Results 141 to 150 of about 370 (171)
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Vanadyl porphyrins in crude oil and vacuum gasoil
Chemistry and Technology of Fuels and Oils, 1986The authors have segregated vanadyl porphyrins from mixed West Siberian crudes and from the corresponding gasoil (350-500/sup 0/C) by a combined extraction-chromatographic method in order to establish their composition. The vanadyl porphyrin concentrations were determined spectrophotometrically according to the intensities of the absorption band at 570
N. I. Shilonosova +2 more
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Electron Spin Resonance of Some Vanadyl Porphyrins
The Journal of Chemical Physics, 1961The electron spin resonance spectra of the vanadyl complexes of etioporphyrin II, vanadyl mesoporphyrin IX dimethyl ester, and deuteroporphyrin IX dimethyl ester have been studied and found to be identical to within experimental error. Unlike the corresponding copper complexes, the vanadyl complexes give no observable nitrogen hyperfine effects.
E. M. Roberts +2 more
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Spectrophotometry and solubility properties of nickel and vanadyl porphyrin complexes
Energy & Fuels, 1990Spectrophotometric standards of purified synthetic Ni II and V IV complexes with etioporphyrin-I and octaethylporphyrin structures have been evaluated. Extinction coefficients, and their solvent dependence, were measured with a diode array spectrophotometer. Metalloporphyrin absorption bands (ca. 550 nm for the Ni II and ca.
David H. Freeman +2 more
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ChemInform Abstract: WIRKUNG VON VANADYL‐OCTAAETHYL‐PORPHYRIN
Chemischer Informationsdienst. Organische Chemie, 1970AbstractAus der betreffenden Base erhält man mit Vanadylsulfat in Eisessig das Vanadyl‐octaäthyl‐porhyrin (Ia), dessen Demetallisierung untersucht wurde.
R. BONNETT, P. BREWER
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High-performance liquid chromatography of vanadyl porphyrins
Analytical Chemistry, 1985A rapid, highly reproducible high-performance liquid chromatographic method is described for the analysis of vanadyl porphyrins from fossil fuels. The ability to separate structural as well as positional isomers is also demonstrated. This method eliminates the problems and ambiguities associated with the demetalation of porphyrin mixtures which is ...
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Obtaining vanadyl porphyrins from asphaltite of sadkinsk deposit
Chemistry and Technology of Fuels and Oils, 1987A method of obtaining vanadyl porphyrins by acetone treatment of asphaltite was proposed. A 1 gram asphaltite sample and 200 ml of acetone were placed in a flask and refluxed by 1 hour. After cooling, the solution was filtered and the content of vanadyl porphyrins in the acetone extract was determined by a spectrophotometer. The product was obtained in
N. K. Nadirov +4 more
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Catalytic epoxidation of olefins in the presence of a vanadyl porphyrin complex
Petroleum Chemistry, 2006It was found that vanadyl porphyrin complexes synthesized from petroleum metal porphyrin concentrates stimulated epoxidation during the olefin oxygenation process. The yields of obtained oxiranes turned out to be 38–75%, depending on the olefin structure.
G. F. Miralamov, Ch. I. Mamedov
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Structural features of vanadyl porphyrins of petroleum of West Kazakhstan
Petroleum Chemistry U.S.S.R., 1984Abstract 1. 1. Homologous of two main series: alkylporphyrins and monocycloalkylporphyrins are present in vanadyl porphyrins of petroleums of West Kazakhstan. 2. 2. Vanadyl porphyrins of petroleums of Karazhanbas, Arman and Zhalgyz-Tyube deposits and subsalt petroleums of the Western (near Caspian Sea) region contain cyclic substituents ...
S BAKIROVA +4 more
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Recovery of vanadyl porphyrins from crude oil by complexing
Chemistry and Technology of Fuels and Oils, 19751. A new method has been proposed for the recovery of the porphyrinized fragments of crude oil, this method being based on the formation of hydrocarbon-insoluble molecular complexes with metal halides. 2. It has been shown that metal porphyrins can be recovered from crude oil in the form of complexes with titanium tetrachloride and that ...
N. P. Eletskii +2 more
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An investigation of the vanadyl porphyrin complexes of the athabasca oil sands
Geochimica et Cosmochimica Acta, 1966Abstract The Athabasca oil sands contain, besides the vanadium porphyrin pigments of normal spectroscopic type common to petroleum deposits, a small amount of an abnormal type. This minor component has been partly separated and concentrated, and its structure has been investigated by decomposition and reformation. It appears to be the vanadyl complex
M.F. Millson +2 more
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