Characterization of humic acids from low-rank coals by 13C-NMR and pyrolysis-methylation. Formation of benzenecarboxylic acid moieties during the coalification process

摘要

Instituto de Recursos Naturales y Agrobiologia de Sevilla, C.S.I.C., P.O. Box 1052, 41080-Seville, Spain; E-mail address: delrio@irnase.csic.es