Changes in the Composition of Heavy Oil and the Structure of Asphaltenes upon Treatment with Isopropyl Alcohol

The interactions of the components of heavy oil from the Zyuzeevskoye field (Republic of Tatarstan) and isopropyl alcohol (IPA) at temperatures of 25, 65, and 100°C were studied. It was established that the temperature regime affected the density, composition, and structural group characteristics of the products of interactions between the oil and IPA. The density of the resulting products increased by 4 wt % (from 0.885 to 0.924 g/cm3) as the process temperature was increased to 100°C, and the concentration of resin–asphaltene substances also increased by 4 wt % in this case. It was shown using IR spectroscopy that the tentative concentration of paraffin fragments in the structure of asphaltenes increased significantly when the oil was treated with isopropanol at temperatures of 65–100°C, and the branching factor increased by a factor of 3, as compared to that of the initial asphaltenes. The observed changes were due to the incorporation of isopropyl fragments into the structure of asphaltene molecules upon the processing of heavy oil with IPA.