77-18-8 ammonium thiosulfate

Polyaniline (PANI) can be formed by electrochemical oxidation of aniline in aqueous acid, or by polymerization of aniline using an aqueous solution of ammonium thiosulfate and hydrochloric acid. This polymer is finding increasing use as a "transparent electrode" in semiconducting devices. To improve processibiHty, a large number of substituted polyanilines have been prepared. The sulfonated form of PANI is water soluble, and can be prepared by treatment of PANI with fuming sulfuric acid (31). A variety of other soluble substituted AJ-alkylsulfonic acid self-doped derivatives have been synthesized that possess moderate conductivity and allow facile preparation of spincoated thin films (32). 

Sulfur Complexes. Silver compounds other than sulfide dissolve in excess thiosulfate. Stable silver complexes are also formed with thiourea. Except for the cyanide complexes, these sulfur complexes of silver are the most stable. In photography, solutions of sodium or ammonium thiosulfate fixers are used to solubilize silver hahdes present in processed photographic emulsions. When insoluble silver thiosulfate is dissolved in excess thiosulfate, various silver complexes form. At low thiosulfate concentrations, the principal silver species is Ag2(S203) 2j high thiosulfate concentrations, species such as Ag2(S203) 3 are present. Silver sulfide dissolves in alkaline sulfide solutions to form complex ions such as Ag(S 2 Ag(HS) 4. These ions are... 

Corrosion. Copper-base alloys are seriously corroded by sodium thiosulfate (22) and ammonium thiosulfate [7783-18-8] (23). Corrosion rates exceed 10 kg/(m yr) at 100°C. High siUcon cast iron has reasonable corrosion resistance to thiosulfates, with a corrosion rate <4.4 kg/(m yr)) at 100°C. The preferred material of constmction for pumps, piping, reactors, and storage tanks is austenitic stainless steels such as 304, 316, or Alloy 20. The corrosion rate for stainless steels is <440 g/(m yr) at 100°C (see also Corrosion and corrosion control). 

Uses. The principal use for sodium thiosulfate continues to be as fixative in photography (qv) to dissolve undeveloped silver haUde from negatives or prints. In appHcations where rapid processing is requited, such as the processing of x-ray film, sodium thiosulfate has been largely replaced by ammonium thiosulfate. 

Ammonium thiosulfate, (NH 2S2 3 commonly referred to as ammo hypo, has displaced sodium thiosulfate in photography. It is normally sold in the United States only as the aqueous solution. In addition, a crystal slurry and anhydrous crystal are available in Europe. 

The anhydrous monoclinic crystalline form has a density of 1.679 g/cm (59) no hydrates are known. SolubiUty in water is given in Table 4. Ammonium thiosulfate solutions decompose slowly below 50°C and more rapidly at higher temperatures. The anhydrous salt decomposes above 100°C to sulfite and sulfur (60) ... 

Manufacture. Ammonium thiosulfate has been produced by the reaction of ammonium sulfite with sulfur, sulfides, or polysulfides ... 

Both batch and continuous processes employ excess sulfur and operate at 85—110°C. Trace amounts of polysulftdes produce a yellow color which iadicates that all the ammonium sulfite has been consumed. Ammonium bisulfite is added to convert the last polysulfide to thiosulfate and the excess ammonia to ammonium sulfite. Concentrations of at least 70% (NH 2S2 3 obtained without evaporation. Excess sulfur is removed by filtration and color is improved with activated carbon treatment or sodium siUcate (66). Upon cooling the aqueous concentrated solution, ammonium thiosulfate crystallines. 

Agricultural grades of ammonium thiosulfate are prepared by similar processes and contain some excess sulfur. The sulfur can be removed by washiug with carbon disulfide. A typical sulfur-free product contaius 87% (NH 2S203 3.4% (NH 2SC)3, and 9.6% (NH 2SC)4 (67). 

Ammonium thiosulfate, stable as a solution, is produced ia the form of a 56—60% solution from ammonia and soHd sulfur or an H2S-rich gas stream or both soHd sulfur and H2S gas streams (68). As a result of avadabihty, only development of solutions for processing x-ray and color film and prints has been encouraged. The evolution of automatic processors to develop and print color reinforced the trend toward use of solutions. Most x-ray laboratories and automatic film and print processors require almost immediate results. 

Specifications. The specifications for photographic-grade ammonium thiosulfate are shown in Table 5. There are no corresponding specifications for the agricultural-grade material. 

Table 5. American National Standard Specifications for Photographic-Grade Ammonium Thiosulfate Solution...

Health and Safety Factors (Toxicology). The toxicological properties of ammonium thiosulfate are generally considered to be the same as those of sodium thiosulfate and thiosulfates in general (42). 

Uses. The use distribution of ammonium thiosulfate in 1995 was estimated to be photography, 48% agricultural appHcations, 50% and others, including dechlorination, 2%. 

The principal use of photochemical-grade ammonium thiosulfate continues to be in photography, where is dissolves undeveloped silver haUdes from negatives and prints. It reacts considerably faster than sodium thiosulfate, and the fixing solutions can be used about twice as long as sodium thiosulfate solutions the washing period to remove residual thiosulfate is shorter. 

Agricultural uses for ammonium thiosulfate take advantage of both the sulfur and ammonium content by blending with other nitrogen fertilizers such as urea (71). Some foHar-spray fertilizers contain ammonium thiosulfate together with other metal micronutrients (72,73). Ammonium thiosulfate or mixtures with ammonium nitrate can also be used as desiccants and defoHants ia crop-beariag plants such as cotton (qv), soybean, alfalfa, rice, and peppers (74,75). 

