scholarly journals Anionic Polymerization of ε-Caprolactam under the Influence of Water: 2. Kinetic Model

2020 ◽  
Vol 4 (1) ◽  
pp. 8 ◽  
Author(s):  
Rainer Wendel ◽  
Philipp Rosenberg ◽  
Michael Wilhelm ◽  
Frank Henning
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Reaction Kinetics ◽  
Water Content ◽  
Anionic Polymerization ◽  
Polyamide 6 ◽  
External Influences ◽  
Influence Of Water ◽  
Kinetics Of

The reaction kinetics of anionic polymerization for the production of anionic polyamide 6 (aPA6) are widely understood. It is also known that this reaction is very sensitive to external influences such as water. This paper analyzes and quantifies the influence of water on the reaction of ε-caprolactam to anionic polyamide 6. A kinetic model is developed in which the reactive molecules of the activator and catalyst are defined as variables and the concentrations of activator and catalyst as well as water content are considered. A model for the calculation of the reaction kinetics is established and validated with experimental data. The developed model can be used to predict the influence and compensation of water by addition of surplus activator and catalyst during the polymerization of ε-caprolactam.

Kinetic Model with Effect of Water Content for Enzyme-Catalyzed Citronellyl Laurate Esterification Process

2013 ◽  
Vol 284-287 ◽  
pp. 423-428 ◽  
Author(s):  
Siti Asyura Zulkeflee ◽  
Suhairi Abd Sata ◽  
Norashid Aziz
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Water Content ◽  
Model Development ◽  
Initial Water Content ◽  
Initial Water ◽  
Effect Of Water ◽  
Proposed Model ◽  
Optimal Value ◽  
Influence Of Water

A kinetic model with effect of water content for enzyme-catalyzed citronellyl laurate was developed. These models incorporate the combined influences of established kinetics model with the function model on the effect of initial water content with kinetic parameters. The model development was carried out by performing a linear and nonlinear regression based on the behavior of the kinetic parameter profiles and validated with experimental data. Using the developed models, the influence of water content towards the enzyme-catalyzed initial rate of reaction was theoretically explained. It has been shown that the proposed model have good agreement between experimental data and intends to capture the effect of water content towards the conversion of ester. With this model, the optimal value of initial water content for this process could be estimated.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals Mechanism of reaction of silica and carbon for producing silicon carbide

2019 ◽  
Vol 45 ◽  
pp. 146867831989141
Author(s):  
Bahador Abolpour ◽  
Rahim Shamsoddini
Keyword(s):  
Experimental Data ◽  
Silicon Carbide ◽  
Reaction Kinetics ◽  
Direct Effect ◽  
Solid Reaction ◽  
Carbon Reduction ◽  
Temperature Range ◽  
Carbon Particles ◽  
Mechanism Of Reaction ◽  
Kinetics Of

The reaction kinetics of carbon reduction of silica were investigated using thermodynamic concepts and by fitting to relevant models the experimental data obtained for this reduction using a thermogravimetric unit in the temperature range of 1566 to 1933 K. The results show that the only way to produce SiC in this reduction is the reaction of Si, SiO, or SiO2 at the surface or by diffusion of SiO inside the carbon particles while CO and CO2 have no direct effect on the process. The controlling step of this reduction at temperatures lower than 1750 K is the chemical gas–solid or solid–solid reaction at the surface of the carbon particles, while at higher temperatures, the rate of SiO diffusing inside the carbon particles controls the rate of this reduction.

scholarly journals Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 516 ◽  
Author(s):  
Michela Lucian ◽  
Maurizio Volpe ◽  
Luca Fiori
Keyword(s):  
Experimental Data ◽  
Reaction Kinetics ◽  
Reaction Pathway ◽  
Hydrothermal Carbonization ◽  
Kinetics Model ◽  
Transient Phase ◽  
Lumped Model ◽  
Gaseous Products ◽  
Best Fitting ◽  
Kinetics Of

Olive trimmings (OT) were used as feedstock for an in-depth experimental study on the reaction kinetics controlling hydrothermal carbonization (HTC). OT were hydrothermally carbonized for a residence time τ of up to 8 h at temperatures between 180 and 250 °C to systematically investigate the chemical and energy properties changes of hydrochars during HTC. Additional experiments at 120 and 150 °C at τ = 0 h were carried out to analyze the heat-up transient phase required to reach the HTC set-point temperature. Furthermore, an original HTC reaction kinetics model was developed. The HTC reaction pathway was described through a lumped model, in which biomass is converted into solid (distinguished between primary and secondary char), liquid, and gaseous products. The kinetics model, written in MATLABTM, was used in best fitting routines with HTC experimental data obtained using OT and two other agro-wastes previously tested: grape marc and Opuntia Ficus Indica. The HTC kinetics model effectively predicts carbon distribution among HTC products versus time with the thermal transient phase included; it represents an effective tool for R&D in the HTC field. Importantly, both modeling and experimental data suggest that already during the heat-up phase, biomass greatly carbonizes, in particular at the highest temperature tested of 250 °C.

scholarly journals Kinetics of Transesterification of Safflower Oil to Obtain Biodiesel Using Heterogeneous Catalysis

