Thermal Decomposition Mechanism and Non Isothermal Kinetics of Complex of [La_2(P-MBA)_6(PHEN)_2]2H_2O

The complex of [La 2(P MBA) 6(PHEN) 2]2H 2O (P MBA: p methylbenzoate and PHEN: 1,10 phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The thermal behavior of [La 2(P MBA) 6(PHEN) 2]2H 2O in dynamic nitrogen atmosphere was investigated by TG DTG techniques. The results show that the thermal decomposition process of the [La 2(P MBA) 6(PHEN) 2]2H 2O occurs in five steps. The empirical kinetic model for the first step thermal decomposition obtained by Malek method is SB(m,n). The activation energy E and the pre exponential factor lnA for this step reaction are 76.4 kJ·mol -1 and 24.92, respectively.

Study on Non-Isothermal Decomposition Kinetics of Ephedrini Hydrochloridum

The thermal decomposition processes of ephedrini hydrochloridum and its kinetics are studied by TG-DTG techniques. A combined method, which includes Achar method, Coats-Redfera method, and Ozawa method, is put forward for determining kinetic model under non-isothermal conditions. By applying the combined method, it is determined that the thermal decomposition of ephedrini hydrochloridum is subjected to cylindrical symmetric diffusion. And the reaction function isƒ(α)=2(1-α)?, apparent activation energy (115.26±3.55) kJ·mol−1, pre-exponential factor 4.62×108 s−1. Results show that the combined method is feasible and simple.

Studies on Non-isothermal Kinetics of Thermal Decomposition of Strontium Chloride Hexahydrate

The thermal decomposition of the strontium chloride hexahydrate and its kinetics were studied under non isothermal condition in nitrogen by thermogravimetric and derivative thermogravimetric techniques. The intermediate and residue for each decomposition were identified from TG curve. The non isothermal kinetic data were analyzed by the Achar method and the Coats Redfern method. The possible reaction mechanisms were suggested by comparing the kinetic parameters. The kinetic equation for the first stage can be expressed as d α /d t = A exp(- E/RT)(1-α ), the second stage, d α /d t = A exp(- E/RT)3(1-α ) 2/3 , and the third stage, d α /d t = A exp(- E/RT)3/2(1-α ) 2/3 [1-(1- α ) 1/3 ] -1 . Mathematic expressions of the kinetic compensation effects of each stage of the thermal decomposition reaction were also obtained.

Non-isothermal Decomposition Mechanism and Kinetics of LiClO_4 in Nitrogen

The non-isothermal decomposition kinetics of LiClO4 in flow N2 atmosphere was studied. TG-DTA curves show that the decomposition proceeded through two well-defined steps below 900℃, and the mass loss was in agreement with the theoretical value. XRD profile demonstrates that the product of the thermal decomposition at 500℃ is LiCI. For the decomposition kinetics study, the activation energies calculated with the Friedman method were considered as the initial values for non-linear regression and were used for verifying the correctness of the fired models. The decomposition process was fitted by a two-step consecutive reaction： extended Prout-Tompkins equation[Bna, f（α） is （1-α）^nα^α] followed by a lth order reaction（F1）. The activation energies were （215.6±0.2） and （251.6±3.6） kJ/mol, respectively. The exponentials n and a for Bna reaction were （0.25±0.05） and （0.795±0.005）, respectively. The reaction types and activation energies were in agreement with those obtained from the isothermal method, but the exponentials were optimized for better firing and prediction.

Kinetics Study on the Thermal Decomposition of Europium p-methyl-benzoate Complex with 1,10-penanthroline under Non-isothermal Con-ditions

The thermal decomposition reaction of Eu-2(p-MBA)(6)(PHEN)(2) (p-MBA=CH3C6H4COO, methylbenzoate; PHEN=C12H8N2, 1,10-phenanthroline) was studied in a static atmosphere using TG-DTG method. The thermal decomposition process of the complex was determined and its kinetics was investigated. Kinetic parameters were obtained from the analysis of TG-DTG curves by means of the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The most probable mechanism functions of the thermal decomposition reaction for the first stage are: f(alpha) =(1-alpha)(2), g(alpha) = (1-alpha)(-1)-1. The activation energy for the first stage is 255.18 kJ/mol, the entropy of activation DeltaS is 227.32 J/mol and the Gibbs free energy of activation DeltaG is 128.04 W/mol.

