Results 111 to 120 of about 23,032 (162)
Processes, 2021 The composition of purified vanadyl porphyrins recovered from the resins of heavy oils possessing high and low vanadium contents was investigated. Vanadium content in the resins of the heavy oils under study differs by a factor of ca. 15.
Svetlana G Yakubova +2 more
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Electron spin resonance study of the kerogen/asphaltene vanadyl porphyrins: air oxidation
Fuel, 2001 Thermal behavior of vanadyl porphyrins was studied by electron spin resonance during heating of the kerogens isolated from the La Luna (Venezuela), Maganik(Montenegro) and Serpiano (Switzerland) bituminous rocks at 150 and 250 degreesC for 1 to 20 days ...
L Lopez
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Fuel, 1998 The asphaltenes of the asphalts from the Dead Sea Basin were examined for the presence of vanadyl porphyrins. These examinations demonstrated that the asphalts fall into two broad class types, one having a relatively high vanadyl prophyrins content ( GT ...
Pavle I Premović, Mirjana S Pavlovic
exaly +2 more sources
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Molecular composition of vanadyl porphyrins in the gilsonite
Journal of Fuel Chemistry and Technology, 2020Abstract A gilsonite from Qingchuan (Sichuan province, China) was separated into several fractions and characterized by various techniques. The vanadyl porphyrins were determined by inductively coupled plasma optical emission spectrometer, ultraviolet-visible spectrophotometry, high-temperature gas chromatography-atomic emission detector, and ...
Fang ZHENG +4 more
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Chemistry of Vanadyl Porphyrins
Tetrahedron, 1978Abstract The chemistry of vanadyl porphyrins has been explored using vanadyl octaethylporphyrin as the type substance, and with special reference to the occurrence of such substances in petroporphyrins. Spectroscopic properties (electronic spectra, IR spectra, mass spectra) are described, and electronic spectra are employed to detect the occupation ...
R. Bonnett +3 more
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Diastereoisomers in sedimentary vanadyl porphyrins
Energy & Fuels, 1990The observation that the product of vanadyl insertion into the free-base porphyrin 15 I -methyl-15,17-propanoporphyrin separated into two near equal area peaks on HPLC analysis precipitated an investigation into the structure of both vanadyl porphyrins.
Christopher J. Boreham +2 more
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ChemInform Abstract: CHEMISTRY OF VANADYL PORPHYRINS
Chemischer Informationsdienst, 1978AbstractDurch Reaktion von Oktaethylporphyrin mit Vanadylsulfatdihydrat in Essigsäure‐Pyridin (2 : 1) in der Siedehitze wird die Verbindung (Ia) erhalten.
R. BONNETT, P. BREWER, K. NORO, T. NORO
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Geochimica et Cosmochimica Acta, 1993
Abstract Correlations are demonstrated between steroid maturity parameters and the porphyrin maturity parameter (PMP) which is based on the ratio of specific vanadyl porphyrins C 28 E (C 28 E + C 32 D) measured by HPLC. Measurements from a global selection of > 100 rock extracts and oils show that PMP parallels changes in the
Padmanabhan Sundararaman +1 more
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Abstract Correlations are demonstrated between steroid maturity parameters and the porphyrin maturity parameter (PMP) which is based on the ratio of specific vanadyl porphyrins C 28 E (C 28 E + C 32 D) measured by HPLC. Measurements from a global selection of > 100 rock extracts and oils show that PMP parallels changes in the
Padmanabhan Sundararaman +1 more
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The interaction of vanadyl porphyrin with the HY zeolite surface
Journal of Molecular Catalysis A: Chemical, 2009The interaction of vanadyl porphyrin with the acid sites of the HY zeolite surface is investigated. Structural changes, partial population charges and relative energies induced by the interaction between vanadyl porphyrin and the zeolite surface are estimated with recourse to the Born-Oppenheimer semiclassical molecular dynamics technique in ...
I.P. Zaragoza, R. Santamaria, R. Salcedo
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Vanadyl Tetrakis(pentafluorophenyl)porphyrin Dichloromethane Solvate
Acta Crystallographica Section C Crystal Structure Communications, 1998The vanadyl complex oxo[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato-κ 4 N]vanadium(IV) dichloromethane solvate, [VO(C 44 H 8 F 20 N 4 )].CH 2 Cl 2 , crystallizes in the monoclinic space group P2 1 /c, with four molecules per unit cell. The V atom is found to lie . 0.5237 (5) A above the mean plane of the porphyrin core.
Duval, H. +3 more
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