Reactions of rare earth acetates with aluminum isopropoxide in ethylene glycol: Synthesis of the garnet and monoclinic phases of rare earth aluminates

The reactions of mixtures of rare earth (RE) acetates and aluminum isopropoxide (Al/RE = 3/5) in ethylene glycol at 300°C afforded amorphous products. The IR spectra of these products were essentially identical with each other and indicated the presence of an acetate group and ethylene glycol moiety. When the content of RE (La–Gd) acetate in the starting mixture was increased, a crystalline glycol complex of RE oxide acetate was also formed together with the amorphous phase, but the reactions of acetates of the smaller RE ions (Tb–Lu) yielded amorphous products with wider compositions (Al/RE = 5/3–1/6). Phase-pure RE3Al5O12 (garnet) and RE4Al2O9 (monoclinic) were obtained by calcination of the amorphous products with the corresponding stoichiometric compositions at low temperatures.     

Synthesis of nanocrystalline rare earth oxides by glycothermal method

The reaction of yttrium acetate hydrate in 1,2-propanediol at 300 °C yielded a product containing acetate groups and glycol moieties. From this product, Y₂O₃ was directly crystallized at 400 °C without the formation of a carbonate oxide phase. The thus-obtained Y₂O₃ samples had a small crystallite size (2.2 nm) and significantly large surface area (280 m²/g). Other nanocrystalline rare earth (Gd-Yb) oxides were also obtained by this method.     

Synthesis and morphological control of rare earth oxide nanoparticles by solvothermal reaction

Eu doped Y₂O₃ and some kinds of other rare earth oxides nanoparticles such as Er₂O₃, Nd₂O₃, Ho₂O₃, Lu₂O₃, and Dy₂O₃ were prepared by a simple co-precipitation-solvothermal treatment-calcination process, where the co-precipitated amorphous hydroxide precursors obtained by adding rare earth nitrate solutions in ammonia solutions were heated in solvents such as water, alcohols and glycols, followed by calcination in air. The morphology of rare earth oxide particles strongly depended on the solvothermal reaction medium but not related to the kind of rare earth oxide. The powders prepared in water and ethanol possessed nanowire structure, where the aspect ratio of powder treated in water was higher than that in ethanol. The powders prepared by co-precipition-solvothermal treatment-calcination process using ethylene glycol consisted of near-spherical nanoparticles whereas that prepared by conventional co-precipitation-calcination method consisted of hardly agglomerated submicron particles. The nanoparticles of Eu³⁺ doped Y₂O₃ prepared by co-precipition-solvothermal treatment-calcination process showed similar intensity of photoluminescence with the submicron particles by co-precipition-calcination process.     

稀土铕四元配合物纳米微晶的制备及性能

为了得到粒径均匀的纳米稀土铕四元配合物,采用化学沉淀法,进一步优化试验条件,制备Eu(BA)(TTA)2邻菲罗林纳米微晶,采用元素分析、红外光谱、热重分析、荧光光谱和透射电镜等方法对其进行表征和分析。结果表明,稀土铕四元配合物中高效率的能量传递是通过在2种不同第一配体之间形成的"协同效应"来完成,四元配合物中3种不同的配体可以更好地取代配位水;四元稀土配合物不仅发光性能优于常见的三元配合物,而且热稳定性好,粒径较小且均匀,可进一步掺入高分子形成功能性含稀土高分子聚合物;选用合适的缓冲溶液,在调节pH时将缓冲溶液缓慢地逐滴加入,可采取往反应体系中通氨气的方法,以使体系的pH改变较为平稳,生成的沉淀粒径较小且均匀。     

