Molecular compounds generated by ruthenium tetroxide oxidation and preparative off line thermochemolysis of lignite humic acids from South Moravia: Implications for molecular structure

Recent applications in analytical thermochemolysis

“…The use of TMAH combined alternatively with less basic reagents has been popular to discriminate free vs. bound fatty acids. As an example, the use of tetraethylammonium acetate (TEAAc) to derivatize free fatty acids only and TMAH to react with and derivatize both free and bound fatty acids showed that fatty acids in humic acid sample were mostly in their free forms, trapped within the organic network [9][10]. Another advantage of the use of TEAAc is to differentiate experimentally added ethyl groups from originally present methyl groups.…”

“…The combination of thermochemolysis-TMAH and thermochemolysis-TEAAc revealed that most of the fatty acids associated in humic acid fractions isolated from lignite deposit samples were in the free form [9]. Thermochemolysis in the presence of a weak base reagent, TEAAc, also indicated that n-alkanes and some fatty acids were bonded in a humic acid structural network by weak bonds.…”

Organic Geochemistry of Humic Acids From a Neogene Lignite Sample, Bulgaria

“…Acids and neutrals were separated from the bitumen-"free" fraction on a SiO 2 /KOH column (McCarthy and Duthie, 1962). Hydrocarbons, ketones and esters were separated from the other neutrals applying liquid chromatography and using for elution diethyl ether/petroleumether mixtures of increasing polarity (Grasset and Amblès, 1998;Válkova et al, 2009). Acids were identified as methyl esters.…”

“…Their forms of linkage have been studied by several researchers in a suite of papers devoted to humic acids in soils, peat, lignite, etc. (Amblès, 2001;Grasset et al, 2002;Guignard et al, 2005;Deport et al, 2006;Válkova et al, 2009). Except "free" fatty acids extraction, authors used thermochemolysis in the presence of different alkylation reagents, i.e.…”

Molecular changes in particulate organic matter (POM) in a typical Chinese paddy soil under different long‐term fertilizer treatments

“…In contrast, the relative abundance of long chain (C 20 –C 30 ) FAMEs (Figure 4) was only 4–6.4% and it accounted for approximately 14–29.5% of total linear FAMEs. Generally, short‐chain FAMEs have been found to have multiple origin (Amblès et al , 1994; Marseille et al , 1999), while long‐chain FAMEs were usually derived from biopolymers such as waxes or suberin from higher plants that underwent de‐polymerization (Kolattukudy, 1980; Guignard et al , 2005; Válková et al , 2009).…”