The ortho-allylbenzyl radical: A sensitive procedure for the assessment of hydrogen donor solvent reactivity
The thermal conversion of coal involves the decomposition of interconnected hydroaromatic structures into resonance stabilized benzylic radical fragments. Capping of these radicals with hydrogen from a donor solvent leads to the formation, in high yields, of lower molecular weight soluble and volatile products. In the absence of a donor solvent, the radicals abstract hydrogen from alkyl coal structures and depending on the supply of donatable hydrogen within the coal, conversion yields may be greatly affected. In view of the great variety of radicals which must form during coal liquefaction and the many possible competing reactions which lead to products, the ability of a donor solvent to transfer hydrogen to coal radicals is undoubtedly of great importance. Although much quantitative data describing the reactions of alkyl and heteroatom radicals with hydroaromatic donor solvents exists, surprisingly little data is available on the reactions of resonance stabilized radicals with hydroaromatic donors. Realizing the importance of this data to the development of a basic understanding of coal conversion chemistry, we have developed a procedure for the quantitative determination of hydrogen donor strengths toward the benzyl radical. The method competes the rearrangement of o-allylbenzyl radical against hydrogen transfer to the radical from a donor solvent. At this time, the method provides relative and estimated absolute rates of hydrogen atom transfer. Experiments are in progress which are designed to convert these relative rates to absolute rates with a high degree of accuracy and precision.
- Research Organization:
- Pacific Northwest Laboratory, Richland, WA
- OSTI ID:
- 6877866
- Report Number(s):
- CONF-830814-
- Journal Information:
- Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States), Journal Name: Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States) Vol. 28:5; ISSN ACFPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
ALKYL RADICALS
AROMATICS
ARYL RADICALS
BENZYL RADICALS
CALCULATION METHODS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
COAL LIQUEFACTION
HYDROCARBONS
HYDROGEN TRANSFER
KINETICS
LIQUEFACTION
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC SOLVENTS
RADICALS
REACTION KINETICS
SOLVENTS
THERMOCHEMICAL PROCESSES
YIELDS