Sulfane

The H2S sulfanes are the subject of several reviews (129,133). Except for hydrogen sulfide these have no practical utiUty. Sodium tetrasulfide [12034-39-8] is available commercially as a 40 wt % aqueous solution and is used to dehair hides in taimeries, as an ore flotation agent, in the preparation of sulfur dyes (qv), and for metal sulfide finishes (see Leather Mineral recovery and processing). 

The practical importance of the higher sulfanes relates to their formation in sour-gas wells from sulfur and hydrogen sulfide under pressure and their subsequent decomposition which causes well plugging (134). The formation of high sulfanes in the recovery of sulfur by the Claus process also may lead to persistance of traces of hydrogen sulfide in the sulfur thus produced (100). Quantitative deteanination of H2S and H2S in Claus process sulfur requires the use of a catalyst, eg, PbS, to accelerate the breakdown of H2S (135). 

Hydrogen sulfide can react with S2CI2 to produce, depending on conditions, a mixture of sulfanes ( 28 where a > 1) or dichlorosulfanes (S Cl2 where x > 2). These compounds tend to be unstable at ambient temperatures. 

DDD (p,f-TD E) endosulfan and metaboHtes a-endo sulfan- alpha P-endosulfan-beta endosulfan sulfate endrin and metaboHtes endrin... 

Liquid sulfur trioxide may be purchased in stabilized form as Sulfan B," m.p. 17°, b.p. about 45°. Caution must be exercised in handling sulfur trioxide. The liquid is highly corrosive to the skin and the vapor may cause injury if inhaled. The powerful oxidizing and dehydrating effects of sulfur trioxide should not... 

Storage, Handling and Use of Sulfan, Tech. Service Bull. SF-3, General Chemical Division, Allied Chemical and Dye Corporation. 

Hydrogen sulfide is the only thermodynamically stable sulfane it occurs widely in nature as a result of volcanic or bacterial action and is, indeed, a prime source of elemental 8 (p. 647). It has been known since earliest times and its classical chemistry has been extensively studied since the seventeenth century.H28 is a foul smelling, very poisonous gas familiar to all students of chemistry. Its smell is noticeable at 0.02 ppm but the gas tends to anaesthetize the olefactory senses and the intensity of the smell is therefore a dangerously unreliable guide to its concentration. H28 causes irritation at 5 ppm, headaches and nausea at 10 ppm and immediate paralysis and death at 100 ppm it is therefore as toxic and as dangerous as HCN. 

Table 15.12 Some physical properties of poly-sulfanes ...

Azaferrocene reacts with aromatic hydrocarbons in the presence of aluminium chloride, giving rise to the cationic complexes of the type (Ti -arene)(Ti -cyclopenta-dienyl)iron(l+) isolated as BF4 salts [87JOM(333)71]. The complex 28 is obtained by reaction of the sulfane compound [Cp(SMc2)3Fe]BF4 with pentamethyl-pyrrole [88AG(E)579 88AG(E)1468 90ICA(170)155]. The metallic site in this center reveals expressed Lewis acidity (89CB1891). 

Mit Lithiumalanat/Aluminiumchlorid5 Oder besser Lithiumalanat/Bortri-fluorid6 werden Sulfane erhalten z. B. ... 

Oxirane ergeben mit Natrium-trithio-dihydrido-borat Bis-[2-hydroxy-alkyl]-di-sulfane, die mit Lithiumalanat zu 2-Hydroxy-thiolen gespalten werden z.B.4 ... 

Mit einem groBeren Hydrid-OberschuB und bei langerer Reaktionsdauer liefert 1-Oxa-4-thia-spiro[4.5]decan 6 3 % A thy l-cycloh exyl-sulfan neben 20% 2-Cyclohexylthio-athanol... 

Sulfane werden durch Lithiumalanat7, Aluminiumhydrid8 und Diboran9 in der Regel nicht angegriffen. 3-Alkylthio-2-oxo-2,3-dihydro-indole10 und 3-Alkylthio-3H-indole11... 

Das System 2 Lithiumalanat/Titan(IV)-chlorid reduziert Sulfane in THF zu den Koh-lenwasserstoffen2 (Arbeitsvorscbrift s.S. 450). 

Triphenyl-zinnhydrid reduziert thermisch oder mit einem Radikalbildner initiiert Sulfane ebenfalls zu Koh-lenwasserstoffen3. 

Die Reduktion von Dibutyl-sulfon zum Dibutyl-sulfan (68°/0 d.Th.) wird unter energi-scheren Bedingungen in siedendem Toluol durchgefiihrt. 

Natriumboranat/Kobalt(II)-chlorid (s.S. 115) reduziert aliphatische undaroma-tische Sulfoxide in Athanol mit guten Ausbeuten zu den entsprechenden Sulfanen. Mit dieser Methode erhalt man7 z.B. Dibutyl-sulfan (98% d.Th.), Diphenyl-sulfan (95% d. Th.) oder Thiuxanthen (100H/o d. Th.). Dibenzyl-sulfoxid und Tetrahydro-thiophen-1-oxid werden praktisch nicht angegriffen. 

Bei der Reduktion von Dialkyl- und Benzyl-sulfoxiden mit Trichlorsilan in Ather wird ein Gemisch aus Thioacetal und Sulfan erhalten3, in der Gegenwart von a. -Wasserstoff-Atomen lauft also die Reduktion unter Spaltung und Rekombination des Molekiils ab. Dementsprechend werden Diaryl-sulfoxide in Ather praktisch quantitativ zu Sulfanen re-duziert (z.B. Diphenyl-sulfoxid zu Diphenyl-sulfid mit 98% d.Th.). 

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