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1.
Core/shell composites of CuC2O4·2H2O@AP and ZnC2O4·2H2O@AP were prepared from metal oxalates on suspended AP particles in ethanol. CuO and ZnO nano-metal oxides as the nano-catalysts were made from CuC2O4·2H2O and ZnC2O4·2H2O simultaneously by thermal decomposition of AP. The particle size of CuO nano-particles was very finer, and the ZnO particles showed a considerable growth during formation. The kinetic triplet of activation energy, frequency factor, and model of thermal decomposition of pure AP, CuC2O4·2H2O@AP, and ZnC2O4·2H2O@AP composites were estimated by applying three model-free (FWO, KAS, and Starink) and model-fitting (Starink) methods. Based on the thermal analysis, the CuC2O4@AP composite has better catalytic performance and the thermal decomposition temperature of AP decreased to about 126.44 °C.  相似文献   

2.
The spinel Mn0.5Mg0.5Fe2O4 was obtained via calcining Mn0.5Mg0.5Fe2(C2O4)3·5H2O above 400 °C in air. The precursor and its calcined products were characterized by thermogravimetry and differential scanning calorimetry, Fourier transform FT-IR, X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectrometer, and vibrating sample magnetometer. The results showed that Mn0.5Mg0.5Fe2O4 obtained at 600 °C had a specific saturation magnetization of 46.2 emu g–1. The thermal decomposition of Mn0.5Mg0.5Fe2(C2O4)3·5H2O below 450 °C experienced two steps which involved, at first, the dehydration of five water molecules and then decomposition of Mn0.5Mg0.5Fe2(C2O4)3 into spinel Mn0.5Mg0.5Fe2O4 in air. Based on Starink equation, the values of the activation energies associated with the thermal decomposition of Mn0.5Mg0.5Fe2(C2O4)3·5H2O were determined.  相似文献   

3.
Reactions of 1,10‐phenanthroline monohydrate, Na2C4H4O4 · 6 H2O and MnSO4 · H2O in CH3OH/H2O yielded a mixture of [Mn2(H2O)4(phen)2(C4H4O4)2] · 2 H2O ( 1 ) and [Mn(phen)2(H2O)2][Mn(phen)2(C4H4O4)](C4H4O4) · 7 H2O ( 2 ). The crystal structure of 1 (P1 (no. 2), a = 8.257(1) Å, b = 8.395(1) Å, c = 12.879(2) Å, α = 95.33(1)°, β = 104.56(1)°, γ = 106.76(1)°, V = 814.1(2) Å3, Z = 1) consists of the dinuclear [Mn2(H2O)4(phen)2(C4H4O4)2] molecules and hydrogen bonded H2O molecules. The centrosymmetric dinuclear molecules, in which the Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms from two H2O molecules and two bis‐monodentate succinato ligands, are assembled via π‐π stacking interactions into 2 D supramolecular layers parallel to (101) (d(Mn–O) = 2.123–2.265 Å, d(Mn–N) = 2.307 Å). The crystal structure of 2 (P1 (no. 2), a = 14.289(2) Å, b = 15.182(2) Å, c = 15.913(2) Å, α = 67.108(7)°, β = 87.27(1)°, γ = 68.216(8)°, V = 2934.2(7) Å3, Z = 2) is composed of the [Mn(phen)2(H2O)2]2+ cations, [Mn(phen)2(C4H4O4)] complex molecules, (C4H4O4)2– anions, and H2O molecules. The (C4H4O4)2– anions and H2O molecules form 3 D hydrogen bonded network and the cations and complex molecules in the tunnels along [001] and [011], respectively, are assembled via the π‐π stacking interactions into 1 D supramolecular chains. The Mn atoms are octahedrally coordinated by four N atoms of two bidentate chelating phen ligands and two water O atoms or two carboxyl O atoms (d(Mn–O) = 2.088–2.129 Å, d(Mn–N) = 2.277–2.355 Å). Interestingly, the succinato ligands in the complex molecules assume gauche conformation bidentately to chelate the Mn atoms into seven‐membered rings.  相似文献   

4.
纳米Co3O4具有尖晶石结构,Co3 占据八面体位,具有较高的晶体场稳定化能,在空气中低于800℃时十分稳定,是优良的催化材料[1]。Co3O4还可以作为高比能锂离子电池负极材料具有非常好的电化学活性,充放电容量高达960m A h·g-1。纳米Co3O4在紫外、可见及近红外区域都有良好的吸收效果,因此,在隐身技术、保温节能技术等领域具有潜在的应用前景。所以,Co3O4超细粉体的制备和应用研究具有十分重要的意义。我们合成了草酸盐先驱物制备纳米Co3O4用作隐身材料,因此对先驱物的热分解过程研究是十分必要的。热分析方法在了解先驱物热分解反应的物理…  相似文献   

