Condensation of phenolic groups during coal liquefaction model compound studies

Trewhella, Martin J.; Grint, Alan

doi:10.1016/0016-2361(88)90383-3

Cited by 11 publications

(2 citation statements)

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“…Reactive radicals formed by thermolysis of these groups are considered to contribute to the cross-linking reactions. For −OH functionalities, both radical − and ionic mechanisms have been proposed . Nevertheless, there are arguments as to whether −COOH groups take part in condensation reactions.…”

Section: Introductionmentioning

confidence: 99%

Effects of Water and Molecular Hydrogen on Heat Treatment of Turkish Low-Rank Coals

et al. 1998

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Two low-rank Turkish coals, Tunçbilek (TB) subbituminous and Göynük (GN) lignite, were subjected to low-severity heat treatment with or without added water, under N2 or H2 atmospheres at 285−330 °C, both as original coals and after demineralization with HCl(aq)/HF(aq) treatment. The samples processed in H2−H2O combination seemed to be more dissociated or decomposed than those processed in N2−H2O or under H2 without water. Gas analyses and spectroscopy of samples clearly indicated an effect of water in enhancing decarboxylation reactions and that oxygen rejection from the coals was mainly due to CO2 formation. Water also enhanced the cleavage of aryl−ether bonds. These cleavage reactions are more pronounced in GN coal than in TB coal, probably due to a higher concentration of activated ether structures in the former coal. The disruption of noncovalent interactions is considered mainly responsible for the extensive depolymerization of TB coal. The role of H2 in these heat treatment conditions is considered to be predominantly hydrogenation of polyaromatic sites with the help of mineral matter and scavenging radicals, which arose from cleavage of weak aliphatic ether bonds. The coal samples treated in H2−H2O donated more hydrogen to anthracene during their co-pyrolysis, attributed mainly to a reduced tendency of the treated samples to undergo radical-generating reactions.

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Section: Introductionmentioning

confidence: 99%

Effects of Water and Molecular Hydrogen on Heat Treatment of Turkish Low-Rank Coals

et al. 1998

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“…(1) Condensation of poly(DNap-OH) results in furan formation. 16 (2) Subsequently, the evolution of benzene and aniline induces C–N cleavage in triarylamine. (3) Rearrangement of diarylamine to carbazole simultaneously occurred with the formation of C–C, resulting in a high char-yield.…”

Section: Resultsmentioning

confidence: 99%