In this work, a series of thiosemicarbazones with phenol fragments were used as starting compounds for the synthesis of new effective antioxidants containing both a phenol substituent and a heterocyclic fragment: thiazole and thiazolidinone. To determine the most stable conformation of thiosemicarbazone, a potential energy scan was used, along with NOESY NMR spectroscopy data. A number of thiazole derivatives were obtained due the interaction of thiosemicarbazones with several bromoketones: bromoacetophenone, bromodimedone, and bromoacetylcoumarin. The product yields varied from 71 to 94%. Thiazolidinone derivatives were obtained through the reaction between thiosemicarbazones and chloroacetic acid or maleic anhydride with good yields of 82–95%. The antioxidant activities of all the products were determined in vitro: the radical cation scavenging activity was estimated using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate), while the ferric reducing capacity was determined using the ferricyanide/Prussian blue method. It was found that the antioxidant activity of most synthesized substances in both tests exceeds the activity of 4-methyl-2,6-di-tert-butylphenol, while derivatives with a fragment of 2,6-di-tert-butylphenol have the highest activity.

A series of benzotriazole, cyclic amides and pyrimidine derivatives, containing 2,6-di-tert-butyl-phenol fragments, were synthesized. The redox properties of obtained compounds were studied using the cyclic voltammetry on a platinum electrode in acetonitrile. The oxidation potentials of all substances were comparable to those of BHT. The obtained compounds were tested for their antibacterial activity, and N-(2-(3,5-di-tert-butyl-4-hydroxyphenyl)-2-oxoethyl)isatin (32 μg/mL) exerted good activity against Staphylococcus aureus.

The influence of different groups of diesel hydrocarbons on the physicochemical properties and performance characteristics of diesel fuels has been considered. The parameters to be evaluated have been cetane number, cetane index, diesel index, pour point, and cold filter plugging point. It has been shown that the hydrocarbon group composition, which reflects only the amount of arenes and paraffinic-naphthenic hydrocarbons, gives insufficient information for prediction of the performance properties of fuels. A more detailed study of the hydrocarbon composition of each group of compounds—the ratio of mono-, bi-, polycyclic arenes, the concentration and the ratio of high- and low-melting-point n-alkanes and isoalkanes—has made it possible to reveal the influence of each group on individual fuel characteristics.

Alkenyl succinimides with different alkyl chain lengths have been synthesized. Alkenyl succinimide samples based on polyisobutylene with molecular weights of 1000 and 1300 have displayed the best functional properties. By differential thermal analysis, it has been shown that these samples have high thermal stability and do not decompose at temperatures of about 300°C. Two representative samples of polyalkenyl succinimides in the composition of blended gasoline have been subjected to bench testing in a full-sized engine. A significant reduction in deposits on the engine intake valves has been noted upon testing the fuel in the presence of the synthesized samples with a concentration of 0.05 wt %.

The chemical composition of crude oils from five fields of Volgograd oblast has been studied. It has been shown that predicting the low-temperature properties of oil and for selecting asphaltene-resin-paraffin deposition inhibitors requires a more profound knowledge of the hydrocarbon composition of oil in addition to the structural-group composition. The presence of produced water in the produced well fluid increases the amount of asphaltene-resin-paraffin deposits.