十钨钼钒锗杂多酸复合二氧化硅凝胶的制备与质子导电性

通过溶胶-凝胶法制备了掺杂十钨钼钒锗杂多酸的二氧化硅凝胶,红外光谱证明了凝胶中有Keggin[GeW10MoVO40]5-结构的阴离子存在．在室温(18℃)下,掺十钨钼钒锗酸71％的凝胶的质子电导率为1．97×10-3S·cm-1,它们是好的质子导体．     

Synthesis and conductivity of undecatungstotitanotitanic heteropoly acid

The undecatungstotitanotitanic heteropoly acid H₄[Ti(H₂O)TiW₁₁O₃₉] 7H₂O was synthesized for the first time by the stepwise acidification and the stepwise addition of solutions of the component elements as well as the ion exchanging-cooling method. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), i.r., u.v., X-ray diffraction and thermal analysis. The i.r., u.v. and XRD indicate that H₄[Ti(H₂O)TiW₁₁O₃₉] 7H₂O possesses the Keggin structure. The results of AC impedance measurement show that its proton conductivity is 1.39 × 10⁻³ S cm⁻¹ at room temperature (16 °C).     

Catalysis by porous heteropoly compounds

This paper attempts to review recent works on catalysis of porous heteropoly compounds. The salts of heteropolyacids having Keggin structure with large cations like Cs⁺ are porous materials. For Cs hydrogen salts, the pore width can be controlled by the Cs content. Cs_2.5H_0.5PW₁₂O₄₀ has the largest amount of protons on the surface among the acidic Cs salts and possesses pores with bimodal distribution in the micro and meso region. Efficient performances were demonstrated for acid-catalyzed reactions such as skeletal isomerization of -butane in solid-gas system, alkylation and acylation in solid-liquid system, and hydrolysis and hydration in solid-water system. A microporous salt, Cs_2.2H_0.8PW₁₂O₄₀, exhibited reactant shape selectivity towards direct decomposition of esters. Furthermore, an ultramicroporous bifunctional catalyst, Pt–Cs_2.1H_0.9PW₁₂O₄₀ of which the pore width is around 5 Å, exhibits reactant shape selectivity for hydrogenation of alkenes and oxidation of hydrocarbons, and product shape selectivity for skeletal isomerization of -butane.     

含钨杂多酸对钢铁腐蚀行为的影响(英)

采用失重法研究了含钨杂多酸在ＮａＣｌ 溶液中对钢铁腐蚀行为的影响．实验结果表明所研究的杂多化合物对钢铁均具有一定的缓蚀作用．但杂多酸盐特别是缺位型杂多酸盐的缓蚀效果较好．     

Oxidation of methylbenzenes by heteropoly compounds in solution

Conclusions heteropoly compounds in acetic acid solution oxidize methylbenzenes to form mixtures of aromatic alcohols, aldehydes, di- and polyarylmethanes. The reaction may be carried out catalytically in the presence of oxygen. Results were obtained indicating the formation of an intermediate radical-cation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheska, No. 5, pp. 1010–1017, May, 1984.     

Electron transfer in solutions of tungstovanadophosphoric heteropoly compounds

Redox properties of some isomers of tungstovanadophosphoric heteropoly anions have been studied. Rate constants of electron transfer from -1, 2, 3-PW₉V ₂ ^V V^IVO ₄₀ ^7– to PW₁₁V^VO ₄₀ ^4– (k=1.1±0.2)×10² dm³/mol s) and from PW₁₀V^VV^ivO ₄₀ ^6– to -1,2,3-PW₉V ₃ ^V O ₄₀ ^6– (k=1.4±0.2)×10² dm³/mol s) have been measured in 30% CH₃COOH at pH 3 and 20°C.

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- . PW₁₁V^VO₄₀ ^4– -1,2,3-PW₉V ₂ ^V V^ivO₄₀ ^7– (k=(1,1±0,2)·10^{2 3}/·), -1,2,3-PW₉V ₃ ^V O₄₀ ^6– PW₁₀V^vV^ivO₄₀ ^6– (k=(1,4±0,2)·10^{2 3}/·) pH=3 30%- CH₃COOH 20°C.

     

甘氨酸的杂多酚超分子化合物的合成及性质研究

首次合成了甘氨酸的Ｋｅｇｇｉｎ结构杂多酸超分子化合物（ＨＧｌｙ）３「ＰＷ１２Ｏ４０」．５Ｈ２Ｏ（ＨＧｌｙ）４「ＳｉＷ１２Ｏ４０」．４Ｈ２Ｏ,用元素分析,ＩＲ,ＵＶ,ＴＧ－ＤＴＡ,ＸＲＤ和ＮＭＲ等方法对标题化合物进行了表征,并讨论了它们的合成条件及结构特性。     

甘氨酸的杂多酸超分子化合物的合成及性质研究

首次合成了甘氨酸的Keggin结构杂多酸超分子化合物(HGly)3[PW12O40]·5H2O(HGly)4[SiW12O40]·4H2O,用元素分析,IR,UV,TG-DTA,XRD和NMR等方法对标题化合物进行了表征,并讨论了它们的合成条件及结构特性.     

银钨硼三元杂多配合物的合成、稀土多元渗及其导电性

用直接法合成了未见文献报道的具有Keggin结构的以Ag作为第二配位离子的钨硼杂多配合物,利用ICP,IR,XRD和XPS等对其结构进行了表征.以Gd作为渗入元素对其进行化学气相扩渗,借助IR,TG-DTA,XPS和XRD对配合物扩渗前后的结构及稳定性进行了对比研究.导电性的测试表明:室温下,扩渗后试样的电导率提高了约103倍,且热稳定性也有所提高,是一种受温度变化影响较小的导电材料,为制备可实用的导电材料提供了一条新途径.     

