Phase equilibria in the system NiO-V2O5-Fe2O3 in subsolidus area

Reactivity of FeVO₄ towards Ni₂V₂O₇ and Ni₃V₂O₈ in the solid state was investigated. On the base of XRD and DTA results, phase diagrams in subsolidus area of the FeVO₄-Ni₂V₂O₇ and FeVO₄-Ni₃V₂O₈ intersections of the ternary system NiO-V₂O₅-Fe₂O₃ have been worked out and the phase diagram of this ternary system in subsolidus area in the whole component concentration range has been verified. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characterization and assessment of Saudi clays raw material at different area

The general characteristics of three types of clays obtained from the different locations in Saudi Arabia have been investigated. These clays were compared with those of pure kaolin samples. Clays were analyzed by DTA, TGA, SEM, X-ray diffraction, chemical composition (XRF) and optical properties. Three clays are white clay (WC), red clay (RC) from Jeddah area and grey clay (GC) from Elmadina area. The comparison made with Spain clay as pure kaoline (KA). The clays contain kaolinite, illite, montmorillonite and quartz. Quartz is present in every class and varies between 45% and 20%. Montmorillonite is found mainly in the WC (50%) and are lacking only in sample RC and GC. Another important aspect with respect to the chemical composition of the clays is the low amounts of Na₂O and K₂O. The clay deposits (WC, RC, and GC) are suitable for use in industrial ceramics due to the low whiteness, high yellowness and high content of impurities as montmorillonite and iron. This is an important technological aspect that renders possible use of clay RC and GC in the fabrication of products with a cream tonality, especially in roofing tiles and rustic floor tiles. The results also, showed that the studied clays have adequate characteristics for ceramics wall, floor, roof tiles, tableware, earthenware and brick fabrication.     

Investigation of synthesis and microstructure of bismuth titanates with TiO<Subscript>2</Subscript> rich compositions

Preliminary examinations regarding formation of bismuth titanates in a part of Bi₂O₃—TiO₂ system rich with TiO₂ have been carried out. Bismuth titanates have been synthesized from mixtures of Bi₂O₃ and TiO₂ (anatase) by the conventional solid-state method at the temperatures ranged from 1273 to 1473 K. Differential thermal analysis (DTA), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) have been used to study the formation of bismuth titanates. The following compounds have been achieved: Bi₄Ti₃O₁₂, Bi₂Ti₂O₇ and Bi₂Ti₄O₁₁. Existence of controversial bismuth titanate of formula Bi₂Ti₃O₉ in the Bi₂O₃—TiO₂ system has not been confirmed.     

Phase relations in subsolidus area of ZnO-V2O5-Fe2O3 system

Phase equilibria in subsolidus area in the ZnO-V₂O₅-Fe₂O₃ system have been investigated over the whole concentration range of the oxides. The components of this system form two compounds: Zn₂FeV₃O₁₁ and Zn₃Fe₄(VO₄)₆. A solidus area projection onto the component concentration triangle plane of the ZnO-V₂O₅-Fe₂O₃ system has been constructed using DTA and XRD methods. 11 subsidiary subsystems can be distinguished in this system. Melting temperatures of mixtures of solid phases coexisting at equilibrium in each of subsidiary subsystems were determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal solid–solid interactions and physicochemical properties of NiO/Fe2O3 system doped with K2O

The effects of calcination temperature and doping with K₂O on solid–solid interactions and physicochemical properties of NiO/Fe₂O₃ system were investigated using TG, DTA and XRD techniques. The amounts of potassium, expressed as mol% K₂O were 0.62, 1.23, 2.44 and 4.26. The pure and variously doped mixed solids were thermally treated at 300, 500, 750, 900 and 1000 °C. The catalytic activity was determined for each solid in H₂O₂ decomposition reaction at 30–50 °C. The results obtained showed that the doping process much affected the degree of crystallinity of both NiO and Fe₂O₃ phases detected for all solids calcined at 300 and 500 °C. Fe₂O₃ interacted readily with NiO at temperature starting from 700 °C producing crystalline NiFe₂O₄ phase. The degree of reaction propagation increased with increasing calcination temperature. The completion of this reaction required a prolonged heating at temperature >900 °C. K₂O-doping stimulates the ferrite formation to an extent proportional to its amount added. The stimulation effect of potassium was evidenced by following up the change in the peak height of certain diffraction lines characteristic NiO, Fe₂O₃, NiFe₂O₄ phases located at “d” spacing 2.08, 2.69 and 2.95 Å, respectively. The change of peak height of the diffraction lines at 2.95 Å as a function of firing temperature of pure and doped mixed solids enabled the calculation of the activation energy (ΔE) of the ferrite formation. The computed ΔE values were 120, 80, 49, 36 and 25 kJ mol⁻¹ for pure and variously doped solids, respectively. The decrease in ΔE value of NiFe₂O₄ formation as a function of dopant added was not only attributed to an effective increase in the mobility of reacting cations but also to the formation of potassium ferrite. The calcination temperature and doping with K₂O much affected the catalytic activity of the system under investigation.     

