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2.
Chengfang Qiao Lei Lü Wenfeng Xu Zhengqiang Xia Chunsheng Zhou Sanping Chen Shengli Gao 《物理化学学报》2020,36(6):1905085-0
Solvent molecules can significantly reduce the heat of detonation and stability of energetic metal-organic framework (EMOF) materials, and the development of solvent-free EMOFs has become an effective strategy to prepare high-energy density materials. In this study, a solvent-free EMOF, [Ag2(DTPZ)]n (1) (N% = 32.58%), was synthesized by reacting a high-energy ligand, 2, 3-di(1H-tetrazol-5-yl)pyrazine (H2DTPZ), with silver ions under hydrothermal conditions, and it was structurally characterized by elemental analysis, infrared spectroscopy, X-ray diffraction, and thermal analysis. In 1, the DTPZ2− ligands that adopted a highly torsional configuration bridged the Ag+ ions in an octadentate coordination mode to form a three-dimensional framework (ρ = 2.812 g∙cm−3). The large steric effect and strong coordination ability of DTPZ2− effectively prevented the solvent molecules from binding with the metal centers or occupying the voids of 1. Moreover, the strong π-π stacking interactions [centroid-centroid distance = 0.34461(1) nm] between the tetrazole rings in different DTPZ2− ligands provided a high thermal stability to the framework (Te = 619.1 K, Tp = 658.7 K). Thermal analysis showed that a one-step rapid weight loss with intense heat release primarily occurred during the decomposition of 1, suggesting potential energetic characteristics. Non-isothermal thermokinetic analyses (based on the Kissinger and Ozawa-Doyle methods) were performed using differential scanning calorimetry to obtain the thermoanalysis kinetic parameters of the thermodecomposition of 1 (Ea = 272.1 kJ·mol−1, Eo = 268.9 kJ·mol−1; lgA =19.67 s−1). The related thermodynamic parameters [enthalpy of activation (ΔH≠ = 266.9 kJ·mol−1), entropy of activation (ΔS≠ = 125.4 J·mol−1·K−1), free energy of activation (ΔG≠ = 188.3 kJ·mol−1)], critical temperature of thermal explosion (Tb = 607.1 K), and self-accelerating decomposition temperature (TSADT = 595.8 K) of the decomposition reaction were also calculated based on the decomposition peak temperature and extrapolated onset temperature when the heating rate approached zero. The results revealed that 1 featured good thermal safety, and its decomposition was a non-spontaneous entropy-driven process. The standard molar enthalpy for the formation of 1 was calculated to be (2165.99 ± 0.81) kJ·mol−1 based on its constant volume combustion energy determined using a precise rotating oxygen bomb calorimeter. Detonation and safety performance tests revealed that 1 was insensitive to impact and friction, and its heat of detonation (10.15 kJ·g−1) was higher than that of common ammonium nitrate explosives, such as octogen (HMX), hexogene (RDX), and 2, 4, 6-trinitrotoluene (TNT), indicating that 1 is a promising high-energy and insensitive material. 相似文献
3.
Thermal decomposition kinetics of ML2 (M = Ni(II) and Co(II); L = 5-(2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione) complexes were investigated by thermogravimetric analysis (TGA). The first decomposition process of the NiL2 and CoL2 complexes occurs in the temperature range of 320–350 °C. Kinetics parameters corresponding to this step, such as activation energy, Eα, and apparent pre-exponential factor, ln Aaap, were calculated from the thermogravimetric data at the heating rates of 5, 10, 15 and 20 K min−1 by differential (Friedman's equation) and integral (Flynn–Wall–Ozawa's equation) methods. The results show that the activation energy evidently depends on the extent of conversion. As far as their activation energy is concerned, NiL2 complex shows a higher thermal stability than the CoL2 complex. 相似文献
4.
Małecka Barbara Drożdż-Cieíla Ewa Olszewski P. K. 《Journal of Thermal Analysis and Calorimetry》2003,74(2):485-490
The kinetics of manganese(II) oxalate thermal decomposition in the helium atmosphere was studied on the basis of isothermal
measurements in the temperature range from 608 to 623 K. Manganese(II) oxide, MnO, was found to be the final product of reaction.
The Avrami-Erofeev kinetic equation was used to describe all the experimental data in the range of decomposition degrees from
0.1 to 0.9. The determined activation energy equals 184.7 kJ mol-1 with standard deviation ±5.2 kJ mol-1. The estimated value of parameter n is 1.9 with standard deviation ±0.01 what suggests that the rate limiting step of MnC2O4 decomposition is the nucleation of new MnO phase and that the rate of nuclei growth is rising during decomposition.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
David Uhrig Ralf Schlegel Roland Weidisch Jimmy MaysAuthor vitae 《European Polymer Journal》2011,(4):560-568
The synthesis of well-defined multigraft copolymers having a polydiene backbone with polystyrene side chains is briefly reviewed, with particular focus on controlling branch point spacing and branch point functionality. Use of living anionic polymerization and chlorosilane linking chemistry has led to the synthesis of series of materials having regularly spaced trifunctional (comb), tetrafunctional (centipede), and hexafunctional (barbwire) branch points. The morphologies of these materials were characterized by transmission electron microscopy and small-angle X-ray scattering, and it was found that the morphologies were controlled by the local architectural asymmetry associated with each branch point. Mechanical properties studies revealed that such multigraft copolymers represent a new class of thermoplastic elastomers (TPEs) with superior elongation at break and low residual strains as compared to conventional TPEs. 相似文献
6.
The main purpose of this work is proposing a new method of using non-isothermal formal kinetics analysis to predict the lifetime of luminescent complex materials. The Eu(III)-phenanthroline complex doped xerogel has been in situ synthesized by a catalyst-free sol-gel method. The photoluminescence spectra and TG curves of the xerogel verify the formation and decomposition of Eu(III)-phenanthroline complex in xerogel. The decomposition of the xerogel formally occurs in three steps. The Friedman and FWO isoconversional methods and multivariate non-linear regression method are used for formal kinetic analysis. The overall decomposition process below 800 °C is fitted by three-step consecutive reaction. The best fitted model for each step is Fn (n order reaction, the corresponding function f(α) is (1 − α)n). Correlation coefficient is 0.99956. The lifetime values of xerogel at different temperatures are predicted based on non-isothermal kinetic models by the 5% decomposition of europium organic complex. 相似文献
7.
The kinetics of the thermal decomposition of bis(2,2-dinitropropyl)-N-fluoroamine are studied in the liquid phase. The reaction is autocatalytic in a melt. In dilute solution, the reaction rate is described by the first-order law. It is tens of times faster in polar sulfolan than in weakly polar dimethyl phthalate. A mechanism of the decomposition involving the formation of a cyclic transition state at the first, limiting stage of the process is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 874–877, May, 1995.This work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-08103). 相似文献
8.
研究了过氧化苯甲酸叔丁酯的热分解动力学及不同包装规格下的自加速分解温度(SADT),利用C600微量热仪测试了过氧化苯甲酸叔丁酯的热分解特征,得到升温速率分别为0.1 K/min、0.2 K/min、0.5 K/min、1 K/min下热流随时间的变化曲线,并使用Friedman等转化率法对所得的实验数据进行分析处理,得到了过氧化苯甲酸叔丁酯的分解反应活化能、指前因子等热动力学参数,推算了不同包装规格的过氧化苯甲酸叔丁酯的SADT。结果表明TBPB分解活化能及指前因子随转化率变化而变化,活化能范围为42-135.5 kJ/mol,指前因子范围为0.25-33.5,在25L聚乙烯桶包装下的SADT为59℃,50L下为52℃,200L下为46℃。 相似文献
9.
Çi?dem Kad? 《European Polymer Journal》2003,39(2):269-273
Several dimeric peroxycarbamates (PCs) have been synthesized by using cycloaliphatic and aromatic diisocyanates with mono- and di-hydroperoxides. The reactions were carried out under suitable conditions either in the presence of T-12 (dibutyltin dilaurate) as catalyst or in the absence of this catalyst. The products were characterized by IR-spectra and molecular weight measurements from isocyanate and peroxygen analyses. Thermal decomposition kinetics of these PCs were studied in THF solution at 80, 90 and 100 °C; the reactions were found to be first-order and decomposition rate constants (kd) were found. Activation energies and frequency factors for the decomposition were calculated. Activation energies were found to be in the range 67-121 kJ mol−1 and frequency factors were of the order of 1011-1015 s−1 depending on the structure of the PC. The results for the PCs agree well with literature values. 相似文献
10.
