Mössbauer spectroscopy of iron in coal and coal hydrogenation products

Keisch, B.; Gibbon, Gerst A.; Akhtar, S.

doi:10.1016/0378-3820(78)90011-5

Cited by 19 publications

(5 citation statements)

References 12 publications

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“…The total sulfur or pyrite in coal correlates with an increase in coal conversion. , The pyrite is rapidly transformed into pyrrhotite, and H 2 S is produced from the reduction of pyrite under coal liquefaction conditions. − It has been suggested that H 2 S generated from pyrite is the catalyst for coal liquefaction. , On the other hand, H 2 O is a major product in coal thermolysis and a large amount of H 2 O generates under rather mild coal liquefaction conditions. Since the reactions in coal liquefaction proceed with hydrocracking and hydrogenation by molecular hydrogen and donor solvents, the hydrogen transfer mechanism may be extremely influenced by the presence of H 2 S and H 2 O.…”

Section: Introductionmentioning

confidence: 99%

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H₂S and H₂O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

et al. 1997

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To elucidate the effect of H2S and H2O on hydrogen exchange reactions between tetralin and gaseous hydrogen, the reactions of tetralin with tritiated hydrogen in the presence of H2S or H2O were performed under practical coal liquefaction conditions. The amounts of hydrogen exchange between tetralin and tritiated hydrogen were estimated from hydrogen and tritium balance. The conversions of tetralin in the presence and absence of H2S at 400 °C for 300 min were 4.1 and 3.9%, respectively, while the hydrogen exchange ratio (HER) of tetralin remarkably increased from 4.6% to 40.4% in the presence of H2S and reached 71% at 400 °C for 600 min. It was suggested that the hydrogen exchange mechanism of tetralin with hydrogen in the presence of H2S would include a different mechanism from that in the absence of H2S. It was considered that the H2S molecule acted as both an initiating species and an HS• radical and rapidly abstracted and added hydrogen atom reversibly, promoting the hydrogen exchange in both an aromatic ring and a naphthene ring. In addition to the radical mechanism, the electrophilic exchange with a proton formed from hydrogen sulfide was proposed for the hydrogen exchange mechanism. On the other hand, the conversion and HER of tetralin in the presence of H2O at 400 °C for 300 min were 1.7 and 1.3%, respectively. These values were smaller than those in the absence of H2O. It was considered that H2O inhibited the formation of tetralyl radicals and the hydrogen transfer from tritiated hydrogen to tetralyl radicals. The tritium distribution in H2S reached equilibrium at the initial stage of the reaction, and the hydrogen exchange reaction between gaseous hydrogen and H2S rapidly occurred. However, it was estimated that the hydrogen exchange reaction between gaseous hydrogen and H2O was slower than that with H2S.

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Section: Introductionmentioning

confidence: 99%

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H₂S and H₂O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

et al. 1997

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“…The use of pyrite as a catalyst is greatly complicated by the fact that the pyrite is itself a reactant. Pyrite is readily reduced by H2 at 400 °C to form pyrrhotite according to Keisch et al (1978) FeS2 + H2 -FeS1+r + H2S…”

Section: Methodsmentioning

confidence: 99%

Pyrite-Catalyzed Hydrogenolysis of Benzothiophene at Coal Liquefaction Conditions

Guin¹,

Lee²,

Fan³

et al. 1980

Ind. Eng. Chem. Proc. Des. Dev.

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“…The Mossbauer spectra of coals and coal products were first recorded in 1967 ( 28), and recently interest has revived, both here (29)(30)(31)(32)(33)(34)(35)(36)(37) and in the Soviet Union (38).…”

Section: Mossbauer Spectra Of Coals and Coal Process Productsmentioning

confidence: 99%

Qualitative and Quantitative Analysis of Iron-Bearing Minerals in Fossil Fuels and Petroleum Source Rock by Iron-57 Mössbauer Spectroscopy

Karl

Zuckerman

1981

Advances in Chemistry

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The Mössbauer techniques described here have important advantages over current methods for analyzing coal and petroleum source rock. During the first stage of analysis, the iron-containing minerals are identified by comparing the line positions with values for pure mineral samples. In the second stage, absorption intensities are used to deter mine relative amounts of mineral, and in the final step, absolute amounts of the mineral iron in the sample are found. In oil shales, four iron-containing minerals are predominant: pyrite, dolomite, siderite, and illite. The results are related to those from x-ray diffraction analysis where the correspondence is not always complete. ny spectroscopic method is intrinsically capable of yielding only three types of information: (1) identity-on the basis that identical sys tems behave in an identical way; (2) purity, or the composition of a physical mixture-on the basis that physical mixing does not alter spectro scopic properties; and (3) information concerning structure, bonding, and the forces between molecules. It is a strange commentary that the appli cation of Mossbauer spectroscopy to the first two of this list of three possibilities has come rather late, for these analytical applications would 1 Current address: Degussa Hanau,

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Mössbauer spectroscopy of iron in coal and coal hydrogenation products

Cited by 19 publications

References 12 publications

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H₂S and H₂O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H₂S and H₂O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

Pyrite-Catalyzed Hydrogenolysis of Benzothiophene at Coal Liquefaction Conditions

Qualitative and Quantitative Analysis of Iron-Bearing Minerals in Fossil Fuels and Petroleum Source Rock by Iron-57 Mössbauer Spectroscopy

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Mössbauer spectroscopy of iron in coal and coal hydrogenation products

Cited by 19 publications

References 12 publications

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H2S and H2O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H2S and H2O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

Pyrite-Catalyzed Hydrogenolysis of Benzothiophene at Coal Liquefaction Conditions

Qualitative and Quantitative Analysis of Iron-Bearing Minerals in Fossil Fuels and Petroleum Source Rock by Iron-57 Mössbauer Spectroscopy

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Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H₂S and H₂O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen

Elucidation of Coal Liquefaction Mechanism Using a Tritium Tracer Method. Effect of H₂S and H₂O on Hydrogen Exchange Reaction of Tetralin with Tritiated Molecular Hydrogen