Investigation of the formation of humic acids from lignite by using model compounds

By using model compounds, the formation of humic acids from lignite was investigated. Quinones (p-benzoquinone, o-benzoquinone, p-toluquinone, 1,4-nafto-quinone, 9,10-anthraquinone, 9,10-phenanthraquinone), polyhydroxyaromatic compounds (1,2-dihydroxybenzene, 1,4-dihydroxybenzene), and hydroquinone-formalde-hyde resins were used as model compounds. Humic acids were obtained from all of the model compounds used except 9,10-anthraquinone. It was suggested that the formation mechanism of humic acids from lignite was similar to quinone-humic acids. © 1991 Taylor and Francis Group, LLC.