3-硝基邻苯二甲酸锆的制备﹑热分解机理及非等温反应动力学

用3-硝基邻苯二甲酸、氢氧化钠和硝酸氧锆为原料, 制备了3-硝基邻苯二甲酸锆, 采用元素分析、X射线荧光衍射和FT-IR对其结构进行了表征. 用TG-DTG以及变温固相原位反应池/傅里叶变换红外光谱(RSFT-IR)联用技术研究了3-硝基邻苯二甲酸锆的热分解机理, 对主分解反应的DTG峰进行了数学处理, 计算得到了动力学参数和动力学方程. 结果表明, 3-硝基邻苯二甲酸锆的分解反应总共有4个阶段, 其中主分解反应发生在第2阶段, 主分解反应的表观活化能Ea与指前因子A分别为158.84 kJ·mol-1和10^9.85 s-1, 主分解阶段的反应机理服从一级Mample法则, 主分解反应的动力学方程为dα/dt=10^9.85(1-α)e^-1.91×10⁴/T.     

Synthesis and characterization of oxazolone complexes with Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) in different counterions

Oxazolone forms (1:1) complexes with Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ chlorides, as well as forms (1:1) complexes with Co²⁺ and Cu²⁺ acetates. All the complexes are found to be non-electrolytes in DMF; tetrahedral, square-planar and octahedral structures are assigned to them based on electronic and magnetic data. IR studies reveal that the complexes are formed by donating the lone-pair electron from O and N atoms to the metal ion. The thermal decomposition of the [ML·mX·nH₂O]_y·H₂O chelates was studied by TG–DTA techniques. The mechanism of the decomposition has been established from TG–DTA data. The kinetic parameters, activation energy (E_a) and pre-exponential factor (A), were calculated from TG curves using Coats and Redfern method. Relative thermal stabilities of the chelates have been evaluated on the basis of these parameters.     

Synthesis, characterization and thermal investigation of M[M(C2O4)3]·xH2O (x=4 for M=Cr(III); x=2 for M=Sb(III) and x=9 for M=La(III))

The complexes, M[M(C₂O₄)₃]·xH₂ O, where x=4 for M=Cr(III), x=2 for M=Sb(III) and x=9 for M=La(III) have been synthesized and their thermal stability was investigated. The complexes were characterized by elemental analysis, IR and electronic spectral data, conductivity measurement and powder X-ray diffraction (XRD) studies. The chromium(III)tris(oxalato)chromate(III)tetrahydrate (COT), Cr[Cr(C₂ O₄)₃]·4H₂O, released water in a stepwise fashion. Removal of the last trace of water was accompanied by a partial decomposition of the oxalate group. Thermal investigation using TG, DTG and DTA techniques in air produced Cr₂O₃ at 858°C through the intermediate formation of Cr₂O₃ and CrC₂O₄ at around 460°C. While DSC study in nitrogen up to 670°C produced a mixture of Cr₂O₃ and CrC₂O₄. In antimony(III)tris(oxalato)antimonate(III)dihydrate (AOD), Sb[Sb(C₂O₄)₃]·3H₂O the dehydration took place during the decomposition of precursor at 170–290°C and finally at ca. 610°C Sb₂ O₅ along with trace amounts of Sb₂O₄ were produced. Trace amount of Sb₂O₃ and Sb along with Sb₂O is proposed as the end product at 670°C of AOD in nitrogen. The oxide La₂O₃ is formed at 838°C from the study with TG, DTG and DTA in air of lanthanum(III)tris(oxalato)lanthanum(III)nonahydrate (LON), La[La(C₂O₄)₃]·9H₂O. Intermediate dioxycarbonate, La₂O₂CO₃ was generated at 526°C prior to its decomposition to lanthanum oxide in air; whereas in N₂ the formation of La₂(CO₃)₃ at 651°C was proposed. The thermal parameters have been evaluated for each step of the dehydration and decomposition of COT, AOD and LON using five non-mechanistic equations i.e. Flynn and Wall, Freeman and Carroll, Modified Freeman and Carroll, Coats–Redfern and MacCallum–Tanner equations. Kinetic parameters, such as, E^*, k_o, ΔH^*, ΔS^* etc. were also supplemented by DSC studies in nitrogen for all the three complexes. Some of the intermediate species have been identified by analytical and powder XRD studies. Tentative schemes has been proposed for the decomposition of all three compounds in air and nitrogen.     

