Results 251 to 260 of about 17,547,833 (304)

Anoxic dissolution of troilite in acidic media

Journal of Colloid and Interface Science, 2006
The anoxic dissolution of troilite (FeS) in acidic medium has been investigated at 50 degrees C using batch dissolution experiments. Two different progress variables were followed during solid dissolution, i.e., the amounts of dissolved iron (nFe) and formed hydrogen sulfide (n(H(2)S)). The experimental studies performed at hydrogen ion concentrations (
Chirita, P., Descostes, M.
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Epimerization of Benzylpenicilloic Acid in Alkaline Media

Journal of Pharmaceutical Sciences, 1984
5R,6R-Benzylpenicilloic acid was found to epimerize slowly in alkaline media to 5S,6R-benzylpenicilloic acid until equilibrium was established. Epimerization proceeded via the imine tautomer of penamaldic acid rather than the enamine form and was found to favor the 5S,6R-epimer at equilibrium.
I, Ghebre-Sellassie, S L, Hem, A M, Knevel   +2 more
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Reactions of ketones with aromatics in acid media. The effect of trifluoromethyl groups and the acidity media. A theoretical study

Journal of Molecular Modeling, 2012
The reactions of acetone, 2,2,2-trifluoroacetone and hexafluoroacetone in methanesulfonic (MSA) and triflic acids (TFSA) with benzene have been studied at M06-2X/6-311+G(d,p) level using cluster-continuum model, where the carbonyl group is explicitly solvated by acid molecules.
Ulises Jiménez, Castillo, Mikhail G, Zolotukhin, Lioudmila, Fomina, Daniel Romero, Nieto, Lilian Olivera, Garza, Serguei, Fomine   +5 more
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Improved Activity in Acidic Media of Immobilized Lysozyme

Applied Biochemistry and Biotechnology, 1999
Polyethylene glycols (PEGs) of various chain length were used to crosslink lysozyme onto an insoluble support such as oxirane. A very high degree of modification and no inactivation of lysozyme were obtained with PEG 20000, but enzymatic activity increased up to 20 times at pH 3.0, at which point the activity of the native enzyme was lower when using ...
ZACCHIGNA, MARINA, DI LUCA GABRIELLA, LASSIANI, LUCIA, VARNAVAS ANTONIOS, PITOTTI ANNA, BOCCÙ ENRICO   +5 more
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Pyrite dissolution in acidic media

Geochimica et Cosmochimica Acta, 2004
Oxidation of pyrite in aqueous solutions in contact with air (oxygen 20%) was studied at 25°C using short-term batch experiments. Fe2+ and SO42− were the only dissolved Fe and S species detected in these solutions. After a short period, R = [S]tot/[Fe]tot stabilized from 1.25 at pH = 1.5 to 1.6 at pH = 3. These R values were found to be consistent with
Descostes, M., Vitorge, P., Beaucaire, C.   +2 more
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Pentafluorophenyliminothiodihalides and their conversions in acid media

Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1979
1. Pentafluorophenyliminothiodifluoride is formed upon the action of SF4 on pentafluoroaniline in the presence of NaF. A new group of unsymmetrical thiodiimides, containing the pentafluorophenyl ring, is synthesized. 2.
A. V. Zibarev, I. R. Gol'ding, A. M. Sladkov, G. G. Furin, G. G. Yakobson   +4 more
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Pyrrhotite dissolution in acidic media

Applied Geochemistry, 2014
Abstract Non-oxidative dissolution rates for hexagonal pyrrhotite (Fe1−xS) were measured for pH values ranging from 0 to 1.3 and temperatures ranging from 25 to 70 °C. These results showed that pyrrhotite dissolution rate increases with decreasing pH or increasing temperature.
Paul Chiriţă, J. Donald Rimstidt
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Chemistry of sulphenates in acidic media

Journal of the Chemical Society, Perkin Transactions 2, 1978
Methyl toluene-p-sulphenate is hydrolysed rapidly in moist solvents (dioxan, benzene, chloroform, or nitrobenzene) yielding methyl toluene-p-sulphinate, di-p-tolyl disulphide, and methanol. The reaction is acid catalysed. At higher concentration of water (>1%) the products are: p-tolyl toluene-p-thiolsulphonate, di-p-tolyl disulphide, and methanol.
Ennio Ciuffarin, Sandro Gambarotta, Mauro Isola, Lucio Senatore   +3 more
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Reactions of Mixed Natural Acids and Esters in Acidic Media

2023
Citric acid and malic acid are renewable organic acids with considerable market size. The reaction between the two acids in sulfuric acid at 80 °C gave an unexpected pyrone diacid. A mixture of dimethyl malate and trimethyl citrate gave a pyrone diester. These pyrones were produced in good yields on a multigram scale.
William J. Bradley, Yang Qu, Zachery Crandall, Theresa L. Windus, George A. Kraus   +4 more
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T. C. in acidic media

Journal of Labelled Compounds, 1970
AbstractTritium labelling of aromatic compounds in a few acidic media and the intramolecular distributions of radioactivities in the tritiated compounds were investigated. Various kinds of aromatic compounds were treated with powerful acid complex, TH2PO4.BF3, or some other tritiated acids at room temperature.
Masayuki Hamada, Reiko Kiritani
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