Sodium thiosulfate sulfur compounds

In addition to the compounds described in the following paragraphs, see also Hydrogen Sulfide Mercaptan Sodium Thiosulfate Sulfuric Acid Sulfurous Acid Thiocyanic Acid Thiocthcrs Thiophene and Thiourea. 

Sodium thiosulfate is a by-product of the manufacture of Sulfur Black and other sulfur dyes (qv), where organic nitro compounds are treated with a solution of sodium polysulfide to give thiosulfate. The dyes ate insoluble and ate recovered by fUtration. The fUtrate is treated with activated carbon and filteted to obtain a sodium thiosulfate solution. After concentration and crystallization, the final product assays ca 96% Na2S202 5H20 (34) (see Dyes AND... 

Determination. The most accurate (68) method for the deterrnination of copper in its compounds is by electrogravimetry from a sulfuric and nitric acid solution (45). Pure copper compounds can be readily titrated using ethylene diamine tetracetic acid (EDTA) to a SNAZOXS or Murexide endpoint. lodometric titration using sodium thiosulfate to a starch—iodide endpoint is one of the most common methods used industrially. This latter titration is quicker than electrolysis, almost as accurate, and much more tolerant of impurities than is the titration with EDTA. Gravimetry as the thiocyanate has also been used (68). 

In addition to the reactions that produce elemental sulfur, competing reactions also occur that produce undesirable by-products such as sodium thiosulfate. This is detrimental, because the thiosulfate remains in solution, and its concentration can generally be reduced only by bleeding off a portion of the solution inventory. This solution purge waste stream is hazardous, largely because it also contains vanadium compounds. The key to reducing the metal content of the waste stream is to reduce the rate of thiosulfate formation. 

The activity of sulfur towards platinum complexes has led to investigation of so-called rescue agents to ameliorate the side effects of platinum therapy, without compromising its anti-tumor activity. These nucleophilic sulfur compounds include sodium thiosulfate (STS), sodium diethyldithio-carbamate (Naddtc), (S)- 2-[(3-aminopropyl)amino]ethyl phosphorothioic acid (WR-2721, Ethyol , amifostine), glutathione (GSH), methionine, thiourea, cysteine, -acetylcysteine, penicillamine, biotin, sulfathiazole, sodium 2-mercaptoethanesulfonate (mesna), and its dimer (di)mesna (BNP-7787). The protective effect of these compounds is either due to prevention, or reversal of Pt-S adducts in proteins. Some of the more promising of the above-mentioned compounds (see Fig. 1) will be discussed below. 

Sulfur can be effectively removed from a compound, organic or inorganic, by contact with Raney nickel. The action has been described by Aubry (118) as being noncatalytic in nature. One atom of sulfur is removed from sodium thiosulfate in the cold, yielding sodium sulfite from which the sulfur can be completely removed at 100°. Although sulfur can be completely removed from stannous sulfide, it can be only partially removed from antimony sulfide. Following are some of the inorganic compounds from which sulfur removal by use of Raney nickel has been observed (119). 

Procedure Into a suitable beaker, flask, ect., place 250 milliliters (8.5 fluid oz.) of cold water, and then add and dissolve 51 grams (1.8 oz.) of sodium hydroxide. Note sodium hydroxide generates excessive heat when dissolved in water so use caution. Thereafter, add in, in small portions at a time, 50 grams (1.7 oz.) of powdered sulfur, and stir the mixture vigorously during the addition. Note more sulfur may be added if desired. Thereafter, continue to stir the mixture for about 30 minutes. After 30 minutes the mixture is ready for use. Even though the mixture will be contaminated with sodium thiosulfate, it can be used directly in the reduction of nitro compounds. 

The following procedure is used in the analysis of iodoso and iodoxy compounds. In a 200-cc. iodine flask are placed 100 cc. of water, 10 cc. of 6 N sulfuric acid, 2 g. of iodate-free potassium iodide, 10 cc. of chloroform, and finally the sample, about 0.25 g. The flask is shaken for fifteen minutes (or longer, if the reaction is not complete), and then the mixture is titrated with 0.1 N sodium thiosulfate. If the sample is pure the change of color in the chloroform layer may be taken as the end point, but if impurities are present starch must be used, for the impurities impart a brownish color to the chloroform. This solvent is desirable, as it facilitates the reaction with potassium iodide by dissolving the reaction products. Iodosobenzene may be differentiated from iodoxybenzene, for the former reduces iodide ion in a saturated sodium borate solution, whereas the latter does not.1 The reactions involved are ... 

Inorganic sulfur compounds such as sodium metabisulfite, sulfite, and thiosulfate... 

Incompatible with halides anionic emulsifying agents and suspending agents tragacanth starch talc sodium metabisulfite sodium thiosulfate disodium edetate silicates aluminum and other metals amino acids ammonia and ammonium salts sulfur compounds rubber and some plastics. 

---