Physical and Theoretical Chemistry, Catalysis, Process Chemistry and Technology, Modeling and Simulation
12
Scopus Publications
Scopus Publications
The Role Metals of Second and 12th Group in the Oxidation of Ethylbenzene Nikolai V. Ulitin, Ildar N. Zalyaliev, Nikolai A. Novikov, Yana L. Lyulinskaya, Konstantin A. Tereshchenko, Daria A. Shiyan, Natalia M. Nurullina, Svetlana N. Tuntseva, Tatyana L. Puchkova, Viktoriya I. Anisimova, Galina G. Elimanova, Kharlampii E. Kharlampidi International Journal of Chemical Kinetics, 2026 A kinetic model of ethylbenzene oxidation by air oxygen in the presence of 2‐ethylhexanoates of metals of the second and 12th groups (Mg, Ca, Sr, Ba, Zn, and Cd) as catalysts was constructed and parameterized using experimental data. Using the model, it is shown that: (1) in the range of 1–100 mmol/L, there exist initial concentrations of catalysts below which an increase in the initial catalyst concentration leads to an increase in the rate of ethylbenzene hydroperoxide formation in the oxidation of ethylbenzene (428 K, 1 atm, volume flow rate of air supply to the reactor of 0.018 m 3 /h, initial ethylbenzene concentration of 8.17 mol/L, initial concentrations of other species are 0), and above which it leads to a decrease (2‐ethylhexanoates of Mg, Ca, and Zn) or a plateau (2‐ethylhexanoates of Sr, Ba, and Cd); this is because the catalysts simultaneously accelerate the reactions of both formation and decomposition of ethylbenzene hydroperoxide, and starting from a certain initial catalyst concentration, the decomposition of ethylbenzene hydroperoxide begins to prevail over its formation; (2) the key reaction for the formation of ethylbenzene hydroperoxide and for ethylbenzene conversion in catalytic ethylbenzene oxidation, as in the non‐catalytic process, is the reaction between ethylbenzene and the peroxyl radical of ethylbenzene; the key reactions governing selectivity are the formation of methylphenylcarbinol and acetophenone from oxyl and peroxyl radicals of ethylbenzene; the role of the catalyst is to increase the concentrations of these radicals through the decomposition reactions of the intermediate adduct “ethylbenzene hydroperoxide + catalyst”; (3) Mg, Ca, Sr, Cd 2‐ethylhexanoates deactivate within 1 h of the ethylbenzene oxidation process, while Ba and Zn 2‐ethylhexanoates deactivate within 4 h (428 K, 1 atm, volume flow rate of air supply to the reactor of 0.018 m 3 /h, initial ethylbenzene, ethylbenzene hydroperoxide, and catalyst concentrations of 8.163, 0.022, and 5 mmol/L, respectively, initial concentrations of other species are 0); therefore, these catalysts should not affect the subsequent transformations of ethylbenzene hydroperoxide during propylene epoxidation in the Halcon process.
Catalytic Effect of Dibenzo-18-Crown-6 Ether Complexes With Group 2 Metal Chlorides on the Kinetics of Ethylbenzene Oxidation Ildar N. Zalyaliev, Nikolai V. Ulitin, Yana L. Lyulinskaya, Konstantin A. Tereshchenko, Natalia M. Nurullina, Svetlana N. Tuntseva, Tatyana L. Puchkova, Kharlampii E. Kharlampidi International Journal of Chemical Kinetics, 2026 A kinetic model of ethylbenzene oxidation catalyzed by dibenzo‐18‐crown‐6 ether complexes with group 2 metal chlorides (Ca, Sr, Ba) was developed and parameterized using experimental data. Kinetic modeling demonstrated that: 1) an increase in the initial catalyst concentration from 1 to 100 mmol/L leads to a monotonic increase in the rate of ethylbenzene hydroperoxide formation (428 K, 1 atm, volume flow rate of air supply to the reactor of 0.018 m3/h, initial ethylbenzene concentration of 8.17 mol/L, initial concentrations of other species are 0), indicating that the formation of ethylbenzene hydroperoxide prevails over its decomposition; 2) catalysts deactivate within 1 h of the ethylbenzene oxidation process; thus, they are not affect subsequent transformations of ethylbenzene hydroperoxide during propylene epoxidation via the Halcon process; 3) among the dibenzo‐18‐crown‐6 ether complexes with group 2 metal chlorides, the complex with Ca chloride at an initial concentration of 5 mmol/L should be recognized as the best catalyst for industrial use (428 K, 1 atm, volume flow rate of air supply to the reactor of 0.018 m3/h, initial ethylbenzene concentration of 8.17 mol/L, initial concentrations of other species are 0), because it provides the same selectivity as that achieved in non‐catalytic ethylbenzene oxidation (about 80%) and reduces the time to reach 10% ethylbenzene conversion by a factor of three (from 1.5 h in the non‐catalytic process to 0.5 h in the catalytic process).
