Chemistry, Organic Chemistry, Chemical Engineering, Catalysis
10
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.
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 Metals of the 2nd and 12th Groups on the Productivity and Selectivity of Cumene Oxidation—The First Stage of the Technological Chain for the Production of Polymer Composites Nikolai V. Ulitin, Daria A. Shiyan, Yana L. Lyulinskaya, Nikolay A. Novikov, Konstantin A. Tereshchenko, Natalia M. Nurullina, Marina N. Denisova, Kharlampii E. Kharlampidi, Yaroslav O. Mezhuev Journal of Composites Science, 2023 The effect of the process temperature and the initial concentration of Mg, Ca, Sr, Ba, Zn, Cd, and Hg 2-ethylhexanoates as catalysts on the productivity and selectivity of the oxidation stage of cumene is studied in the technological chain for the production of polymer composites from cumene; “production of phenol by cumene method (stage 1 is cumene oxidation to cumene hydroperoxide, stage 2 is decomposition of cumene hydroperoxide into phenol and acetone) → production of precursors from phenol → production of polymers from precursors → production of composites from polymers”. A criterion has been introduced that reflects the productivity of cumene oxidation at the moment of reaching the maximum concentration of cumene hydroperoxide, which takes into account the cumene conversion and selectivity achieved in this case in the shortest possible time using the selectivity comparable with the selectivity of a non-catalytic process. It has been shown that the achievement of the maximum value of this criterion, among all the considered catalysts, is ensured by Mg 2-ethylhexanoate at its relatively low initial concentration (1 mmol/L) under conditions of moderately-high process temperatures (393–413 K).
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.
