Kinetic heterogeneity of neodymium catalyst systems modified with methylaluminoxane

Manuyko, G. V.; Aminova, G. A.; D’yakonov, G. S.; Ahmetov, I. G.; Bronskaya, V. V.

doi:10.1134/s0040579515030082

Cited by 11 publications

(6 citation statements)

References 1 publication

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“… a method of structural optimization of air supply systems of industrial enterprises based on a rational combination of centralized and local methods of compressed air distribution;  a method of the comparison of various solutions of the structure of air supply systems based on the generalization of data on equipment and materials used to solve the problem of an integrated approach to the reconstruction of air supply systems. In some works, the main directions for reducing the energy consumption of the compressor unit are highlighted [5,6]:…”

Section: Methodsmentioning

confidence: 99%

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Decrease of the cost of drying compressed air by heat recovery at the compressor station

Balzamov,

Bronskaya,

Kharitonova

et al. 2024

E3S Web Conf.

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Compressed air is widely used as an energy carrier. The compressed air production systems are a part of the auxiliary systems of offsite facilities. It is worth noting that the production of com-pressed air is quite an energy-intensive process, so the potential for energy saving is quite large. There is increasing the efficiency of the compressed air production by developing technology solutions for air preparation in this work. The system of air drying by cooling and the source of cold are considered in this paper. The paper presents a comparison of cooling systems from steam compression and absorption refrigerating machines from the point of view of heat exchange, energy consumption for their own needs, providing cold with required parameters. The economic effect of the proposed circuit solution is given.

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Section: Methodsmentioning

confidence: 99%

“…To calculate the change in the cost of 1 GJ of produced cold, the resulting savings in annual operating costs should be divided by the annual cooling capacity of the system in accordance with the expression (5):…”

Section: ��mentioning

confidence: 99%

Decrease of the cost of drying compressed air by heat recovery at the compressor station

Balzamov,

Bronskaya,

Kharitonova

et al. 2024

E3S Web Conf.

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show abstract

“…To identify the temperature dependence of the parameters of the polycentric model of polymerization kinetics, the experimental MWD of PP samples synthesized at temperatures T = 40–90 °C [ 1 ] are presented as the superpositions of the Flory distributions of polymer chains produced on each AC type [ 16 ].…”

Section: Computing the Temperature Dependence Of Kinetic Parameters: ...mentioning

confidence: 99%

“…Figure 1 shows the MWD deconvolutions of the PP samples obtained by polymerization at the temperatures studied (T = 40–90 °C). The mass fractions

and the average calculated molecular weights

of the polymer fractions that had been synthesized on the selected AC types were found by the methods proposed in [ 16 ]. The selected five types of AC are numbered in ascending order,

, of the polymer fractions.…”

Section: Computing the Temperature Dependence Of Kinetic Parameters: ...mentioning

confidence: 99%

Temperature Dependence of the Kinetic Parameters of the Titanium–Magnesium Catalyzed Propylene Polymerization

et al. 2022

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This paper provides a study of the liquid-phase polypropylene polymerization on a heterogeneous titanium–magnesium Ziegler–Natta-type catalyst. A kinetic model was developed that included the activation of potential active centers, chain growth, transferring the chains to hydrogen and monomer, and the deactivation of active centers. The model was created to predict the polymerization rate, polymer yield, and average molecular weights of polymer chains where the polymerization temperature changes from 40 to 90 °C. In developing polycentric kinetic models, there is a difficulty associated with evaluating the kinetic constants of the rates of elementary reactions/stages in polymerization. Each heterogeneous titanium–magnesium catalyst (TMC), including a co-catalyst, as well as an internal and an external electron donor, has its own set of kinetic parameters. Therefore, its kinetic parameters must be defined for each new catalyst. The presented algorithm for identifying the kinetic constants of rates starts with a kinetic model that considers one type of active centers. At the second stage, a deconvolutional analysis is used for the molecular weight distribution (MWD) of the gel permeation chromatography (GPC) data of the polypropylene samples and the most probable distribution of Flory chain lengths is found for each type of active centers. At the third stage, the single-center model is transformed into a polycentric kinetic model. For the catalyst system, five types of active centers were identified, together with a mass fraction and a number-average molecular weight for each active center type of the catalyst, which is consistent with the published results for similar Ti-based Ziegler–Natta catalysts.

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“…Currently, the most common and most effective rubber that gives polystyrene the necessary flexibility and toughness, especially at low temperatures, is polybutadiene that is obtained in the presence of a modified organolithium initiating system. The polymerization mechanism using an organolithium catalytic system modified with polyfunctional sodium and magnesium alcoholates differs from the classical one [1][2][3][4][5][6][7][8]. This is caused by the formation of at least two types of active centres and the exchange reactions occurring between them.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the main characteristics of polymer branching taking into account the exchange of activity between polymerization centres

Bronskaya

Игнашина

Aminova

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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The calculation of the main characteristics of the branching of the polymer is presented in the article using the example of polymerization of butadiene in the presence of an organolithium catalytic system modified with polyfunctional sodium and magnesium alcoholates. The addition of a modifier to the catalytic system leads to the participation in the polymerization of at least two types of active centers, which is the reason for some branching of macromolecules. The complemented mathematical model of the periodic process, taking into account the exchange of activity between the two centers, allows to calculate the main characteristics of branching.

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Kinetic heterogeneity of neodymium catalyst systems modified with methylaluminoxane

Cited by 11 publications

References 1 publication

Decrease of the cost of drying compressed air by heat recovery at the compressor station

Decrease of the cost of drying compressed air by heat recovery at the compressor station

Temperature Dependence of the Kinetic Parameters of the Titanium–Magnesium Catalyzed Propylene Polymerization

Calculation of the main characteristics of polymer branching taking into account the exchange of activity between polymerization centres

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