Comparison of the dehydration kinetics of solid state compounds of 2-methoxybenzylidenepyruvate with some divalent metal ions

Divalent metal complexes of ligand 2-methoxybenzylidenepyruvate with Fe, Co, Ni, Cu and Zn as well as sodium salt were synthesized and investigated in the solid state. TG curves of these compounds were obtained with masses sample of 1 and 5mg under nitrogen atmosphere. Different heating rates were used to characterize and study these compounds from the kinetic point of view. The activation energy and pre-exponential factor were obtained applying the Wall-Flynn-Ozawa method to the TG curves. The obtained data were evaluated and the values of activation energy (Ea / kJ mol-1) was plotted in function of the conversion degree (α). The results show that due to mass sample, different activation energies were obtained. The results are discussed mainly taking into account the linear dependence between the activation energy and the pre exponential factor, where was verified the effect of kinetic compensation (KCE) and possible linear relations between the dehydrations steps of these compounds.

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Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0130 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1357-1359 ◽

Cited By ~ 5

Author(s):

Y. Hongbo ◽

C. Meiling ◽

W. Xu ◽

G. Hong

Keyword(s):

Activation Energy ◽

Thermal Analysis ◽

Layered Double Hydroxides ◽

Heating Rates ◽

Scanning Calorimetry ◽

Exponential Factor ◽

Thermal Kinetic Parameters ◽

Double Hydroxides ◽

Kinetics Of ◽

Dsc Curves

Abstract The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

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Thermal Cure and Ceramization Kinetics of Perhydropolysilazane

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.575-576.81 ◽

2013 ◽

Vol 575-576 ◽

pp. 81-86 ◽

Cited By ~ 1

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.

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Thermal degradation kinetics of oxo-degradable PP/PLA blends

Journal of Polymer Engineering ◽

10.1515/polyeng-2018-0073 ◽

2018 ◽

Vol 39 (1) ◽

pp. 58-67 ◽

Cited By ~ 4

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.

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Pyrolysis Kinetics Equation of Larch Bark

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.772.313 ◽

2013 ◽

Vol 772 ◽

pp. 313-318

Author(s):

Hong Shuang Du ◽

Xiang Yu Li ◽

Xue Yong Ren ◽

Yan Xue Han

Keyword(s):

Mass Loss ◽

Mass Loss Rate ◽

Kinetic Equations ◽

Nitrogen Atmosphere ◽

Pyrolysis Kinetics ◽

Heating Rates ◽

Linear Temperature ◽

Exponential Factor ◽

Kinetics Of ◽

Pyrolysis Kinetic

The larch bark was examined by non-isothermal means to determine the mass loss kinetics of the thermal decomposition with linear temperature programming in nitrogen atmosphere. In this work, mechanism equation of = was used forCoats-Redfern integral methodat the different heating rates. The apparent activation energy, pre-exponential factor and the pyrolysis kinetic equations at the different heating rates were obtained. The pyrolysis temperature area was divided into two separate temperature regions for the pyrolysis kinetic equation and the two components were decomposed respectively at the two separate temperature regions. The global mass loss rate of the bark is considered as controlled respectively by the reactions of the two components respectively during the lower and higher temperature ranges. The kinetics of the two components are found to abide by the mechanism equation of =, which gave the best fits to the experimental data. The obtained kinetic equations of the bark at the different heating rates were additionally validated by the reasonable agreement between the experimental and calculated results.

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An Experimental Study of the Coking Process

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.2001 ◽

2010 ◽

Vol 8 (1) ◽

Author(s):

Somayeh Ebrahimi ◽

Jafarsadegh Moghaddas

Keyword(s):

