scholarly journals Development of a Mathematical Model for Kinetics of Obtaining Isocyanate via a Non-Phosgene Method for Example Benzylisocyanate

2020 ◽  
Vol 8 (4) ◽  
pp. 1491-1497
Keyword(s):  
Activation Energy ◽  
Mathematical Model ◽  
Kinetic Parameters ◽  
Kinetics Of

The paper considers theprocess of developing a mathematicalmodel for kineticsof obtainingisocyanates via a non-phosgene method non-catalytic thermolysis of carbamates. A mathematical model is presented, kinetic parameters such as activation energy and a pre—exponential multiplier are ascertained.

Study on Curing Kinetics of MEP-15/593/660 System

2014 ◽  
Vol 988 ◽  
pp. 31-35
Author(s):  
Jia Le Song ◽  
Chan Chan Li ◽  
Zhi Mi Zhou ◽  
Chao Qiang Ye ◽  
Wei Guang Li
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Kinetic Parameters ◽  
Curing Kinetics ◽  
Conversion Ratio ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Curing Kinetic ◽  
The Relationship ◽  
Kinetics Of

Curing kinetics of MEP-15/593 system and MEP-15/593/660 system is studied by means of differential scanning calorimetry (DSC). Curing kinetic parameters are evaluated and the relationship between diluent 660 and the curing properties is investigated. The results show that the diluent 660 can not only reduce viscosity and activation energy, but also improve the degree of cure and conversion ratio.

Research on Pyrolysis Kinetics of Shenhua Coal and Direct Liquefaction Residue

2012 ◽  
Vol 550-553 ◽  
pp. 2758-2762 ◽  
Author(s):  
Xi Jie Chu ◽  
Yong Gang Wang ◽  
Li Hong Zhao
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Coal Pyrolysis ◽  
Pyrolysis Kinetics ◽  
Differential Heating ◽  
Pyrolysis Behavior ◽  
Direct Liquefaction ◽  
Kinetics Of

The pyrolysis tests of Shenhua coal and Shenhua direct liquefaction residue have been carried out using thermogravimetric at the differential heating rate. The kinetic parameters k and E were calculated using DAEM method. Results show DAME model can describe the pyrolysis behavior of Shenhua coal within the range of 20% to 95%, the activation energy of coal pyrolysis ranges from 53.98 to 279.38 kJ/mol, and DAME model can describe the behavior of Shenhua direct liquefaction residue within the range of 10% to 80%, the activation energy of residue pyrolysis is about 170 kJ/mol. The results of which are basically consistent with the experimental data.

scholarly journals The kinetics of the extraction of caffeine from guarana seed under the action of ultrasonic field with simultaneous cooling

2019 ◽  
Vol 9 (1) ◽  
pp. 26-36 ◽  
Author(s):  
Biljana Koturevic ◽  
Borivoj Adnadjevic ◽  
Jelena Jovanovic
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Reaction System ◽  
Ultrasonic Field ◽  
Conventional Heating ◽  
Isothermal Kinetics ◽  
Correlation Relationship ◽  
Exponential Factor ◽  
Caffeine Extraction ◽  
Kinetics Of

AbstractThe kinetics of isothermal extraction of caffeine from guarana seed under the action of ultrasonic field with simultaneous cooling (UESC) was investigated. The isothermal kinetics curves were measured at temperatures range T = 17-58°C. Using the model-fitting method it was determined that the kinetics of caffeine extraction can be described by a theoretical Jander three-dimensional diffusional model. The values of the rate constant were calculated for different temperatures, as well as the kinetic parameters (activation energy (Ea) and pre-exponential factor (lnA)). Based on the results obtained, it is concluded that the rate constants of caffeine extraction under UESC are about 2 times higher in comparison to the values obtained for the extraction in the conditions of conventional heating (CH). The activation energy of the caffeine extraction under the UESC $\left( E_{\text{a}}\,^{\text{UESC}}=19.4\,\text{kJ}\cdot \text{mo}{{\text{l}}^{-1}} \right)$is lower than the values are for CH $\left( E_{\text{a}}\,^{\text{CH}}=21.8\,\text{kJ}\cdot \text{mo}{{\text{l}}^{-1}} \right).$Energy consumption for UESC is four times lower than for CH conditions. It is shown that there is a linear correlation relationship between kinetic parameters obtained for UESC and CH conditions. The changes in the values of kinetic parameters are explained by the model of selective transfer of energy from the reaction system to the reactant molecules.

