Coal-based organic chemicals

In addition to supplying transportation fuels and chemicals, products from coal liquefaction and extraction have been used m the past as pitches for binders and feedstocks for cokes [12]. Indeed, the majority of organic chemicals and carbonaceous materials prior to World War II were based on coal technologies. Unfortunately, this technology was supplanted when inexpensive petroleum became available dunng the 1940s. Nevertheless, despite a steady decline of coal use for non-combustion purposes over the past several decades, coal tars still remain an important commodity in North America. 

Findlay M, S Fogel, L Conway, A Taddeo (1995) Field treatment of coal tar-contaminated soil based on results of laboratory treatment studies. In Microbial transformation and degradation of toxic organic chemicals (Eds LY Young, CE Cerniglia), pp. 487-513. Wiley-Liss, New York. 

Acetaldehyde is the product of the Wacker process. At the end of the fifties oxidation of ethene to ethanal replaced the addition of water to acetylene, because the acetylene/coal-based chemistry became obsolete, and the ethene/petrochemistry entered the commercial organic chemicals scene. The acetylene route involved one of the oldest organometallics-mediated catalytic routes started up in the 1920s the catalyst system comprised mercury in sulfuric acid. Coordination of acetylene to mercury(II) activates it toward nucleophilic attack of water, but the reaction is slow and large reactor volumes of this toxic catalyst were needed. An equally slow related catalytic process, the zinc catalysed addition of carboxylic acids to acetylene, is still in use in paint manufacture. 

Reasons for interest in the catalyzed reactions of NO, CO, and COz are many and varied. Nitric oxide, for example, is an odd electron, hetero-nuclear diatomic which is the parent member of the environmentally hazardous oxides of nitrogen. Its decomposition and reduction reactions, which occur only in the presence of catalysts, provide a stimulus to research in nitrosyl chemistry. From a different perspective, the catalyzed reactions of CO and COz have attracted attention because of the need to develop hydrocarbon sources that are alternatives to petroleum. Carbon dioxide is one of the most abundant sources of carbon available, but its utilization will require a cheap and plentiful source of hydrogen for reduction, and the development of catalysts that will permit reduction to take place under mild conditions. The use of carbon monoxide in the development of alternative hydrocarbon sources is better defined at this time, being directly linked to coal utilization. The conversion of coal to substitute natural gas (SNG), hydrocarbons, and organic chemicals is based on the hydrogen reduction of CO via methanation and the Fischer-Tropsch synthesis. Notable successes using heterogeneous catalysts have been achieved in this area, but most mechanistic proposals remain unproven, and overall efficiencies can still be improved. 

It is for these reasons that we have initiated this correlative study of peat petrography and peat industrial-chemical (coal quality) properties. Note that the information reported herein represents preliminary results based on a limited number of different types of peats that were analyzed for only a few coal quality tests (i.e., proximate analysis, ultimate analysis, and BTU content). Future studies will involve measurement of other petrographic parameters and include other industrial analyses (such as, gas and liquid yields, physical properties, organic chemical yields, and so forth). 

In the twentieth century oil overtook coal as the main source of bulk organic compounds so that simple hydrocarbons like methane (CH4, natural gas ) and propane (CH3CH2CHV calor gas ) became available for fuel. At the same time chemists began the search for new molecules from new sources such as fungi, corals, and bacteria and two organic chemical industries developed in parallel— bulk and fine chemicals. Bulk chemicals like paints and plastics are usually based on simple molecules produced in multitonne quantities while fine chemicals such as drugs, perfumes, and flavouring materials are produced in smaller quantities but much more profitably. 

The chemistry of one-carbon molecules (better known as Cj chemistry) is a very exciting area of research for the organometallic chemist. The motivation for these efforts stems from the belief that the raw material base for commercial organic chemicals will shift from oil to coal, in the near future, due to the decline of petroleum reserves. 

The 1973 oil embargo and the ensuing petroleum and natural gas shortages forced the chemical industry to seek new resources for petrochemicals manufacture. About 86% of our domestic carbonaceous fossil fuel resources are coal and only about 2% each are petroleum and natural gas. Thus it is imminent to resort to a coal base for organic chemical products at this time. The manufacture of methanol from natural gas-based synthesis gas is a well-established technology and has been steadily improved over the years. Methanol also can be produced from coal-based synthesis gas in high yield at a... 

Coal tar contains an estimated 10,000 compounds, many of which are important organic chemicals. The use of coal tar as a source of these compounds has been largely relegated to a position below numerous synthetic processes, primarily based on petroleum. Fractionation of coal tar yields the following (approximate temperatures and yields given) ... 

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