Pavel I. Gryaznov

Features of the composition of vanadyl porphyrins in the crude extract of asphaltenes of heavy oil with high vanadium content

ABSTRACT Features of changes in the content of nickel and vanadium in heavy oils and their asphaltenes are shown for various fields of Volga-Ural region (Russia). The change in the content of vanadyl complexes in the studied asphaltenes upon increase of vanadium content was demonstrated. Several polar solvents (acetone, N,N-dimethylformamide, isopropanol, acetonitrile) are compared as extractants to obtain crude extracts of vanadyl porphyrins from asphaltenes with vanadium content of 0.44 wt%. The opportunity of more efficient extraction of vanadyl porphyrins from asphaltenes is shown by deposition extraction method, particularly when using N,N-dimethylformamide. Absorption spectra and matrix-assisted laser desorption/ionization (MALDI) mass spectra of the extracts obtained were analyzed. For extracts with maximum content of vanadyl porphyrins, the presence of mainly etio- and deoxophylloerythroetioporphyrins was revealed. It was shown that proportion of etio-type vanadyl porphyrins does not exceed 75% of the amount of porphyrins of DPEP-type. A maximum of molecular weight distribution in both types falls on a homologue of vanadyl porphyrin C31 containing nine carbon atoms in the alkyl substituents.

Sulfuric Acid Assisted Extraction and Fractionation of Porphyrins From Heavy Petroleum Residuals With a High Content of Vanadium and Nickel

Primary porphyrin extracts were obtained from carbon tetrarchloride solutions of different heavy oil residuals with assistance of sulfuric acid. According to data of chromatographic separation of extracts porphyrinic fractions appear in amount of 13.0–24.2%. Based on UV/visible absorption spectroscopy the presence of porphyrins of etio and phyllo types mostly with rhodo and deoxophylloerythroetioporphyrins in lower amount was established. The content of porphyrins in obtained fractions was determined at the level of 15.3–44.8% of the total weight. It was shown that a higher concentration of porphyrins in sulfuric acid extracts occurs for the case of the high vanadium and nickel content and low amounts relation of asphaltenes to resins.

Structural-group composition and properties of heavy oil asphaltenes modified with sulfuric acid

ABSTRACT Details of the change of structural-group composition of heavy oil asphaltenes modified with sulfuric acid and oleum depending on the process conditions have been determined. The effect of the amount and concentration of sulfuric acid, exposure time, and elevated pressure has been evaluated. The formation of sulfo-, sulfono-, phenolic hydroxyl, carboxylic, and carbonyl functional groups has been detected in Fourier transform infrared (FTIR) spectra for the obtained sulfonated asphaltenes. Spectral coefficients have been calculated for asphaltenes and products of their sulfonation according to the main absorption bands in FT-IR spectra. Analysis of spectral coefficients has indicated the relationship of the fraction of newly formed functional groups in sulfonated asphaltenes and process conditions of sulfuric acid modification. The obtained sulfonated asphaltenes have been analyzed as sulfocationites with the evaluation of sorption capacity. It has been shown that the successive modification of heavy oil asphaltenes with sulfuric acid and oleum gives sulfocationite with the static exchange capacity of 3.39 meq/g. The relationship of spectral coefficients and sorption characteristics of sulfonated asphaltenes has been determined.

Thermal stability and sorption properties of asphaltene sulfocathionites

Abstract 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.

Distribution of vanadium and vanadyl porphyrins during fractionation of resins of heavy sulfurous oils

ABSTRACT Features of the content and distribution of vanadium and vanadyl porphyrins in the fractions of resins, which were obtained by separation using column chromatography on silica, have been studied on heavy sulfurous oils of various deposits of the Volga–Ural basin (Russia). The difference of the vanadium and vanadyl porphyrin contents in the fractions of oils of various production complexes has been shown. Features of structural–group composition and predominant types of vanadyl porphyrins in the fractions of resins have been determined.

Composition and sorption properties of asphaltene sulfonates

ABSTRACT The sulfonation of the dissolved oil objects by concentrated sulfuric acid was carried out at 60, 80, 100 oC and the resulting products with a structural-group composition similar to sulfonated asphaltenes were obtained. Structural-group composition of sulfonated oil products was established by Fourier transform infrared spectroscopy and the relative contents of sulfo-, sulfono- and carboxyl ionogenic functional groups was determined on the basis of spectral coefficients. The sorption capacity of sulfonated oil products (10-13 mg/g for Ca2+ and 14–18 mg/g for Cu2+) was determined by atom-absorption spectroscopy. It was established that the sorption characteristics of sulfonated oil products are determined by the total contents of asphaltene-resin components in starting oil objects and temperature of the sulfonation process.

Composition and Properties of Oxidation Products of Heavy Oil Resid Asphaltenes

Asphaltenes of various heavy oil resids are oxidized by aqueous sodium percarbonate solutions at 200°C and 4 MPa pressure. The composition and properties of the obtained products are analyzed. Water-soluble oxidation products in the asphaltene oxidation products comprise 47.4-49.4%. Products of oxidative condensation of asphaltenes enriched with hydroxyl, ether, and carboxyl groups dominate in the composition of water-insoluble oxidation products. The water-soluble oxidation products represent carboxylic acid concentrate. The characteristics of the structural-group composition of the obtained oxidation products are disclosed. The possibility of practical utilization of asphaltene oxidation products as adhesion additives to road asphalt and for removal of phenol from water is demonstrated.