Thermal Behavior of 2‐(Dinitromethylene)‐1,3‐diazacyclopentane

A new compound, 2‐(dinitromethylene)‐1,3‐diazacyclopentane (DNDZ), was prepared by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) with 1,2‐diaminoethane in N‐methylpyrrolidone (NMP). Thermal decomposition of DNDZ was studied under non‐isothermal conditions by DSC, TG/DTG methods, and the enthalpy, apparent activation energy and pre‐exponential factor of the exothermic decomposition reaction were obtained as 317.13 kJ·mol^?1, 269.7 kJ·mol^?1 and 10^24.51 s^?1, respectively. The critical temperature of thermal explosion was 261.04°C. Specific heat capacity of DNDZ was determined with a micro‐DSC method and a theoretical calculation method, and the molar heat capacity was 205.41 J·mol^?1·K^?1 at 298.15 K. Adiabatic time‐to‐explosion was calculated to be a certain value between 263–289 s. DNDZ has higher thermal stability than FOX‐7.     

Preparation and Study of Thermal Decomposition Mechanism of Zn(Thr)(AcO)_2·2H_2O

Introduction -Amino acids as additive have a wide application in medicines, foodstuff and cosmetics.1-3 The synthetic methods of amino acid have been reviewed.4,5 The solu-bility property of Zn(AcO)2-Thr-H2O (Thr=Threonine) system at 298.15 K has been investigated by the semimicro-phase equilibrium method, in which the phase region of the complex did not exist.6 The prepara-tion of Zn(Thr)SO4H2O was reported in Ref. 7∶3 times volume of acetone relative to that of water was added into t…     

Kinetics and Mechanism of the Exothermic First-stage Decomposition Reaction of Dinitroglycoluril

Introduction Dinitroglycoluril (DINGU) is a typical cyclourea nitramine. Its crystal density is 1.94 gcm-3. The detonation velocity corresponding to =1.94 gcm-3 is about 8450 ms-1. Its sensitivity to impact is better than that of cyclotrimethylenetrinitramine. It has the potential for possible use as high explosive from the point of view of the above-mentioned high performance. Its preparation,1-4 properties1-4 and hydrolytic behavior4 have been reported. In the present paper, we report i…     

Thermal Behavior of N,N＇Bis[N-（2,2,2-trinitroethyl）-N-nitro]ethylenediamine

The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N‐N‐bis[N‐(2,2,2‐tri‐nitroethyl)‐N‐nitro]ethylenediamine in a temperature‐programmed mode have been investigated by means of differential scanning calorimetry (DSC). The results show that kinetic model function in differential form, apparent activation energy E_a and pre‐exponential factor A of this reaction are 3(1 ‐α)^2/3, 203.67 kJ·mol^?1 and 10^20.61s^?1, respectively. The critical temperature of thermal explosion of the compound is 182.2 °C. The values of ΔS^≠ ΔH^≠ and ΔG^≠ of this reaction are 143.3 J·mol^?1·K^?1, 199.5 kJ·mol^?1 and 135.5 kJ·mol^?1, respectively.     

鬼臼毒素及其衍生物热分解反应的动力学研究

The thermal behavior and thermal decomposition kinetic parameters of podophyllotoxin （1） and 4 derivatives, picropodophyllin （2）, deoxypodophyllotoxin （3）, fl-apopicropodophyllin （4）, podophyllotoxone （5） in a temperature-programmed mode have been investigated by means of DSC and TG-DTG. The kinetic model functions in differential and integral forms of the thermal decomposition reactions mentioned above for first stage were established. The kinetic parameters of the apparent activation energy Ea and per-exponential factor A were obtained from analy- sis of the TG-DTG curves by integral and differential methods. The most probable kinetic model function of the decomposition reaction in differential form was （1- a）^2 for compounds 1-3,2/3·a^-1/2 for compound 4 and 1/2（1-a）·[-In（1-a）]^-1 for compound 5. The values of Ea indicated that the reactivity of compounds 1-5was increased in the order： 5〈4〈2〈1〈3. The values of the entropy of activation △S^≠, enthalpy of activation △H^≠ and free energy of activation △G^≠ of the reactions were estimated. The values of △G^≠ indicated that the thermal stability of compounds 1-3 with the samef（a） was increased in the order： 2〈3〈1.     

Synthesis and Characterization of a New Energetic Salt based on Dinitramide

The development of new ionic salt as green propellants is one of intense investigations to replace toxic N, N′‐dimethylhydrazine. A new energetic salt N, N′,N′′‐tri(propan‐2‐ylidene)methanetriamium dinitramide (NTAGDN) based on dinitramide was synthesized by reacting silver dinitramide with triaminoguanidinium chloride. The structure of this new energetic salt was confirmed by single‐crystal X‐ray diffraction, elemental analysis, Fourier transform infrared spectrometry, ultraviolet‐visible spectrophotometry, and nuclear magnetic resonance spectroscopy. NTAGDN crystallizes in the orthorhombic space group R$\bar{3}$ . Thermal decomposition was studied by differential scanning calorimetry, differential thermal analysis, and thermogravimetric tandem infrared spectrometry. Results indicated that NTAGDN exhibited excellent resistance to thermal decompositions of up to 470 K and incurred an 80.54 % mass loss between 450 and 523 K via exothermic decomposition. The kinetic parameters of NTAGDN thermal decomposition were also obtained from the differential thermal analysis data by Kissinger's method with E_a = 125.46 kJ · mol^–1. Moreover, based on the Kamlet‐Jacobs formula, the detonation velocity and detonation pressure of NTAGDN were calculated as 6.3 km · s^–1 and 15 GPa, respectively.     

The thermal decomposition of N,N-dimethyl-3-oxaglutaramic acid and the kinetics of its second-stage thermal decomposition reaction

N,N-dimethyl-3-oxa-glutaramic acid was purified and characterized by ¹H-NMR, Fourier transform infrared spectroscopy (FT-IR) and elemental analysis. The thermal decomposition of the title compound was studied by means of thermogravimetry differential thermogravimetry (TG-DTG) and FT-IR. The kinetic parameters of its second-stage decomposition reaction were calculated and the decomposition mechanism was discussed. The kinetic model function in a differential form, apparent activation energy and pre-exponential constant of the reaction are 3/2 [(1?α)^1/3?1]^?1, 203.75 kJ·mol^?1 and 10^17.95s^?1, respectively. The values of ΔS ^≠, ΔH ^≠ and ΔG ^≠ of the reaction are 94.28 J·mol^?1·K^?1, 203.75 kJ·mol^?1 and 155.75 kJ·mol^?1, respectively.     

CoC2O4·2H2O在空气中的热分解动力学研究

纳米Co3O4具有尖晶石结构,Co3 占据八面体位,具有较高的晶体场稳定化能,在空气中低于800℃时十分稳定,是优良的催化材料[1]。Co3O4还可以作为高比能锂离子电池负极材料具有非常好的电化学活性,充放电容量高达960m A h·g-1。纳米Co3O4在紫外、可见及近红外区域都有良好的吸收效果,因此,在隐身技术、保温节能技术等领域具有潜在的应用前景。所以,Co3O4超细粉体的制备和应用研究具有十分重要的意义。我们合成了草酸盐先驱物制备纳米Co3O4用作隐身材料,因此对先驱物的热分解过程研究是十分必要的。热分析方法在了解先驱物热分解反应的物理…     

The study of thermal decomposition kinetics of zinc oxide formation from zinc oxalate dihydrate

