Rearranged hopanes in sediments and petroleum

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90492-N· OSTI ID:5219187

Moldowan, J M; Fago, F J; Carlson, R M.K. ^[1]; Young, D C ^[2]; Van Duyne, G; Clardy, J ^[3]; Schoell, M ^[4]; Pilinger, C T ^[5]; Watt, D S ^[6]

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1. Chevron Oil Field Research Co., Richmond, CA (United States)
2. Chevron Research and Technology Co., Richmond, CA (United States)
3. Cornell Univ., Ithaca, NY (United States)
4. Chevron Oil Field Research Co., La Habra, CA (United States)
5. Open Univ., Walton Hall, (United Kingdom)
6. Univ. of Kentucky, Lexington (United States)

Two new rearranged hopanoid hydrocarbons have been isolated from a Prudhoe Bay crude, Alaska. 17{alpha}(H)-15{alpha}-methyl-27-norhopane was determined by X-ray crystallography. It is the first identified member of a new series of rearranged hopanes the authors propose to call 17{alpha}(H)-diahopanes. Analysis by gas chromatography-mass spectrometry-mass spectrometry (GC-MSS-MS) of the parents of m/z 191 in several crudes suggests that this compound is a member of a C{sub 29}-C{sub 34}series of 17{alpha}(H)-diahopanes common to many crude oils and sediments. In addition, a new member of the 18{alpha}(H)-neohopane series has also been elucidated. Determination of 18{alpha}(H)-17{alpha}-methyl-28,30-dinorhopane (18{alpha}(H)-30-norneohopane), which the authors propose to nickname C{sub 29}Ts, hinged upon advanced nuclear magnetic resonance (NMR) techniques (at 500 and 600 MHz) such as proton-detected {sup 1}H-13 correlated spectra for the C-skeleton and Rotating-frame Overhauser Enhancement Spectroscopy (ROESY) for stereochemistry, as well as several other two-dimensional (2D) NMR techniques. The structures of these rearranged hopanes are consistent with an origin by catalytic rearrangement from hopanes during early diagenesis. Carbon isotopic data collected on Ts, 17{alpha}(H)-diahopane, C{sub 29}Ts, 17{alpha}(H)-22,29,30-trisnorhopane (Tm), 17 {alpha}(H)-30-norhopane, and 17{alpha}(H)-hopane isolated from the Prudhoe Bay oil are in the {minus}27 to {minus}28% {delta}{sup 13}C range supporting mechanistic arguments based on structures that all are derived from common precursors. These {delta}{sup 13}C values are slightly more positive than the whole Prudhoe Bay oil ({minus}30.1%), suggesting that these hopanes may have been derived from heterotrophic or cyanobacteria in the paleoecosystem during deposition of its source rock.

• OSTI ID: 5219187
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:11; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
023000* -- Petroleum-- Properties & Composition
58 GEOSCIENCES
580000 -- Geosciences
CARBON ISOTOPES
DIAGENESIS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
ISOTOPE RATIO
ISOTOPES
MAGNETIC RESONANCE
MASS SPECTROSCOPY
MATURATION
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
PETROLEUM
RESONANCE
SEDIMENTS
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS