WO3在γ-Al2O3表面的分散状态和最大分散量

应用X光衍射法(XRD)测定了WO2/γ-Al2O3体系的物相组成和平均晶粒度,以及该体系的孔容和比表面:应用XRD相定量外推法和光电子能谱(XPS)峰强度比(Iw4f/IA12s)法定量测定了WO3在γ-Al2O3表面的最大分散量,测值分别为0.21和0.20gWO3/100m[2]γ-Al2O3,与按照WO3在γ-Al2O3表面作密置单层排布模型的计算值0.189WO3/100m[2],即4.9x10[18]W原子/m[2])相近,对WO3/γ-Al2O3体系与MoO3/γ-Al2O3体系比较和讨论。     

Synthesis,Crystal Structure and Antitumor Activity in Vitro of a New Benzoate Binuclear Cupper（ Ⅱ） Complex

The title compound, [Cu2（C7H5O2）4（C2H6O）2], was synthesized by the reaction of benzoic acid, copper acetate and ethanol in an aqueous solution. Trypan blue dye exclusion method was used in experiment. X-ray single-crystal analysis has revealed that compound 1 （C32H32Cu2O10） crystallizes in the monoclinic system, space group C2/c, Mr = 703.66, a = 47.340（5）, b = 6.6613（4）, c = 22.028（2）A,β = 113.284（4）°, V = 6380.6（10） A^3, Z = 8, Dc= 1.465 g/cm^3, F（000） = 2896,μ = 1.388 mm^-11, the final R = 0.0515 and wR = 0.1172 for 5712 observed reflections with I 〉 2σ（I）. X-ray crystal structure analysis suggests that compound [CH2（C7H5O2）4（C2H6O）2] has a binuclear structure with two Cu（II） atoms coordinated by four benzoate groups and two ethanol molecules. The crystal packing is stabilized by intermolecular O-H...O hydrogen bonds. The compound inhibits the proliferation of K562 cells （chronic myeloid leukemic cells） significantly and dose-dependently in 48 h, and IC50 of K562 is 17.3μg/mL by trypan blue dye exclusion method.     

Orientations of Rare—earth—containing Heteropolyoxometalates with Different Sizes in the Interlayer of Synthetic Multibilayer Films

Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5O18)2],K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibilayer films of dimethyldioctadecylammonium chloride and exhibited different orientations.     

2，4，6-三硝基间苯二酚钡一水化合物的热分解动力学(英)

0IntroductionBarium2,4,6鄄trinitroresorecinatemonohydrate,Ba(TNR)·H2O,hasgooddetonatingpropertiesandissensitivetoflame.Itcanbeusedasinitiatingagent,igniterpowderordelaypowder.Itspreparation[1],pro鄄perties[1],crystalstructure[1]andthermalbehavior[2]haveb…     

Crystal Structure Analysis of Tetras[L-tris(ethylenediamine) cobalt(Ⅲ)] tris[hexacyanoruthenate(Ⅱ)]

1 INTRODUCTION The tris(ethylenediamine) cobalt (Ⅲ) complex in which there are L and D configurations is one of the very interest cations due to the chirality among research complexes and the characterization of reaction on the ion-pair charge-transfer transitions. It has been mentioned in a lot of examples on the chirality and the structure, such as [L-Co(en)3]- [?Co(edta)]2Cl?0H2O[1], [(+)DCo(en)3]Cl3稨2O[2], [(+)-Co(en)3?-)-Cr(en)3]Cl?.1H2O[3], [()-Co(en)3] (SCN)3[4], [(+)D…     

α-(+)-Co(en)3V3O9*H2O的合成与表征

由于聚氧酸盐在催化、制药和阳离子电极等方面具有潜在的应用价值[1～3], 因此一直是无机化学研究的热点[4～8], 自1993年具有双螺旋结构的化合物[(CH3)2NH2]K4[V10O10(H2O)2(OH)4(PO4)7]*4H2O[9]被合成以来, 更多的关注集中在聚氧酸盐的合成及结构研究中.     

铁取代钨硅酸盐位置异构体的合成、表征及电化学性质

取代型杂多酸盐（ HPC）具有金属卟啉的类似结构 ,它可以代替金属卟啉在很多反应中作催化剂 [1],被称为无机金属卟啉。 Hill[2],Neumann[3]分别报道了过渡元素单取代的杂多阴离子 [PW11M(H2O)O39]n－, [SiW11Ru(H2O)O39]n－对烯烃环氧化反应具有催化活性。目前,在单取代的杂多配合物中,β异构体的报道很少,我们发现,某些单取代金属衍生物中,β异构体具有良好的催化活性,具有明显的应用前景。继过去的工作 [4],我们又研究了过渡元素取代的 11-系列杂多阴离子的某些性质。有关α-XW11Fe(H2O)O39n－（ X=Si, P, Ge, As…     

Biomimetic Preparation of Magnetite/Chitosan Nanocomposite via In Situ Composite Method ——Potential Use in Magnetic Tissue Repair Domain

