Structural investigation of nonpolar sulfur cross-linked macromolecules in petroleum

Conference · Thu Jul 01 04:00:00 EDT 1993 · Geochimica et Cosmochimica Acta; (United States)

OSTI ID:5814882

Adam, P; Schmid, J C; Mycke, B; Albrecht, P ^[1]; Strazielle, C ^[2]; Connan, J ^[3]; Huc, A ^[4]; Riva, A ^[5]

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1. Universite Louis Pasteur, Strasbourg (France)
2. Institut Charles Sadron, Strasbourg (France)
3. Elf Aquitaine, Pau (France)
4. Institut Francais du Petrole, Rueil-Malmaison (France)
5. San Donato Milanese-Milano (Italy)

A novel hexane-soluble nonpolar macromolecular fraction (NPMF) has been found to occur in substantial amounts (up to 32%) in sulfur-rich crude oils and a rock extract. It is highly aliphatic and has a molecular weight culminating at several thousand mass units, as proven by spectroscopic and molecular weight studies. C-S bond hydrogenolysis of NPMF with Raney nickel as a catalyst yields high proportions of aliphatic hydrocarbons in which long linear, acyclic polyisoprenoid and carotenoid chains usually predominate (except in one case) over polycyclic structures, such as steroids and hopanoids. Hence, NPMF consists mainly of macromolecules composed of low molecular weight hydrocarbon subunits cross-linked with sulfide bridges. Use of deuterated Raney nickel indicated in one case (Rozel Point oil) that the long chains and some hopanoids are multiattached to the macromolecular network, whereas other structural subunits, such as steroids or gammacerane, are essentially monoattached. Detailed structural determinations of the hydrocarbon [open quotes]building blocks[close quotes] of NPMF give information on their origin and the mode of formation of these macromolecules in the subsurface. Indeed, most of the building blocks can be related to algal (e.g., long linear chains, steroids, [beta]-carotene, and related carotenoids) or bacterial (e.g., acyclic and monocyclic carotenoids, long-chain acyclic isoprenoids) pre-cursors which essentially exist in living organisms as monounsaturated or polyunsaturated species or are easily transformed into such species by diagenetic processes (e.g., steroids). It appears that these alkenes or polyenes become selectively trapped into a macromolecular network by reaction with inorganic sulfur species produced by bacteria in a kind of natural, low-temperature, vulcanization process. This process could start at early diagenesis already in the water column or eventually continue in the bottom sediment.

• OSTI ID: 5814882
• Report Number(s): CONF-911017--; CNN: ST2-0225
• Conference Information: Journal Name: Geochimica et Cosmochimica Acta; (United States) Journal Volume: 57:14
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
023000* -- Petroleum-- Properties & Composition
ALGAE
ALKENES
BACTERIA
CAROTENOIDS
CHEMICAL BONDS
CHEMICAL COMPOSITION
DIENES
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
ISOPRENE
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PETROLEUM
PIGMENTS
PLANTS
POLYENES
POLYMERS
SOUR CRUDES
TERPENES