5.
Reaction of MnSO4 · H2O, 2,2′‐bipyridine (bpy), suberic acid and Na2CO3 in CH3OH/H2O yielded a mixture of [Mn2(H2O)4(bpy)2(C8H12O4)2] · 2 H2O ( 1 ) and [Mn(H2O)2‐ (bpy)(C8H12O4)2/2] · H2O ( 2 ). In both complexes, the Mn atoms are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two trans positioned H2O molecules and two suberato ligands (d(Mn–O) = 2.107–2.328 Å; d(Mn–N) = 2.250–2.330 Å). The bis‐monodentate suberato ligands bridge Mn atoms to form dinuclear [Mn2(H2O)4(bpy)2(C8H12O4)2] complex molecules in 1 and 1D [Mn(H2O)2(bpy)(C8H12O4)2/2] chains in 2 . Via the intermolecular hydrogen bondings and π‐π stacking interactions, the dinuclear molecules in 1 are assembled into 2D networks parallel to (100), between which the crystal H2O molecules are sandwiched. The polymeric chains in 2 are linked together by interchain hydrogen bonding and π‐π stacking interactions into 3D networks with the crystal H2O molecules located in tunnels along [010]. Crystal data for 1 : P21/c (no. 14), a = 10.092(1) Å, b = 11.916(2) Å, c = 17.296(2) Å, β = 93.41(1)° and Z = 2. Crystal data for 2 : P21/c (no. 14), a = 11.176(2) Å, b = 9.688(1) Å, c = 37.842(6) Å, β = 90.06(1)° and Z = 8.  相似文献   

6.
Two supramolecular architectures, [Mn(3‐bpd)2(NCS)2(H2O)2]·2H2O ( 1 ) and {[Mn(bpe)(NCS)2(H2O)2]·(3‐bpd)·(bpe)·H2O}n ( 2 ) [bpe = 1,2‐bis(4‐pyridyl)ethylene and 3‐bpd = 1,4‐bis(3‐pyridyl)‐2,3‐diaza‐1,3‐butadiene] have been synthesized and characterized by spectroscopic, elemental and single crystal X‐ray diffraction analyses. Compound 1 crystallizes in the monoclinic system, space group P21/c, with chemical formula C26H28Mn N10O4S2, a = 9.1360(6), b = 9.7490(6), c = 17.776(1) Å, β = 93.212(1)°, and Z = 2 while compound 2 crystallizes in the orthorhombic system, space group P212121, with chemical formula C38H36Mn1N10O3S2, a = 14.1902(6), b = 15.4569(7), c = 18.2838(8) Å, α = β = γ = 90°, and Z = 4. Structural determination reveals that the coordination geometry at Mn(II) in compound 1 or 2 is a distorted octahedral which consists of two nitrogen donors of two NCS?ligands, two oxygen donors of two water molecules, and two nitrogen donors of two 3‐bpd ligands for 1 and two dpe ligands for 2 , respectively. The two 3‐bpd ligands in 1 adopt a monodentate binding mode and the dpe in 2 adopts a bismonodentate bridging mode to connect the Mn(II) ions forming a 1D chain‐like coordination polymer. Both the π‐π stacking interactions between the coordinated and the free pyridyl‐based ligands and intermolecular hydrogen bonds among the coordinated and the crystallized water molecules and the free pyridyl‐based ligands play an important role in construction of these 3D supramolecular architectures.  相似文献   

7.
The energetic complex, [Co(2,4,3‐tpt)2(H2O)2] · 2NO3 ( 1 ) [2,4,3‐tpt = 3‐(2‐pyridyl)‐ 4‐(4'‐pyridyl)‐5‐(3′‐pyridyl)‐1H‐1,2,4‐triazole], was synthesized and characterized by single‐crystal X‐ray diffraction, thermogravimetric analyses, elemental analysis, X‐ray powder diffraction, and IR spectroscopy. The title complex is a 0D motif with a unit of [Co(2,4,3‐tpt)2(H2O)2]2+, whereas NO3 ions not only act as counter anions to balance the charge of the CoII cations, but also provide hydrogen bond interactions, which make the 0D motif into a 1D chain. Furthermore, the thermal decomposition of ammonium perchlorate (AP) with complex 1 was explored by differential scanning calorimetry (DSC) over the temperature range from 50–500 °C. AP is completely decomposed in a shorter time in the presence of complex 1 , and the decomposition heat of the mixture is 2.143 kJ g–1, significantly higher than pure AP. By Kissinger's method, the ratio of Ea/ln(A) is 11.87 for the mixture, which indicates that complex 1 shows good catalytic activity toward AP decomposition.  相似文献   

