Non-isothermal decomposition kinetics and lifetime of Tb2(0-MBA)6(PHEN)2

The thermal decomposition of Tb2(O-MBA)6(PHEN)2 (O-MBA: o-methylbenzoate; PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition by thermogravimetry-derivative thermogravimetry (TG-DTG) techniques. Kinetic parameters were obtained from analysis of TG-DTG curves by the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The most probable mechanism function was suggested by comparing the kinetic parameters. The kinetic equation for the first stage can be expressed as dcddt = Aexp(-E/RT) 3(1 - α)2/3 The lifetime equation at mass loss of 10% was deduced as lnr= -28.7429 + 19797.795/Tby isothermal thermogravimetric analysis.     

Thermal decomposition kinetics and lifetime of the complex of Tb2（BA）6（PHEN）2

The thermal behavior of Tb2(BA)6(PHEN)2 (BA: benzoate, and PHEN: 1,10-phenanthroline) in a static air atmospbere was investigated by TG-DTG, SEM and IR techniques. By the kinetic method of processing thermal analysis data put forward by Malek et al., it is defined that the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energy E for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS^≠ is -84.72 J/mol, the enthalpy of activation ΔH^≠ is 94.26 kJ/mol, the free energy of activation ΔG^≠ is 144.77 kJ/mol and the pre-exponential factor lnA is 20.93.The lifetime equation at mass-loss of 10% was deduced as lnτ = -29.0312 19760.83/T by isothermal thermogravimetric analysis.     

Non-isothermal kinetics of the first-stage decomposition reaction of the complex of samarium p-methoxybenzoate with 1,10-phenanthroline

The complex of [Sm(p-MOBA)3phen]2 (p-MOBA, p-methoxybenzoate; phen, 1,10-phenanthroline) was pre- pared and characterized by elemental analysis, IR, and UV spectroscopy. The thermal decomposition of the [Sm(p-MOBA)3phen]2 complex and its kinetics were studied under a static air atmosphere by TG-DTG methods. The in- termediate and residue for each decomposition stage were identified from the TG curve. The kinetic parameters and mecha- nisms of the first decomposition stage were obtained from the analysis of the TG-DTG curves by a new method of process- ing the data of thermal analysis kinetics. The lifetime equation at a mass loss of 10% was deduced as lnτ = – 30.6795 21034.56/T by isothermal thermogravimetric analysis.     

Thermal decomposition mechanism and non-isothermal kinetics of the polyoxometalate of ciprofloxacin with 12-tungstoboric acid

The polyoxometalate complex (CPFX·HCl)4H5BW12O40·12H2O was prepared in aqueous solution for the first time, and characterized by elemental analysis, IR spectrum, and TG-DTG. The TG-DTG curves showed that its thermal decomposition was a four-step process     

高岭石脱水反应的非等温热重法研究

在系统分析非等温固相反应特点的基础上,建立了非等温脱水反应速率方程.采用非等温热重法、通过计算机辅助计算,对高岭石脱水反应动力学规律进行了研究.结果表明:由于高岭石晶体结构中内、外羟基脱除的顺序不同,其脱水反应机制在反应分数(α)为0.7左右时发生改变.在反应前期(0＜α＜0.7)时,脱水反应遵循二维扩散控制规律,脱水反应表观活化能为159.682 kJ/mol、表观频率因子为1.007×10 10/min.     

Non-isothermal microwave leaching kinetics and absorption characteristics of primary titanium-rich materials

The non-isothermal leaching kinetics of primary titanium-rich material by microwave heating was investigated, and the temperature-pressure curves of leaching system and microwave absorption characteristics of mixture solutions before and after leaching were measured. The research of non-isothermal kinetics was evaluated by the leaching rate of Fe and the total apparent velocity equation of the non-isothermal kinetics of leaching for primary titanium-rich material by microwave heating was obtained. It is shown from the temperature-pressure curves that the high temperature and high pressure of closed leaching system are favorable to the enhancement of the leaching rate of Fe. Microwave absorption characteristics of mixture solutions before and after leaching show that there are abrupt changes of microwave absorption characteristics for 15% HCl solution and the mixture solution after leaching by 20% HCl.     

