In this work, a comparative study of the properties of polyethylene composites filled with the residue of solvent deasphalting of tar and asphaltenes isolated from it was carried out. Scanning electron microscopy analysis found that the compatibility of petroleum residue with the matrix was better than for asphaltenes. The observed effect was related to the present of petroleum resins, which have less polarity and long alkyl substituents that can improve molecular distribution asphaltenes in the nonpolar environment of polyethylene. Fourier transform infrared, thermo-gravimetric analysis, differential scanning calorimetry, and electron paramagnetic resonance methods have shown that asphaltenes play a key role in the thermal stabilization of composites. It is assumed that the radical traps in asphaltenes are free stable radicals, particles with unpaired electrons strongly delocalized on the pi-system of polyaromatic molecules. Their antiradical action was associated to interactions with radicals formed during the thermal and thermo-oxidative decomposition of polyethylene result in the recombination and inhibition of further free-radical destruction. An analysis of the properties showed that the addition of a petroleum residue to the polyethylene makes it possible to maintain good mechanical properties after thermal-oxidative aging of composites. Thus, such asphaltene concentrates can be recommended as promising fillers for polyolefins in the polymer industry.

Petroleum asphaltenes as well as their derivatives obtained by sulfonation are studied as model fillers in this work. There corresponding particle size (distribution), specific surface area, and elemental composition are described. It is found that the introduction of petroleum components into a polyethylene (PE) matrix improves its electret characteristics (for example, the surface charge density value for PE after 30 days of storage is reduced to 0.07 mu C/m(2), whereas PE compositions with asphaltenes reached 0.190 mu C/m(2) and samples with modified asphaltenes 0.382 mu C/m(2)). An increase in the number of sulfonic groups during the modification of asphaltenes leads to the creation of additional charge traps with even higher energies. This, in turn, leads to a significant (almost 2 times) improvement of the PE composites' electret characteristics. The best electret properties are obtained for a polyethylene composition with 7.5 wt.% sulfonated asphaltenes (SA). The introduction of asphaltenes and SAs increases the thermal stability of the PE electrets by increasing the thermal resistance of the polymer itself. It can be explained by the fact that asphaltenes are more resistant to thermal degradation, and SAs increase the thermal stability of polyethylene even more effectively. The obtained composites can be considered as model systems, as they provide a way to further enhance the thermal stability for polymers electret with traditional fillers by means of particles surface chemical modification.

Various types of surfactants (Tween 20, Tween 80, Span 20, and Span 80) were used as a stabilizing additive in composites based on petroleum asphaltenes and paraffin - a material that has prospects for use as a phase-transition material in thermal accumulators. The influence of surfactants on the structure and morphology of composites, the rheology of their melts, thermal conductivity, and crystallization ability is shown. An increase in thermal conductivity of 9% has been demonstrated. This correlates with the formation of filler clusters in the presence of surfactants. The presence of surfactants in composites with paraffin has a slight effect on the crystal lattice parameters of paraffin in composites, while the introduction of Tween 20 at a concentration of 1% wt. leads to an increase in the degree of crystallinity of paraffin. In melts of paraffin-asphaltene composites, the network of filler contacts contributes to the presence of a pronounced yield strength. The introduction of a surfactant leads to a decrease in the strength of the contact network and an increase in the fluidity of systems, probably due to the presence of surfactant adsorption layers on the surface of the contacting particles.

