Synthesis of coumarins by Pt-catalyzed hydroarylation of propiolic acids with phenols

Synthesis of coumarins from phenols and propiolic acids was examined by using a Pt catalyst such as PtCl₂/AgOTf, K₂PtCl₄/AgOTf, and K₂PtCl₄/AgOAc. Propiolic acid reacted even with less reactive phenols in trifluoroacetic acid to give coumarins and dihydrocoumarins. In the case of substituted propiolic acids, phenylpropiolic acid and 2-octynoic acid, the reactions proceeded selectively to afford coumarins in good to high yields.     

Electrochemical characterization of poly(vinylidenefluoride)-zinc triflate gel polymer electrolyte and its application in solid-state zinc batteries

Gel polymer electrolyte (GPE) films comprising of poly(vinylidenefluoride), propylene carbonate, ethylene carbonate and zinc trifluoromethane sulfonate are prepared and characterized. The composition of GPE is optimized to contain minimum liquid components with a maximum specific conductivity of 3.94×10⁻³ S cm⁻¹ at (25±1) °C. A detailed investigation on the properties such as ionic conductivity, transport number, electrochemical stability window, reversibility of Zn/Zn²⁺ couple and Zn/gel electrolyte interfacial stability have been carried out. The ionic conductivity follows a VTF behaviour with an activation energy of about 0.0014 eV. Cationic transport number varies from 0.51 at 25 °C to 0.18 at 70 °C. Several cells have been assembled with GPE as the electrolyte, zinc as the anode, γ-MnO₂ as the cathode and their charge–discharge behaviour followed. Capacity values of 105, 82, 64 and 37 mAh/g of MnO₂ have been achieved at 10, 50, 100 and 200 μA/cm² discharge current densities, respectively. The discharge capacity values are almost constant for about 55 cycles for all values of current densities. Cyclic voltammetric study of MnO₂ electrode in Zn/GPE/MnO₂ cell clearly shows intercalation/deintercalation of Zn²⁺.     

Diversification of shotgun process

Three protocols for shotgun process are put forth in which simultaneous multi-fold reactions occur exclusively to each other. The first one involves simple combination of selective and non-selective reactions. Even if the simple protocol fails to give rise to the high selectivity, satisfactory outcome can be achieved by kinetic control or adjustment of functional groups.     

基于MCM-41分子筛表面的镱离子印迹聚合物的制备及其性能

运用离子印迹技术,以3-氯丙基三乙氧基硅烷为锚定剂,将功能单体直链聚乙烯亚胺(PEI)接枝在MCM-41分子筛表面,选择镱离子作为模板离子,以环氧氯丙烷交联制备出基于MCM-41表面的镱离子印迹聚合物Yb(Ⅲ)-IIP-PEI/MCM-41,并以同样的方法制备非离子印迹聚合物(NIP-PEI/MCM-41)。 利用傅里叶变换红外光谱仪和扫描电子显微镜等技术手段对Yb³⁺印迹聚合物进行表征,采用静态吸附法确定了Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺的最佳吸附条件及选择性吸附性能。 结果表明,Yb(Ⅲ)-IIP-PEI/MCM-41和NIP-PEI/MCM-41的最大吸附量分别为229.93和99.27 mg/g;印迹材料对Yb³⁺的吸附符合Langmuir模型;吸附平衡在40 min的时候基本可以达到,可以利用准二级动力学模型来描述其吸附过程;Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺具有较强的选择性,同时也具有很好的重复使用性能。 成功地将MCM-41和离子印迹聚合物的优点结合起来,制备出一种对稀土Yb离子既有高吸附量又有高选择性的吸附材料,为进一步将其应用在处理实际废水,分离回收低浓度稀土废水中的稀土元素等方面打下了基础。     

P-507回流萃取法富集镥的研究——Ⅰ.P-507萃取分离镱镥混合稀土的性能

本文研究了2-乙基己基膦酸单2-乙基己基酯(P-507)在盐酸和硝酸体系中萃取镱镥混合稀土的性能。说明P-507在硝酸体系中的萃取分离系数较其在盐酸体系中高,而在盐酸体系中有更高的反萃效率。与二(2-乙基己基)磷酸(P-204)相比,P-507具有萃取酸度低、易反萃和不易乳化的优点。我们还确定了回流萃取法分离镥镱的基本参数,表明P-507是一种新型的分离重稀土的良好萃取剂。     

Sc(OTf)3-catalyzed alkylation of indoles with propargyl alcohols: an expeditious synthesis of 3-substituted indoles

Indoles undergo smooth alkylation with propargylic alcohols in the presence of 10 mol % of scandium triflate under mild conditions to produce 3-propargylated indoles in excellent yields with high selectivity.     

Yb(OTf)3-catalyzed cyclization of an N-silylenamine with 2-methylene-1,3-cyclohexanedione to afford a 7,8-dihydroquinolin-5(6H)-one derivative and its application to the one-pot conversion to a 2,3,5-trisubstituted quinoline derivative

A catalytic amount of ytterbium triflate (Yb(OTf)₃) promotes the cyclization of an N-silylenamine with in situ generated 2-methylene-1,3-cyclohexanedione and 2-methylenecyclohexanone to produce the corresponding 2,3-disubstituted 7,8-dihydroquinolin-5-one and 5,6,7,8-tetrahydroquinolin-5-one in moderate to good yields. A one-pot conversion of 7,8-dihydroquinolin-5-one to the quinoline derivative also proceeded in good yield.     

电极条件对硫酸介质中电解还原提纯镱过程的影响

研究了以钌铱钛合金网和汞分别为阳、阴电极, 在无气氛保护条件下, 采用电解还原方法从铥、镱、镥硫酸盐溶液中分离提纯镱的过程. 讨论了在8 V恒电压时的电极间距、位置, 以及阴、阳极表面积对电解过程中的电流、还原率影响. 优化了电解还原过程, YbSO4产品的纯度稳定达到99.5%以上, 一次收率可达80%;提镱后母液中的铥和镥被富集4倍以上, 其中Lu含量高于50%, 十分有利于后续铥/镥分离.     

Reactivity of ytterbium in liquid ammonia

A solution of metallic ytterbium in liquid ammonia reacts readily with various carbonyl complexes of metals to form the corresponding lanthanide carbonylmetallates. The reaction of an excess of Yb in liquid NH₃ with [CpFe(CO)₂]₂ gave (THF)₄Yb[Fe(CO)₂Cp]₂ in 42% yield. It was suggested that the resulting complex contains two equivalent Yb−Fe bonds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1883–1885, October, 1997.     

Bismuth triflate catalyzed Claisen rearrangement of allyl naphthyl ethers

Bismuth triflate was found to be an efficient catalyst for the Claisen rearrangement of allyl naphthyl ethers. The reaction proceeds smoothly with a catalytic amount of bismuth triflate (20 mol %) to afford the corresponding ortho-allyl naphthol in moderate to good yields in most cases.