scholarly journals Kinetic model of photoinitiated copolymerization of monofunctional monomers till high conversions

2009 ◽  
Vol 3 (1) ◽  
pp. 1-6
Author(s):  
Yuriy Medvedevskikh ◽  
◽  
Galyna Khovanets’ ◽  
Iryna Yevchuk ◽  
◽  
...  
Keyword(s):  
Kinetic Model ◽  
Uv Irradiation ◽  
Glycidyl Methacrylate ◽  
Laser Interferometry ◽  
Polymerization Process ◽  
Molar Ratio ◽  
Hydroxyethyl Methacrylate ◽  
Wide Range ◽  
Kinetics Of

Regularities of kinetics of photoinitiated copolymerization till high conversions in the systems of monofunctional methacrylate comonomers (hydroxyethyl methacrylate (HEMA), glycidyl methacrylate (GMA)) have been investigated by laser interferometry in a wide range of experimental factors (molar ratio of comonomers, photoinitiator concentration, intensity of UV-irradiation). Kinetic model of photoinitiated copolymerization of methacrylates till high conversions has been proposed on the basis of microheterogeneity conception of the polymerization process.

scholarly journals Solar Light Induced Photocatalysis for Treatment of High COD Pharmaceutical Effluent with Recyclable Ag-Fe Codoped TiO2: Kinetics of COD Removal

2020 ◽  
Vol 15 (1) ◽  
pp. 137-150
Author(s):  
Darshana Tushar Bhatti ◽  
Sachin Prakashbhai Parikh ◽  
◽  
Keyword(s):  
Uv Irradiation ◽  
Sol Gel ◽  
Analytical Techniques ◽  
High Strength ◽  
Molar Ratio ◽  
Doped Tio2 ◽  
Cod Reduction ◽  
Codoped Tio2 ◽  
Wide Range ◽  
Kinetics Of

A wide range of active pharmaceutical ingredients (API) is found in various water streams. These synthetic non-biodegradable organics create trouble in conventional wastewater treatment due to toxicity. There is a strong need to develop substitute technology such as visible light driven photocatalysis with a reusable photocatalyst to completely oxidize these substances into carbon dioxide and water. Sol-gel method was used for synthesis of Fe doped TiO2 and Ag-Fe codoped TiO2 nanoparticles with 0.5 wt% Fe and Ti/Ag molar ratio 30 (Ag-Fe CT 30). The morphology and structure of nanoparticles were studied using various analytical techniques. Ag-Fe CT 30 photocatalyst has exhibited excellent photocatalytic activity compared to commercial TiO2, undoped TiO2 and Fe doped TiO2 nanophotocatalysts under solar and UV irradiation for removal of an antifungal drug intermediate, Difloro triazole acetophenone (DFTA) from water. COD reduction efficiency was highest with Ag-Fe CT 30 under solar and UV irradiation proves the potential of Ag-Fe CT 30 photocatalyst to absorb both UV as well as visible radiations. Ag-Fe CT 30 has shown good stability for 4 runs without much decline in the efficacy. This study provides insights on the solar application of a reusable Ag-Fe CT 30 photocatalyst for the treatment of high strength COD wastewater. Kinetics of COD reduction by photocatalysis has been determined.

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.

scholarly journals Dehydrogenation of Methylcyclohexane: Parametric Sensitivity of the Power Law Kinetics

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad R. Usman ◽  
David L. Cresswell ◽  
Arthur A. Garforth
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Power Law ◽  
Operating Conditions ◽  
Nonlinear Dependence ◽  
Power Law Model ◽  
Parametric Sensitivity ◽  
Heterogeneous Catalytic ◽  
Wide Range ◽  
Kinetics Of

For heterogeneous catalytic reactions, the empirical power law model is a valuable tool that explains variation in the kinetic behavior with changes in operating conditions, and therefore aids in the development of an appropriate and robust kinetic model. In the present work, experiments are performed on 1.0 wt% Pt/Al2O3 catalyst over a wide range of experimental conditions and parametric sensitivity of the power law model to the kinetics of the dehydrogenation of methylcyclohexane is studied. Power law parameters such as order of the reaction, activation energy, and kinetic rate constants are found dependent upon the operating conditions. With H2 in the feed, both apparent order of the reaction and apparent activation energy generally increase with an increase in pressure. The results suggest a kinetic model, which involves nonlinear dependence of rate on the partial pressure of hydrogen and adsorption kinetics of toluene or some intermediate.

scholarly journals Kinetics of the sunflower oil ethanolysis using CaO as catalyst

2016 ◽  
Vol 22 (4) ◽  
pp. 409-418 ◽  
Author(s):  
Ana Velickovic ◽  
Jelena Avramovic ◽  
Olivera Stamenkovic ◽  
Vlada Veljkovic
Keyword(s):  
Kinetic Model ◽  
Sunflower Oil ◽  
Reaction Rate Constant ◽  
Ethyl Esters ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Data Points ◽  
Kinetics Of ◽  
Good Agreement

The ethanolysis of sunflower oil catalyzed by calcium oxide was studied in wider ranges of the reaction conditions: temperature 65-75?C, ethanol-to-oil molar ratio 6:1-18:1 and catalyst loading 10-20% in order to determine the reaction kinetics. The proposed kinetic model of the sunflower oil ethanolysis included the changing and first-order reaction mechanism with respect to triacylglycerols and fatty acid ethyl esters. The kinetic parameters were determined and correlated with the process variables. The Arrhenius equation could be applied to the reaction rate constant with the activation energy of 94.0 kJ/mol. The proposed kinetic model showed a good agreement with the experimental data with the mean relative percentage deviation of ?13% (based on 256 data points).