Crystal structure and properties of terbium o-methylbenzoate complex with 1,10-phenanthroline [Tb（o-CH3C6H4COO）3（C12H8N2）]2

A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen (where o-MBA =o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solution and its crystal structure was deter-mined by X-ray diffraction. The crystal of the complex Tb(o-MBA)_3phen belongs to triclinic crystal system and P 1 (#2)space group. The crystal data are as follows: a=1.4371(4)nm, b=1.7387(2)nm, c=1.3109(2)nm, α=96.37(1)°,β=107.21(2)°, γ=82.78(2)°, V=3.094(1)nm~3, Z=2, M_r=1489.12, D_c=1.598g·cm, μ=2.330mm~(-1) and F(000)=1488.00.The final R and R_w are 0.038 and 0.047 for 8668Π>2σ(Ⅰ)] unique reflections, respectively. In the complex each Tb~(3 ) ion iseight-coordinated by one 1,10-phenanthroline molecule, one bidentate carboxytate group and four bridging carboxylategroups. The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and the bridging biden-tate. Excitation and luminescence data observed at room temperature show that the title complex emits     

Zr_(47)Cu_(44)Al_9大块非晶合金的变温晶化行为

利用示差扫描量热仪(DSC)研究了Zr_(47) Cu_(44)Al_9大块非晶合金在连续升温过程中的的变温晶化行为.利用Kissinger方法计算其特征温度表观激活能,利用Doyle方法计算其局域激活能.结果表明,Zr_(47) Cu_(44)Al_9大块非晶合金具有良好的热稳定性.利用Kissinger方法计算得到的其玻璃转变激活能E_g为390.2kJ/mol、晶化激活能E_x为325.1kJ/mol、晶化峰值的激活能E_p为299.5kJ/mol.随着加热速率的提高,各特征温度值向高温端移动,其晶化峰值温度所对应的晶化体积分数减小.局域激活能随着非晶晶化体积分数的增加而逐渐减小.     

Magnetic properties and crystallization kinetics of Zn_(0.5) Ni_(0.5) Fe_2O_4

Precursor of nanocrystalline Zn0.5Ni0.5Fe2O4 was obtained by grinding mixture of ZnSO4·7H2O,NiSO4·6H2O,FeSO4·7H2O,and Na2CO3·10H2O under the condition of surfactant polyethylene glycol(PEG)-400 being present at room temperature,washing the mixture with water to remove soluble inorganic salts and drying it at 373 K.The spinel Zn0.5Ni0.5Fe2O4 was obtained via calcining precursor above 773 K.The precursor and its calcined products were characterized by differential scanning calorimetry(DSC) ,Fourier transform ...     

Synthesis and thermal decomposition kinetics of LiNiO2

A layered LiNiO2 with high crystallinity was synthesized by sintering the finely prepared mixture of lithium hydroxide and nickel hydroxide in the oxygen atmosphere. The electro-chemical properties of LiNiO2 show that it has a reversible capacity of more than 168mA*h*g-1. It was found that with increasing temperature, LiNiO2 decomposed in air followed with three reaction stages, the apparent activation energies were 747.18±1.0kJ*mol-1, 932.46±1.0kJ*mol-1 and 1126.97±1.0kJ*mol-1 respectively, and the kinetic equations of the three reaction stages were obtained.     

Synthesis and fluorescent properties of europium–polymer complexes containing 1,10-phenanthroline

In this paper, 5-acrylamido-1,10-phenanthroline (AP) was synthesized, then the luminescence material containing Eu–polymer complexes were obtained by two methods. The polymer structure and properties were characterized by FT-IR, UV, fluorescence spectra, DSC, GPC, ICP and XRD. Compared with the two methods the rare earth ions-containing polymers, we obtained copolymer B by the second one that had high and stable fluorescence intensity with the Eu content 0.31%. Comparing the two results via different methods, we have set down the useful basement for the study of the luminescence material containing Eu–polymer complexes.     

Theoretical analysis and experimental verification of thermal decomposition mechanism of CuSe

Experiments on the thermal decomposition of CuSe were carried out by using a thermogravimetric analyzer (TGA) at different heating rates. The kinetic parameters and mechanisms were discussed based on model-free and model-based analyses. The decomposition rate and decomposition behavior of CuSe were investigated by using a vacuum thermogravimetric furnace. The results showed that the R3 model was identified as the most probable mechanism function under the present experimental conditions. The average values of activation energy and the pre-exponential factor were 12.344 J/mol and 0.152 s^-1, respectively. The actual decomposition rate of CuSe was found to be 0.0030 g/(cm²·min).     

Al1.49Si1.45Zr0.26(TiCaMg)0.37O6.43非晶的非等温晶化动力学

采用非等温差示扫描量热分析方法,结合X射线衍射和红外光谱,研究了Al1.49Si1.45Zr0.26(TiCaMg)0.37O6.43非晶晶化动力学.结果表明:非晶在1223～1273 K附近发生了四方氧化锆的析出反应,析晶活化能为518～538 kJ/mol;在1423～1473 K附近发生了莫来石和方石英的析出反应,其析晶活化能为522～545 kJ/mol,且氧化锆的存在能有效地降低莫来石的析晶活化能.     

