TITLE

Metallocene-catalyzed olefin polymerizations using triphenylcyclopropenium tetrakis(pentafluorophenyl)borate as the activator

AUTHOR(S)
Li, Huiying; Neckers, Douglas C
PUB. DATE
June 2003
SOURCE
Canadian Journal of Chemistry;Jun2003, Vol. 81 Issue 6, p758
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Triphenylcyclopropenium (TPCP) tetrakis(pentafluorophenyl)borate activates bis(cyclopentadienyl)dimethyl titanium resulting in a highly reactive initiating system for the polymerization of styrene. In contrast to triphenylmethyl tetrakis(pentafluorophenyl)borate which is quite active in the absence of the metallocene, TPCP borate shows no activity for styrene polymerization in the absence of bis(cyclopentadienyl)dimethyl titanium. TPCP is the most efficient activator in the carbonium ion – borate class. We propose, based on 1H NMR evidence that reaction of Cp2TiMe2 and TPCP borate leads to the formation of the cationic Ti complex [Cp2TiMe]+B(C6F5)4–. Evidence for the latter is also provided by UV–vis spectroscopy in that we found a bathochromic shift of the Cp2TiMe2 LMCT absorption band from 361 to 482 nm in CH2Cl2 and 487 nm in toluene, respectively. Thermal decomposition of the cationic complex [Cp2TiMe]+B(C6F5)4– leads to less activity. The systems are good catalysts for ethylene polymerization as well, but are less active when using propylene. A conventional Ziegler–Natta coordination polymerization mechanism accounts for ethylene and propylene polymerization while a carbocationic polymerization mechanism is proposed for styrene.
ACCESSION #
10559397

 

Related Articles

  • Copolymerization of Carbon-carbon Double-bond Monomer (Styrene) with Cyclic Monomer (Tetrahydrofuran). Sari, F.; Ferrahi, M. I.; Belbachir, M. // Bulletin of Chemical Reaction Engineering & Catalysis;Dec2012, Vol. 7 Issue 2, p165 

    We reported in this work that the cationic copolymerization in one step takes place between carbon-carbon double-bond monomer styrene with cyclic monomer tetrahydrofuran. The comonomers studied belong to different families: vinylic and cyclic ether. The reaction is initiated with maghnite-H+ an...

  • CH+5: The never-ending story or the final word? Schreiner, Peter R.; Kim, Seung-Joon; Schaefer, Henry F.; von Ragué Schleyer, Paul // Journal of Chemical Physics;9/1/1993, Vol. 99 Issue 5, p3716 

    The closely related Cs(1), Cs(2), and C2v(3) structures of CH5+ have been reinvestigated with high level ab initio theory through the coupled cluster with single and double substitutions (CCSD), and CCSD with perturbatively included connected triple excitations [CCSD(T)] levels, employing a...

  • Structural relation between Si and SiC formed by carbon ion implantation. Eichhorn, F.; Schell, N.; Mu¨cklich, A.; Metzger, H.; Matz, W.; Ko¨gler, R. // Journal of Applied Physics;2/1/2002, Vol. 91 Issue 3, p1287 

    The formation of crystalline SiC by implantation of C ions into silicon is not a single-step process. The implantation results in an elastic distortion of the Si matrix lattice and in the formation of crystalline SiC particles, depending on ion fluence and thermal conditions during implantation...

  • Metallocene catalyst introduction available.  // Plastics News;3/5/2001, Vol. 13 Issue 1, p34 

    Announces the release of Rapra Technology Ltd.'s report 'Metallocene-Catalysed Polymerisation,' which provides a technical introduction to the subject of metallocene catalysts. Order information.

  • Copolymerization of ethylene and 4-vinylcyclohexene by various metallocenes in the presence of Al(iBu)[SUB3]/[Ph[SUB3]C][B(C[SUB6]F[SUB5])[SUB4]]. Il Kim; Young-tae Kim // e-Polymers;Oct2001, p1 

    Cites findings of a study in which copolymerization of ethylene and 4-vinylcyclohexene (VCH) were carried out by various metallocenes in the presence of Al(iBu)[SUB3]/[Ph[SUB3]C][B(C[SUB6]F[SUB5])[SUB4]]. Process used to insert VCH into the copolymer; Results of calculation of copolymerization...

  • Bis(η[sup5]-cyclopentadienyl)bistriphenylsilanolato-zirconium(IV): a new precursor for ethylene polymerization catalysis. Altomare, Angelina; Candian, Roberta; Michelotti, Marco; Pampaloni, Guido; Ciardelli, Francesco // e-Polymers;Jul2001, p1 

    Reports that trialkylsilanols modify and also improve the catalytic performance in ethylene polymerization when added to zirconocene/methyl-aluminoxane (MAO) systems. Role of MAO with respect to the metallocene complex; Homopolymerization of ethylene in the presence of MAO; Characterization of...

  • Infrared spectroscopy of the molecular hydrogen solvated carbonium ions, CH+5(H2)n (n=1–6). Boo, Doo Wan; Lee, Yuan T. // Journal of Chemical Physics;7/8/1995, Vol. 103 Issue 2, p520 

    The infrared spectra for the molecular hydrogen-solvated carbonium ions, CH+5(H2)n (n=1–6) in the frequency range of 2700–4200 cm-1 are presented. Spectroscopic evidence was found in support of the scrambling of CH+5 through the large amplitude motions such as the CH3 internal...

  • Structure -- activity relations in metallocene catalysts -- (Part I). Kulshreshtha, A. K. // Chemical Business;Apr2005, Vol. 19 Issue 4, p44 

    Discusses the structure-activity in metallocene catalysts. Background on metallocenes; Role of metallocenes in ethylene polymerization; Overview of the polymer properties of metallocenes.

  • The Design of Group 4 Cyclopentadienyl, Olefin-Polymerisation Catalysts.  // South African Journal of Chemistry;2001, Vol. 54, p1 

    This review focuses on Group 4 metallocenes and their use in the polymerisation of ?-olefins. A brief overview of their history as well as theories concerning the mechanistic details of the polymerisation reaction precedes a discussion on the design of these polymerisation catalysts. This...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics