Kinetics of the Exothermic Decomposition Reaction of N-Methyl-N-nitro-2,2,2- trinitroethanamine

The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N-methyl-N-nitro-2,2,2-trinitroethanamine in a temperature-programmed mode have been investigated by means of differential scanning calorimetry (DSC).The kinetic equation of the exothermic decomposition process of the compound is proposed. The values of the apparent activation energy (Ea), pre-exponential factor (A), entropy of activation (ΔS^≠ ), enthalpy of activation (ΔH^≠ ), and free energy of activation (ΔG^≠ ) of this reaction and the critical temperature of thermal explosion of the compound are reported. Information is obtained on the mechanism of the initial stage of the thermal decomposition of the compound.     

The thermal decomposition of N,N-dimethyl-3-oxa-glutaramic 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 in-frared 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 ki-netic 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 1017.95s-1, respec-tively. The values of ΔS≠, ΔH≠ andΔG≠ of the reaction are 94.28 J-mol-1-K-1, 203.75 kJ-mol-1 and 155.75 kJ-mol-1, respectively.     

Thermal Degradation Kinetics of N,N＇-Di（diethoxythiophosphoryl）-1,4-phenylenediamine

The non-isothermal degradation kinetics of N,N＇-di（diethoxythiophosphoryl）-1,4-phenylenediamine in N2 was studied by TG-DTG techniques.The kinetic parameters,including the activation energy and pre-exponential factor of the degradation process for the title compound were calculated by means of the Kissinger and Flynn-Wall-Ozawa（FWO）method and the thermal degradation mechanism of the title compound was also studied with the Satava-Sestak methods.The results indicate that the activation energy and pre-exponential factor are 152.61 kJ/mol and 9.06×101 4s -1with the Kissinger method and 154.08 kJ/mol with the Flynn-Wall-Ozawa method,respectively.It has been shown that the degradation of the title compound follows a kinetic model of one-dimensional diffusion or parabolic law,the kinetic function is G（α）=α2and the reaction order is n=2.     

Thermal Behavior, Non-isothermal Decomposition Reaction Kinetics of Copper(Ⅱ) Salt of 4-Hydroxy-3,5-dinitropyridine and Its Application in Propellant

The thermal behavior and kinetic parameters of the major exothermic decomposition reaction of the title compound in a temperature-programmed mode were studied by means of TG-DTG and DSC. The critical temperature of thermal explosion was calculated. The effect of the title compound on the combustion characteristic of composition modifier double base propellant containing RDX was explored with a strand burner. The results show that the kinetic model function in differential forms, the apparent activation energy(Ea) and the pre-exponential factor(A) of the major exothermic decomposition reaction are 3(1-α)[-ln(1-α)]2/3, 190.56 kJ/mol and 1013.39 s-1, respectively. The critical temperature of thermal explosion of the compound is 353.08 ℃. The kinetic equation of the major exothermic decomposition process of the title compound at 0.1 MPa could be expressed as dα/dT=1014.65(1-α)[-ln(1-α)]2/3 e-2.2920×104/T. As an auxiliary catalyzer, the title compound can help the main catalyzer of lead salt of 4-hydroxy-3,5-dinitropyridine to accelerate the burning rate and reduce the pressure exponent of RDX-CMDB propellant.     

Synthesis and Thermal Behavior of 1,8-Dihydroxy- 4,5-dinitroanthraquinone Manganese Salt

A novel energetic combustion catalyst, 1,8-dihydroxy-4,5-dinitroanthraquinone manganese salt （DHDNEMn）, was synthesized by virtue of the metathesis reaction in a yield of 91%, and its structure was characterized by IR, element analysis and differential scanning calorimetry（DSC）. The thermal decomposition reaction kinetics was studied by means of different heating rate DSC. The results show that the apparent activation energy and pre-exponential factor of the exothermic decomposition reaction of DHDNEMn obtained by Kissinger＇s method are 162.3 kJ/mol and 1011.8 s^-1, respectively. The kinetic equation of major exothermic decomposition reaction of DHDNEMn is dα/dT= 10^118/β 2/5（1-α）[-ln（1-α）[-ln（1-α）]^3/5 exp（-1.623×10^5/RT）. The entropy of activation（△S^≠）, enthalpy of activation（△H^≠） and free energy of activation（A△G^≠） of the first thermal decomposition are -24.49 J·mol^-1·K^-1, 185.20 kJ/mol and 199.29 kJ/mol（T=575.5 K）, respectively. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） are 562.9 and 580.0 K, respectively. The above-mentioned information on the thermal behavior is quite useful for analyzing and evaluating the stability and thermal safety of DHDNEMn.     

