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158.84kJ·mol-1和109.85s-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=109.85(1-α)e-1.91×104/T.     

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。     

3,4-二硝基吡唑热分解及非等温动力学

采用TG-DSC综合热分析的方法,对3,4-二硝基吡唑(DNP)的热分解和非等温动力学进行了研究。结果表明DNP的热分解分两阶段进行,并且在升温速率达到15K/min时才能明显区分。分别采用Archar微分法和Coats-Redfen积分法计算了DNP第一阶段热分解反应动力学参数:Ea=91.6kJ.mol-1,lnA=42.7s-1。最可能的DNP热分解机理为随机成核和随后生长机理,符合动力学机理函数Avrami-Erofeev方程,n=3。     

α-磷酸锆的制备及热分解非等温动力学研究

采用改进的直接沉淀氟配位法,在常温常压下制备出了α－磷酸锆（α－ＺｒＰ）,ＸＲＤ结果表明它的层间距为０．７６５ｎｍ,结晶度较好,并以热重分析法（ＴＧ）为手段,对α－ＺｒＰ的热分解过程和非等温热分解动力学机理进行了研究。结果显示,在线性升温速率为１０℃／ｍｉｎ时,α－ＺｒＰ在１３１℃开始脱结晶水;脱去结晶水后形成的Ｚｒ（ＨＰＯ４）２在４５３℃进行磷羟基缩合,至７２０℃完全分解为ＺｒＰ２Ｏ７。脱结晶水和分解过程的失重分别为６．２４％和５．６４％,与理论值基本相符。动力学研究确定了Ｚｒ（ＨＰＯ４）２分解反应属于Ａｖｒａｍｉ－Ｅｒｏｆｅｅｖ的成核和核成长为控制步骤的Ａｌ机理,热分解反应表观活化能为１６５．６ｋＪ／ｍｏｌ,频率因子为３．５０×１０７ｓ－１。     

α-磷酸锆的制备及热分解非等温动力学研究

采用改进的直接沉淀氟配位法,在常温常压下制备出了α-磷酸锆(α-ZrP),XRD结果表明它的层间距为0.765 nm,结晶度较好,并以热重分析法(TG)为手段,对α-ZrP的热分解过程和非等温热分解动力学机理进行了研究。结果显示,在线性升温速率为10℃/min时,α-ZrP在131℃开始脱结晶水;脱去结晶水后形成的Zr(HPO₄)₂在453℃进行磷羟基缩合,至720℃完全分解为ZrP₂O₇。脱结晶水和分解过程的失重分别为6.24%和5.64%,与理论值基本相符。动力学研究确定了Zr(HPO₄)₂分解反应属于Avrami-Erofeev的成核和核成长为控制步骤的Al机理,热分解反应表观活化能为165.6 kJ/mol, 频率因子为3.50×10⁷ s^-1。     

Mg(OH)2热分解反应的非等温动力学研究

用非等温动力学方法对氢氧化镁的热分解动力学进行了研究. 分解反应机理符合晶核形成及生长机理A，且随着升温速率的升高，机理由A2转变为A1.5. 根据Kissinger非机理方程计算和数值回归方法验证所得的分解反应活化能结果相互印证，约为148 kJ•mol^-1. 进一步研究发现，水蒸气的存在对氢氧化镁热分解反应具有非常明显的影响，可能是其动力学机理随升温速率升高而改变的主要影响因素.     

一种新的非等温动力学方程

用热分析法研究聚合热降解或固体热分解反应动力学￣［１］，可用微分法和积分法进行数据处理。前者直接从热谱图上读取值，可能引入大的误差，故更多的是采用积分法。而积分动力学方程中有一个不可积项∫ｅｘｐ（—Ｅ／ＲＴ）ｄ＿Ｔ，为了求解，许多作者对该项作了近似处理。本文在以前近似式的基础上，提出了一个新的非等温动力学方程，并对各近似式在不同ｘ（ｘ＝Ｅ／ＲＴ）下与相应的∫ｅｘｎ（－Ｅ／ＲＴ）ｄ＿Ｔ积分值比较，得出各个近似式的误差范围，并以误差σ对ｘ作图。从结果可见，本文提出的方程在使用范围和精度上都有进一步的提高。     

地开石热分解过程及非等温动力学研究

Fourier-transform infrared emission spectroscopy was used to study the dehydroxylation behavior of the thermal decomposition of dickite from Chenxi, Hunan Province, China. Dehydroxylation of dickite was followed by a loss of intensity of the 3620.73, 3695.34 cm-1 OH-stretching bands and 916.06, 1009.33 cm-1 OH bending bands. The thermal decomposition was investigated by thermogravimetric analysis (TGA). A good agreement is found with TG curves of dickite and the mass loss is 13.7% (close to the theoretical value). The non-isothermal kinetics of the thermal decomposition of dickite was studied in TG-DTG curves over the temperature range from 298 K to 1123 K by thermogravimetry and differential thermal analysis in air. Mathematical analysis of TG-DTG data using the integral methods (Coats-Redfern equation, HM equation, MKN equation) and differential method (Achar equation) shows that the thermal decomposition of dickite accords F2 mechanism. The kinetic parameters such as the activation energy (E=131.62 kJ/mol), pre-exponential factor (A=108.30 s-1) and reaction order (n=2.1) are reported. The Ozawa method was used to analyse the activation energy of the same sample at different heating rate and gave 133.07 kJ/mol. The kinetic parameters calculated from different equation are rather close to each other.     