J. Straszko J. Możejko M. Olszak-Humienik 《Journal of Thermal Analysis and Calorimetry》1995,45(5):1109-1116
The paper describes the kinetics of all the recorded steps of thermal decomposition of nickel sulfate hexahydrate in air. The thermal decomposition of the salt in air led to NiO at about 1060 K. The kinetic parameters, the activation energyE and the preexponential factorA, and the thermodynamic parameters, the entropy, enthalpy and free energy of activation were evaluated for the dehydration and decomposition reactions. Tentative reaction mechanisms are suggested for each step of the thermal decomposition. 相似文献
11.
A. I. Kazakov Yu. I. Rubtsov G. B. Manelis L. P. Andrienko 《Russian Chemical Bulletin》1997,46(12):2015-2020
Kinetic regularities of thermal decomposition of dinitramide in aqueous and sulfuric acid solutions were studied in a wide
temperature range. The rate of the thermal decomposition of dinitramide was established to be determined by the rates of decomposition
of different forms of dinitramide as the acidity of the medium increases: first, N(NO2)− anions, then HN(NO2)2 molecules, and finally, protonated H2N(NO2)2
+ cations. The temperature dependences of the rate constants of the decomposition of N(NO2)− (k
an) and HN(NO2)2 (k′ac) and the equilibrium constant of dissociation of HN(NO2)2 (K
a) were determined:k
an=1.7·1017 exp(−20.5·103/T), s−1,k′ac=7.9·1016 exp(−16.1·103/T), s−1, andK
a=1.4·10 exp(−2.6·103/T). The temperature dependences of the decomposition rate constant of H2N(NO2)2
+ (k
d) and the equilibrium constant of the dissociation of H2N(NO2)2
+ (K
d) were estimated:k
d=1012 exp(−7.9·103/T), s−1 andK
d=1.1 exp(6.4·103/T). The kinetic and thermodynamic constants obtained make it possible to calculate the decomposition rate of dinitramide solutions
in a wide range of temperatures and acidities of the medium.
In this series of articles, we report the results of studies of the thermal decomposition of dinitramide performed in 1974–1978
and not published previously.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2129–2133, December, 1997. 相似文献
12.
Dana Bogdan J. P. Aycard Mohamed Hnach Elena Volanschi Mihaela Hillebrand V. Badescu N. Dragoe E. Segal 《Journal of Thermal Analysis and Calorimetry》1996,46(6):1729-1740
The thermal behaviour of some compounds derived from 5-phenylfuran-2,3-dione was studied. The thermoanalytical data relating to the decomposition steps and intermediates were completed with mass spectrometric analysis and infrared spectroscopy results. For some of the investigated reactions, the kinetic and structural data correlated satisfactorily. 相似文献
13.
X-ray single crystal diffraction demonstrates that in {[Pb2(HNTP)2(NTP)(CHZ)(H2O)2] · 2.5H2O}
n
(polymer, NTP = nitroterephthalate, CHZ = carbohydrazide), there are two kinds of Pb centers. By means of the bridging ligands–two
water, two CHZ and two NTP molecules, four Pb centers (two Pb1 and two Pb2) are joined together to form the rectangular grid,
and by the intense static electric interactions among the two O atoms of nitro groups in NTP, the extending two-dimensional
grids are linked together to form the three-dimensional frameworks. Thermal analyses DSC and TG-DTG have been performed on
the polymer to study its thermal decomposition mechanism and thermal kinetic properties.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
V. V. Nedel'ko A. V. Shastin B. L. Korsunskii N. V. Chukanov T. S. Larikova A. I. Kazakov 《Russian Chemical Bulletin》2005,54(7):1710-1714
Ditetrazol-5-ylamine (DTA) was synthesized from cyanuric chloride in four steps. The thermal decomposition of DTA in the solid
state was studied by thermogravimetry, volumetry, mass spectrometry, IR spectroscopy, and calorimetry. Under isothermal conditions
at 200–242 °C, thermal decomposition obeys the first order autocatalytic kinetics. The kinetic and activation parameters of
DTA decomposition were determined. The composition of gaseous reaction products and the structure of condensed residue were
studied. The thermal effect of thermal DTA decomposition is 281.4 kJ mol−1. The nitrogen content in a mixture of gaseous products formed by the reaction in a temperature interval of 200–242 °C exceeds
97 vol.%.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1660–1664, July, 2005. 相似文献
15.
