Fractionation of Aschalcha extra heavy oil resins and studying their structure

Abstract

© 2020 IOP Publishing Ltd. All rights reserved. In this paper we isolated resins from a sample of extra heavy oil and from the products of catalytic aquathermolysis in the presence of a cobalt based catalyst and studied their structure. In fact, an oil fraction and 4 resin fractions (R1-R4) have been extracted by liquid adsorption chromatography method in the presence of pure solvents and their binary mixtures in various ratios. Adding the catalyst to the system during heat and steam exposure for 6 hours leads to a significant improvement of the structural-group composition. Thus, the aliphaticity index of R3 decreased as a result of the detachment of alkyl substituents in aromatic fragments under the influence of catalyst and passes into lighter fractions of resins, as well as towards saturated and aromatic hydrocarbons. From another hand, the oxidation coefficient also manifests itself in fractions R1 and R2 as a result of oxidative catalytic cracking processes, which also indicates a redistribution of the group composition. MALDI data have showed that the average molecular weight of resins for each of the fractions has decreased whereas IR spectroscopy has highlighted a change in their structural group composition.