In this work, polyurethane composites with petroleum asphaltenes and their modified derivatives have been obtained and studied. The changes in the mechanical and thermal characteristics of polyurethane composites depending on the content of asphaltene fillers in concentrations of 1 and 2.5 wt% are shown. The distribution of native and modified asphaltenes in the polymer matrix was assessed using the X-ray power diffraction method. Composites with native asphaltenes and asphaltenes bearing amino groups showed the best performance in terms of distribution homogeneity in the matrix of polyurethane obtained from 2,4-toluylene diisocyanate (TDI) and polyethylene glycol adipate. It has been shown that the use of carboxylated (CA) and sulfonated (SA) asphaltenes in polyurethane composites leads to incomplete curing of the polymer. A significant decrease in the strength and elongation at break, as well as an increase in material hardness, was recorded for a composite containing 2.5 wt% of sulfonated asphaltene. The use of aminated asphaltenes makes it possible to increase the elongation at break due to additional interaction with TDI at the production of polyurethane composites. Composites with native and sulfonated asphaltenes showed the best thermal stability.

The reaction of 2-arylcyclopropane-1,1-dicarboxylates (ACDCs) with the unsaturated cyclohepta-2,4,6-triene-1-carboxylate system under the action of GaCl3 proceeds with a contraction of the seven-membered cycle and formally corresponds to the [2+4] or [3+2] cycloaddition of 1,2- or 1,3-zwitterionic intermediates generated from ACDCs to the double bonds of the norcaradiene structure. On the contrary, cycloheptatrienes with donor substituents practically do not form cycloaddition products in reactions with 1,2-zwitterionic intermediates, but undergo dehydrogenation and significant oligomerization. Methyl- and phenylcycloheptatriene turned out to be rather good precursors of hydride ions, which resulted in the formation of (2-phenylethyl)malonate, while 7-methoxycycloheptatriene predominantly transforms the 1,2-zwitterion open form to the initial ACDC.

A new type of dimerization of dimethyl (β-styryl)malonates in the presence of TiCl4 accompanied by elimination of a methanol molecule was discovered. Selective methods for the synthesis of substituted trimethyl 4-hydroxy-[1,1′-biaryl]-3,3,5(2H)-tricarboxylates and trimethyl 7-hydroxy-9,10-dihydro-5,9-methanobenzo[8]annulene-6,8,8(5H)-tricarboxylates were developed. The regularities of the occurring processes were determined and a similar reaction of β-styrylmalonate with benzylidenemalonate in the presence of TiCl4 was performed in the scope of the suggested mechanism.

Acidic and basic ion‑exchange resins were prepared by chemical modification of petroleum asphaltenes. The resulting products were characterized by IR spectroscopy and MALDI mass spectrometry. Feasibility was demonstrated for carrying out catalytic acylation of salicylic acid in the presence of acidic and basic catalysts derived from petroleum asphaltenes to give acetylsalicylic acid. Asphaltene‑derived ion‑exchange resins containing either sulfonic acid (SA) or amino groups (AA) were used as catalysts. These catalyzed reactions gave acetylsalicylic acid in 78

Ethylene tar is the main byproduct of ethylene synthesis obtained via pyrolysis of hydrocarbon feedstock. With the growing demand for ethylene, the efficient use of ethylene tar is of great importance from both an economic and an ecological point of view. It contains significant amounts of polycyclic aromatic hydrocarbons, which can be designated as technogenic asphaltenes. Such polyaromatic structures can be isolated and used as a synthetic platform for modification and molecular engineering, similar to petroleum asphaltenes. In this study, the possibility of modifying technogenic asphaltenes by oxidizing reagents used previously for petroleum asphaltenes was shown for the first time. Technogenic asphaltenes contain significantly fewer heteroatomic structures and have a lower molecular weight compared to petroleum asphaltenes. The compositional features of technogenic asphaltenes ensure deeper oxidation with the formation of various O-containing products, whose properties can vary significantly depending on the reaction conditions. At the same time, the general patterns of oxidative modification of technogenic asphaltenes correspond to the oxidation processes of petroleum asphaltenes. The modification products obtained in this way can be used as sorbents, catalysts, fillers for polymers, adhesive additives for road bitumens, etc.

