Dawson结构磷钨钒杂多酸有机铵盐的合成及光谱研究

以偏钒酸铵、磷酸二氢钠和钨酸钠为原料,调节溶液的pH值为4,控制反应时间为10 h,合成了三钒取代的Dawson结构磷钨钒杂多酸,然后以化学反应计量的5倍量加入抗衡离子K+,制备了母体杂多酸盐K9P2W15V3O62·41H2O。在不断的搅拌下,将母体杂多酸盐的酸性溶液缓慢滴加到十六烷基三甲基溴化铵溶液中,合成了目标化合物磷钨钒杂多酸有机铵盐(C19H42N)6H3[P2W15V3O62]。经元素分析、红外光谱、X射线粉末衍射、差热-热重等手段进行了表征,表明目标化合物仍保持Dawson结构,为未见文献报道的杂多化合物。     

2∶18磷钼杂多酸(盐)在H_2O_2分解反应中的催化作用

研究了2:18磷钼杂多酸(盐)(Dawson结构)对H_2O_2分解反应的催化行为。实验结果表明,H_6(P_2Mo_(18)O_(62))和1:12磷钼杂多酸H_3(PMo_(12)O_(40))相同,对H_2O_2分解无活性,而其盐类(Fe~(3+)、Cu~(2+))则有很好的催化活性,但对H_2O_2分解的动力学行为不同于1:12磷钼杂多酸盐,符合二级动力学反应关系式。这可能和这两种结构中抗衡阳离子所处环境不同有关。杂多酸阴离子中引入V,部份取代钼后所得实验结果与1:12磷钼钒杂多酸完全相同,表明引入的钒离子在两种结构中不仅有相同的环境而且是催化剂的活性种。     

含不同碱金属杂多酸盐催化剂氧化还原性的ESR研究

用ＥＳＲ法研究了异丁醛一步氧化制甲基丙烯酸过程中所用杂多酸盐催化剂的氧化－还原特性，得到含不同碱金属杂多酸盐催化剂的还原－再氧化处理后的ＥＳＲ谱，讨论了不同碱金属对催化剂氧化还原特性的影响，比较了催化剂中过渡金属离子Ｃｕ，Ｖ，Ｍｏ的氧还原能力，分析了Ｃｕ＾＋易氧化性能对催化反应速度的影响。     

A novel composite polymer electrolyte containing room-temperature ionic liquids and heteropolyacids for dye-sensitized solar cells

A novel composite polymeric gel comprising room-temperature ionic liquids (1-butyl-3-methyl-imidazolium-hexafluorophosphate, BMImPF₆) and heteropolyacids (phosphotungstic acid, PWA) in poly(2-hydroxyethyl methacrylate) matrix was successfully prepared and employed as a quasi-solid state electrolyte in dye-sensitized solar cells (DSSCs). These composite polymer electrolytes offered specific benefits over the ionic liquids and heteropolyacids, which effectively enhanced the ionic conductivity of the composite polymer electrolyte. Unsealed devices employing the composite polymer electrolyte with the 3% content of PWA achieved the solar to electrical energy conversion efficiency of 1.68% under irradiation of 50 mW cm⁻² light intensity, increasing by a factor of more than three compared to a DSSC with the blank BMImPF₆-based polymer electrolyte without PWA. It is expected that these composite polymer electrolytes are an attractive alternative to previously reported hole transporting materials for the fabrication of the long-term stable quasi-solid state or solid state DSSCs.     

Phosphomolybdic acid-supported silica gel as efficient and cost-effective solid acid for the benzylation of indoles with benzylic alcohols

Indoles undergo smooth alkylation with benzylic alcohols on the surface of 10 mol% of phosphomolybdic acid supported on silica gel under mild conditions to produce C-3 benzylated-indoles in high yields and with high selectivity. This method offers significant advantages such as high conversions, short reaction times, mild reaction conditions, cleaner reaction profiles, high selectivity and low cost of the heterogeneous catalyst.     

