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Active Catalytic System (active + catalytic_system)
Selected AbstractsCuI/DABCO as a Highly Active Catalytic System for the Heck-Type Reaction.CHEMINFORM, Issue 44 2005Jin-Heng Li Abstract For Abstract see ChemInform Abstract in Full Text. [source] Polymerisation of ethylene catalysed by mono-imine-2,6-diacetylpyridine iron/methylaluminoxane (MAO) catalyst system: effect of the ligand on polymer microstructurePOLYMER INTERNATIONAL, Issue 12 2002Susete Fernandes Abstract The complex, {1-{6-[(2,6-diisopropylphenyl)-ethaneimidoyl]-2-pyridinyl}-1-ethanone}iron(II) dichloride (2), has been synthesised and characterised. Treatment of complex 2 with methylaluminoxane resulted in a very active catalytic system for the preparation of polyethylene (PE). The system shows activities in the order of magnitude 107,g (PE) mol,1(Fe) h,1 bar,1. Characterisation by 13C NMR indicated that branched PE was obtained and that experimental conditions affect polymer microstructure. PE produced contained six to eight branches per 100 carbons. © 2002 Society of Chemical Industry [source] Highly Active and Removable Ruthenium Catalysts for Transition-Metal-Catalyzed Living Radical Polymerization: Design of Ligands and CocatalystsCHEMISTRY - AN ASIAN JOURNAL, Issue 8-9 2008Makoto Ouchi Dr. Abstract The systematic search and design of phosphine ligands (PR3) and amine cocatalysts resulted in obtaining pentamethyl-cyclopentadienyl (Cp*) ruthenium(II) phosphine complexes [RuCp*Cl(PR3)2], which are highly active and removable catalysts, for transition-metal-catalyzed living radical polymerization of methyl methacrylate (MMA). The catalysts are conveniently prepared in situ from a tetrameric precursor [RuCp*(,3 -Cl)]4 and a selected phosphine (PR3). The combination of the meta -tolyl phosphine [P(m -Tol)3] ligand and a primary diamine cocatalyst [NH2(CH2)6NH2] provides a highly active catalytic system with precision control of the molecular weight of the polymer. The high activity enables a low catalyst dose and a high turn-over frequency without deteriorating the controllability. A hydrophilic amine cocatalyst (amino alcohol) in place of the diamine, further forms an active and removable catalyst; simple treatment with acidic water gave colorless polymers visually free from metal residues (>97,% removal; <64,ppm). [source] New [Ru3(CO)12]-Based Catalysts with Imidazolinium Salt, Diimine, or Bis(oxazoline) Ligands and Ruthenium Bis(oxazoline) Complex for Tandem Isomerisation/Claisen Rearrangement of Dienyl Ethers , X-ray Structure of [RuCl{(R,R)-bis(isopropyloxazoline)}(p -cymene)]BF4EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2003Hamed Ben Ammar Abstract The reaction of various 1,7-dienes in the presence of the three-component catalyst A: [Ru3(CO)12]/imidazolinium salt/Cs2CO3 (1:1:2) leads to the tandem alkene isomerisation/Claisen rearrangement affording ,,,-unsaturated aldehydes. Other three component catalysts: [Ru3(CO)12]/diimine/Cs2CO3 and [Ru3(CO)12]/benzoxazoline or chiral bis(oxazoline)/Cs2CO3 offer new active catalytic systems for these tandem reactions. Two ruthenium complexes containing optically active bis(oxazoline), [RuCl{(R,R)-bis(oxazoline)}(p -cymene)]BF4, were prepared and the X-ray structure of one of them (18) was established. The combination of chiral 18/imidazolinium salt/Cs2CO3 (1:1:2) catalysed the above reaction of 1,6-dienes and the results suggest initial catalytic isomerisation followed by a thermal Claisen rearrangement. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] | ||||||||||