This study is devoted to the thermal decomposition of ZnC₂O₄·2H₂O, which was synthesized by solid-state reaction using C₂H₂O₄·2H₂O and Zn(CH₃COO)₂·2H₂O as raw materials. The initial samples and the final solid thermal decomposition products were characterized by Fourier transform infrared and X-ray diffraction. The particle size of the products was observed by transmission electron microscopy. The thermal decomposition behavior was investigated by thermogravimetry, derivative thermogravimetric and differential thermal analysis. Experimental results show that the thermal decomposition reaction includes two stages: dehydration and decomposition, with nanostructured ZnO as the final solid product. The Ozawa integral method along with Coats–Redfern integral method was used to determine the kinetic model and kinetic parameters of the second thermal decomposition stage of ZnC₂O₄·2H₂O. After calculation and comparison, the decomposition conforms to the nucleation and growth model and the physical interpretation is summarized. The activation energy and the kinetic mechanism function are determined to be 119.7 kJ mol^?1 and G(α) = ?ln(1 – α)^1/2, respectively.     

Thermal studies and spectral characterization of the chelate of bis-(η5-cyclopentadienyl titanium(IV) with salicylidene-4-methylaniline

A new chelate (η⁵-C₅H₅)₂Ti(SB)₂, whereSB=O, N donor Schiff base salicylidene-4-methylaniline, was synthesized. The course of thermal degradation of the chelate was studied by thermogravimetric (TG) and differential thermal analysis (DTA) under dynamic conditions of temperature. The order of the thermal decomposition reaction and energy of activation was calculated from TG curve while from DTA curve the change in enthalpy was calculated. Evaluation of the kinetic parameters was performed by Coats-Redfern as well as Piloyan-Novikova methods which gaven=1, ΔH=1.114 kJ·mol^?1, ΔE=27.01 kJ·mol^?1, ΔS=?340.12 kJ·mol^?1·K^?1 andn=1, ΔH=1.114 kJ·mol^?1, ΔE=20.01 kJ·mol^?1, ΔS=?342.60 kJ·mol^?1·K^?1, respectively. The chelate was also characterized on the basis of different spectral studies viz. conductance, molecular weight, IR, UV-visible and¹H NMR, which enabled to propose an octahedral structure to the chelate.     

Thermal behavior and thermal safety on 3,3-dinitroazetidinium salt of perchloric acid

3,3-Dinitroazetidinium (DNAZ) salt of perchloric acid (DNAZ·HClO₄) was prepared, it was characterized by the elemental analysis, IR, NMR, and a X-ray diffractometer. The thermal behavior and decomposition reaction kinetics of DNAZ·HClO₄ were investigated under a non-isothermal condition by DSC and TG/DTG techniques. The results show that the thermal decomposition process of DNAZ·HClO₄ has two mass loss stages. The kinetic model function in differential form, the value of apparent activation energy (E _a) and pre-exponential factor (A) of the exothermic decomposition reaction of DNAZ·HClO₄ are f(α) = (1 − α)⁻¹/2, 156.47 kJ mol⁻¹, and 10^15.12 s⁻¹, respectively. The critical temperature of thermal explosion is 188.5 °C. The values of ΔS ^≠, ΔH ^≠, and ΔG ^≠of this reaction are 42.26 J mol⁻¹ K⁻¹, 154.44 kJ mol⁻¹, and 135.42 kJ mol⁻¹, respectively. The specific heat capacity of DNAZ·HClO₄ was determined with a continuous C _p mode of microcalorimeter. Using the relationship between C _p and T and the thermal decomposition parameters, the time of the thermal decomposition from initiation to thermal explosion (adiabatic time-to-explosion) was evaluated as 14.2 s.     

Thermal Behaviors of 2‐(Dinitromethylene)‐1,3‐diazacycloheptane (DNDH)

2‐(Dinitromethylene)‐1,3‐diazacycloheptane (DNDH) was prepared by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) with 1,4‐diaminoethane in NMP. Thermal decomposition behavior of DNDH was studied under the non‐isothermal conditions with DSC method, and presents only one intensely exothermic decomposition process. The kinetic equation of the decomposition reaction is dα/dT=10^33.88×3α^2/3exp(−3.353×10⁵/RT)/β. The critical temperature of thermal explosion is 215.97°C. Specific heat capacity of DNDH was studied with micro‐DSC method and theoretical calculation method, and the molar heat capacity is 215.40 J·mol⁻¹·K⁻¹ at 298.15 K. Adiabatic time‐to‐explosion was calculated to be 92.07 s. DNDH has same thermal stability to FOX‐7.     

