Disulfides manufacturing, sulfides

U.S. manufacturers, 4 834t Carbon disulfide manufacture, 4 828-833 carbonyl sulfide as a by-product of, 23 624 U.S., 4 834t... 

Often an alkyl group is introduced into a larger molecule by building it up from smaller molecules, one or more of which carry the alkyl group. For example, in the manufacture of the alkylated rubber accelerators, tetramethylthiuram disulfide, and sulfide [bis(dimethylthiocarbamyl) disulfide and sulfide], the alkyl groups are introduced as dimethylamine, which is itself a product of alkylation. 

Sulfur, another inorganic petrochemical, is obtained by the oxidation of hydrogen sulfide 2H2S + O2 — 2H2 0 + 2S. Hydrogen sulfide is a constituent of natural gas and also of the majority of refinery gas streams, especially those off-gases from hydrodesulfurization processes. A majority of the sulfur is converted to sulfuric acid for the manufacture of fertilizers and other chemicals. Other uses for sulfur include the production of carbon disulfide, refined sulfur, and pulp and paper industry chemicals. 

Carbonyl sulfide occurs as a by-product ia the manufacture of carbon disulfide and is an impurity ia some natural gases, ia many manufactured fuel gases and refinery gases, and ia combustion products of sulfur-containing fuels (25). It tends to be concentrated ia the propane fraction ia gas fractionation an amine sweetening process is needed to remove it. 

Manufacture. An extensive technology was developed initially ia the 1930s for isolation of ammonium thiocyanate from coke-oven gases, but this technology is no longer practiced ia the United States (372). However, such thiocyanate recovery processes are used iadustrially ia Europe. Likewise, the direct sulfurization of cyanides to thiocyanates is not practiced commercially ia the United States. The principal route used ia the United States is the reaction of carbon disulfide with aqueous ammonia, which proceeds by way of ammonium dithiocarbamate [513-74-6]. Upon heatiag, the ammonium dithiocarbamate decomposes to ammonium thiocyanate and hydrogen sulfide. 

Manufacture of thiophene on the commercial scale involves reactions of the two component method type wherein a 4-carbon chain molecule reacts with a source of sulfur over a catalyst which also effects cyclization and aromatization. A range of suitable feedstocks has included butane, / -butanol, -butyraldehyde, crotonaldehyde, and furan the source of sulfur has included sulfur itself, hydrogen sulfide, and carbon disulfide (29—32). 

Hydrogen sulfide in manufactured gases may range from approximately 2.30 g/m (100 gr/100 ft ) in blue and carbureted water gas to sever hundred grains in coal- and coke-oven gases. Another important sulfur impurity is carbon disulfide, which may be present in amounts varying from 0.007 to 0.07 percent by volume. Smaller amounts of carbon oj sulfide, mercaptans, and thiophene may be found. However, most of the impurities are removed during the purification process and either do not exist in the finished product or are present in only trace amounts. 

Nonmetallic neurotoxins are frequently used in industry in manufacturing of chemicals and resins or as solvents. Some examples are hydrogen sulfide (which paralyzes specifically the nervous centers that control respiratory movement), carbon disulfide, -hexane, methyl -butyl ketone, and acrylamide. Exposure to all of these substances may occur through inhalation of vapors. In addition, carbondisufide and acrylamide may enter the system by dermal absorption. -Hexane and methyl -butyl ketone are not toxic by themselves but are activated by cytochrome P-450 to the neurotoxic hexanedione (CH3COCH2CH2COCH3). 

Methane (CH4) reacts with hydrogen sulfide to yield H2 and carbon disulfide, a solvent used in manufacturing rayon and cellophane ... 

Selenium disulfide, SeS2, may be made by the reaction of selenious acid, H2Se03, and hydrogen sulfide. Its manufacture is described by B.W. Nordlander in US Patents 1,860,154 and 1,860,336. It is prepared in a detergent suspension for therapeutic use. 

Elemental sulfur is mainly used (ca. 85 to 90%) in the manufacture of sulfuric acid. It is also utilized in the production of sulfur dioxide, carbon disulfide, phosphorus(V) sulfide, thiosulfates and sulfur dyes, sulfur-containing putty, gunpowder and fireworks, sulfur concrete, slow release fertilizers and pharmaceuticals and as a rubber vulcanization agent. 

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