IntroductionMagnetite (Fe3O4) is widespread in the environ-ment although it is thermodynamically unstable with re-spect to hematite(α-Fe2O3) in the presence of oxygen.It has been widely used for targeted delivery ofdrugs[1], in MRI reagents[2], hyperther…     

纳米Sb2O3的制备与性能研究

由于Sb2O3是一种性能优良的无机阻燃剂,并与卤素阻燃剂有很好的协效作用[1],1998年,全球用于阻燃的Sb2O3达80kt以上,占阻燃剂总耗量的7%[2]。但由于其本身的极性特点,加入到纤维、塑料等高分子材料中,材料的力学性能受到很大损失[3],因此对传统的微米级的Sb2O3进行超细、表面处     

Ni(II), Co(II), and Cu(II) complexes incorporating 2-pyrazinecarboxylic acid：Synthesis,characterization, electrochemical evaluation,and catalytic activity for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones

Three complexes containing 2-pyrazinecarboxylate (pzca–), including [Ni(pzca)2(H2O)2], [Co(pzca)2(H2O)2], and [Cu(pzca)2(H2O)2], have been synthesized and characterized using physico-chemical and spectroscopic methods. Furthermore, the structure of each complex was determined by single-crystal X-ray diffraction. All three complexes have an octahedral geometry, where the metal ion chelated by two carboxylate oxygens, two nitrogen atoms belonging to pyrazinic acid molecules, and two oxygen atoms of two water molecules. The catalytic activities of these complex-es were also investigated in the green synthesis of 2H-indazolo[2,1-b]phthalazine-triones by the reaction of hydrazine hydrate with an arylaldehyde, phthalic anhydride, and dimedone in acetic acid.     

Solid-state Al NMR investigation of thermal decomposition of LiAlH4

Solid-state nuclear magnetic resonance is used to study the thermal decomposition of lithium tetrahydroaluminate into metallic aluminum, hydrogen and trilithium hexahydroaluminate. Aluminum sites in LiAlH₄ and Li₃AlH₆ were characterized using static, magic angle spinning (MAS) and multiple-quantum MAS NMR. By applying the in situ NMR method, it has been demonstrated that melting is not a prerequisite for the decomposition of LiAlH₄. Based on the observed data, a decomposition path has been established that is consistent with the concentrations of observed Al species at various stages of the thermally induced reaction.     

Thermal decomposition kinetics of potassium iodate

The thermal decomposition of potassium iodate (KIO₃) has been studied by both non-isothermal and isothermal thermogravimetry (TG). The non-isothermal simultaneous TG–differential thermal analysis (DTA) of the thermal decomposition of KIO₃ was carried out in nitrogen atmosphere at different heating rates. The isothermal decomposition of KIO₃ was studied using TG at different temperatures in the range 790–805 K in nitrogen atmosphere. The theoretical and experimental mass loss data are in good agreement for the thermal decomposition of KIO₃. The non-isothermal decomposition of KIO₃ was subjected to kinetic analyses by model-free approach, which is based on the isoconversional principle. The isothermal decomposition of KIO₃ was subjected to both conventional (model fitting) and model-free (isoconversional) methods. It has been observed that the activation energy values obtained from all these methods agree well. Isothermal model fitting analysis shows that the thermal decomposition kinetics of KIO₃ can be best described by the contracting cube equation.     

Decomposition of hydrogen peroxide in aqueous solutions at elevated temperatures

Decomposition of hydrogen peroxide in high-purity water has been measured at temperatures ranging 100 to 280°C in a laboratory test loop. A first-order decomposition kinetics has been observed in all cases, but the decomposition rates were found to vary widely, depending on the material used in the reaction chamber. In a 4 mm ID stainless steel tubing, the decomposition rate constant is determined to be k = 2 × 10⁵ exp(?14800/RT). This decomposition rate is approximately 100 times faster than that observed in a Teflon tubing. The variation of decomposition rate in different reaction chambers is attributed to the heterogeneous catalytic effects. There is no evidence of reaction between H₂ and H₂O₂ in the highpurity water at temperatures up to 280°C.     

Investigations on thermal stability of adduct aluminium nitrate(V)-urea (1/6)

The adduct of Al(NO₃)₃·6CO(NH₂)₂ has been prepared and characterized by means of chemical analysis, IR spectroscopy, X-ray patterns and microscopy. A thermoanalytical study of Al(NO₃)₃·6CO(NH₂)₂ as well as urea, for comparison purposes, under conventional dynamic and quasi-isothermal—quasi-isobaric conditions in air has been carried out. It has been found that the adduct is thermally stable up to about 200°C, i.e. up to higher temperature than the decomposition temperature of the constituent compounds. The thermal decomposition mechanism of the adduct is complex, thus infrared spectroscopy and X-ray diffraction techniques have been used to determine the intermediate products. Aluminium oxide(III) is the final decomposition product.     

