One of the valuable fractions of paraffinic oils is the diesel fraction, which can be used as a commercial fuel. However, the high content of alkanes of normal structure (~10–40%) in the diesel fraction leads to a deterioration in the performance characteristics of the fuel and, as a result, the inability to use the diesel fraction without additional processing in the cold season at lower temperatures, which is critical for many regions with cold winters. The process of catalytic dewaxing is one of the most promising ways to improve the low-temperature characteristics of diesel fractions. This work is devoted to studying the activity of promoted Ni, Mo, and Ni-Mo catalysts based on mesoporous aluminosilicate and pre-activated bentonite in dewaxing diesel fractions. The effect of the nature and content of promoting additives on the activity of bifunctional catalysts in the process of hydroisodewaxing of diesel fraction in a flow-type reactor in the temperature range of 260–340 °C, pressure of 2 MPa and feed space velocity of 1 h^–1 was studied. It is shown that the synthesized bifunctional catalysts based on mesoporous aluminosilicate and pre-activated bentonite from the Tagan field (Ni/MAS-H-bentonite, Mo/MAS-H-bentonite, and Ni-Mo/MAS-H-bentonite) have the necessary balance of Lewis and Bronsted acid centers strengths. It allows them to selectively conduct the hydroisodewaxing process. It has been established that the use of the synthesized 5% Ni-1% Mo/MAS-H-bentonite bifunctional catalyst in the diesel fractions hydroisodewaxing process under optimal process conditions makes it possible to obtain diesel fuel with low-temperature characteristics that meet the requirements for cold climate fuels: cold filter plugging point (CFPP)—minus 33 °C, flash point in a closed cup—39 °C and pour point—minus 36 °C.

The limitation on the content of aromatic hydrocarbons and sulfur is associated with environmental requirements according to Euro-5 standards. Upon combustion, these substances release highly toxic compounds into the atmosphere, adversely affecting human health and the surrounding environment. Additionally, a high concentration of aromatic hydrocarbons in diesel fuel significantly degrades its quality, leading to soot formation and reducing its cetane number. According to Euro-5 standards, the content of polycyclic aromatic hydrocarbons and sulfur compounds should not exceed 8% and 10 mg/kg, respectively. To address the challenge of producing high-quality diesel fuels, the hydrotreatment process is employed in the presence of heterogeneous catalysts.The article presents the synthesis of mesoporous aluminosilicates and bifunctional catalysts based on them to study the activity of the hydrotreatment process for a model mixture. The obtained samples were investigated using various physico-chemical methods such as SEM, low-temperature nitrogen adsorption/desorption, XRD, and FT-IR. It was established that the Ni/MAS-H-bentonite and Mo/MAS-H-bentonite catalysts exhibit high activity and selectivity in the hydrotreatment process under optimal conditions (240°C, 3 MPa, and 0.5 h^-1).

In the article, the synthesis of mesoporous aluminosilicates was carried out according to the developed methods, in which tetraethylorthosilicate Si(OC2H5)4 was used as a source of silicon, secondary aluminum butoxide (sec-BuO)3Al and aluminum triisopropoxide Al(i-OPr)3 were used as aluminum's sources. The synthesis of mesostructured aluminosilicate is based on the method of copolycondensation of silicon and aluminum sources in the presence of alcohol. Hexadecylamine (HDA, C16H33NH2) was used as a template for the formation of a porous structure. The physicochemical characteristics of the synthesized structured mesoporous aluminosilicates have been studied. It was found that the synthesized materials MAS-1 and MAS-2 possess high specific surface area from 511 to 1170.0 m2/g. The presence of a mesoporous and ordered structure in the synthesized aluminosilicates is confirmed by the data of low-temperature nitrogen adsorption/desorption, X-ray diffraction and FT-IR. To determine the relative strength of Brønsted and Lewis acid sites on the surface of mesoporous aluminosilicates, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) of adsorbed pyridine samples was carried out. DRIFT analysis data demonstrated a majority of Lewis acid sites on the surface of the synthesized materials. We are currently studying the possibility of applying these materials as acidic components of bifunctional catalysts for petrochemical N E W S OF THE NATIONAL ACADEMY OF SCIENCES OF THE REPUBLIC OF KAZAKHSTAN SERIES CHEMISTRY AND TECHNOLOGY ISSN 2224-5286 https://doi.org/10.32014/2020.2518-1491.94 Volume 6, Number 444 (2020), 22 – 29 UDC 665.64.097.3 MRNTI 61.51.17, 61.51.19 К.M. Umbetkaliyeva1,2, G.K. Vassilina1,2, А.К. Abdrassilova1 , А.R. Khaiyrgeldinova2, Т.К. Vassilina2,3, Zh.Y. Zakirov1, М.Kh. Taliyeva2 , А.К. Kaldybayeva2 1al-Farabi Kazakh National University, Almaty, Kazakhstan; 2SRIfor New Chemical Technologies and Materials, Almaty, Kazakhstan; 3Кazakh National Agrarian University, Almaty, Kazakhstan. E-mail: kamilla.u.m21@mail.ru, v_gulzira@mail.ru, albina06.07@mail.ru, asyltas_2008@mail.ru, v_tursunai@mail.ru, abuzhassulan@gmail.com, taliyevamadina@gmail.com, kaldybayeva.assylai@gmail.com SYNTHESIS AND PHYSICOCHEMICAL CHARACTERISTICS OF MESOPOROUS ALUMINOSILICATES In the article, the synthesis of mesoporous aluminosilicates was carried out according to the developed methods, in which tetraethylorthosilicate Si(OC2H5)4 was used as a source of silicon, secondary aluminum butoxide (sec-BuO)3Al and aluminum triisopropoxide Al(i-OPr)3 were used as aluminum's sources. The synthesis of mesostructured aluminosilicate is based on the method of copolycondensation of silicon and aluminum sources in the presence of alcohol. Hexadecylamine (HDA, C16H33NH2) was used as a template for the formation of a porous structure. The physicochemical characteristics of the synthesized structured mesoporous aluminosilicates have been studied. It was found that the synthesized materials MAS-1 and MAS-2 possess high specific surface area from 511 to 1170.0 m2/g. The presence of a mesoporous and ordered structure in the synthesized aluminosilicates is confirmed by the data of low-temperature nitrogen adsorption/desorption, X-ray diffraction and FT-IR. To determine the relative strength of Brønsted and Lewis acid sites on the surface of mesoporous aluminosilicates, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) of adsorbed pyridine samples was carried out. DRIFT analysis data demonstrated a majority of Lewis acid sites on the surface of the synthesized materials. We are currently studying the possibility of applying these materials as acidic components of bifunctional catalysts for petrochemical processes.

