Temat: decomposition kinetics

Skocz do pozycji: 1.

Tytuł:: Thermal Decomposition Kinetics of Hexanitrohexaazaisowurtzitane/Ammonium Perchlorate
Autorzy:: Zhu, Y.-L.
Wang, K.-K.
Shan, M.-X.
Zheng, X.-D.
Jiao, Q.-J.
Wang, J.-S.
Tematy:: hexanitrohexaazaisowurtzitane
ammonium perchlorate
thermal analysis
thermal decomposition kinetics; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358067.pdf Link otwiera się w nowym oknie
Opis:: The thermal decomposition kinetics of hexanitrohexaazaisowurtzitane/ ammonium perchlorate (HNIW/AP) have been investigated by thermogravimetrydifferential scanning calorimetry-mass spectrometry (TG-DSC-MS) simultaneous analysis. TG showed that there were three weight loss processes for the thermal decomposition of the HNIW/AP mixture. The first was ascribed mainly to the thermal decomposition of HNIW, while the second and third were assigned to that of AP. The presence of AP has little effect on the thermal decomposition process of the HNIW component. The apparent activation energy of the thermal decomposition of the HNIW component, calculated by the Kissinger method, was little changed compared to that of neat HNIW. The addition of HNIW to AP caused the onset and end temperatures of the thermal decomposition to be decreased and the decomposition process to be shortened. The high-temperature and lowtemperature decomposition processes of AP became blurred in the presence of HNIW, and this was supported by the MS results.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effect of Nanomaterials on Thermal Stability of 1,3,6,8-Tetranitro Carbazole
Autorzy:: Pourmortazavi, S. M.
Rahimi-Nasrabadi, M.
Rai, H.
Jabbarzadeh, Y.
Javidan, A.
Tematy:: thermal stability
nanomaterial effect
decomposition kinetics
1,3,6,8-tetranitro carbazole
energetic material; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358744.pdf Link otwiera się w nowym oknie
Opis:: 1,3,6,8-tetranitro carbazole (TNC) as a secondary explosive is used in composite explosive formulations in order to reduce the sensitivity and increase the stability of the explosive composites. In this work, the thermal stabilities of pure TNC and its nanocomposites prepared via three different nanoparticles were studied by thermal analysis, i.e. differential scanning calorimetery (DSC) and thermogravimetry (TG) techniques. Thermal analysis data revealed that the thermal behavior of pure TNC is significantly different from the nanocomposites studied. Pure TNC decomposed completely during a single step in the temperature range 385-425 °C. However, the addition of nanoparticles to the TNC powder leads to higher thermal stability in comparison with the pure TNC. The decomposition kinetics of TNC and its nanocomposites were studied by non-isothermal DSC at several heating rates. Thermokinetic and thermodynamic parameters corresponding to the thermal decomposition of pure TNC and nanocomposites were computed and compared. The results showed that the addition of nanoparticles to the TNC powder has a considerable effect on the thermal stability of the explosive.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Synthesis and Characterization of Metal Derivatives of 1,1,2,2-Tetranitraminoethane (TNAE)
Autorzy:: Zhu, C.
Meng, Z.
Xu, Z.
Liu, W.
Liu, Y.
Shi, X.
Xie, T.
Tematy:: Ionic compound
1,1,2,2-tetranitraminoethane
thermal property
safety performance
thermal decomposition kinetics; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358571.pdf Link otwiera się w nowym oknie
Opis:: The introduction of anions and cations into energetic materials can significantly improve their physicochemical and energetic properties. The K, Zn, Ba, Cu and Pb salts of 1,1,2,2-tetranitraminoethane (TNAE) were synthesized using TNAE as the starting material, and were characterized by IR spectroscopy, NMR spectroscopy and elemental analysis. All of the energetic salts exhibited relatively high thermal stabilities (decomposition temperatures ranging from 195.1 °C to 279.3 °C) and high densities (ranging from 2.1 g·cm–3 to 3.7 g·cm–3). It was demonstrated that the introduction of metal ions conveys better thermal stability than covalent TNAE itself. More importantly, the Zn, Ba and Cu salts exhibited good thermal stability, high density, low sensitivity, and therefore have the potential to be a new class of insensitive, highly energetic explosives for practical applications.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Kinetic investigation of the NO decomposition over $V-O-W/Ti(Sn)O_{2}$ catalyst
Autorzy:: Najbar, Mieczysława
Tomašić, Vesna
Banaś, Joanna
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 5.

