Carbon sulfur

The carbon sulfur bond in LTC4 is formed by the reaction of glutathione (Section 15 13) with leukotriene A4 (LTA4) LTA4 is an epoxide Sug gest a reasonable structure for LTA4... 

Ammonium perchlorate Hot copper tubing, sugar, flnely divided organic or combustible materials, potassium periodate and permanganate, powdered metals, carbon, sulfur... 

PHOSPHAZENES CONTAINING SKELETAL CARBON, SULFUR, AND METAL ATOMS... 

Many types of stainless steels are available. The type most widely used in the dairy industry is 18—8 (18% chromium, 8% nickel plus iron). Small amounts of siHcon, molybdenum, manganese, carbon, sulfur, and phosphoms maybe included to obtain characteristics desired for specific appHcations. 

Hydrogenolysis is analogous to hydrolysis and ammonolysis, which involve the cleavage of a bond induced by the action of water and ammonia, respectively. Chemical bonds that are broken by hydrogenolysis reactions include carbon—carbon, carbon—oxygen, carbon—sulfur, and carbon—nitrogen bonds. An example of hydrogenolysis is the hydrodealkylation of toluene to form benzene and methane ... 

Ultramarine blues are prepared by a high temperature reaction of intimate mixtures of china clay, sodium carbonate, sulfur, siHca, sodium sulfate, and a carbonaceous reducing agent, eg, charcoal, pitch, or rosin. 

Thermal Properties. Thermodynamic stabiUty of the chemical bonds comprising the PPS backbone is quite high. The bond dissociation energies (at 25°C) for the carbon—carbon, carbon—hydrogen, and carbon—sulfur bonds found in PPS are as follows C—C, 477 kj/mol (114 kcal/mol) ... 

The flash point of PPS, as measured by ASTM D1929, is greater than 500°C. Combustion products of PPS include carbon, sulfur oxides, and carbonyl sulfide. Specific hazards are defined by the OSHA Hazard Communication Standard (158). Based on information in 1995, PPS does not meet any of the hazard definitions of this standard. 

The single-monomer route (eq. 5) is preferred as it proves to give more linear and para-linked repeat unit stmctures than the two-monomer route. Other sulfone-based polymers can be similarly produced from sulfonyl haUdes with aromatic hydrocarbons. The key step in these polymerisations is the formation of the carbon—sulfur bond. High polymers are achievable via this synthesis route although the resulting polymers are not always completely linear. 

Census division state Sulfur Nitrogen Carbon Sulfur Nitrogen Carbon Nitrogen Carbon Sulfur Nitrogen Carbon... 

Peroxides. Peroxides are probably the most common materials used after sulfur because of their abiUty to cross-link a variety of diene- and non diene-containing elastomers, and their abiUty to produce thermally stable carbon—carbon cross-links. Carbon—carbon bonds are inherently stronger than the carbon—sulfur bonds developed with sulfur vulcanisation (21). 

Sulfonic acids are prone to reduction with iodine [7553-56-2] in the presence of triphenylphosphine [603-35-0] to produce the corresponding iodides. This type of reduction is also facile with alkyl sulfonates (16). Aromatic sulfonic acids may also be reduced electrochemicaHy to give the parent arene. However, sulfonic acids, when reduced with iodine and phosphoms [7723-14-0] produce thiols (qv). Amination of sulfonates has also been reported, in which the carbon—sulfur bond is cleaved (17). Ortho-Hthiation of sulfonic acid lithium salts has proven to be a useful technique for organic syntheses, but has Httie commercial importance. Optically active sulfonates have been used in asymmetric syntheses to selectively O-alkylate alcohols and phenols, typically on a laboratory scale. Aromatic sulfonates are cleaved, ie, desulfonated, by uv radiation to give the parent aromatic compound and a coupling product of the aromatic compound, as shown, where Ar represents an aryl group (18). 

Carbon—Sulfur Cleavage. The carbon—sulfur bond of DMSO is broken in a number of reactions. Attempts to form the DMSO anion by the reaction of DMSO with sodium result in cleavage accompanied by methane evolution (eqs. 10 and 11) (43) ... 

