Thiosulfate salts

Organic thiosulfate salts are usually prepared by the reaction of alkyl chlorides with sodium thiosulfate ... 

In contrast to the free acid, stable thiosulfate salts can readily be prepared by reaction of HiS on aqueous solutions of sulfites ... 

Use of a transportable treatment unit to oxidize thiosulfate salts in the Stretford solution to allow them to be recycled in the Stretford process ... 

Gan, J. Detoxification of Halogenated Fumigants by Thiosulfate Salts, Am. Chem. Soc. Meet., Boston, MA. August 18-22, 2002. Prepr. Extd. Abstr. 2002, 42(2) 387-391. 

A representation of the structure of thiosulfuric acid is given in Table 15.8, but the conditions of reaction 15.110 may suggest protonation at sulfur, i.e. (HO)(HS)S02. Thiosulfate salts are far more important than the acid crystallization of the aqueous solution from reaction 15.111 yields Na2S203-5H20. 

The structures of the sulfate and thiosulfate ions are compared in FIGURE 22.21. Thiosulfate salts are used industrially in the paper-making and textile industries and are the fixer solutions in the development of photographic film. 

Take two test tubes. Pour 3 ml concentrated sulfuric acid in the first. In the second test tube add a small sample of the substance being tested to about 5 ml of aluminum molybdenate solution and shake to mix. While holding the first test tube at an angle of 45°, carefully pour some liquid from the second tube to form two liquid layers. If a deep blue ring is seen forming at the sulfuric acid/solution border, the solution contains a thiosulfate salt. 

Detoxification of Some Halogenated Pesticides by Thiosulfate Salts... 

Transformation of HOCs by thiosulfate was first studied in the aqueous phase. It was shown that as the molar ratio of HOCs to thiosulfate salt in water increased, the dissipation of tihe HOCs proportionally accelerated (25, 26). For exanq>le, in solutions containing ammonium thiosulhite at 2.0 mM, the first-... 

The second-order reaction constant k was calculated for fumigants by fitting the measured data to the second-order kinetic model (Table 1). Good correlation was found for all fimigants except for chloropicrin, with correlation coefficients r. 99 (Table 1). This suggests that die reaction between HOCs and thiosulfate salt in aqueous solution follows second-order kinetics typically exhibited by Sn2 reactions. 

Figure 3. Consumption of propargyl bromide (ImM) and thiosulfate (2mM) and accumulation of bromide in aqueous phase during propargyl bromide transformation by thiosulfate salt (28)...

Figure 5. The initial step of nucleophilic dehalogenation reaction between alachlor and thiosulfate salts (A) and fumigants and thiosulfate salts (B)...

CaCla) was then punned into the columns to leach the herbicides, and die leachate was collected in fractions and quantified for herbicide concentration on HPLC. Addition of ammonium thiosulfate to the saturated soil or sand columns essentially prevented propachlor or alachlor from appearing in the leachate, achieving 100% removal of the herbicide as conqtared with the untreated columns (Figure 7). This sinq>le demonstration indicates that diiosulfate salts may be introduced into polluted soil or aquifer systems to detoxify HOC contaminants that are otherwise diffrcult to remove. The introduction of thiosulfate salts may be easily achieved by injection through wells or by leaching in through controlled surface irrigation. 

Secondary Reactions. Besides elemental sulfur, soluble sulfate and thiosulfate salts will accumulate in the liquor due to the following four reactions ... 

Excessive accumulation of sulfate and thiosulfate salts in the Stretford liquor... 

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