Effect of Monomer Mixture Composition on TiCl4-Al(i-C4H9)3 Catalytic System Activity in Butadiene–Isoprene Copolymerization: A Theoretical Study Konstantin A. Tereshchenko, Rustem T. Ismagilov, Nikolai V. Ulitin, Yana L. Lyulinskaya, Alexander S. Novikov Computation, 2025 Divinylisoprene rubber, a copolymer of butadiene and isoprene, is used as raw material for rubber technical products, combining isoprene rubber’s elasticity and butadiene rubber’s wear resistance. These properties depend quantitatively on the copolymer composition, which depends on the kinetics of its synthesis. This work aims to theoretically describe how the monomer mixture composition in the butadiene–isoprene copolymerization affects the activity of the TiCl4-Al(i-C4H9)3 catalytic system (expressed by active sites concentration) via kinetic modeling. This enables development of a reliable kinetic model for divinylisoprene rubber synthesis, predicting reaction rate, molecular weight, and composition, applicable to reactor design and process intensification. Active sites concentrations were calculated from experimental copolymerization rates and known chain propagation constants for various monomer compositions. Kinetic equations for active sites formation were based on mass-action law and Langmuir monomolecular adsorption theory. An analytical equation relating active sites concentration to monomer composition was derived, analyzed, and optimized with experimental data. The results show that monomer composition’s influence on active sites concentration is well described by a two-step kinetic model (physical adsorption followed by Ti–C bond formation), accounting for competitive adsorption: isoprene adsorbs more readily, while butadiene forms more stable active sites.
A Hybrid Approach to Predicting Glass Transition Temperatures of Organic Homopolymers: A Combination of the QSPR Model and the Increment Method G. R. Shadrina, V. I. Anisimova, I. S. Rodionov, A. A. Baldinov, N. V. Ulitin, Ya. L. Lyulinskaya, K. A. Tereshchenko, D. A. Shiyan Doklady Physical Chemistry, 2025 Abstract In recent years, machine learning algorithms have become popular for predicting the physicochemical properties of polymers, including the glass transition temperature (Tg). Accurate Tg prediction is critical for developing polymers with desired properties. Traditional Tg prediction was based on semi-empirical methods, such as Askadskii’s method. The goal of this study was to develop a hybrid approach for predicting the Tg of organic homopolymers, combining Askadskii’s method and the QSPR model with machine learning (ML), which uses the advantages of theoretical analysis and the capabilities of ML to improve prediction accuracy. Random Forest, K-Nearest Neighbors, and a multilayer perceptron were used. The molecular structure of the polymers was represented by structural keys (MACCSKeys) and Morgan fingerprints. Optimization of the random forest algorithm hyperparameters enabled an R2 of up to 0.77 to be achieved on the test set. A comparative analysis showed that Morgan fingerprints that consider the spatial arrangement of fragments provide higher prediction accuracy, especially for isomeric homopolymers, where the spatial arrangement of substituents is important. The results demonstrate the potential of using ML for predicting polymer Tg based on glass transition theories and highlight the need for further research into hybrid models.
