Dual-Cycle Mechanism Based Kinetic Model for DME-to-Olefin Synthesis on HZSM-5-Type Catalysts

A kinetic model for the olefins synthesis from dimethyl ether on zeolite HZSM‑5 based catalysts is developed. The model includes the reaction pathways for the synthesis of olefins from oxygenates in the olefinic and aromatic cycles according to modern concepts of the dual-cycle reaction mechanism. The kinetic parameters were determined for the time-stable hydrothermally treated catalysts of various activities Mg-HZSM-5/Al2O3, HZSM-5/Al2O3, and Zr-HZSM-5/Al2O3. The kinetic parameters determination and the solution of the ordinary differential equations system were carried out in the Python software environment. The preliminary estimation of the kinetic parameters was carried out using the Levenberg-Marquardt algorithm, and the parameters were refined using the genetic algorithm. It is shown that reactions activation energies for different catalysts are close, which indicates that the priority of the reaction paths on the studied catalysts is the same. Thus, the topology of the zeolite plays a leading role in the determination of the synthesis routes, rather than the nature of the modifying metal. The developed model fits the experimental data obtained in an isothermal reactor in the range of temperature 320–360 °C, specified contact time 0.1–3.6 h*gcat/gC with a relative error of less than 15%.

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Combined Kinetic Analysis of Solid-State Reactions: A Powerful Tool for the Simultaneous Determination of Kinetic Parameters and the Kinetic Model without Previous Assumptions on the Reaction Mechanism

The Journal of Physical Chemistry A ◽

10.1021/jp064792g ◽

2006 ◽

Vol 110 (45) ◽

pp. 12456-12462 ◽

Cited By ~ 156

Author(s):

L. A. Pérez-Maqueda ◽

J. M. Criado ◽

P. E. Sánchez-Jiménez

Keyword(s):

Reaction Mechanism ◽

Solid State ◽

Kinetic Model ◽

Kinetic Analysis ◽

Kinetic Parameters ◽

Simultaneous Determination ◽

Solid State Reactions

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DEVELOPING OF MATLAB APPLICATION FOR DETERMINING THE REACTION KINETICS OF RUBBER VULCANIZATION PROCESS

10.46793/iccbi21.101b ◽

2021 ◽

Author(s):

Dario Balaban ◽

◽

Jelena Lubura ◽

Predrag Kojić ◽

Jelena Pavličević ◽

...

Keyword(s):

Kinetic Model ◽

Reaction Kinetics ◽

Kinetic Parameters ◽

Degradation Process ◽

Complex Process ◽

Quality Of Fit ◽

Kinetics Of ◽

Vulcanization Process

Rubber vulcanization is kinetically a complex process, since it consists of two simultaneous reactions: curing and degradation. To determine reaction kinetics, it is necessary to determine a kinetic model which describes the process adequately. Proposed kinetic model has six adjustable parameters. In order to determine kinetic parameters of the proposed kinetic model, commercially available rubber gum was used. Oscillating disc rheometer was used to investigate experimental dependence of torque on time, at six temperatures in the range from 130 to 180 °C, with a step of 10 °C. Matlab application, built via App Designer feature, was developed in order to fit the experimental data to the proposed kinetic model. Developed Matlab application, consisting of two tabs, enables user to upload raw rheometer data, perform manual fitting or automatic fitting (manual or automatic estimation of initial values of adjustable parameters), test the effect of constant values of some kinetic parameters on the overall quality of fit, visualize the dependence of kinetic parameters on temperature and to determine the values of Arrhenius expression for curing and degradation process. Both fitting methods were proven to be efficient; overall determination coefficient and MAPE value for automatic and manual fitting methods were >0.99 and <1%, and >0.999 and <1%, respectively. Arrhenius parameters were also determined with high accuracy (R2>0.98). Developed application enables simple and efficient determination of kinetic parameters by means of different fitting methods, simultaneous fitting of data on all temperatures, and testing the effect of constant kinetic parameters values on fitting results

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Kinetics of anaerobic cometabolism of 2,4-dinitrotoluene with ethanol as the primary substrate

Water Science & Technology ◽

10.2166/wst.1997.0600 ◽

1997 ◽

Vol 36 (6-7) ◽

pp. 271-278 ◽

Cited By ~ 1

Author(s):

Jiayang Cheng ◽

Makram T. Suidan ◽

Albert D. Venosa

Keyword(s):

Kinetic Model ◽

Kinetic Parameters ◽

Competitive Inhibition ◽

Methanogenic Bacteria ◽

Experimental Results ◽

Marquardt Algorithm ◽

Levenberg Marquardt ◽

Kinetics Of ◽

Primary Substrate

A kinetic model that describes the anaerobic cometabolism of 2,4-dinitrtoluene (DNT) with ethanol as the primary substrate has been developed based on experimental results. The kinetic parameters were estimated using the Levenberg-Marquardt algorithm. 2,4-DNT is anaerobically biotransformed to 2,4-diaminotoluene (DAT) via 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) by the bacteria whose growth is supported by utilizing ethanol. 2,4-DNT shows inhibition to its own biotransformation. It also exhibits a very strong competitive inhibition to further biotransformation of 4-A-2-NT and 2-A-4-NT. All the aromatics in the system, 2,4-DNT, 4-A-2-NT, 2-A-4-NT, and 2,4-DAT, inhibit the conversion of ethanol. Hydrogen produced from the acetogenesis of ethanol is utilized for the transformation of the nitroaromatics. The utilization of hydrogen and acetate by methanogenic bacteria is very strongly inhibited by the presence of the nitroaromatics. Acetate exhibits strong competitive inhibition to the biodegradation of propionate.

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MEASUREMENT OF STEROID BINDING PROTEINS

Acta Endocrinologica ◽

10.1530/acta.0.065s104 ◽

1970 ◽

Vol 65 (1_Suppl) ◽

pp. S104-S121 ◽

Cited By ~ 24

Author(s):

E. E. Baulieu ◽

J. P. Raynaud ◽

E. Milgrom

Keyword(s):

Kinetic Parameters ◽

Binding Proteins ◽

Binding Specificity ◽

Binding Parameters ◽

Target Organs ◽

Biological Mixtures ◽

Steroid Binding Proteins ◽

Steroid Binding ◽

Steroid Binding Protein

ABSTRACT A brief review of the characteristics of steroid binding proteins found in the plasma and in some target organs is presented, followed by some general remarks on binding »specificity« and binding parameters. Useful techniques for measuring binding parameters at equilibrium are reported, both those which keep the equilibrium intact and those which implicate its disruption. A concept is developed according to which the determination of a specific steroid binding protein is based on the »differential dissociation« of the several steroid binding complexes present in most biological mixtures. Methods which allow determination of the kinetic parameters of the binding systems are also presented. Various representations of the binding and therefore different modes of graphic representation and calculation are discussed, including the recent »proportion graph« method.

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Regeneration Mechanism Studied by Potential-Time Response to Sinusoidal Current-Time Function

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19971511 ◽

1997 ◽

Vol 62 (10) ◽

pp. 1511-1526

Author(s):

María-Luisa Alcaraz ◽

Ángela Molina

Keyword(s):

Kinetic Parameters ◽

Rate Constant ◽

Theoretical Study ◽

Time Function ◽

Time Response ◽

Current Time ◽

Regeneration Mechanism ◽

Sinusoidal Current ◽

Regeneration Processes

A theoretical study of the potential-time response to sinusoidal current applied to static and dynamic electrodes for regeneration processes is presented. Methods for determination of the regeneration fraction, rate constant of the chemical reaction and heterogeneous kinetic parameters are proposed.

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