2,2,2-胺三乙酰二苄胺及其稀土配合物的合成、表征与荧光性质

为研究三脚架型配体稀土配合物的组成、可能的配位状态及荧光性质,合成了三脚架型配体--2,2,2-胺三乙酰二苄胺(L)及其6个稀土配合物.通过红外光谱、核磁共振波谱、元素分析、差热-热重分析、摩尔电导率及荧光光谱等方法对L及其稀土配合物的组成及性质进行了表征.结果表明, L能够与稀土离子配位,生成n(RE)∶n(L)=1∶1的配合物;Tb(Ⅲ)配合物在紫外光激发下,在490nm、545nm、590nm、620nm附近出现强度不同的Tb3+特征荧光发射峰,分别归属于Tb3+的5D4→7F6、5D4 →7F5、5D4→7F4、5D4→7F3能级跃迁;而其Eu(Ⅲ)配合物的荧光发射微弱,其它配合物没有荧光发射.说明L的三重态能量与Tb3+最低激发态能级匹配较好,能起到较好的敏化作用,提高Tb3+的发光强度.     

Measuring adhesion between steel and early-hydrated Portland cement using particle probe scanning force microscopy

Particle probe scanning force microscopy was used to measure adhesion between steel and early-hydrated cement in the study. Particle probes, created by attaching steel microspheres to microcantilevers, were successfully used to collect adhesive forces between steel and early-hydrated Portland cement in air and in saturated lime water. Mixed Gaussian models were applied to predict phase distributions in the cement paste, i.e., low density calcium silicate hydrate, high density calcium silicate hydrate, calcium hydroxide, other hydrated products and the unreacted components. Consistent correlations were achieved for volume fractions between areas with different adhesion measurements and predictions from the hydration model. Results showed that low density calcium silicate hydrate, high density calcium silicate hydrate and other hydrated products exhibit intermediate adhesion to steel microspheres. Calcium hydroxide exhibits the smallest adhesion, while the unreacted components exhibits the largest adhesion among all groups.     

Mechanism of preparing ultrafine copper powder by polyol process

Ultrafine copper powder was prepared in ethylene glycol in which sodium hydroxide was added. By the analysis of XRD, FTIR and SEM, a reasonable reaction mechanism was presented. The formation of copper powder and the oxidation of ethylene glycol were researched.     

Mixed-solvothermal synthesis of hybrid nanostructures of alkaline earth phenylphosphonates

Hybrid nanostructures such as nanoflowers, nanosheets and nanoribbons of the alkali earth phenylphosphonates were prepared via mixed-solvothermal approaches by reaction of alkali earth metal salt with phenylphosphonate in ethylene glycol. The final products have been characterized with X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FT-IR), and Thermogravimetry (TG). Effects of reaction parameters on the formation of two-dimensional nanostructure were discussed. This work may provide a simple and effective approach to control the microstructures of the metal phenylphosphonates, which will be of great importance for the controlled synthesis of hybrid nanostructures and further applications.     

醇化法合成碲醇盐及其Sol-gel法制备碲酸盐薄膜

以二元醇和TeO_2为反应物,通过醇化反应合成金属碲醇盐.利用FT-IR、Raman、DTA和OM测试手段研究了醇化反应过程及产物性质.结果发现,以反应活性高的乙二醇和1,2丙二醇为反应物可以合成出乙二醇碲和1,2丙二醇碲.与1,2丙二醇碲相比,乙二醇碲聚合程度相对较高,因此,其溶解性差、熔点高;而1,2丙二醇碲溶解性好、熔点低.XRD和FE-SEM分析表明,采用本实验合成的1,2丙二醇碲,通过溶胶一凝胶法可制备出适用于光电器件的碲酸盐薄膜材料.     