Interpretation of the Structure–Glass Transition Temperature Relationship for Organic Homopolymers with the Use of Increment, Random Forest, and Density Functional Theory Methods N. V. Ulitin, G. R. Shadrina, V. I. Anisimova, I. S. Rodionov, A. A. Baldinov, Ya. L. Lyulinskaya, K. A. Tereshchenko, D. A. Shiyan Journal of Structural Chemistry, 2025 Abstract The prediction of structural glass transition temperatures (Tg) of organic homopolymers is considered using the increment method and the quantitative structure–property relationship (QSPR) model based on the random forest algorithm. The increment method enables the calculation of the polymer glass transition temperature based on the monomer link structure: Tg = A/(B + C). The QSPR model demonstrates the accuracy of predicting Tg through parameters A, B, and C - R2 = 0.85. To interpret the physical meaning of A, B, and C parameters their correlation with quantum chemical descriptors is analyzed. A characterizes the Van der Waals volume of the repeating link of the organic homopolymer and weak intermolecular interactions. B shows a significant correlation with the electronic properties of monomer links of polymers, which indicates its relationship with both weak and strong intermolecular interactions. C characterizes the molecular packing coefficient and demonstrates the inverse dependence on the B parameter.
Kinetics of Methyl Methacrylate Polymerization in the Presence of Initiating Systems “Peroxide + Zirconocene Dichloride” When the Methyl Methacrylate Adhesive is Cured Konstantin A. Tereshchenko, Daria A. Shiyan, Andrey A. Osipov, Vera P. Bondarenko, Nikolai V. Ulitin, Elina M. Sabitova, Anton V. Bekker, Yana L. Lyulinskaya, Nikolay A. Novikov, Natalia M. Nurullina, Svetlana N. Tuntseva, Tatyana L. Puchkova, Yaroslav O. Mezhuev, Kharlampii E. Kharlampidi, Sergey V. Kolesov Industrial and Engineering Chemistry Research, 2024 A kinetic model of the curing of methyl methacrylate adhesive (including nanocomposite methyl methacrylate adhesive) in the presence of the initiating systems “aryl peroxide + zirconocene dichloride” and “aryl hydroperoxide + zirconocene dichloride” is made. Computational experiments have been carried out which demonstrate the relationship of the curing rate with the curing temperature in the range of 323–343 K and with the ratio of the initial concentration of zirconocene dichloride to the initial concentration of the initiator [Mc] 0 /[ I ] 0 for the following initiators: benzoyl peroxide (PB), ethylbenzene hydroperoxide (HPEB), and ethylbenzene hydroperoxide adduct with cadmium 2-ethyl hexanoate [HPEB·Cd(EH) 2 ]. It is shown that in order to increase the curing rate of the adhesive, curing should be carried out at a higher temperature (343 K) and at a higher value of the ratio [Mc] 0 /[ I ] 0 = 10 in the presence of the most rapidly decomposing initiator HPEB·Cd(EH) 2 . To increase the weight-average molecular weight of poly(methyl methacrylate), the proportion of syndiotactic triads in its composition, and consequently, to improve the adhesion strength and heat resistance of the adhesive joint, the curing of the adhesive must be carried out at the reduced temperature (323 K) and the reduced ratio of the [Mc] 0 /[ I ] 0 = 0.1 in the presence of the least rapidly decomposing initiator HPEB.
Mechanism of Cumene Oxidation into Cumene Hydroperoxide (Curing Initiator for Acrylic Adhesives) in the Presence of Ca, Sr, Ba Chloride Complex with Dibenzo-18-Crown-6 Ether N. A. Novikov, N. V. Ulitin, Ya. L. Lyulinskaya, D. A. Shiyan, K. A. Tereshchenko, N. M. Nurullina, M. N. Denisova, Kh. E. Kharlampidi, O. V. Stoyanov Polymer Science Series D, 2023 Abstract Kinetic simulation of cumene oxidation leading to the obtaining of cumene hydroperoxide (the curing initiator for acrylic adhesives) in the presence of a Ca, Sr, Ba chloride complex with dibenzo-18-crown-6 ether as a catalyst is performed. The kinetic model involves a mechanism for the formation of intermediate adducts between reaction mixture components and the catalyst, initiation reactions, the reactions of chain propagation and chain termination, and molecular reactions inherent in cumene oxidation with no catalyst and in the presence of a homogeneous catalyst, as well as specific reactions caused by the chemical features of crown ethers. The model is shown to reflect the experimental time dependences for the cumene hydroperoxide concentration to a complete extent and time dependences for the concentrations of by-products at a qualitative level (the calculated curves reproduce the shapes of the experimental curves). This indicates that, on the whole, the mechanism used for to construct the model is quite correct.
