酒石酸钛(IV)配合物的合成和热性质研究

通过四氯化钛与酒石酸反应，制得了新的固态配合物Ｔｉ２Ｏ２（ＯＨ）２Ｃ４Ｈ４Ｏ６·３Ｈ２Ｏ。用元素分析、Ｘ－射线粉末衍射，ＩＲ和ＴＧ分析确定了产物的组成。ＴＧ和ＤＳＣ研究了它在空气氛围下的热分解特性，计算机求解热分解反应各阶段的活化能Ｅａ，反应级数ｎ、焓变面△ｒＨ和熵变面△ｒＳ。在５５０℃灼烧１小时，可得锐钛型ＴｉＯ２。     

Effect of pH on the Chemistry of the Barium Titanium Citrate Gel and Its Thermal Decomposition Behavior

In this investigation, X-ray diffractometry and ¹³C NMR spectroscopy were used to characterize the effect of pH on the formation of gel and its thermal decomposition by the Pechini process. It was found that the major effect of pH was to destroy the esterification between citric acid (CA) and ethylene glycol, which in turn could influence Ba species and the formation of a mixed-metal CA complex. It was also found that barium carbonate was derived from the Ba species and was not related to the instability of Ba₂Ti₂O₅CO₃, but Ba₂Ti₂O₅CO₃ was formed by the thermal decomposition of a mixed-metal CA complex. Moreover, BaTiO₃ formed via two routes, the reaction of BaCO₃ with Ti species and thermal decomposition of Ba₂Ti₂O₅CO₃.     

Thermal Decomposition of Potassium Titanium Hexacyanoferrate（Ⅱ） Loaded with Cesium in a Fixed Bed Calciner

The thermal decomposition of potassium titanium hexacyanoferrate（ Ⅱ ） （KTiFC） loaded with cesium （referred to as Used Exchanger,or UE） was-studied at different flow rate of air in a fixed bed calciner. The calcina t ign processconsisted of four stages：ambient temperature- 180℃ （stageⅠ ）, 180-250℃（stage Ⅱ）, 250-400℃ （stage Ⅲ）, and constant 400℃ （stage Ⅳ）.The most intense reaction occurred in stage .Ⅱ. The rate of thermal decomposition was controlled, depending on the O2 flux, by O2 or CN concentration in ditterent stages. Results from differential thermal analysis （DTA） showed that the calcination reaction of the anhydrous UE was exothermic, with an approximate heat output of 4.6kJ·g^-1, which was so large to cause the possible agglomeration of calcined residues. The agglomeration could be avoided by enhancing heat transfer and controlling the O2 flux. It was found that there was no cyanides in the calcined residues and no CN-bearing gases such as HCN and （CN）2 in the off-gas. It seemed that the catalytic oxidation furnace behind the fixed bed calciner could be cancelled.     

基于 Kissinger 方法的3，4-双（4-硝基呋咱-3-基）氧化呋咱的热分解反应动力学参数和热稳定性研究

采用差示扫描量热法研究了 DNTF和TNT在不同升温速率下的热分解特性;利用Kissinger方法计算和对比分析了DNTF和TNT的热分解反应动力学参数、热爆炸临界温度和热力学参数。结果表明,DNTF的热分解过程不同于TNT ,DNTF的热分解经历了两个阶段,其中第1阶段为主要部分。DNTF的活化能为168．85kJ／mol ,比TNT高约58 kJ／mol ,表明DNTF在低温下有良好的热稳定性。然而,除自由活化能外,DNTF的其他热力学参数均比TNT高。DNTF的热分解峰温和热爆炸临界温度都比 TNT小。因此,与TNT相比,DNTF的热稳定性差。     

新型高能聚合物GAP的热分解和燃烧

简要回顾了GAP的研究历程及应用情况，介绍了有关GAP的特点及研究现状，着重阐述了GAP热分解及燃烧过程的特点，给出了目前比较先进的实验方法及手段，如色谱—质谱联用、热解质谱、分子束质谱、红外激光、紫外激光、CO2激光诱导热解等，可供进一步研究GAP参考。     

非等温热重法研究聚苯醚热分解动力学

采用非等温热重法对聚苯醚的热分解动力学进行研究,计算了反应活化能,采用积分法结合36种动力学函数来判断聚苯醚热分解的机理函数,得到了聚苯醚热动力学参数即反应的动力学函数,平均活化能（E_a）为211.64kJ/mol,指前因子（A）的平均值为6.24×10⁷s^-1,也获得了对应的热分解动力学方程。     

Adsorption Characterization for Multi‐Component Organic Matters by Titanium Oxide (TiO2) in Wastewater

