Sodium thiosulfate.pentahydrate

X-ray crystallographic analysis of the sodium thiosulfate pentahydrate [10102-17-7] crystal indicates a tetrahedral stmcture for the thiosulfate ion. The S—S bond distance is 197 pm the S—O bond distance is 148 pm (5). Neutron diffraction of a barium thiosulfate monohydrate [7787-40-8] crystal confirms the tetrahedral stmcture and bond distances for the thiosulfate ion (6). 

Selected physical properties of sodium thiosulfate pentahydrate are shown in Table 1. The crystals are relatively stable, efflorescing in warm, dry air and dehquescing slightly in moist air. They melt in their water of hydration at 48°C and can be completely dehydrated in a vacuum oven at this temperature, or at atmospheric pressure at 105°C. Anhydrous sodium thiosulfate can also be crystallised direcdy from a 72% solution above 75°C. It decomposes at 233°C ... 

Further heating to 440—500°C gives sodium sulfide and sulfur dioxide (33). Table 1. Physical Properties of Sodium Thiosulfate Pentahydrate... 

Specifications. Sodium thiosulfate pentahydrate and the anhydrous salt ate available in various grades, as shown in Tables 2 and 3. 

Health and Safety Factors. The LD q of anhydrous sodium thiosulfate for mice is 7.5 0.752 g/kg (40). Because of low toxicity, it can be safely used iu veterinary medicine. Sodium thiosulfate pentahydrate is affirmed as a GRAS indirect and direct human food ingredient under the Federal Food, Dmg, and Cosmetic Act (41) (see Food additives). 

A 250-mL, two-necked, round-bottomed flask equipped with a magnetic stirbar, thermometer, and a reflux condenser fitted with a rubber septum and balloon of argon is charged with a solution of methyltrioxorhenium (MTO) (0.013 g, 0.05 mmol, 0.1% mol equiv) in 100 mL of methanol (Note 1). Urea hydrogen peroxide (UHP) (14.3 g, 152 mmol) is added (Notes 1, 2, 3, 4), the flask is cooled in an ice bath, and dibenzylamine (9.7 mL, 50.7 mmol) is then added dropwise via syringe over 10 min (Notes 1, 5). After completion of the addition, the ice bath is removed and the mixture is stirred at room temperature (Note 6). A white precipitate forms after approximately 5 min (Note 7) and the yellow color disappears within 20 min (Note 8). Another four portions of MTO (0.1% mol equiv, 0.013 g each) are added at 30-min intervals (2.5 hr total reaction time). After each addition, the reaction mixture develops a yellow color, which then disappears only after the last addition does the mixture remain pale yellow (Note 9). The reaction flask is cooled in an ice bath and solid sodium thiosulfate pentahydrate (12.6 g, 50.7 mmol) is added in portions over 20 min in order to destroy excess hydrogen peroxide (Note 10). The cooled solution is stirred for 1 hr further, at which point a KI paper assay indicates that the excess oxidant has been completely consumed. The solution is decanted into a 500-mL flask to remove small amounts of undissolved thiosulfate. The solid is washed with 50 mL of MeOH and the methanol extract is added to the reaction solution which is then concentrated under reduced pressure by rotary evaporation. Dichloromethane (250 mL) is added to the residue and the urea is removed by filtration through cotton and celite. Concentration of the filtrate affords 10.3 g (97%) of the nitrone as a yellow solid (Note 11). 

A. Sodium isopropylthiosulfate (1). A 5-1., three-necked, round-bottomed flask is equipped with a condenser, a 300-ml. dropping funnel, and a mechanical stirrer. The flask is charged with 123 g. (1 mole) of freshly distilled 2-bromopropane (Note 1) in 1.2 1. of methanol. Water is added slowly with stirring until a slight turbidity develops (Note 2). The stirred mixture is heated to reflux, and 310 g. (1.25 mole) of sodium thiosulfate pentahydrate (Note 3) in 250 ml. of water is added over a period of 30 minutes. The... 

The submitters used sodium thiosulfate pentahydrate supplied by E. Merck A G, Darmstadt, and the checkers used A.C.S. reagent-grade material available from Fisher Scientific Company. 

Sodium thiosulfate pentahydrate Thiosulfuric acid, disodium salt, pentahydrate (8,9) (10102-17-7)... 

Sodium sulfite heptahydrate, 57, 88 Sodium thiosulfate, 56, 120 Sodium thiosulfate, pentahydrate, 58 147, 151... 

Sodium thiosulfate pentahydrate (Na2S203-5H20, formula wt. = 248.17), ACS grade... 

Sodium thiosulfate, pentahydrate, 70-125.0 g Sodium hydroxide, lO.Og Water to make 1.0 liter... 

Table 1. Physical Properties of Sodium Thiosulfate Pentahydrate...

TABLE 2-98 Sodium Thiosulfate Pentahydrate (Na2S203 5H2O)... 

SAFETY PROFILE Moderately toxic by subcutaneous route. Incompatible with metal nitrates, sodium nitrite. When heated to decomposition it emits very toxic fumes of Na20 and SO. See also SODIUM THIOSULFATE and SODIUM THIOSULFATE, PENTAHYDRATE. 

Chloropurine and other heterocyclic halides react with sodium thiosulfate pentahydrate to give 6-sulfanylpurine and the corresponding thiols in good yield.This reaction of halopurine ribosides is general in nature, but effects a deacylation and, therefore, should not be used to obtain blocked nucleosides examples are the formation of 14 and 15,... 

Fluoro-2, 5 -dideoxyuridine-5 -5-thiosulfate (37) was synthesised from 5-fluoro-5 -0-tosylo-2 -deoxyuridine and sodium thiosulfate pentahydrate in ethanol at reflux. This compound is a member of a larger family of analogues of dUMP, dTMP and 5-fluoro-dUMP which have been used to probe interactions with thymidylate synthase. Ethyl chloroformate was shown to be an effective promoter as an alternative to DCC in the preparation of l-[((5)-2-hydroxy-2-oxo-l,4,2-dioxaphosphorinan-5-yl)methyl] cytosine (cyclic HPMPC) from HMPC in large scale quantities and in high isolated yield as well as purity. " ... 

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