丁二烯催化环化三聚中多金属的协同效应

研究了第二过渡金属化合物对ＴｉＣｌ４／ＡｌｅＴ１．４６ｃＬ１．５４催化丁二烯环化三聚的多金属协同效应。结果表明，极少量的第二过渡金属化合物，如Ｃｒ，（ａｃａｃ）３，Ｍｎ（ａｃａｃ）３，ＮｉＣｌ２，ＺｒＣｌ４等加入ＴｉＣｌ４／ＡｌＥｔ１．４６Ｃｌ１．５４体系后不同程度地提高了丁二烯环化三聚的选择性，并改变了体系的最大速率和催化剂效率。     

Mechanism of Butadiene Polymerization on Cobalt-Containing Catalyst

Based on experimental results and reference data, the main elementary stages of butadiene polymerization on a cobalt-containing catalyst were determined and a mathematical model of the polymerization was developed. The following characteristics of the process were studied using this model: number-average, weight-average, and sedimentation-average degrees of polymerization and branching factor.     

Cyclodimerization of vinylpyridines

When isomeric 2- and 4-vinylpyridines, as well as 2-methyl-5-vinylpyridine, are heated in polyphosphoric or acetic acid, they undergo dimerization, which proceeds via a 1,4-cycloaddition scheme to give pyridyl-substituted 5,6,7,8-tetrahydroquinclines or isoquinolines. Quantum-chemical calculations with the use of the concepts of molecular orbital perturbation theory make it possible to predict the regiospecificity of the reaction. The regiospecific cross cycloaddition of 4-vinylpyridine to 2-methyl-5-vinylpyridine was proposed theoretically and proven experimentally.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1248–1254, September, 1980.     

丁二烯在Ba,Cs,Cl促进的Ag/α-Al2O3催化剂上的环氧化反应及稳定性研究

在Ba、Cs、C l促进的Ag/α-A l2O3催化剂上,考察了丁二烯的环氧化反应,获得较高的丁二烯转化率和乙烯基环氧乙烷选择性.在未添加卤代烃致稳剂条件下,催化剂短期稳定性超过140 h.并对反应前后的催化剂进行了XRD、TEM、XPS等晶相和表面分析.XRD结果表明催化剂经短期稳定性试验后,银的平均粒径变化不大,但TEM分析表明在银催化剂的局部有银颗粒的板结;而XPS结果表明催化剂表面C l有流失,Cs有富集.Cs-Ag的相互作用有可能促进吸附于Cs-A l活性位的氧物种插入吸附于Ag上的丁二烯.     

丁烯在Ba，Cs，Cl促进的Ag／α-Al2O3催化剂上的环氧化反应及稳定性研究

在Ba、Cs、Cl促进的Ag／α—Al2O3，催化剂上，考察了丁二烯的环氧化反应，获得较高的丁二烯转化率和乙烯基环氧乙烷选择性．在未添加卤代烃致稳剂条件下，催化剂短期稳定性超过140h．并对反应前后的催化剂进行了XRD、TEM、XPS等晶相和表面分析．XRD结果表明催化剂经短期稳定性试验后，银的平均粒径变化不大，但TEM分析表明在银催化剂的局部有银颗粒的板结；而XPS结果表明催化剂表面Cl有流失，Cs有富集．Cs-Ag的相互作用有可能促进吸附于Cs—Al活性位的氧物种插入吸附于Ag上的丁二烯．     

Cyclodimerization of a citral dienamine

The dienamine (a mixture of isomers) obtained from citral and diethylamine is converted to a mixture of citral anhydro cyclodimers by the action of weak proton-donor agents. The principal reaction product corresponds to [4 + 2]-cycloaddition of 1-diethylamino-7-methyl-3-methylene-1,6-octadiene (the minor component in the starting dienamine) to the enimmonium form of the protonated dienamine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1189–1192, May, 1991.     