Abstract

In this study, an experimental and analytical study on adsorption and adsorption kinetics of organic matters in titanium oxide (TiO₂, Degussa P25) with synthetic wastewater was investigated. In order to understand the removal of different organic sizes in detail molecular weight (MW) distribution of organics matters was examined in terms of number and weight‐average MW. The large MW (33950 dalton) of synthetic organic matters (SOMs) was significantly removed by TiO₂ adsorption and the slight decrease of the small MW (970 dalton) occurred with time. A characterization method was applied to evaluate the composition of SOMs in terms of adsorbability by adsorption of TiO₂. Several adsorption equilibrium and batch kinetics experiments were conducted with different initial concentrations of SOMs and different amounts of adsorbent. A binomial distribution(s) of SOM fraction with the Freundlich coefficient (k) was obtained. The synthetic wastewater was explained by a finite number of pseudospecies (N) identified with a Freundlich isotherm constant (k) value. These parameters were determined by the characterization procedure, together with ideal adsorbed solution theory (IAST) with the pseudospecies number method. Prediction of adsorption isotherm and kinetics derived from a binomial concentration distribution of the characterization procedure were in good agreement with experimental data conducted.     

新型硬质聚氨酯泡沫的热分解行为及动力学

利用热重分析法比较研究了新型硬质聚氨酯泡沫[超支化聚氨酯多元醇型(HBPU型)]和硬质聚氨酯泡沫(RPUF)在氮气中的热分解行为,探讨了HBPU型RPUF在不同升温速率下的热分解动力学,运用Kissinger最大失重率法和Flynn-Wall-Ozawa等失重百分率法计算获得了其热分解过程的活化能。研究结果表明,HBPU型RPUF的初始分解温度(T5%)为205℃,半寿温度(T50%)为361℃,略低于传统的RPUF。Kissinger法得到的HBPU型RPUF的热分解表观活化能为159.8 kJ/mol;Flynn-Wall-Ozawa法得到的热分解过程分为三个阶段:第一阶段的平均活化能为82.8 kJ/mol,第二阶段的平均活化能为140.7 kJ/mol,第三阶段的平均活化能为111.3 kJ/mol,HBPU型RPUF具有较好的热稳定性。     

Effective Photocatalytic Reduction of Nitrate to Ammonia in an Aqueous Suspension of Metal-Loaded Titanium(IV) Oxide Particles in the Presence of Oxalic Acid

Photocatalytic reduction of nitrate ion (NO₃ ^–) in an aqueous suspension of metal-loaded titanium(IV) oxide (TiO₂) was examined in the presence of oxalic acid (OA) as a hole scavenger. Conversion of NO₃ ^– into ammonia (NH₃) competed with hydrogen liberation, and the NH₃ production selectivity increased with the order of loaded metal, (Pt, Pd, Co) < (Ni, Au) < (Ag, Cu), which was attributable to the efficiency of reduction of protons by photogenerated electrons at the loaded metal, i.e., hydrogen overvoltage of the loaded metal. TiO₂ powder loaded with Cu showed higher NH₃ yield and selectivity as well as higher efficiency of OA consumption. TiO₂ with in situ deposited Cu gave results comparable to those of a Cu pre-loaded photocatalyst.     

Thermal Decomposition and Combustion of Ammonium Dinitramide (Review)

A comprehensive review of thermal decomposition and combustion of ammonium dinitramide (ADN) has been conducted. The basic thermal properties, chemical pathways, and reaction products in both the condensed and gas phases are analyzed over a broad range of ambient conditions. Detailed combustion-wave structures and burning-rate characteristics are discussed. Prominent features of ADN combustion are identified and compared with other types of energetic materials. In particular, the influence of various condensed- and gas-phase processes in dictating the pressure and temperature sensitivities of the burning rate is examined. In the condensed phase, decomposition proceeds through the mechanisms ADN → NH₄NO₃ + N₂O and ADN → NH₃ + HNO₃ + N₂O, the former mechanism being the basic one. In the gas phase, the mechanisms ADN → NH₃ + HDN and ADN → NH₃ + HNO₃ + N₂O are prevalent. The gas-phase combustion-wave structure in the range of 5–20 atm consists of a near-surface primary flame followed by a dark-zone temperature plateau at 600–1000°C and a secondary flame followed by another dark-zone temperature plateau at 1000–1400°C. At higher pressures (60 atm and above), a final flame is observed at about 1800°C without the existence of any dark-zone temperature plateau. ADN combustion is stable in the range of 5–20 atm and the pressure sensitivity of the burning rate has the form r _b = 20.72p ^0.604 [mm/sec] (p = 0.5–2.0 MPa). The burning characteristics are controlled by exothermic decomposition in the condensed phase. Above 100 atm, the burning rate is well correlated with pressure as r _b = 8.50p ^0.608 [mm/sec] (p = 10–36 MPa). Combustion is stable, and intensive heat feedback from the gas phase dictates the burning rate. The pressure dependence of the burning rate, however, becomes irregular in the range of 20–100 atm. This phenomenon may be attributed to the competing influence of the condensed-phase and gas-phase exothermic reactions in determining the propellant surface conditions and the associated burning rate. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 6, pp. 54–79, November–December, 2005.     

