Carbon disulfide, conversion

Solvent peak areas are compared to the calibration curves to determine the concentration of each solvent in the sample. The response of the blank is also converted to concentration and subtracted from the sample concentration. The blank includes the background of carbon disulfide as well as the background related to the charcoal tube. With the concentration as ul of solvent/ml of carbon disulfide, conversion to PPM of solvent/volume of air sampled is determined by the following equation ... 

Gaseous Effluents. Twenty percent of the carbon disulfide used in xanthation is converted into hydrogen sulfide (or equivalents) by the regeneration reactions. Ninety to 95% of this hydrogen sulfide is recoverable by scmbbers that yield sodium hydrogen sulfide for the tanning or pulp industries, or for conversion back to sulfur. Up to 60% of the carbon disulfide is recyclable by condensation from rich streams, but costly carbon-bed... 

Conversion of carbon in the coal to gas is very high. With low rank coal, such as lignite and subbituminous coal, conversion may border on 100%, and for highly volatile A coals, it is on the order of 90—95%. Unconverted carbon appears mainly in the overhead material. Sulfur removal is faciUtated in the process because typically 90% of it appears in the gas as hydrogen sulfide, H2S, and 10% as carbonyl sulfide, COS carbon disulfide, CS2, and/or methyl thiol, CH SH, are not usually formed. 

Alternative means for removal of carbonyl sulfide for gas streams iavolve hydrogenation. For example, the Beavon process for removal of sulfur compounds remaining ia Claus unit tail gases iavolves hydrolysis and hydrogenation over cobalt molybdate catalyst resulting ia the conversion of carbonyl sulfide, carbon disulfide, and other sulfur compounds to hydrogen sulfide (25). 

Thermodynamic calculations for reactions forming carbon disulfide from the elements are compHcated by the existence of several known molecular species of sulfur vapor (23,24). Thermochemical data have been reported (12). Although carbon disulfide is thermodynamically unstable at room temperature, the equiHbtium constant of formation increases with temperature and reaches a maximum corresponding to 91% conversion to carbon disulfide at about 700°C. Carbon disulfide decomposes extremely slowly at room temperature in the absence of oxidizing agents. 

At 400—700°C, equihbrium exceeds 99.9% (24). About 5—10% excess sulfur is usually maintained in the reaction mixture to promote high methane conversion and to minimize by-product yield. Carbon disulfide is also formed by the following reaction that is 80% complete at equihbrium at 700°C (47) ... 

Due to the presence of hydrocarbons in the gas feed to the burner section, some undesirable reactions occur, such as the formation of carbon disulfide (CS2) and carbonyl sulfide (COS). A good catalyst has a high activity toward H2S conversion to sulfur and a reconversion of COS and CS2 to sulfur and carbon oxides. Mercaptans in the acid gas feed results in an increase in the air demand. For example, approximately 5-13% increase in the air required is anticipated if about 2 mol% mercaptans are present. The increase in the air requirement is essentially a function of the type of mercaptans present. The oxidation of mercaptans could be represented as ... 

Carbethoxycyclohexanone, 46, 82 2-Carbethoxycyclononanone, 47, 22 2-Carbethoxycyclooctanone, 47, 20 2-Carbomethoxycyclopentanone, conversion to 2-benzyl-2-carbometh-oxycyclopentanone, 45, 8 Carbon disulfide, reaction with /i-chloro-aniline and aqueous ammonia,... 

They also synthesized polymeric iniferters containing the disulfide moiety in the main chain [149,150]. As shown in Eq. (30),polyphosphonamide,which was prepared by the polycondensation reaction of phenyl phosphoric dichloride with piperadine, was allowed to react with carbon disulfide in the presence of triethylamine, followed by oxidative coupling to yield the polymeric iniferter 32. These polymeric iniferters were used for the synthesis of block copolymers with St or MMA, with the composition and block lengths controlled by the ratio of the concentration of the polymeric iniferter to the monomer or by conversion. The block copolymers of polyphosphonamide with poly(St) or poly(MMA) were found to have improved flame resistance characteristics. 

Iron Sponge Also called Dry box. An obsolete process for removing hydrogen sulfide from gas streams by reaction with iron oxide monohydrate. The ferric sulfide that is formed is periodically re-oxidized to regenerate ferric oxide and elemental sulfur. When this process becomes inefficient because of pore-blockage, the sulfur is either oxidized to sulfur dioxide for conversion to sulfuric acid, or is extracted with carbon disulfide. 

