Chemicals from Methane

Methane Conversion. Proceedings of a Symposium on the Production of Fuels and Chemicals from Natural Gas, Auckland, April 27-30, 1987 edited by D.M. Bibby, C.D. Chang, R.F. Howe and S. Yurchak Innovation in Zeolite Materials Science. Proceedings of an International Symposium, Nieuwpoort, September 13-17, 1987... 

Watanabe A, Kimura M. Influence of chemical properties of soils on methane emission from rice paddies. Comm. Soil Sci. Plant Anal. 1999 30 2449-2463. 

Methane chemical ionization spectra of ammonium sulfate and ammonium bisulfate are similar to that of sulfuric acid. The elution profile, however, is quite different, as can be seen from Figure 7. If the salts were deposited on the filter in aerosol form, the shape of the elution profile was somewhat narrower and began at a slightly lower temperature compared to the profile obtained when the salt was deposited in aqueous solution from a syringe. In no case, however, did the elution profile of any of the salts tested overlap the profile for sulfuric acid. 

For those familiar with polymer chemistry, polyurethane may be a confusing term. Unlike polyethylene, the polymerization product of ethylene, a polyurethane is not the result of the polymerization of urethane. To add to the confusion, a urethane is a specific chemical bond that comprises a very small percentage of the bonds of a polyurethane. Since we are interested in chemical and physical effects, polyether or polyester is a more descriptive term for the most common bond in a polyurethane. Despite this complication, it is instructive to begin by talking about the methane bond from which the polyurethane name is derived. The general structure or bond that forms the basis of this chemistry is the urethane linkage shown in Figure 2.1. 

Alternatives to fossil fuels, such as hydrogen, are explored in Sections 6.18 and 14.5. Coal, which is mostly carbon, can also be converted into fuels with a lower proportion of carbon. Its conversion to methane, CH4, for instance, would reduce C02 emissions per unit of energy. We can also work with nature by accelerating the uptake of carbon by the natural processes of the carbon cycle. For example, one proposed solution is to pump C02 exhaust deep into the ocean, where it would dissolve to form carbonic acid and bicarbonate ions. Carbon dioxide can also be removed chemically from power plant exhaust gases by passing the exhaust through an aqueous slurry of calcium silicate ... 

Table II. Comparison of 13C Chemical Shifts in Methane Derivatives from ZORA and Pauli Spin-Orbit Calculations8.

Figure 1 Thermodynamic cycle for the enthalpy of formation of methane (CH4) from the standard states of carbon and hydrogen (graphite and H2). The quantities in italics are calculated in typical thermochemical quantum chemical predictions.

In the synthesis of fine chemicals the same types of reaction often employed in the formation of basic chemicals (see Sections 2.5.1 and2.5.2) are used. Furthermore, the same or similar starting materials may be used. There are usually two routes to obtain fine chemicals from C-H transformation that differ with regard to the basic chemicals. One way is to start with a simple substrate e.g. methane and perform a complex functionalization in one step. Most research in the field of fine chemistry is focused in this field. Another way is to start with a more complex starting material and carry out a C-H transformation step with very high selectiv-... 

Almost three thousand organic chemical products are currently derived from petrochemical sources. The commercial syntheses for all these products, however, can be traced back to one of six logical starting points. Consequently, this chapter has been subdivided according to the six major raw material sources chemicals derived from methane, those from ethylene, propylene, C4s, higher aliphatics, and the aromatics. 

Methane is readily available as the major component of natural gas, and its primary use is as fuel. It is also found in coal mines and as a product of anaerobic biological decay of organic materials in swamps and landfills. It is possible to make many chemicals from methane in a laboratory. However, methane is relatively inert chemically and is truly useful as a raw material for only a few commercial... 

On an industrial scale, methane, the main component of natural gas, can easily be converted to formaldehyde. An efficient catalytic condensation of formaldehyde to dihydroxyactone or glycolaldehyde would thus provide a route to C2- and C3-chemicals from methane. The tria-zolin-5-ylidene 94 turned out to be a powerful catalyst for the conversion of formaldehyde (95) to glycolaldehyde (96) in the formoin reaction (Teles et al. 1996). This reactivity is a useful complement to the catalytic properties of thiazolium salts which mainly afford 1,3-dihydroxy acetone as product (Scheme 23) (Castells et al. 1980 Mat-sumoto and Inoue 1983 Matsumoto et al. 1984). As triazolium ylides are much more stable than thiazolium ylids, the elimination of glycolaldehyde occurs faster than the addition of the third formaldehyde molecule. 

Since the samples contained three isotopic isomers with potential variation in enrichment at each position aU three positions needed to be measured separately for each data point. However because of the nature of the structure of the molecule and the resultant fragmentation patterns, none of the three positions could be measured without interference from one or both of the other two. The use of other derivatives, such as the butyl-boronate or trl- methylsUyl derivatives, did not improve this situation. Thus, corrections for the interfering enrichments needed to be made. Both (70eV) electron Impact Ionization (El) and methane chemical ionization (Cl) were used to take advantage of particular fragments or enhanced signal abundances which occurred in each mode. 

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