Kinetic Modeling of Synthesis of Cumene Hydroperoxide (a Curing Initiator for Acrylic Glues) in the Presence of Mg, Ca, Sr, or Ba 2-Ethylhexanoate as a Catalyst N. V. Ulitin, N. A. Novikov, K. A. Tereshchenko, D. A. Shiyan, Ya. L. Lyulinskaya, N. M. Nurullina, M. N. Denisova, O. V. Stoyanov, Kh. E. Kharlampidi Polymer Science Series D, 2023 Abstract A kinetic modeling was carried out for the synthesis of cumene hydroperoxide (an initiator of curing for acrylic adhesives) based on cumene oxidation in the presence of Mg, Ca, Sr, or Ba 2-ethylhexanoate as a catalyst. The kinetic model includes the formation reactions of intermediate components of the reaction mixture–catalyst adducts, the initiation reactions, the propagation and chain termination reactions, and molecular reactions characterizing both noncatalytic and catalytic cumene oxidation, as well as specific reactions caused by the catalytic properties of 2-ethylhexanoates of nontransition metals. The kinetic model reproduces the concentrations of reaction mixture components depending on time within the experimental data error, which confirms the kinetic scheme included in the model.
Catalytic properties of metals of the 2nd and 12th groups in cumene oxidation Nikolai V. Ulitin, Konstantin A. Tereshchenko, Nikolay A. Novikov, Daria A. Shiyan, Yana L. Lyulinskaya, Natalia M. Nurullina, Marina N. Denisova, Viktoriya I. Anisimova, Talat Sh. Nurmurodov, Kharlampii E. Kharlampidi Applied Catalysis A General, 2023
The Effect of Ca, Sr, and Ba Chloride Complexes with Dibenzo-18-Crown-6 Ether as Catalysts on the Process Criteria for the Efficiency of Cumene Oxidation (the First Stage in the Chain of Polymer Composite Production) Nikolai V. Ulitin, Nikolay A. Novikov, Yana L. Lyulinskaya, Daria A. Shiyan, Konstantin A. Tereshchenko, Natalia M. Nurullina, Marina N. Denisova, Yaroslav O. Mezhuev, Kharlampii E. Kharlampidi Journal of Composites Science, 2023 A study was made on the effect of Ca, Sr, and Ba chloride complexes with dibenzo-18-crown-6 ether as catalysts on the process criteria of the efficiency of industrial cumene oxidation using kinetic modeling. It is the first stage in the process chain of polymer composite production. The kinetic scheme of the process is made of classical reactions of the radical chain mechanism (reactions of initiation, chain propagation, and chain termination), molecular reactions, reactions of formation of intermediate adducts “component of the reaction mixture—catalyst” and their decomposition, as well as reactions that take into account the specifics of the catalyst used: (1) formation of planar catalyst complexes with various substances; (2) formation of acetophenone along the catalytic path; (3) hydration of the intermediate adduct “α-methylstyrene—catalyst” to the required alcohol. It is shown that the kinetic model fully reproduces the experimental time dependencies of the cumene hydroperoxide concentration in the cumene oxidation and cumene hydroperoxide decomposition. Using the kinetic model, computational experiments were carried out, as a result of which the following conclusions were made: (1) among the considered catalysts, the complex of Sr chloride with dibenzo-18-crown-6 ether should be recognized as the best, provided that it is used at temperatures of 393–413 K and an initial concentration < 2 mmol/L; (2) to ensure selectivity comparable to the selectivity of a non-catalytic process, it is necessary to conduct the catalytic process at a lowest possible initial concentration of any of the considered catalysts.
