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NMR Analysis of Asphaltenes Separated from Vacuum Residues by Selected Solvents

Abstract The characterization of petroleum asphaltenes from different sources has been the object of much current research. However, even employing standard separation methods to obtain representative samples, certain variations in properties are observed. In the present work, we report the results of combining solvent extraction with isolation procedures. We fractionated three asphaltenes obtained from vacuum residues by the IP‐143 method by ethyl acetate, acetone, methyl isobutyl ketone, acetyl acetone, and carbon tetrachloride as single solvents or in a given sucession. The extracts were isolated, weighed and analyzed by IR and 1H NMR. Our results indicate that the solubility of asphaltene constituents in these solvents is affected by the presence of certain aromatic ring systems and saturated chains or rings. The solubility of certain constituents does not depend exclusively on the polarity of the solvent.