Home – Home – Jornals – Chemistry for Sustainable Development 2026 number 4

The effect of acylation of petroleum tar with trifluoroacetic anhydride on its chemical composition and colloidal stability has been studied. Tar contains a large amount of polycyclic aromatic hydrocarbons (including resins and asphaltenes) capable of acylation by the Friedel-Crafts reaction. The introduction of oxygen- and fluorine-containing functional groups increases the polarity of molecules and changes the colloidal stability of petroleum disperse systems. In the course of work, the duration of acylation process (1, 4 or 8 h) and the concentration of trifluoroacetic anhydride (5, 15 or 25 wt%) were varied both in the presence of a catalyst (anhydrous aluminium chloride) and without it. Analysis of the composition, structure, and colloidal stability of tar and acylation products was carried out using NMR ¹H spectroscopy, IR spectroscopy, liquid adsorption chromatography, and spectrophotometry. It has been shown that acylation without the catalyst leads to insignificant changes in the composition. The use of the catalyst promotes more pronounced chemical transformations, increasing the asphaltene content and reducing the proportion of resins while maintaining the oil level. With an increase in the reaction duration and anhydride concentration, the oxygen content, average molecular weight and content of hydrogen atoms in the α-position to the aromatic nuclei and functional groups increase. An increase in the reagent concentration to 25 wt% and the duration of catalytic acylation to 8 h causes a significant decrease in the colloidal stability of the product. Optimum conditions for obtaining a product with high sedimentation stability (77-79 %) are achieved under the following conditions: the concentration of trifluoroacetic anhydride 25 wt%, synthesis duration 1 h.