有机-无机复合杂多化合物的合成、结构及表征

利用常规水溶液法制备了三种基于饱和Keggin结构阴离子的有机-无机复合杂多化合物[Pr(pydc)(H2O)6]2H[PMo12O40]·4H2O(1)、[Nd(pydc)(H2O)6]2H[PMo12O40]·4H2O(2)和[Tb(pydc)(H2O)6]2H[PMo12O40]·4H2O(3)(pydc=2,6...     

Acrylic copolymer membranes with proton conductivity

This work presents the results of a study of acrylic copolymer films from aqueous and nonaqueous media. Films prepared from aqueous emulsions possess good physico-mechanical properties, are optically transparent, and are chemically resistant to concentrated solutions of acids and bases. They may also be safely heated to a temperature of 333 K. Charge transport occurs through ion exchange, and film conductivity is 1 × 10⁻³ S cm⁻¹ at 298 K and 50% humidity. Acrylic copolymer films prepared from nonaqueous media (toluene, benzene, isopropyl acetate) exhibit a conductivity of 5 × 10⁻³ S cm⁻¹ at 298 K and 50% humidity, and modifying agents can be added to increase conductivity to 5 × 10⁻² S cm⁻¹.     

Microheterometric titrations of large organic nitrogen-containing compounds and of heteropoly acids

Micro amounts of nitron, quinine, strychnine, papaverine, yohimbine, nicotine, atropine, morphine or phenanthroline were titrated heterometrically with silicotungstic, phosphotungstic or phosphomolybdic acids at pH 1 or 7. The heterometric curves and the compounds obtained were studied. The reverse titrations were also studied. Microheterometric determinations of large nitrogen-containing compounds and heteropoly acids are suggested.     

Pentadecatungstotrivanadodiphosphoric heteropoly acid with Dawson structure: Synthesis, conductivity and conductive mechanism

A general strategy in terms of degradating and ion-exchange synthesis was used to design pentadecatungstotrivanadodiphosphoric heteropoly acid H(9)P(2)W(15)V(3)O(62)·28H(2)O with Dawson structure and excellent conductivity. The product was characterized by ICP-MS, IR, UV, XRD, (31)P NMR, TG-DTA and electrochemical impedance spectroscopy (EIS). The results indicate that H(9)P(2)W(15)V(3)O(62)·28H(2)O possesses the Dawson structure. EIS measurements show a high conductivity (3.64 × 10(-2) S cm(-1) at 26 °C and 75% relative humidity), with an activation energy of 31.34 kJ mol(-1) for proton conduction. Its mechanism for proton conduction is the Vehicle mechanism.     

Synthesis and proton conductivity of anhydrous dendritic electrolytes

Water soluble PEG cored dendritic hexa-acid which comprises peripheral carboxylic acidic groups were prepared via nucleophilic substitution reactions. Novel anhydrous proton conducting electrolytes were prepared by incorporation of the heterocyclic protogenic solvent imidazole (Im) into PEG cored dendritic hexa acid, (PEG-HA), at several molar ratios of Im to-COOH units of PEG-HA. The complexation of PEG-HA and Im was illustrated by infrared spectroscopy (FT-IR). The materials are thermally stable up to 150 °C as evidenced by thermogravimetry analysis (TGA). Differential scanning calorimetry (DSC) results verified that the organic electrolytes are homogeneous and amorphous. The proton conductivities were characterized by means of AC impedance spectroscopy and a maximum conductivity of 1 × 10⁻³ S/cm was measured at 120 °C in the anhydrous state.      

Preparation and conductivity of tungstovanadogermanic heteropoly acid polyethylene glycol (PEG) hybrid material

In this work, the polyethylene glycol (PEG) hybrid material composited with tungstovanadogermanic heteropoly acid was prepared. Infrared (IR) spectrum revealed that the Keggin structure characteristic of the anion was present in PEG hybrid material. At room temperature (20°C), the conductivity of the sample is 4.07×10⁻³ S cm⁻¹. The results indicated that it is a new kind of excellent high-proton conductor. According to the experimental results, we proposed a possible mechanism of the proton conduction of the hybrid materials.     

Catalytic properties of heteropoly compounds in 1,3-butadiene oxidation with hydrogen peroxide

The homogeneous oxidation of 1,3-butadiene (BD) in H₂O₂-HPC-CH₃CN (HPC = heteropoly compound) solutions has been investigated. The route of the reaction depends on the nature of the metal capable of coordinating with active oxygen in the HPC. The products of radical BD oxidation (acrolein, 3-butene-1,2-diol, 2-butene-1,4-diol, furan) form in the presence of H_3+n PMo_{12 ? n} V _n O₄₀ (n = 1, 2) acids. 3,4-Epoxy-1-butene (EB) and acrolein + furan, which form in equal amounts in the presence of the (n-Bu₄N)₅PW₁₁O₃₉Fe(OH) salt, result, respectively, from the electrophilic addition of hydrogen peroxide to BD and from radical BD oxidation on iron-oxygen complexes in the HPC composition. The reaction carried out in the presence of (n-Bu₄N)₃{PO₄[WO(O₂)₂]₄}, (n-Bu₄N)₅Na_0.6H_1.4PW₁₁O₃₉, or (EMIm)₅NaHPW₁₁O₃₉ yields EB with high selectivity on the reacted BD basis (up to 97%) and H₂O₂ (about 100%). The formation and conversion of the phosphotungstate peroxo complexes PW _n O _m ^α? (n = 2, 3, 4) that are active in BD epoxidation have been investigated by ³¹PNMR spectroscopy. The role of the tetrabutylammonium and ethylmethylimidazolium cations in the formation of these complexes has been demonstrated.