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Abstract
Coalification is the chemical and physics transformation of the organic matter from lignite to anthracite and it is mainly control by temperature and geological time.
The principal characteristics of thermal reaction is the production of free radicals. Free radicals from aromatic are more stable than free radical from paraffinic structure, so aromatization is the mainly route during the coalification process by decreasing the crosslinking of the macromolecular structure. The decreasing in crosslinking during the coalification process meaos thai there is depolimerization and aromatization reactions.
From the later and knowing that solvent extraction is higher for coals of 87% C, we can conclude that macromolecular structure for this rank of coal is of associative type. The low rank coals are most crosslinked but the aromatic cluster size is smaller. By free radical addition reaction and lost of methyl groups (methane production) the anthracite is obtained. The proposed structure explain the macroscopic properties of coal and helps to give new direction for research.
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