Sodium sulfides

LIBERATES HIGHLY TOXIC HYDROGEN SULFIDE ON CONTACT WITH ACID, FLAMMABLE SOLID 

Cubic crystals or granules. Extremely hygroscopic. Discolors on exposure to air.1 

Pentahydrate, Na2S-5H20. Flat, shiny, four-sided, prismatic crystals. Loses three molecules of water at 100°C mp, 120°C (with loss of all water of crystallization). 

Nonahydrate, NaS2-9H20. Tetragonal deliquescent crystals. Odor of hydrogen sulfide. Discolors to yellow, and then brownish black on exposure to light and air mp, 50oC.  

Combustible solid. Finely divided material may explode in air. Reaction with water or acid produces hydrogen sulfide. Carbon dioxide causes release of hydrogen sulfide. Combustion may produce irritants and toxic gases.2 

Reaction of a dihalide with sodium sulfide is perhaps the most direct way of creating a sulfur bridge it has, for example, been used to synthesize the thiophene (8) from a dichloro-substituted precursor (9).9 

Sodium sulfide or hydrosulfide can be used in double Michael additions thus the bridged thiopyran (11) is formed from 2,7-cyclooctadienone (12),12 and dihydrodithiin oxides (13) and related compounds are similarly produced from unsaturated sulfoxides (14).13 

Verboom, M. Schoufs, J. Meijer, H. D. Verkruijsse, and L. Brandsma, Reel. Trav. Chim. Pays-Bas 97, 244 (1978) W. Verboom, R. S. Sukhai, and J. Meijer, Synthesis, 47 (1979). 

Applications Hydrogen sulfide is the starting material for the manufacture of sodium hydrogen sulfide, sodium sulfide and organic sulfur compounds, such as thiophenes or thiols. In several plants hydrogen sulfide is utilized for the production of heavy water. 

Currently most sodium sulfide is still manufactured using the classical reduction of sodium sulfate with coal  

The reaction is carried out in pot furnaces (low brick-lined hearths with lids), continuous furnaces or rotary plate furnaces. The melt produced in the furnace is mashed with water, the undissolved material removed and the solution concentrated to 60 to 62% sodium sulfide by evaporation in cast iron vessels. This concentrated solution solidifies at ca. 90°C. 

In addition to the reduction of sodium sulfate, an electrolysis process is operated in which a sodium polysulfide solution (from sodium sulfide solution and 

Sodium sulfide is also formed by the reaction of hydrogen sulfide with sodium hydroxide. 

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Thus reduction of the 5-thiocyanato group of 151 by zinc (333, 360, 361) or aqueous sodium sulfide (348. 362), hydrolysis of the thiouronium group (7, 363, 364), and deacetylation of the 5-acetylthiothiazole with cold piperidine (365) have been performed to yield the 5-mercapto-thiazole (Scheme 78). It must be pointed out that depending on the experimental conditions, bis(5-thiazolyl(sulfide may be observed as a byproduct (363, 365). Thus 5-amino-4-methylthiazole (152) treated with... 

Butyrolactone with sodium sulfide or hydrosulftde forms 4,4 -thiodibutyric acid (168) with sodium disulfide, the product is 4,4 -dithiodibutyric acid... 

Ryton fibers are high performance products developed by Phillips Petroleum Co. by reaction of -dichloroben2ene with sodium sulfide in the presence of a polar solvent according to the following ... 

Sulfides. The main sulfide of indium is I1I2S2 [12030-24-9], which can be prepared by heating the metal with sulfur or by precipitation from weak acid solutions of indium salts by H2S. Precipitated I1I2S2 varies in color from yellow to red-brown, and in crystal size depending on formation conditions. It dissolves in acids and sodium sulfide solution. Other reported sulfides of indium ate InS [12030-14-7], a red-brown soHd In2S [12196-52-0], and In S [12142-00-5]. 

Unha.iring, Unhairing can be done either by a hair save or a hair pulp system. The hair pulp system is preferred by most tanners for its speed and labor efficiency. In the hair pulp system the hides are treated with sodium sulfide (sulfhydrate) and lime (calcium hydroxide). The hair is quickly destroyed by the strong alkaline reducing conditions. 

Other recovery methods have been used (10). These include leaching ores and concentrates using sodium sulfide [1313-82-2] and sodium hydroxide [1310-73-2] and subsequentiy precipitating with aluminum [7429-90-3], or by electrolysis (11). In another process, the mercury in the ore is dissolved by a sodium hypochlorite [7681-52-9] solution, the mercury-laden solution is then passed through activated carbon [7440-44-0] to absorb the mercury, and the activated carbon heated to produce mercury metal. Mercury can be extracted from cinnabar by electrooxidation (12,13). 

When the mercury present in the atmosphere is primarily in the form of an organic mercury compound, it may be preferable to utilise an aqueous scmbber. This method is particularly useful for control of emissions from reactors and from dryers. For efficient and economical operation, an aqueous solution of caustic soda, sodium hypochlorite, or sodium sulfide is reckculated through the scmbber until the solution is saturated with the mercury compound. 

Soluble sulfides such as sodium sulfide, potassium sulfide, and calcium polysulfides have been used to precipitate mercury salts from alkaline solutions. When this procedure is used, exercise of caution is requked to maintain the pH within a given alkaline range so as to prevent evolution of H2S. Because the solubiUty of mercuric sulfide in water is 12.5 flg/L at 18°C or 10.7 ppb of mercury, use of this method for removal of mercury is adequate for most purposes. However, the presence of excess alkah, such as sodium hydroxide or sodium sulfide, increases the solubiUty of mercuric sulfide as shown ... 

Alkali Treatment. Caustic washing is the treatment of materials, usually products from petroleum refining, with solutions of caustic soda. The process consists of mixing a water solution of lye (sodium hydroxide or caustic soda) with a petroleum fraction. The treatment is carried out as soon as possible after the petroleum fraction is distilled, since contact with air forms free sulfur, which is corrosive and difficult to remove. The lye reacts either with any hydrogen sulfide present to form sodium sulfide, which is soluble in water, or with mercaptans, foUowed by oxidation, to form the less nocuous disulfides. 

Production. Zinc sulfide production started in the United States and in Europe in the 1920s. Starting in the early 1950s, 2inc sulfide, like most white pigments, was slowly replaced by the more superior titanium white. Zinc sulfide can be prepared by a process similar to the one used to manufacture Hthopone. In the first step, barium sulfide reacts with sodium sulfate to produce sodium sulfide solution ... 

In the foUowing step, sodium sulfide reacts with 2inc salts to produce the final product ... 

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