Petroleum Chemistry

Gilsonite (natural asphalt) was employed for the first time as a raw material for the preparative isolation of spectrally pure petroleum vanadyl porphyrins using sulfocationite sorbents in an extraction-chromatographic procedure. The isolation process includes sequential extraction of vanadyl porphyrins from gilsonite with N, N-dimethylformamide (DMF), chromatographic fractionation of the extract on moistened silica gel, and final purification of the vanadyl porphyrin concentrate on a silica-gel-based sulfocationite. It was shown that the use of the sulfocationite enables the separation of vanadyl porphyrins into two fractions differing in color (red and green), composition, and spectral characteristics. The red fraction is enriched in etioporphyrin- and DPEP (deoxophylloerythroporphyrin)-type vanadyl porphyrins, whereas the green fraction predominantly contains rhodo derivatives containing a fused benzene ring. The isolated fractions were characterized by UV-visible spectroscopy and MALDI-TOF mass spectrometry. The proposed extraction-chromatographic approach can be applied to evaluate gilsonite as a promising feedstock for the production of natural petroleum porphyrins, which are potential components of functional materials, dyes, catalysts, and photoactive systems.

Modified aluminophosphate carriers were synthesized by the method of impregnation of the industrial γ-Al₂O₃ carrier (Alumac-3, Alumac Construct) with solutions of ammonium hydrophosphate of various concentrations, the physicochemical characteristics of which were determined by the methods of IR spectroscopy, X-ray fluorescence analysis, low-temperature nitrogen adsorption and temperature-programmed desorption of ammonia. Their physicochemical properties were determined using IR-spectroscopy, X-ray fluorescence analysis, low-temperature nitrogen adsorption, and temperature-programmed ammonia desorption. Studies of the carriers showed that increasing the phosphorus concentration in the carrier alters its textural and acidic properties. When phosphorus is added to the carrier, the average pore diameter and volume decrease, and the specific surface area decreases significantly, while the pore size distribution remains unchanged. Temperature-programmed ammonia desorption data indicate a shift in the peaks of acid sites of varying strengths toward higher temperatures and an increase in overall acidity with increasing phosphorus concentration in the carrier. Based on the obtained supports, sulfide CoMoS catalysts were synthesized, followed by a study of their properties in dibenzothiophene (DBT) hydrodesulfurization and naphthalene hydrogenation reactions in the presence of quinoline. It was found that modification of the standard support (γ-Al₂O₃) of the cobalt-molybdenum catalyst with phosphorus (phosphorus content of 0.93 wt%) leads to an increase in conversion in the DBT hydrodesulfurization reaction by 16.1% and in the naphthalene hydrogenation reaction by 3%.