Effect of Temperature on the Electrode Kinetics of Totally Irreversible and Quasi-Reversible Polarographic Reductions

1977 ◽  
Vol 32 (4) ◽  
pp. 416-419 ◽  
Author(s):  
Sudhindra Swarup Sharma ◽  
S. K. Jha ◽  
Mukhtar Singh
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Effect Of Temperature ◽  
Electrode Kinetics ◽  
Polarographic Behaviour ◽  
Kinetics Of ◽  
Reversible Reduction

The polarographic behaviour of Ni(II), Co(II), Zn(II) and Mn(II) has been studied in 0.1 M KNO3. The temperature span studied varies from 15 to 55 °C. The reduction of Ni(II) and Co(II) has been found to be totally irreversible and that of Zn(II) and Mn(II) quasi-reversible over the temperature span studied. The kinetic parameters, kf,h0 and ana for the totally irreversible reductions have been calculated by KOUTECKY’S treatment while for quasi-reversible reduction the kinetic parameters (a and ks,h) have been evaluated by GELLINGS’ method. The activation energy of the totally irreversible reductions has also been determined. The effect of temperature has been discussed in terms of the variations in the values of the kinetic parameters.

Thermal Cure and Ceramization Kinetics of Perhydropolysilazane

2013 ◽  
Vol 575-576 ◽  
pp. 81-86 ◽  
Author(s):  
Feng Ling Ma ◽  
Hui Min Qi ◽  
Ya Ping Zhu ◽  
Xiao Wen Ren ◽  
Fan Wang
Keyword(s):  
Activation Energy ◽  
Weight Loss ◽  
Thermogravimetric Analysis ◽  
Kinetic Parameters ◽  
Nitrogen Atmosphere ◽  
Thermal Cure ◽  
Exponential Factor ◽  
Kinetics Of

The kinetics of the thermal cure and ceramization of preceramic prehydropolysilazane (PHPS) was investigated by thermogravimetric analysis (TGA) under nitrogen atmosphere. The results indicated that the gases captured during the thermal cure and ceramization process of PHPS, which had three main weight loss events. The corresponding kinetic parameters including activation energy, pre-exponential factor and empirical order of the thermal cure and ceramization stages were evaluated by using Ozawa and Kissinger metnods, respectively.

Pyrolysis Characteristics and Kinetics of Cassava Residues

2014 ◽  
Vol 953-954 ◽  
pp. 325-329
Author(s):  
Jin Wei Jia ◽  
Di Yang ◽  
He Long Hui ◽  
Xing Min Fu ◽  
Lu Liu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Fixed Bed ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Biomass Feedstock ◽  
Pyrolysis Characteristics ◽  
Three Samples ◽  
Bio Oil ◽  
Kinetics Of

The aims of this work were to investigate the influence of feedstock properties of different part of cassava residues (cassava rhizome (CR), cassava stalk (CS) and cassava leaf (CL)) and operating temperatures on the pyrolysis characteristics and the kinetic parameters. Pyrolysis experiments of three selected biomass feedstock were conducted using a fixed-bed reactor. It was shown that the bio-oil yield of cassava stalk reached the maxima at 600°C, and the char yield reduced with the temperature, whereas the gas yield increased with temperature. The cassava rhizome presented higher thermochemical reactivity than the other samples. The activation energy of cassava stalks was 37.57 kJ / mol and that of cassava rhizome (39.42 kJ / mol) increased slightly. The activation energy of cassava leaf (22.85 kJ / mol) was lowest of the three samples.

