Organic coal structure effect

The effects of exposure of organic solids to particular solvents such as pyridine on their conformational stability can also be Interpreted In terms of the structural features discussed above. How small nucleophilic molecules disrupt Inter- and Intramolecular polar Interactions In coals thereby relaxing the structural matrix and allowing further solvent penetration has been extensively discussed by Peppas (e.g. 11,12), Larsen (1,13) and Marzec (14-16) and their colleagues. Indeed the extent to which exposure to a polar solvent such as pyridine destabilizes a material s molecular structure Is a measure of the extent to which the stability of the material depends on polar Interactions. 

The design of a new generation of conversion processes will require a deeper understanding of coal s intrinsic properties and the ways in which it is chemically transformed under process conditions. Coal properties such as the chemical form of the organic material, the types and distribution of organics, the nature of the pore structure, and the mechanical properties must be determined for coals of different ranks (or degrees of coalification) in order to use each coal type most effectively. 

As previously indicated, in our functionalization studies, we have centered our attention on the vibrational characterization and detection of PAHs. They constitute a family of different chemical compounds with a condensed multibenzene structure. PAHs are important environmental pollutants formed during the incomplete burning of coal, oil and gas, or other organic substances like tobacco or charbroiled meat (79). PAHs can be found as a mixture of different related molecular compounds in air, soil and water due to both natural processes and the human activity. Because many of them have been reported to be strong carcinogens 20-23) it is important to find an effective and selective method for their trace analysis. 

All these methods are specific to the precombustion removal of inorganic sulfur and are expensive when applied to the large quantities of coal burned in power stations. The organic sulfur retained within the carbonaceous structure represents an appreciable contribution to acid rain and, therefore, these methods may not provide effective desulfurization. 

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