Kinetics and Mechanism of Exothermic First-stage Decomposition Reaction of 2,6-Bis （2,2,2-trinitroethyl）glycoluril

The thermal behavior, mechanism and kinetic parameters of the exothermic first-stage decomposition of the title compound in a temperature-programmed mode were investigated by means of DSC, TG-DTG and IR. The reaction mechanism was proposed. The kinetic model function in differential form, apparent activation energy(Ea) and pre-exponential factor(A) of this reaction are (3/2)(1-a)[-ln(1-a)]1/3, 185.52 kJ/mol and 1017.78 s-1, respectively. The critical temperature of the thermal explosion of the compound is 201.30 ℃. The values of ΔS≠, ΔH≠ and ΔG≠ of this reaction are 72.46 J/(mol · K), 175.1 kJ/mol and 141.50 kJ/mol, respectively.     

Non-isothermal Decomposition Kinetics of K(AHDNE)

The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro- ethylene potassium salt[K(AHDNE)] were studied under the non-isothermal conditions by different scanning calorimeter(DSC) method. The thermal behavior of K(AHDNE) presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=(10^19.63/β)3(1-α)[-ln(1-α)]^2/3exp(-1.862× 10⁵/RT). The self-accelerating decomposition temperature(T_SADT) and critical temperature of thermal explosion(T_b) of K(AHDNE) are 162.5 and 171.4 ℃, respectively. K(AHDNE) has higher thermal stability than AHDNE.     

3，5-二硝基水杨酸铈的制备﹑热分解机理及非等温反应动力学

用3,5-二硝基水杨酸和硝酸铈为原料,制备了3,5-二硝基水杨酸铈(CeDNS),采用元素分析、X射线荧光光谱和FTIR对其进行了表征。用TG和DSC以及变温固相原位反应池/傅立叶变换红外光谱(RS-FTIR)联用技术研究了3,5-二硝基水杨酸铈的热分解机理,对主放热反应的DSC峰进行了数学处理,计算得到了动力学参数和动力学方程。结果表明,3,5-二硝基水杨酸铈的分解反应共有3个阶段,其中包括一个脱水吸热过程和一个主放热过程,主分解反应发生在第2阶段,主分解反应的表观活化能E_a与指前因子A分别为：159.17 kJ·mol^-1 和10^11.33 s^-1,主分解阶段的反应机理服从Avrami-Erofeev方程(n=1/4),主分解反应的动力学方程为：dα/dt=10^11.33×4(1-α)[-ln(1-α)]^3/4e^-1.92×104/T。     

M(CO)4 (M = Mo or W) complexes of 2,6-bis(methylthiomethyl)pyridine (L) and 2,6-bis(p-tolylthiomethyl)pyridine (L): a dynamic NMR study

The hybrid S/N/S donor ligands 2,6-bis(methylthiomethyl)pyridine (L¹) and 2,6-bis(p-tolylthiomethyl)pyridine (L²) react with the [M(CO)₅(THF)] (M = Mo or W) compounds to form complexes of general formula [M(CO)₄L] (M = Mo, L = L²; M = W, L = L¹ or L²), where both L¹ and L² act in a S/N bidentate chelate fashion. In solution, these complexes undergo three fluxional processes, viz. inversion at the coordinated S atom, S¹–S² switching, and combined inversion and S¹–S² switching, leading to an interconversion of the four possible permutational isomers. Energy barriers for all three processes have been evaluated by standard one-dimensional band-shape analysis techniques. The mechanism of the S¹–S² switch is discussed.     

Thermal decomposition of poly(1,4-dioxan-2-one)

To evaluate the feasibility of poly(1,4-dioxan-2-one) (PPDO) as a feed stock recycling material, the pyrolysis kinetics of PPDO were investigated. The pyrolysis of PPDO exclusively resulted in the distillation of 1,4-dioxan-2-one (PDO). From thermogravimetric measurements conducted at different heating rates, the kinetic parameters of the pyrolysis: activation energy, E_a=127 kJ mol⁻¹; order of reaction, n=0; and pre-exponential factor, A=2.3×10⁹ s⁻¹, were estimated by plural analytical methods. The estimates show that the decomposition of PPDO proceeds by unzipping depolymerization as main reaction and random degradation process with lower E_a and A values. Equivalent isothermal degradation curves calculated from the thermogravimetric curves were supported by experimental isothermal degradation data. The calculation that PPDO is converted smoothly into PDO at 270°C agrees with the reported ceiling temperature of PPDO.     

