共查询到20条相似文献,搜索用时 31 毫秒
1.
Bán Margit Madarász J. Bombicz Petra Pokol G. Gál S. 《Journal of Thermal Analysis and Calorimetry》2004,78(2):545-555
Composition and structure of crystals of unknown origin, crystallizing spontaneously from ethylenediamine on standing, has
been determined by elemental analysis, FTIR, 1H and 13C NMR spectroscopy and X-ray diffraction. The crystal with molecular formula C6H14N4 has been found to be a highly symmetric
saturated imino compound with double-ring structure, and unambiguously identified as trans-1,4,5,8-tetraazodecalin by 1H NMR and powder X-ray diffraction based on both its specific AA'BB' spin coupling system and simulated XRD pattern calculated
from available data of previous single crystal structure determination, respectively. Simultaneous TG/DTA measurement shows
one-step degradation of this compound. The volatile decomposition products have been followed by both TG/DTA-MS and TG-FTIR.
Group of the largest fragments (m/z=80, 81 and 82) observed by TG/DTA-MS corresponds to an aromatic 1,4-diazine (pyrazine). In the EGA-FTIR spectrum of released
gaseous species measured at the highest evolution rate by TG-FTIR, ethylenediamine can be identified as another decomposition
product.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Non-stoichiometric zirconium oxide nanocrystals with the formula of ZrO2.12 and diameters less than 10 nm were synthesized in the course of calcination of a dried solution of zirconium(IV) oxy nitrate in the presence of citric acid at 600 °C for 5 h. Crystallite size of product was increased to 20 nm when starch was used as emulsifier. Effect of the organic additive, which was equal of moles of the nitrate ions of the zirconium precursor, was investigated on phase formation, morphology and particle size of products. Samples were characterized by FT-IR, TG/DTA, SEM and TEM analysis. Phase structure of samples were also analysed by the powder X-ray diffraction. 相似文献
3.
S. P. Khranenko A. V. Alexeyev D. Yu. Naumov P. E. Plusnin S. A. Gromilov 《Journal of Structural Chemistry》2012,53(4):748-752
The crystal structure of [Co(NH3)6](WO4)Cl complex salt is determined by single crystal X-ray. The thermal properties are examined, and the products obtained on heating the salt in different gaseous atmospheres are analyzed by powder X-ray diffraction. 相似文献
4.
D. Ramarajan 《Journal of solid state chemistry》2011,184(3):597-600
Cubic and chain-like structure of α-Mn2O3 with a high surface area was prepared by air oxidation of manganese chloride through sol process by adding hexamine and mercaptosuccinic acid as wetting agent, respectively. The as-synthesized products were characterized with X-ray powder diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), and selected area electron diffraction (SAED). The possible formation mechanism of α-Mn2O3 cubic and chain-like nanostructures has been proposed and discussed. 相似文献
5.
M. E. Matthews I. Atkinson Lubaina Presswala O. Najjar Nadine Gerhardstein R. Wei Elizabeth Rye A. T. Riga 《Journal of Thermal Analysis and Calorimetry》2008,93(1):281-287
Dielectric analysis (DEA), supported by thermogravimetric analysis (TG), differential scanning calorimetry (DSC), powder X-ray
diffraction analysis (PXRD) and photomicrography, reveal the chiral difference in the amino acids. The acids are classified
as dielectric materials based on their structure, relating chirality to the vector sum of the average dipole moment, composed
of the constant optical (electronic) and infra-red (atomic) polarizabilities, as well as dipole orientation. This study encompasses
14 L-and D-amino acid isomers. Physical properties recorded include AC electrical conductivity, charge transfer complexes, melting,
recrystallization, amorphous and crystalline phases, and relaxation spectra, activation energies and polarization times for
the electrical charging process. 相似文献
6.
以钛酸正丁醇和乙二醇为原料,采用溶剂热法合成了钛乙二醇盐(TG)前躯体,在高压汞灯照射下制备出无定形TiO2。利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)、紫外-可见吸收光谱(UV-Vis)、表面光电压谱(SPS)、N2吸附-脱附对所得材料进行了结构和性能的表征。借助X射线吸收精细结构(XAFS)对无定形TiO2的形成机制进行了分析,并通过硝基苯的还原反应考察了材料的光催化性能。结果表明:在紫外光驱动无定形TiO2的形成过程中,中心元素Ti4+的配位环境发生变化,由八面体结构转变为四面体结构;由于特殊的孔道结构使得多孔无定形TiO2显示出较好的光催化活性。 相似文献
7.