Non-isothermal decomposition kinetics and lifetime of Tb2(0-MBA)6(PHEN)2

The thermal decomposition of Tb_2(O-MBA)_6(PHEN)_2 (O-MBA: o-methylbenzoate;PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition bythermogravimetry-derivative thermogravimetry (TG-DTG) techniques. Kinetic parameters were obtainedfrom analysis of TG-DTG curves by the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method.The most probable mechanism function was suggested by comparing the kinetic parameters. The kineticequation for the first stage can be expressed as dα/dt = Aexp(-E/RT)·3(1 - α)^(2/3). Thelifetime equation at mass loss of 10% was deduced as lnτ= -28.7429 + 19797.795/T by isothermalthermogravimetric analysis.

Thermal decomposition mechanism and non-isothermal kinetics of the polyoxometalate of ciprofloxacin with 12-tungstoboric acid

The polyoxometalate complex (CPFX-HCl)(4)H5BW12O40-12H(2)O was prepared in aqueous solution for the first time, and characterized by elemental analysis, IR spectrum, and TG-DTG. The TG-DTG curves showed that its thermal decomposition was a four-step process consisting of the simultaneous collapse of Keggin anion. The intermediate and residue of the decomposition were identified by mean of TG-DTG, IR, and XRD technique. The non-isothermal kinetic data were analyzed by the Achar method and Coats-Redfern method. The apparent activation energy (E) and the pre-exponential factor (In A) of each decomposition were obtained. The most probable thermal decomposition reaction mechanisms were proposed by comparison of the kinetic parameters. The kinetic equation for both the second stage and the third stage can be expressed as d alpha/dt = Ae(-E/RT) -(1 - alpha)(2), and the fourth stage d alpha/dt = Ae(-E/RT) -(1 - alpha). And their mathematic expressions of the kinetic compensation effects of thermal decomposition reaction were also determined.

Non-isothermal kinetics of the first-stage decomposition reaction of the complex of samarium p-methoxybenzoate with 1,10-phenanthroline

The complex of [Sm（p-MOBA）3phen]2 （p-MOBA, p-methoxybenzoate; phen,1 10-phenanthroline） was prepared and characterized by elemental analysis, IR, and UV spectroscopy. The thermal decomposition of the [Sm（p-MOBA）sphen]2 complex and its kinetics were studied under a static air atmosphere by TG-DTG methods. The intermediate and residue for each decomposition stage were identified from the TG curve. The kinetic parameters and mecha- nisms of the first decomposition stage were obtained from the analysis of the TG-DTG curves by a new method of processing the data of thermal analysis kinetics. The lifetime equation at a mass loss of 10% was deduced as lnr= - 30.6795 ＋ 21034.56/Tby isothermal thermogravimelric analysis.

Kinetics of Thermal Decomposition of Nd[(C_5H_ (10)NS_2)_3(C_ (12)H_8N_2)] in Non-Isothermal Conditions

The non-isothermal decomposition reaction of Nd[(C_5H_ 10NS_2)_3(C_ 12H_8N_2)] were carried out by means of TG-DTG and the thermal decomposition mechanism, and the associated kinetics was investigated. The kinetic parameters are obtained from an analysis of the TG-DTG curves at different heating rate by integral and differential methods. The most probable kinetic model function of the decomposition reaction is Maple Power of n=3/2, f(α)=2/3α -1/2 and the apparent activation energy E is 116.67 kJ·mol -1 and the pre-exponential factor lg[A/s -1] is 7.6891.

