Synthesis, characterization, and mechanism of asphaltene inhibition of phosphopropoxylated asphaltenes

Phosphopropoxylated asphaltenes were synthesized by functionalizing the Mexican VR asphaltenes with phosphorus trichloride and then reacting the product with different polypropylene oxides. Elemental analysis, and molecular weight characterization showed that in average one atom of phosphorus and one propoxyl moiety are incorporated to the asphaltenes. Phosphopropoxylated asphaltenes were found active for the reduction of asphaltene content of gravimetrically separated asphaltene solutions and a hydroprocessed product at 35 °C and 195 °C. Volumetric measurements, fluorescence spectroscopy, and solubility determinations were used to study the aggregation behavior of phosphopropoxylated asphaltenes. The results indicate that the mechanism of asphaltene inhibition seems to be related to the ability of these molecules to disrupt the π-π interactions between the polyaromatic moieties of the asphaltenes, inhibiting asphaltene stacking.