Home – Home – Jornals – Chemistry for Sustainable Development 2023 number 2

The results of a comparative gas chromatographic - mass spectrometric (GC-MS) analysis of the composition of saturated and aromatic hydrocarbons, as well as heteroorganic compounds in petroleum oils isolated from a number of crude oils and natural bitumens, before and after selective chemical cleavage (chemolysis) of C-S and C-O bonds of sulphide and ether/ester bridges, respectively, are presented. The revealed difference in the structural-group and molecular composition of some types of compounds before and after chemolysis indicates that alkanes, alkyltrimethylbenzenes, naphthalenes, phenanthrenes, tetra- and pentacyclic aromatic hydrocarbons, and dibenzothiophenes are present in oils not only as molecular entities, but, partially, as structural fragments linked via sulphide and ether/ester bridges with other fragments in complex high-molecular entities. Ester-bound high-molecular С₂₀-С₃₀ homologues predominate among the bound alkanes. The proportion of C₁₃-C₁₆ homologues among alkyltrimethylbenzenes decreases after chemolysis. Chemolysis is accompanied by an increase in the proportion of С₃-С₄ naphthalenes in petroleum oils. The ratio of homologues among phenanthrenes changes after chemolysis: as a rule, the unsubstituted compound predominates over homologues. The ratio of fluoranthene and pyrene to benzanthracene and chrysene increases among tetracyclic aromatic hydrocarbons. The main trend in the changes in the composition of dibenzothiophenes after chemolysis is a sharp decrease in the proportion of unsubstituted homologue.