Thermal Behavior,Nonisothermal Decomposition Reaction Kinetics of Mixed Ester Double-base Gun Propellants

The thermal decomposition behavior and nonisothermal reaction kinetics of the double-base gun propellants containing the mixed ester of triethyleneglycol dinitrate（TEGDN） and nitroglycerin（NG） were investigated by thermogravimetry（TG） and differential thermogravimetry（DTG）, and differential scanning calorimetry（DSC） under the high-pressure dynamic ambience. The results show that the thermal decomposition processes of the mixed nitric ester gun propellants have two mass-loss stages. Nitric ester evaporates and decomposes in the first stage, and nitrocellulose and centralite II（C2） decompose in the second stage. The mass loss, the DTG peak points, and the terminated temperatures of the two stages are changeable with the difference of the mass ratio of TEGDN to NG. There is only one obvious exothermic peak in the DSC curves under the different pressures. With the increase in the furnace pressure, the peak temperature decreases, and the decomposition heat increases. With the increase in the content of TEGDN, the decomposition heat decreases at 0.1 MPa and rises at high pressure. The variety of mass ratio of TEGDN to NG makes few effect on the exothermic peak temperatures in the DSC curves at different pressures. The kinetic equation of the main exothermal decomposition reaction of the gun propellant TG0601 was determined as： dα/dt=1021.59（1-α）3e-2.60×104/T. The reaction mechanism of the process can be classified as chemical reaction. The critical temperatures of the thermal explosion（Tbe and Tbp） obtained from the onset temperature（Te） and the peak temperature（Tp） are 456.46 and 473.40 K, respectively. ΔS≠, ΔH≠, and ΔG≠ of the decomposition reaction are 163.57 J·mol^-1·K^-1, 209.54 kJ·mol^-1, and 133.55 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.     

Differential and Integral Isoconversional Non‐linear Methods and Their Application to Energetic Materials. III. Non‐isothermal Decomposition Reaction Kinetics of Benzotrifuroxan

The thermal behaviour and decomposition reaction kinetics of benzotrifuroxan (BTF) were determined by TG and DSC techniques. The kinetic parameters of the exothermic decomposition reaction in a temperature programmed mode (the apparent activation energy Ea and pre-exponential factor A) were calculated by a single non-isothermal DSC curve. The E values calculated using the Kissinger and Flynn-Wall-Ozawa equations and integral isoconversional non-linear equations were used to check the validity of activation energy by a single non-isothermal DSC curve. The results show that the kinetic model function in integral form and the values of Ea and A of the decomposition reaction of BTFare , 109.95 kJ•mol－1 and 108.16 s－1, respectively. The values of ∆S≠, ∆H≠ and ∆G≠ of this reaction are －93.15 J•mol－1•K－1, 150.72 kJ•mol－1 and 153.15 kJ•mol－1, respectively. The critical temperature of thermal explosion of BTF is 257.33 ℃.     

果糖催化合成四氢苯并[b]吡喃衍生物:动力学和机理研究(英文)

Fructose was used as an efficient catalyst for three-component condensation reactions of aryl aldehydes,malononitrile,and dimedone in a mixture of EtOH and H_2O as green solvents.The advantages of this method are a short reaction time,high yields,low cost,easy accesses,and simple work-up.The mechanism of the synthesis of a derivative of 4H-tetrahydrobenzo[b]pyran was clarified using spectroscopic kinetic methods.The activation energy(Ea=65.34 kJ/mol)and related kinetic parameters(ΔG=69.14 kJ/mol,ΔS=20.99 J/(mol·K),andΔH=62.89 kJ/mol)were calculated,based on the effects of temperature,concentration,and solvent.The first step in the proposed mechanism was identified as the rate-determining step(k1),based on the steady-state approximation.     

Studies on Kinetics of Chlorination Reaction of Polyethylene

Through kinetic method, the reaction mechanism and the rate equations of chlorination of polyethylene are suggested in this paper. The rate of chlorination is second order with respect to the concentration of methylene remained and chlorine, respectively. Apparent changes in crystallinity during chlorination processes were determinated by differential scanning calorimetry(DSC). The mathematical model relating crystallinety with kinetic parameters and function of sequence length distribution are derived.     