The low thermal conductivity of paraffin and other organic phase change materials limits their use in thermal energy storage devices. The introduction of components with a high thermal conductivity such as graphene into these materials leads to an increase in their thermal conductivity. In this work, we studied the use of inexpensive carbon fillers containing a polycyclic aromatic core, due to them having a structural similarity with graphene, to increase the thermal conductivity of paraffin. As such fillers, technogenic asphaltenes isolated from ethylene tar and their modified derivatives were used. It is shown that the optimal concentration of carbon fillers in the paraffin composite, which contributes to the formation of a structural framework and resistance to sedimentation, is 5 and 30 wt. %, while intermediate concentrations are ineffective, apparently due to the formation of large aggregates, the concentration of which is insufficient to form a strong framework. It has been found that the addition of asphaltenes modified with ammonium persulfate in acetic acid significantly increases the thermal conductivity of paraffin by up to 72%.

A series of heavy oil (HO) thermolysis experiments in the presence of 2.5-10.0% maltene fraction recovered from oil has been performed. It has been shown that addition of maltene fraction provides HO conversion during thermolysis and a decrease in the viscosity of the products. An increase in the concentration of additive results in the decrease in coke content in the products as compared to reference experiment. Thermolysis conditions of HO of Ashal'chinskoe deposit (Russia), which give liquid products possessing viscosity of nearly 100 mm(2)/s in more than 97% yield in the presence of 5.0 and 10.0% of maltene fraction, have been determined, namely, 415 degrees C and 30 atm in flow reactor.

The products from the reaction of petroleum asphaltenes with sulfuric acid under various conditions, accompanied by oxidation, sulfonation, and decomposition reactions, were studied. The change in the content of stable free radicals and vanadyl complexes in the products from the reaction of asphaltenes with sulfuric acid in relation to the time and temperature was determined by EPR spectroscopy. The chemical processes in the reaction of asphaltenes with sulfuric acid take place most strongly in the first hour, being accompanied by peak growth of the concentration of stable free radicals. With increase in the length of treatment of the asphaltenes with sulfuric acid there is a decrease in the concentration of stable free radicals accompanied by a decrease in the content of sulfo groups in the products. After only 30 min of the process there was a marked decrease in the content of vanadyl complexes in the reaction products.

Stepwise oxidation-sulfonation of vacuum residue asphaltenes was carried out. It was shown that oxidation leads to the formation of carboxyl groups around the perimeter of the polyaromatic core. By contrast to ammonium persulfate, potassium dichromate oxidizes to a greater extent the sulfur atoms in the composition of asphaltenes which undergo desulfurization in an acidic medium. In the oxidation-sulfonation products the C/H parameter increases by a factor of 2.1, and the O/C parameter, by a factor of 19. The reaction of sulfonation of the oxidized asphaltenes proceeds less efficiently than that of the initial asphaltenes, as expressed in the value of the total static exchange capacity. Complexes of the oxidation-sulfonation products of asphaltenes with divalent copper cations were converted to redox ion-exchange materials by subsequent reduction with sodium dithionite in an alkaline medium.

The work is devoted to evaluation of the thermal conductivity of composites based on asphaltenes and paraffin as a phase change material. Asphaltenes with different structural characteristics, obtained by chemical modification and fractionation were used to improve the heat conductivity of paraffin. Modification of asphaltenes with sulfuric acid and oleum made it possible to obtain samples with increased content of condensed structure fragments and minimum content of aliphatic ones. The form of modified asphaltenes neutralized with diethanolamine was also investigated. Asphaltene molecules with increased aliphatic content were isolated by fractionation with toluene / acetone mixtures. Structural, thermophysical and rheological properties of composites based on paraffin and these types of asphaltenes are analyzed. It is shown that the introduction of asphaltenes into the paraffin matrix does not violate its ability to crystallize, but leads to a decrease in the degree of crystallinity and an increase in the crystallization temperature. The increased content of the condensed structures in modified asphaltenes leads to strong agglomeration, and as a result, to a decrease in the thermal conductivity of the composite material at room temperature. The introduction of asphaltenes with high aliphatic fragments content ensures their more uniform distribution in the paraffin matrix, which contributes to an increase in the thermal conductivity of the system.

