This article collects the work performed by Isothermal Titration Caloritnetry (ITC) in the study of the self-association of asphaltenes in toluene solutions. Calorimetric experiments show that asphaltenes, start self-associating at very low concentrations and that the existence of a Critical Micellar Concentration is rather. improbable. The influence of the water dissolved in the-toluene has been studied but the difficulties in keeping the water concentration low hinder the discussion of the results. The calorimetry data have been treated with a simple dimer dissociation model and compared with the results of the titration of three model molecules: nonylphenol, which associates by means of hydrogen bond formation, and coronene and pyrene, which associates by stacking. The results obtained leave open the question about the model-stacking molecules, as it was not possible to elucidate whether they do not associate or the dilution effect does not break the aggregates. The fluorescence spectroscopy results support the results of calorimetry with respect to the self-association at low concentrations. ITC has been applied for the first time to the study of the interaction between asphaltenes and a model resin, namely nonylphenol.
|Journal||Petroleum Science and Technology|
|Publication status||Published - 2002|
|Event||3rd International Conference on Petroleum Phase behavior and Fouling - New Orleans, United States|
Duration: 10 Mar 2002 → 14 Mar 2002
Conference number: 3
|Conference||3rd International Conference on Petroleum Phase behavior and Fouling|
|Period||10/03/2002 → 14/03/2002|