Lignin humic acids

Oxidation with alkaline CuO gave large amounts of meta-hydroxy derivatives of benzoic acid and benzene dicarboxylic acids (Hayatsu et al., 1980a). This suggests the presence of phenol ethers in the polymer structure. Interestingly, terrestrial polymers such as lignin, humic acid, and coal yield mainly para-rather than meta-hydroxy derivatives by this method. 

Although trihydroxybenzenes and their derivatives have been isolated from the oxidation products of lignins, humic acids, and land-derived marine sediments (5, 17, 23, 24, 27), it was found that 2,6-dimethoxy-... 

The traditional bleaching of paper with chlorine leads to an effluent containing 45-90 kg of organic waste per ton of pulp, of which 4-5 kg is organically bound chlorine.76 These include various chlorinated furanones, cyclopen-tenediones, and other materials.77 These are derived from lignin, humic acids, and such. Typical compounds are structures 3.8 and 3.9. 

Further proof of the reactivity of nitrous acid with organic matter has been supplied by the work of Stevenson and Swaby (1964). By means of manometric and infrared methods they showed that nitrous acid can react with lignin, humic acid, fulvic acid and polyphenols. The gases produced included nitrogen, nitrous oxide and methyl nitrite, formed when nitrous acid reacted with lignin and phenolic derivatives. The percentage of the nitrous acid that was fixed by these substances was not reported. 

The erosion resistance of soil can be improved by increasing the autohesion of the soil aggregates this may be done by treating the soil with binder materials. Substances that may be used for this purpose include cellulose and its derivatives (lignin, humic acid), asphalt or other bitumens, peat gum, and various structure-forming substances from plant residues. The adhesive material coats the soil particles. The layer that is formed, with a thickness of a few microns, makes the soil particles tacky and hence increases the interaction among the particles. 

Phenolic acids in soils range from simple compounds such as benzoic acid derivatives to complex polymers such as tannins (Figs. 3.4 and 3.5). There is also a large array of polymers that contain phenolic acid moieties (e.g., lignin, humic acids. 

Organophilic polyphenolic materials for oil-based drilling fluids have been described [407], The additives are prepared from a polyphenolic material and one or more phosphatides. The phosphatides are phosphoglycerides obtained from vegetable oils, preferably commercial lecithin. Humic acids, ligno-sulfonic acid, lignins, phenolic condensates, tannins the oxidized, sulfonated, or sulfomethylated derivatives of these polyphenolic materials may serve as polyphenolic materials. 

Polyphenolic materials prepared from a polyphenolic material (humic acids, lignosulfonic acid, lignins, phenolic condensates, tannins) and phosphatides (lecithin) - [407]... 

Since lignins are polymers of phenolics and are major plant constituents with resistance to microbial decomposition, they are the primary source of phenolic units for humic acid synthesis (178, 179). Once transformed, these humic acids become further resistant to microbial attack and can become bound to soils (180) form interactions with other high molecular weight phenolic compounds (ex. lignins, fulvic acids) and with clays (181) and influence the biodegradation of other organic substrates in soils (182, 183). 

Sapsucker Woods humic acid, Sapsucker Woods fulvic acid, tannic acid, lignin, zein, cellulose, Aldrich humic acid, headspace equilibrium, Garbarnini Lion 1986)... 

Many of the methods used for lignins can also be applied to humic acids. Thus the use of pulse polarography after the formation of nitroso derivatives is possible with humic acids as well as lignins [433,443]. If the fulvic acids are... 

Lindberg, W., Persson, J. A., Wold, S. Anal. Chem. 55, 1983, 643-648. Partial least-squares method for spectrofluorimetric analysis of mixtures of humic acid and lignin-sulfonate. 

In some scrub and strip circuits, the crud is mainly composed of silica, as well as inorganic sulfates. Also, if poor pH control is used in the uranium stripping circuits with ammonium sulfate, then uranium is a major constituent [33,46]. Such crud may be treated with dilute sulfuric acid, and recirculation through a pump results in the crud breaking down. There is evidence, in at least a few uranium circuits, that the presence of humic acids may be a possible cause of the crud problem [34,47]. Lignin appears to be another cause of crud formation [33,46]. Humic acids contained in the feed solution have also been implicated in the formation of waxy cruds in plants extracting uranium from phosphoric acid. 

Presence of humic acids, lignin Solvent extraction ... 

Both and nmR showed the presence of aromatic and aliphatic components. In l C-NMR, resonances at =58 ppm indicate the presence of many OCH3 groups, such as those occurring in syringic, vanillic, and ferulic acids. Spectra clearly show the presence of palmitic and stearic acids by GC/MS, IR, and NMR data. The fulvic and humic acids are predominantly made up of phenolic and fatty acid units. These are highly aromatic because lignin residues have been incorporated in the humification process. 

Fig. 19 a and b. Spectra for the spectrofluorimetric analysis of a mixture of humic acid and lignin-... 

The results of elementary analyses of lignin isolated from fresh (2, 3) and rotted straw and data for different types of coals and humic acids isolated from these and from chernozem are shown in Table III to illustrate further steps of coalification. The following points should be noted ... 

B. K. Mazumdar. Low rank coals like lignites and natural humic acid derived from such coals are known to contain alicyclic structures in their constitution. How does the author envisage the formation of such structures in the transformation of lignin to humic acid-like substances ... 

Vauquelin (14), A. Klaproth (6), and R. Jameson (5), alkali soluble organic constituents of soil and coal are designated as humic acids/ Collectively, these substances make up an ill-defined series of dark colored, weakly acidic solids which form whenever plant components (such as lignin) are exposed to fungal oxidases, or when coal is allowed to weather or otherwise oxidize. Some evidence now exists that humic acids isolated from these varied sources do indeed contain several common peripheral structures (2, II, 16), but by any more discriminating test, the term possesses little chemical significance or fixed meaning. 

Figure 1.2. Differential thermal analysis for the humic acid fraction isolated in NaOH from a sapric histosol (1), from the acid precipitate isolated from products of the reaction of meth-ylglyoxal with glycine (2), and from the acid precipitate formed from the reaction of glucose with glycine (3), alkali lignin (4), casein (5), lignin-casein 3 1 complex (6), and lignin-casein 6 1 complex (7).

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