Results 271 to 280 of about 64,537 (313)
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Tetrahedron, 1968
Abstract The effect of KOH fusion, pyrolysis, and hydriodic acid on acid boiled humic acid (ABHA) has been studied. As many of the products of the KOH fusion of ABHA are obtained similarly from the “polymers” of o - or p -benzoquinone or furfural, it is probable that the fusion products shed little, if any, light on the constitution of HA.
M.V. Cheshire +2 more
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Abstract The effect of KOH fusion, pyrolysis, and hydriodic acid on acid boiled humic acid (ABHA) has been studied. As many of the products of the KOH fusion of ABHA are obtained similarly from the “polymers” of o - or p -benzoquinone or furfural, it is probable that the fusion products shed little, if any, light on the constitution of HA.
M.V. Cheshire +2 more
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Chemiluminescence of Humic Acids
Nature, 1967THE concept that humic acids (HA) are heteropolycondensates of phenolic substances is now widely accepted1,2. All the humic acids have hydroxyl, methoxy, or carbonyl groups connected with the aromatic parts of the nucleus. Our earlier investigations suggested that oxidation of hydroxyl groups attached to the aromatic ring may be accompanied by ...
DANUTA SŁAWIŃSKA, JANUSZ SŁAWIŃSKI
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Tetrahedron, 1971
Abstract The synthesis is described of quinones containing α-amino acid ester substituents and the structure of the products is established by NMR and mass spectroscopic techniques. Hydrolysis of the products with 6N HCl has been studied; the products behave as vinylogous amides but the release of nitrogen in the form of amino acid is low ...
P.A. Cranwell, R.D. Haworth
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Abstract The synthesis is described of quinones containing α-amino acid ester substituents and the structure of the products is established by NMR and mass spectroscopic techniques. Hydrolysis of the products with 6N HCl has been studied; the products behave as vinylogous amides but the release of nitrogen in the form of amino acid is low ...
P.A. Cranwell, R.D. Haworth
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2005
Humic acids are iodinated by elemental iodine and, if the iodine is present as iodide, by peroxidase-mediated reactions. It is demonstrated that iodination of humic acids leads to a product with a uniform distribution of iodine. It could not be unambiguously verified whether the enzymatically mediated iodination is a direct reaction between a ...
Jesper V. Christiansen, Lars Carlsen
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Humic acids are iodinated by elemental iodine and, if the iodine is present as iodide, by peroxidase-mediated reactions. It is demonstrated that iodination of humic acids leads to a product with a uniform distribution of iodine. It could not be unambiguously verified whether the enzymatically mediated iodination is a direct reaction between a ...
Jesper V. Christiansen, Lars Carlsen
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Tetrahedron, 1967
Abstract The action of water and acids on “humic acid” (HA) is described, and it is concluded that HA is a complex of a polycyclic aromatic “core” responsible for the ESR spectrum which is attached to polysaccharides, proteins, relatively simple phenols and metals.
M.V. Cheshire +4 more
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Abstract The action of water and acids on “humic acid” (HA) is described, and it is concluded that HA is a complex of a polycyclic aromatic “core” responsible for the ESR spectrum which is attached to polysaccharides, proteins, relatively simple phenols and metals.
M.V. Cheshire +4 more
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Solid Fuel Chemistry, 2015
A method for the chemical modification of humic acids with benzoyl chloride under the conditions of phase-transfer catalysis was developed. It was demonstrated by potentiometric titration that the reaction of humic acids with benzoyl chloride can occur at both hydroxyl (–OH) and carboxyl (–COOH) groups.
S. L. Khil’ko +5 more
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A method for the chemical modification of humic acids with benzoyl chloride under the conditions of phase-transfer catalysis was developed. It was demonstrated by potentiometric titration that the reaction of humic acids with benzoyl chloride can occur at both hydroxyl (–OH) and carboxyl (–COOH) groups.
S. L. Khil’ko +5 more
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Plant and Soil, 1972
An explanation has been advanced for the previously reported observation that alkaline hydrolysis of humic acids will release amino acids that are resistant to acid hydrolysis. It is thought that under the alkaline conditions oxidation of N-phenyl-amino acids to the more readily hydrolysed quinonimines occurs.
T. J. Piper, A. M. Posner
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An explanation has been advanced for the previously reported observation that alkaline hydrolysis of humic acids will release amino acids that are resistant to acid hydrolysis. It is thought that under the alkaline conditions oxidation of N-phenyl-amino acids to the more readily hydrolysed quinonimines occurs.
T. J. Piper, A. M. Posner
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The Chemistry of Fungal Humic Acid‐like Polymers and of Soil Humic Acids
Soil Science Society of America Journal, 1973Abstract A. niger, E. nigrum , and S. chartarum were grown in glucoseasparagine media according to Martin et al. The fungal “humic acids” synthesized were isolated, purified, and characterized by elementary and functional group analyses and by ...
M. Schnitzer +2 more
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Prospects for humic acids treatment and recovery in wastewater: A review
Chemosphere, 2023Jiadong Liu +2 more
exaly
A Study on the Adsorption Isotherms of Humic Acid and Modified Humic Acids
International Journal of Scientific and Research Publications (IJSRP), 2019Lin Lin Tun, Than Than Aye
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