Coal Structure
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Advances in Chemistry Series No. 192 Martin L. Gorbaty, Editor Exxon Research and Engineering Company
Figure 4. Mass spectra, taken at the tops of GC peaks in a GC/MS analysis of an organic extract from an Ontario incinerator fly ash, show well-defined spectra with intense molecular ions for each isomeric group of dioxins
K. Ouchi, Editor Hokkaido University Based on a symposium sponsored by the Division of Fuel Chemistry of the Ameri can Chemical Society. An excellent treatment of research on this important source of electricity and synthetic fuel. This 22-chapter volume focuses on the organic, inorganic, and physical structure of coal. Following an introductory over view of coal science, the advances in ap plying new spectroscopic techniques to gain a better understanding of coal struc ture are examined. This book will be of continuing interest and use to all coal and analytical chemists who are presently conducting research on coal structure. CONTENTS Coal Structure and Coal Science · Average Aromatic Ring Size · Labeled Guest Molecules in Coal · Nature of the Free Radicals in C o a l s · Ή NMR Absorption in Coal and Pitch «Applica tion of " C . 2 H . ι Η NMR and GPC to the Study of Structural Evolution of Subbituminous Coal · Coal Structure and Thermal Decomposition Products · Carboxylic Acids and Coal Structure • Lignin-Like Polymers in Coals · Short-Time Reaction Products of Coal Liquefaction · Characterization of Hydrolytically Solubilized Coal · Chemistry of Acid-Catalyzed Coal Depolymerization · Structure of Brown Coal by Reaction with Phenol · Alkylation of Coal · Re ductive Alkylation of Coal · Organic Sulfur Functional Groups · Chemical Structure of Heavy Oils Derived from Coal Hydrogénation · Reagent Access and the Reactivity of Coals · Sorption Studies · Particulate Structure in Alkali-Treated Brown Coal · Ultrafine Structure of Coal · Iron-Bearing Minerals in Coal 376 pages (1981) LC 80-24104
Clothbound $36.00 ISBN 0-8412-0524-8
Order from: SIS Dept. 63 American Chemical Society 1155 Sixteenth Street, N.W. Washington, D C 20036 or CALL TOLL FREE 800-424-6747 and use your credit card.
Figure 5. Data from a GC/MS analysis of fly ash extract show the reconstructed chromatogram and mass chromatograms for each group of dioxins. Using characteristic molecular ions for each isomeric group, some individual isomers and their associated GC peaks are clearly seen in this complex mixture. These data were obtained using a packed column and temperature-programmed run each isomeric group can be done using reference standards and mass chromatograms. However, the selected-ion monitoring (SIM) mode of GC/MS operation gives higher sensitivity and a broader range of applicability (see Figure 1), since the mass spectrometer only detects a few selected ions rather than scanning an entire spectrum. It is necessary for SIM data to confirm that the peaks represent the dioxins, and not similar compounds that just happen to have the same retention times. We obtain a confirmation from
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data in Figure 6, which show ions characteristic of the TCDD. This figure also shows that corresponding peaks in the different traces have the same intensity ratios as are observed in mass spectra of TCDD. The WCOT column produces 14 defined GC peaks instead of the seven obtained on a packed column (Figure 5). One can analyze the extract of these samples for dioxins without prior cleanup because the dioxins are at relatively high concentrations and interfering compounds are either not present or are at
