The Chemical Nature of Oxidized Sulphur in Asphaltenes from X-Ray Absorption Spectroscopy

Abstract

Bitumen samples have been chosen either from natural oil seepages and outcropping oil-stained reservoirs or archaeological bitumens from excavations in Iraq and Pakistan. Asphaltenes have been extracted from the bitumens. X-ray absorption near edge fine structure (XANES) spectroscopy at the S L-edge and K-edge has been employed to follow the oxidation effects on various sulphur moieties of the asphaltene fractions. Among asphaltenes extracted from archeological bitumens, sulphoxide, sulphone and sulphate are the predominant oxidized forms of sulphur

Selective Desulfonylation of Oxidized Sulfur Compounds in Crude Oil by Alcohol-Mediated Nucleophilic Attack Studied by XANES and XRF Spectroscopy

“…The various methods of removing sulfur from oxidized sulfur compounds in complex matrices such as crude petroleum and bitumen heighten the need to understand product speciation both before and after desulfurization. X-ray Absorption Near Edge Structure (XANES) spectroscopy is an effective analytical method for determining the speciation of sulfur compounds in petroleum feedstocks, and quantifying the relative abundances of sulfides, thiophenes, sulfoxides, and sulfones [10,[14][15][16][17][18].…”