Changes in Structural Group Composition of Asphaltenes and Carbene-Carboids of the Domanic Shale in Sub- and Supercritical Water: FT-IR Spectroscopy Data

Abstract

This paper presents the results of a change in the structural-group composition of asphaltenes and carbonaceous substances such as carbene-carboids in the products of the conversion of high-carbon Domanic rock from the sediments of the Semulukskoe-Mendimskoe horizon of the Volga-Ural petroleum basin, after exposure at temperatures of 320, 374 and 420 ?C in sub- and supercritical water. IR Fourier spectroscopy showed that increasing the temperature to supercritical water conditions (374 and 420 ?C) leads to chemical transformation of high molecular weight components and Domanic kerogen, accompanied by the formation of carbinecarboids - polymerization and condensation products that differ from asphaltenes in a higher degree of aromaticity. The highest content of carbene-carboids is observed in the composition of the products obtained from experiments at 374 ?C, apparently associated with intensive decomposition of kerogen of Domanic rock. Increasing the temperature to 420 ?C leads to the formation of coke-lake products as a result of oxidative degradation processes, which leads to a decrease in their content in liquid hydrocarbons.