Sodium amalgam reduction of humic acid—I. Evaluation of the method

Piper, Terry; Posner, A. M.

doi:10.1016/0038-0717(72)90067-3

Cited by 19 publications

(5 citation statements)

References 24 publications

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“…The bumic acid-type pigments were degraded by the NaamaIgam metbod (7,21,22,30,31). For tbis purpose 25-to 50-mg portions of the polymers were treated with 40 g of 3 % or 25 g of 5% Na-amaIgam under N 2 • Anthraquinones were specifically released by refluxing 50-mg portions under N 2 with 50 mI oí 1 % Na-ditbionite solution for 10 min.…”

Section: Methodsmentioning

confidence: 99%

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Anthraquinones and Phenols as Intermediates in the Formation of Dark‐Colored, Humic Acid‐Like Pigments by Eurotium echinulatum

Sáiz‐Jiménez¹,

Haider²,

Martin

1975

Soil Science Soc of Amer J

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EUrotiU711 echinulalum, a (ungus isolated (rom a vertisoJ in southcrn Spain, formcd humic acid-like pigments duriog growth in glucose-asparagine or gluoosc-NaNO;¡ media. After 6 to 7 days the phenols, orscllinic; ¡l·hydroxycinnamic, and p-hydroxyhcnzoic ncids, and the anthra<]uinones, cndocrocin, emodin, and physcion \Verc dctcctcd in the culture media. Upoo further dcvelopment of the mycclinJ mats additionaI aromatic compounds \Vere produccd and afte .. 4 to 6 wccks more than 50 different cther-extractahle phenoIs amI anthraquinoncs were detected. With further illcubation the nmounts and number oC these compounds dccreascd and pigment Cormation in the media increased. After 2 to 3 months the culture media were dark brown to black amI about 1 to 3.5 g/liter of polymer could be recovered upon acidification of the culture medium. Sodium amalgam rcduction of this polymer yielded numerous phcnols, anthraquinones, anthroncs, and possibly anthracene derivatives. Trcatment with sodium dithionite yieIded largely anthraquinones. The polymer contained 1 to 4.5% N depending upon the N source. From 50 to 60% of this N was released in the form of amino acids upon acid hydroIysis. With both asparagine and NaNO a as N sources the same amino acids were isoJated Crom ON Hel hydroIysates. Quantitatively, however, there were differences in the percentage distribution oC the amino acids. (24, 25. 26, 32). Jt is possibJe that the condensed hydrocarbons isolated either directly from the soil (5, 39) or upon zinc dust distilIation of humic acids (8.11, 13) mal' origina te by reduction of more highly condensed quinoid or phenolic structures. The fringelites of sea sediments discussed hy Blumer (4) and by Albrecht and Durisson (l) are dimeric anthraquinones with tetra-hydroxy-naphthodianthrone structures. They are derived from fossil crinoids and undergo a series of hydrations and dehydrations.For the present paper a study was made of anthraquinones -and phenols formed hy Eurotium echinulatum, a soil fungus isolated from a Vertizol in southern Spain. The linkage of these compounds into darkMcolored pigments similar to humic acid hy either phenolase or autoxidative polymerization proces.c;es in the culture medium and in the ceI1s during and after terminatíon of growth was followed. METHODSThe methods for cultivation and some properties of the darkcolored pigment have been described (22,23). The fungus was cultured in Czapek-Dox medium (20% glucose and 0.2% NaNO a ) or in glucose-asparagine medium (3% glucose and 0.5% asparagine) as described by Martin et al. (21). Growth and polymer formation was much better in the glucose~aspara gine medium. bu! the Czapek-Dox was preferred for monitoring the formation and transformation of phenols and anthraquinones. The phenols and anthraquinones were isolated from the culture media by acidification to pH 1.0 and extraction with peroxide-free ether. Concentrated cthcr extracts were spotted on thin layer silica gel (KGF 254. Fa, Merck, DarmstadO plates and chromatographed in two directions (9....

