Record details

Title
    Investigation of low-temperature oxidation of brown coal by electron paramagnetic resonance and infrared spectroscopy
Statement of responsibility
    Eva Šebestová, Vladimír Machovič
Author
    Machovič, Vladimír
    Šebestová, Eva
Language
    anglicky
Source title - monograph
    Weathering of Fossil Organic Matter
Pages
    s. 21-36
Notes
    9 obr., 1 tab., 4 s.bibl.
Subject group
    elektronová paramagnetická resonance
    nízká teplota
    organická substance
    oxidace
    spektrometrie IR
    uhlí hnědé
Geographical name
    ČR-Čechy
    Vřesová (Sokolov)
Keyword
    Brown
    Coal
    Electron
    Infrared
    Investigation
    Low-temperature
    Oxidation
    Paramagnetic
    Resonance
    Spectroscopy
Abstract (in english)
   The present paper deals with the study of low-temperature oxidation of brown coal by electron paramagnetic resonance and by infrared spectrometry. The results are correlated with those of standard test measuring the activity of coal towards oxygen. Low-temperature oxidation of brown coal involves two types of parallel competitive reactions. One of them is the oxidation of coal giving rise to oxygen compounds, the other is the thermal decomposition of labile bonds in the coal - either originally present or formed by the oxidation. The higher the oxidation temperature, the more former reactions predominate over the latter. Increase in the oxidation temperature and/or time is accompanied by a decrease in the concentrations of the paramagnetic centers and aliphatic C-H bonds in the coal, while the carboxyl group content increases significantly. The time behavior of those quantities is not monotonous; instead, it exhibits maxims and minims.
   The oscillatory nature of the reactions was demonstrated by electron paramagnetic resonance and infrared spectroscopy. The changes in the spectral characteristics accompanying the controlled oxidation of the brown coal studied are consistent with the changes in the proneness of the coal to self-ignition, as expressed by the Olpinski index
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    29. 10. 2007
Import date
    8. 8. 2012