Decomposition mechanisms and non-isothermal kinetics of LiHC_2O_4·H_2O

The thermal decomposition process of LiHC2O4·H2O from 30 to 600 ℃ was investigated by the thermogravimetric and differential scanning calorimetry (TG-DSC). The phases decomposited at different temperature were characterized by X-ray diffraction (XRD), which indicated the decompositions at 150, 170, and 420℃, relating to LiHC2O4, Li2C2O4, Li2C2O4, and Li2CO3, respectively. Reaction mechanisms in the whole sintering process were determined, and the model fitting kinetic approaches were applied to data for non-isothermal thermal decomposition of LiHC2O4?H2O; finally, the kinetic parameters of each reaction were also calculated herein.

Non-isothermal Decomposition Kinetics of Complexes [Sm(m-MBA)_3phen]_2 and [Sm(o-MOBA)_3phen]_2·2H_2O

In recent years, there has been considerable inte- rest in complexes formed by lanthanide cations and va-rious benzoate derivatives^[1-4], due to their potential application in areas, such as extraction, separation, germicide preparation, catalysis, luminescence, and functional material preparation^[5]. As a continuation of the study on lanthanide carboxylate^[6-13], samarium complexes with m-methylbenzoic acid or o-methoxy- benzoic acid and 1,10-phenanthroline were synthesized and characterized by elemental analysis and IR spec- trometry. The thermal decomposition mechanisms of the two complexes were derived and the corresponding non- isothermal kinetics was studied using the Achar diffe- rential method^[14], the MKN integral method^[15], the non-linear isoconversional integral （ NL-INT）, and dif-ferential（NL-DIF） method^[16,17]. The information of the thermodynamic properties of the complex is impor- tant to characterize and understand the properties of the coordination compound, which could eventually be use-ful in determining their potential application.

Non-isothermal Decomposition Kinetics of K(AHDNE)

The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter（DSC） method. The thermal behavior of K（AHDNE） presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=（1019.63/β）3（1-α）[-ln（1-α）]2/3exp（-1.862× 105/RT）. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） of K（AHDNE） are 162.5 and 171.4 °C, respectively. K（AHDNE） has higher thermal stability than AHDNE.

Synthesis, Characterization, Thermal Decomposition Mechanism and Non-Isothermal Kinetics of Salicylaldehyde Salicylhydrazone and Its Complex of Erbium(Ⅲ)

The salicylaldehyde salicylhydrazone and its complex of Er(Ⅲ) were synthesized. The formulae K·4H_2O(HL=[C_(14)H_(10)N_2O_3]^(2-), the bivalent form of the salicylaldehyde salicylhydrazone) were determined by elemental analysis and EDTA volumetric analysis. Molar conductance, IR, UV and X-ray power diffraction were carried out for the characterizations of the complex and the ligand. There are two stable five-numbered and six-numbered circles in the complex. The thermal decompositions of the ligand and the complex with the kinetic study are carried out by non-isothermal thermogravimetry. The stages of the decompositions were identified by TG-DTG curve. The non-isothermal kinetic data were analyzed by means of integral and differential methods. The possible reaction mechanism and the kinetic equation were investigated by the corresponding kinetic parameters.The activation energy value of the main step decomposition are also calculated by Kissinger′s method and Ozawa′s method.

Thermal Decomposition Behavior and Kinetic Study of Jamadoba Coal and Its Density Separated Macerals: A Non-Isothermal Approach

This kinetic study focuses on determining the thermal gravimetric profile of a particular grade of Indian sub-bituminous coal. A thermogravimetric analyzer (TGA-1000) was employed to investigate the thermal behavior and extract the kinetic parameters of Jamadoba coal and its corresponding density separated macerals. The weight loss was measured in air atmosphere. The coal samples used in this study were obtained from Jamadoba mines, Jharkhand. Samples of 35 mg and 200 μm mean size were subjected to synthetic air atmospheres (21% O2). Heating rates of 2, 5 and 7°C/min were applied until the temperature reached 1400°C, which was kept constant until burnout. Low heating rate was preferred so that devolatilization occurs prior to ignition and combustion. Derivative thermogravimetry (DTG) analysis method was applied to measure the weight changes and rates of weight loss used for calculating the kinetic parameters. The activation energy (Ea) and pre-exponential factor were obtained from model-free methods by applying non-isothermal thermogravimetry analysis.