Kinetic Study on the Exothermic Decomposition Reaction of 2,4,6,8-Tetranitro-2,4,6,8-tetraazabicyclo[3,3,1]onan-3,7-dione

Introduction 2,4,6,8-Tetranitro-2,4,6,8-tetraazabicyclo[3,3,1]nonan- 3,7-dione (1) is a novel energetic cyclourea nitramine containing four —NO2 groups (Figure 1). The detona-tion velocity corresponding to =1.93 gcm-3 is 9034 ms-1. It is the potential high explosive. Its preparation,1 properties1 and hydrolytic behavior2 have been reported. Thermal behavior is one of the most important aspects of the compound in practical application. However, its kinetic parameters of thermal decomposition…     

In situ thermo-TOF-SIMS study of thermal decomposition of zinc acetate dihydrate

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used for an in situ thermal decomposition study of Zn(CH₃COO)₂·2H₂O forming ZnO nanoparticles. TOF-SIMS spectra were recorded at regular temperature intervals of 25 °C in positive and negative detection modes in a dynamic thermal process. Controlled heating (5 °C min⁻¹) of Zn(CH₃COO)₂·2H₂O was also carried out using thermogravimetric analysis (TGA) in an oxygen atmosphere (20 ml min⁻¹). Nearly spherical ZnO nanoparticles with no agglomeration and a narrow size distribution (diameter ∼50 nm) were observed, which were characterized using scanning electron microscopy, transmission electron microscopy and x-ray diffraction. In situ thermo-TOF-SIMS was used to monitor the ⁶⁴Zn⁺ and ⁶⁶Zn⁺ ion abundances as a function of temperature, which showed a similar profile to that observed for weight loss in TGA during decomposition. Based on the experimental results, a possible decomposition mechanism for the formation of ZnO is proposed. Copyright © 2004 John Wiley & Sons, Ltd.     

Mechanism and kinetics of 2-chlorophenol decomposition using coupled ultrasound and electrocatalysis

A coupled ultrasound/electrocatalysis(US/EC) process was used to enhance the decomposition effi-ciency of organics.The synergetic kinetics and the mechanism of 2-chlorophenol(2-CP) decomposi-tion with coupled US/EC were studied.It was found that in a US/EC process 2-CP is attacked by active radicals(such as hydroxyl radicals) to form 2-chloro-p-benzoquinone,and the latter is oxidized to simple organic acids when the ring is opened.The enhancement factor expressed by the apparent rate constant of 2-CP decomposition with coupled US/EC is 1.324 at a current density of 20 mA·cm-2,an ultrasonic frequency of 20 kHz,an ultrasonic intensity of 0.27 W·cm-2,and a 2-CP initial concentration of 200 mg·L-1,which means that a synergetic effect exists.A model derived from Langmuir adsorption theory of solid surface and reaction kinetics equations can describe exactly the decomposition of 2-CP with coupled US/EC.The numerical values are in good agreement with the experimental data.The model parameters are associated with reaction conditions.     

