Carbon disulfide from methane

Side reactions reduce the yield (99). Proposed processes for obtaining carbon disulfide from hydrogen sulfide and methane include a high temperature plasma (100) and low temperature operation with a catalyst and oxygen (101). 

Use data in Table 7.3 or Appendix 2A to calculate the standard entropy change for each of the following reactions at 25°C. For each reaction, interpret the sign and magnitude of the reaction entropy, (a) The synthesis of carbon disulfide from natural gas (methane) CH4(g) + 4 S(s, rhombic) - CS2(1) +... 

Folkins A process for making carbon disulfide from methane and sulfur at elevated temperature and pressure. A complex separation system removes the hydrogen sulfide from the products so that this sulfur can be re-used. The process can be operated catalytically or non-catalytically. Developed in 1948 by H. 0. Folkins and others at the Pure Oil Company, Chicago. 

The ready availability of carbon disulfide from methane and sulfur in oxide-catalyzed reactions484 [Eq. (3.59)] and its further transformation over zeolites485 [Eq. (3.60)] or other catalysts offer an alternative way to the production of hydrocarbons from methane ... 

Preparation of Carbon Disulfide from Methane and Hydrogen Sulfide. 

The production of carbon disulfide from methane and sulfur vapor can be carried out homogeneously or with a solid catalyst. Also, some solid materials act as a poison, retarding the reaction. The following data were obtained on a flow basis at a constant temperature of 625°C and with an initial reactants ratio of 1 mole of CH4 to 2 moles of sulfur vapor (considered as S2). The first set of data was obtained with the reactor empty (effective volume 67.0 ml), and the second set was obtained after packing the reactor with a granular material (7 mesh) which reduced the void volume to 35.2 ml. 

Figure 5.18 Commericial production of carbon disulfide from methane and sulfur...

Figure 10.39 Manufacture of carbon disulfide from the reaction of methane with sulfur vapor...

Commercial-scale processes have been developed for the production of hydrogen sulfide from heavy fuel oils and sulfur as well as from methane, water vapor, and sulfur. The latter process can be carried out in two steps reaction of methane with sulfur to form carbon disulfide and hydrogen sulfide followed by hydrolysis of carbon disulfide (116). 

The earliest method for manufacturiag carbon disulfide involved synthesis from the elements by reaction of sulfur and carbon as hardwood charcoal in externally heated retorts. Safety concerns, short Hves of the retorts, and low production capacities led to the development of an electric furnace process, also based on reaction of sulfur and charcoal. The commercial use of hydrocarbons as the source of carbon was developed in the 1950s, and it was still the predominate process worldwide in 1991. That route, using methane and sulfur as the feedstock, provides high capacity in an economical, continuous unit. Retort and electric furnace processes are stiU used in locations where methane is unavailable or where small plants are economically viable, for example in certain parts of Africa, China, India, Russia, Eastern Europe, South America, and the Middle East. Other technologies for synthesis of carbon disulfide have been advocated, but none has reached commercial significance. 

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-... 

Clear, colorless, heavy, watery liquid with a strong, sweetish, distinctive odor resembling ether. Odor threshold concentration in air ranged from 21.4 ppm (in a sampled derived from the chlorination of carbon disulfide) to 100.0 ppmv (dervived from the chlorination of methane) (Leonardos et ah, 1969). An odor threshold of 4.68 ppmv was determined by Leonardos et al. (1969). A detection odor threshold concentration of 3,700 mg/m (584 ppmv) was experimentally determined by Dravnieks (1974). The average least detectable odor threshold concentrations in water at 60 °C and in air at 40 °C were 1.08 and 3.6 mg/L, respectively (Alexander et al, 1982). 

Carbon tetrachloride is produced by exhaustive chlorination of a variety of low molecular weight hydrocarbons such as carbon disulfide, methanol, methane, propane, and ethylene dichloride (CEH 1985 lARC 1979). It is also produced by thermal chlorination in the production of tetrachloroethylene. Since the U.S. Food and Drug Administration banned the sale of carbon tetrachloride in any product used in the home, its production initially declined at approximately 8% a year from 1974 to 1981 (HSDB 1992). From 1981 to 1988 the United States consistently produced between 573-761 million pounds (260,000-350,000 metric tons) of carbon tetrachloride per year (C EN 1992 SRI 1988 USITC 1986). Carbon tetrachloride production dropped to 413 million pounds (187,000 metric tons) per year in 1990, and to 315 million pounds (143,000 metric tons) in 1991 (C EN 1992, 1993 USITC 1986, 1991). Carbon tetrachloride is currently manufactured at five facilities in the United States Akzo Chemical, Inc., New York, New York Dow Chemical Company, Midland, Michigan Vulcan Materials Company, Birmingham, Alabama Occidental Chemical Corporation, Dallas, Texas and LCP Chemicals, West Virginia Inc., Moundsville, West Virginia (USITC 1991 HSDB 1992). 