8.
TG-DTG technique and Harcourt-Esson integrated equation were used to study the dehydration process of zinc phosphate tetrahydrate α-Zn3(PO4)2·4H2O nanoparticle and its thermal decomposition kinetics. The results show that there are three stages of dehydration between 300 and 800 K during the thermal decomposition of α-Zn3(PO4)2·4H2O nanoparticle. The first stage is controlled by chemical reaction with an activation energy of 69.48 kJ·mol^-1 and a pre-exponential factor of 1.77×10^6 s^-1. The second is controlled by nucleation and growth with an activation energy of 78.74 kJ·mol^-1 and a pre-exponential factor of 5.86×10^9 s^-1. The third is controlled by nucleation and growth with an activation energy of 141.5 kJ·mol^-1 and a pre-exponential factor of 1.01×10^12 s^-1. The kinetic compensative effects not only exist in Arrhenius equation but also in Harcourt-Esson equation. Activation energy E is dependent on both the decomposition fraction α and temperature T.  相似文献   

9.
张忠海  库宗军  刘义  屈松生 《中国化学》2005,23(9):1146-1150
以氯化镝、甘氨酸和L-酪氨酸为原料合成了配合物Dy(Tyr)(Gly)3Cl3·3H2O. 用溶解-反应热量计测得配合物在298. 15K时的标准摩尔生成焓为–(4287. 10±2. 14) kJ / mol. 并用TG-DTG技术对配合物进行了非等温热分解动力学研究, 推断出配合物第二步热分解反应的动力学方程为: dα/dT=3. 14 ×1020 s-1/βexp(-209. 37 kJ / mol /RT)(1-α)2.  相似文献   

10.
The effect of ferric and manganese oxides dopants on thermal and physicochemical properties of Mn-oxide/Al2O3 and Fe2O3/Al2O3 systems has been studied separately. The pure and doped mixed solids were thermally treated at 400–1000°C. Pyrolysis of pure and doped mixed solids was investigated via thermal analysis (TG-DTG) techniques. The thermal products were characterized using XRD-analysis. The results revealed that pure ferric nitrate decomposes into Fe2O3 at 350°C and shows thermal stability up to1000°C. Crystalline Fe3O4 and Mn3O4phases were detected for some doped solids precalcined at 1000°C. Crystalline γ-Al2O3 phase was detected for all solids preheated up to 800°C. Ferric and manganese oxides enhanced the formation of α-Al2O3 phase at1000°C. Crystalline MnAl2O4 and MnFe2O4 phases were formed at 1000°C as a result of solid–solid interaction processes. The catalytic behavior of the thermal products was tested using the decomposition of H2O2 reaction. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

11.
The title compound, {[Mn(C4H4O6)(C12H8N2)]·6H2O}n, has a linear chain structure containing monomeric [Mn(C4H4O6)(C12H8N2)] repeat units. Each manganese ion is six‐coordinate, with the two phenanthroline N atoms [Mn—N = 2.229 (2) and 2.235 (2) Å] and four O atoms from two tartrate anions [Mn—OCOO = 2.1252 (19) and 2.1310 (19) Å, and Mn—OOH = 2.2404 (19) and 2.2424 (19) Å] forming a seriously distorted octahedral coordination environment. Six water mol­ecules exist outside every repeat unit as solvate mol­ecules. Extensive hydrogen‐bonding interactions and π–π stacking of the phenanthroline moieties exist between the chains.  相似文献   

12.
Two coordination compounds [Pb4(BDT)3(OH)2(H2O)4]·H2O ( 1 ) and [Mn(H2O)6]·(HBDT)2·2H2O ( 2 ) [H2BDT?5,5′‐(1,4‐phenylene)bis(1H‐tetrazole)] had been hydrothermally synthesized. 1 and 2 had been characterized by single‐crystal X‐ray diffraction, IR, elemental and thermal analyses. Structural analysis reveals that 1 exhibits 2D layer structure extended through BDT with two different coordination modes rings in transverse and vertical. 2 consists of [Mn(H2O)6]2+, free HBDT and water. In addition, 1 and 2 were explored as luminescent materials and additives to promote the thermal decomposition of ammonium perchlorate by differential scanning calorimetry.  相似文献   

