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61.
Various catalysts for the polymerization ot aromatic nitriles were investigated. It was found that Lewis acid-metal is a preferable catalyst system for the polymerization of aromatic nitriles, and the polymerization rate is about 10 times faster than Lewis acid alone. The polymerization rate of benzonitrile catalyzed by Lewis acid and different metals was measured, and the activity of metals was in the following decreasing order ,magnesium, zinc, sodium, calcium. Furthermore, the polymerization of benzonitrile catalyzed by different Lewis acid and zinc was also investigated. 相似文献
62.
Sanjeev K. Garg 《Tetrahedron letters》2005,46(10):1721-1724
Copper(II) tetrafluoroborate has been found to be a new and highly efficient catalyst for Michael addition of thiols to α,β-unsaturated carbonyl compounds under solvent-free conditions and in H2O at room temperature. The reactions are very fast and are completed in 2 min to 1 h affording high yields. The rate of thiol addition was dependent on the steric hindrance at the β-carbon of the α,β-unsaturated carbonyl substrate. In the case of chalcones, the reactions are best carried out in MeOH as solvent. 相似文献
63.
Treatment of an acetonitrile solution of CuI with 1, 7‐dithia‐18‐crown‐6 (1, 7‐DT18C6) at 100°C affords the coordination polymer 1[(CuI)2(1, 7‐DT18C6)2] ( 1 ) in which 1, 7‐DT18C6 ligands bridge (CuI)2 rings into double chains. 1D polymers of the type 1[M{(Cu3I4)(1, 7‐DT18C6)}] (M = K, 2 ; M = Cs, 3 ) can be isolated under similar conditions in the presence of respectively KI and CsI. Both contain bridging heptacyclic [Cu6I8]2— units but crystallise in different space groups, namely P1 and C2/m. The cesium cation of 3 is markedly displaced from the best plane through the thiacrown ether donor atoms. Reaction of 1, 7‐DT18C6 with CuSCN in the presence of NaSCN yields 2[{Na(CH3CN)2} {(CuSCN)2(1, 7‐DT18C6)}][Cu(SCN)2] ( 4 ), in which 1[(CuSCN)2] double chains are linked through macrocycles into sheets. Infinite 1[{Cu(SCN)2}—] chains compensate the charge of the Na+ cations. Complex 1 can imbibe 0.90 mol CsNO3 per mol of 1, 7‐DT18C6 pairs. 相似文献
64.
Zusammenfassung Das -Isomer des Antimontribenzoats kristallisiert rhomboedrisch (hexagonale Aufstellung) in der Raumgruppe R3 mita=1944.0 pm,c=422.3 pm undZ=3. Die Moleküle sind parallel zu 001 gestapelt. Sb hat gegenüber O die Koordinationszahl 3+3 (Sb-O: 208 bzw. 256 pm).
Antimonytribenzoate
Summary The isomer of (C6H5CO2)3Sb crystallizes rhombohedrally (hexagonal axes) in the space group R3 witha=1944.0 pm,c=422.3 pm, andZ=3. The molecules are stacked parallel to 001; Sb has a coordination number of 3+3 (Sb-O: 208 and 256 pm, resp.).相似文献
65.
The novel coordination polymer [Pr(BYBA)3(H2O)2]·[Pr(BYBA)3(H2O)] (BYBAH = 2-benzoylbenzoic acid) was yielded by hydrothermal synthesis, determined by single-crystal X-ray diffraction, and characterized by FT-IR and UV-Vis spectra. The crystal crystallizes in the triclinic system, space group P with a = 9.112(3), b = 14.644(5), c = 27.076(11) (A), α = 84.223(3), β = 87.816(4), γ = 88.902(4)o, V = 3592(2) (A)3, C84H60O21Pr2, Mr = 1687.14, Z = 2, F(000) = 1700, Dc = 1.560 g/cm3, μ = 1.419 mm-1, the final R = 0.0485 and wR = 0.1258 for 13035 observed reflections with I>2((I). The compound contains two different building units, [Pr2(BYBA)6(H2O)4] and [Pr2(BYBA)6(H2O)2]. It is noticeable that [Pr2(BYBA)6(H2O)4] is an isolated binuclear building block, in which the Pr3 ion centers are both located in an eight-coordinated environment. However, in [Pr2(BYBA)6(H2O)2] the Pr3 ion centers are located in a nine-coordinated environment and connected by BYBA ligands to form 1D chains. 相似文献
66.
CuO/γ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuO/γ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuO/γ-Al2O3 catalyst prepared via plasma was much higher than that of the CuO/γ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment. 相似文献
67.
氧化铈对Pd/Al2O3表面上CO氧化性能的影响 总被引:7,自引:0,他引:7
采用TPD-MS及TPSR-MS技术研究了添加CeO2对Pd/Al2O3催化剂上CO脱附、表面反应及表面氧脱附等性能的影响,考察了不同含氧量的气氛下CO的氧化活性,结果表明,Pd-Ce间的相互作用有利于各自原子上表面氧的吸脱附及CO的表面反应,并发现CO2脱附量大小及峰温次序与对CO的催化氧化活性有一致的对应关系。 相似文献
68.
Ram C. Besra 《Tetrahedron letters》2005,46(37):6213-6217
Copper(II) tetrafluoroborate hydrate is a new and extremely efficient catalyst for 1,3-dithiolane/dithiane formation from aromatic, heteroaromatic and aliphatic aldehydes and cyclic saturated ketones in 1-5 min under solvent-free conditions at room temperature. The reaction is compatible with other functionalities such as ether, ester, hydroxyl, halide, nitro and cyano groups and exhibits excellent chemoselectivity. α,β-Unsaturated aldehydes/ketones lead to selective formation of 1,3-dithiolanes instead of Michael addition products. For substrates bearing an aldehyde and a ketone carbonyl group, chemoselective dithiolane formation takes place with the aldehyde. 相似文献
69.
Solid state M-4-Me-BP compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn, Pb and 4-Me-BP is 4-methylbenzylidenepyruvate, have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterise and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes. 相似文献
70.
共轭二烯烃的聚合是配位阴离子聚合,双金属配合物是聚合的活性中心,控制单体的构象是控制聚合物结构的关键。单体在低值配位场稳定化能(LFSE)过渡金属离子,如Co~(2+)、Ti~(3+)上螯合,螯合单体具有顺式构象,所得聚合物具有顺1,4结构;在中等LFSE的过渡金属离子,如V~(3+)、Cr~(3+)上配位,配位单体具有反式构象,所得聚合物具有反1,4结构或是1,2聚合物;高LFSE值过渡金属离子不易控制活性价态,双金属配合物不够稳定,所得聚合物分子量常较低,结构规整性也常不够理想。 相似文献