三维无溶剂含能Ag-MOF的制备、热分解动力学及爆炸性能

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 (T_e = 619.1 K, T_p = 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 (E_a = 272.1 kJ·mol⁻¹, E_o = 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 (T_b = 607.1 K), and self-accelerating decomposition temperature (T_SADT = 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.     

Analysis of thermodynamic and kinetic stabilities in the thermal decomposition of the trinuclear μ-oxoacetates Fe 2 III MIIO(CH3OO)6(H2O)5, with M=Mn,Fe, Co or Ni

The thermal analysis of acetate clusters of general formula [Fe ₂ ^III M^IIO(CH₃COO)₆(H₂O)₃]·2H₂O, with M=Mn, Fe, Co or Ni, was performed in dynamic and quasi-isothermal regimes. The thermal decompositions of these compounds proceed in the interval 40–310° and consist of two endothermic and three exothermic stages. Dependence on the nature of the transition metal M is evidenced most explicitly in the parameters of the second stage, proceeding in the interval 103–170°. For this stage the sequences of thermodynamic stability and kinetic stability were established. The effect of the nature of the metal on the thermodynamic and kinetic parameters of the thermal decomposition processes involving the heteronuclear acetates was analyzed. Mechanisms for the first two stages of thermal decomposition are suggested.     

Thermal decomposition of potassium,rubidium and caesium fluoroantimonates(III)

The thermal decomposition of crystalline complexes of the types M₂[SbF₅], M[SbF₄], M[Sb₂F₇] and M[Sb₄F₁₃] (where M = K, Rb, Cs) was studied. Crystals were prepared by slight modifications of the methods described in the literature. On the basis of the results of thermal analyses the mechanisms of thermal decomposition were proposed. From thermogravimetric curves kinetic parameters were calculated using the methods of Coats and Redfern and Zsako. A comparison was made of the thermal stabilities in the light of available structural data.     

聚羟基丁酸-戊酸的非等温热分解反应动力学

用非等温TG-DTA技术, 在5.0、10.0、15.0和20.0 K•min^-1线性升温条件下, 研究聚羟基丁酸-戊酸(PHBV)的热分解反应动力学. 结果表明, 分解过程分三个阶段：分解初期、分解中期和分解后期. 分解初期的机理函数为Avrami-Erofeev方程(n=1/2), 对应随机成核和随后生长机理, 表观活化能E_a(β→0)为69.44 kJ•mol^-1, 指前因子A(β→0)为106.27 s^-1；分解中期的机理函数为Avrami-Erofeev方程(n =2/5), 对应随机成核和随后生长机理, 表观活化能Ea(β→0)为117.64 kJ•mol^-1, 指前因子A(β→0)为10^11.48 s^-1；分解后期的机理函数为Mampel Power法则(n=1/3), 对应机理为幂函数法则, 表观活化能Ea(β→0)为116.64 kJ•mol^-1, 指前因子A(β→0)为10^8.68 s^-1.     

噻吩在M(111)(M=Pd,Pt,Au)表面的吸附(英文)

采用密度泛函理论(DFT),选取DMol3程序模块,对噻吩在M(111)(M=Pd,Pt,Au)表面上的吸附行为进行了探讨.通过对噻吩在不同底物金属上的吸附能、吸附构型、Mulliken电荷布居、差分电荷密度以及态密度的分析发现,噻吩在Pd(111)面上的吸附能最大,Pt(111)面次之,Au(111)面最小.吸附后,噻吩在Au(111)面上的构型几乎保持不变,最终通过S端倾斜吸附于top位;噻吩在Pd(111)及Pt(111)面上发生了折叠与变形,环中氢原子向上翘起,最终通过环平面平行吸附于hollow位.此外,噻吩环吸附后芳香性遭到了破坏,环中碳原子发生sp3杂化,同时电子逐渐由噻吩向M(111)面发生转移,M(111)面上的部分电子也反馈给了噻吩环中的空轨道,这种协同作用最终导致了噻吩分子稳定吸附于M(111)面.     