R.B. MosM. Nasui T. Petrisor Jr.M.S. Gabor R. VargaL. Ciontea T. Petrisor 《Journal of Analytical and Applied Pyrolysis》2011,92(2):445-449
The present study reports on a novel barium acetato-propionate complex, obtained by the reaction of barium acetate with propionic acid, used as an oxide precursor with applications in superconducting thin films deposition. The molecular structure has been determined by X-ray diffraction on single crystals and demonstrated to be [Ba7(CH3CH2COO)10(CH3COO)4·5H2O]. The barium acetato-propionate is a three-dimensional channel-type polymer. The thermal decomposition of the barium precursor has been studied by simultaneous differential thermal analysis-thermogravimetry-mass spectrometry (DTA-TG-MS) in air at a heating rate of 10 °C/min. Based on these analyses, infrared spectroscopy was further used to characterize the precursor solution by the step-wise addition of the reagents. The X-ray diffraction on the precursor powder at different temperatures was performed. 相似文献
16.
《Journal of Coordination Chemistry》2012,65(14):2584-2592
An energetic coordination compound, Cu(HATZ)(PDA)(H2O) (HATZ?=?5-aminotetrazole, H2PDA?=?pyridine-2,6-dicarboxylic acid), has been synthesized and structurally characterized by single crystal X-ray diffraction. Copper(II) was coordinated by two oxygen atoms and nitrogen from PDA, one ring nitrogen of ATZ and one water to form a five-coordinate, distorted square-pyramidal structure. 3-D supramolecular architecture was formed by hydrogen bonding. Thermal decomposition of the compound was examined by DSC and TG-DTG analyses. The kinetic parameters of the first exothermic process of the compound were studied by Kissinger's and Ozawa–Doyle's methods. Sensitivity tests revealed that the compound was insensitive to mechanical stimuli. In addition, the compound was explored as additive to promote thermal decomposition of ammonium perchlorate by differential scanning calorimetry. 相似文献
17.
Zakariae Amghouz Santiago García-Granda Badredine Souhail Fa-nian Shi 《Journal of solid state chemistry》2009,182(12):3365-3373
New polymeric yttrium-succinates, Y2(C4H4O4)3(H2O)4·6H2O and Y2(C4H4O4)3(H2O)2, have been synthesized, and their structures (solved by single crystal XRD) are compared with that of Y2(C4H4O4)3(H2O)2·H2O. Three compounds were obtained as single phases, and their thermal behaviour is described. 相似文献
18.
This work presents results of research on thermal decomposition of nickel(II) sulfate(VI) hexahydrate in air and in helium
atmosphere. On the base of TG and XRD results a mechanism of thermal decomposition of NiSO4 hydrate was established. For calculations of kinetic parameters of the Arrhenius equation, the Coats-Redfern approximation
was applied. Choice of g(a) function and thus of a mechanism best describing given stage of decomposition was performed by
testing 12 kinetic models.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
E. Marceau D. Busatto G. Papin M. Michaud 《Journal of Thermal Analysis and Calorimetry》1996,46(1):27-37
The thermal decomposition of the only known antimony nitrate antimony(III) oxide hydroxide nitrate Sb4O4(OH)2(NO3)2, whose synthesis routes were reviewed and optimized was followed by TG-DTA under an argon flow, from room temperature up to 750°C. Chemical analysis (for hydrogen and nitrogen) performed on samples treated at different temperatures showed that an amorphous oxide hydroxide nitrate appeared first at 175°C, and decomposed into an amorphous oxide nitrate above 500°C. Above 700°C, Sb6O13 and traces of -Sb2O4 crystallized.Author to whom all correspondence should be addressed 相似文献
20.
Chen Donghua Yuan Yuhong Peng Zhenghe Jian Lihua Pan Qingcai Qin Zibin 《Thermochimica Acta》1998,320(1-2):291-295
Studies of the non-isothermal decomposition of M (mnt) (5-NO2-phen) (M=CoII, CuII, ZnII) were carried out by thermogravimetry. The thermal decomposition mechanisms and associated kinetics have been investigated. The kinetic parameters were obtained from an analysis of the TG–DTG curves by integral and differential methods. The most probable kinetic model functions were suggested by comparison of the kinetic parameters. Mathematical expressions for the kinetic compensation effect were derived. 相似文献