Studies of the electrical conductivities of fractions from the Athabasca bitumen indicate that these materials possess appreciable conducting properties. This can be ascribed, in part, to the network of condensed aromatic systems which occurs in this material and it is possible to co-relate the conductivity data and theoretical postulates of micelle structure.
In previous communications from these laboratories (reference 1, and references cited therein), we have attempted to show that petroleum asphalteneshave a variety of interesting structural and chemical properties which render them suitable for a myriad of non-fuel uses. As a further part of this research programme, we have commenced an investigation of the physical properties of these materials. In particular, the present investigation relates to the solution properties of the asphaltenes, since we* and others3'4 have previously noted that these materials will associate even in dilute solution in solvents having low dielectric constants. Such behaviour can be advantageously utilized during the processing of a crude oil -as, for example, in the deasphalting step in a refinery operation'. However, it is essential to have a detailed knowledge of the solution properties of these materials if a thorough understanding of various processes is desired.
Therefore, it was of interest to us to expand these studies of the solution properties of asphaltenes and we chose to examine changes that occurred in the electrical conductivity when these materials were dissolved in various organic solvents. It was hoped that such a study would throw further light on the physical structure of the asphaltene micelle and its behaviour in solution. Briefly, the electrical conductivity of aromatic hydrocarbons originates in the mobility of the n-electrons in the modular planes, and hence it is not surprising that, at say room temperature, the conductivity of aromatic hydrocarbons generally increases with increasing ring number -gradually approaching that of graphite6. The position of petroleum asphaltenes on a scale of this type remains largely uncertain presumably because of the lack of work in this particular area. Although earlier reports indicate that the electrical conductivities of hydrocarbon oils7 or asphaltic bitumen' are quite small -within the range of 10-14-10-21 mholm -'t 1 appears that the only previously published report on the electrical conductivity of asphaltenetype materials was that by Sill and Yen'. These workers noted that the electrical conductivity of two petroleum asphaltenes (in the solid phase) fell in the insulator range < lo-l6 mho/m.