13.
Investigation of Cocrystallization in the Systems Mn(OOCCH3)2-Co(OOCCH3)2-H2O, Mn(OOCCH3)2-Ni(OOCCH3)2-H2O, Mn(OOCCH3)2-Zn(OOCCH3)2-H2O at 60°C The three-component systems Mn(OOCCH3)2-Co(OOCCH3)2-H2O, Mn(OOCCH3)2-Ni(OOCCH3)2-H2O and Mn(OOCCH3)2-Zn(OOCCH3)2-H2O at 60°C were investigated by physio-chemical analysis. There is an interruption in the series of mixed crystals formed in the three-component systems. The inclusion of Co2+- and Ni2+ in Mn(OOCCH3)2 · 2 H2O of Mn2+ in Co(OOCCH3)2 · 2 H2O, Zn(OOCCH3)2 · 2 H2O and Ni(OOCCH3)2 · 4 H2O is based on isodimorphic substitution. It was found that in the system Mn(OOCCH3)2-Zn(OOCCH3)2-H2O crystallizes Zn(OOCCH3)2 · Mn(OOCCH3)2 · 2 H2O. It was identified by the X-ray and differential thermal analysis.  相似文献   

14.
The non-isothermal decomposition kinetics of 4Na2SO4·2H2O2·NaCl have been investigated by simultaneous TG-DSC in nitrogen atmosphere and in air. The decomposition processes undergo a single step reaction. The multivariate nonlinear regression technique is used to distinguish kinetic model of 4Na2SO4·2H2O2·NaCl. Results indicate that the reaction type Cn can well describe the decomposition process, the decomposition mechanism is n-dimensional autocatalysis. The kinetic parameters, n, A and E are obtained via multivariate nonlinear regression. The n th-order with autocatalysis model is used to simulate the thermal decomposition of 4Na2SO4·2H2O2·NaCl under isothermal conditions at various temperatures. The flow rate of gas has little effect on the decomposition of 4Na2SO4·2H2O2·NaCl.  相似文献   

15.
On the refluxing ofM(II) oxalate (M=Mn, Co, Ni, Cu, Zn or Cd) and 2-ethanolamine in chloroform, the following complexes were obtained: MnC2O4·HOCH2CH2NH2·H2O, CoC2O4·2HOCH2CH2NH2, Ni2(C2O4)2·5HOCH2CH2NH2·3H2O, Cu2(C2O4)2·5HOCH2CH2NH2, Zn2(C2O4)2·5HOCH2CH2NH2·2H2O and Cd2(C2O4)2·HOCH2CH2NH2·2H2O. Following the reaction ofM(II) oxalate with 2-ethanolamine in the presence of ethanolammonium oxalate, a compound with the empirical formula ZnC2O4·HOCH2CH2NH2·2H2O1 was isolated. The complexes were identified by using elemental analysis, X-ray powder diffraction patterns, IR spectra, and thermogravimetric and differential thermal analysis. The IR spectra and X-ray powder diffraction patterns showed that the complexes obtained were not isostructural. Their thermal decompositions, in the temperature interval between 20 and about 900°C, also take place in different ways, mainly through the formation of different amine complexes. The DTA curves exhibit a number of thermal effects.  相似文献   

16.
The imidazole covalently coordinated sandwich‐type heteropolytungstates Na9[{Na(H2O)2}3{M(C3H4N2)}3‐ (SbW9O33)2xH2O (M=NiII, x=32; M=CoII, x=32; M=ZnII, x=33; M=MnII, x=34) were obtained by the reaction of Na2WO4·2H2O, SbCl3·6H2O, NiCl2·6H2O [MnSO4·H2O, Co(NO3)2·6H2O, ZnSO4·7H2O] and imidazole at pH≈7.5. The structure of Na9[{Na(H2O)2}3{Ni(C3H4N2)}3(SbW9O33)2]·32H2O was determined by single crystal X‐ray diffraction. Polyanion [{Na(H2O)2}3{Ni(C3H4N2)}3(SbW9O33)2}3]9? has approximate C3v symmetry, imidazole coordinated six‐nuclear cluster [{Na(H2O)2}3{Ni(C3H4N2)}3]9+ is encapsulated between two (α‐SbW9O33)9?, the three rings of imidazole in the polyanion are perpendicular to the horizontal plane formed by six metals (Na‐Ni‐Na‐Ni‐Na‐Ni) in the central belt, and π‐stacking interactions exist between imidazoles of neighboring polyanions with dihedral angel of 60°. The compounds were also characterized by IR, UV‐Vis spectra, TG and DSC, and the thermal decomposition mechanism of the four compounds was suggested by TG curves.  相似文献   