A gas-phase reaction between methane (A) and sulfur (B) is conducted at 600°C and 101 kPa in a PFR, to produce carbon disulfide and hydrogen sulfide. The reaction is first-order with respect to each reactant, with kB = 12 m3 mol 1 h-1 (based upon the disappearance of sulfur). The inlet molar flow rates of methane and sulfur are 23.8 and 47.6 mol h 1, respectively. Determine the volume (V) required to achieve 18% conversion of methane, and the resulting residence or space time. 

The present procedure2 describes the conversion of resin-bound, primary aliphatic amines into isothiocyanates and the conversion of the latter into 3-aminothiophenes. The generation of isothiocyanates is related to known procedures,3 in which amines are first treated with carbon disulfide and the resulting dithiocarba-mates are desulfurized by treatment with a condensing agent (alkyl chloroformates, carbodiimides, lead or mercury salts, etc.). The presence of resin-bound isothiocyanates on the polystyrene support could be qualitatively ascertained by infrared spectroscopy (KBr-pellet strong absorption at 2091 cm-1). 

The byproduct obtained from the overall reaction is carbon disulfide (CS ). The reaction between CH and H S given with Eq. 5.47 is the well-known methane process for production of CSj. Most commercial CH -snlfur processes employ silica gel/aluminum catalyst for CSj production. The reaction of CH with sulfur is thermodynamically favorable for CSj formation, and conversion is usually in the range of 90 to 95% with respect to methane (Arpe, 1989). The industrial CH -sulfur pro-... 

Biological. Odeyemi and Alexander (1977) isolated three strains of Rhizobium sp. that degraded thiram. One of these strains, Rhizobium meliloti, metabolized thiram to dimethylamine (DMA) and carbon disulfide, which formed spontaneously from dimethyldithiocarbamate (DMDT). The conversion of DMDT to DMA and carbon disulfide occurred via enzymatic and nonenzymatic mechanisms. 

As stated earlier, all other forms of phosphorus can be made from white phosphorus. Thus, heating white phosphorus first at 260°C for a few hours and then at 350°C gives red phosphorus. The conversion is exothermic and can become explosive in the presence of iodine as a catalyst. When a solution of white phosphorus in carbon disulfide or phosphorus tribromide is irradiated the scarlet red variety is obtained. 

Robert and co-workers (239,240) discovered novel conversions of 2-amino-1,3-dithiolium-4-olates (348) into other mesoionic heterocycles. For example, reaction of 348 with carbon disulfide, phenyl isocyanate, or phenyl isothiocyanate affords l,3-dithiolium-4-thiolates (349), l,3-thiazolium-4-olates (350), and 1,3-thiazolium-4-thiolates (351), respectively. Some of these reactions proceed via the ring-opened ketene tautomer of 348 (240). 

The sulfur plant will also be impacted by minor constituents in the raw gas. Depending upon the primary conversion system utilized, the raw gas may contain sugnificant quantities of cyanides, ammonia, oils, and light hydrocarbons. Sulfur may be present in the forms of carbonyl sulfide, carbon disulfide, mer-captans, thiophenes, or other species. Design engineers should be aware of these species and their variability, in order to provide sufficient protection in the overall system. 

Isothioureas can be prepared on insoluble supports by S-alkylation or S-arylation of thioureas (Entry 7, Table 14.6). Further methods for the preparation of isothioureas on insoluble supports include the N-alkylation of polystyrene-bound, A/,/V -di(alkoxy-carbonyl)isothioureas with aliphatic alcohols by Mitsunobu reaction (Entry 7, Table 14.6) and the addition of thiols to resin-bound carbodiimides [7]. Resin-bound dithio-carbamates, which can easily be prepared from Merrifield resin, carbon disulfide, and amines [76], react with phosgene to yield chlorothioformamidines, which can be converted into isothioureas by treatment with amines (Entry 8, Table 14.6). The conversion of support-bound a-amino acids into thioureas can be accompanied by the release of thiohydantoins into solution (see Section 15.9). The rate of this cyclization depends, however, on the type of linker used and on the nucleophilicity of the intermediate thiourea. 

NMR spectra were taken in deuteriochloroform solution, using a Varian HA100 spectrometer. Thermal measurements were made with a Perkin-Elmer DSC IB differential scanning calorimeter at 40°C/min. Near-infrared spectra were measured in carbon disulfide solution with a Beckman DK 2A spectrophotometer. Gas-chromatographic analyses of reaction mixtures were carried out after conversion of the phenols to trimethylsilyl ethers by reaction with bis (trimethylsilyl) acetamide. 

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