RE-NTA-Ser·nH2 O三元配合物的合成与表征

合成了5种稀土-氨三乙酸-丝氨酸三元配合物,并用元素分析、热分析、红外及X-射线光电子能谱进行了表征.     

Role of defect structure of active oxides in oxidative coupling of methane

A new approach to the choice of catalysts for oxidative coupling of methane based on the determination of the defect degree is suggested. For the most active catalysts (oxides of rare earth elements (REE), alkaline earth metals (AEM), manganese, lead), it is shown that oxygen defectness is of great importance in this process.Based on the structural approach Bi₂O₃-containing catalytic systems have been suggested. They have C₂-hydrocarbon formation activity and selectivity to be comparable with those ones for most active catalysts as REE oxides.     

Unusual Elution Sequence of Rare Earth Elements (REE) in Some Ion Chromatographic Systems and the Effect of Temperature

Ion chromatographic separation of rare earth elements (REE) was studied using isocratic elution from Dionex Ion Pac CS3 + CG3 column with sulfonic acid functional groups and buffered solutions of tartaric (HTart), citric (HCit) and nitrilotriacetic (NTA) acids, respectively, at temperatures 25–70°C. Apparent atomic numbers (App.At.No.) of Y and Sc with respect to lanthanide series were established and found to vary widely both with the ion exchange system and with temperature. A novel method for the separation of Dy-Y-Tb triad was proposed using 68 m mol L^?1 HCit, pH = 3.18 at T = 60°C and its capability to be used for analytical determinations was demonstrated. The significance of contribution of longitudinal diffusion in the stationary phase to total zone spreading in the systems studied was emphasized.     

Mechanism of degradation of nitrilotriacetic acid by heterogeneous photocatalysis over TiO2 and platinized TiO2

TiO₂-heterogeneous photocatalysis of nitrilotriacetic acid (NTA) at pH 2.5 was studied to establish the kinetic regime and the reaction mechanism. Pure Degussa P-25 and Hombikat UV100 commercial samples were compared. A Langmuirian behavior was observed over P-25. Platinization of the Hombikat sample (0.5 wt.%) caused an important increase on the photocatalytic rate with a change in the kinetics from zero order in the pure precursors to first order in the platinized sample. The nature of the intermediates and their evolution with time were compared on all systems. Glycine, iminodiacetic and oxamic acids have been identified in different proportions, together with ammonium and glycolic acid, depending on the catalyst used. The rapid depletion of NTA was not accompanied by a corresponding total organic carbon (TOC) reduction, but 84% of TOC decrease was obtained on P25 after 24 h, a very reasonable result for refractory compounds. A detailed mechanism is proposed for the photocatalytic reaction, suggested to be the same over the three catalysts here tested.     

Oxidative absorption of hydrogen sulfide using an iron‐chelate based process: chelate degradation

BACKGROUND: Oxidative absorption of hydrogen sulfide into a solution of ferric chelates is studied in a stirred cell glass reactor. The experiments were performed to investigate the degradation of chelates sodium salt of nitrilotriacetic acid (NTA) (Merck), ethylenediaminetetraacetic acid diadisodium salt (EDTA) and diethylenetriaminepentaacetic acid (DTPA) at 313 K, pH 6, iron concentration 10 000 g L^?1 and Fe:chelate molar ratio 1:2. RESULTS: Oxidative absorption of hydrogen sulfide into a solution of Fe‐NTA was found to be more successful, therefore, further experiments with 10%, 50% and 100% concentrations of hydrogen sulfide were performed. It was shown that this process is applicable for removal of low and high concentrations of hydrogen sulfide. The effect of antioxidants using sodium thiosulfate was also studied in order to minimize degradation of NTA. The kinetics were studied and it was observed that the reaction appeared to be first order in ferric chelate with rate constants for 100, 50 and 10% hydrogen sulfide concentration: 0.035, 0.013 and 0.019 h^?1, respectively. CONCLUSIONS: Gas sweetening processes have commercial importance in natural gases, refinery of gases and biogas processing. Desulphurization and cleaning (i.e. removal of H₂S and CO₂) of petroleum gas and biogas is important to make the gas methane rich and to increase the calorific value of fuel. The same techniques of desulphurization and cleaning can be used for treating natural gas or petroleum gas. The desulphurization and cleaning processes can minimize the atmospheric emission of gases like SOx, NOx and CO. As the iron chelate based process is based on the principle of redox reaction of metal chelate with hydrogen sulfide, this method is very useful for desulphurization of petroleum gas and biogas. This work studied the effective use of Fe‐NTA solution for removal of high to low concentrations of H₂S as found in biogas and industrial waste gases. © 2012 Society of Chemical Industry     

