H. Schmiers et R. Kopsel, MACROMOLECULAR STRUCTURE OF BROWN-COAL IN RELATIONSHIP TO THE DEGRADABILITY BY MICROORGANISMS, Fuel processing technology, 52(1-3), 1997, pp. 109-114
The macromolecular components of two humic brown coals of the same moo
r-facies type, but different geological age were isolated, and their s
tructures were subsequently characterized using solid-state C-13-NMR s
pectra. The results were compared with the published C-NMR data of the
macromolecular components of a brown coal which was rich in liptinite
macerals. As to the humic coals, the proportion of the macromolecular
components is smaller in the older coal than in the younger coal (65%
and 85%, respectively). The NMR spectra show a structure which is rel
ated to lignin structures. Quantitative differences are indicated by t
he smaller proportions of aliphatic oxygen functionalities and the hig
her proportions of alkyl groups in the older coal. The macromolecular
components of the liptinitic brown coal represent a completely differe
nt structural type: Their network has an aliphatic basic structure and
is predominantly built up by linkage of methylene chains. Very differ
entiated structural conditions exist for microbial depolymerization of
the macromolecular structures of brown coals. (C) 1997 Elsevier Scien
ce B.V.