铕(Ⅲ)-4-VP光致发光稀土配合物单体的制备

以 4 乙烯基吡啶 (4VP)、邻菲洛啉 (Phen)为配体 ,与EuCl3 在乙醇溶液中一步合成了含有双键的三元稀土配合物 ,通过紫外光谱与荧光光谱的测定 ,研究稀土配合物光致发光的机理。结果表明 ,4 乙烯基吡啶通过吡啶环上的氮原子与稀土离子可直接配位 ;邻菲洛啉配体具有协同配位效应。稀土配合物较EuCl3 的荧光发射强度提高了 12倍之多。     

Trace Determination of Glycols by HPLC with UV and Electrospray Ionization Mass Spectrometric Detections

A high-performance liquid chromatography/mass spectrometry (HPLC/MS) method is developed for trace determination of glycols (ethylene glycol, 1,2- and 1,3-propylene glycols, and 2,3-butylene glycol) in water after derivatization with benzoyl chloride. Benzoyl esters of glycols are separated by microcolumn reversed-phase HPLC. Sensitivity and linearity of UV detection at 237 nm is compared with electrospray ionization mass spectrometric (ESI-MS) detection using selected ion monitoring. Limits of detection (LOD) and quantitation (LOQ) for UV detection are 1 and 2 mg/L, respectively. For ESI-MS detection, LOD and LOQ are in the ranges 10-25 and 20-50 μg/L, respectively. LOD obtained by ESI-MS for the determination of glycols is improved by 2-3 orders of magnitude in comparison to previously published methods. The effect of the structure of isomeric glycols on their electrospray mass spectra is discussed. The method has been applied for the determination of glycols in aqueous matrixes containing high concentrations of salts occurring in nuclear waste disposal treatment.     

Revised viscosities for HFC-134a + glycol mixtures from 273 to 333 K

The liquid viscosity of six binary mixtures of HFC-134a with glycols [ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol(400), and polypropylene glyco](2000)] was measured in the temperature range from 273 to 333 K. The viscosity was measured with an improved capillary viscometer instead of the rolling-ball viscometer reported in our previous work. The measurement uncertainty was estimated to be 1.6%. Most of the present data are higher than previous data, and the gap between the two sets of data increases further in low-viscosity regions. The present results obtained with laminar flow are more reliable than previous results, which are indefinite because of the limit of usefulness of the rolling-ball viscometer in low-viscosity regions.     

稀土铕高分子荧光配合物的制备及性能研究

稀土配合物作为发光材料已广泛应用于众多领域,为了使材料获得更稳定更持久的发光性能,本文以N-乙烯基甲酰胺(NVF)和丙烯酰胺(AM)为共聚单体,水为溶剂,在高温、引发剂条件下经自由基溶液聚合制备出含有氨基、羧基等多种配位官能团的水溶性高分子聚合物两性聚乙烯胺(PVAm),并以此作为高分子配体,再辅以1,10-邻菲咯啉(phen)作为第二配体,用三价稀土离子铕(Eu)的盐溶液与之配位,制备出具有优良荧光效应的稀土配合物Eu(PVAm)_3phen荧光粉。对高分子配体PVAm进行IR、NMR等分析,找出配位官能团,并对稀土配合物的外观形貌进行荧光显微镜等观察分析,对配合物的结构进行XRD等表征,并分析其紫外光谱、荧光光谱、荧光余辉亮度。配合物在220～275 nm范围内对紫外光有较强的吸收,最大吸收峰在260 nm处。配合物在580、593、614、650 nm的4处有明显的荧光发射峰。     

稀土络合催化甲基丙烯酸丁酯聚合

本文研究稀土化合物与三异丁基铝组成络合催化剂聚合甲基丙烯酸丁酯(BMA),考察催化剂的组分比、溶剂、不同的稀土元素和配体对聚合的影响。结果表明,La、Pr、Nd、Eu、Gd、Er、Yb、Lu等八种稀土元素的膦酸酯化合物都具有聚合催化活性。用ESR、GPC、~1H-NMR等技术研究聚合物的结构与性能,表明聚合反应属配位自由基机理。     

银纳米线的溶剂热合成与表征

以聚乙烯吡咯烷酮(PVP)为表面活性剂、乙二醇为溶剂,通过简易的溶剂热方法合成了银纳米线.结果表明,在反应体系中乙二醇不仅能作为溶剂,而且还能起到还原剂的作用.用XRD、SEM对产物进行了表征.考察了乙二醇和PVP用量等对银纳米线合成的影响;找出了合成的较佳条件.对银纳米线的合成机理进行了初步探讨.     