Thermal Kinetics and Decomposition Mechanism of 1-Amino-1,2,3-triazolium Nitrate

The thermal decomposition kinetics of 1-amino-l,2,3-triazolium nitrate（ATZ-NO3） was investigated by non-isothermal TG-DTG at various heating rates（2,5,10,15 and 20 ℃/min）.The results show that the thermal decomposition of ATZ-NO3 consists of two stages corresponding to the losing of nitrate anion,substituent group and the splitting of triazole ring respectively.The kinetic triplets of the two stages were described by a three-step method.First,the differential Kissinger and intergral Ozawa methods were used to calculate the apparent activation energies（E） and pre-exponential factors（A） of the two decomposition stages.Second,two calculation methods（intergral （S）atava-（S）esták and differential Achar methods） were used to obtain several probable decomposition mechanism functions.Third,three judgment methods（average,double-extrapolation and Popescu methods） were used to confirm the most probable decomposition mechanism functions.Both reaction models of the two stages were randominto-nucleation and random-growth mechanisms with n=3/2 for the first stage and n=1/3,m=3 for the second stage.The kinetic equations for the two decomposition stages of ATZ-NO3 may be expressed as da/dt=1013.60·e-128970/RT（1-α）[-1n（1-α）]-1/2 and da/dt=1011.41·e-117370/RT（1-α）[-1n（1-α）]-2/3.The thermodynamic parameters including Gibbs free energy of activation（△G≠）,entropy of activation（△S≠） and enthalpy of activation（△H≠）,for the thermal decomposition reaction were also derived.     

Thermal Behavior, Non-isothermal Decomposition Reaction Kinetics of Copper（Ⅱ） Salt of 4-Hydroxy-3,5-dinitropyridine and Its Application in Propellant

IntroductionCopper( ) salt of4- hydroxy- 3,5 - dinitropy-ridine( 4 HDNPCu) is an energetic material contain-ing energetic_ NO2 groups,which can be used asan energetic auxiliary catalyzer substituting the in-ertia copper salt to improve the catalysis of themain catalyzer( lead salt) in propellant[1] .Thermalbehavior is one of the most important aspects af-fecting its catalytic efficiency for propellant.How-ever,its kinetic parameters of thermal decomposi-tion and its application in RDX- co…     

紫杉醇在二甲基亚砜中的溶解行为

用微热量热仪测量紫杉醇在二甲亚砜中的溶解焓。 得到了微分溶解热（Δ_difH_m）和积分溶解热（Δ_solH_m）,建立了热量与溶质的量之间的关系式。 并得到了紫杉醇在二甲亚砜中溶解过程的动力学方程：da/dt=2.92×10^-4×(1-a)^1.00,半衰期t_1/2=50.43 min,Δ_solH_m=32.67 kJ/mol以及Δ_solS_m=-204.93 J/(mol·K)。结果表明,利用微热量热法可以为药物半衰期的测定提供一种简便的方法,并可为紫杉醇的临床应用提供理论参考。     

Meso-2,3-二氰基-2,3-二苯基丁二酸二乙酯熔融相热异构化反应动力学及中间体EPR测定

测定了2,3-二氰基-2,β-二苯基丁二酸二乙酯meso-异构体熔融相的热异构化反应动力学及苯环对位为X(X=OCH₃,CH₃,H,Cl,NO₂)的相应二乙酯反应中间体自由基的EPR谱,自由基的结构由计算机模拟确定.结果表明,在实验温度范围内,平衡常数随温度的升高而降低.热力学数据为:ΔH_dl-meao= - 18.02 kJ/mol, ΔS_dl-meao= - 26.51 J/mol·K, ΔH^≠ = 151.78 kJ/mol, ΔS^≠ = 71.64 J/mol·K.反应机理是内消旋体的中心碳-碳键发生均裂,生成α-氰基-α-乙氧甲酰基-P-X取代苄基自由基,再重新结合时发生异构化,生成dl-异构体.     

Synthesis,crystal structure and thermal behavior of 4-amino-3,5-dinitropyrazole copper salt

A novel energetic combustion catalyst, 4-amino-3,S-dinitropyrazole copper salt （[Cu（adnp）2（H2O）2]）, was synthesized in a yield of 93.6% for the first time. The single crystal of [Cu（adnp）2（H2O）2] was determined by single crystal X-ray diffraction. It crystallizes in a triclinic system, space group p^-1 with crystal parameters a = 5.541（3） A, b = 7.926（4） A, c = 10.231（5） A,β = 101.372（8）°, V = 398.3（3） A3, Z = 1, μ = 1.467 mm^-1, F（0 0 0） = 243, and Dc = 2.000 g cm^-3. The thermal behavior and non-isothermal decomposition reaction kinetics of [Cu（adnp）2（H2O）2] were studied by means of different heating rate differential scanning calorimetry （DSC）. The kinetic equation of major exothermic decomposition reaction for [Cu（adnp）2（H2O）2] was obtained. The entropy of activation （△S≠）, enthalpy of activation （△H≠）, free energy of activation （△G≠）, the self-accelerating decomposition temperature （TSADT） and the critical temperature of thermal explosion （Tb） are 59.42 j mol^-1 K^-1, 169.5 kJ mol^-1, 1141.26 kJ mol ^-1 457.3 K and 468.1 K, respectively.     

