Properties of the Polar Fraction of Hassi-Messaoud Asphaltenes

Abstract

Polar fractions of Hassi-Messaoud asphaltenes were obtained by two different extraction/precipitation procedures. Properties of these fractions were studied using elemental analysis, LDI-TOF mass spectroscopy, and solid state 13C NMR. The aggregation and the flocculation onset of polar fractions were determined. It was demonstrated that the most polar fraction of asphaltenes that is soluble in highly polar solvents, such as N-methyl pyrrolidone and nonsoluble in mildly polar or nonpolar solvents is composed of small molecules, containing a high oxygen ratio. This fraction plays an important role in asphaltene aggregate formation. The understanding of this role would be helpful for designing new antiflocculation agents.