ChemInform Abstract: Synthesis of Titanium Silicon Carbide.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Adsorption Isotherm Studies on Titanium Carbide Powders

We have used adsorption isotherms to perform a comparative study of the substrate quality of five groups of titanium carbide powder, manufactured following different procedures. The isotherms were measured in an automated setup at 77.3 K using methane and argon as the adsorbates. We determined the specific surface area of each of the powders studied. We also determined whether or not there was evidence of steps (indicative of layer-by-layer adsorption) in each set of adsorption data. The isothermal compressibilities of the adsorbed films were determined from the data measured for each sample. Adsorption measurements were also conducted to determine the effect that heating the powders under vacuum had on the resulting substrate quality.     

d-Xylose-based surfactants: Synthesis,characterization and molecular modeling studies

Pentose-derived surfactants were easily synthesized and fully characterized through classical analytical methods. The interfacial behaviors revealed the importance of both the length of the hydrophobic chain and the nature of the anomeric form. Finally, the spatial conformation of four xylosides was obtained by molecular modeling with software Hyperchem^® 4 using the semi-empirical method PM3, which demonstrated the role of hydrophobic interactions in the stability of the compounds.     

ZnS微米花的水热合成及光催化性质研究

本文采用简便的水热法一步合成ZnS微米花,通过X射线衍射仪、扫描电子显微镜等表征手段研究了合成产物的形貌及微观结构,并考察了合成产物的光催化性质。合成产物的光催化测试结果表明,在紫外光辐照下,产物对亚甲基蓝、甲基橙和曙红都有很好的降解效果。为了测试产物循环利用的光催化能力,对其进行了5次降解实验,结果显示产物依然保持良好的光催化活性。     

ChemInform Abstract: New Zirconium Titanium Oxynitrides Obtained by Ammonolysis of Zirconium Titanate.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

改性硫酸钛催化合成丙酸酯

固体硫酸钛经不同的高温灼烧制得改性硫酸钛，用改性硫酸钛吸附吡啶后的IR光谱表征其表面酸性；用丙酸与多种醇反应考察其酯化催化活性。结果表明，改性硫酸钛表面存在明显的Broensted酸中心；对酯化反应的催化活性高、反应时间短、催化剂可重复使用多次。     

Synthesis of Hollow Gold Nanospheres and Their Applications in Surface-enhanced Raman Scattering and DNA Biosensor

Hollow gold nanospheres (HGNs) with nanopinholes were prepared by chemical reduction of HAuCl₄ with aqueous KBH₄ in the presence of the Bu₄PBr template. The HGNs could be served as substrates for surface‐enhanced Raman scattering (SERS), which exhibited much higher surface enhancement than the solid gold nanoparticles in case of Rhodamine 6G as a molecule probe. Moreover, the HGNs could also be used in the modified electrode to detect DNA and superior to the solid counterpart of the similar size. Based on the detailed characterizations by transmission electron micrograph (TEM), field emission scanning electron micrograph (FESEM) and UV‐visible absorption spectroscopy, a plausible mechanism for forming HGNs was proposed. Meanwhile, the promoting effect of the hollow gold nanospheres on the SERS was discussed briefly.     

Optically Active Sulfoxides and Low-Valent Titanium in Asymmetric Synthesis of Natural Products

The total synthesis of lasiodiplodin via optically active sulfoxides and the preparation of polyenes through low valent titanium reagents are described.     

分子印迹型二氧化钛及其复合材料的合成和应用

分子印迹技术是将分子设计、大分子合成、分子识别、生物模拟以及生物工程等技术的优点结合起来发展而成的一种新兴跨学科方法,所形成的分子印迹聚合物亲合性好、选择性和稳定性高。二氧化钛及其复合材料价格低廉、安全高效、绿色环保、光催化活性高,被广泛应用于光催化、光电转换等领域。二氧化钛及其复合材料形成的分子印迹聚合物稳定性高,光催化活性好,并且具有良好的选择性,能对低浓度、高毒性污染物进行选择性富集及光催化降解,拓宽了其应用范围。本文综述了近二十年来分子印迹型二氧化钛及其复合材料的制备方法及其在光催化降解、传感器构建以及其他领域的应用概况,并进行展望。     

低价钛在有机合成中的应用新进展

主要综述了近年来低价钛诱导的McMurry反应在有机合成中的应用新进展.     