This article presents data on electron paramagnetic resonance (EPR) and mass spectrometric analysis of potato tubers, irradiated with gamma rays, in order to examine and identify changes in the molecular composition of organic matter following radiation exposure. The products of the Maillard reaction were compared with the products of intramolecular radiolysis of organic constituents of potatoes. The presence of free radicals was verified using EPR. DDPM (2,3-dihydro-3,5-dihydroxy-6-methyl-4 (H)-pyran-4-one) was among the radiolysis products detected via mass spectrometry, which points to the intramolecular dehydration of potato carbohy-drates. EPR signals indicate single-electron transitions of the semidione radical anionic molecular compounds. It has been shown that irradiation with gamma rays significantly destroys the carbohydrate, lipid, keto-carotene and amino acid molecules of potatoes.

Strongly acidic cation exchangers were obtained by the sulfonation and successive sulfonation and nitration of petroleum asphaltenes. The cation exchangers were characterized by IR spectroscopy and acid–base back titration; the surface morphology was studied by scanning electron microscopy. The kinetic regularities of the Kabachnik–Fields reaction were studied at various temperatures in the course of catalysis by the cation exchangers based on asphaltenes and in the absence of a catalyst.

The literature data on the abiotic degradation of asphaltenes are the subject of a systematic review. Such degradation may proceed under natural conditions. In particular, the action of sunlight, especially, ultraviolet radiation, initiates photolysis and photooxidation in asphaltenes leading to an increase in their oxygen content, thereby shifting the hydrophilic-lipophilic balance toward hydrophilicity and increased access of the reaction products for subsequent biotic degradation by microorganisms. The action of ionizing radiation does not lead to a significant change in the molecular composition of asphaltenes since they are highly inert to radiation. An exception is found for the irradiation of asphaltenes by intense electron beams, leading to their considerable degradation.

This review is devoted to the generalization and systematization of the available literature data on the processes of abiotic degradation of asphaltenes, which can occur in natural conditions. In particular, it was shown that exposure to sunlight, and especially UV radiation, triggers photolysis and photooxidation reactions in asphaltenes, leading to an increase in the oxygen content in them, thereby shifting the hydrophilic-lipophilic balance towards hydrophilicity. At the same time the availability of reaction products for subsequent biotic degradation by microorganisms is increased. Exposure to ionizing radiation does not lead to a significant change in the molecular composition of asphaltenes, due to their high radiation resistance. As exception there is the irradiation of asphaltenes with intense electron beams, which leads to their significant degradation.

The sorption properties of native and modified petroleum asphaltenes with respect to phenol were studied under static conditions. The asphaltenes were modified by nitration, followed by reduction with sodium sulfide. Sorption isotherms of phenol were constructed on the basis of the obtained data, and equations for the adsorption processes were calculated. It was found that the adsorption isotherms can be described most accurately by the Freundlich and Langmuir equations. It was found that the process occurs as a result of physical adsorption.

The sorption properties of native and modified petroleum asphaltenes with respect to phenol have been studied under static conditions. Modification of asphaltenes was carried out by nitration, followed by reduction with sodium sulfide. Based on the data obtained, phenol sorption isotherms were constructed and the equations for the adsorption processes were calculated. It was found that the adsorption isotherms can be described most correctly by the Freundlich and Langmuir equations. It was revealed that the process is carried out due to physical adsorption.

Novel anion-exchange resins were prepared from asphaltenes by nitration with nitric acid followed by reduction of the nitrated asphaltenes with sodium sulfide. The aminated asphaltenes were investigated as anion exchange resins for the treatment of phenol-containing wastewater. Their maximum adsorption capacity was found to be 2.3-fold superior to that of an industrial AV-17-8 (OH– form) AER sample.