Regioselective hydrogenation of polynuclear heteroaromatic compounds catalyzed by polymer-supported transition metal complexes: initial rates, mechanism of reduction, model coal liquid experiment, role of p-cresol in rate enhancement of nitrogen ring reduction, catalytic transfer hydrogenation

Conference · Sat Jun 01 04:00:00 EDT 1985

OSTI ID:5664333

Fish, R H; Heinemann, H

The research program focused on the utilization of polymer-supported (polystyrene-divinylbenzene, PS-DVB) transition-metal catalysts in the selective catalytic hydrogenation of polynuclear heteroaromatic compounds that are known to be present in coal and coal liquids. We found that the polymer-supported chloro(tristriphenylphosphine)rhodium(l) was the most efficient catalyst for the regiospecific reduction of the nitrogen containing ring in model coal compounds such as quinoline, 5,6 and 7,8-benzoquinoline, and acridine, and in one case, a heteroaromatic sulfur compound, benzothiophene. Interestingly, the polymer-supported rhodium catalyst was more active than the corresponding homogeneous analogue by relative rate factors of 10 to 20 depending on the substrate studied in the reduction. More importantly, a model coal liquid was found to have a relative rate of reduction of quinoline to 1,2,3,4-tetrahydroquinoline (THQ) that was 2.2 times faster than a similar experiment without the coal liquid constituents consisting of pyrene, tetralin, methylnaphthalene, p-cresol, quinoline and 2-methylpyridine. Further experimentation clearly showed that the model coal liquid constituent, p-cresol, was responsible for the relative rate enhancement in the highly regiospecific reduction of quinoline to THQ. Nuclear magnetic resonance spectroscopy (NMR) experiments have given some insight into this rate enhancement phenomena. We also found that 9,10-dihydrophenanthridine was an excellent catalytic transfer hydrogenation reagent in the presence of several homogeneous and polymer-supported transition-metal catalysts to transfer hydrogen to such acceptors as quinoline and acridine. We also evaluated dihydroquinoline as a hydrogen transfer reagent, since THQ has been used as a donor solvent in coal liquefaction experiments. 15 refs., 4 figs., 2 tabs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5664333
• Report Number(s): LBL-19694; CONF-8504130-2; ON: DE85015133
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ACRIDINES
AROMATICS
AZAARENES
AZINES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COAL LIQUIDS
CRESOLS
DATA
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN TRANSFER
HYDROGENATION
HYDROXY COMPOUNDS
INFORMATION
ION EXCHANGE MATERIALS
LIQUIDS
MATERIALS
METALS
NMR SPECTRA
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC ION EXCHANGERS
ORGANIC NITROGEN COMPOUNDS
ORGANIC POLYMERS
ORGANIC SULFUR COMPOUNDS
PHENOLS
PHOSPHINES
PHOSPHORUS COMPOUNDS
PLATINUM METALS
POLYCYCLIC AROMATIC HYDROCARBONS
POLYMERS
POLYOLEFINS
POLYSTYRENE-DVB
PYRIDINES
QUINOLINES
RHODIUM
SPECTRA
STRUCTURAL MODELS
THIONAPHTHENES
TRANSITION ELEMENTS