Theoretical Studies on Aromaticity of Spiro Metallaaromatics of (C10H10M)2-(M=Ni,Pd, Pt)

Aiming to identify the spiro metallaaromatic systems with potential application value, (C₁₀H₁₀M)^2?(M=Ni, Pd, Pt) derivatives were theoretically investigated. (C₁₀H₁₀M)^2?-Iso1, which has two 6-membered rings(6MRs) connected by the M spiro atom, is a 14π-aromatic as a whole plane. (C₁₀H₁₀M)^2?-Iso2 has one 6π-aromatic 5MR and one 10π-aromatic 7MR connected by the spiro atom. The free (C₁₀H₁₀M)^2? dianions could not exist due to their rather high frontier orbital energies, while the neutral (C₁₀H₁₀M)Li₂ compounds are extremely stable against dissociation. Since (C₁₀H₁₀M)Li₂ coumponds are not fully coordinated, they trend to form (C₁₀H₁₀M)Li₄²⁺ dications, or even[(C₁₀H₁₀M)Li₂]_n polymers. Arguably, (C₁₀H₁₀M)^2? planes are not the only examples for spiro metallaaromaticity, their derivatives are also potential material building blocks.     

Kinetics and Mechanism of the Thermal Decomposition of M(NO3)2·nH2O (M=Cu,Co, Ni)

This paper presents the results of simultaneous DTA-TG-DTG and DSC studies on the thermal decomposition of Cu(NO3)2·3H2O, Co(NO3)2·6H2O and Ni(NO3)2·6H2O in an air atmosphere. The mechanism and enthalpies of the investigated processes were determined, as well as the kinetic parameters of the processes run under non-isothermal conditions by means of Kissinger's method. The dependence of the activation energy on the ionic radius of the cations building up the crystal lattices of the investigated compounds was also studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

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…     

Proton transfer reactions from N-H acid [5,10,15,20-tetrakis(pentafluorophenyl)-21-H, 23-H-porphyrin] to strong bases in acetonitrile

Deprotonation of 5,10,15,20-tetrakis(pentafluorophenyl)-21-H, 23-H-porphyrin (PhF₅PorH₂) by various bases has been studied by ¹H NMR and kinetic methods. The kinetic parameters in acetonitrile were defined for proton transfer reactions yielding [NH]⁺ protonated bases and [NHN]⁻ anions with intramolecular hydrogen-bonded chains.     

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.     

Powder X-ray diffraction study of the double complexes [M(NH3)5Cl][M"Cl4] as precursors of metal powders (M = Ir,Rh, Co; M" = Pt,Pd)

According to the results of powder X-ray diffraction study of the complex salts of composition [M(NH₃)₅Cl][M"Cl₄] (M = Ir, Rh, or Co and M" = Pt or Pd), the anhydrous salts crystallize in the orthorhombic system (space group Pnma) and are isostructural to the [Ir(NH₃)₅Cl][PtCl₄] complex studied previously. The unit cell parameters of the resulting salts were refined. The metal powders, which were obtained by thermal decomposition of these salts under an atmosphere of hydrogen, were studied by powder X-ray analysis.     

Dissociation characteristics of [M + X]+ ions (X = H,Li, Na,K) from linear and cyclic polyglycols

The unimolecular reactions of protonated and metalated polyglycols with kiloelectronvolt translational energies have been studied by collisionally activated dissociation and neutralization-reionization mass spectrometry. The former method provides information on the ionic dissociation products, whereas the latter allows for the identification of the complementary neutral losses. Protonated linear polyglycols mainly undergo charge-initiated decompositions that lead to eliminations of smaller oligomers. On the other hand, protonated crown ethers (“cyclic” polyglycols) favor charge-induced reactions that proceed by cleavages of two ethylene oxide units in the form of 1,4-dioxane. Replacement of one O by NH in the crown ether dramatically changes its unimolecular chemistry; now, charge-remote 1,4-eliminations from ring-opened isomers are preferred. Charge-remote reactions are also the major decomposition channels of all metalated precursors studied. The linear polyglycols decompose primarily by 1,4-H₂ eliminations and to a lesser extent by homolytic cleavages near chain ends. The reverse is true for metalated crown ethers, which preferentially produce distonic radical cations by the loss of saturated radicals; these reactions are proposed to involve prior rearrangement to open-chain isomers. The nature of the metal ion (Li⁺, Na⁺, or K⁺) does not greatly affect the unimolecular chemistry of the cationized polyglycol. In general, metalated precursors form many abundant fragment ions over the entire mass range; hence, collisional activation of such ions at high kinetic energy should be particularly useful for structure elucidations.