Zn(C9H6O5N2)·2H2O配合物热分解非等温动力学的研究

合成了Ｚｎ（Ｃ９Ｈ６Ｏ５Ｎ２）·２Ｈ２Ｏ,用元素分析、红外光谱、摩尔电导对该配合物进行了表征。并用热重（ＴＧ）对其热分解机理进行了研究,推断出了该配合物第三步热分解的非等温动力学方程为： ｄα／ｄｔ＝ Ａｅ－ Ｅ／ＲＴ（１－ α）。     

非等温TG- DTG法确定2,2'- 联吡啶- 对甲氧基苯甲酸铕(Ⅲ)热分解反应的机理函数和动力学参数

采用TG-DTG和DTA技术研究了2,2'-联吡啶-对甲氧基苯甲酸铕(Ⅲ)在静态空气中的非等温热分解过程及动力学,根据TG曲线确定了热分解过程中的中间产物及最终产物,运用微分法与积分法对非等温动力学数据进行分析,推断出第一步的动力学方程为dα/dt=Aexp(-E/RT)2(1-α)1/2.     

Preparation, Crystal Structure and Thermal Decomposition Character of [Ni(CHZ)3]SO4·3H2O

A new coordination compound [Ni(CHZ)₃]SO₄·3H₂O (CHZ=carbohydrazide) was synthesized and characterized by elemental analysis and fourier transform infrared (FTIR) spectra, and its crystal structure was determined by X-ray single crystal diffraction. The crystal belonged to the triclinic system, space group with a=0.85237(1) nm, b=0.90964(1) nm, c=1.22559(2) nm, β=96.731(2)°, V=0.8849(2) nm³, Z=2, D_c=1.798 g·cm⁻³. In the asymmetric unit, three carbohydrazide (CHZ) bidentate ligands were coordinated with a Ni(II) cation by carbonyl O atoms and terminal N atoms of the hydrazine groups to form three planar chelate rings which were vertical to one another. Ni(II) cations, CHZ ligand molecules, sulfate anions, and lattice water molecules were jointed to a complicated three-dimensional network structure through coordination bonds, electrostatic forces and extensive hydrogen bonds. Natural bond orbital (NBO) atomic charges of CHZ were obtained from the density functional theory (DFT) method at the B3LYP/6-311+G^** level to interpret the reason why the coordination sites in carbohydrazide molecule were the oxygen atom of the carbonyl group and terminal N atoms of the hydrazine group. The thermal decomposition mechanism was tested through differential scanning calorimetry (DSC), thermogravimetric analyses, and Fourier transform infrared spectra. The kinetic parameters of the two exothermic processes of the title compound were studied applying the Kissinger's and Ozawa-Doyle's methods. The results indicated that the title complex possessed high energy and good thermal stability.     

Nonisothermal Kinetics of Dehydration Process of [Sm（m-CIBA）3phen]2·2H2O and [Sm（p-CIBA）3phen]2·2H2O

Compounds [Sm（m-CIBA）3phen]2.2H20 and [Sm（p-CIBA）3phen]2·2H20（m-CIBA=m-chlorobenzoate, pClBA=p-chlorobenzoate, phen=l,10-phenanthroline） were prepared. The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics. The Arrhenius equation for the dehydration process can be expressed as lnk=-38.65-243.90×l0^3/RT for [Sm（m-CIBA）3phen]2·2H2O, and lnk=38.70-172.22×103/RT for [Sm（p-CIBA）3phen]2·2H2O. The values of △H^1, △G^1, and △S^1 of dehydration reaction for the title comnonnds are determined respectively.     

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.     

Thermal decomposition of Cu(NO3)2·3H2O at reduced pressures

Thermolysis of Cu(NO₃)₂·3H₂O is studied by means of XRD analysis in situ and mass spectral analysis of the gas phase at P=1/10 Pa at low heating rate. It is shown that stage I of the dehydration (40-80 °C) results in the consecutive appearance of crystalline Cu(NO₃)₂·2.5H₂O and Cu(NO₃)·H₂O. Anhydrous Cu(NO₃)₂ formed during further dehydration at 80-110 °C is moderately sublimed at 120-150 °C. Dehydration is accompanied by thermohydrolysis, leading to the appearance of Cu₂(OH)₃NO₃ and gaseous H₂O, HNO₃, NO₂, and H₂O. The higher pressure in the system, the larger amount of thermohydrolysis products is observed. The formation of the crystalline intermediate CuO_x(NO₃)_y was observed by diffraction methods. Final product of thermolysis (CuO) is formed at 200-250 °C.     