Kirill A. Kovnir Yury V. Kolen’ko Sugata Ray Tomoaki Watanabe Masahiro Yoshimura 《Journal of solid state chemistry》2006,179(12):3756-3762
An effective method of synthesis of tin phosphide Sn4P3 starting from metallic tin and amorphous red phosphorus by a low-temperature (200 °C) solvothermal reaction in ethylenediamine is offered. The key parameters of this process - duration, temperature, and the ratio of initial components (Sn/P) are studied. The structure, phase composition, and morphology of the products are investigated using powder X-ray diffraction and scanning electron microscopy. Different synthetic ways for tin phosphide are discussed and compared with the proposed one. The mechanism of solvothermal preparation of tin phosphide in ethylenediamine is discussed. It is shown that the proposed solvothermal method opens up the possibility of preparing other metal-rich phosphides. 相似文献
8.
Tosic acid on silica gel (TsOH-SiO2) was synthesized and characterized using microscopic and spectroscopic techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Thermal behaviour of the catalyst was investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. TsOH-SiO2 showed excellent catalytic activity for the Knoevenagel condensation and was recyclable for six cycles. 相似文献
9.
10.
Irma Bogdanoviciene Kaia T?nsuaadu Valdek Mikli Inga Grigoraviciute-Puroniene Aldona Beganskiene Aivaras Kareiva 《Central European Journal of Chemistry》2010,8(6):1323-1330
Aqueous sol-gel chemistry routes — based on ammonium hydrogen phosphate as the phosphorus precursor, calcium acetate monohydrate
as the source of calcium ions, and 1,2-diaminocyclohexanetetraacetic acid monohydrate (DCTA) as the complexing agent — have
been used to prepare calcium hydroxyapatite (HA). The sol-gel process was performed in aqueous solution at different pH values
followed by calcination of the dry precursor gels for 5 h at 1000°C. Phase transformations, composition, and structural changes
in the polycrystalline samples were studied by thermoanalytical methods (TG/DTA), infrared spectroscopy (IR), X-ray powder
diffraction analysis (XRD), and scanning electron microscopy (SEM). It was shown that pH adjustment has significant impact
on the apatite formation process and on the morphology and phase purity of the ceramic samples. 相似文献
11.
Šubrt J. Balek V. Criado J. M. Pérez-Maqueda L. A. Večerníková Eva 《Journal of Thermal Analysis and Calorimetry》1998,53(2):509-517
Effects induced by grinding in synthetic goethite samples were studied. The products of α-FeOOH grinding were characterised
by means of DTA, TG/DTG coupled with EGA (Mass spectrometry detection), powder X-ray diffraction analysis, and surface area
determination.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Helen Merina Albert A. Joseph Arul Pragasam G. Bhagavannarayana C. Alosious Gonsago 《Journal of Thermal Analysis and Calorimetry》2014,118(1):333-338
l-histidinium glutarate monohydrate, an organic nonlinear optical crystal has been successfully grown from deionized water by slow solvent evaporation method at room temperature. Crystal structure and its lattice parameters were identified by single-crystal X-ray diffraction technique. Crystalline perfection of the grown crystal was studied by high-resolution X-ray diffraction rocking curve measurements by employing a multicrystal X-ray diffractometer. FT-IR and FT-Raman spectral studies were employed to identify the presence of various functional groups and mode of vibrations in the crystal. Thermal behavior of the crystal was studied by TG–DTA, TG–DTG, and DSC analyses. Optical absorption of the crystal in the wavelength region 200–1,000 nm was studied by UV–Vis–NIR spectral analysis. Kurtz and Perry powder technique was employed to find the second harmonic generation efficiency of the crystal. 相似文献
13.
The products of reaction of natural chrysotile fibers with phenylarsonic acid or 2-nitrophenol-4-arsonic acid are described. The new grafted layered materials with basal spacing of 15.5 and 17.0 A were characterized by powder X-ray diffraction, thermal analysis, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The experimental data are consistent with the grafting of phenylarsonate and 2-nitrophenol-4-arsonate groups onto the surface of the disordered silica, obtained by the in situ acidic leaching of the brucite-like sheets starting from the original chrysotile structure. 相似文献
14.
The Pb(IO3)2 crystals have been grown in sodium meta silicate gel using the single diffusion method at room temperature. The grown crystals
were characterized by thermo analytical techniques (TG, DTA, and DTG), X-ray powder diffraction (XRD), and FTIR spectroscopy.
The crystal system is confirmed to be orthorhombic having lattice parameters a = 6.09 Å, b = 16.68 Å, and c = 5.58 Å by powder
X-ray diffraction analysis. FTIR study reveals that lead iodate crystal is anhydrous. TG, DTA, and DTG analysis shows a remarkable
thermal stability. 相似文献
15.
Lanthanum(III) tris-tartrato lanthanate(III) decahydrate, La[La(C4H4O6)3]·10H2O has been synthesized and characterized by elemental analysis, IR, electronic spectral and X-ray powder diffraction studies.
