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  • 1
    Electronic Resource
    Electronic Resource
    Polymerization of propene with the XTiCl3/MgCl2-Al(i-Bu)3 catalyst system (X = cyclopentadienyl, pentamethylcyclopentadienyl, indenyl, and heptamethylindenyl) in the absence and presence of a lewis base (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 291-297 
    Details
    ISSN: 0887-624X
    Keywords: combination of ziegler-natta and metallocene catalysts ; half metallocene catalysts supported on magnesium dichloride ; activation by ordinary alkylaluminums ; improvement of catalyst isospecificity by electron donors ; microstructure of isotactic polypropene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several kinds of MgCl2-supported half titanocene (XTiCl3; X = cyclopentadienyl, pentamethylcyclopentadienyl, indenyl, and heptamethylindenyl) catalysts were prepared and applied to propene polymerization using Al(i-Bu)3a as cocatalyst. It was confirmed from the catalyst analysis that the ligand (X) is attached to titanium even after the reaction with Al(i-Bu)3. When polymerization was conducted without any external donor, those catalysts predominantly gave atactic PP. However, addition of a suitable monofunctional Lewis base like ethylbenzoate caused to change the stereospecificity of polymer from aspecific into highly isospecific. On the other hand, the use of a bifunctional donor like di-n-butylphthalate killed the activity almost completely. The isotactic PP was found to have a microstructure similar to that obtained with metallocene catalysts. © 1997 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Ethene-propene copolymerization with the MgCl2-supported dichlorobis(4,4,4-trifluoro-1-phenyl- 1,3-butanedionato)titanium catalyst activated by an ordinary trialkylaluminum (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2735-2740 
    Details
    ISSN: 0887-624X
    Keywords: Ti(BFA)2Cl2/MgCl2 catalyst (BFA = 4,4,4-trifluoro-1-phenyl-1,3-butanedione) ; activation by trialkylaluminum with or without diisopropyldimethoxysilane ; copolymerization of ethene with propene ; homogeneity of active species ; homogeneity of copolymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Ti(BFA)2Cl2/MgCl2-Al(C2H5)3 catalyst (BFA = 4,4,4-trifluoro-1-phenyl-1,3-butanedione) modified by DIPDMS (diisopropyldimethoxysilane), which had been proved to yield an extremely high isotactic polypropene in high selectivity, was tested for the copolymerization of ethene with propene. The analysis of resulting copolymers by CFC (cross fractionation chromatography) indicated the formation of a small quantity of ethene-rich copolymers as a byproduct, suggesting that the catalyst possesses not only Ti(III) species but a small portion of Ti(II) species. Whereas, the same catalyst without being modified by an external donor selectively yielded propene-rich random copolymers resulting from Ti(III) species in high yields. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2735-2740, 1998
    Additional Material: 5 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Propene polymerization with the MgCl2-supported dichlorobis(β-diketonato)titanium catalysts activated by ordinary alkylaluminums (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 129-135 
    Details
    ISSN: 0887-624X
    Keywords: MgCl2-supported dichlorobis(β-diketonato)titanium catalysts ; catalyst activation by ordinary trialkylaluminums ; propene polymerization ; effect of Lewis bases on catalyst isospecificity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several kinds of dichlorobis(β-diketonato)titanium complexes, i.e., Ti(ace-tylacetonato)2Cl2, Ti(1-benzoylacetonato)2Cl2, Ti(2,2,6,6-tetramethyl-3,5-heptanedionato)2Cl2 and Ti(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)2Cl2, were synthesized and the corresponding MgCl2-supported catalysts were prepared by impregnation method. The test of them for propene polymerization revealed that those MgCl2-supported catalysts could be activated not only by methylaluminoxane (MAO) but also by ordinary alkylaluminums as well. The effect of typical Lewis bases on the catalyst performance was investigated in some detail, which indicated that organic silanes are most effective for the improvement of isospecificity of those catalysts. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 129-135, 1998
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of propene pressure on the isotacticity of polypropene produced with typical C1-symmetric metallocene and Ziegler-Natta catalysts (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 2899-2904 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of propene was conducted at 40°C under reduced pressure (0.35 - 1.0 atm) using the C1-Symmetric threo-iPr(3-tBuCp)(3-tBuInd)ZrCl2/MAO and TiCl4/MgCl2/Al(iBu)3 catalyst systems and the effect of propene pressure on the microstructure of the resulting isotactic polypropene was investigated. In the case of C1-symmetric metallocene, the [mmmm]-pentad fraction decreased moderately with decreasing propene pressure, but the magnitude of decrease was much smaller than those reported by Busico et al. using typical C2-symmetric metallocenes. Whereas, the [mmmm]-pentad fraction of isotactic polypropene obtained with the conventional Ziegler-Natta catalyst did not change so much in the pressure range. Thus, epimerization of the growing polymer chain was found to be drastically dependent upon the catalyst system.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980919
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis of MgCl2-supported dichlorobis(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)titanium catalysts with different titanium contents and their application to propene polymerization (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1495-1499 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Various MgCl2-supported Ti(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)2Cl2 catalysts with different Ti contents (0.017 ∼ 0.002 mmol/g) were synthesized and applied to propene polymerization using triethylaluminium and di-i-propyldimethoxysilane (DIPDMS) as the cocatalyst and external donor, respectively. When polymerization was conducted in the absence of DIPDMS, neither the activity nor the isospecificity of catalyst were dependent upon the Ti content. However, the effect of DIPDMS on the catalyst performance was found to be markedly dependent upon the Ti content, i.e., the addition of DIPDMS to the catalyst with low Ti content caused a prominent increase in the activity for isotactic polymerization. As a result, the present catalyst with low Ti content gave a highly isotactic polypropene with Tm = 169.3°C and [mmmm] 〉 99% in high selectivity (I.I. = 97.7%).
    Additional Material: 2 Ill.
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