Results 121 to 130 of about 370 (171)

A Comparative Analysis of Vanadyl Porphyrins Isolated from Resins of Heavy Oils with High and Low Vanadium Content

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.
M R Yakubov, G R Abilova, E G Tazeeva
exaly   +2 more sources

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Observation of vanadyl porphyrins and sulfur‐containing vanadyl porphyrins in a petroleum asphaltene by atmospheric pressure photonionization Fourier transform ion cyclotron resonance mass spectrometry

Rapid Communications in Mass Spectrometry, 2008
Abstract Vanadyl (VO) porphyrins and sulfur‐containing vanadyl (VOS) porphyrins of a wide carbon number range (C 26 to C 52 ) and Z‐number range (−28 to −54) were detected and identified in a petroleum asphaltene by atmospheric ...
Kuangnan Qian, Anthony S Mennito, Kathleen E Edwards   +2 more
exaly   +3 more sources

Classification of the asphalts and their source rock from the Dead Sea Basin (Israel): the asphaltene/kerogen vanadyl porphyrins

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
exaly   +2 more sources

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 ...
Pajovic, MT, Tonsa, Ivana R., Lopez, L, M.S. Pavlović, Lopez, Liliana, I.R. Tonsa, P.I. Premović, M.T. Pajović, Monaco, SL, Premović, Pavle I., L. Lopez, Tonsa, IR, D.M. Đorđević, Premovic, PI, Dordevic, DM, Pavlović, Mirjana S., S.L. Monaco   +16 more
exaly   +2 more sources

Vanadyl porphyrins in sedimentary kerogens/asphaltenes: Estimation of the concentration

, 1999
A new, rapid method for determining the concentration of vanadyl porphyrins (VO2+-P) associated with the kerogen of bituminous sedimentary rocks, using electron spin resonance (ESR) is described. The method is simple, straightforward and inexpensive. Several concentrations of a vanadyl (VO2+) standard dissolved in glycerol/lignite mixture were prepared.
Premović, Pavle I., Allard, Thierry, Nikolić, Nikola D., Tonsa, Ivana R., Pavlović, Mirjana S.   +4 more
openaire   +2 more sources

Chemistry of Vanadyl Porphyrins

Tetrahedron, 1978
Abstract 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, Peter Brewer, K. Noro, T. Noro   +3 more
openaire   +1 more source

Diastereoisomers in sedimentary vanadyl porphyrins

Energy & Fuels, 1990
The 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, Peter S. Clezy, Glen B. Robertson   +2 more
openaire   +1 more source

ChemInform Abstract: CHEMISTRY OF VANADYL PORPHYRINS

Chemischer Informationsdienst, 1978
AbstractDurch 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
openaire   +1 more source

Electrochemical studies of tetraphenylporphyrin and vanadyl porphyrin

Science in China Series B: Chemistry, 1997
The electrochemical reductions and oxidations of tetraphenylporphyrin (TPP) and vanadyl porphyrin (TPP-VO) were investigated in dimethylformamide at platinum, glass carbon and microdisk electrodes. A new electrode reaction mechanism of TPP and TPP-VO is proposed. The kinetic parameters have also been determined.
Qiankun Zhuang, Xiaoxia Gao
openaire   +1 more source

Comparison of maturity based on steroid and vanadyl porphyrin parameters: A new vanadyl porphyrin maturity parameter for higher maturities

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, J.Michael Moldowan   +1 more
openaire   +1 more source