Sulfur K-edge x-ray absorption spectroscopy of petroleum asphaltenes and model compounds

• Published in: Journal of the American Chemical Society Vol. 111; no. 9; pp. 3182 - 3186
• Main Authors: George, Graham N, Gorbaty, Martin L
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.04.1989
• Subjects: 02 PETROLEUM; 023000 - Petroleum- Properties & Composition; 400102 - Chemical & Spectral Procedures; ABSORPTION; ABSORPTION SPECTROSCOPY; Applied sciences; ASPHALTENES; ASPHALTS; BITUMENS; CHEMICAL ANALYSIS; Constitution and properties of crude oils, shale oils, natural gas and bitumens. Analysis and characteristics; Crude oil, natural gas and petroleum products; DATA; ELECTROMAGNETIC RADIATION; Energy; ENERGY SOURCES; Exact sciences and technology; EXPERIMENTAL DATA; FOSSIL FUELS; FUELS; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IONIZING RADIATIONS; K ABSORPTION; NUMERICAL DATA; ORGANIC COMPOUNDS; OTHER ORGANIC COMPOUNDS; PETROLEUM; QUANTITATIVE CHEMICAL ANALYSIS; RADIATIONS; SPECTROSCOPY; SULFUR COMPOUNDS; TAR; X RADIATION; Asphaltene; X ray absorption spectrometry; Content; Chemical structure; Experimental study; Sulfur; Petroleum
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00191a012

The utility of sulfur K-edge X-ray absorption spectroscopy for the determination and quantification of sulfur forms in petroleum asphaltenes has been investigated. Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra were obtained for a selected group of model compounds and for several petroleum asphaltene samples. For the model compounds the sulfur XANES was found to vary widely from compound to compound and to provide a fingerprint for the form of sulfur involved. The use of third derivatives of the spectra enabled discrimination of mixtures of sulfidic and thiophenic model compounds and allowed approximate quantification of the amount of each component in the mixtures and in the asphaltene samples. These results represent the first demonstration that nonvolatile sulfur forms can be distinguished and approximately quantified by direct measurement.