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Section: Methodsmentioning

confidence: 99%

“…It is possible that sorne fragmentation of the molecules takes place and much of the N not present as free amino groups or ammonia could be in the farOl of amino acid compounds linked to phenyl rings through the aOlino group. This linkage is resistant to 6N Hel hydrolysis (30,31).…”

Section: Mscussionmentioning

confidence: 99%

Anthraquinones and Phenols as Intermediates in the Formation of Dark‐Colored, Humic Acid‐Like Pigments by Eurotium echinulatum

Sáiz‐Jiménez¹,

Haider²,

Martin

1975

Soil Science Soc of Amer J

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“…W IC PIPER et at. (10), using model compounds, examined the types of bon s 10 Nathe reductant would break and confirmed that the diaryl ethers were cleaved by amalgam, while alkyl-aryl ethers were not.…”

Section: Co Rl1mentioning

confidence: 94%

“…ld be PIPER et at. (10) reported that up to 30% of the original humic aCid co u . II recovered in the form of phenolic materials under optimum conditions for reductiO , which was about 25 to 50 mg of humic acid per 30 g of 5% Na-amalgam.…”

Section: Co Rl1mentioning

confidence: 99%

Aromatic constituents of humic acids released by na-amalgam reductive cleavage, koh fusion and zinc dust fusion

Matsui

Kumada

1977

Soil Science and Plant Nutrition

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'l'he ~ight hurnic acids showing different degree of humification were treated with Hel (1:1). rus' ydro!yzed hurnic acids were subjected to reductive cleavage with Na-amalgam, KOH an~onaand zinc dust fusion. ThE' yields of dE' gradation products were determined by colorimetry g s chromatography. 'l'he ex. I perlmental rE'sults WE're summarized as follows: am l' The amounts of ether-soluble substances obtained by reductive cleavage with Na-Yiel: garn ranged from 21.6% for Kuragari (A type) to 7.8% for Kisokoma B. (Rp type). The 'Kuras Of. phenOlic SUbstancE'S exprE'ssed ill terms of vanillic acid content ranged from 3.0% for vanillf an ~A type) to 1.8% for Kisokoma 8 1 (Rp type). Resorcinol. p.hydroxybenzoic acid. the et: aCid, protocatE'chuic acid and syringic acid were detected in the gas chromatograms of (Rp t er-soluhle substances and their total yield comprised less than 0.6% of the Kisokoma F YPe).

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“…Later they extended the method to study several different soils with different origins and degrees of humification (39). First they investigated potential cleavage patterns and tried to optimize the method to enhance phenol production from soil humic acids (40).…”

Section: Alkali Metal Reduction Of Humic Materialsmentioning

confidence: 99%

Chemical Degradation of Humic Substances for Structural Characterization

Sonnenberg

Johnson

Christman

1988

Advances in Chemistry

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Chemical degradations of humic substances are reviewed, with emphasis on the identity of the products and how these compounds relate to the overall structure of the humic macromolecule. The methods described include (1) reduction using metals, hydrogen, and metal hydrides; (2) oxidation with copper oxide, permanganate, and chlorine; and (3) alkaline hydrolysis. Experimental results are reported for the reductive and solvolytic degradation of isolated aquatic humic acid using metallic sodium dissolved in liquid ammonia. A number of highly oxygenated compounds, many that commonly result from oxidative procedures, are identified in the reduction mixture. The presence of these structures in the original humic macromolecule is suggested. DEGRADATIVE TECHNIQUES CAN BE EFFECTIVE TOOLS for structural elucidation of complex natural polymers (I). Prediction of the types of bondsthat are unstable to a particular method of degradation, coupled with identification and quantification of products, can indicate what substructures are included in the macromolecule and how they are linked together. Ideally, these techniques will produce untransformed subunits in a mechanistically predictable manner.Degradative methods have long been used to examine the subunits that exist in humic substances and their mode of attachment to the parent molecule. Aquatic humic material has been degraded hydrolytically and oxidatively by a variety of methods. However, because of the uncertainty about

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Sodium amalgam reduction of humic acid—I. Evaluation of the method

Cited by 19 publications

References 24 publications

Anthraquinones and Phenols as Intermediates in the Formation of Dark‐Colored, Humic Acid‐Like Pigments by Eurotium echinulatum

Anthraquinones and Phenols as Intermediates in the Formation of Dark‐Colored, Humic Acid‐Like Pigments by Eurotium echinulatum

Aromatic constituents of humic acids released by na-amalgam reductive cleavage, koh fusion and zinc dust fusion

Chemical Degradation of Humic Substances for Structural Characterization

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