Biomarcadores acidos da bacia Sergipe-Alagoas e estudos sinteticos de esteranos monoaromaticos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

This research work has ultimate objective of addressing three issues. The first issue envolves the investigation of acidic biomarkers present in 10 oil samples of Carmopolis oil Field of Sergipe-Alagoas Basin, which have a marine-evaporitic origin. The main classes of carboxylic acids biomarkers which were characterized as their methyl ester or their deuterium labeled derivatives were n-alkanoic, isoprenoic, steranoic, alkylsteranoic, alkyl-monoaromaticsteranoic, and hopanoic acids. The molecular distribution of the 10 oil samples were compared revealing that immature organic matter was incorporated during migration. Comparison of neutral and acidic biomarker molecular distribution within the same oil sample was shown to be an efficient probe to the functionality of the diagenetic oxygenated precursor. Thus biomarker classes possessing a molecular distribution with a carbon atom shift between the acidic and the neutral counterpart ought to have a carboxylic acid diagenetic precursor while those with similar molecular distribution in the acidic and neutral fraction ought to have an alcohol or ether as diagenetic precursor. Though simple this is the first time that such a rational is applied to petroleum investigation and to reveal the true nature of the depositional environment. More data are certainly required to finally consolidate this theory but only few examples comparing acidic and neutral fraction are available in the literature. The second issue refers to the synthesis of two biomarkers standards: 4a-methyl- 1,2,3,4,4a,9,10,10a-octahydrofenanthrene and 4-(2 -phenyl-ethyl)-3-methyl- cyclohexane which might arise from steranes submitted to aromatization and ring opening. A diastereoselective Heck-Michael reaction was applied to the synthesis of octahydronaphthalene during an intramolecular ring closure. Finally the third issue we have addressed refers to the application of NOE difference and longitudinal relaxation T1 measurements to predict the Claisen rearrangement regioselectivity of the allyl tetrahydronaphthalenyl ethers, which was successfully applied to the synthesis of the above biomarkers.

ASSUNTO(S)

reações quimicas petroleo compostos aromaticos

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