Synthesis and selected properties of Co3Fe4V6O24

A new compound Co₃Fe₄V₆O₂₄ has been obtained by solid state reaction. Temperature of its incongruent melting amounts to 890±5°C. Results of indexing the powder diffraction pattern and unit cell parameters of Co₃Fe₄V₆O₂₄ are also given. This compound is probably isostructural with M₃Fe₄V6O₂₄ (where M = Zn, Mg, Mn). IR spectrum of Co₃Fe₄V₆O₂₄ phase is presented. This revised version was published online in July 2006 with corrections to the Cover Date.     

原位XRD反应装置下H2O对Fe5 C2的物相及F-T反应性能影响的研究

将原位XRD反应装置与在线气相色谱技术结合,研究了不同H_2O含量(4.36%、1.68%、0.56%)条件下单一相Fe_5C_2的氧化速率,并考察了不同Fe_5C_2氧化程度(0、25%、55%、68%)和氧化次数对其费托合成(F-T)反应性能的影响。研究结果表明,Fe_5C_2物相的氧化速率随H_2O含量的提高而逐渐增加,同时H_2O氧化使Fe_5C_2颗粒粒径减小,暴露出更多活性位点,造成F-T反应活性提高,且氧化程度越大,活性提高越明显;随着氧化次数的增加,F-T反应活性逐渐提高,但CH_4选择性增加,C_(5+)选择性逐渐降低。     

Synthesis,characterization, and morphology of p‐toluene sulfonic acid‐doped polyaniline: A material for humidity sensing application

Polyaniline (PANI) doped with p‐toluene sulfonic acid was synthesized by chemical polymerization method using (NH₄)₂S₂O₈ as an oxidizing agent. This is a single step polymerization process for the direct synthesis of the conducting emeraldine salt (ES) phase, without the need of doping, dedoping, and redoping of the polymer. Presence of a free carrier tail at higher wavelength, characteristic of extended coil conformation along with a sharp polaronic peak is observed in the UV–vis spectrum of doped PANI in m‐cresol solvent. FT‐IR studies show the characteristic peaks of ES phase along with a sharp peak at 1120 cm^?1 representing vibration band of the dopant ion. Clumps of small fibers resulting in a sponge‐like structure was observed under scanning electron microscope. Thermal studies revealed a three‐step decomposition pattern. Conductivity is found to increase with an increase in the temperature showing “thermal activation behavior.” Decrease in resistance with increasing humidity is observed in a broad range of humidity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2161–2169, 2005     

Growth morphology and properties of metals on graphene

Graphene, a single atomic layer of graphite, has been the focus of recent intensive studies due to its novel electronic and structural properties. Metals grown on graphene also have been of interest because of their potential use as metal contacts in graphene devices, for spintronics applications, and for catalysis. All of these applications require good understanding and control of the metal growth morphology, which in part reflects the strength of the metal–graphene bond. Also of importance is whether the interaction between graphene and metal is sufficiently strong to modify the electronic structure of graphene. In this review, we will discuss recent experimental and computational studies related to deposition of metals on graphene supported on various substrates (SiC, SiO₂, and hexagonal close-packed metal surfaces). Of specific interest are the metal–graphene interactions (adsorption energies and diffusion barriers of metal adatoms), and the crystal structures and thermal stability of the metal nanoclusters.     

Synthesis and characterization of some methylbismuth (III) O,O‐alkylenedithiophosphates: convenient transformation of and to pure Bi2S3

A series of methylbismuth(III)O,O‐alkylenedithiophosphates of the type [where G = CH₂CH(CH₃) ( 1 ), (CH₂)₄ ( 2 ), CH₂CH₂CH(CH₃) ( 3 ), CH(CH₃)CH(CH₃) ( 4 ), CH₂CHCH₂CH₃ ( 5 ), CH(CH₃)CH₂C(CH₃)₂ ( 6 ) and C(CH₃)₂C(CH₃)₂ ( 7 )] have been isolated by the reaction of methylbismuth(III) dichloride with potassium salt of O,O‐alkylenedithiophosphoric acids in 1:2 molar ratio in anhydrous benzene. These newly synthesized derivatives were characterized by elemental analyses, FT IR and multinuclear NMR (¹H, ¹³C and ³¹P) spectral studies. Thermogravimetric analysis of 6 has shown a single‐step decomposition of complex to Bi₂S₃ at 154.3 °C. Transformation of 2 and 6 to pure Bi₂S₃ was carried out successfully at refluxing xylene temperature (142 °C) as revealed by XRD and SEM analyses. Copyright © 2006 John Wiley & Sons, Ltd.     