Thermal Decomposition Kinetics and Mechanism of Low-temperature Hydrogenated Acrylonitrile Butadiene Rubber Composites with Sodium Methacrylate

Thermal decomposition processes and mechanism of low-temperature grade hydrogenated acrylonitrile butadiene rubber(LTG-HNBR) composites with sodium methacrylate(NaMAA) were investigated by thermogravimetric analysis(TGA) and Fourier transform infrared spectroscopy(FTIR) coupling technology in this article. The results of TGA demonstrate that the addition of NaMAA can enhance the thermal decomposition temperature of the rubber. Moreover, it was found that the composites spent more activation energies to decompose than pure rubber by the calculations of multiply heating rate method. Time-resolved FTIR spectra show that NaMAA affects the initial decomposition of the composites. But in the following process, the composites maintained a similar behavior to the matrix. During the decomposition, PNaMAA nanostructures, in-situ generated by NaMAA, helped reduce the diffusion speed of decomposition products and thus improved the thermal stability of the composites. We believe that these findings can provide some guides to direct the applications of LTG-HNBR composites with unsaturated metal methacrylates.     

加氢脱硫催化剂与反应机理的研究进展

本文综述了加氢脱硫反应机理、加氢脱硫催化剂的研究与开发的最新进展.对常用的模型化合物的加氢脱硫机理及其影响因素、催化剂的结构、活性相与助剂、载体以及添加剂的性互作用与影响进行了讨论.     

Cyclodimerization of phenyliodoacetylene with elemental tellurium: New pathway to 1.3-ditellurofulvenes

Thermal reaction between PhCCI and powdered Te afforded a mixture of (E)-4-iodo-2-(iodo(phenyl)-5-phenyl-1,3-ditellurofulvene (1) and (Z)-4-iodo-2-(iodo(phenyl)-5-phenyl-1-(diiodo),3-ditellurofulvene (2), which was subsequently reduced to (Z)-4-iodo-2-(iodo(phenyl)-5-phenyl-1,3-ditellurofulvene (3). Formation of 1 and 3 as the thermodynamically most stable products has been rationalized using density functional theory (DFT) calculations. Molecular structures of 1-3 were established crystallographically. In the solid state the coordination sphere of both tellurium atoms in 2 is extended by weak intermolecular Te?π interactions with the solvate molecule of toluene which completes the pseudo-trigonal bipyramidal coordination geometry around each Te atom and assembles 2 into the chains along the crystallographic c-axis.     

氨合成催化剂及其催化反应机理研究进展

本文综述了氨合成这一最重要的工业多相催化过程80 多年来的研究进展。介绍了氨合成熔铁催化剂、氨合成钌催化剂的发展以及对氨合成催化反应机理的不同看法。     

Hydrooligomerization of Butadiene with Nickel Complex Catalyst

Abstract

Oligomerization of butadiene with the catalyst system of nickel(II)chloride, electron donor, and lithium aluminum hydride or sodium borohydride has been studied. Most oligomers obtained with this catalyst were linear, and dihydrogenated dimers, trimers, and tetramers. They were n-octa-1,6-diene, n-octa-1,7-diene, n-dodeca-1,6,10-triene, and n-hexadeca-1,6,10,14-tetraene, which were identified by means of infrared, nuclear magnetic resonance, and mass spectrometry. Yields of each oligomer were strongly affected by the nature of the electron donors used. The hydrogen required for the formation of the hydrooligomers was assumed to originate from the lithium aluminum hydride or sodium borohydride used as a reducing agent. A proposed mechanism for the hydrooligomerization is that butadiene is oligomerized on the nickel atom, and the produced oligoolefins, bonded to the nickel by two terminal π-allylic bonds, are dihydrogenated to linear hydrooligomers.     

The Mechanism of Diene Polymerisation by Organolanthanide Catalysts Deduced from Microwave Experiments

Summary: Isoprene polymerisation performed under microwave irradiation with [Nd(BH₄)₃(THF)₃]/Mg(Bu)₂ and [Nd(BH₄)₃(THF)₃]/Al(Et)₃ showed an enhancement in reactivity, with selectivity being only slightly modified. An explanation of the observed effect is proposed based on our current knowledge of the catalytic mechanism and by considering the alkylated complex as an ion pair. An analogy is proposed with the pseudoanionic polymerisation of oxygenated monomers. Finally, depolymerisation is observed under microwave irradiation at high temperature.

Postulated mechanism for the polymerisation of isoprene with [Nd(BH₄)₃(THF)₃]/Mg(Bu)₂.