MC2O4(M=Mn、Fe、Co、Ni、Cu、Zn)的热力学及其热分析动力学

用DSC、TGA技术分别在N₂气氛和O₂气氛下对MC₂O₄(M=Mn、Fe、Co、Ni、Cu、Zn)的脱水和分解过程作了热力学和动力学的研究. 在N₂气氛下, MC₂O₄•2H₂O(M=Mn、Fe、Co、Ni、Zn)脱水温度Tde和脱水焓ΔdeHm随原子序数Zre递增呈现明显的“二分组效应”；ΔdeHm在(96.46±7.00) kJ•mol^-1范围内波动；MC₂O₄•2H₂O (M=Mn、Fe、Ni)的分解温度Td随原子序数递增呈现良好的线性关系；且各草酸盐分解得到氧化物(CuC₂O₄生成Cu、CuO混合物)时, MC₂O₄(M=Co、Ni、Cu) 分解焓随原子序数增大也存在良好的线性关系. 各草酸盐除NiC₂O₄•2H₂O脱水过程和FeC₂O₄分解过程外, 其余各过程机理函数均为随机成核和随后成长型.     

2-氨基-4，6-二甲氧基嘧啶的低温热容和热力学性质研究

通过精密自动绝热量热计测定了自行合成并提纯的2-氨基-4，6-二甲氨基嘧啶 在78-394 K温区的摩尔热容。实验结果表明，该化合物有一个固-液溶化相变，其 熔化温度、摩尔熔化焓以及摩尔熔化熵分别为：（370.97 ± 0.02）K，（29853. 91 ± 9.25） J·mol~(-1)和（80.45 ± 0.03）J·mol~(-1) · K~(-1)。通过分 步熔化法得到样品的纯度为0.9984 (摩尔分数)和绝对纯样品的熔点为371.031 K。 在热容测量的基础上计算出了该物质每隔5K的热力学函数值。DSC技术对基固-溶熔 化过程作了进一步研究，结果与热容试验相一致。     

陆英提取物乌索酸的热分析研究

用差示扫描量热法(DSC)和热重-微分热重法(TG-DTG)对静态空气气氛的乌索酸进行了热分析研究,为热分析鉴别乌索酸提供了实验依据.结果表明,加热到251℃时质量损失约3.31%,251～341 ℃时质量损失约68.09%,341～464 ℃时质量损失约27.70%,到464℃时质量仅余约0.90%.在158、311、415℃分别有3个放热峰.     

二甲基-二(3-乙炔基苯胺)硅烷的固化反应及其动力学

利用非等温差示扫描量热法(DSC)得到了二甲基-二(3-乙炔基苯胺)硅烷(DMEAS)的特征固化参数,采用Kissinger和Ozawa法计算得到DMEAS固化反应表观活化能(ΔE)分别为100.6、113.0 kJ/mol;通过FT-IR研究了DMEAS固化前后的结构变化,采用TGA分析了其固化物的耐热性。结果表明:DMEAS固化反应主要是乙炔基发生交联反应,形成空间网状结构;在氮气中,DMEAS固化物的热降解起始温度(Td5)为563℃,900℃时的质量残留率为84.0%。     

差示扫描量热法研究寡糖链对糖蛋白的热力学性质的影响

报道了研究寡糖链对糖蛋白热力学性质影响的新方法;以小麦胚芽为原料,从其水溶性提取物中分离得到粗蛋白-糖复合物,经DEAE-Cellulose 52和Seplmdex G-100柱层析,得到一种糖蛋白(WGGP);采用差示扫描量热法(DSC)分别对WGGP和去糖基化的WGGP的热力学参数进行了测定,二者的tp分别为96.098℃和74.338℃,说明WGGP的寡糖链对于蛋白质具有较好的稳定和抗变性功能。     

含CL-20的改性双基推进剂的热行为及非等温反应动力学

用DSC和TG方法研究了含六硝基六氮杂异伍兹烷(CL-20)的改性双基推进剂在常压(0.1 MPa)和高压(4和7 MPa)下的热行为和高压下的热分解反应动力学. 结果表明, 该推进剂常压下DSC曲线有3个放热峰, 相应TG曲线有3个失重过程; 而高压下DSC曲线只有一个放热峰, 高压下放热峰的峰温随加热速率增大而升高. 高压下该推进剂放热分解反应机理和反应动力学参数受测试环境压强影响较弱, 反应机理是随机成核和随后生长, 放热分解反应的动力学方程可以表示为, 4 MPa时, dα/dt=1014.5(1-α)[-ln(1-α)]1/3e-17981.7/T; 7 MPa时, dα/dt=1014.7(1-α)·[-ln(1-α)]1/3e-18138.1/T.     

