/sup 29/Si NMR: A new tool for coal liquids characterization
Protonated heteroatom functionalities (COOH, OH, Sh, NH) have a major impact on the chemical and physical properties of coal materials. Characterization of these functionalities will, therefore, be important to efficient development of new coal utilization technologies. Silicon-29 NMR spectroscopy of the trimethysilyl derivatives of these functional groups is a powerful new tool for this characterization. Preparation of the trimethylsilyl derivatives is carried out in the NMR sample tube and the /sup 29/Si NMR spectrum of the products is accumulated under conditions similar to those routinely used in /sup 13/NMR. Studies on derivatized model compounds show that /sup 29/Si chemical shifts are generally segraged into three regions characteristic of COOh, OH and SH, and NH functionalities. The /sup 29/Si resonances of aromatic OH derivatives are further differentiated so that the major oxygenated components of coal liquids can be monitored as a function of processing and distillation conditions. Quantitative /sup 29/Si NMR results are used to calculate total OH and COOH concentrations in several solutions. Comparison of these results with the elemental oxygen content permits an estimated of the percentage oxygen present in non-derivatizable (e.g., ether) groups. The technique is illustrated using soluble coal liquid distillate fractions boiling in the range of initial boiling point to 1050/sup 0/F (566 /sup 0/C).
- Research Organization:
- Analytical and Information Division; Corporate Research Laboratories-Fuels Science Exon Research and Engineering Company, Linden, New Jersey 07036
- OSTI ID:
- 6356308
- Report Number(s):
- CONF-8006116-
- Journal Information:
- AIP Conf. Proc.; (United States), Journal Name: AIP Conf. Proc.; (United States) Vol. 70:1; ISSN APCPC
- Country of Publication:
- United States
- Language:
- English
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