The aggregation and sedimentation behavior of asphaltenes in the presence of two naphthenic acids, methyl abietate and hydrogenated methyl abietate were investigated using dynamic light scattering (DLS), near-infrared spectroscopy (NIR), and molecular modeling. Aggregation behavior of asphaltenes was monitored as a function of added precipitant (n-heptane) to solutions of suspended asphaltenes and naphthenic acids in model solutions of toluene/n-heptane, and onsets of flocculation were determined. In this work, it was demonstrated that DLS and NIR show very good correlation in indentifying the onsets of flocculation. Interaction energies of asphaltenes and naphthenic acids were calculated using molecular mechanics. The results from molecular modeling calculations support the experimental results of the titrations.
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