silver deposited as sulfur silver and reappeared Processed silver nitrate.

Claims (1)

1 ': wrw @ rn @ srr, i'mna: - i. Process for the production of insolubles Siiber-Alkatitliiosulfate des Sodium, Li- thiums, potassium, rubidium and cesium, characterized by the fact that in con- z-, titrated. on e; «- a 3o- heated alkali tli: osu: fatlö - z-ane: i silver salts, especially silver berha: ogen connections, in approximately calculated \ Ien; e a # -to be touched. _. Method of extraction: calibrated in Water-soluble silver alkali thiosuifate, thereby geke-R marked. that they are difficult solve; ichenZa '! -_ e by stirring with very con- centered a; ka: i: lüosulfat: esungen bei o` in the salts of the easily soluble in water Rows are transferred.