Synthesis of CdTe Quantum Dots with Tunable Photoluminescence Using Tellurium Dioxide as Tellurium Source

A simple and convenient method has been developed for synthesis of water‐soluble CdTe quantum dots (QDs) under ambient atmospheric conditions. In contrast to the traditional aqueous synthesis, green to red emitting CdTe QDs were prepared by using TeO₂ to replace Te or Al₂Te₃ as tellurium source in this method. The influences of experimental variables, including pH value, 3‐mercaptopropionic acid (MPA)/Cd and Te/Cd molar ratios, on the emission peak and photoluminescence (PL) quantum yield (QY) of the obtained CdTe QDs have been systematically investigated. Experimental results indicate that green to red emitting CdTe QDs with a maximum photoluminescence quantum yield of 35.4% can be prepared at pH 11.3 and n_(Cd):n_(Te):n_(MPA)=1:0.1:1.7.     

Methodical Thermolysis of [Ba2Ti2(thd)4(OnPr)8(nPrOH)2] under Autogenous Pressure Followed by Combustion for the Synthesis of Dielectric Tetragonal BaTiO3 Nanopowder

Tetragonal powders : Dielectric tetragonal BaTiO₃ nanopowder was synthesized in a solvent‐less, efficient process by the thermolysis of a single [Ba₂Ti₂(thd)₄(OnPr)₈(nPrOH)₂] precursor in a closed reactor at 700 °C under autogenous pressure, followed by combustion. The BaTiO₃ nanopowder is characterized thoroughly, employing advanced morphological, compositional, structural, and thermal techniques, and the dielectric constant is accounted.

     

Numerical modeling of titanium carbide synthesis in thermal plasma reactors

Titanium carbide powders synthesized in thermal plasma reactors are virtually always contaminated by soot. Equilibrium modeling predicts a viable process window without soot formation; however, this has not been achieved in practice. A numerical model incorporating chemical kinetics, nucleation and growth, and soot formation mechanisms has been developed to investigate this process. The chemical kinetic scheme teas based on ethylene pyrolysis and methane combustion with additional reactions to account for titanium-based molecules and the free carbon species found at plasma temperatures. Nucleation and .soot formation were based on simple kinetic models. The governing equations were integrated through time using typical temperature-time histories found by computational fluid dynamic (CFD) modeling of a radio frequency plasma torch. The results indicate that the synthesis is governed by interactions between several parallel processes and that there is a delicate balance between reactant stoichiometry, system pressure, cooling rate, product formation, and soot formation. This balance may be a limiting feature of ceramic carbide production in thermal plasma reactors.     

Synthesis and modeling of new phosphorus‐containing acrylates

New methacrylate monomers containing phosphonic acid or both phosphonic and carboxylic acids were synthesized through the reaction of t‐butyl α‐bromomethyl acrylate with triethyl phosphite followed by the selective hydrolysis of the phosphonate or t‐butyl ester groups with trimethylsilyl bromide and trifluoroacetic acid. The copolymerization of these monomers with 2‐hydroxyethylmethacrylate was investigated with photodifferential scanning calorimetry at 40 °C with 2,2′‐dimethoxy‐2‐phenyl acetophenone as a photoinitiator. Quantum mechanical tools were also used to understand the mechanistic behavior of the polymerization reactions of these synthesized monomers. The propagation and chain‐transfer reactions were considered and rationalized. A strong effect of the monomer structure on the rate of polymerization was observed. The polymerization reactivities of the monomers increased with decreasing steric hindrance and/or increasing hydrogen‐bonding capacity because of the hydrolysis of the phosphonate and the t‐butyl ester groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2574–2583, 2005     

具有开放骨架结构氟化磷酸钛的水热合成及分子动力学辅助确定骨架中模板剂的位置

在水热体系中,制备了一个具有三维开放骨架结构的氟化磷酸钛化合物Ti₄(PO₄)4(HPO₄)₂F₂.[(CH₃)₂N(CH₂)₂NH₃][H₃O](简称TP-J3J=Jilinuniversity).用X射线粉末衍射、元素分析、热重分析和X射线单晶衍射对其进行了表征.单晶结构分析表明,该化合物属于三斜晶系,P1空间群,晶胞参数a=0.6353(1)nm,b=0.8699(2)nm,c=1.1069(2)nm,α=93.94(3),β=90.13(3),γ=107.96(3),V=0.5804(2)nm³,Z=2,R₁=0.0391,wR₂=0.0959,GOF=1.052.TP-J3的骨架结构可以看作是由次级结构单元(SBU)[Ti₂(PO₄)₂(HPO₄)F]通过氧桥共顶点相连构筑而成的,在a和c方向形成了两种不同的八元环孔道,两种孔道相互交叉,形成了一种“类笼”结构.通过计算模拟确定双质子化的模板剂存在于“类笼”中,模板剂与骨架原子之间存在强烈的氢键作用,可稳定骨架的结构.     