H<Subscript>6</Subscript>P<Subscript>2</Subscript>W<Subscript>18</Subscript>O<Subscript>62</Subscript>: A green and reusable catalyst for the synthesis of 3,3-diaryloxindole derivatives in water

An efficient and improved procedure for the synthesis of oxindoles derivatives is developed via the electrophilic substitution reaction of indoles with various isatins in the presence of a Wells–Dawson tungsten heteropolyacid in water. Correspondence: Yaghoub Sarrafi, Department of Chemistry, University of Mazandaran, Babolsar, Iran.     

Chemical Immobilization of Heteropolyacid Catalyst on Inorganic Mesoporous Material for use as an Oxidation Catalyst

Recent progress on the chemical immobilization of heteropolyacid (HPA) catalyst on inorganic mesoporous material is reported in this review. Mesostructured cellular foam silica, mesoporous carbon, and nitrogen-containing mesoporous carbon were used as supporting materials. The mesoporous materials were modified to have a positive charge, and thus, to provide sites for the immobilization of HPA catalyst. By taking advantage of the overall negative charge of heteropolyanion, the HPA catalyst was chemically immobilized on the surface-modified mesoporous material as a charge-compensating component. Characterization results showed that the HPA catalyst was finely and molecularly dispersed on the surface of mesoporous material via strong chemical immobilization, and that the pore structure of mesoporous material was still maintained even after the immobilization of HPA catalyst. The supported HPA catalysts were applied to the model vapor-phase ethanol conversion, 2-propanol conversion, and methacrolein oxidation reactions. The supported HPA catalyst showed a better oxidation catalytic activity than the unsupported HPA catalyst in the model reactions. The enhanced oxidation catalytic performance of the supported HPA catalyst was attributed to the finely dispersed HPA catalyst, which was chemically immobilized on the positive site of mesoporous material by sacrificing its proton (Brönsted acid site). The HPA catalyst chemically immobilized on mesoporous material served as an excellent oxidation catalyst.     

Sulfonated poly(4-vinylpyridine) heteropolyacid salts:A reusable green solid catalyst for Mannich reaction

Sulfonated poly（4-vinylpyridine） heteropolyacid salts acted as a heterogeneous catalyst to effectively catalyze the one-pot synthesis of β-amino carbonyl compounds via the Mannich reaction between aromatic aldehydes, aromatic ketone, and aromatic amines. In addition, the catalyst could be easily recovered by the filtration and reused six times without significant loss of catalytic activity.     

几种焦磷杂多酸盐无机离子交换剂的制备及其对Cs＋的吸附性能

以焦磷酸钾、钼酸钠、氯化铁、氧氯化锆等为原材料，制备了焦磷钼酸锆（ZMPP）、焦磷氧酸锆（ZOPP）、焦磷钼酸铁（FMPP）3种焦磷杂酸盐无机离子交换剂，采用XRF，XRD，FT-IR，SEM对合成样品进行了表征，测定了合成样品对Cs＋的吸附性能，研究了合成样品的耐酸性。结果表明：ZMPP，ZOPP，FMPP为组成不定的无定形态物质，其中ZMPP，ZOPP呈箔状，FMPP呈凝胶状；ZMPP，ZOPP，FMPP三者对Cs＋均具有较好的吸附性，实验条件下，以常温合成的ZMPP-25，FMPP吸附性较好，两者的吸附量可达2．38 mmol／g和2．36 mmol／g；少量Mo元素的存在，对ZMPP-25，ZOPP吸附Cs＋的性能影响较大，前者较后者提高了约50％；3种交换剂的耐酸性从强到弱的顺序为ZMPP-25〉ZOPP〉FMPP。     

固体高质子导体钨钒锗酸的制备及导电性能研究

本文首次采用分步酸分，分步加入原料方法制备出新型固体高质子导体钨钒锗酸 Ｈ５ＧｅＷ１１ＶＯ４０．２２Ｈ２Ｏ。