| | 1 | Author
| Shinji Ohmori, Kazuko Takahashi, Mikiko Ikeda, Toshihiko Ubuka | Requires cookie* | | | Title
| A Fundamental Study of Quantitative Desulfurization of Sulfur Containing Amino Acids by Raney Nickel and its Character  | | | | Abstract
| The desulfurization of several naturally oc cm-ring sulfur-containing amino acids by Raney nickel was studied under various conditions. Raney nickel, which was prepared by treating Al-Ni alloy with 5 N NaOH at 60 °C for 30 min, and was not washed with water, was most active and desulfurized, in quantitative yield, methionine, homocysteine, homocystine, homocysteine sulfinic acid, S-(2-carboxy-n-propyl)-L-cysteine, cysteine, cystine, cysteine sulfinic acid and S-methylcysteine sulfoxide. Raney nickel prepared from 100 mg of Al-Ni alloy desulfurized quantitatively up to 40 //mol methionine at 60 °C for 30 min. The desulfurization occurred effectively in the pH range of 7 and 13, but not below 7. Methionine sulfone, cysteic acid, and homocysteic acid were not subject to the reaction. The Raney nickel was deactivated by H2S, and H2O2, or combustion. De-sulfurization activity was not enhanced by hydrogen gas. | | | |
Reference
| Z. Naturforsch. 36b, 370—374 (1981); received November 27 1980 | | | |
Published
| 1981 | | | |
Keywords
| Desulfurization, Raney Nickel, Sulfur Containing Amino Acids | | | |
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| | | | | TEI-XML for
| default:Reihe_B/36/ZNB-1981-36b-0370.pdf | | | | Identifier
| ZNB-1981-36b-0370 | | | | Volume
| 36 | |
| 2 | Author
| Leopold Horner, Christoph Franz | Requires cookie* | | | Title
| Studien zum Vorgang der Wasserstoffübertragung, 75 [1] Elektrochemische Untersuchungen von S-und P-vergiftetem Raney-Nickel (Ra—Ni) und Versuche zu dessen Reaktivierung Studies on the Occurrence of Hydrogen Transfer, 75 [1] Electrochemical Investigation of Raney-Nickel (Ra—Ni) Poisoned with S and P and Experiments for the Reactivation | | | | Abstract
| Ra—Ni with an artificial rest potential of —1000 mV (vs SCE) is shifted with different rates to more positive values after the addition of thioethers and carbon disulfide. Only with Na 2 S-9H 2 0 a potential of —1100 mV (constant) is observed. Ra—Ni poisoned with sulfur is not reactivated neither cathodically nor anodically nor by the corrosive degradation at constant pH. Hydrogen structurally incorporated into the lattice of Ra—Ni (structural bonded hydrogen) is consumed by poisoning with thioethers and trivalent phosphorus compounds in a stoichiometric way. Ra—Ni-powder stepwise corrosively degradated up to 30% shows the same degree of desulfuri-zation as the original Ra—Ni. Desactivated Ra—Ni (loss of structural bonded hydrogen) is reacti-vated (56%) by cathodical treatment. In competing reactions the P—S, C—S, and C —P-bond in thiophosphinic esters, thioethers and trivalent P-compounds are hydrogenolyzed by Ra—Ni, the C—P-bond faster than the C—S-bond. | | | |
Reference
| Z. Naturforsch. 40b, 814—821 (1985); eingegangen am 31. Januar 1985 | | | |
Published
| 1985 | | | |
Keywords
| Structural Bonded Hydrogen, Hydrogen Transfer, Raney-Nickel, Electrochemical Investigation | | | |
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| default:Reihe_B/40/ZNB-1985-40b-0814.pdf | | | | Identifier
| ZNB-1985-40b-0814 | | | | Volume
| 40 | |
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