Tytuł:: Studies of the Ammonia Decomposition over a Mixture Of α - Fe(N) And γ - Fe4n
Autorzy:: Kiełbasa, K.
Arabczyk, W.
Tematy:: catalytic ammonia decomposition
kinetics
iron catalyst; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/779244.pdf Link otwiera się w nowym oknie
Opis:: An industrial pre-reduced iron catalyst for ammonia synthesis was nitrided in a differential reactor equipped with the systems that made it possible to conduct both the thermogravimetric measurements and hydrogen concentration analyser in the reacting gas mixture. The nitriding process, particularly the catalytic ammonia decomposition reaction, was investigated under an atmosphere of ammonia-hydrogen mixtures, under the atmospheric pressure, at 475oC. The nitriding potentials were changed gradually in the range from 19.10-3 to 73.10-3 Pa-0.5 in the reactor for an intermediate area where two phases exist simultanously: Fe(N) and γ’-Fe4. In the area wherein P > 73.10-3 Pa-0.5, approximately stoichiometric composition of γ’ - Fe4N phase exists and saturating of that phase by nitrogen started. The rate of the catalytic ammonia decomposition was calculated on the basis of grain volume distribution as a function of conversion degree for that catalyst. It was found that over γ’ - Fe4N phase in the stationary states the rate of catalytic ammonia decomposition depends linearly on the logarithm of the nitriding potential. The rate was decreasing along with increase in the nitriding potential. For the intermediate area, the rate of ammonia decomposition is a sum of the rates of reactions which occur on the surfaces of both Fe(N) and γ’ - Fe4N.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Thermal Decomposition and Kinetics Studies of AN, KDN and Their Mixtures with and without Catalysts
Autorzy:: Kumar, P.
Joshi, P. C.
Kumar, R.
Tematy:: green oxidizers
phase stabilization
thermal decomposition
thermo-kinetics
catalysts; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358729.pdf Link otwiera się w nowym oknie
Opis:: Potassium dinitramide (KDN) was incorporated in ammonium nitrate (AN) crystals in AN/KDN ratio of 90/10, 75/25 and 50/50 by a co-crystallization method. These mixtures were subjected to thermal decompositional studies (DSC-TG) using a Simultaneous Thermal Analyzer (STA). The catalysts used for the present studies were: i) cupric(II) oxide (CuO) and, ii) copper-cobalt based metal oxide (Cu-Co*). For all catalytic samples, 2% by weight percent of catalyst was added to the total weight of the samples. Thermal decomposition studies were carried out for all the oxidizer samples prepared. Thermal decompositional studies were carried out at three different heating rates, i.e. 3 K/min, 5 K/min and 10 K/min, and the kinetic parameters were computed using the model free Flynn-Wall-Ozawa equation. It has been observed that 50% KDN addition resulted in complete suppression of endothermicity indicating total supression of the phase changes of AN in this temperature range. Further, it was noticed that CuO acts as a better phase stabilizer for AN as compared to Cu-Co*. However, Cu-Co* considerably increased the net exothermic decompositional heat release (J/g) of AN.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 7.

