Quantitative Determination of Different Carbon Types in Fusinite and Anthracite Coals from Carbon-13 Nuclear Magnetic Resonance Chemical Shielding Line-Shape Analysis

¹³C NMR shielding tensors have been determined for two anthracite coals and a fusinite maceral by using powder pattern line shapes which have been analyzed as a superposition of three different bands due to benzenelike, condensed (bridgehead and inner) and substituted carbons. Theoretical calculations on circumcoroneneas a model compound support the Interpretations of the experimental data. Determination of the ratio of nonprotonated to protonated aromatic carbons obtained on the anthracites by the spectroscopic analysis Is in excellent agreement with the elemental analysis and previous studies by dipolar dephasing NMR techniques. The method therefore constitutes a valuable way to analyze the structure of high rank coals and should be useful in char characterization. The mole fraction of condensed carbons obtained by this technique is used to estimate the average cluster size in these polycondensed aromatic hydrocarbon materials. © 1988, American Chemical Society. All rights reserved.

Duke Scholars

Author Julio Cesar Facelli Biostatistics & Bioinformatics, Division of Translational Bi ...