Mass spectrometric studies on porphyrins and geoporphyrins

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:210700

Quirke, J; Martin, E ^[1]; Yost, R A ^[2]

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1. Florida International Univ., Miami, FL (United States)
2. Univ. of Florida, Gainesville, FL (United States); and others

Porphyrins are among the more important compound classes, playing significant roles in such diverse areas as medicine, material sciences, catalysis and the petroleum industry. The most valuable property of the porphyrin macrocycle is its ability to chelate with any metallic element. In organic geochemistry, geologically-occurring porphyrins, geoporphyrins, are of both academic and commercial consequence. Geoporphyrins occur as complicated mixtures of nickel(II) and vanadyl(II) [VO(II)] complexes in a wide range of sedimentary environments. They are believed to be formed by transformation of the functional groups of biologically-occurring cyclic tetrapyrroles, especially chlorophyll a into alkyl or hydrogen substituents coupled with the oxidation of the chlorin (dihydroporphyin) to the porphyrinic system. This proposal, the Treibs` hypothesis, is the cornerstone of molecular organic geochemistry. The precise composition of geoporphyrin mixtures varies from crude oil to crude oil. For this reason, analysis of geoporphyrin mixtures is a valuable tool for the correlation of crude oils with other oils and/or source rocks. Less happily, the geoporphyrins, especially the vanadyl complexes, poison catalysts in cracking of crude oil and industrial processes. Mass spectrometry is perhaps the most valuable too for analysis of geoporphyrin mixtures. Such analyses present the mass spectrometrist with several challenging problems. Geoporphyrin mixtures are composed of overlapping pseudohomologous series least nine skeletal types. Carbon number ranges of C{sub 28}-C{sub 50} are not uncommon. The upper limit of the carbon number range is still unclear.

• OSTI ID: 210700
• Report Number(s): CONF-9505261--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
CHEMICAL ANALYSIS
GEOCHEMISTRY
MASS SPECTROSCOPY
PETROLEUM
PORPHYRINS