Determination of nonprotonated aromatic carbon concentrations in coals by single pulse excitation carbon-13 NMR

Autor:	C. E. Snape, Robert V. Law, G. D. Love
Rok vydání:	1993
Předmět:	Chemistry business.industry General Chemical Engineering Anthracite Analytical chemistry Energy Engineering and Power Technology Mineralogy chemistry.chemical_element Aromaticity Carbon-13 NMR Fuel Technology Coal Fourier transform infrared spectroscopy Vitrinite business Carbon Excitation
Zdroj:	Energy & Fuels. 7:639-644
ISSN:	1520-5029 0887-0624
DOI:	10.1021/ef00041a012
Popis:	It is now generally accepted that single pulse excitation (SPE) or Bloch decay measurements are essential for obtaining reliable aromaticity values for coals by solid-state 13 C NMR although such measurements are considerably more time consuming than cross-polarization (CP). Just as with normal CP, SPE can be combined with dipolar dephasing (DD) to derive nonprotonated aromatic carbon concentrations. This approach has been applied to four of the Argonne premium coal samples (APCS, N. Dakota lignite, Wyodak, Illinois no. 6, and Pocahontas), two vitrinite concentrates from UK bituminous coals, and an anthracite. The results have been compared with those obtained from CP and, for the APCS, nonprotonated aromatic carbon concentrations derived indirectly from FTIR and 1 H CRAMPS
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::63e2d92a1978d07832595b8f3cac48b4 https://doi.org/10.1021/ef00041a012 Zobrazit plný text záznamu