Preparation of Anhydrous Magnesium Chloride from MgCl2·6H2O Ⅱ Thermal Decomposition Mechanism of the Intermediate Product

2005 ◽  
Vol 488-489 ◽  
pp. 61-64 ◽  
Author(s):  
Xing Fu Song ◽  
Jin Wang ◽  
Xiang Tian Wang ◽  
Jian Guo Yu
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Chloride ◽  
Decomposition Process ◽  
Isothermal Kinetics ◽  
Thermal Decomposition Mechanism ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Anhydrous Magnesium Chloride ◽  
Three Stages ◽  
Kinetics Of

Magnesium chloride hex-ammoniate (MgCl2·6NH3) is an intermediate to produce anhydrous magnesium chloride (MgCl2) by method of reaction crystallization. MgCl2·6NH3 is decomposed at 670K to produce anhydrous magnesium chloride. The process of thermal decomposition and its non-isothermal kinetics of MgCl2·6NH3 is studied. Results show that the thermal decomposition process is made up of three stages, the thermal decomposition functions and the thermal decomposition kinetics parameters, such as activation energy (E), pro-exponential factor (A) of MgCl2·6NH3 for each step are obtained by means of the Acher differential, the Coats-Redfern integral and multi-accelerated heating rate method. This study provides a valuable theoretical basis for MgCl2·6NH3 decomposition process on industrialization.

Study on the mechanisms and kinetics of complex's thermal decomposition getting anhydrous magnesium chloride

2008 ◽  
Vol 81 (1) ◽  
pp. 133-135 ◽  
Author(s):  
Yu-Long Wu ◽  
Xiao-Fang Huang ◽  
Ming-De Yang ◽  
Shu-Ping Zou ◽  
Jie Dang ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Chloride ◽  
Anhydrous Magnesium Chloride ◽  
Kinetics Of

scholarly journals Effect of ultrasonic field on isothermal kinetics of fullerene polyhydroxylation

2016 ◽  
Vol 48 (2) ◽  
pp. 259-272 ◽  
Author(s):  
Mihajlo Gigov ◽  
Borivoj Adnadjevic ◽  
Jelena Jovanovic
Keyword(s):  
Activation Energy ◽  
Phase Transfer ◽  
Model Fitting ◽  
Ultrasonic Field ◽  
Conventional Heating ◽  
Isothermal Kinetics ◽  
Ammonium Bromide ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Kinetics Of

The isothermal kinetics of fullerene polyhydroxylation under ultrasonic field was investigated. The isothermal kinetic curves of fullerene polyhydroxylation at different temperatures ranging from 293 K to 313 K were determined. By application of the isoconversion method it was established that the reaction of fullerene polyhydroxylation with sodium hydroxide and cetyl trimethyl ammonium bromide as phase transfer catalyst was kinetically an elementary reaction. The model-fitting method confirmed that the kinetics model of first-order chemical reaction best described the kinetics of fullerene polyhydroxylation under ultrasonic field and the kinetics parameters of fullerene polyhydroxylation were determined (Ea,= 29 kJ/mol and lnA=9.4 min-1). It was established that the reaction rate of fullerene polyhydroxylation under ultrasonic field is higher from 1.5 times to 2.2 times than the rate of comparative reaction under the conventional heating. The activation energy is 28% lower than the value of activation energy determined under the conventional heating, whereas the value of pre-exponential factor is 40 times higher. The decreased value of activation energy (Ea,) and pre-exponential factor (lnA) in the ultrasonic field is explained with the increase in the value of ground energy level of the resonant vibration mode (? = 500 cm-1) of C60 molecule (Ag(1) vibrational mode) and toluene molecule (out-of plane bending C-C-C vibration) and with the decreased value of anharmonicity factor.

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Mechanisms and kinetics of initial pyrolysis and combustion reactions of 1,1-diamino-2,2-dinitroethylene from density functional tight-binding molecular dynamics simulations

2019 ◽  
Vol 97 (11) ◽  
pp. 795-804 ◽  
Author(s):  
Dong Xiang ◽  
Weihua Zhu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Density Functional ◽  
Tight Binding ◽  
Combustion Process ◽  
Exponential Factor ◽  
Three Stages ◽  
Dynamics Simulations ◽  
Combustion Processes ◽  
Kinetics Of

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.

Thermal Analysis Kinetics of Pd-Doped SiO2 Organic-Inorganic Hybrid Material

2017 ◽  
Vol 727 ◽  
pp. 272-279 ◽  
Author(s):  
Jing Yang ◽  
Hong Jun Li ◽  
Rui Hua Mu ◽  
Ya Mei Zhao ◽  
Zhi Tong
Keyword(s):  
Thermal Decomposition ◽  
Hybrid Material ◽  
Sol Gel ◽  
Kinetic Mechanism ◽  
Exponential Factor ◽  
Inorganic Hybrid ◽  
Inorganic Hybrid Material ◽  
Exponential Factors ◽  
Thermal Analysis Kinetics ◽  
Kinetics Of

Pd-doped SiO2 organic-inorganic hybrid material (Pd/M-SiO2) was prepared by sol-gel method and characterized by XRD, FTIR spectra and TG/DTG analysis. The most probable kinetic mechanism function, apparent activation energy and pre-exponential factor of the thermal decomposition for Pd/M-SiO2 material were calculated using the combined Coast-Redfern intergral and Αchar differential methods. Pd element in noncalcined Pd/M-SiO2 materials exists in PdCl2 form. FTIR spectroscopy confirmed the existence of hydrophobic Si−CH3 groups. The thermal decomposition process of Pd/M-SiO2 materials can be divided into four stages, with different mechanism functions. The activation energies are 76.37, 146.85, 208.90 and 413.89 kJ·mol−1 for the four stages, respectively, and the pre-exponential factors are 5.04×1012, 7.14×1013, 2.93×1012 and 6.56×1019 s−1, respectively. There is no obvious influence of the existence of metallic Pd0 on the thermal decomposition of methyl.

Studies on the Thermal Decomposition Kinetic of an Nitrate Ester

2012 ◽  
Vol 182-183 ◽  
pp. 1575-1580 ◽  
Author(s):  
Juan Wang ◽  
Da Bin Liu ◽  
Xin Li Zhou
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Decomposition Mechanism ◽  
Thermal Decomposition Mechanism ◽  
Decomposition Kinetic ◽  
Heating Rates ◽  
Exponential Factor ◽  
Nitrate Ester ◽  
Dynamic Function ◽  
Thermal Decomposition Kinetic

The certain nitrate ester explosive has been tested by TG at the heating rates of 10, 15, 20, 25K•min-1. Basing on the TG experiment results the thermal decomposition activation energy has been calculated by the methods of Ozawa, KAS and iteration. And the thermal decomposition mechanism function of the explosive with 38 kinds of dynamic function was deduced by the method of integration. The results show that the thermal decomposition mechanism of the nitrate ester is chemical reaction mechanism. The thermal decomposition kinetic parameters such as average activation energy Ea and pre-exponential factor A are 133.23×103 J•mol-1 and 3.191×107 s-1 respectively.

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