The mechanisms of methane-halogen reactions are chain radical processes. Carbon tetrachloride Is also prepared from carbon disulfide and chlorine. Sulfur is formed in this reaction, but it is recovered and used for the regeneration of CS3. Carbon disulfide is obtained from the elements, but is also formed from methane and sulfur (see Section 1,1.5.4). 

The raw material for much of carbon-sulfur chemistry is carbon disulfide, CS2 ( S=C=S ), a very flaimnable and reactive liquid, mp — 109°C, bp -F46°C, which can be synthesized from elemental carbon or methane and sulfur at high temperatures. Chlorination of carbon disulfide (equation 8) provides a source of carbon tetrachloride on an... 

Dispersive Liquid-Liquid Microextraction The aforementioned SDME method, although it significantly reduces solvent consumption, is not free from drawbacks such as low extraction efficiency and slowly reached equilibrium. In many cases, the extraction efficiency can be increased by using dispersive systems such as the emulsion of organic solvent in an aqueous sample. In dispersive liquid-liquid microextraction (DLLME), a mixture of two solvents (extraction solvent and disperser) is injected by syringe into an aqueous sample. The extraction solvent is a water-insoluble and nonpolar liquid such as toluene, chloroform, dichloro-methane, carbon tetrachloride, or carbon disulfide. A water-miscible, polar solvent, typically acetonitrile, acetone, isopropanol, or methanol, is used as disperser. The typical concentration of extractant in such a mixture is in the range 1-3 %. 

Hydrazones (140) derived from 4-amino-1-methylpiperazine can be reduced by sodium borohydride to l-arylmethylamino-4-methylpiperazine (141) (1708). 1-Methylpiperazine vacuum distilled with formalin gave bis-(l-methylpiperazinyl)-methane, which refluxed with methyl iodide in methanol formed 1,4-dimethyl-piperazine dimethiodide (1709). 1-Methylpiperazine with carbon disulfide in ethanol produced l-dithiocarboxy-4-methylpiperazine, which was reduced by lithium aluminum hydride to 1,4-dimethylpiperazine (1709). 

Ca. 1.3 lO t of carbon disulfide was produced worldwide in I99I, mainly from methane and sulfur. 

Carbon disulfide (CS2) is a liquid that is used in the production of rayon and cellophane. It is manufactured from methane and elemental sulfur via the reaction... 

There are numerous theoretical and experimental results demonstrating that simple molecular solids transform into nonmolecular phases at high pressures and temperatures, ranging from monatomic molecular solids such as sulfur [61], phosphorous [62] and carbon [63] to diatomic molecular solids such as nitrogen [8, 9,40], carbon monoxide [12] and iodine [20, 21], to triatomic molecules such as ice [24, 25], carbon dioxide [10, 31, 37] and carbon disulfide [64, 65] to polyatomics such as methane [27, 28] and cyanogen [11], and aromatic compounds [29]. In this section, we will limit our discussion within a few molecular triatomics first to review the transformations in two isoelectronic linear triatomics, carbon dioxide and nitrous dioxide, and then to discuss their periodic analogies to carbon disulfide and silicone dioxide. 

The industrial solvent carbon disulfide can be made from the reaction between methane and hydrogen sulfide at elevated temperatures using the following reaction gas-phase reaction ... 

Carbon tetrachloride is prepared by chlorinating methane or carbon disulfide. In the latter case the solvent always contains traces of disulfur dichloride or carbon disulfide as impurity it cannot be freed from these contaminants by distillation, but they are removed by vigorous shaking with dilute sodium hydroxide solution.4 Further purification, if necessary, can be effected as for methylene dichloride. All higher chloroalkanes can be purified by essentially the above methods. 

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