Minor and potential new uses for ammonium thiosulfate include flue-gas desulfurization (76,77), removal of nitrogen oxides and sulfur dioxide from flue gases (78,79), converting sulfur ia hydrocarbons to a water-soluble form (80), and converting cellulose to hydrocarbons (81,82) (see Sulfur REMOVAL AND RECOVERY). 

Calcium thiosulfate has been prepared from calcium sulfite and sulfur at 30—40°C, or from boiling lime and sulfur in the presence of sulfur dioxide until a colorless solution is obtained. Alternatively, a concentrated solution of sodium thiosulfate is treated with calcium chloride the crystalline sodium chloride is removed at low temperature. Concentrated solutions of calcium thiosulfate are prepared from ammonium thiosulfate and lime the Hberated ammonium ion is recycled to the ammonium thiosulfate process (85). 

Other complex thiosulfates have been prepared to study crystal properties, eg, cadmium ammonium thiosulfates (90), NaAgS202 H2O [37954-66-8] (91), I C2Mg(S203)2 -6H20 [64153-76-0] (92), and (NH 2[Ag(S203)JCl2 [12040-89-0] (93). 

The SCOTT process uses an amine to remove the HjS. The acid gas off the amine still is recycled back to the Claus plant. Other types oi processes oxidize the sulfur compounds to SO2 and then convert ihc SO to a secondary product such as ammonium thiosulfate, a fertilizer. These plants can remove more than 99.5% of the sulfur in the inlet stream to the Claus plant and may eliminate the need for incineration. Costs of achieving this removal are high. 

Ammonium acetate Ammonium adipate Ammonium benzoate Ammonium bicarbonate Ammonium biflluoride Ammonium binoxalate Ammonium bisulfate Ammonium bitartrate Ammonium tetraborate Ammonium bromide Ammonium carbonate Ammonium chloride Ammonium citrate Ammonium diclnomate Ammonium fluoride Ammonium fluorosilicate Ammonium gluconate Ammonium iodide Ammonium molybdate Ammonium nitrate Ammonium oxalate Ammonium perchlorate Ammonium picrate Ammonium polysulfide Ammonium salicylate Ammonium stearate Ammonium sulfate Ammonium sulfide (hydrosulfide) Ammonium tartrate Ammonium tliiocyanate Ammonium thiosulfate... 

Selective oxidation of hydrogen sulfide to elemental surfur and ammonium thiosulfate using VO, /Ti02 catalysts... 

VOx supported on TiOi showed good catalytic activity in the selective oxidation of H2S to ammonium thiosulfate and elemental sulfur. V0x/Ti02 catalysts prepared by the precipitation-deposition method can achieve higher vanadium dispersions, and higher H2S conversions compared to those prepared by the impregnation method. 

MRH Aluminium 10.71/33, iron 4.35/50, magnesium 10.88/40, manganese 5.06/50, sodium 5.56/55, phosphorus 7.32/25, sulfur 4.27/20 Mixtures of the chlorate with ammonium salts, powdered metals, phosphorus, silicon, sulfur or sulfides are readily ignited and potentially explosive [1], Residues of ammonium thiosulfate in a bulk road tanker contaminated the consignment of dry sodium chlorate subsequently loaded, and exothermic reaction occurred with gas evolution during several hours. Laboratory tests showed that such a mixture could be made to decompose explosively. A reaction mechanism is suggested. 

See other acmetal derivatives See related platinum compounds 4573. Ammonium thiosulfate... 

Oxidative leaching with ammonium thiosulfate (Section 9.17.3.1) generates solutions containing a mixture of the mono- and di-thiosulfato complexes, [Au(S203)] and [Au(S203)2]3> Gold can... 

Molleman, E. Dreisinger, D. The treatment of copper-gold ores by ammonium thiosulfate leaching. Hydrometallurgy 2002, 66, 1-21. 

ATS [Ammonium thiosulfate] A process for removing residual sulfur dioxide from Claus tail gas by absorption in aqueous ammonia to produce ammonium sulfite and bisulfite. Addition of hydrogen sulfide from the Claus unit produces saleable ammonium thiosulfate. Developed by the Pritchard Corporation and first operated by the Colorado Interstate Gas Company at Table Rock, WY. 

Ammonium thiosulfate solutions, in photography, 19 214 Ammonium tungstate, 25 381-382 Ammonium xylenesulfonate, cosmetic surfactant, 7 834t... 

EPA. 1989c. Environmental Protection Agency. Reportable quantity adjustments Delisting of ammonium thiosulfate. Federal Register 54 33426-33484. 

The formation of S-alkyl thiosulfate (Bunte salt) by the reaction of alkyl halide and sodium thiosulfate has been well known. Whereas a patent claimed the formation of Bunte salt from PECH and sodium thiosulfate (23), the reaction hardly proceeded in DMF owing to low solubility of sodium salt. On the other hand, both ammonium thiosulfate and PECH were soluble in HMPA-H20 (7 1 vol/vol) and the reaction proceeded homogeneously. Water soluble Bunte salt (j2, v(S0), 1200, 1020 cm-1) was isolated by pouring the reaction mixture into water and salting out with ammonium chloride. The DS based on the mercuric nitrate titration was in nearly accord with that on elemental analysis. The DS values depended on the thiosulfate concentration were shown below. 

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