Coal, source of organic compounds

Oils and coal are great sources of organic compounds and it is a waste merely to burn them as a fuel. Discuss this with specific examples in about 200 words. 

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. 

A (a) What are the principal sources of organic compounds (b) Some chemists argue that the ultimate source of all naturally occurring organic compounds is carbon dioxide. Could this be possible Hint-. Think about the origins of coal, natural gas, and petroleum. 

The largest releases of polycyclic aromatic hydrocarbons (PAHs) are due to the incomplete combustion of organic compounds during the course of industrial processes and other human activities. Important sources include the combustion of coal, crude oil, and natural gas for both industrial and domestic purposes, the use of such materials in industrial processes (e.g., the smelting of iron ore), the operation of the internal combustion engine, and the combustion of refuse (see Environmental Health Criteria 202, 1998). The release of crude oil into the sea by the offshore oil industry and the wreckage of oil tankers are important sources of PAH in certain areas. Forest hres, which may or may not be the consequence of human activity, are a signihcant... 

Other important natural sources of organic chemicals are the so-called fossil fuels - natural gas, petroleum, and coal - all deposited in the earth from the decay of plant and animal remains, and containing thousands of degradation products. Most of these are simple compounds containing only carbon and hydrogen (technically and even reasonably known as hydrocarbons). Natural gas is relatively simple... 

When sources are studied, several things should be done to provide data needed for receptor-model applications. First, particles should be collected In at least two different size fractions corresponding to the division at about 2.5-ym dlam now used In many studies of ambient aerosols. In some cases. It may be desirable to have more size cuts. As noted above, compositions of particles from coal combustion change dramatically below about 0.5-pm dlam (44, 46). Above we Identified a minimum of about twenty elements that should be measured. Also, In order to develop adequate markers for sources that emit carbonaceous particles, measurements of organic compounds and other properties related to carbonaceous particles should be made. 

Two of the major sources of organic material from which organic compounds can be obtained are petroleum and coal. Both of these sources are organic in the old sense because both are products of the decay of plants and animals. Compounds from these sources are used as building blocks for the more complicated organic compounds so important to civilization today. 

Modem civilization consumes vast quantities of organic compounds. Coal, petroleum, and natural gas are primary sources of carbon compounds for use in production of energy and as starting materials for the preparation of plastics, synthetic fibers, dyes, agricultural chemicals, pesticides, fertilizers, detergents, rubbers and other elastomers, paints and other surface coatings, medicines and drugs, perfumes and flavors, antioxidants and other preservatives, as well as asphalts, lubricants, and solvents that are derived from petroleum. 

Ethyne can be used as a starting material for the preparation of many industrially important organic compounds. Currently, it is more cost-effective to prepare these compounds from petroleum. However, as petroleum supplies dwindle in the future, ethyne prepared from coal via calcium carbide will become more economically attractive as a source of these compounds. 

World sulfur reserves. The earth s crust contains about 0.6% S, where it occurs as elemental S (brimstone) in deposits associated with gypsum and calcite combined S in metal sulfide ores and mineral sulfates as a contaminant in natural gas and crude oils as pyritic and organic compounds in coal and as organic compounds in tar sands (Tisdale and Nelson, 1966). The elemental form commonly occurs near active or extinct volcanoes, or in association with hot mineral spings. Estimates by Holser and Kaplan (1966) of the terrestrial reservoirs of S suggest that about 50% of crustal S is present in relatively mobile reservoirs such as sea water, evaporites, and sediments. The chief deposits of S in the form of brimstone and pyrites are in Western European countries, particularly in France, Spain, Poland, Japan, Russia, U.S.A., Canada, and Mexico. World production of S in the form of brimstone and pyrites was approximately 41 Tg in 1973 other sources accounted for about 8 Tg, making a total of 49 Tg (Anon, 1973). Byproduct S from sour-gas, fossil fuel combustion, and other sources now accounts for over 50% of S used by western countries, as shown in Fig. 9.1. This percentage may increase as pollution abatement measures increase the removal of SO2 from fossil fuel, particularly in the U.S.A. Atmospheric S, returned to the earth in rainwater, is also a very important source of S for plants. 

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) ... 

The major sources of aromatic compounds are petroleum and coal tar, a sticky, dark-colored material derived from coal. As with many classes of organic compounds, the simplest structures are the most important commercial materials. 

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 ... 

Coal is the most abundant fossil fuel on Earth and will continue to be an important energy source over the next several hundred years. It is estimated that at present consumption rates coal can last from 216 years to over 500 years [26]. Coal is a complex mixture of organic compounds composed of carbon, hydrogen, oxygen, and smaller amounts of nitrogen and sulfur, as well as moisture and minerals. According to its degree of coalification, coal... 

Plastic materials are based on hydrocarbons, a class of organic compounds that contain hydrogen and carbon. The primary source of hydrocarbons today is crude oil, although it is possible to produce them from coal, shale, or other forms of fossil fuel. It is also possible to produce hydrocarbons from other organic matter, such as cereal grains. 

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