New polymeric based materials: terpoly(aniline,diphenyl amine,and o‐anthranilic acid) / kaolinite composites

Terpolymers of aniline, diphenyl amine and o‐anthranilic acid (PANIDPAA) / kaolinite clay composites were synthesized by 1:1:1 molar ratios of the respective monomers with different percentages of kaolinite clay particles via in situ chemical terpolymerization. The spectral characteristics upon incorporation of o‐anthranilic acid and diphenyl amine units into the polyaniline backbone in presence of kaolinite clay were investigated. The results were justified by measuring the UV–Vis absorption spectra, FT‐IR for PANIDPAA emeraldine base (EB), and PANIDPAA EB / kaolinite clay composite. Also, the thermal gravimetric analyses for the isolated terpolymer powder in the bulk in absence and in presence of kaolinite clay were carried out. Moreover, the morphology of the polymer clay composites system was studied by the scanning electron microscope micrographs at different magnifications. X‐ray diffraction was used to measure the nature of polymer and extent of crystallinity present in the neat terpolymer and terpolymer / kaolinite composite materials. Copyright © 2016 John Wiley & Sons, Ltd.     

Na_5P_3O_(10)-Ca(OH)_2-CO_2-H_2O体系纳米CaCO_3的成核与生长

通过化学分析、SEM显微分析技术结合RosinRamiler概率统计理论从介观层次研究Na5P3O10CaOH2CO2H2O体系纳米CaCO3的合成反应及其成核和生长过程。结果表明Na5P3O10对CaOH2的碳化反应具有抑制作用。随着Na5P3O10的增加体系中CaCO3的成核速率B0逐渐增大。在Na5P3O10=0ppm时CaCO3结晶的生长由长程扩散和凝聚生长控制Na5P3O10=380.4760.9ppm时前期受短程扩散和界面反应控制、后期受长程扩散控制。Na5P3O10的存在抑制了纳米CaCO3的晶体生长。     

Synthesis and properties of a solid solution formed in the CrVMoO7 - AlVMoO7 system

It has been shown by the methods of X-ray powder diffraction (XRD), differential thermal analysis (DTA) and infrared spectroscopy (IR) that solid solutions of a formula Cr_1−xAl_xVMoO₇, where xε (0−0.65), are formed in the system CrVMoO₇-AlVMoO₇. The obtained research results have proven that the ions Al3+ are incorporated into the crystal lattice of CrVMoO₇ instead of Cr³⁺, which causes a contraction of the lattice and a shift of IR absorption bands towards higher values of wavenumbers. The phases Cr_1−xAl_xVMoO₇ melt incongruently in the temperature range from 710°C (for x=0.65) to ∼820°C in the case of x close to zero This revised version was published online in July 2006 with corrections to the Cover Date.     

不同形貌ZSM-5分子筛的制备及其催化甲醇转化制烯烃性能

采用廉价的原料,通过添加尿素及调节碱度,在水热条件下合成了具有不同形貌的ZSM-5分子筛。研究了分子筛形貌对甲醇转化制丙烯催化性能的影响。结果表明,通过控制尿素含量及碱度,可以对ZSM-5分子筛晶体的生长方向及形貌进行调控。当urea/SiO₂(mol ratio)=0.28,Na₂O/SiO₂(mol ratio)=0.035时,所得到的分子筛沿b轴方向生长最慢,产品形貌呈薄片状,厚度为130 nm;在一定范围内提高碱度,会使分子筛形貌逐渐变为纳米颗粒聚集体。ICP、NH₃-TPD和N₂吸附表征结果表明,所合成的分子筛SiO₂/Al₂O₃物质的量比、酸性质及孔道性质接近。催化反应评价结果表明,薄片状样品HZ-1由于在b轴方向上具有更短的扩散路径,且结晶度高,在催化甲醇转化反应中不仅表现出良好的选择性,双烯(乙烯+丙烯)收率可达60%以上;P/E比(丙烯/乙烯)最高可达8.4,在连续反应200 h后,甲醇转化率仍保持在95%以上,表现出优异的催化稳定性。     

添加磷、硼、硅和铝的锂离子电池材料LiNiO2研究

研究了添加元素磷，硼硅和铝对锂离子蓄电池材料LiNiO2的影响。添加磷，硼、硅和铝的目的是提高LiNiO2的放电平台和充放电稳定性，增加循环寿命并且提高充放电能量，在n(LiOH):n(Ni(OH)2)为1.1:1.0的材料中分别加入P2O5;H3BO3,SiO2,Al2O3，保持4种元素与锂的摩尔比值分别为0.01,0.02,0.03,0.04和0.05，分析测定了样品的充放电曲线和循环伏安曲线，并采用XRD对样品的放电过程和合成产品进行了结构分析，结果证明，当n(P)/n(Ni)=0.02,n(B)/n(Ni)=0.03,n(Si)/n(Ni)\0.02,n(Al)/n(Ni)=0.02时，LiNiO2的放电电压提高，添加元素使LiNiO2在充放电过程中的晶型转变过程发生改变，使六方晶系向单斜晶系转变的趋势变小，这将改善LiNiO2的循环性能，但没有影响锂离子的嵌入和脱嵌机理，XRD分析表明，添加磷和铝使LiNiO2的层状结构更完善，同时增加了活性，但添加硼和硅以后，LiNiO2的XRD图上的衍射峰（003）强度度减弱，衍射峰（018）和（019）峰也有改变，这证明B和Si影响了LiNiO2性能。     

Cu2O nanocrystals with various morphology: Synthesis,characterization and catalytic properties

Cu₂O nanocubes, octahedra, spheres and truncated rhombic dodecahedral were prepared and their structural, morphological, and electronic properties were investigated by X-ray diffraction analysis, X-ray absorption near edge structure, scanning electron microscope and transmission electron microscope and X-ray absorption near edge structure. Cu₂O nanocrystals were successfully employed to catalyze the 1,3-dipolar cycloaddition reaction for the synthesis of 1,4-disubstituted triazoles. Cu₂O nanocubes and octahedral showed the superior catalytic performance in the cycloaddition reaction. These results reveal that crystal-plane engineering of oxide catalysts is a useful strategy for developing efficient catalysts for organic reaction.     

N，N’-双间甲苯基-3，6-二甲基-1，4-二氢-s-四嗪-1，4-二甲酰胺的合成和晶体结构

间甲苯基异氰酸酯与3，6-二甲基-1，6-二氢-s-四嗪反应生成标题化合物 (C20H22N6O2，Mt＝378．44)．经X射线单晶结构分析表明，此晶体属正交晶系， P212121空间群，晶胞参数分别为：α=1．1602(2)nm，b=1．5921(3)nm，c=1． 3918(3)nm，V＝1．9874(10)nm^3，Z=4，Dc＝1．265g／cm^3，μ(MoKα)＝0． 086mm^-1,F(000)=800,R和ωB分别是0.0619和0．1495．结果表明该化合物的两个 酰胺基接在s-四嗪环的1，4-位，而四嗪环呈船式构象，不具有同芳香性，分子中 存在氢键．     

5-Anthracenylidene and 5-(4-Benzyloxy-3-methoxy)benzylidene-hydantoin and 2-Thiohydantoin Derivatives,Synthesis, and S-Alkylation

Abstract

5-Anthracenylidene- and 5-(4-benzyloxy-3-methoxy)benzylidene-hydantoin and 2-thiohydantoin derivatives 3a-g were prepared by condensation of anthracene-9-carboxaldehyde and 4-benzyloxy-3-methoxybenzylaldehyde with hydantoin and 2-thiohydantoin derivatives. Compounds 3a, b, f undergo Mannich reaction with formaldehyde and morpholine to give the corresponding Mannich products 4a–c. For the synthesis of alkylmercaptohydantoin 5a–o, the potassium salt of compounds 3a, b, e, f were reacted with an alkylhalide, either methyl iodide, phenacyl bromide, ethyl bromo acetate, allyl bromide, or methallyl bromide, under stirring at room temperature to afford the alkylmercaptohydantoins 5a–o. Acid hydrolysis of compounds 5a–c afforded the corresponding arylidene-hydantoin derivatives 3c, d, g. 2-Methylmercapto-hydantoin derivatives 5a, c were reacted with some secondary amines such as morpholine or piperidine to afford 5-(4-benzyloxy-3-methoxy)benzylidene-2-morpholino- or piperidino glycocyamidine derivatives 7a, 5-anthracenylidene-2-morpholin-, or piperidino glycocyamidine derivatives 7b, c.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT     

Preparation and Some Properties of Lithium Vanadium Bronzes

Lithium vanadium bronzes with composition formula Li_xV₂O₅ (0.04 ≤ × ≤ 0.92) have been prepared by solid‐state reaction at 650 °C in argon atmosphere. The obtained products were characterized by X‐ray powder diffraction and IR spectroscopy. The results reveal that four phases are present in the range from x = 0.04 to 0.92, namely α, β, β′, and γ phase. The magnetic susceptibility for the investigated bronzes was measured using the conventional Gouy's method. The values of the effective magnetic moments, as calculated from experimental data, indicate the presence of V⁴⁺ ions in all bronze samples. The electrical conductivity as a function of temperature and lithium content was measured in the temperature range from room temperature to 483 K. The electrical conductivity of the bronzes is found to be affected by lithium content. The values of the electrical conductivity increase with temperature for the prepared samples and both electronic and ionic conduction are discussed.