差示扫描量热法对味精中L-谷氨酸钠的分析

采用差示扫描量热法(DSC)研究了一水谷氨酸钠的热分解过程,结果表明一水谷氨酸钠的热分解过程分为两个阶段,在155℃开始脱去结晶水,脱结晶水阶段动力学参数n=0.89,Ea1=152.8kJ·mol-1,A1=7.8×1018s-1,分子内脱水阶段动力学参数n=0.75,Ea2=274.4kJ·mol-1,A2=1.1×1030s-1,半寿命期为t1/2=1.3×109月。     

4-甲氟基香豆素衍生物的热力学特性研究

This paper describes the DSC study of 4-trifluorocoumarin derivatives, C_(481), C_(485), C_(500) and C_(480), providing their DSC thermograms and thermodynamic parameters during the phase transitions of these compounds. Singlemelting peaks were observed on DSC thermogram respectively.Experimental results show the existence of certain correlations between the melting point, heat of fusion and molecular structure for this series of compounds.     

DSC测量中校正对热分析结果的影响

介绍了灵敏度及温度校正对基线和实验结果的影响.仪器温度和灵敏度校正可以减小差示扫描量热法(DSC)曲线的漂移,曲线上得到的温度和焓变值更接近理论值,减小了实验误差.所以,定期对仪器进行重新校正是必要的.     

差示扫描量热研究水稻线粒体能量释放动力学

线粒体是细胞的一个重要的亚细胞器．它通过呼吸作用为细胞各项活动提供能量，有细胞'动力戒'之称．生物摄取的食物通过代谢分解形成小分子产物之后，被输送至线粒体，经过氧化作用将其中贮存的能量逐步释放出来，并转化为三磷酸腺苦（ATP）以供生命机体各种活动的需要，因而它     

Thermal decomposition kinetics of M (mnt) (5-NO2-phen) (M=Co, Cu, Zn) complexes

Studies of the non-isothermal decomposition of M (mnt) (5-NO₂-phen) (M=Co^II, Cu^II, Zn^II) were carried out by thermogravimetry. The thermal decomposition mechanisms and associated kinetics have been investigated. The kinetic parameters were obtained from an analysis of the TG–DTG curves by integral and differential methods. The most probable kinetic model functions were suggested by comparison of the kinetic parameters. Mathematical expressions for the kinetic compensation effect were derived.     

Phase Transitions in Crystalline [M(H2O)6](ClO4)2 (M=Mg,Mn, Fe,Co, Ni,Cu, Zn,Cd and Hg)

The results of DSC measurements in the temperature range 140–370 K on nine crystalline compounds of the type [M(H₂O)₆](ClO₄)₂, where M=Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd and Hg, are discussed. Anomalies detected in the DSC curves are related to the existence of solid-solid phase transitions and/or to the melting points of these compounds. In consequence of two different hypothetical structural modifications of [Fe(H₂O)₆](ClO₄)₂, two DSC curves are obtained. For the compounds with M=Fe, Cd and Hg, new phase transitions have been discovered. The transition temperatures of the other phase transitions are in good agreement with literature data obtained by adiabatic calorimetry. For the compounds with M=Mg, Ni and Cd, DTA measurements were also carried out and the melting points of theses compounds were established. This revised version was published online in August 2006 with corrections to the Cover Date.     

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.     

Magnetische Eigenschaften der Verbindungen BaMF4 und Pb2 MF6 (M=Mn,Fe, Co,Ni, Cu,Zn)

Zusammenfassung In den beiden untersuchten Doppelfluorid-Serien, BaMF₄ und Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn), zeigen die Verbindungen des Cu und des Zn ein anderes Verhalten als die übrigen. Die Zn-Verbindungen sind diamagnetisch, die Cu-Verbindungen paramagnetisch. Pb₂CuF₆ befolgt dasCuriesche Gesetz, während BaCuF₄ eineCurie-Weiss-Abweichung unterhalb 212 K aufweist.Im untersuchten Temperaturbereich zeigt sich für alle anderen Verbindungen, mit Ausnahme von Pb₂FeF₆, Antiferromagnetismus.

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Magnetic properties of the compounds BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn)

Two series of double fluorides, BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn) have been studied, the compounds of Cu and Zn differing in behaviour from the others. The Zn componds are diamagnetic, the Cu compounds paramagnetic. Pb₂CuF₆ conforms toCurie's law while BaCuF₄ exhibits aCurie-Weiss deviation below 212° K.With the exception of Pb₂FeF₆, all the other compounds show antiferromagnetism in the studied temperature range.

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Mit 5 Abbildungen

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Herrn Prof. Dr.Hans Nowotny ergebenst gewidmet.     

