Investigation of mechanisms of hydrogen transfer in coal hydrogenation. Phase I final report, July 1976--December 1977
The objective of this study is to develop an understanding of the mechanism of hydrogen transfer to coal and intermediates during liquefaction. Emphasis has been placed upon hydrogen-transfer reactions of model compounds representative of structural moieties present in or produced from coal at conditions comparable to those used in coal liquefaction. Screening experiments were first undertaken to determine the relative ease of fragmenting C--C, C--N, C--O, and C--S bonds in the presence of a hydrogen-donor solvent. Condensed aromatics, such as benzofuran, were stable at temperatures up to 475/sup 0/C. Non-condensed aromatics, such as dibenzyl, fractured in the range of 400 to 475/sup 0/C. Dibenzyl ether, aromatic sulfides, and compounds having carbonyl and alcohol groups reacted readily at temperatures below 425/sup 0/C. Detailed experimentation using various donors with dibenzyl indicates that the thermal reaction of dibenzyl forming benzyl radicals is rate controlling. Experiments with hetero compounds indicated that the relative order of reactivity is the following: furans < phenols < ketones < aldehydes < chain benzyl ethers < thioethers. The study of hydrogen transfer using either a deuterium atmosphere or deuterium-tagged donor was not successful at temperatures above 400/sup 0/C due to scrambling. Experimentation at lower temperatures with heteroatom containing compounds was successful. It was shown that essentially all of the hydrogen added to the cleaved acceptor comes from the donor solvent or via intramolecular rearrangement and not from dissolved hydrogen. Dissolved hydrogen does serve the role of rehydrogenating the hydrogen depleted donor solvent.
- Research Organization:
- Gulf Research and Development Co., Pittsburgh, PA (USA)
- OSTI ID:
- 6074274
- Report Number(s):
- FE-2305-18
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
010600 -- Coal
Lignite
& Peat-- Properties & Composition
ALDEHYDES
AROMATICS
ARRHENIUS EQUATION
CARBONACEOUS MATERIALS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CLEAVAGE
COAL
COAL LIQUEFACTION
CRYSTAL STRUCTURE
ENERGY SOURCES
ETHERS
FOSSIL FUELS
FUELS
FURANS
HETEROCYCLIC COMPOUNDS
HYDROGEN TRANSFER
HYDROGENATION
HYDROXY COMPOUNDS
KETONES
KINETICS
LABELLED COMPOUNDS
LIQUEFACTION
MAGNETIC RESONANCE
MICROSTRUCTURE
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHENOLS
RADICALS
REACTION KINETICS
RESONANCE
STRUCTURAL MODELS
THERMOCHEMICAL PROCESSES