ELECTRICAL-CONDUCTIVITY OF ASPHALTENES IN ORGANIC-SOLVENTS

Conductivities of asphaltenes were measured as a function of concentra tion in solvents of varying permittivity. The molar conductivity was c alculated assuming the molecular weight of asphaltenes to be 1000 g/mo l. The Fuoss conductivity model was fitted to the experimental data wi th two free parameters i.e. the association constant and the molar con ductivity at infinite dilution. The experimental data show indication of ion-pairs and strong dipole-ion interaction. Accordingly, the measu rements were consistent with the model for ion pairs as given by Fuoss and multibody interaction theory given by Petrucci. At low concentrat ion the asphaltenes consist mainly of free ions, as the concentration increases ion pairing leads to a decrease of the molar conductivity. A t higher concentration ion-dipole interaction may lead to an increase of the molar conductivity, as is seen in some of the solvents. At even higher concentrations some indications of aggregation are observed. T he results indicate that part of the asphaltenic fraction is ionized a nd behave as ions in solvents of low dielectric constant.