[MPy4(NCO)2]-2Py clathrates (M = M(II) = Mn,Fe, Co,Ni, Cu,Zn, Cd; Py = pyridine)

The title compounds form an iso structural series and are isomorphic with other [MPy₄X₂]-2Py clathrates (XRD, KM4 diffractometer, cell parameters and space group Ccca from 17–80 reflections). In the clathrate [NiPy₄(NCO)₂]-2Py studied in detail (XRD, CAD-4 diffractom eter, λCuK_α, Ω/2θ scan mode, θ_max = 78‡, 990 strong reflections, 104 parameters, R = 0.053), the host molecule has 222 symmetry, and the twofold axes run along the coordination bonds. The transoctahedral environment of nickel consists of six nitrogen atoms of four pyridine and two isocyanate ligands. The coordination polyhedron is slightly distorted due to changes in the bond lengths. The molecule has a propeller conformation. The guest molecules lie in the cavities of the crystal structure in conformity with the van der Waals type of packing. The host complex [NiPy₄(NCO)₂] (XRD, CAD-4 diffractometer, 4615 strong reflections, 560 parameters, R-0.037) crystallizes in the triclinic crystal system (space group P1) with two independent asymmetric molecules in the unit cell. The molecular structure is analogous to that in the ciathrate phase, but the coordination angles are severely distorted; one of the molecules acquires a distorted propeller conformation, and the other, a centrosvmmetric conformation, which is less favorable. While being structurally identical, the [MPy₄(NCO)₂]-2Py clathrates differ heavily in the properties. The first four complexes dissociate to host complexes, and their thermal stability changes in the sequence Mn< Fe< Co< Ni; the Cu and Zn clathrates decompose in one step to dipyridine complexes with decomposition of host complexes. Decomposition of the Cd ciathrate follows one of these patterns depending on conditions. The results are compared with those for other known systems. Synthetic procedures are given. Translated fromZhurnal Strukturnoi Khimii, Vol. 40, No. 5, pp. 935–953, September–October, 1999.     

Cyano-bridged hexanuclear Fe4M2 (M = Ni, Co, Mn) clusters: spin-canted antiferromagnetic ordering of Fe4Ni2 cluster

Heterobimetallic hexanuclear cyano-bridged complexes, [{Fe(Tp)(CN)3}4{M(MeCN)(H2O)2}(2)].10H2O.2MeCN [M = Ni (1), Co (2), Mn (3); Tp = hydrotris(1-pyrazolyl)borate], have been synthesized in H2O-MeCN solution. Complexes 1-3 are isostructural and hexanuclear with [{Fe(Tp)(CN)3}4{M(MeCN)(H2O)2}2] units linked by hydrogen bonds to form a 2D-structure in the solid state. Complex 1 is a canted antiferromagnet that undergoes a field-induced spin-flop-like transition at approximately 1 T and 2 K. At 4.45 K 1 has a transition to paramagnetic state of noninteracting S = 4 magnetic clusters. However, 2 and 3 show antiferromagnetic intracluster coupling. Facile loss of solvent from 2 alters the local symmetry resulting in changing the intracluster interaction from antiferro- to ferromagnetic.     

MAPO-CHA(M=Mn,Fe,Co,Zn)系列过渡金属取代磷酸铝化合物的合成、结构与性质

在水热体系中, 以2-胺乙基哌嗪分解得到的二乙胺为模板剂, 合成了一系列具有CHA结构的过渡金属取代磷酸铝化合物MAl(PO₄)₂[(C₂H₅)₂NH₂](命名为MAPO-CHA, M=Mn, Fe, Co, Zn), 其M/Al原子比为1. 单晶结构分析表明, MnAPO-CHA晶体属于三方晶系, R3空间群, 晶胞参数a=1.4003(2)nm, c=1.5236(3) nm, V=2.5873(7) nm³, Z=9, 其无机骨架由Al(Mn)O₄四面体和PO₄四面体交替连接形成具有分子筛CHA的拓扑结构, 单质子化的二乙胺离子位于八元环孔道中. X射线粉末衍射分析表明, 这些化合物是同构的, 并均具有荧光性质, 其中, 化合物MAPO-CHA(M=Mn, Fe, Co)还具有弱的反铁磁交换作用.     

Hydrogen storage in the dehydrated prussian blue analogues M3[Co(CN)6]2 (M = Mn, Fe, Co, Ni, Cu, Zn)

The porosity and hydrogen storage properties for the dehydrated Prussian blue analogues M3[Co(CN)6]2 (M = Mn, Fe, Co, Ni, Cu, Zn) are reported. Argon sorption isotherms measured at 87 K afford BET surface areas ranging from 560 m2/g for Ni3[Co(CN)6]2 to 870 m2/g for Mn3[Co(CN)6]2; the latter value is comparable to the highest surface area reported for any known zeolite. All six compounds show significant hydrogen sorption at 77 K and 890 Torr, varying from 1.4 wt % and 0.018 kg H2/L for Zn3[Co(CN)6]2 to 1.8 wt % and 0.025 kg H2/L for Cu3[Co(CN)6]2. Fits to the sorption data employing the Langmuir-Freundlich equation give maximum uptake quantities, resulting in a predicted storage capacity of 2.1 wt % and 0.029 kg H2/L for Cu3[Co(CN)6]2 at saturation. Enthalpies of adsorption for the frameworks were calculated from hydrogen isotherms measured at 77 and 87 K and found to increase with M varying in the order Mn < Zn < Fe < Co < Cu < Ni. In all cases, the binding enthalpies, which lie in the range of 5.3-7.4 kJ/mol, are higher than the 4.7-5.2 kJ/mol measured for Zn4O(1,4-benzenedicarboxylate)3.