温度和PH值对环烷酸稀土有机化合物合成的影响

本文研究温度、PH值对环烷酸稀土有机化合物合成的影响。     

环烷酸萃取法从氯化矿泥水浸液中分离稀土元素 1.萃取前除杂

川西稀土矿泥氯化后水浸液中,稀土含量较低,可借助环烷酸萃取法分离出稀土元素。水浸液组成复杂,导致环烷酸易乳化流失,故萃取前需除杂。着重讨论用高锰酸钾除铁的机理和实验控制条件。     

茴香调味品中稀土元素的电感耦合等离子体质谱分析

建立了一种电感耦合等离子体质谱法测定茴香调味品中痕量稀土元素的方法。利用该方法分析了国家标准物质(GBW 07605)中的稀土元素,结果与标准值一致。该方法被用于分析茴香调味品实际样品中的稀土元素,结果令人满意。     

Highly Active and Diastereoselective N,O‐ and N,N‐Yttrium Complexes for Intramolecular Hydroamination

The intramolecular hydroamination of aminoalkynes and unactivated aminoalkenes catalyzed by yttrium N,O‐ and N,N‐complexes has been investigated. The N,N‐yttrium complexes are highly active, catalyzing the conversion of a wide range of terminal aminoalkenes at room temperature, and internal aminoalkenes at elevated temperature, to yield pyrrolidine and piperidine products in high yields. A high diastereoselectivity of up to 23:1 is observed at 0 °C with 1‐methyl‐4‐pentenylamine as substrate.     

高良姜中稀土元素的电感耦合等离子体质谱分析

建立了一种电感耦合等离子体质谱法测定高良姜中稀土元素的方法。利用该方法分析了国家一级灌木枝叶标准物质(GBW07603)中的稀土元素，结果与参考值一致。该方法被用于分析高良姜样品中的稀土元素，得到令人满意的结果。     

神经网络动力学光度法同时测定烟草中铈和镧

在酸性介质中Ce4＋和La3＋同时阻抑溴酸钾氧化甲基红褪色反应,研究发现：两者对溴酸钾氧化甲基红褪色反应阻抑作用不具有加和性,根据这一现象,用人工神经网络处理非线性体系的优势进行数据处理,从而建立了一种同时测定Ce4＋和La3＋混合物的人工神经网络阻抑动力学光度法。对3种烟草样品进行测定,回收率位于95.0%~104.0%之间,RSD均小于4%,结果良好。     

Behavior of Actinium,Alkaline, and Rare Earth Elements in Sr-Resin/Mineral Acid Systems

In this work, the interactions between the divalent alkaline earth elements (AEE) (Sr, Ba, Ra), the trivalent rare earth elements (REE) (Ce-Lu, Y), and Ac(III) with Sr-resin were investigated in the presence of HNO₃, HCl, HBr, HClO₄, and HPF₆. Distribution coefficients of these ions on the Sr-resin were determined under batch-loading conditions. Lastly, online column separations were performed to demonstrate the utility of these systems. Substantial differences in the behavior of the ions in solutions comprised of the five different acids were observed. These differences can partly be explained by a combination of ion exchange (primary) and extraction (solvation) mechanisms. From a practical point of view, the Sr-resin/HClO₄ or Sr-resin/HPF₆ systems were demonstrated to be effective for the separation and purification of the different groups of the elements.     