Thermal studies (TG, DTG and DTA) in air showed a complex decomposition pattern with the generation of an anhydrous species
at ~170°C. The end product was found to be mainly a mixture of La2O3 and carbides at ~970°C through the formation of several intermediates at different temperature. The residual product in DSC
study in nitrogen at 670°C is assumed to be a similar mixture generated at 500°C in TG in air. Kinetic parameters, such as,
E*, ΔH, ΔS, etc. obtained from DSC are discussed. IR and X-ray powder diffraction studies identified some of the decomposition products.
The tentative mechanism for the thermal decomposition in air of the compound is proposed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
《Journal of Coordination Chemistry》2012,65(9):1578-1585
A new 3-D coordination polymer [Zn(L)2] (1) (HL?=?4-(pyridin-4-ylmethoxy)benzolic acid) was synthesized under hydrothermal conditions with Zn(OAc)2?·?2H2O and HL and characterized by single crystal X-ray diffraction (XRD). Compound 1 displays a 3-D 8-fold interpenetrating structure with diamondoid framework containing large adamantanoid cages. Meanwhile, it exhibits intense fluorescence at 402?nm in the solid state. In addition, powder XRD and thermogravimetric (TG) analysis for 1 are also reported. 相似文献
17.
ABSTRACT The radiation-induced solid-state polymerization of acenaphthylene was carried out under vacuum at room temperature. The monomer and obtained polymer samples were investigated by UV, FTIR, DSC, TG, and powder X-ray diffraction methods to characterize the polymer and elucidate the polymerization mechanism. The polymer samples were crystalline with melting points ranging in 380-390°C interval. Polymerization takes place through vinyl groups by a radical mechanism and crystal structure of monomer and polymer studied by powder X-ray diffraction were quite similar. The space group for both were P22 1 2 and cell parameters: a = 784.2 (6), b = 798.1(6), c = 1417.0(1) pm for monomer, and a = 791.7(8), b = 803.8(7), c =1431.0(1) pm for polymer. The similarity of crystal structures shows a topotactic polymerization of monomer. 相似文献
18.
Y. Q. Xu X. F. Wang J. W. Ji Z. B. Han 《Russian Journal of Coordination Chemistry》2011,37(10):748-751
A new coordination polymer (H3O+)[In(Tbip)2] · H2O (I) (H2Tbip is 5-tert-butylisophthalic acid) has been synthesized under hydrothermal conditions. Complex I has been characterized by elemental analysis, IR, TG analysis, and powder X-ray diffraction. Single-crystal X-ray diffraction
studies revealed that I crystallizes in the monoclinic crystal system, space group C2/c. In I the metal centers are linked by bridging Tbip ligand to form an interesting extended two-dimensional rhombic network. 相似文献
19.
Frederick L. Theiss Sara J. Palmer Godwin A. Ayoko Ray L. Frost 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1123-1128
The removal of the sulfate anion from water using synthetic hydrotalcite (Mg/Al LDH) was investigated using powder X-ray diffraction
(XRD) and thermogravimetric analysis (TG). Synthetic hydrotalcite Mg6Al2(OH)16(CO3)·4H2O was prepared by the co-precipitation method from aluminum and magnesium chloride salts. The synthetic hydrotalcite was thermally
activated to a maximum temperature of 380 °C. Samples of thermally activated hydrotalcite where then treated with aliquots
of 1000 ppm sulfate solution. The resulting products where dried and characterized by XRD and TG. Powder XRD revealed that
hydrotalcite had been successfully prepared and that the product obtained after treatment with sulfate solution also conformed
well to the reference pattern of hydrotalcite. The d(003) spacing of all samples was found to be within the acceptable region for a LDH structure. TG revealed all products underwent
a similar decomposition to that of hydrotalcite. It was possible to propose a reasonable mechanism for the thermal decomposition
of a sulfate containing Mg/Al LDH. The similarities in the results may indicate that the reformed hydrotalcite may contain
carbonate anion as well as sulfate. Further investigation is required to confirm this. 相似文献
20.
A mixed metal carboxylate, cadmium(II)bis(oxalato)cobaltate(II)pentahydrate, has been synthesized and characterized by elemental
analysis, IR spectral, reflectance and X-ray powder diffraction studies. Thermal decomposition studies (TG, DTG and DTA) in
air showed that the compound decomposed to CdCoO3 at 370°C through the formation of an anhydrous compound at ~194°C. Finally,
CdCoO2 is generated at 1000°C. DSC study in nitrogen up to 550°C showed the formation of a mixture of CdO and Co3O4 as end products. The kinetic parameters have been evaluated for the dehydration and decomposition steps using four non-mechanistic
equations, i.e., Freeman and Carroll, Coats and Redfern, Flynn and Wall, MacCallum and Tanner equations. Using seven mechanistic
equations, the rate controlling processes of the dehydration and decomposition mechanism are also inferred. The kinetic parameters,
DH and DS obtained from DSC are discussed. IR and X-ray powder diffraction studies identified some of the decomposition products. A
tentative mechanism for the decomposition in air is proposed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献