一种温和高效的钯催化乙炔的环三聚

乙炔是石油化工的重要产品之一,乙炔分子中存在高活性的π电子体系,具有很高的反应活性。许多催化体系包括过渡金属催化剂、非金属催化剂等可以催化活泼的乙炔发生环三聚反应,得到重要的化工原料苯。作者首次利用氯化钯作为催化剂催化乙炔环三聚,在很温和的条件下高效率地实现了这一反应。     

Preparation of Uniform Ni-B Amorphous Alloy Catalyst on CNTs and its Performance for Acetylene Selective Hydrogenation

Carbon nanotubes (CNTs) are severely bundled and essentially insoluble in solvent. These properties are generally considered as a significant barrier toward the practical uses of CNTs. Therefore, the functionalization and solubilization of CNTs have recei…     

聚苯乙炔的伏安特性

聚苯乙炔的伏安特性周淑琴（中国科学院化学研究所北京１０００８０）关键词聚苯乙炔，伏 安特性，欧姆电导，空间电荷限制电流，高斯分布陷阱能级，陷阱态密度聚苯乙炔（ＰＰＡ）是一种具有π电子的共轭高分子聚合物，它的光电导特性引起了同行的兴趣［１］．目前高分...     

Theoretical Study of the Products of Acetylene Addition to HgCl2

The ab initio MP2 method is used with the LANL2DZ basis to calculate the mercury chloride ,-complex with two acetylene molecules (1) and various isomeric forms of mercury di()-vinyl chloride -complexes (2): cis-cis (2A), cis-trans (2B), and trans-trans (2C). The ,-complex is the most stable form of all those considered; the difference between 1 and 2A is 24.9 kcal/mole. A relation between the total energies (kcal/mole) for isomeric forms 2 is established to be 2A (0) < 2B (0.98) < 2C (1.58). Complex 1 is shown to be transformed into 2A via the intermediate formation of 3, which is a hybrid form of the complex (,-complex of mercury chloride with two acetylene molecules). The structures of the transition states for the transformations of 1 into 3 (structure 4) and of 3 into 2A (structure 5) and the corresponding transition activation energies are determined. The interaction of 2A, 2B, and 2C with the Cl^- anion as a model nucleophile is considered. It is shown that the resulting anions (6A, 6B, 6C) have a planar structure with the relative stability increasing in the series 6A<6B<6C.     

CATALYTIC ACTIVITY OF Pd-Sn COMPLEX CARBONYLATION OF ACETYLENE

The influence of different concentration of HO, SnCl2, Cl- and n-BuOH on the carbonylation of acetylene has been studied. The results show that the yield of n- butyl propionate increases with the increase of HC1 concentration and the catalytic activity is depressed when Cl" concentration increases. However, the stability of catalytic complex is promoted by Cl-. The key to the carbonylation of acetylene lies in the addition of SnCl2, which promotes the formation of the complex of C2H2, CO with catalyst and plays an important role in the hydrogen removal from n-BuOH. The hydrogen removed from n BuOH is the hydrogen source of this reaction. Meanwhile, the principle of the effect of HCl, Cl- and SnCl2 on reaction has been discussed. The reaction model has also been proposed.     

An infrared spectroscopic study of changes in unsaturation resulting from irradiation of isotropic and uniaxially oriented polyethylene films in the presence of acetylene

Interchain bridges of unsaturated double bonds have been proposed to form in amorphous regions, when polyethylene is irradiated in the presence of acetylene. We have corroborated the formation of these bridges by infrared spectroscopic studies. The double bonds are composed mainly of trans-olefin and vinyl end groups, formed as a result of competing radical-radical termination and hydrogen atom abstraction reactions. The hydrogen atom abstraction reaction becomes insignificant in uniaxially oriented high-density polyethylene having a draw ratio of 7.5, because of the alignment and positioning of the initiating radical pairs. During in vacuo irradiation and annealing only in-chain trans-olefins are usually formed. © 1994 John Wiley & Sons, Inc.     

The X-ray structure of Os(CS)(PhCCPh)(PPh3)2, a complex containing a four-electron donor acetylene ligand

Os(CS)(PhC?CPh)(PPh₃)₂ is formed by the treatment of Os(CS)(CO)(PPh₃)₃ with diphenylacetylene and is an example of a complex containing a four-electron donor acetylene ligand. Os(CS)(PhC?CPh)(PPh₃)₂ crystallizes in the monoclinic space group P2₁/n with the cell dimensions a = 9.028(5), b = 25.256(2) and c = 19.22(2) Å with β = 103.8(7)°, V = 4260 ų, Z = 4 and d(calcd) = 1.461 g cm^?3 for mol.wt 937.09 g mol^?1. Diffraction data were collected with a Nonius CAD-4 diffractometer and refined to R = 4.05% and R_w = 4.19% for 1172 independent reflections. The structure can be described as a distorted trigonal bipyramid with the CS ligand occupying an axial position. The two cis-PPh₃ ligands are in equatorial sites with the acetylene occupying a position between the remaining axial and equatorial sites. The diphenylacetylene is symmetrically bound to the metal with an average Os? C distance of 2.04(3) Å. The Os? CS distance is unusually short at 1.79(2) Å.     

Hydrogen bonding in acetylene containing dichlorodiazaalkadienes

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