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A comparative analysis of the composition of vanadyl porphyrins isolated from heavy oil using two different sulfocationites has been carried out. As a source of vanadyl porphyrins, heavy oil of Volga-Ural basin characterized by a high vanadium content was used. The N,N-dimethylformamide extract of asphaltenes was derived from this oil and subjected for isolation of primary vanadyl porphyrin concentrate on a SiO2 column, which was then chromatographically purified with sulfocationite by our improved method. Strongly acidic cation-exchange resin and asphaltene sulfocationite recently developed in our laboratory were used as sulfocationites. According to ultraviolet–visible spectroscopy, both sulfocationites showed excellent applicability for purification, providing isolation of a broad (>50%) fraction of vanadyl porphyrins with higher spectral purity compared to results of conventional methods. Results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis showed that composition of isolated vanadyl porphyrins depends upon the chemical nature of sulfocationite. Despite the same range of vanadyl porphyrin homologues (C26–C40, with maximum falling on C32) isolated by both sulfocationites, purification with asphaltene sulfocationite resulted in a 1.4-fold decrease in the content of the most abundant DPEP type of vanadyl porphyrins, with a corresponding 1.1–1.9-fold increase in the content of the rest of the types. It was also established that, when purification is accomplished, a significant part of the same vanadyl porphyrins still remains in the column, which can be explained by their associations with non-porphyrin components of the oil.

Extraction by N,N-dimethylformamide with further column chromatography allowed obtaining concentrate of vanadylporphyrins from asphaltenes of heavy sulfurous oils with high vanadium content. The prevailing types of vanadylporphyrins, their ratio, and molecular mass distribution were determined. The influence of obtained vanadylporphyrin concentrates on the stability of asphaltenes in the system “solvent/precipitator” was investigated. Kinetic studies using UV–vis spectroscopy have revealed that an increase in the content of vanadylporphyrins in asphaltenes leads to acceleration of their deposition from solution and destabilization of colloidal systems.

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