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合成了一系列Br(o)nsted酸性离子液体并将其应用在醛醇缩合反应中.醛醇缩合产物由于极好的溶剂性质等被广泛用作溶剂和试剂.离子液体[BSmim][OTf]在甲醛和乙二醇缩合生成1,3-二氧五环的反应中表现出了极好的催化活性,甲醛转化率和主产物1,3-二氧五环选择性分别可以达到96.1%和92.4%.对影响离子液体催化性能的因素进行了探索,并对催化反应中的离子液体的用量、反应温度、反应时间以及反应物料比进行了考察.通过Hammett酸度函数法测定了所用到离子液体的酸性,结果表明离子液体酸性与其在缩合反应中的催化活性顺序完全一致,酸性越强催化性能越好.结合实验给出了离子液体[BSmim][OTf]催化甲醛和乙二醇缩合反应的可能的反应机理.该催化剂体系具有良好的催化性能,反应可以在较温和的条件下进行,实现了高活性和高选择性的目标,产物易分离,催化剂重复使用7次,其催化活性基本不变.并将该Br(o)nsted酸性离子液体进一步应用到其他醛(酮)醇缩合反应中. 相似文献
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考察了各种不同介质中,芳醛、丙二腈和苯硫酚为原料的一锅反应,发现在离子液体1-正丁基-3-甲基咪唑四氟硼酸盐([bmim]BF4)介质中,反应能够在较短时间内高产率地生成2-氨基-4-苯基-6-(苯基硫基)-3,5-二氰基吡啶衍生物,且没有1,4-二氢吡啶副产物的生成.该方法具有反应条件温和、产率高、选择性好和环境友好等优点,且离子液体容易回收,可循环使用. 相似文献
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利用吡啶和正溴丁烷合成离子液体中间体[BPy]Br,再由[BPy]Br和NaBF4合成了离子液体[BPy]BF4,对其进行了FT-IR,1 H NMR和TG-DTA表征.将合成的离子液体作为溶剂,磷钨酸为催化剂,催化β-萘甲醚(MM)和乙酸酐(AA)的乙酰化反应.结果表明,该反应的主要产物是2-甲氧基-1-萘乙酮.反应的较佳工艺条件为:β-萘甲醚0.01mol,β-萘甲醚与乙酸酐的摩尔比为1∶1.5,磷钨酸0.05g,100℃下反应4h,反应物β-萘甲醚的转化率达到57.04%,最高选择性可达99.04%.通过萃取分离实现回收磷钨酸-离子液体的催化体系,并可循环使用5次,催化活性无下降. 相似文献
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《分子催化》2017,(4)
合成了一系列Brnsted酸性离子液体并将其应用在醛醇缩合反应中.醛醇缩合产物由于极好的溶剂性质等被广泛用作溶剂和试剂.离子液体[BSmim][OTf]在甲醛和乙二醇缩合生成1,3-二氧五环的反应中表现出了极好的催化活性,甲醛转化率和主产物1,3-二氧五环选择性分别可以达到96.1%和92.4%.对影响离子液体催化性能的因素进行了探索,并对催化反应中的离子液体的用量、反应温度、反应时间以及反应物料比进行了考察.通过Hammett酸度函数法测定了所用到离子液体的酸性,结果表明离子液体酸性与其在缩合反应中的催化活性顺序完全一致,酸性越强催化性能越好.结合实验给出了离子液体[BSmim][OTf]催化甲醛和乙二醇缩合反应的可能的反应机理.该催化剂体系具有良好的催化性能,反应可以在较温和的条件下进行,实现了高活性和高选择性的目标,产物易分离,催化剂重复使用7次,其催化活性基本不变.并将该Brnsted酸性离子液体进一步应用到其他醛(酮)醇缩合反应中. 相似文献
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A low barrier in the reaction pathway between the double Rydberg isomer of OH(3) (-) and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron spectroscopy than the well known double Rydberg anion (DRA), tetrahedral NH(4) (-). Electron propagator calculations of vertical electron detachment energies (VEDEs) and isosurface plots of the electron localization function disclose that the transition state's electronic structure more closely resembles that of the DRA than that of the hydride-water complex. Possible stabilization of the OH(3) (-) DRA through hydrogen bonding or ion-dipole interactions is examined through calculations on O(2)H(5) (-) species. Three O(2)H(5) (-) minima with H(-)(H(2)O)(2), hydrogen-bridged, and DRA-molecule structures resemble previously discovered N(2)H(7) (-) species and have well separated VEDEs that may be observable in anion photoelectron spectra. 相似文献
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Summary Dichlorobis(methylsalicylato)titanium(IV) reacts with potassium or amine salts of dialkyl or diaryl dithiocarbamates in 11 and 12 molar ratios in anhydrous benzene (room temperature) or in boiling CH2Cl2 to yield mixed ligand complexes: (AcOC6H4O)2 Ti(S2CNR2)Cl (1) and (AcOC6H4O)2 Ti(S2CNR2)2 (2), R=Et, n-Pr, n-Bu, cyclo-C4H8 and cyclo-C5H10. These compounds are moisture sensitive and highly soluble in polar solvents. Molecular weight measurement in conjunction with i.r.,1H and13C n.m.r. spectral studies suggest coordination number 7 and 8 around titanium(IV) in (1) and (2) respectively. 相似文献
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Pure, highly explosive CF(3)C(O)OOC(O)CF(3) is prepared for the first time by low-temperature reaction between CF(3)C(O)Cl and Na(2)O(2). At room temperature CF(3)C(O)OOC(O)CF(3) is stable for days in the liquid or gaseous state. The melting point is -37.5 degrees C, and the boiling point is extrapolated to 44 degrees C from the vapor pressure curve log p = -1875/T + 8.92 (p/mbar, T/K). Above room temperature the first-order unimolecular decay into C(2)F(6) + CO(2) occurs with an activation energy of 129 kJ mol(-1). CF(3)C(O)OOC(O)CF(3) is a clean source for CF(3) radicals as demonstrated by matrix-isolation experiments. The pure compound is characterized by NMR, vibrational, and UV spectroscopy. The geometric structure is determined by gas electron diffraction and quantum chemical calculations (HF, B3PW91, B3LYP, and MP2 with 6-31G basis sets). The molecule possesses syn-syn conformation (both C=O bonds synperiplanar to the O-O bond) with O-O = 1.426(10) A and dihedral angle phi(C-O-O-C) = 86.5(32) degrees. The density functional calculations reproduce the experimental structure very well. 相似文献
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