Thermal decomposition of zinc hydroxy azide

The isothermal decomposition of zinc hydroxy azides, Zn(OH)_2-x(N₃)_x: follows deceleratory kinetics throughout the temperature range studied. The initial part of the decomposition fits into unimolecular decay law, log (1-a) = -kt. The contracting volume law satisfactorily describes the data at higher degrees of decomposition. The maximum value ofa upto which the slow decomposition could be recorded was 0.75. The aged form of zinc hydroxy azide decomposes with much lower rates and slightly different topochemical characteristics. The decrease in the rate of decomposition on ageing has been attributed to the formation of carbonate on the surface of the compound during storage. The change in topochemical behaviour is traced to the reported layer structure of zinc hydroxy azide. The effect of pre-heating on subsequent thermal decomposition has also been discussed.     

Thermal decomposition of rare-earth trioxalatocobaltates

The thermal decomposition of rare-earth trioxalatocobaltates LnCo(C₂O₄)₃ · x H₂O, where Ln  La, Pr, Nd, has been studied in flowing atmospheres of air/oxygen, argon/ nitrogen, carbon dioxide and a vacuum. The compounds decompose through three major steps, viz. dehydration, decomposition of the oxalate to an intermediate carbonate, which further decomposes to yield rare-earth cobaltite as the final product. The formation of the final product is influenced by the surrounding gas atmosphere. Studies on the thermal decomposition of photodecomposed lanthanum trioxalatocobaltate and a mechanical mixture of lanthanum oxalate and cobalt oxalate in 1 : 2 molar ratio reveal that the decomposition behaviour of the two samples is different. The drawbacks of the decomposition scheme proposed earlier have been pointed out, and logical schemes based on results obtained by TG, DTA, DTG, supplemented by various physico-chemical techniques such as gas and chemical analyses, IR and mass spectroscopy, surface area and magnetic susceptibility measurements and X-ray powder diffraction methods, have been proposed for the decomposition in air of rare-earth trioxalatocobaltates as well as for the photoreduced lanthanum salt and a mechanical mixture of lanthanum and cobalt oxalates.     

Thermal decomposition of ammonium fluoroferrates (NH4)xFeF2x (2≤x≤3)

Different ammonium fluoroferrates (NH₄)_xFeF_2x (2≤x≤3) have been investigated. The thermal decomposition of the compounds obtained can be interpreted by their identical crystal structures (cryolite type). The decomposition products of all ammonium fluoroferrates formed in initial stage are isostructural of NH₄FeF₄. The decomposition is accompanied by the partial reduction of Fe(III) to Fe(II) by ammonium isolated. The end product of the thermal decomposition is FeF₂ and FeF₃ mixture.     

Solid phase decomposition of ammonium uranate

The thermal decomposition of ammonium uranate in air has been studied using TG, DTG, surface area measurements, chemical and X-ray analyses. The effect of washing and calcination at different temperatures is discussed. The optimum conditions for preparing β-UO₃ are chosen to be via ammonium uranate washed by distilled water and calcined at 500°C.The kinetics of the thermal decomposition are studied using Kissinger's shape index method. The thermal decomposition includes dehydration reaction, complicated reactions to form UO₃ and thermal decomposition of UO₃ to U₃O₈. The order of reaction is calculated for each stage.     

Correlation Between the Surface Acid-base Nature of Solid Metal Oxides and Temperature of CaSO4 Decomposition

By means of the combined use of scanning electron microscopy+energy dispersive spectrometry(SEM+EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetry (TG), the thermal decomposition of gypsum and gypsum bonded investment used for casting jewellery products has been studied in order to gain a further insight into the origin of the gas porosity in gold-based alloys produced via lost wax casting. The occurrence of the defect is related to the thermal decomposition of CaSO₄ that constitutes with silica the investment material and the decomposition of which takes place at a temperature very close to the casting temperature of some typical gold alloys. The decrease of the thermal decomposition temperature of gypsum is induced by the presence of silica and is related to the surface acid-base interaction between SiO₂ and CaSO₄. On the base of these results, the solid state thermal decomposition of calcium sulphate in the presence of other metal oxides characterised by different acid-base nature has been investigated and a correlation between the surface acid-base properties measured as isoelectric point of the solid surface (IEPS) and via XPS analysis and the temperature of CaSO₄ thermal decomposition is observed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermoanalytical studies of silver and lead jarosites and their solid solutions

Dynamic and controlled rate thermal analysis has been used to characterise synthesised jarosites of formula [M(Fe)₃(SO₄)₂(OH)₆] where M is Pb, Ag or Pb–Ag mixtures. Thermal decomposition occurs in a series of steps. (a) dehydration, (b) well defined dehydroxylation and (c) desulphation. CRTA offers a better resolution and a more detailed interpretation of water formation processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of water formation reveal the subtle nature of dehydration and dehydroxylation. CRTA offers a better resolution and a more detailed interpretation of the decomposition processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of non-isothermal nature reveal separation of the dehydroxylation steps, since in these cases a higher energy (higher temperature) is needed to drive out gaseous decomposition products through a decreasing space at a constant, pre-set rate.