二茂铁基双酰肼化合物的制备及电化学性质

以二茂铁衍生物为原料合成了3个二茂铁基双酰肼类化合物(1,2,3);利用元素分析、红外光谱、核磁共振谱等分析了标题化合物的组成和结构,采用分光光度计测定了其紫外吸收光谱,利用循环伏安法测定了其电化学性质;并利用量子化学计算得到了1的稳定结构.结果表明,化合物1因酰基活性基团被氧化而在高电位区出现一个不可逆氧化峰;与此同时,其在低电位区出现一个不可逆的还原峰.     

Experimental Investigation of the Biofunctional Properties of Nickel–Titanium Alloys Depending on the Type of Production

Nickel–titanium alloys used in dentistry have a variety of mechanical, chemical, and biofunctional properties that are dependent on the manufacturing process. The aim of this study was to compare the mechanical and biofunctional performances of a nickel–titanium alloy produced by the continuous casting method (NiTi-2) with commercial nitinol (NiTi-1) manufactured by the classical process, i.e., from remelting in a vacuum furnace with electro-resistive heating and final casting into ingots. The chemical composition of the tested samples was analyzed using an energy dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF). Electron backscatter diffraction (EBSD) quantitative microstructural analysis was performed to determine phase distribution in the samples. As part of the mechanical properties, the hardness on the surface of samples was measured with the static Vickers method. The release of metal ions (Ni, Ti) in artificial saliva (pH 6.5) and lactic acid (pH 2.3) was measured using a static immersion test. Finally, the resulting corrosion layer was revealed by means of a scanning electron microscope (SEM), which allows the detection and direct measurement of the formatted oxide layer thickness. To assess the biocompatibility of the tested nickel–titanium alloy samples, an MTT test of fibroblast cellular proliferation on direct contact with the samples was performed. The obtained data were analyzed with the IBM SPSS Statistics v22 software. EDX and XRF analyses showed a higher presence of Ni in the NiTi-2 sample. The EBSD analysis detected an additional NiTi₂-cubic phase in the NiTi-2 microstructure. Additionally, in the NiTi-2 higher hardness was measured. An immersion test performed in artificial saliva after 7 days did not induce significant ion release in either group of samples (NiTi-1 and NiTi-2). The acidic environment significantly increased the release of toxic ions in both types of samples. However, Ni ion release was two times lower, and Ti ion release was three times lower from NiTi-2 than from NiTi-1. Comparison of the cells’ mitochondrial activity between the NiTi-1 and NiTi-2 groups did not show a statistically significant difference. In conclusion, we obtained an alloy of small diameter with an appropriate microstructure and better response compared to classic NiTi material. Thus, it appears from the present study that the continuous cast technology offers new possibilities for the production of NiTi material for usage in dentistry.     

稀土氧化物在Fe1-xO基氨合成催化剂中的作用规律

 系统考察了稀土氧化物La2O3,Nd2O3,Sm2O3,Dy2O3,Sc2O3和CeO2作为助催化剂对Fe1－xO基催化剂性能的影响．结果表明,稀土氧化物与Fe1－xO作用生成了一种作为隔离体的复合氧化物REFeO3,从而促进了催化剂的还原,这种促进作用随稀土离子半径不同呈规律性变化．添加不同稀土氧化物的Fe1－xO催化剂的还原都存在补偿效应,各系列催化剂还原反应的转效温度与所添加稀土元素的离子半径呈正比关系（CeO2除外）．稀土氧化物可以有效地提高催化剂的低温活性,其添加量的变化对催化剂活性的促进作用规律与对催化剂还原性能的促进作用规律一致．     

钛酸钠纳米带的合成、表征与气敏性能

通过钛酸丁酯与氢氧化钠浓溶液的两步水热反应合成出宽度为20～240 nm、厚度为10～40 nm、长度达几十微米的单一物相的Na₂Ti₃O₇纳米带。用X-射线衍射和电子显微镜分别表征了它们的结构和形貌。这些纳米带被加工成化学电阻型传感器以测量气敏特性。测试表明在350～400 ℃之间对丙酮、乙醇和二硫化碳具有明显感应,而对一氧化碳、苯、氨气和30%的甲醛水溶液几乎不敏感。用化学吸附模型解释其气敏机理。