One-dimensional description of the average polycyclic aromatic unit in Pocahontas No. 3 coal: an X-ray scattering study

Evaluation of coal‐related model compounds using tandem mass spectrometry

“…However, coal utilization remains of low efficiency and environmentally unfriendly due to the lack of knowledge of the composition of coals and coal derivatives . Much effort has been contributed to the investigation of the structure and composition of coals and their derivatives via various analytical techniques, including mass spectrometry (MS), Fourier transform infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, X‐ray diffraction, etc. Among the mentioned analytical methods, MS has proven to be a powerful tool in revealing composition information about unknown organic compounds in complex mixtures .…”

Conversión de Carbón a Productos Líquidos mediante Despolimerización Asistida por Solventes: una Revisión de los Fundamentos y Avances en la Región

“…Posee una intrincada estructura macromolecular tridimensional, conformada por bloques de unidades aromáticas policon-densadas 1,2 . Estos bloques policíclicos contienen heteroátomos como N, S y O, unidos entre sí por puentes metilénicos, uniones éter (R-O-R) y sulfuros o disulfuros (R-S-R y R-S-S-R).…”

“…Estos bloques policíclicos contienen heteroátomos como N, S y O, unidos entre sí por puentes metilénicos, uniones éter (R-O-R) y sulfuros o disulfuros (R-S-R y R-S-S-R). Ocasionalmente los puentes están conformados por cadenas alifáticas de longitud variable, lo que explica la presencia de carbonos alifáticos en la estructura policíclica macromolecular 2,3 . Dentro de este complejo entramado tridimensional se encuentran atrapadas algunas pequeñas moléculas (Figura 1).…”

X-ray scattering study of the average polycyclic aromatic unit in Ledo coal

“…Thus the studies indicate that the typical carbon content in coal is arranged in a macromolecular structure of condensed aromatic rings that form layer units, with bridges or 'cross-links' formed by aliphatic and/or other ethers conferring them a certain structural order (Chakrabortty & Kretschren, 1972Gonzalez et al, 2003). Studies of coal involving X-ray radial distribution function (RDF) analysis (Grigoriew, 1990;Wertz & Bissell, 1995;Wertz, 1998), the estimation of aryl and alkyl fractions in coal (Wertz, 1998;Wertz & Bissell, 1995;Heek, 2000), the average stacking height of the parallel aromatic layers in the c-axis direction, the average diameter of the parallel aromatic layers, the total numbers of stacking aromatic layers and the total number of carbon atoms present per aromatic layer etc. (Warren, 1941;Biscoe & Warren, 1942;Houska & Warren, 1954;Hirsch, 1954;Diamond, 1958;Lowry, 1963;Haenel, 1992;Van Krevelen, 1993;Iwashita & Inagaki, 1993;Heek, 2000;Takagi et al, 2004) have been carried out by many scientists.…”

“…(Warren, 1941;Biscoe & Warren, 1942;Houska & Warren, 1954;Hirsch, 1954;Diamond, 1958;Lowry, 1963;Haenel, 1992;Van Krevelen, 1993;Iwashita & Inagaki, 1993;Heek, 2000;Takagi et al, 2004) have been carried out by many scientists. X-ray scattering studies (Wertz & Bissell, 1995) of Argonne Premium Coal (APC501) indicate that the average carbon atom has approximately 2.5 nearest carbon neighbours separated by an average C-C distance of 1.41 Å . This is consistent with an alkyl/aryl distribution of 14/86%, in agreement with all of the various NMR studies.…”