Laboratory Oxidation of Fossil Organic Matter Studiedby in situ Infrared Spectroscopy, Rock-Eval Pyrolysis and Pyrolysis-Gas Chromatography-Mass Spectrometry

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Title:Laboratory Oxidation of Fossil Organic Matter Studiedby in situ Infrared Spectroscopy, Rock-Eval Pyrolysis and Pyrolysis-Gas Chromatography-Mass Spectrometry
Creators:
Čejka, Jiří
Sobalík, Zdeněk
Kříbek, Bohdan
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 62, 2, pp. 364-374
Uncontrolled Keywords:Pyrolysis-GC-MS, Fossil organic matter, <i>in situ</i> FTIR monitoring

Abstract

Fossil organic matter in Miocene and Silurian sediments was subjected to experimental oxidation, which was investigated by Rock-Eval pyrolysis, the "off-line" pyrolysis-gas chromatography-mass spectrometry combination, and continuous FTIR monitoring. The pyrolysate yield decreased during the oxidation particularly in the low-matured, predominantly aliphatic organic matter from the Miocene sediments (type I kerogen, algae-type kerogen). This suggests that aliphatic chains are preferentially oxidized, which is in agreement with the marked decrease in the intensity of the <i>v</i>(CH<sub>2</sub>) and <i>v</i>(CH<sub>3</sub>) IR bands. The n-alkane distribution in the chromatographic profile was unaffected by the oxidation; hence, the oxidation of the alkane chains was not selective. At the same time, the bands within the 1 900-1 550 cm<sup>-1</sup> range grew in intensity for both the aliphatic and mixed-type (type II kerogen) organic matter. The oxidation of the aromatic (humic) type of organic fossil matter in the Miocene sediments (type III kerogen, coal-type kerogen) was only accompanied by very small changes in the FTIR spectra. The results of the "of-line" pyrolysis are consistent with those of the Rock-Eval pyrolysis. For all samples, the oxidation was accompanied by a gradual decrease in the hydrogen index (<i>HI</i>) as well as in the pyrolysis temperature maximum (<i>T</i><sub>max</sub>). The changes in the <i>S</i><sub>2</sub>/<i>S</i><sub>1</sub> ratio ("bound"-to-"free" hydrocarbons) indicate that the "free" hydrocarbons in the rocks are preferentially oxidized during the first 8-16 h of the experimental run. Subsequently, hydrocarbon chains involved in the kerogen macromolecule are attacked.

Title:Laboratory Oxidation of Fossil Organic Matter Studiedby in situ Infrared Spectroscopy, Rock-Eval Pyrolysis and Pyrolysis-Gas Chromatography-Mass Spectrometry
Creators:
Čejka, Jiří
Sobalík, Zdeněk
Kříbek, Bohdan
Uncontrolled Keywords:Pyrolysis-GC-MS, Fossil organic matter, <i>in situ</i> FTIR monitoring
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:62
Number:2
Page Range:pp. 364-374
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19970364UNSPECIFIED
ID Code:1123
Item Type:Article
Deposited On:06 Feb 2009 17:06
Last Modified:06 Feb 2009 16:06

Citation

Čejka, Jiří; Sobalík, Zdeněk; Kříbek, Bohdan (1997) Laboratory Oxidation of Fossil Organic Matter Studiedby in situ Infrared Spectroscopy, Rock-Eval Pyrolysis and Pyrolysis-Gas Chromatography-Mass Spectrometry. Collection of Czechoslovak Chemical Communications, 62 (2). pp. 364-374. ISSN 0010-0765

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