TATB的热分解及其在[Emim]Ac/DMSO溶剂中的热爆炸特性

用DSC-TG研究了TATB的热分解过程。根据升温速率分别为5、10、15、20K/min的DSC和TG-DTG曲线计算了分解反应的活化能(E)、指前因子(A)和120℃时的速率常数(k120),并计算了升温速率为5K/min时,TATB分解峰值温度时的分解反应活化焓、活化熵和活化自由能,用小容量测试法研究了TATB在1-乙基-3-甲基咪唑醋酸盐/二甲基亚砜([Emim]Ac/DMSO)溶剂中的热爆炸特性。结果表明,采用Kissinger法和Ozawa法计算得到TATB分解反应的活化能分别为212.1和212.0kJ/mol,采用Rogers公式和Arrhenius公式计算得到A和k120值分别为5.87×1016s-1和3.87×10-12s-1;升温速率为5K/min条件下,TATB分解峰值温度时的分解反应活化焓、活化熵和活化自由能分别为206kJ/mol、61.42J/(K·mol)和167.39kJ/mol,TATB粉末的临界爆炸温度为336.6℃;TATB在[Emim]Ac/DMSO溶剂中不爆炸。     

Synthesis of NaTi2(PO4)3 by the Inorganic–Organic Steric Entrapment Method and Its Thermal Expansion Behavior

Crystalline pure NaTi₂(PO₄)₃ (NTP) powder was synthesized at 700°C using a simple and low energy, hybrid inorganic–organic, steric entrapment method. Sodium nitrite (NaNO₂) and ammonium phosphate dibasic ((NH₄)₂HPO₄) dissolved in water, whereas titanium (IV) isopropoxide (Ti[OCH(CH₃)₂]₄) hydrolyzed in water. Ethylene glycol (HOCH₂CH₂OH) was used as a polymeric entrapper and hydrolysis of the Ti source was hindered by its dissolution in isopropyl alcohol. The resulting NTP powder was characterized by thermogravimetric analysis/differential thermal analysis, X‐ray diffractometry, scanning electron microscopy, specific surface area by Brunauer–Emmett–Teller nitrogen absorption, and particle size analysis. Furthermore, C, H, N were measured by the classical Pregl‐Dumas method. The thermal expansion behavior in all {hkl} pole directions was also determined by in situ high‐temperature X‐ray diffraction using synchrotron radiation and was found to be in agreement with other published studies.     

Investigation of Structural,Morphological and Magnetic Properties of MFe2O4 (M = Co,Ni, Zn,Cu, Mn) Obtained by Thermal Decomposition

The structural, morphological and magnetic properties of MFe₂O₄ (M = Co, Ni, Zn, Cu, Mn) type ferrites produced by thermal decomposition at 700 and 1000 °C were studied. The thermal analysis revealed that the ferrites are formed at up to 350 °C. After heat treatment at 1000 °C, single-phase ferrite nanoparticles were attained, while after heat treatment at 700 °C, the CoFe₂O₄ was accompanied by Co₃O₄ and the MnFe₂O₄ by α-Fe₂O₃. The particle size of the spherical shape in the nanoscale region was confirmed by transmission electron microscopy. The specific surface area below 0.5 m²/g suggested a non–porous structure with particle agglomeration that limits nitrogen absorption. By heat treatment at 1000 °C, superparamagnetic CoFe₂O₄ nanoparticles and paramagnetic NiFe₂O₄, MnFe₂O₄, CuFe₂O₄ and ZnFe₂O₄ nanoparticles were obtained.     

Thermal Decomposition of Alkoxides in an Inert Organic Solvent: Novel Method for the Synthesis of Homogeneous Mullite Precursor

Thermal decomposition of a mixture of aluminum iso-propoxide and tetraethoxysilane (Al/Si = 3) in toluene at 300°C was examined. The reaction completely proceeded and yielded an amorphous product. The DTA profile of the product showed a sharp peak at ∼1000°C which was associated with crystallization of mullite and a small amount of the spinel phase. The mullite prepared by calcination of the product at 1300°C was composed of micro-crystals having an average diameter of 30 nm and had a large surface area of 41 m²g.     