超细AgO粉末:制备及热分解非等温动力学

采用化学沉淀法,以臭氧为氧化剂制备了超细AgO粉末,并用XRD、XPS、SEM和粒度分析仪对制备的粉末进行了表征,借助热重分析法(TG)和线性升温理论对超细AgO粉末的热分解过程和非等温热分解动力学机理进行了研究。结果表明,制备的AgO属于单斜晶系,形貌为片状,其粒径分布在45～551nm之间,大部分在200nm左右;AgO的热分解分两步,158℃开始分解,放出氧气形成Ag2O,413℃进一步分解形成Ag;其热分解反应服从核生成和核成长为控制步骤的A2机理,热分解表观活化能为90.26kJ·mol-1,反应频率因子为1.64×108s-1。     

Calorimetric study and thermal analysis of [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O and [ErY(Gly)6(H2O)4](ClO4)6·5H2O (Gly: glycin)

Two solid-state coordination compounds of rare earth metals with glycin, [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O and [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O were synthesized. The low-temperature heat capacities of the two coordination compounds were measured with an adiabatic calorimeter over the temperature range from 78 to 376 K. [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 342.90 K, while [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 328.79 K. The molar enthalpy and entropy of fusion for the two coordination compounds were determined to be 18.48 kJ mol⁻¹ and 53.9 J K⁻¹ mol⁻¹ for [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, 1.82 kJ mol⁻¹ and 5.5 J K⁻¹ mol⁻¹ for [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, respectively. Thermal decompositions of the two coordination compounds were studied through the thermogravimetry (TG). Possible mechanisms of the decompositions are discussed.     

[Pb2(TNR)2(CHZ)2(H2O)2]4H2O的结构及热分解机理

The coordination compound of [Pb 2(TNR) 2(CHZ) 2(H 2O) 2]•4H 2O was prepared by using the aqueous solution of carbohydrazide, lead nitrate and sodium styphnate. The molecular structure of [Pb 2(TNR) 2(CHZ) 2(H 2O) 2]•4H 2O(C 7H 13 N 7O 12 Pb, Mr=594.43) was determined by using a single crystal diffraction analysis .The thermal decomposition mechanism of the title compound was studied by TGDTG, DSC and IR techniques. The crystal belongs to monoclinic with space group P2 1/n.The unit cell parameters are as follows: a=0.64700(10)nm, b=1.6074(3)nm, c=1.4883(3)nm,β=97.42(2)°,V=1.5349(5)nm3, Z=2, DC=2.572g•cm -3 ,μ(Mo, Kα)=11.080cm -1 , F(000)=1128. R=0.0422, Rw=0.0735. The binuclear lead coordination compound is bridged by two carbohydrazide molecules. The molecule has a symmetrical center. TNR 2- ,CHZ and H 2O coordinate with the central ions simultaneously.     

The role of anhydrous zinc nitrate in the thermal decomposition of the zinc hydroxy nitrates Zn5(OH)8(NO3)2·2H2O and ZnOHNO3·H2O

The steps associated with the thermal decomposition of Zn₅(OH)₈(NO₃)₂·2H₂O and ZnOHNO₃·H₂O are re-examined. Previous reports have suggested that Zn₅(OH)₈(NO₃)₂·2H₂O decomposes to ZnO via two intermediates, Zn₅(OH)₈(NO₃)₂ and Zn₃(OH)₄(NO₃)₂ whereas ZnOHNO₃·H₂O has been reported to decompose to ZnO via a Zn₃(OH)₄(NO₃)₂ intermediate. In this study, we demonstrate using TG, mass spectral analysis of evolved gases and in situ variable temperature powder X-ray diffraction analysis that, in fact, in the decomposition of Zn₅(OH)₈(NO₃)₂·2H₂O an anhydrous zinc nitrate intermediate is also involved. We, additionally, show that the decomposition of ZnOHNO₃·H₂O to ZnO also involves the formation of an anhydrous zinc nitrate intermediate. The anhydrous zinc nitrate formed in both cases is poorly crystallised and this observation may explain why this phase could not be observed by PXRD analysis in the previous studies.     

双核Cu(I)配合物的热分解非等温动力学

Thermal decomposition process of four benzimidazolyl-containing dicopper(Ⅰ) complexes: [Cu2(OCTB)](ClO4)2•1.5H2O(1), [Cu2 (NMOCTB)](ClO4)2•H2O(2), [Cu2(NBUOCTB)](ClO4)2(3), [Cu2(NBOCTB)](ClO4)2•H2O(4) and their kinetics were studied under the non-isothermal conditions by TG-DTG techniques. The non-isothermal kinetic data were analyzed by means of Achar and Coats-Redfern method respectively. The kinetic equation for the second step of the decomposition of complex (1) can be expressed as: dα/dt=A•exp(-E/RT) •(1-α), the mechanism of this reaction corresponds to "Coring and Growth" with n=1; while for the first step of complex (3) decomposition, dα/dt=A•exp(-E/RT)• (1-α)2, which corresponds to the mechanism of "the second-order chemical reaction".