Comparison of Seven West Virginia Coals with Their N-Methyl-2-pyrrolidinone-soluble Extracts and Residues. 1. Diffuse Reflectance Infrared Fourier Transform Spectroscopy

Seven West Virginia coals as well as their NMP-soluble extracts and residues have been examined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The nature of the OH bands in the raw coals is different from those in the extracts, where the OH groups exhibit weaker hydrogen bonding. It is also found that the extracts and the residues have the same aliphatic-to- aromatic ratio but more OH groups than their parent raw coals. This indicates that the total OH group content is increased in the extracts and residues after NMP extraction. The DRIFT spectra of heat-treated coal samples show that the pyrolysis products between 450 and 600° C are mainly aliphatic in character