二甲基苯基硅氧基封端聚(二甲基-甲基苯基)硅氧烷共聚物的热分解性能及动力学研究

以1,1,3,3-四甲基二苯基二硅氧烷为封端剂,八甲基环四硅氧烷与甲基苯基环硅氧烷混合物为共聚单体,在阴离子催化剂作用下合成了二甲基苯基硅氧基封端的聚(二甲基-甲基苯基)硅氧烷共聚物。采用非等温TG技术,在惰性气氛和5.0、10.0、15.0和40.0 K min 1线性升温速率条件下,考察了共聚物非等温热降解机理及反应动力学,采用Friedman-Reich-Levi、Flynn-Wall-Ozawa和Kissinger等方法对非等温动力学数据进行分析,所得平均表观活化能分别为113.64、115.69和145.80 kJ mol 1。采用等转化率法确定出共聚物热分解反应符合Avrami-Erofeev方程,反应机理为随机成核和随后生长。采用Crane和Doyle方法研究了不同升温速率对反应级数、活化能和指前因子的影响,结果表明降解反应为一级反应,反应活化能介于152.46~183.13 kJ mol 1之间,指前因子介于4.25×109~4.02×109s 1。同时采用等温TG技术得到失重5%和10%条件下的寿命方程,对共聚物的寿命进行了预测。     

新型稀土配合物Tb(bza)3(dpe)(H2O)3的表征及热分解动力学性质

合成了新型稀土固态配合物Tb（bza）3（dpe）（H2O）3[（Hbza=Benzoic acid,dpe=1,2-Di-（4-pyridyl）-ethylen]。通过元素分析和化学分析确定了配合物的组成,采用红外光谱等技术对配合物进行了表征,研究了配合物的荧光性能,用TG-DTG法研究了配合物的热分解行为,用非模型等转化率法研究了配合物热分解脱水过程的动力学,获得其表观活化能、指前因子数值范围、最概然机理函数和模型函数。     

Nanocrystalline Brookite-Type Titanium(IV) Oxide Photocatalysts Prepared by a Solvothermal Method: Correlation Between Their Physical Properties and Photocatalytic Activities

Mesoporous MSU-X alumina molecular sieves were synthesized through the neutral N⁰I⁰ assembly pathway using aluminum sec-butoxide as the precursor and a triblock poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) as the structure-directing agent. Their surface acidity and basicity as well as textural properties were characterized by NH₃-TPD, CO₂-TPD, IR spectroscopy and N₂ adsorption methods. The materials are abundant in surface weak acid sites and weak-medium basic sites. They are more active than the commercial -Al₂O₃ catalyst for the CS₂ hydrolysis reaction, and the temperature of 90 conversion of CS₂ on the mesoporous alumina is 130K lower than that of -Al₂O₃.     

ADNBF的热分解机理及临界热爆炸温度的研究

采用DSC及FT－IR技术，对含能材料7－氨基－4，6－二硝基苯氧化呋咱（ADNBF）的热分解行为进行了研究，同时通过分析非等温DSC曲线，计算得到ADNBF的临界热爆炸温度。     

Thermal Behavior and Decomposition Kinetics of Bis(2,2,2‐trinitroethyl)‐oxalate as a High Energy Dense Oxidizer and its Mixture with Nitrocellulose

A new propellant formulation (NC‐BTNEOx) based on bis(2,2,2‐trinitroethyl)oxalate (BTNEOx) as a high energy dense oxidizer (HEDO) mixed with nitrocellulose (NC) matrix was prepared and studied. BTNEOx was prepared and characterized by nuclear magnetic resonance (NMR) and X‐ray diffraction (XRD). Photos of the prepared formulation obtained by scanning electron microscope (SEM) clarified a good mixing of the nitrocellulose (NC) matrix with BTNEOx. A smokeless burning was observed and recorded for the prepared NC‐BTNEOx by a high speed camera. The thermal behavior and decomposition kinetics of the NC matrix, BTNEOx and their mixture have been investigated nonisothermally by using thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC). Isoconversional (model‐free) methods; Kissinger, Ozawa and Flynn−Wall (OFW) and Kissinger−Akahira−Sunose (KAS), were used to determine the kinetic parameters of the studied samples. The results proved that BTNEOx has melting temperature at 104.1 °C and maximum peak temperature at 200.6 °C, also it has effective activation energy in the range of 107–110 kJ/mol. The prepared NC‐BTNEOx has no endothermic peak and has exothermic peak at 201.7 °C which means that a composite might be formed due to the mixing of BTNEOx with NC. The prepared NC‐BTNEOx has effective activation energy in the range of 172–180 kJ/mol. BTNEOx required more study to proof the possibility of replacing the nitroglycerine in a smokeless double base propellant.