一类新的4-取代胂酸型变色酸偶氮多卤显色剂的合成及其与稀土元素显色反应的研究

本文研究了五个结构新颖的显色剂与稀土元素的显色反应。其中的二溴羧基偶氮氯肿(CAsA-DBK)与稀土元素反应具有对比度大、灵敏度高、选择性好等优点。在0.6mol/LHClO_4介质中,不加任何掩蔽剂条件下,只与铈组稀土显色,与钇组稀土几乎不显色,是一个较有特色的铈组稀土试剂。     

New Rare Earth（Ⅲ） Complexes with H2tmtaa

A series of Ln(tmtaa)(Htmtaa)·CH_2Cl_2(Ln=Sm,Tb,Er and Yb)complexes were prepared and characterized byinfrared spectra,mass spectra and molecular electronic spectroscopy as well as DSC measurement.A sandwichstructure containing all the eight nitrogen atoms of tmtaa and Htmtaa was proposed for these complexes.X-rayphotoelectron spectra(XPS)of these complexes revealed that four nitrogen atoms of both tmtaa and Htmtaa werechemically equivalent to each other,respectively.The acidic hydrogen of Htmtaa did not bind specifically to any ni-trogen atom of Htmtaa,but was shared by all the four nitrogen atoms.The magnetic properties of these complexeswere found to be in good agreement with their theoretical values.     

Addition of nitriles to alkaline earth metal complexes of 1,2-bis[(phenyl)imino]acenaphthenes

Compounds [Sr(dpp-bian)(thf)4] (2), [Ba(dpp-bian)(dme)2.5] (3) and [Mg(dtb-bian)(thf)2] (4) (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; dtb-bian = 1,2-bis[(2,5-di-tert-butylphenyl)imino]acenaphthene) were prepared by reduction of dpp-bian and dtb-bian with an excess of metallic Mg, Sr, or Ba in THF or DME. Reactions of [Mg(dpp-bian)(thf)3], 3, and 4 with diphenylacetonitrile gave keteniminates [Mg(dpp-bianH)(NCCPh2)(thf)2] (5), [Mg(dtb-bianH)(NCCPh2)(thf)2] (6), and [Ba(dpp-bianH)(NCCPh2)(dme)2] (7), respectively. The reaction of 2 with CH3C[triple chemical bond]N in THF gave [{Sr(dpp-bianH)[N(H)C(CH3)C(H)CN](thf)}2] (8). The compounds 2, 3, 5-8 were characterized by elemental analysis, and IR and NMR spectroscopy. Molecular structures of 2, 3, 7, and 8 were determined by single-crystal X-ray diffraction. In contrast to reactions of alkali-metal reagents, magnesium amides, or yttriumalkyls with alpha-H acidic nitriles, which are accompanied by an amine or an alkane elimination, the reactions of [Mg(dpp-bian)(thf)3] (1), 2, 3, and 4 with such nitriles proceeded with formation of Mg, Sr, and Ba keteniminates and simultaneous protonation of one nitrogen atom of the bian ligand. The NMR spectroscopic data obtained for complex 5 indicated that in solution the amino hydrogen atom underwent the fast (on the NMR timescale) shuttle transfer between both nitrogen atoms of the dpp-bianH ligand.     

Influence of the texture of chromia catalysts on their activity in synthesis of 2-methylthiophene

The texture of Cr₂O₃-K₂O/Al₂O₃catalysts containing oxides of rare earth elements (REE) was studied. The catalysts are used for the synthesis of 2-methylthiophene by the reaction of H₂S with n-pentane or piperilene. The heterocyclization of n-pentane is a consecutive reaction involving a step of dehydrogenation of initial hydrocarbon. At this step the texture of the catalyst affects the yield of 2-methylthiophene. The yield of 2-methylthiophene obtained from piperilene and I₂S is independent of the catalyst texture.     

Synthesis of New Lithium Ionic Conductor Thio-LISICON—Lithium Silicon Sulfides System

The new lithium ionic conductors, thio-LISICON (LIthium SuperIonic CONductor), were found in the ternary Li₂S-SiS₂-Al₂S₃ and Li₂S-SiS₂-P₂S₅ systems. Their structures of new materials, Li_4+xSi_1−xAl_xS₄ and Li_4−xSi_1−xP_xS₄ were determined by X-ray Rietveld analysis, and the electric and electrochemical properties were studied by electronic conductivity, ac conductivity and cyclic voltammogram measurements. The structure of the host material, Li₄SiS₄ is related to the γ-Li₃PO₄-type structure, and when the Li⁺ interstitials or Li⁺ vacancies were created by the partial substitutions of Al³⁺ or P⁵⁺ for Si⁴⁺, large increases in conductivity occur. The solid solution member x=0.6 in Li_4−xSi_1−xP_xS₄ showed high conductivity of 6.4×10^-4 S cm⁻¹ at 27°C with negligible electronic conductivity. The new solid solution, Li_4−xSi_1−xP_xS₄, also has high electrochemical stability up to ∼5 V vs Li at room temperature. All-solid-state lithium cells were investigated using the Li_3.4Si_0.4P_0.6S₄ electrolyte, LiCoO₂ cathode and In anode.     