Activation Energy ◽

Coke Formation ◽

Nitrogen Atmosphere ◽

Fuel Oil ◽

Effective Parameters ◽

Pyrolysis Kinetics ◽

Exponential Factor ◽

First Order ◽

First Order Kinetics ◽

Kinetics Of

The coking process includes two dynamic and isothermal steps. In this process, some factors control the coke formation kinetics. In this research, effects of some important and effective parameters of feed on the quality of petroleum coke were studied. Two hydrocarbon residue feeds; Cracked Fuel Oil (CFO) and Styrene Monomer Tar (SMTAR) were used at 500°C with atmospheric pressure of nitrogen used as an inert gas. Rate of weight loss and gas evolution from these feeds were considered by data of thermal analysis TG (thermogravimetry) and DTG (derivative thermogravimetry). Based on the results, CFO was assigned as the better feed. After selecting better feed, simultaneous thermogravimetry-differential analysis (TG-DTA) was used to study the pyrolysis kinetics of CFO. Samples were heated in a TG-DTA apparatus in nitrogen atmosphere at a temperature range of 37-600°C. The activation energy (Ea) and pre-exponential factor (A) were calculated from the experimental results by using a three stage Arrhenius-type kinetic model and showed that CFO pyrolysis kinetics at temperature ranges 37-285, 320-450 and 467-600°C follows first, second and first order kinetics, respectively. Attentive to temperature increase and reaction progress, activation energy and pre-exponential factor indicated different values at each stage. Also, kinetics of the isothermal step of coke formation was studied during heating of CFO. Samples were reacted in a tube furnace at 450°C and with nitrogen atmosphere. The kinetics of coke formation for petroleum residue was followed by solvent extraction (insolubility in hexane (HI), toluene (TI)) and a development of TI approximate to apparent first order kinetics. The rate constant at this temperature was calculated and it was also observed that the coke formation had been started at a temperature below 450°C.

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Thermogravimetric Kinetics of Selected Energy Crops Pyrolysis

Energies ◽

10.3390/en13153977 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3977

Author(s):

Magdalena Matusiak ◽

Radosław Ślęzak ◽

Stanisław Ledakowicz

Keyword(s):

Activation Energy ◽

Energy Crops ◽

Pyrolysis Kinetics ◽

Heating Rates ◽

Exponential Factor ◽

Miscanthus Giganteus ◽

Temperature Ranges ◽

The Given ◽

Kinetics Of ◽

Derivative Thermogravimetry

The main purpose of this paper was to compare the pyrolysis kinetics of three types of energy crops: Miscanthus giganteus, Sida hermaphrodita, and Sorghum Moench. Studies were conducted in thermobalance. Feedstock samples were heated up from ambient temperature to 600 °C under an inert argon atmosphere. Three heating rates of β = 5, 10, and 20 °C/min were applied. Reactions occurring in the given temperature ranges were grouped together into so-called lumps identified by the deconvolution of derivative thermogravimetry (DTG) curves that corresponded to biomass compositions (hemicellulose, cellulose, and lignin). For the estimation of the activation energy and pre-exponential factor, the Friedman and Ozawa–Flynn–Wall methods were used. The final kinetic parameters were determined by nonlinear regression assuming that thermal decomposition proceeded via three parallel independent reactions of the nth order. The activation energy of hemicellulose, cellulose and lignin was determined to be in the range of 92.9–97.7, 190.1–192.5, and 170–175.2 kJ/mol, respectively. The reaction order was in the range of 3.35–3.99 for hemicellulose, 1.38–1.93 for cellulose, and 3.97–3.99 for lignin. The obtained results allow us to estimate the pyrolytic potential of energy crops selected for this study, and can be used in designing efficient pyrolizers for these materials.

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Kinetic study of wood chips decomposition by TGA

Chemical Papers ◽

10.2478/s11696-009-0109-4 ◽

2010 ◽

Vol 64 (2) ◽

Cited By ~ 87

Author(s):

Lukáš Gašparovič ◽

Zuzana Koreňová ◽

Ľudovít Jelemenský

Keyword(s):