Thermal degradation kinetics of oxo-degradable PP/PLA blends

2018 ◽  
Vol 39 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Degradation Kinetics ◽  
Nitrogen Atmosphere ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Kinetics Of

AbstractIn this article, the influence of polylactide and pro-oxidant on the thermal stability, degradation kinetics, and lifetime of polypropylene has been investigated using thermogravimetric analysis under nitrogen atmosphere at four different heating rates (i.e. 5, 10, 15, and 20°C/min). The kinetic parameters of degradation were studied over a temperature range of 30–550°C. The derivative thermogravimetric curves have indicated single stage and two stage degradation processes. The activation energy was evaluated by using the Kissinger, Kim-Park, and Flynn-Wall methods under the nitrogen atmosphere. The activation energy value of polypropylene was much higher than that of polylactide. Addition of polylactide and pro-oxidant in polypropylene decreased the activation energy. The lifetime of polypropylene has also decreased with the addition of polylactide and pro-oxidant.

Kinetics of Carbothermic Reduction of Ilmenite

2016 ◽  
Vol 852 ◽  
pp. 315-322 ◽  
Author(s):  
Min Chen ◽  
Xuan Xiao ◽  
Xue Feng Zhang
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Carbothermic Reduction ◽  
Reduction Process ◽  
Phase Evolution ◽  
Reduction Kinetics ◽  
Isokinetic Relationship ◽  
Exponential Factor ◽  
Morphology Change ◽  
Kinetics Of

The reduction kinetics of ilmenite was investigated. Phase evolution during the reduction process was identified by XRD and morphology change was observed using SEM. Kinetic parameters of the activation energy and pre-exponential factor were determined by Kissinger-Akahira-Sunose (KAS) method and Coast-Redfern method&artificial isokinetic relationship (IKP) respectively. Results showed that when the reaction of titanium suboxides makes a growing contribution, the conversion dependence of activation energy has an ascending trend. When the conversion exceeded 0.7, the reactants almost consumed, and the process was controlled by diffusion.

Kinetics of the Mercury-Photosensitized Decomposition of Propane. Part II. Reactions of the Propyl Radicals

1971 ◽  
Vol 49 (4) ◽  
pp. 549-554 ◽  
Author(s):  
M. M. Papic ◽  
K. J. Laidler
Keyword(s):  
Activation Energy ◽  
High Pressure ◽  
Kinetic Parameters ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Entropy Changes ◽  
A Value ◽  
Yield Information ◽  
Temperature And Pressure ◽  
Kinetics Of

The results of the previous paper are analyzed to yield information about the reactions of the n-propyl and i-propyl radicals. The various combination and disproportionation reactions are considered. The rate of decomposition of the n-propyl radical was determined as a function of temperature and pressure, and limiting high-pressure and low-pressure kinetic parameters were obtained. The high-pressure activation energy is 32.6 kcal mol−1, and this leads to a value of 24.3 kcal mol−1 for the dissociation energy of the C—C bond in the n-propyl radical, to 22.2 kcal mol−1 for its heat of formation, and to 99.1 kcal mol−1 for the primary C—H dissociation energy in propane. Entropy changes are also calculated from the results.For the decomposition of the i-propyl E∞ = 38.7 kcal mol−1, and this leads to 37.7 kcal mol−1 for the C—H bond dissocation energy in this radical and to 19.3 kcal mol−1 for its heat of formation. The secondary C—H dissociation energy in propane is calculated to be 96.2 kcal mol−1. Corresponding entropy changes are calculated.

Kinetics of the thermal inactivation of the Lactococcus lactis bacteriophage P008

2005 ◽  
Vol 72 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Mareile Müller-Merbach ◽  
Horst Neve ◽  
Jörg Hinrichs
Keyword(s):  
Activation Energy ◽  
Thermal Resistance ◽  
Protective Effect ◽  
Regression Model ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Thermal Inactivation ◽  
Inactivation Kinetics ◽  
Kinetics Of ◽  
Phage Inactivation

The thermal resistance of the lactococcal bacteriophage P008 was investigated between 55 and 80 °C. Inactivation kinetics revealed an order of reaction above 1 and could be determined by a non-1st-order regression model. Phage inactivation was influenced by the medium (milk and Ca-M17-broth). Within the investigated temperature range, milk had a protective effect on phage P008. This was reflected in the rate constant and in the activation energy. Thermal phage inactivation studies reported in literature were re-analysed using non-1st-order regression. The obtained kinetic parameters showed that phage P008 belongs to the most heat resistant lactococcal phages investigated so far.

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