Examination and comparision of structure: lignite, bituminous and anthracite coal. [10 references]

Coal can be described as an amorphous mixture of macromolecules each made up of a complex array of organic molecules chemically linked together. Methods for breaking up these macromolecules in order to characterize the aromatic structural types have been explored. Pyrolysis is a common method for depolymerizing coal, but under the conditions necessary for pyrolysis much structural rearrangement occurs making a comparison of the products to the initial structural groups in coal difficult if not impossible. One approach has been to use a variety of selective oxidation methods. Aqueous sodium dichromate, aqueous air oxidation with uv light, and hydrogen peroxide in acetic acid have been used. Initial results of some of these studies have been published. This work has been extended to include characterization and comparison of a lignite, bituminous coal, and anthracite. Besides the oxidation products, the monomeric organic molecules trapped within the macromolecules are examined and the results interpreted in relation to coal structure and the coalification process.