Activation Energy ◽

Kinetic Parameters ◽

Isoconversional Method ◽

Nitrogen Atmosphere ◽

Decomposition Process ◽

Wood Chips ◽

Water Evaporation ◽

Heating Rates ◽

Exponential Factor ◽

Decomposition Processes

AbstractPyrolysis of a wood chips mixture and main wood compounds such as hemicellulose, cellulose and lignin was investigated by thermogravimetry. The investigation was carried out in inert nitrogen atmosphere with temperatures ranging from 20°C to 900°C for four heating rates: 2 K min−1, 5 K min−1, 10 K min−1, and 15 K min−1. Hemicellulose, cellulose, and lignin were used as the main compounds of biomass. TGA and DTG temperature dependencies were evaluated. Decomposition processes proceed in three main stages: water evaporation, and active and passive pyrolysis. The decomposition of hemicellulose and cellulose takes place in the temperature range of 200–380°C and 250–380°C, while lignin decomposition seems to be ranging from 180°C up to 900°C. The isoconversional method was used to determine kinetic parameters such as activation energy and pre-exponential factor mainly in the stage of active pyrolysis and partially in the passive stage. It was found that, at the end of the decomposition process, the value of activation energy decreases. Reaction order does not have a significant influence on the process because of the high value of the pre-exponential factor. Obtained kinetic parameters were used to calculate simulated decompositions at different heating rates. Experimental data compared with the simulation ones were in good accordance at all heating rates. From the pyrolysis of hemicellulose, cellulose, and lignin it is clear that the decomposition process of wood is dependent on the composition and concentration of the main compounds.

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Crystallization kinetics of glassy Se90In10-xAgx alloys: Observation of Mayer-Neldel rule

Processing and Application of Ceramics ◽

10.2298/pac1603137s ◽

2016 ◽

Vol 10 (3) ◽

pp. 137-142

Author(s):

Karishma Singh ◽

Neeraj Mehta ◽

Sudhir Sharma ◽

Ashok Kumar

Keyword(s):

Activation Energy ◽

Differential Scanning Calorimetric ◽

Crystallization Activation Energy ◽

Heating Rates ◽

Melt Quenching ◽

Exponential Factor ◽

Dsc Studies ◽

Glassy Alloys ◽

Kinetics Of ◽

Arrhenius Expression

Glassy alloys of Se90In10-xAgx were prepared using melt quenching technique. Non-isothermal differential scanning calorimetric (DSC) studies were done on Se90In10-xAgx (x = 0, 2, 4, 6, 8 at.%) glassy alloys at four different heating rates (? = 5, 10, 15, 20?C/min). Well defined endothermic and exothermic peaks were obtained at glass transition (Tg) and crystallization temperature (Tc), respectively. Augis and Bennett?s method was used to obtain the composition dependent crystallization activation energy (Ec) and the pre-exponential factor (?0) of the Arrhenius expression. A linear dependence between ln ?0 and Ec was observed showing the existence of compensation effects of the Meyer-Neldel type. These compensation effects confirm the applicability of Meyer-Neldel (MN) rule for the non-isothermal crystallization in the present case.

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Kinetic Study on Pyrolysis of Gentamicin Residue

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.2803 ◽

2014 ◽

Vol 955-959 ◽

pp. 2803-2808

Author(s):

Ren Ping Liu ◽

Rui Yao ◽

Hui Li

Keyword(s):

Activation Energy ◽

High Temperature ◽

Thermochemical Conversion ◽

Pyrolysis Kinetics ◽

Heating Rates ◽

Exponential Factor ◽

Thermogravimetric Analyzer ◽

Basic Work ◽

Mechanism Function ◽

Kinetics Of

Gentamicin bacteria residue contains high organic compound. The technology of thermochemical conversion can effectively solve the problem of bulk gentamicin residue disposal, research on pyrolysis kinetics of the reaction is the basic work for thermochemical conversion . In this paper, Pyrolysis experiments were carried out in a thermogravimetric analyzer under inert conditions and operated at different heating rates (5, 10, 20 K/min).Two different kinetic models, the iso-conversional Ozawa–Flynn–Wall (Ozawa) models and Satava method were applied on TGA data of gentamicin residue to calculate the kinetic parameters including activation energy, pre-exponential factor and Mechanism function. The results showed that: gentamicin bacteria residue lost most weight of it between 100-650 °C , about 74.23% of the whole sample can decompose under high temperature. The pyrolysis function for gentamicin residue should be G(α) =[-ln(1-α)]3.

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