Incompletely Characterized Carbon Sulfides. A poorly characterized black soHd, known as carsul, occurs as a residue ia sulfur distillation or as a precipitate ia molten Frasch sulfur (12,13). Although this material may approach the composition of a carbon sulfide, it is more likely also to contain some chemically bound hydrogen and possibly other elements. Carbon—sulfur surface compounds of the formula C S, where xis greater than 4,... 

Other burners are used for low capacity operations. A cascade or checker burner, ia which molten sulfur flows down through brick checkerwork countercurrent to a flow of air, is used ia small units with a sulfur trioxide converter to condition gases entering electrostatic precipitators at boiler plants operating on low sulfur coal. A small pan burner, which is fed with soHd, low carbon sulfur, is used to produce sulfur dioxide for solution ia irrigation water to control the pH and maintain porosity ia the soil. The same type of burner is used to disiafect wastewater ia this case sulfur dioxide is used iastead of chlorine. 

Decomposition of Thiols. Thiols decompose by two principal paths (i43— i45). These are the carbon—sulfur bond homolysis and the unimolecular decomposition to alkene and hydrogen sulfide. For methanethiol, the only available route is homolysis, as in reaction 29. For ethanethiol, the favored route is formation of ethylene and hydrogen sulfide via the unimolecular process, as in reaction 30. 

A simplified diagram representing the various reservoirs and transport mechanisms and pathways involved in the cycles of nutrient elements at and above the surface of the Earth is given in Eigure 1. The processes are those considered to be the most important in the context of this article, but others of lesser significance can be postulated. Eor some of the elements, notably carbon, sulfur, chlorine, and nitrogen, considerable research has been done to evaluate (quantitatively) the amount of the various elements in the reservoirs and the rates of transfer. 

Carbon-sulfur bonds can be formed by the reaction of elemental sulfur with a lithio derivative, as illustrated by the preparation of thiophene-2-thiol (201) (700S(50)104). If dialkyl or diaryl disulfides are used as reagents to introduce sulfur, then alkyl or aryl sulfides are formed sulfinic acids are available by reaction of lithium derivatives with sulfur dioxide. 

The rearrangement (automerization) of Dewar thiophene 5-oxide (61), observed by NMR, occurs so much more rapidly than that of the corresponding episulfide that special mechanisms have been invoked. The one which involves a zwitterionic intermediate (Scheme 108) is favored over a pseudopericyclic sulfur-walk mechanism in which the electrons of the carbon-sulfur o--bond and the pair of electrons on sulfur exchange places as the sulfur atom migrates around the ring (80JA2861). 

Scheme 15 shows an example of the cleavage of a carbon-sulfur bond by chlorinolysis. This reaction can also be carried out on the intact penam ring system as shown in Scheme 17 (71JA6269 and the previous paper). In Scheme 18 this reaction is used to form the epimer of... 

Both a carbon-sulfur single bond and a carbon-carbon double bond are oxidized m trifluorovinylsulfurpentafluoride by ozone orair under pressure [II4 (equauon 104)... 

Most of the material presented in this section are reactions of sulfur trioxide. This compound is ambivalent and frequently forms a carbon-sulfur bond (true sulfonation), but it can form a carbon-oxygen bond as well. Examples of both types of bonding are included... 

A one-pot synthesis of alkyl perfluoroalkyl ketones has been developed. Phosphoranes, generated in situ, are acylated with a perfluoroacyl anhydnde, and the resultmg phosphonium salts are hydrolyzed with alkali [4S (equation 48) Hydrolysis of a carbon-sulfur bond in 2-chloro-2,4,4-trifluoro-1,3-dithietane-S-trioxide, which can be obtained from 2,2,4,4-tetrachloro-l,3-dithietane by fluor-mation with antimony trifluoride followed by selective oxidations, opens the nng to produce 2-chloro-1,1,2-trifluorodimethyl sulfone [49] (equation 49)... 

Additions Forming Carbon-Sulfur Bonds by K. B. Baucom... 

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