2016 ◽  
Vol 14 (4) ◽  
pp. 929-938 ◽  
Author(s):  
Gabriel E. Galván Muciño ◽  
Rubi Romero ◽  
Armando Ramírez ◽  
María Jesús Ramos ◽  
Ramiro Baeza-Jiménez ◽  
...  
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Heterogeneous Catalysis ◽  
Kinetic Model ◽  
Methyl Esters ◽  
Molar Ratio ◽  
Safflower Oil ◽  
Estimated Parameters ◽  
Kinetics Of ◽  
Best Fit

Abstract The kinetics of the transesterification of safflower oil and methanol catalyzed by K2O/NaX was studied and modeled. The influence of the oil-methanol initial molar ratio and amount of catalyst were investigated to achieve a maximum triglycerides conversion (99 %) and a final methyl esters content of 94 % ±1. A kinetic model based on an Eley–Rideal mechanism was found to best fit the experimental data when assuming methanol adsorption as determining step. Other models derived from Langmuir – Hinshelwood – Hougen –Watson (LHHW) mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the estimated parameters.

General equations for the reaction kinetics of solids

1976 ◽  
Vol 29 (1) ◽  
pp. 27
Author(s):  
JH Taplin
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Reaction Kinetics ◽  
Theoretical Basis ◽  
Reaction Equation ◽  
Kinetics Of

The index-of-reaction equation (i.r.e.): dF/dtZ = kZ(l - βF)m is compared with a generalized Prout-Tompkins equation (g.P.T.e.): dF/dt = kn(l - βF)y With the boundary condition F = 0, t = 0 the equations are equivalent for z = 2 or m = 0 or β ≤ 1 and the i.r.e, is closely approximated by the g.P.T.e. for other values of the parameters by use of the following approximation ∫(1- F)-m dF ≈ AF(1-BF)5 The parameter s is a function of m. Both A and B are close to unity for 1/3 < m < 3. The i.r.e. is recommended as being more useful than the g.P.T.e. because the i.r.e. has a better theoretical basis and because it is more readily integrated and fitted to experimental data.

scholarly journals Kinetics of chemical processes in the human brain. Modeling of the BOLD-signal at f-MRT research

2019 ◽  
Vol 488 (2) ◽  
pp. 157-161
Author(s):  
S. D. Varfolomeev ◽  
N. A. Semenova ◽  
V. I. Bykov ◽  
S. B. Tsybenova
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Human Brain ◽  
Dynamic Behavior ◽  
Nervous Tissue ◽  
Chemical Processes ◽  
External Signal ◽  
Bold Signal ◽  
Brain Modeling ◽  
Kinetics Of

A kinetic model describing the impulse of increasing oxygen in the excited nervous tissue of the human brain in response to an external signal is presented. The model is based on biochemical data and describes experimental data on an impulsed hemodynamic response. The model predicts the dynamic behavior of the process participants, which preceding the oxygen impulse and determining the level of the BOLD-signal.

scholarly journals Kinetics of barite reduction from refractory barite-sulphide ore

10.30544/237 ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 261-268 ◽  
Author(s):  
Miroslav D Sokić ◽  
Vladislav Matković ◽  
Jovica Stojanović ◽  
Branislav Marković ◽  
Vaso Manojlović
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Kinetic Model ◽  
Copper Sulphide ◽  
Influence Of Temperature ◽  
Sulphide Ore ◽  
Lead Zinc ◽  
Complex Structural ◽  
Kinetics Of ◽  
Maximum Removal

Refractory sulphide–barite ore was reduced with carbon in order to release lead, zinc, and copper sulphide from barite-pyrite base. Mineralogical investigations showed that due to the complex structural-textural relationships of lead, copper and zinc minerals with gangue minerals, it is not possible to enrich the ore using the conventional methods of mineral processing. The influence of temperature and time was studied to optimize the conditions, and to determine the kinetics of the barite reduction. The maximum removal of barite from ore was 96.7% at 900oC after 180 min. Chemically controlled kinetic model showed the best compliance with the experimental data. An activation energy of 142 kJ/mol was found.

Kinetic Aspects of the Crystallization of SAPO-5 Molecular Sieves

1992 ◽  
Vol 57 (4) ◽  
pp. 756-766 ◽  
Author(s):  
Jan Kornatowski ◽  
Beate Kanz-Reuschel ◽  
Gerd Finger ◽  
Werner H. Baur ◽  
Martin Bülow ◽  
...  
Keyword(s):  
Experimental Data ◽  
Water Content ◽  
Single Crystals ◽  
Size Distribution ◽  
Kinetic Models ◽  
Molecular Sieves ◽  
Hydrothermal Crystallization ◽  
Nucleation Stage ◽  
Kinetics Of

The kinetics of hydrothermal crystallization of microporous silicoaluminophosphate SAPO-5 have been studied as a function of water content using the templates tripropylamine (TPA) and triethylamine (TEA). The investigation included the formation of the SAPO-5 phase, its growth in large single crystals, and the size distribution of the crystals. An attempt to fit the experimental data to kinetic models of crystallization is presented. The systems studied have been found to be very similar except for the nucleation stage which is mainly responsible for both the dimensions of the resulting crystals and for the purity of the SAPO-5 phase.

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