Том 57, № 8 (2017)

Published data on the use of sulfur-containing molybdenum compounds as additives for lubricants used in modern technology are reviewed. Various types of sulfur-containing molybdenum compounds as friction modifiers have been considered, and aspects of their activity and mechanism of action have been discussed. The role of these additives as inhibitors of oxidation of hydrocarbon materials has been shown. The environmental problems of using heavy metal compounds in lubricant additive formulations are discussed. The results of recent studies on the use of nanosized molybdenum sulfide particles as friction modifiers are presented.

Biodegradation of high-viscosity oil of the Ashal’chinskoe field by indigenous microflora of soil on the basis of fen peat and humus with a high concentration of nutrients and microorganisms has been studied under laboratory conditions on model soil systems. It has been shown that after the adaptation period of ten days, the total population of heterotrophic bacteria increases by two orders of magnitude and the activity of soil enzymes increases by a factor of 2–3.5. Oil utilization was 84% over 180 days of the experiment. During this period of time, all petroleum hydrocarbons: alkanes, naphthenes, and arenes, are oxidized by 68–99%; the total biodegradation of resins and asphaltenes making 85.6 and 55.2%, respectively; i.e., the resins are oxidized easier that the asphaltenes. It has been found that the biotransformation of the high-molecular-weight hetero compounds resins and asphaltenes results in partial degradation of saturated structures and accumulation of oxygen in the composition of average molecules, with the average size of the block decreasing and naphthene structures partially degrading.

A series of ZrO₂–TiO₂–Al₂O₃ composite oxides with different Al₂O₃ ratios were prepared by coprecipitation method and used as the supports of Pt/NiO–MoO₃/ZrO₂–TiO₂–Al₂O₃ catalysts. Catalytic activities for n-decane cracking over these catalysts were evaluated under high temperature and high pressure conditions. Physicochemical characteristics of as-prepared catalysts were detected by using automatic adsorption instrument, X-ray diffractometer, temperature programmed reduction, and temperature programmed desorption techniques to characterize the catalysts and supports. The results indicated that the catalyst which contained 60 wt % Al₂O₃ had the largest surface area and pore volume (152.7 m²/g and 0.39 mL/g, respectively), and also it possessed strongest medium and strong acidity as well as medium acidic density. Moreover, the catalyst with 60 wt % Al₂O₃ exhibited better cracking performances compared with the others. The gas yields over Cat3 were 1.5 and 1.2 folds higher than that obtained from thermal cracking at 650 and 700°C, respectively. In addition, the heat sinks were improved 0.27 MJ/kg and 0.25 MJ/kg at 650 and 750°C, respectively.

Catalysts containing an MFI zeolite and an MFI/MCM-41 composite synthesized by the hydrothermal microwave method have been first studied in rapeseed oil hydroconversion. Catalysts provide the production of valuable petrochemicals, namely, high-octane components of motor fuels and С₂–С₄ olefins. Synthesized MFI zeolite mostly catalyzed the formation of aromatic hydrocarbons (ArH); incorporation of this zeolite into the matrix of mesoporous silicate MCM-41 leads to a decrease in the ArH content in the liquid hydrocarbon products owing to an increase in the yield of liquid aliphatic hydrocarbons. Promotion of the MFI zeolite synthesized by the hydrothermal microwave method with zinc ions leads to the formation of a catalyst providing the formation of liquid products consisting of ArH.

The physicochemical and catalytic properties of pyrolyzed cellulose-based Cu–Co solid dispersed composite catalysts synthesized by matrix isolation under the action of IR radiation have been studied. It has been shown that alcohols can be produced from CO and H₂ in the presence of the synthesized composite catalysts comprising Cu–Co solid dispersed phase nanoparticles. The effect of synthesis conditions on the structure of the composite catalysts and their activity in synthesis gas conversion to alcohols has been studied by X-ray diffraction analysis, ATR-FTIR spectroscopy, and in situ magnetometry.

The possibility of increasing the efficiency of utilization of spent motor oils as the dispersion medium of lubricating greases has been explored. It has been established that the removal of resins, asphaltenes, carbenes, and carboids from used mineral and synthetic motor oils makes it possible to obtain a base stock close to commercial base oils in the main characteristics. It has been proposed to use carbamide or monoethanolamine in a mixture with isopropanol. It has been found that more than 90% of the contaminants are removed from used engine oils by refining according to the methods proposed. The re-refined oils have a high margin of performance. The composition of Litol-24 and Solidol Zh grease analogues based on refined waste motor oils has been determined. The corrosion-preventing, adhesion, and strength properties of the lubricant compositions are considered. The results of bench testing of lubricant compositions in rolling bearings, which confirm their high performance properties, are presented.

Sulfur-, nitrogen-, and boron-modified alkylphenol additives for motor oils have been first produced by condensation of sulfurized alkylphenols with formaldehyde, alkanolamines, and boric acid followed by neutralization of the condensation products with calcium hydroxide. The structure of the resulting additives has been confirmed by IR spectroscopy. The functional properties of the additives in the composition of motor oils have been investigated. It has been found that they have high corrosion-preventing, antioxidant, and tribological properties and can be used as an additive for various motor oils. A lubricant composition M-14G₂ with high performance characteristics meeting the requirements of modern technology has been developed with the use of the additive IKhP-228.

The processing of discharge cutting fluids by membrane methods yields a concentrate consisting of petroleum products and surfactants. A gas chromatography–mass spectrometry study of the chemical composition has revealed the presence in the concentrate of dicyclohexylamine, which is a corrosion inhibitor according to published data. Therefore, it has been proposed to use the concentrate as a steel corrosion inhibitor for oilfield equipment. The physicochemical properties of the inhibitor have been determined, and corrosion tests for steel of Steel 20 grade have been carried out using the gravimetric method. To improve the protective properties of the inhibitor, the spent-coolant concentrate has been treated with a 1 M NaOH solution (to increase the pH) and modified by admixing oxypropylated diethylene glycol. According to the testing data, the degree of protection of Steel 20 was 78.5%. The resulting concentrate can be used as an inhibitor to protect pipelines against the corrosive effects of formation water. The composition of additives that can enhance the inhibitory characteristics of the concentrate has also been determined by testing.

Thermal transformations of hydrocarbons, resins, and a mixture of hydrocarbons and resins of heavy petroleum from the Usinskoe oilfield (Russia, Komi) have been studied. Data on the material balance of the process and the composition of gaseous and liquid products of thermolysis have been obtained. The structural characteristics of asphaltenes and resins resulting from thermolysis have been investigated, and changes in the hydrocarbon composition of the thermolysis products have been analyzed. It has been shown that the direction of thermal transformations of hydrocarbons changes in the presence of resins. During thermolysis, the resin degradation reactions facilitate the formation of hydrocarbons and polycondensation reactions give rise to asphaltenes.