负载稀土型酸活化膨润土的酯化催化活性

负载稀土型酸活化膨润土的酯化催化活性李永绣，冯天泽，胡平贵，何小彬，辜子英，廖荣辉（南昌大学化学系南昌３３００４７）关键词稀土，膨润土，催化酯化可用稀土、膨润土单独作酯化催化剂，但活性不高［１～３］。本文将稀土用离子交换的方法负载到酸活化膨润土中，寻...     

醇盐法制备稀土化合物超微粉末

稀土元素具有广泛的用途,在大多数的应用中其效果都与原料的纯度、粒度、粒经分布范围等因素有关。由于超微粉末的比表面积大、化学活性高,因此可以预料,若将稀土化合物制成超微粉末,会使它的催化性能及在各种材料中的性能有明显的改变,也可使稀土有新的、更高的应用价值。     

Separating Ag, B, Cd, Dy, Eu, and Sm in a Gd matrix using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester extraction chromatography for ICP-AES analysis

The separation procedure for Ag, B, Cd, Dy, Eu and Sm as impurities in Gd matrix using ICP-AES technique with an extraction chromatographic column has been developed. The spectral interference of the Gd matrix on the elements was eliminated using a chromatography technique with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) as the mobile phase and XAD-16 resin as the stationary phase. Ag⁺, B₄O₇²⁻, and Cd²⁺ were eluted with 0.1 M HNO₃, while rare earth ions were not. The best eluent for separating Eu and Sm in the Gd matrix was 0.3 M HNO₃. The limit of quantitation for these elements was 0.6-3.0 ng mL⁻¹. The recovery of Ag, B, and Cd was 90-104% using 0.1 M HNO₃ as the eluent, while that of Eu, Gd, and Sm ranged from 100 to 102% with 0.3 M HNO₃. Dy was recovered quantitatively with 4 M HNO₃. The relative standard deviation of the methods for a set of three replicates was between 1.0 and 15.4% for the synthetic and standard Gd solutions. The proposed separation procedure was used to measure Ag, B, Cd, Dy, Eu, and Sm in a standard Gd solution.     

Kinetics and mechanism of gold dissolution in thiourea solutions: Effect of sulfide ions

Chronoamperograms for gold in solutions containing 0.1 M thiourea, 0.5 M H₂SO₄, and catalytically active sulfide ions at the concentration c ₁ from 1 × 10^?5 to 4 × 10^?5 M are obtained at different potentials with the aid of an automated setup intended for renewing the electrode surface directly in the solution by cutting off a thin surface layer of the metal. It is shown that the results of measurements of the current practically coincide at a constant value of the product c ₁ t, where t is the time period elapsed after the renewal of the electrode surface. Such a coincidence testifies to a diffusion nature of processes that hamper accumulation of sulfide ions at the gold surface. This fact permitted the use of a procedure developed previously for the calculation of polarization curves at constant values of surface coverage θ by catalytically active ions. At θ = const, the voltammetric curves for gold in sulfide-containing thiourea solutions are shown to correspond to the Tafel equation. With the surface coverage increasing, the effective values of the exchange current i ₀, transfer coefficient α, and anodic reaction order with respect to thiourea P _a increase from the values i }~ 10^?5 A cm^?2, α }~ 0.12, and P _a = 0.2, which are characteristic of pure solutions, to 2 × 10^?4 A cm^?2, α }~ 0.5, and P _a = 1.1 (at θ }~ 0.5). An interpretation to the established regularities is given.     

钇对金属陶瓷力学性能和组织的影响

研究了添加钇对Ｔｉ（Ｃ，Ｎ）基金属瓷力学性能和组织的影响。结果表明，加入适量的钇能提高Ｔｉ（Ｃ，Ｎ）基金属陶瓷的抗变强度和硬度，其原因是由于钇与杂质硫起反应在化合物，净化了陶瓷相－金属相，陶瓷相－陶瓷相界面提高子界面结合强度