Investigation on the biosolubilization of brown coal using pyrolysis-gas chromatography-mass spectrometry and in situ- alkylation with tetraethylammonium hydroxide (TEAH)

摘要

Brown coal of the Lower Rhine basin has been used for the biosolubilization experiments using Lentinula edodes and Trametes versicolor. Studying the coal fractions and residues remaining after coal biosolubilization by pyrolysis-gas chromatography-mass spectrometry using tetraethylammonium hydroxide (TEAH) at 610°C show significant alteration of coal's organic matter. The assemblage of fatty acid esters released during the pyrolysis varies depending on the investigated coal fraction and the used fungi. Further, ethyl derivatives of aromatic ethers and acids as well as dicarbonic acid ethyl diesters gain an insight into the metabolism pathways of the biosolubilization process of brown coal. Therefore TEAH was used in these thermochemolysis experiments instead the more common tetramethylammonium hydroxide (TMAH). The reaction of TEAH with free hydroxyl and carboxyl groups yield the ethyl derivatives which can be easily identified and differentiated from their methyl homologues by mass spectrometry. In situ--alkylation with TEAH during thermochemolysis of native and biological altered geomacromolecules offers a differentation between free hydroxyl groups and their methylated counterparts and substances, which are attached to humic substances via ester or ether bridges.