scholarly journals Kinetic modeling of canola oil transesterification catalyzed by quicklime

2018 ◽  
Vol 16 (6) ◽  
Author(s):  
J.N. Camacho ◽  
G. E. Galván Muciño ◽  
S.L. Martínez Vargas ◽  
C. Pérez Alonso ◽  
R. Natividad
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Canola Oil ◽  
Reaction Rate ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Minor Effect ◽  
Whole Process ◽  
High Effect ◽  
Kinetics Of

This work aimed to study and model the kinetics of transesterification of canola oil with methanol catalyzed by calcined quicklime (CaO + MgO). The influence of three main variables was studied at 328 K: reagents order addition (has a negligible effect on the reaction), methanol-oil molar ratio (has minor effect on reaction rate after 1.5 h of reaction) and catalyst loading (high effect on reaction rate) to achieve at least a triglycerides conversion of 96.5% in concordance with norm EN 14103. A kinetic model based on an Eley-Rideal mechanism was found to well fit (R2 = 0.9886) the experimental data. Thus, it was concluded that for the quicklime catalyzed transesterification of canola oil with methanol to occur, first the methanol must be chemisorbed and the resulting methoxy species react with triglycerides in the interface liquid-solid. The whole process is limited by this step since methanol readily adsorbs onto the catalytic surface.

Morphogenesis of Photo-Polymerized Dimethacrylate Networks, Kinetics of Curing and Viscoelastic Parameters

2016 ◽  
Vol 851 ◽  
pp. 207-214
Author(s):  
Zdeněk Bystřický ◽  
Josef Jancar
Keyword(s):  
Molecular Structure ◽  
Double Bond ◽  
Kinetic Data ◽  
Complex Modulus ◽  
Polymerization Process ◽  
Molar Ratio ◽  
Structure Evolution ◽  
Degradation Kinetic ◽  
Diffusion Controlled ◽  
Kinetics Of

The paper refers to the process of dimethacrylate networks morphogenesis. These stiff and highly cross-linked networks have been extensively used as a polymeric matrix of dental composites for decades. In the study, common co-monomer mixtures used in dental resin formulations were employed. This includes rigid aromatic base monomers, bisphenol A glycerolate dimethacrylate (Bis-GMA) and its ethoxylated alternative (Bis-EMA). Flexible aliphatic monomer, triethylene glycol dimethacrylate (TEGDMA), was used as the viscosity reducer. Kinetics of the polymerization process was studied regarding the structural differences and varying molar ratio of the co-monomers. Kinetic data provided the base for understanding the supra-molecular structure evolution. Consequently, an attempt to quantify the relationship between the resulting network morphology and complex viscoelastic moduli was made. Curing kinetics was studied using differential photo-calorimetry (DPC). Complex modulus was measured using dynamic-mechanical analysis (DMA). Thermal degradation kinetic data (TGA) were used in order to confirm the estimated morphology of cured networks. Reactivity of the monomer is derived from its molecular structure. The potential for non-covalent physical interactions along with monomer backbone rigidity significantly decrease polymerization rate and resulting double bond conversion. The diffusion-controlled kinetics dominates over the chemically controlled kinetics throughout most of the polymerization process. Dilution by the low viscous and flexible monomer shifts the diffusion-controlled kinetics to the later stages of the polymerization. However, the flexibility of the monomer backbone promotes the origination of structural heterogeneities, characterized by micro-gel domains formation. This is associated particularly with the anomalous pendant double bond reactivity and ineffective cross-linking.

Scintigraphic studies in rats. Kinetics of insulin analogues covering wide range of receptor affinities

Diabetes ◽  
1991 ◽  
Vol 40 (5) ◽  
pp. 628-632 ◽  
Author(s):  
I. Jensen ◽  
V. Kruse ◽  
U. D. Larsen
Keyword(s):  
Insulin Analogues ◽  
Wide Range ◽  
Kinetics Of

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 Torrefaction Thermogravimetric Analysis and Kinetics of Sorghum Distilled Residue for Sustainable Fuel Production

2021 ◽  
Vol 13 (8) ◽  
pp. 4246
Author(s):  
Shih-Wei Yen ◽  
Wei-Hsin Chen ◽  
Jo-Shu Chang ◽  
Chun-Fong Eng ◽  
Salman Raza Naqvi ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Pso Algorithm ◽  
Nitrogen Atmosphere ◽  
Computational Method ◽  
Weight Changes ◽  
Design And Optimization ◽  
Thermogravimetric Analyzer ◽  
Model Free ◽  
Different Temperatures ◽  
Kinetics Of

This study investigated the kinetics of isothermal torrefaction of sorghum distilled residue (SDR), the main byproduct of the sorghum liquor-making process. The samples chosen were torrefied isothermally at five different temperatures under a nitrogen atmosphere in a thermogravimetric analyzer. Afterward, two different kinetic methods, the traditional model-free approach, and a two-step parallel reaction (TPR) kinetic model, were used to obtain the torrefaction kinetics of SDR. With the acquired 92–97% fit quality, which is the degree of similarity between calculated and real torrefaction curves, the traditional method approached using the Arrhenius equation showed a poor ability on kinetics prediction, whereas the TPR kinetic model optimized by the particle swarm optimization (PSO) algorithm showed that all the fit qualities are as high as 99%. The results suggest that PSO can simulate the actual torrefaction kinetics more accurately than the traditional kinetics approach. Moreover, the PSO method can be further employed for simulating the weight changes of reaction intermediates throughout the process. This computational method could be used as a powerful tool for industrial design and optimization in the biochar manufacturing process.

Sign in / Sign up

Export Citation Format

Share Document