Characterization and Non-isothermal Decomposition Kinetic Analysis of PS/FeNi_3 Nanocomposites

Polystyrene/iron-nickel （PS/FeNi3） nanocomposites were synthesized via an in-situ polymerization route and characterized by XRD,SEM and FTIR. FeNi3 nanoparticles were characterized by TEM and XRD. The pure FeNi3 nanoparticles （100～125 nm） were highly clustered and percolated through the PS matrix. When the content of FeNi3 nanoparticles reached 5 wt%,an interaction between FeNi3 nanoparticles and PS matrix was observed. The thermal decomposition behavior of PS/FeNi3 nanocomposites was investigated by thermal analysis. The activation energies （E） and pre-exponential factors （lnA） were calculated by using Archar method. The results show that the thermal decomposition of pure PS is a one-dimensional diffusion mechanism. A three-dimensional diffusion mechanism appears when FeNi3 nanoparticles incorporate. The E of PS/FeNi3 nanocomposites with different FeNi3 contents is 217.5,225.3,180.6 and 73.0 kJ·mol-1,and the corresponding lnA is 35.6,34.9,27.5 and 10.4 S-1,respectively.

Non-Isothermal Kinetic Analysis of Thermal Decomposition of the Ca-Bentonite from Santai, China

The thermal decompositions of Ca-bentonites (CaB) from Santai ,Shichuan Province, China over the temperature rage of 30-1100℃ were investigated by simultaneous thermal analyzer. Non-isothermal Kinetic analysis were employed to study the thermal decomposition mechanism by using Netzsch Thermokinetics software. The dependence of the activation energy on conversion degree were evaluated by isoconversional methods. The probably mechanism and the corresponding kinetic parameters were determined by multivariate non-linear regression program.

Non-isothermal kinetics of styrene-butadiene-styrene asphalt combustion

The combustion characteristics of styrene-butadiene-styrene （SBS） asphalt are studied by thermogravimetric analysis （TG/DTG） at four different heating rates. According to the saturates/aromatics/resins/asphaltenes （SARA） fractionation method, the combustion process of SBS asphalt can be divided by Gaussian peak fitting into three main stages： oil content release, resin pyrolysis, and asphaltene and char combustion. When the heating rate increases, the mass losses of the oil content and resin pyrolysis increase, and less asphaltenes are formed at a higher temperature. The activation energy values are calculated by the Coats-Redfern method to be in the range 61.6 kJ/mol-142.9 kJ/mol. The Popescu method is used for the kinetic analysis, and the result shows that the three stages of asphalt combustion can be explained by the sphere phase boundary reaction model, the second order chemical reaction model, nucleation, and its subsequent growth model, respectively.

Cure Kinetics of DGEBA with Hyperbranched Poly(3-hydroxyphenyl) Phosphate as Curing Agent Studied by Non-isothermal DSC

The cure kinetics of diglycidyl ether of bisphenol A （DGEBA） with hyperbranched poly （3-hydroxyphenyl） phosphate（HHPP） as the curing agent was investigated by means of non-isothermal differential scanning calorimetry （DSC） at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene（DHB） as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible --P--O-- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Malek. It was found that the two-parameter autocatalytic model（Sestak-Berggren equation） is the most adequate one to describe the cure kinetics of the studied System at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.

Non-isothermal microwave leaching kinetics and absorption characteristics of primary titanium-rich materials

The non-isothermal leaching kinetics of primary titanium-rich material by microwave heating was investigated,and the temperature-pressure curves of leaching system and microwave absorption characteristics of mixture solutions before and after leaching were measured.The research of non-isothermal kinetics was evaluated by the leaching rate of Fe and the total apparent velocity equation of the non-isothermal kinetics of leaching for primary titanium-rich material by microwave heating was obtained.It is shown from the temperature-pressure curves that the high temperature and high pressure of closed leaching system are favorable to the enhancement of the leaching rate of Fe.Microwave absorption characteristics of mixture solutions before and after leaching show that there are abrupt changes of microwave absorption characteristics for 15%HCl solution and the mixture solution after leaching by 20%HCl.