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39 Devonian brown coals of Northern Timan are traditionally considered unsuitable for development and industrial use because of their low quality, low power and low calorific value. However, recent finds of remains of primitive quadruped animals, including Devonian tetrapods [1, 6], in Famennian deposits on the Volonga River attracted a new scientific interest in Devonian coal deposits. A distinctive feature of Devonian brown coals of Northern Timan is their low maturity and absence of significant catagenetic transformations of organic matter. Thus, the brown coals of Northern Timan present a source of valuable information about the nature and properties of various components of coalforming plants. Researchers are primarily interested in lignin, which is one of the most chemically stable biopolymers of plant origin. In [4, 5] it was noted the plant polymer of aromatic nature — lignin — played an important role in coal, peat and soil formation. The basis of the chemical structure of lignins is a phenylpropane unit. By composition, all known modern lignins are subdivided into coniferous or guaiacyl (G-type), deciduous or guaiacyl-syringyl (GS-type) and grassy or guaiacyl-syringyl-p-coumaric (GSH-type) (Fig. 1). Until now, the ÓÄÊ: 552/576:547.992.3 DOI: 10.19110/2221-1381-2019-10-39-42

Physical and chemical studies of the organic matter of Upper Devonian brown coals