Constitution of Illinois No. 6 Argonne Premium Coal: A Review

A review of the chemical and physical structural features of the Argonne Premium Illinois No. 6 coal is presented. The topics covered include aromatic and aliphatic components, functional groups and heteroatoms, molecular weight distribution, nature of the cross-linked network, porosity, surface area, and density. (13)C NMR indicated that Illinois No. 6 high-volatile bituminous coal contains 15 aromatic carbons (three to four fused aromatic rings) and 5 attachments per cluster, and an average cluster molecular weight of 316 Da. Methyl units are the most abundant pendant alkyl groups. XPS data showed that organic oxygen, nitrogen, and sulfur functionalities are primarily ether and phenolic, pyrrolic, and thiophenic groups, respectively. Solvent swelling studies suggested that Illinois coal structure is composed of a covalently bonded network of aromatic clusters that are extensively hydrogen bonded. SANS analyses showed that Illinois coal is mostly microporous and (129)Xe NMR indicated that the pore structure of Illinois coal consisted of two distinct regions with average pore diameter of 6 and 10 angstrom.