Kinetics of Therm al Decom position of[ Eu_2( p- M O B A)_6(phen)_2]( H_2 O)_2 in Static Air Atmospher

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40Cr钢等温转变曲线与非等温冷却过程数值分析

建立连续冷却过程多相转变模型,并实现了对冷却过程中各相转变量的数值预测。用传统叠加模型和Cahn微分模型分别对40Cr钢连续冷却过程中组织分布进行了模拟计算,结果表明,考虑动力学参数n随温度变化的相变动力学微分方程计算结果与实际结果更为接近。为分析晶粒尺寸对相变过程的影响,结合不同奥氏体化温度下的等温膨胀实验,讨论了考虑晶粒尺寸时的相变动力学模型的应用范围,不同晶粒度下的相变参数n相同时,模型才能准确反应实际相变过程。     

Thermal stability and luminescence properties of 1,10-phenanthroline-tris （m-methylbenzoate） europium （or terbium） complexes in SiO2 gel

Silica gel luminophors containing 1, l O-phenanthroline-tris(m-methylbenzoate) europium (or terbium) complexes were prepared by sol-gel method. The thermal decomposition, excitation and emission spectra for the gel phosphors were measured and compared with that of solid complex powders. The thermal stability of the complexes was enhanced in SiO2 host matrix and the luminescence intensity remained unchanged.     

PEO及其与LiClO4复合体系的非等温结晶动力学

用示差扫描量热法(DSC)研究了聚氧化乙烯(PEO)及其与高氯酸锂(LiClO4)复合体系的非等温结晶过程。依次用Jeziorny方法、一种结合Avrami和Ozawa方程的方法分析了以上体系中PEO的非等温结晶过程,得到了PEO在不同体系中非等温结晶时的动力学参数。动力学参数表明LiClO4晶粒缩短了PEO的结晶时间,使复合体系中PEO的结晶速率大于PEO体系的,但PEO体系形成更完善晶体;为使二者达到相同的相对结晶度,PEO体系需要更大的冷却速率。结果表明,LiClO4晶粒能够有效地将PEO的结晶相转变成非晶相,即LiClO4可有效地抑制PEO的结晶过程。     

Effect of As(III) on kinetics of Fe2+ bio-oxidation

Fe²⁺ bio-oxidation influenced by toxic metal ions released from the dissolution of arsenic-bearing gold ores was investigated. Fe²⁺ bio-oxidation by moderately thermophilic microorganisms was studied under different initial concentrations of Fe²⁺ and As(III), and Monod equation was used to fit the Fe²⁺ bio-oxidation under different conditions. Results showed that the Fe²⁺ bio-oxidation rate increased as the initial Fe²⁺ concentration increased until it reached 12 g/L. As(III) severely inhibited Fe²⁺ bio-oxidation. When the As(III) concentration was 8 g/L, 9 g/L Fe²⁺ was more than 200 h. The Monod equation fitted the Fe²⁺ bio-oxidation well. In the absence of As(III), the maximum specific growth rate of the culture and the substrate affinity constant were 0.142 h^-1 and 0.053 g/L, respectively. As(III) inhibited Fe²⁺ bio-oxidation via competitive inhibition, and the inhibition constant was 0.0035 g/L.     

三氯三氨合铑的热解机理及非等温动力学研究

用TG-DTA、IR及X-射线衍射方法研究fac-和mer-[Rh(NH_3)Cl_3]的热解机理。在氮气气氛中加热至315～375℃二者均出现分解并失重约60％,相应的分解活化能分别为596和627kJ/mol。mer-[Rh(NH_3)_3Cl_3]在氢气气氛中以加热速度2℃/min加热时,则热解温度范围更宽,并分三步失重,其相应的活化能分别为336.24,307.42及1380kJ/mol。     

Fe41Co7Cr15Mo14Y2C15B6大块非晶合金的变温晶化动力学研究

采用差热分析法(DTA)研究了具有高玻璃形成能力的Fe41Co7Cr15Mo14Y2C15B6块体非晶合金的变温晶化动力学.由热分析曲线得到玻璃转变温度Tg、晶化起始温度Tx和晶化峰值温度Tp1、Tp2,这些特征温度具有明显的动力学效应.运用Kissinger法和Ozawa法分别计算出不同升温速率下该Fe基块体非晶合金的玻璃转变激活能Eg、晶化激活能Ex与激活能Ep1、Ep2.采用Kissinger方法和Ozawa方法解释了此大块非晶合金具有高的热稳定性的热力学机制.