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.

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.

В работе изучена возможность протекания каталитической реакции циклизации гидразин гидрата и акриловой кислоты при комнатной температуре в присутствии кислотного катализатора на основе нефтяных асфальтенов. Изучено влияние сульфокатионита на возможность получения целевого пиразолидина-3-она. Проанализированы реакционные массы и их кубовые остатки. Методом газовой хромато-масс-спектрометрии и путем ионизации электроспреем установлены различные индивидуальные, олигомерные и полимерные продукты. Предложены наиболее вероятные структуры полученных продуктов.

The possibility of the catalytic cyclization reaction between hydrazine hydrate and acrylic acid at room temperature on an acid catalyst based on petroleum asphaltenes was studied. The effect of sulfocationite on the possibility of obtaining the target pyrazolidine-3-one was investigated. The reaction mixtures and their bottoms are analyzed. Different oligomeric and polymeric products were identified by gas chromatography-mass spectrometry and electrospray ionization. The most probable structures of the resulting products were described.

The products resulting from the oxidative modification of petroleum asphaltenes were studied by Raman spectroscopy. Oxidizing agents such as peroxyacetic acid, potassium dichromate, and ammonium persulfate were used. Raman spectroscopy data indicated that the diameter of the aromatic sheets in asphaltenes varies widely depending on the calculation method applied. During chemical modification, the number of aromatic sheets decreases by several folds compared to native asphaltenes. The average number of aromatic rings per asphaltene sheet was found to be 8–10.