Высокопарафинистые нефти характеризуются ухудшением реологических и низкотемпературных свойств вследствие кристаллизации парафинов при охлаждении. Это приводит к повышению вязкости, снижению текучести и осложнению безопасной транспортировки нефти по промышленным трубопроводным системам. В связи с этим разработка эффективных полимерных депрессорных присадок и установление взаимосвязи между их составом и функциональными свойствами являются актуальными задачами современной нефтедобывающей отрасли. Цель исследования заключалась в изучении влияния исходного мольного соотношения октадецилметакрилата (ОДМА) и малеинового ангидрида (МА) на реологические свойства нефти, определении оптимального состава сополимера и оценке влияния его последующей химической модификации. Сополимеры ОДМА–МА синтезировали методом радикальной сополимеризации при исходных мольных соотношениях мономеров ОДМА:МА 1:1, 2:1, 3:1 и 4:1. Наиболее эффективный сополимер модифицировали октадеканолом и октадециламином. Полученные материалы исследовали методами ИК-Фурье-спектроскопии, эксклюзионной хроматографии, вискозиметрии и реометрии. Влияние полученных сополимеров на реологические свойства высокопарафинистой нефти месторождения Акшабулак оценивали при концентрации присадки 750 ppm. Сополимер с исходным мольным соотношением ОДМА:МА = 3:1 (ОМ-3) продемонстрировал наибольшую эффективность, снизив кажущуюся вязкость нефти при 10 °C с 0,087 до 0,025 Па·с. Для ОМ-3-ОД и ОМ-3-ОДА соответствующие значения составили 0,031 и 0,045 Па·с. ОМ-3 и ОМ-3-ОДА снизили температуру застывания нефти с 9 до 3 °C, тогда как ОМ3-ОД — до 6 °C. Практическая значимость работы заключается в возможности использования сополимера ОДМА–МА с исходным мольным соотношением ОДМА:МА = 3:1 в качестве перспективной основы для разработки депрессорных присадок, улучшающих низкотемпературную текучесть и транспортные характеристики высокопарафинистых нефтей.

This study investigates the effect of dibenzothiophene on the hydrogenation of aromatic hydrocarbons over bifunctional catalysts based on mesoporous Al-HMS aluminosilicates. Mesoporous aluminosilicate materials with different Si/Al ratios varying from 10 to 70 were synthesized and employed as supports for Ni-Mo-Al-HMS-H-bentonite catalysts. The physico-chemical features of the materials were characterized using ICP-OES, nitrogen physisorption at low temperatures, XRD, FTIR, and pyridine adsorption FTIR spectroscopy. Catalytic activity was evaluated in the hydrogenation of a model mixture of 2-methylnaphthalene and n-hexadecane at temperatures between 220-300°C and at 6 MPa H2. The optimal catalytic performance was observed for the sample with a Si/Al ratio of 10, displaying high conversion and selectivity to 2-methyldecalin as a result of sufficient Brønsted and Lewis acidity. The presence of dibenzothiophene leads to a decrease in conversion and selectivity due to sulfur-induced catalyst poisoning and shifts the optimal reaction temperature from 240 to 260°C. These findings highlight the important role of acid properties of mesoporous aluminosilicates in hydrogenation and hydrotreatment processes of aromatic compounds.