In the present work, the first data on the catalytic activity of d-metal complexes of petroleum porphyrins obtained via two-stage re-metallization (acid demetallization with subsequent metalation) of high-purity petroleum vanadyl porphyrins are presented. During acid demetallization of petroleum vanadyl porphyrins, the highest yield (49%) and spectral purity of free petroporphyrin bases were achieved with concentrated sulfuric acid and a diluted solution of vanadyl porphyrins in chloroform. In the series of divalent cations of Mn, Fe, Co, Ni, Cu, and Zn, only the last four metals are complexed with demetallated petroporphyrins without significant changes in their component composition, whereas the interaction with Mn and Fe cations causes an evident structural transformation or even full degradation of petroporphyrin macrocycles, respectively. The composition and spectral purity of petroleum porphyrin-containing reactants and products were analyzed by FT-IR, UV-Vis, NMR, and MALDI-TOF mass spectroscopic methods. The obtained petroporphyrin-based d-metal complexes were assayed by the reaction of 2-mercaptoethanol oxidative dimerization, in which the copper porphyrins exhibited the highest catalytic activity.

In this work, variations of heavy oil asphaltenes’ oxidation reactions under different conditions were investigated. By IR spectroscopy was shown a predominant destruction of occluded and adsorbed compounds in asphaltenes when using KIO₃ and NaIO₄ as oxidizing agents. In the case of CH₃COOH/H₂O₂ and KMnO₄ was determined the destruction of asphaltenes supermolecules with a formation of carboxyl groups. EPR spectroscopy demonstrated decrease of content of vanadyl complexes spin per gram of oxygenates 0.5–2 times in comparison with initial asphaltenes, which indicates the separation of occluded metalloporphyrins. Content of free stable radicals in high molecular products increased in 2–4 times.

The composition of purified vanadyl porphyrins recovered from the resins of heavy oils possessing high and low vanadium contents was investigated. Vanadium content in the resins of the heavy oils under study differs by a factor of ca. 15. To recover and purify vanadyl porphyrins from the resins, extraction by N,N–dimethylformamide (DMF) with subsequent two-stage column chromatography on silica gel and sulfocationite were employed. The change of structural-group composition and content of vanadyl porphyrins in the products obtained at each stage was evaluated using Fourier IR and UV-Vis spectroscopy. Analysis of the purified vanadyl porphyrins using MALDI mass spectrometry determined distribution of their most abundant types (etio- and DPEP) and identified C₂₇–C₃₉ homologs for the resins possessing high vanadium content and C₂₈–C₃₉ homologs for the resins with low vanadium content.

High-vanadium heavy oil asphaltenes were fractionated by a sequential precipitation method. Using FT-IR spectroscopy, elemental analysis, and optical spectroscopy, the differences in the compositions of the asphaltene fractions were thoroughly investigated. To isolate and purify vanadyl porphyrins (VPs) from the asphaltenes, extraction with N,N-dimethylformamide (DMF) followed by two-step column chromatography on silica gel and sulfocationite was employed. The effects of VPs on the solubility of the asphaltene fractions were evaluated based on optical density variations in the solvent/precipitant system in a kinetic mode. It was found that, in most cases, adding petroleum VPs to toluene solutions of asphaltene fractions decreases the solubility of these fractions. The highest effect of VPs on the solubility of the asphaltene fractions was observed for samples with a high concentration of polar heteroatom groups and low aromaticity.

Using simultaneous thermogravimetry and differential scanning calorimetry, thermal stability and possible phase transitions of asphaltene sulfocationites and native asphaltenes have been evaluated; the kinetic characteristics of heating have been determined, namely, onset temperature of decomposition, stages of decomposition, and temperature ranges of stability. It has been determined that asphaltene sulfocationites retain structural-group features (IR spectroscopy method) and sorption characteristics while heating up to 350 °C.

A series of experiments has been carried out on the thermolysis of heavy oil using 2.5–10.0% light hydrocarbon naphtha additive of vacuum gasoil prepared from conventional oil. It has been shown that the employment of the additive increases the conversion of heavy oil, avoids coke formation in the products of thermolysis as compared to the basic process without additive, and does not prevent the decrease in the viscosity of the products during thermolysis. It has been revealed on the example of the heavy oil of Ashal’chinskoe deposit (Russia) that the thermolysis with the addition of light naphtha gives a liquid product with the yield higher than 97% and the viscosity of less than 80 mm²/s.