Polysulfides sulfonic acids

Oxidation may be achieved in the presence of oxygen or air. Other suitable oxidants include sulfur, sodium polysulfide, iron (III) chloride, potassium ferro-cyanide (III) or potassium dichromate, peroxydisulfate or salts of aromatic nitro-sulfonic acids. An aqueous/alkaline medium is used in the presence of a high boiling organic solvent which is not miscible with water or which is almost immiscible with water. Cyclization with chlorosulfonic acid can be followed directly by oxidation with bromine to afford the thioindigo system, without separation of the intermediate. 

Reduction of sulfonic acids. P4S,o in sulfolane reduces sulfonic acids (and sulfinic acids) directly to polysulfides in good yield. The products are reduced to thiols by LiAlH4 or NaBH4 (equation 1). 

Many commercial dyes contain one or more sulfonic acid groups to confer water solubility to the dye and assist in binding the dye to the polar fibres in the textile (cotton, nylon, silk, wool, etc.). An example is Congo Red (12) (Figure 3). This is red in alkaline solution thus, the sodium salt will dye cotton red, but it is very sensitive to acids and on acidification the colour changes from red to blue, and so this compound is also used as a type of indicator. Vat dyes, known as sulfur dyes, can be prepared by heating various organic compounds, e.g. amines, aminophenols, and nitrophenols, with sodium polysulfide. 

To describe the full range of thiochemicals is beyond the scope of this entry, which will, therefore, place emphasis on the most common thiochemicals. This entry will cover mercaptans, sulfides, and polysulfides, while the next entry will cover sulfonic acids and its derivatives, some sulfoxides, mercaptoacids and their derivatives. The safety, health, and environmental issues for both entries are discussed at the end of this chapter. 

In straight-run gasohne a variety of sulfur compounds may be present, such as hydrogen sulfide, mercaptans, sulfides, disulfides, polysulfides, and cyclic sulfides. It is also possible that sulfonic acids and alkyl sulfates can be present because of their incomplete removal after refinery treating operations. Likewise there can be a polysulfide content as a result of doctor sweetening. Alkyl sulfates, which are hydrocarbon soluble, can form through the action of sulfuric acid upon olefins. 

Recent efforts in the synthesis of sulfonated aromatic polymers are directed to the polymerization of sulfonated monomers (such as (b), (d), (g), (j), (k), and (1) shown in Scheme 3) [14,15,53,54,96-102] or coupling reactions of sulfonated compoimds with fimctional groups attached to a polymer backbone [ 103,104]. In post-sulfonation, attachment of the sulfonic acid group is restricted to the activated position ortho to the aromatic ether bond, as indicated in Scheme 4a, while in direct polymerization of sulfonated monomers, the sulfonic acid groups are attached to the deactivated site on the ring (Scheme 4b). An enhancement of stabUity toward desulfonation and a modestly higher acidity are expected for the structure shown in Scheme 4b. Recently, polymerization of sulfonated monomers was also used to obtain sulfonated polysulfone (m) via oxidation of a sulfonated polysulfide-polysulfone copolymer [105]. 

As has been indicated in a number of studies, sulfur-containing compounds give a synergic effect with amines and phenols in the stabilization of high-molecular compounds [89, 279]. The following have been proposed and are used as stabilizers of polyvinyl chloride mercaptides of antimony [280, 281], condensation products of aldehydes or ketones with mercaptans [63], thioesters [282], salts of thioacids [283], aromatic esters of aliphatic sulfonic acids [284], esters of xanthic acids [285] the use of the polysulfide of the composition... 

Sulfide of sodium. See Sodium polysulfide Sulfinylbis (methane). See Dimethyl sulfoxide Sulfinyl chloride. SeeThionyl chloride Sulfiram. See Tetraethylthiuram sulfide Sulfisomezole. See Sulfamethoxazole Sulfite lignin. See Lignin sulfonate Sulfoacetic acid, 1-dodecyl ester, sodium salt Sulfoacetic acid dodecyl ester S-sodium salt. See Sodium lauryl sulfoacetate 2-Sulfoanthraquinone sodium salt. See Sodium 2-anthraquinone sulfonate Sulfobenzide. See Diphenyl sulfone o-Sulfobenzimide o-Sulfobenzoic acid imide. See Saccharin... 

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