Organic chemicals from coal

like crude oil (petroleum), is a fossil fuel which forms over a period of millions of years from the fossilized remains of plants. It is therefore also a nonrenewable resource. However, reserves of coal are several times greater than those of petroleum and, in contrast to petroleum, most European countries have deposits of coal varying from significant to very large quantities. The United States also has large reserves of coal. Extraction and handling of the coal is more difficult, and expensive, than for oil. 

1 Carbonization of coal. Traditionally, and even today to some extent, chemicals have been obtained from coal via its carbonization. This is brought about by heating the coal in the absence of air at a temperature of between 800 and 1200°C, viz. 

The major product by far is the coke, followed by the town gas (a mixture of largely carbon monoxide and hydrogen) with only small amounts of crude 

Coal-tar is a complex mixture of compounds (over 350 have been identified) which are largely aromatic hydrocarbons plus smaller amounts of phenols. The most abundant individual compound is usually naphthalene, but this only comprises about 8% of the coal-tar. Typical weights of major chemicals 

The initial step in the isolation of individual chemicals from coal-tar is continuous fractional distillation (cf. oil) which yields the fractions shown in Table 2.2 

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V. When Organic Chemicals from Coal Tar Were the Frontier... 

Because the processes for making methanol and acetic acid directly from carbon monoxide are commercially proven, it is likely that the decades ahead will see the development of routes to other organic chemicals from coal via methanol. 

Other Organic Processes. Solvent extraction has found appHcation in the coal-tar industry for many years, as for example in the recovery of phenols from coal-tar distillates by washing with caustic soda solution. Solvent extraction of fatty and resimic acid from tall oil has been reported (250). Dissociation extraction is used to separate y -cresol fromT -cresol (251) and 2,4-x5lenol from 2,5-x5lenol (252). Solvent extraction can play a role in the direct manufacture of chemicals from coal (253) (see Eeedstocks, coal chemicals). 

The Chemistry and Technology of Petroleum, James G. Speight The Desulfurization of Heavy Oils and Residua, James G. Speight Catalysis of Organic Reactions, edited by William R. Moser Acetylene-Based Chemicals from Coal and Other Natural Resources, Robert J. Tedeschi... 

Meyers, R. A. Hart, W. D. "Chemical Removal of Organic Sulfur from Coal " Synp. on Removal of Heteroatoms from Fuel, ACS Meeting, Houston, TX, March 23-28, 1980. 

In our work, the removal of organic sulfur from coal was followed by the ASTM procedure. In addition, the fate of iron and sulfur was assessed by a series of extraction experiments with analysis of the solid residues and the liquid extracts by conventional chemical methods. Finally, an instrumental method based on electron microprobe X-ray analysis was used for the direct determination of organic sulfur in the organic coal matrix (18, 19). The analytical results from the different... 

In the United States and most industrialized countries, the practical value of the commercial production of an organic chemical from biomass depends strongly on the availability and price of the same chemical produced from petroleum or natural gas, and occasionally coal. As will be shown shortly, there is no technical barrier that precludes production of commodity chemicals from biomass feedstocks. And it will become evident that many of the more complex organic chemicals are best synthesized from biomass feedstocks or can be extracted from appropriate biomass species. These chemicals can also be synthesized from hydrocarbon feedstocks, but the costs are often prohibitive. In the midst of the fossil fuel era, the less complex, commodity organic chemicals are preferentially manufactured from petroleum or natural gas, whereas complex specialty chemicals are derived from biomass. But commodity organic chemicals are open to entry by biomass feedstocks if they can provide economic advantages. Note that many of the routes described here to commodity chemicals from biomass were in commercial use in the past, are still in commercial use, have recently been commercialized, or have been developed and are available for commercial use. 

The story starts in the early part of this century, in the era before the development of the petrochemical industry, when the major source of organic chemicals was coal. The starting point for many aliphatic compounds then was acetylene (ethyne) whose production utilized coke which was produced from coal. The reactions involved were as follows ... 

The sources of organic compounds are carbon-containing raw materials—petroleum and natural gas, coal, carbohydrates, fats, and oils. In the United States we produce more than 250 billion pounds of organic chemicals from these sources, which amounts to about 1100 pounds per year for every man, woman, and child. About 90% of this 250 billion pounds comes from petroleum and natural gas. Because world reserves of petroleum and natural gas are finite, we will sometime have to rely on other sources to make the vast amount of organic substances that we depend on. 

Around 1900, organic compounds from coal tar became widely available and were used in chemical synthesis, especially in making synthetic dyes. What was the source of the coal tar What were some of the unfortunate occupational health results of this industry ... 

Miller, S.A., Acetylene Its Properties, Manufacture and Uses, Vol. 1, Ernest Benn, London, U.K., 1965, 419. Tedeschi, R.I., Acetylene-based Chemicals from Coal and Other Natural Resources, Marcel Dekker, New York, 1982, 20. Weissermel, K. and Arpe, H.-J., Industrial Organic Chemistry, 4th ed., translated by C.R. Hindley and S. Hawkins, Wiley-VCH, Weinheim, Germany, 2003, 96. 

Toluene is also an important organic chemical Like benzene its early industrial production was from coal tar but most of it now comes from petroleum... 

Cyclic Hydrocarbons. The cyclic hydrocarbon intermediates are derived principally from petroleum and natural gas, though small amounts are derived from coal. Most cycHc intermediates are used in the manufacture of more advanced synthetic organic chemicals and finished products such as dyes, medicinal chemicals, elastomers, pesticides, and plastics and resins. Table 6 details the production and sales of cycHc intermediates in 1991. Benzene (qv) is the largest volume aromatic compound used in the chemical industry. It is extracted from catalytic reformates in refineries, and is produced by the dealkylation of toluene (qv) (see also BTX Processing). 

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