Synthesis and Thermal Properties of Three Energetic Ion Salts of 3,6-Bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine

Three energetic ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine(BTATz), namely, methylamine salt(compound 1), ethylenediamine salt(compound 2), and diethylamine salt(compound 3), were synthesized and characterized by elemental analysis, Fourier transform infrared spectrometry, NMR spectroscopy, and ^13C NMR spectroscopy. The crystal structure of compound 1 was determined by single-crystal X-ray crystallography, and structural analysis revealed that it belonged to the monoclinic system with P21/c space group. In addition, the thermal behavior of the three compounds was studied by differential scanning calorimetry and thermogravimetry techniques. The thermal decomposition peak temperatures of the compounds were 574.89, 545.60, and 606.72 K, indicating that the three ion salts exhibited good thermal stability. Tlie kinetic mechanism equations of the main decomposition process and the entropy of activation(△S^≠), enthalpy of activation(△H^≠), and Gibbs free energy of activation(△G^≠) of the three compounds were also obtained. Moreover, the thermal safety of the compounds was evaluated by the values of the self^accelerated decomposition temperature(Tsadt)5 thermal ignition temperature(TTIT), and critical temperature of thermal explosion(7b). The results showed that all the compounds demonstrated good thermal safety, and the thermal safety of compound 3 was better than that of the others.     

Ni-Mg复合催化剂催化裂解CH_4制氢动力学研究

基于定温热重实验,建立了甲烷催化裂解反应动力学模型和催化剂表面积炭失活动力学模型。其中,甲烷催化裂解动力学模型将初始产氢速率视为催化剂未积炭条件下的动力学基础数据;催化剂表面积炭失活动力学则基于甲烷催化裂解速率的降低。实验使用Ni-Mg复合催化剂,分别在535、585、635℃,甲烷分压10~4、2×10~4、3×10~4Pa条件下展开甲烷催化裂解动力学特性研究。结果表明,甲烷催化裂解的反应级数为0.5,活化能为82 k J/mol;Ni-Mg复合催化剂反应失活级数为0.5,催化剂失活活化能为118 k J/mol。实验条件下均制得了多壁碳纳米管。     

Kinetics and Thermodynamics of Adsorption of VB12 onto Mesoporous Carbon Coated with PMMA

Ordered mesoporous carbons CMK-3, CMK-1 coated with poly(methyl methacrylate)(PMMA)(CMK-3- PMMA and CMK-1-PMMA) and pristine mesoporous carbons CMK-3, CMK-1 were employed to adsorb vitamin B12(VB12) from water solution. Adsorption isotherm and kinetics of adsorption were investigated via batch experi- ments. It was found that the adsorption capacity of VB12 at 30, 40 and 50 °C can reach 688.2, 572.4 and 428.7 mg/g, respectively. The adsorption isotherm can be described by Langmuir model. The pseudo first- and second-order kinetic models were employed to fit the dynamic adsorption. It was found that the dynamic adsorption follows the pseudo second-order model. The thermodynamic equilibrium coefficients obtained at different temperatures were used to evaluate the thermodynamic constants ΔG0, ΔH0 and ΔS0. The negative value of Gibbs free energy, ΔG0 indicates that the adsorption occurred via a spontaneous process. The increase in the value of –ΔG0 with increasing temperature indicates that higher temperatures were favourable to the sorption process. The enthalpy values of ΔH040 kJ/mol(66.36 kJ/mol and 56.43 kJ/mol) for CMK-3-PMMA and CMK-1-PMMA confirm that chemisorption were involved in the adsorption process. This is consistent with the IR spectra and is another evidence for the formation of hydrogen bond between PMMA in the pore of CMK-3 and VB12.     

电子陶瓷粉BaTiO3的液相合成技术(Ⅲ)──前驱体草酸氧钛钡的热分解反应动力学研究

以Brodio线性化简单图解法对前驱体草酸氧钛钡热分解过程中三段动力学参数进行了计算。结果表明,三段热分解的反应级数分别为2、2和0,活化能为96.8、165.1和172.2kJ/mol,频率因子为1.03×10¹¹、5.64×10⁸和2.63×10⁶s^-1.由热分解动力学参数优化热处理工艺制得高纯超细BaTiO₃粉体。