Polysulfane acidity

The polysulfanes were at one time made by fusing cmde Na2S.9H20 with various amounts of sulfur and pouring the resulting polysulfide solution into an excess of dilute hydrochloric acid at — 10°C. The resulting cmde yellow oil is a mixture mainly of H2S (n = 4-7). Polysulfanes can now also be readily prepared by a variety of other reactions, e.g. ... 

The acidity of some polysulfanes in aqueous solution has been estimated by Schwarzenbach and Fischer from the results of elegant titration experiments in a flow apparatus [79]. Using solutions of sodium tetra- and penta-sulfide and measuring the pH value immediately after addition of certain amounts of hydrochloric acid the piCa values were determined as follows ... 

Under special conditions the rapid protonation of aqueous polysulfide ions by hydrochloric acid at temperatures of below 0 °C produces polysulfanes ... 

Since heptasulfane is difficult to prepare, a mixture of polysulfanes known as crude sulfane oil was used instead (average composition H2S6.2, accessible from sodium polysulfide and hydrochloric acid [71]). From 104 g of... 

Crude polysulfanes with x = 7 -12 can be obtained in up to 50% yield at the cathode by reduction of SO2/H2SO4 solutions. The initial reaction product at the cathode is dithionous acid H2S2O4, which decomposes in strong acid to give sulfurous acid and sulfane. Persulfate is obtained at the anode. 

Reaction 2 has also been used to synthesize polysulfanes of thiocarbonic acids,aUcoxythiocarbonic acids, (alkylthio)thiocarbonic acids, or of aUcoxydithiocarbonic acids (xanthates ) (reactions 6-8 with M = H, Na, K and... 

Oxidation of organic polysulfanes by an excess of peroxy acid results in disulfones (polysulfane tetroxides) (equation 153). Polysulfane 1,1-dioxides (monosulfones) may be prepared by reaction of monoorganylthiosulfates with sulfenyl chlorides (equation 156). ... 

Finally, an example of the reactions at a dicoordinated sulfenyl sulfur is presented. The reactions of (alkoxydichloromethyl)(chlorocarbonyl)polysulfanes (11) with Af-methylani-line in CHCI3130 are rationalized by a carbamoyl route where the alkoxydichloromethyl group loses an alkyl chloride as a masked acid chloride, or by a sulfenyl route which reflects fragmentation of the (alkoxydichloromethyl)polysulfanyl compound into the corresponding alkoxy(thiocarbonyl) and sulfenyl compounds 11 (Scheme 15). 

Preparation of S12 from S2CI2 and a polysulfane mixture H2S sulfanes H2S and dichlorosulfanes S Cl2 react with each other with elimination of HCl forming new S-S bonds. Since piue sulfanes with more than two sulfur atoms are difficult to prepare, this synthesis uses a mixture of sulfanes, called crude sulfane oil , which can easily be prepared from aqueous sodium polysulfide and concentrated hydrochloric acid at 0 °C [39, 40] ... 

Aryl- and alkylsulfonated polysiloxanes are available. Aryl sulfonated polysiloxanes are generally synthesized by sulfonation of solid aryl polysiloxanes whereas alkyl sulfonated polysiloxanes are synthesized by starting either with an aqueous solution of the sulfonic acid-functionalized silane or with a highly crosslinked mercapto or polysulfan functionalized polysiloxane. Figure 3 gives an overview of the predominantly synthesized sulfonated siloxane units. 

Acrylonitrile, CH2=CFI-CN, reacts at 80 °C in DMF in the presence of NH3 to give l,7-dicyano-3,4,5-trithiaheptane, (NC-C2Fl4)2S3, in a 49% yield.The latter compound maybe converted to the dicarbonic acid (FI02CC2Fl4)2S3 by hydrolysis in hydrochloric acid (90% yield).Tetrafluoroethylene, C2F4, may be sulfurized by reaction with solid [S8][AsFe]2 at 20 °C after 2 days, ASF3 and a mixture of polysulfanes, (C2Fs)2S with n = 2 (80%), 3 (19%), and 4 (0.5%), had formed. ... 

It is known that HSSO2OH is only the first member of a homologous series of polysulfane monosulfonic acids which can be generated by the reaction of H2Sx with SO3, whereas CF3SSO3H should be the first member of a second homologous series as shown below ... 

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