Thermal Decomposition Kinetics of Triethylene Glycol Dinitrate

Introduction Triethylene glycol dinitrate (TEGDN) is a novel en-ergetic material containing two groups of NO2, which can be used as an energetic plasticizer ingredient in propellants because of its excellent proformance.1 It exhibits lower impact sensitivity, better thermostability, weaker poisonousness and volatility, and stronger effec-tiveness of plasticizing cellulose nitrate than nitroglyc-erine (NG). As a new plasticizer TEGDN has good ap-plication prospects in the near future. The…     

Competition between thermal decomposition and hydrolysis of 2,2'-azobis(2-amidinopropane) in aqueous solution

The thermal decomposition and hydrolysis of 2,2′-azobis(2-amidinopropane) were examined as functions of pH. The rate of decomposition decreased with increasing pH. The specific rates at 60°C were 3.85 × 10^?5 1/sec at pH 0.90 and 2.5 × 10^?5 1 see at pH ≥ 8.5. The hydrolysis in alkaline solution yielded 2,2′-azobis(2-carbamylpropane) which was stable to thermal decomposition. The relation between the specific rate of hydrolysis k_h′ and the concentration of hydroxyl ion was obtained as k_h′ = 4.0 × 10^?2 [OH]^0.50 1/sec at 60°C. In alkaline solution, the rate of hydrolysis was considerably larger than that of thermal decomposition. A mechanism for this hydrolysis is propesed.     

Thermal studies on thorium(IV) complexes of 1-butyl-1-methylpiperazinium iodide

Thorium(IV) complexes of the type Th(NO₃)₄·3L·2C₂H₅OH, Th(SCN)₄·L·C₂H₅OH and Th(SO₄)₂·2L·2C₂H₅OH (L=1-butyl-1-methylpiperazinium iodide(I) have been synthesised. From thermogravimetric (TG) curves, the decomposition pattern of the compounds has been analysed. The order, activation energy and apparent activation entropy of the thermal decomposition reaction have been elucidated. The heat of reaction has been calculated from differential thermal analysis (DTA) studies.     

Synthesis,Crystal Structure,and Thermal Behavior of a Novel Insensitive Energetic Cocrystal Composed of 3,3′‐Bis(1,2,4‐oxadiazole)‐5,5′‐dione and 4‐Amino‐1,2,4‐triazole

A novel insensitive energetic cocrystal consisting of 3,3′‐bis(1,2,4‐oxadiazole)‐5,5′‐dione and 4‐amino‐1,2,4‐triazole in a 1:2 molar ratio was prepared and characterized. The structure of this cocrystal was characterized by single‐crystal X‐ray diffraction. The crystal structure of the cocrystal is a monoclinic system with P1 space group. Properties of the cocrystal studied included thermal decomposition and detonation performance. This cocrystal has a crystal density of 1.689 g · cm^–3 at 173 K and good detonation performance (D = 6940 m · s^–1, P = 20.9 GPa). Moreover, measured impact and friction sensitivities (IS > 40 J, FS > 360 N) show that it can be classified as an insensitive energetic material. Its thermodynamic properties indicate that it has moderate thermal stability with a sharp exothermic peak (244 °C, 5 K · min^–1) and a high critical temperature of thermal explosion (523 K). In view of the observations above, it may serve as a promising alternative to known explosives such as TNT.     

Synthesis, structure analysis and thermodynamics of [Ni(H2O)4(TO)2](NO3)2·2H2O (TO = 1,2,4-triazole-5-one)

A novel complex [Ni(H₂O)₄(TO)₂](NO₃)₂·2H₂O (TO = 1,2,4-triazole-5-one) was synthesized and structurally characterized by X-ray crystal diffraction analysis. The decomposition reaction kinetic of the complex was studied using TG-DTG. A multiple heating rate method was utilized to determine the apparent activation energy (E _a) and pre-exponential constant (A) of the former two decomposition stages, and the values are 109.2 kJ mol^?1, 10^13.80 s^?1; 108.0 kJ mol^?1, 10^23.23 s^?1, respectively. The critical temperature of thermal explosion, the entropy of activation (ΔS ^≠), enthalpy of activation (ΔH ^≠) and the free energy of activation (ΔG ^≠) of the initial two decomposition stages of the complex were also calculated. The standard enthalpy of formation of the new complex was determined as being ?1464.55 ± 1.70 kJ mol^?1 by a rotating-bomb calorimeter.