Tytuł:: Mechanism and Kinetics Studies on Non-Isothermal Decomposition of Ludwigite in Inert Atmosphere
Autorzy:: Fu, X.
Chu, M.
Gao, L.
Liu, Z.
Tematy:: ludwigite
non-isothermal decomposition
kinetics
activation energy
model function; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352128.pdf Link otwiera się w nowym oknie
Opis:: Ludwigite is the main available boron-bearing resource in China. In order to enrich the theory system and optimize its utilization processes, this paper study the mechanism and kinetics on non-isothermal decomposition of ludwigite in inert atmosphere by means of thermal analysis. Results show that, the decomposition of serpentine and szajbelyite is the main cause of mass loss in the process. At the end of decomposition, hortonolite and ludwigite are the two main phases in the sample. The average E value of structural water decomposition is 277.97 kJ/mol based on FWO method (277.17 kJ/mol based on KAS method). The results is proved to be accurate and reliable. The mechanism model function of structural water decomposition is confirmed by Satava method and Popescu method. The form of the most probable model function is G(α) = (1 – α)^–1– 1 (integral form) and f (α) = (1 – α)² (differential form), and its mechanism is chemical reaction. This is verified by the criterion based on activation energy of model-free kinetics analysis.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Investigation of the cook-off processes of HMX-based mixed explosives
Autorzy:: Chen, L.
Ma, X.
Lu, F.
Wu, J.
Tematy:: explosives
chemical kinetics
thermal decomposition
cook-off
numerical simulation; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358000.pdf Link otwiera się w nowym oknie
Opis:: In order to investigate the characteristics of the thermal reaction for two kinds of mixed explosives, PBXC-10 (HMX/TATB/Binder, 38/57/5) and JO-8 (HMX/Binder, 95/5), multi-point measured temperature cook-off tests were carried out at different heating rates. The thermal transfer and finite chemical reactions that include the β→δ transition of HMX, and the endothermic and exothermic cook-off processes were analyzed. A 3D model of the explosive cook-off test was developed to simulate the thermal and chemical behaviour in a thermal ignition. The decomposition mechanisms for HMX and TATB are described by the multistep, chemical kinetic model. The thermal properties, decomposition pathways, and chemical kinetic reaction rate constants for each component are used to develop the reaction courses at various weight percentages. The thermal decomposition reaction of a multi-component, mixed explosive can be predicted as long as the chemical kinetics model of each single-base explosive and binder are known. The phase transition of HMX has an influence on the temperature of the explosive, especially for an explosive with a high HMX content. For mixed explosives containing HMX and TATB, most of the heat release is produced by the decomposition of HMX before ignition, but TATB can delay the ignition time and decrease the reaction violence in the cook-off process.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The kinetics of 1,1-dichloroethene (CCl2=CH2) and trichloroethene (HClC=CCl2) decomposition in dry and humid air under the influence of electron beam
Autorzy:: Nichipor, H.
Dashouk, E.
Yacko, S.
Chmielewski, A.
Zimek, Z.
Sun, Y.
Vitale, S.
Tematy:: 1,1-dichloroethene
trichloroethene
electron beam decomposition
theoretical model
kinetics calculation; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148600.pdf Link otwiera się w nowym oknie
Opis:: New experimental data related to the removal of C2H2Cl2 and C2HCl3 in dry and humid (300 ppm of H2O) air at atmospheric pressure and a temperature of 25°C under the influence of electron beam in the dose range 1 < D < 100 kGy are published. Taking into account these experimental data, theoretical models of the decomposition of both compounds and computer simulations were performed by the present authors to find the kinetics of such processes. The influence of active atoms Cl, O and OH radicals on the VOC degradation process has been established. The theoretical model of C2H2Cl2 degradation under the influence of electron beam in dry and humid air describes the C2H2Cl2 decay and formation of the main products like Cl2, COCl2, CO, CO2, HCl, HCOCl and C2H2Cl2O. The results of calculation of the kinetics of C2H2Cl2 decomposition were compared with data obtained experimentally for the C2H2Cl2 concentration range 321-2213 ppm. It was established that the relation between the rate constants of intermediate product decomposition: C2H2Cl3O Ţ C2H2Cl2O + Cl; (k1) C2H2Cl3O Ţ COCl2 + CH2C2; (k2) should be k1/k2 = 40. The theoretical model of C2HCl3 degradation under the influence of electron beam in dry and humid air describes the C2HCl3 decay and formation of the main products like Cl2, COCl2, CO, CO2, HCl, HCOCl and C2HCl3O. A detailed comparison of experimental and theoretical data for the C2HCl3 concentration 108-3206 ppm shows that the relation between the rate constants of intermediate product decomposition: C2HCl4O Ţ C2HCl3O + Cl; (k3) C2HCl4O Ţ COCl2 + CHCl2; (k4) should be k3/k4 =10. It was also found that O2+ ions have been formed in a gas mixture as a result of charge transfer process from N2+ ions, partly in excited form, which may lead to charge transfer to C2HCl3 and degradation of those particles. According to performed calculation, it can be stated that in humid air (300 ppm of H2O) VOC degradation is occurring mainly due to a chain reaction stimulated by Cl atoms, but also OH radicals are playing an important role. In the described gas mixture, the OH radicals are formed in the following reactions: O2+) + H2O + M Ţ (O2+)H2O + M O2+ (H2O) + H2O Ţ O2 + (H3O+)OH (H3O+)OH + H2O Ţ H3O+ + OH + H2O VOC degradation process under the influence of electron beam is more effective in humid air than in dry air for the same initial VOC concentration level. This conclusion is also supported by experimental data. --------------------------------------------------------------------------------
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Investigations on Chemical, Thermal Decomposition Behavior, Kinetics, Reaction Mechanism and Thermodynamic Properties of Aged TATB
Autorzy:: Singh, A.
Kaur, G.
Sarkar, C.
Mukherjee, N.
Tematy:: 1,3,5-triamino-2,4,6-trinitrobenzene
thermal decomposition
kinetics
thermodynamics; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/357970.pdf Link otwiera się w nowym oknie
Opis:: 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is a kind of insensitive high explosive that can be used as an energetic material in nuclear weapon and space applications. In this work, we have studied the effect of aging on the properties of TATB from a 20 year old lot that had been in direct contact with casing and natural environment conditions. The kinetics was studied using the temperature at the maximum reaction rate (peak) and isoconversional methods from TGA and DTA data obtained at five heating rates under a nitrogen atmosphere. The properties investigated for thermal stability indicate that there is no change in the properties during prolonged exposure in natural environment conditions. The activation energy calculated by the Kissinger method was 179.9 kJ·mol−1 by DTG and the 176.9 kJ·mol−1 by DTA. The experimental results of kinetic analysis obtained by isoconversional methods are in good agreement and very close to each other. In the analysis of reaction mechanisms, the reaction models could be probably best described by a surface contraction mechanism using the Coats-Redfern and Criado methods. The thermodynamic parameters such as Gibbs free energy, enthalpy and entropy of activation were also investigated. The self-accelerating decomposition temperature (TSADT) and critical temperature for thermal explosion (Tb) were also calculated.
Dostawca treści:: Biblioteka Nauki

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