Exploratory study of coal conversion chemistry. Final report, May 18, 1981-May 17, 1984. [Solvent mediated hydrogenolysis]

Technical Report · Sat Dec 01 04:00:00 EST 1984

OSTI ID:5724989

Ross, D S; McMillen, D F; Chang, S J; Hum, G P; Green, T K; Malhotra, R

Studies with model compounds demonstrated that very strong bonds can be broken under donor solvent liquefaction conditions. Therefore, the liquefaction of coals under these conditions does not have to be, as traditionally held, dependent on the thermal scission of inherently weak links in the coal structure. These studies also showed that the actual conversions of coal reported by a number of workers show a dependence on donor solvent C-H bond strength that is not in accord with the traditional mechanism, in which the donor solvent operates solely as a scavenger or ''capper'' of thermally generated coal radicals. We have shown that the coal liquefaction effectiveness of various solvents parallels much more closely the observed cleavage of these strong linkages in donor solvent. Therefore, we have suggested that this type of cleavage reaction, which we have labeled ''solvent mediated hydrogenolysis,'' is responsible for the bulk of coal structure fragmentation during donor solvent coal liquefaction. The class of linkages susceptible to the type of cleavage addressed here is very large and almost certainly dominant in coals, no matter what the exact details of their structures turn out to be. For this class of linkage, the results presented here show that cleavage results from the direct bimolecular transfer of hydrogen from hydroaromatic solvent radicals, ArH(dot), to the ipso position of the Ar-X linkage. This sequence is formally hydrogenolysis, but it takes place without the intervention of free hydrogen atoms and therefore without the conditions of high hydrogen pressure and high temperature and/or catalysts that are generally required to provide free H-atoms.

• Research Organization: SRI International, Menlo Park, CA (USA)
• DOE Contract Number: AC22-81PC40785
• OSTI ID: 5724989
• Report Number(s): DOE/PC/40785-12; ON: DE85010393
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL BONDS
CHEMISTRY
CLEAVAGE
COAL
COAL LIQUEFACTION
CRYSTAL STRUCTURE
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
LIQUEFACTION
MATERIALS
MICROSTRUCTURE
MOLECULAR STRUCTURE
ORGANIC SOLVENTS
OXIDES
OXYGEN COMPOUNDS
RADICALS
SOLVENTS
STRUCTURAL MODELS
THERMOCHEMICAL PROCESSES
WATER