17.
A novel ammonium perchlorate (AP)/aluminum (Al)/iron oxide (Fe2O3) nano-thermites was prepared by orderly using sol–gel, wet impregnation, and solvent-anti-solvent processes. Samples prepared in this work were characterized by scanning electron microscope (SEM), nitrogen adsorption–desorption tests, X-ray diffraction (XRD), and differential scanning calorimetric (DSC) measurements. The results showed that AP and nano-aluminum were dispersed in the pores of the iron oxide gel, resulting in a large specific surface area (84.7 m2 g?1). The XRD results showed that AP dispersed homogeneously in the energetic composites at nano-scale. DSC analyses indicate that the Al/Fe2O3 nano-thermites played a catalytic role in the thermal decomposition of AP, thus the interaction of thermite reaction was greatly enhanced by accelerated decomposition of AP. The experimental results showed that the as-prepared AP/Al/Fe2O3 nano-thermites were of high energy, making it a competitive candidate material in the field of micro-propellants.  相似文献   

18.
汪敦佳  方正东  魏先红 《中国化学》2005,23(12):1600-1606
A new polyoxometalate (CPFX·HCl)3H4SiW12O40·10H2O was prepared from ciprofloxacin hydrochloride and H4SiW12O40·nH2O in aqueous solution, and characterized by elemental analysis, IR spectra and DTA-TG-DTG techniques. The IR spectrum confirmed the presence of Keggin structure and the characteristic functional group for ciprofloxacin in the compound. The TG-DTA-DTG curves showed that its thermal decomposition was a four-step process consisting of simultaneous collapse of Keggin type structure. The residue of decomposition was the mixture of WO3 and SiO2, confirmed by X-ray diffraction and IR spectroscopy. The decomposition mechanism and nonisothermal kinetic parameters of the polyoxometalate were obtained from an analysis to the TG-DTG curves by the single scanning methods (the Achar method and Coats-Redfern method) and the multiple scanning methods (the Kissinger method, Flynn-Wall-Ozawa method and Starink method). The results indicate that the kinetic equationswith parameters describing the thermal decomposition reaction are dα/dt=6.65×10^6[3(1-α)^2/3]e^-10495.5/T with E=87.26 kJ/mol and A=6.65×10^6 s^-1 for the second step,dα/dt=7.01×10^9(1-α)e^-18770.7/T with E=156.06 kJ/mol and A=7.01×10^9 s^-1 for the third step,dα/dt=9.77×10^43[(1-α)^2]e^-88980.0/T with E=739.78 kJ/mol and A=9.77×10^43 s^-1 for the fourth step.  相似文献   

19.
《Solid State Sciences》2012,14(8):1045-1049
Binary and ternary microstructure composites based on CNTs have potential applications in many technological fields. In our works, we realized MWCNTs-bridged architecture of ternary Bi2O3/MWCNTs/Cu microstructure composite by two-step self-assembly. In order to verify its workability, we investigated catalytic performances of a series of additives for ammonium perchlorate (AP) thermal decomposition. The results showed that catalytic performance of Bi2O3/MWCNTs/Cu composite was better than those of the other additives, and the peak temperature for high-temperature AP decomposition reduced 151.6 °C; while no low-temperature AP decomposition was observed. MWCNTs have two crucial roles in catalytic enhancement on AP thermal decomposition: firstly, being to act as a supporter which can effectively disperse copper and Bi2O3 particles; secondly, being to act as a bridge, excited electrons from semiconductor can conduct and store on the surfaces of MWCNTs, which is beneficial for AP thermal decomposition. Therefore, MWCNTs-bridged architecture can synergistically enhance catalytic effect of copper and Bi2O3.  相似文献   

20.
This study is devoted to the thermal decomposition of ZnC2O4·2H2O, which was synthesized by solid-state reaction using C2H2O4·2H2O and Zn(CH3COO)2·2H2O as raw materials. The initial samples and the final solid thermal decomposition products were characterized by Fourier transform infrared and X-ray diffraction. The particle size of the products was observed by transmission electron microscopy. The thermal decomposition behavior was investigated by thermogravimetry, derivative thermogravimetric and differential thermal analysis. Experimental results show that the thermal decomposition reaction includes two stages: dehydration and decomposition, with nanostructured ZnO as the final solid product. The Ozawa integral method along with Coats–Redfern integral method was used to determine the kinetic model and kinetic parameters of the second thermal decomposition stage of ZnC2O4·2H2O. After calculation and comparison, the decomposition conforms to the nucleation and growth model and the physical interpretation is summarized. The activation energy and the kinetic mechanism function are determined to be 119.7 kJ mol?1 and G(α) = ?ln(1 – α)1/2, respectively.  相似文献   

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