A COMPARISON OF DRIFT AND KBR PELLET METHODOLOGIES FOR THE QUANTITATIVE-ANALYSIS OF FUNCTIONAL-GROUPS IN COAL BY INFRARED-SPECTROSCOPY

A set of pyridine soluble coal extracts, previously characterized by F ourier transform infrared spectroscopy using the KBr pellet technique, are now characterized using diffuse reflectance. The ratios of the ar omatic to aliphatic CH band areas are plotted against the ratio's of t he aromatic to aliphatic CH contents determined by proton NMR, thus al lowing the determination of the ratio of average absorption coefficien ts. This quantity varies with coal origin but also differs from that o btained using KBr pellets. This latter procedure produces superior cor relations and is to be preferred for accurate quantitative work.