In vivo Retention Time Evaluation of Polyethylene Glycol Suppository Bases

Ninety six (96) healthy male volunteers between the ages of 21 and 35 received two experimental polyethylene glycol suppository bases and one commercially available base. A comparison of the two experimental bases with the commercially available base indicates that the base containing polyethylene glycol 1000-4000 (65:35) is superior and that the base containing polyethylene glycol 1540-6000 (30:70) is probably comparable to the commercial product. It is concluded that these polyethylene glycols can be used as suppository bases without undue reaction.     

Corrosion-electrochemical behavior of aluminum alloys in aqueous ethylene glycol media

Using the method of mathematical design of experiments, we have studied the influence of ethylene glycol concentration and temperature over a wide range of their variation on the corrosion of AMg₃ aluminum alloy. We have established that, irrespective of the ethylene glycol concentration, the maximum corrosion losses are observed at temperatures of 60–70°C. The inhibiting action of ethylene glycol at concentrations exceeding 40% is caused by an increase in the viscosity of the solutions and by the formation of slightly soluble surface complexes of aluminum with ethylene glycol and the products of its oxidation. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 6, pp. 86–93, November–December, 2007.     

稀土配合物杂化材料的制备与性能研究

综述了近年来稀土配合物杂化材料的制备和性能．按基质的不同，稀土配合物杂化材料可分为稀土配合物，无机杂化材料，稀土配合物，有机杂化材料以及稀土配合物，混合基质杂化材料。本文对以上3种杂化材料的优缺点进行了较为详细的分析，并提出一步法制备稀土配合物杂化材料，以简化合戍步骤，提高稀土配合物在基质分布的均匀性，因而该方法有望戍为制备稀土配合物杂化材料的一个重要发展方向。     

Synthesis, magnetic properties and catalytic activity of hierarchical cobalt microflowers

A simple one pot synthesis method for the silver catalyzed growth of pure hexagonal close packed cobalt by the reduction of cobalt salt using hydrazine hydrate in the presence of triethanolamine (TEA), diethanolamine (DEA) and ethylene glycol (EG) as capping agents at 90 degrees C within 10 min has been reported. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the product prepared in the presence of capping agents show the formation of the well defined porous flowery architecture originating from the interlinked 2D wavy nanoflakes. When the same reaction is performed in the absence of any capping agent, the agglomeration of the flakes of cobalt with irregular spherical morphology is observed. The effect of the reaction conditions on the size and the shape of the products have also been studied. Vibration sample magnetometer (VSM) shows, that the products are ferromagnetic in nature irrespective of the capping agents used and possess high value of coercivity, when prepared in the absence of any capping agent. These cobalt microflowers have also been proved as an alternative to the other available expensive catalysts (Au, Ag, Pt) in the room temperature production of p-aminophenol for its applications in pharmaceutical, photographic and plastic industries.     

Controllable fabrication of various ZnO micro/nanostructures from a wire-like Zn-EG-AC precursor via a facile solution-based route

In this paper, ZnO particles with various morphologies were prepared though a facile solution-based route. The complexes Zn-EG-AC (EG: ethylene glycol; AC: CH₃COO⁻ groups) obtained by reaction of anhydrous zinc acetate and EG were used as precursors. It is found that the precursor could transform into ZnO in water with no need of assistant of additional alkali as it is sensitive to water. At the same time, it is well dispersed in reaction medium (water and ethanol). Experimental results showed that ZnO particles with various morphologies, such as the hexagonal rings, the hexagonal plates, the tubes, the prisms, and some interesting hierarchical structures, could be obtained by controlling hydrolysis of precursor in water and water/ethanol medium through finely tuning the experimental parameters. The success of shape-controllable fabrication was related intimately with the Zn-EG-AC precursor used in our synthesis.