Thermal decomposition of aromatic substances
Based on experimental evidence in non-coal systems, and free radical thermochemical kinetics, certain specific features of coal conversion chemistry may be suggested: (1) The first covalent bonds to homolytically cleave upon heating coal are those that generate two resonance stabilized radicals (e.g., benzyl radicals). In fact, under normal liquefaction conditions (approx.< 450/sup 0/C) such bonds will be virtually the only bonds to break in this manner. Other reaction pathways may generate more reactive organic free radicals, however, these can be expected to abstract benzylic H-atoms, thereby producing resonance stabilized radicals. Hence, to a large extent, the free radical chemistry of coal is determined by the chemistry of resonance stabilized radicals. (2) Modes of bond rupture other than simple bond cleavage may be very significant in coal reaction. Two well known free radical pathways, ..beta..-bond scission and free radical displacement occur in 12DPE (and many other) pyrolyses. (3) In view of the relatively high temperatures and free radical concentrations in coal conversion, it might be surmised that free radical isomerizations take place under coal conversion conditions which are not observed in conventional solution phase free radical experiments. (4) The unique ability of tetralin and related compounds to act as effective donor solvents cannot be explained simply by its rate of reaction with free radicals. Two other factors concerning high temperature, free radical reactions of tetralin may help explain its special solvent properties.
- Research Organization:
- West Virginia Univ., Morgantown
- OSTI ID:
- 5203845
- Report Number(s):
- CONF-790917-P3
- Journal Information:
- Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States), Journal Name: Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States) Vol. 24:3; ISSN ACFPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010406* -- Coal & Coal Products-- Pyrolysis & Cracking-- (-1987)
AROMATICS
CARBONACEOUS MATERIALS
CHEMICAL BONDS
CHEMICAL REACTIONS
CHEMISTRY
CLEAVAGE
COAL
COAL LIQUEFACTION
CRYSTAL STRUCTURE
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
HYDROGEN TRANSFER
LIQUEFACTION
MICROSTRUCTURE
ORGANIC COMPOUNDS
PYROLYSIS
RADICALS
TETRALIN
THERMOCHEMICAL PROCESSES