Solid Petroleum Asphaltenes Seem Surrounded by Alkyl Crowns

摘要

In this article, an analysis of the results obtained in our laboratory and published in the literature is presented, which points toward the existence of alkane layers surrounding precipitated asphaltene aggregates. A micellar model for asphaltenes has been proposed, which explains many of the experimental determinations carried out to date with these compounds. The model considers the existence of alkane moieties surrounding the inner aromatic cores. Faster dissolution kinetics of asphaltenes modified by coprecipitated alkanes have been explained by the enhanced incorporation of alkane-surrounded particles into the eluent employed in the dissolution experiments. Finally, asphaltene volumetric changes brought by organic solvents have recently been studied, and can be explained by the existence of an alkane shell prone to the incorporation of solvent molecules. This paper will discuss these aspects that seem to support the model long time ago postulated by Yen.