Studies on extraction and permeation of lanthanum(III) and cerium(III) using cyphos IL 104 as extractant and ion carrier

ABSTRACT

This work shows application of Cyphos IL 104 (trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate) as the extractant and the ion carrier of Ce(III) and La(III) from aqueous solutions through polymer inclusion membranes (PIM). These membranes were used for separation of Ce(III) from solution containing La(III), Cu(II), Co(II) and Ni(II). The best results of the separation process were obtained for PIM containing: 20.0 wt.% CTA, 55.0 wt.% NPOE and 25.0 wt.% Cyphos IL 104 at pH 3.8 into 1 M H₂SO₄. The separation coefficients were found in order of S _Ce/La < S _Ce/Cu < S _Ce/Co < S _Ce/Ni.     

纳米氧化钇的制备与表征

以Y(NO3)3为原料,聚乙烯醇为分散剂,采用碳酸氢铵沉淀工艺制备了氧化钇前驱体。用FTIR、TG-DTA分析了沉淀前驱体的成分及其热分解过程。结果表明,前驱体为NH4Y(OH)2CO3。对形成前驱体的机理进行了初步探讨。用XRD、UV-Vis和TEM分析了不同温度下煅烧所得粉体的结构和形貌,结果表明,前驱体在750℃保温2h,得到分散性良好、纯度高、立方体型的氧化钇,平均颗粒尺寸20nm左右。实验证明,适量的分散剂和(NH4)2SO4的添加对氧化钇颗粒形貌和粒径有显著影响。     

稀土元素对脂肪醇胺化催化剂性能的影响

无论是作为脂肪醇胺化催化剂的活性组分还是载体 ,La和Gd均能提高目前工业用Cu—Ni催化剂的活性和选择性 ,可以使生成的高沸物小于 2 % ,二甲基叔胺的收率大于 97% ,而Nd和Ce则无明显的促进作用。这些稀土元素均对催化剂的稳定性没有改善     

用二溴羧基偶氮胂光度法测定陶瓷中微量铈组稀土

本文确立了一种测定陶瓷中铈组稀土总量的分析方法。在酸性介质中,试剂与铈组稀土(镧、铈、镨、钕、钐)有灵敏的显色反应。(ε=1.40×10     

Interactions between poly(acrylamide)–poly(itaconic acid) and cerium(IV)–nitrilotriacetic acid redox pair in the synthesis of acrylamide and itaconic acid homo‐ and copolymers

Homopolymers of itaconic acid (PIA) and its copolymers with acrylamide (P(IA‐AAm) were synthesized using ceric ammonium nitrate (NH₄)₂Ce(NO₃)₆ in combination with nitrilotriacetic acid (NTA) as redox initiator, and potassium persulphate at pH 1. The chain structures of the resulting products have been studied by FTIR spectroscopy. It is concluded from a comparison of spectroscopic results with gravimetric and viscometric data that the depressions in the yields and viscosity numbers in the case of Ce(IV)–NTA redox pair result from interactions between the constituents of the redox initiator and IA. Spectra of the insoluble and pale yellow precipitates, which are formed during the first 4 h of the reaction, after addition of Ce(IV) solution to the NTA and NTA–IA homogeneous solutions, also indicate the presence of various oxidation products. Furthermore, it is observed that H‐bonded homopolymer complex obtained from PAAm–PIA blends, prepared from aqueous solutions containing equal unit moles of each polymer, contain both ordered and defective structures. © 2001 Society of Chemical Industry     

饲料级柠檬酸稀土制备条件研究

对饲料级柠檬酸生产中的酸度,原料用量,温度,沉淀条件等进行了实验,测定了该产品中ＲＥ２Ｏ３％及Ｐｂ,Ａｓ,Ｃｄ,Ｈｇ等有害元素含量,通过动物急性毒理实验,蓄积性实验,证明了该产品无毒,无残留,为养殖业的安全使用提供了科学依据。