Composition catalysts of ethylbenzene oxidation based on bis(acetylacetonato)nickel(ii) and phase transfer catalysts as ligands 1. Macrocyclic polyethers

The addition of the macrocyclic polyether 18-Crown-6 (18C6) increases the selectivity of oxidation of ethylbenzene to -phenylethylhydroperoxide (PEH) in the presence of Ni(acac)₂. The initial oxidation rate, selectivity and degree of conversion of ethylbenzene to PEH are greater than those catalyzed by Ni(acac)₂ only. The efficiency of the macrocyclic ligand as an activator of Ni(acac)₂ exceeds that of monodentate donor ligands. The high selectivity of the process is due to both the primary Ni(acac)₂ · 18C6 complexes and the products of their transformation in the course of oxidation. The mechanism of ethylbenzene oxidation catalyzed by Ni(acac)₂ · 18C6 complexes is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1406–1411, August, 1994.     

Asymmetric zirconocene precursors for catalysis of propylene polymerization

Racemic isopropylidene (1-η⁵-cyclopentadienyl)(1-η⁵-indenyl) dichlorozirconium and the 3-methylindenyl derivative have been synthesized and characterized. These precursors activated with methylaluminoxane produce poly(propylene) with hemiisotactic microstructures. © 1994 John Wiley & Sons, Inc.     

Development of a Novel Approach to Formation of a Pyrrole Ring: Synthesis of 2,3,5-Substituted 1-[2-(Vinyloxy)ethyl]pyrroles

Reaction of 2-(vinyloxy)ethylisothiocyanate with unsaturated carbanions generated in situ from propargyl ethers and amines when treated with superbases, after S-alkylation and cyclization of the adducts in the presence of CuBr, leads to the previously unknown 2,3,5-substituted 1-[2-(vinyloxy)ethyl]pyrroles.     

Three-component,one-pot synthesis of 3,4-dihydropyrimidin-2-(1<Emphasis Type="Italic">H</Emphasis>)-ones catalyzed by bromodimethylsulfonium bromide

An efficient synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives by one-pot three-component condensation reaction between an alkyl or aryl aldehyde, a 1,3-dicarbonyl compound, and urea or thiourea in the presence of catalytic amount of bromodimethylsulfonium bromide has been developed. The condensation product was obtained in excellent yields in refluxing ethanol and easily separated from the reaction mixture and purified.     

固体超强碱氧化钙催化制备生物柴油及其精制工艺

 以麻风果油为原料,研究了固体超强碱氧化钙在生物柴油制备工艺中的催化性能,考察了催化剂的焙烧温度、反应温度、反应时间、催化剂用量及醇油比对转化率的影响,确定了最优化的反应条件. 对产品脱钙精制工艺进行了研究, 考察了三种络合剂的脱钙性能. 结果表明,柠檬酸是一种很好的可用于生物柴油的脱钙剂,精制后生物柴油的主要指标符合国内外同类产品的标准.     

A new route of the reaction of EtAlCl2 with α-olefins catalyzed by Ti complexes

A new method for the synthesis of dialkyl(ethyl)alanes by the reaction of EtAlCl₂ with -olefins in the presence of Mg and a catalytic amount of Cp₂TiCl₂ (Ti(OPrⁱ)₄, Ti(OBuⁿ)₄) in THF was developed.     

液/液两相催化新进展--温控非水液/液两相催化

温控非水液/液两相催化,是指一类由两种或多种液态有机物组成的催化反应体系,其特点是体系的相态变化可通过温度来调控,即体系在高温时相互混溶呈均相,低温不溶分成两相,催化剂和产物分别处于两相,从而为解决均相催化剂分离难的问题开拓了一个新方向,是液/液两相催化研究领域最引人注目的进展之一.首次以"温控"为主线将氟两相催化作为温控液/液两相催化的一个特定类型纳入"温控非水液/液两相催化"范畴,并与其它通过温度来调控的有机液/液两相和作者提出的温控相分离催化串在一起作一较为详细的评述.     

Alkane oxygenation with H2O2 catalysed by FeCl3 and 2,2′-bipyridine

The H₂O₂-FeCl₃-bipy system in acetonitrile efficiently oxidises alkanes predominantly to alkyl hydroperoxides. Turnover numbers attain 400 after 1 h at 60 °C. It has been assumed that bipy facilitates proton abstraction from a H₂O₂ molecule coordinated to the iron ion (these reactions are stages in the catalytic cycle generating hydroxyl radicals from the hydrogen peroxide). Hydroxyl radicals then attack alkane molecules finally yielding the alkyl hydroperoxide.     

Synthesis and Structure of Mixed Distannoxane Dimers [ClR_2SnOSnR''''_2Cl]_2

1,1,3,3-Tetraorganodistannoxanes [XR2SnOSnR2X]2 (R = alkyl, Ph; X = halogen, NCS, OAc, OR) are a kind of organotin oxo clusters. They have received considerable attention because they are useful catalysts for many reactions1-5. And recently S. W. Ng reported that [XR2SnOSnR2X]2 (R = Bu, X = OOCCH2SC(O)N(CH2CH2)2O) had more active antitumor activity than cis-platin in vitro6. A characteristic feature of symmetric tetraorganodistannoxanes in the solid state is their dimeriz…