MRC  Vol.1 No.3 , October 2012
Titanasilsesquioxane-Alkylaluminum Catalyst System for Ethylene Polymerization
Abstract: Homogeneous Ti(IV) complexes covalently anchored to Polyhedral Oligomeric Silsesquioxane (POSS) have been synthesized by the stoichiometric reaction between titanium(IV)alkoxide and (iso-Octyl)7Si7O9(OH)3. These catalyst precursors formulated as [Ti(OR)(iso-Octyl)7Si7O12] were characterized by physicochemical and spectroscopic methods. These supported catalysts are found to be active in polymerization of ethylene at high temperatures in presence of ethylaluminum sesquichloride (Et3Al2Cl3, EASC) as co-catalyst. The polyethylene obtained are generally linear, crystalline and display low molecular weight distribution. The microstructure of the polymer was analyzed by NMR and FT-IR spectroscopic methods which indicated a chain transfer reaction to aluminum. The unique molecular properties of PE formed has been compared with commercial micronized PE wax which find industrial applications in surface coating and ink formulations. The effect of reaction conditions on catalytic behaviour is described.
Cite this paper: A. Mehta, G. Tembe, P. Parikh and G. Mehta, "Titanasilsesquioxane-Alkylaluminum Catalyst System for Ethylene Polymerization," Modern Research in Catalysis, Vol. 1 No. 3, 2012, pp. 29-42. doi: 10.4236/mrc.2012.13005.

[1]   D. S. McGuinness, “Olefin Oligomerization via Metallacycles: Dimerization, Trimerization, Tetramerization, and Beyond,” Chemical Reviews, Vol. 111, No. 3, 2011, pp. 2321-2341. doi:10.1021/cr100217q

[2]   D. F. Wass, “Chromium-Catalyzed Ethene Trimerization and Tetramerization-Breaking the Rules in Olefin Oligomerization,” Dalton Transactions, No. 8, 2007, pp. 816-819. doi:10.1039/b616291f

[3]   G. J. P. Britovsek, V. C. Gibson and D. F. Wass, “The Search for New-Generation Olefin Polymerization Catalysts: Life beyond Metallocenes,” Angewandte Chemie, International Edition, Vol. 38, No. 4, 1999, pp. 428-447. doi:10.1002/(SICI)1521-3773(19990215)38:4<428::AID-ANIE428>3.0.CO;2-3

[4]   J. T. Dixon, M. J. Green, F. M. Hess and D. H. Morgan, “Advances in Selective Ethylene Trimerization—A Critical Overview,” Journal of Organometallic Chemistry, Vol. 689, No. 23, 2004, pp. 3641-3668. doi:10.1016/j.jorganchem.2004.06.008

[5]   F. J. Karol, K. J. Cann and B. E. Wagner, “Transition metals and Organometallics as Catalysts for Olefin Polymerization,” In: W. Kaminsky and H. Sinn, Eds., Springer-Verlag: New York, 1988, 442 p.

[6]   G. G. Hlatky, “Heterogeneous Single Site Catalysts for Olefin Polymerization,” Chemical Reviews, Vol. 100, No. 4, 2000, pp. 1347-1376. doi:10.1021/cr9902401

[7]   E. I. Iiskola, S. Timonen, T. T. Pakkanen, O. H?rkki, P. Lehmus and J. V. Sepp?l?, “Cyclopentadienyl Surface as a Support for Zirconium Polyethylene Catalysts,” Macromolecules, Vol. 30, No. 10, 1997, pp. 2853-2859. doi:10.1021/ma960739m

[8]   T. Arai, H. T. Ban, T. Uozumi and K. Soga, “Synthesis of Poly(Siloxane)-Supported Zirconocene Catalysts and Application to Olefin Polymerizations,” Journal of Polymer Science a Polymer Chemistry, Vol. 36, No. 3, 1998, pp. 421-428. doi:10.1002/(SICI)1099-0518(199802)36:3<421::AID-POLA6>3.0.CO;2-U

[9]   D. G. H. Ballard, “Pi and Sigma Transition Metal Carbon Compounds as Catalysts for the Polymerization of Vinyl Monomers and Olefins,” Advances in Catalysis, Vol. 23, 1973, pp. 263-325. doi:10.1016/S0360-0564(08)60303-X

[10]   J. Schwartz and M. D. Ward, “Silica Supported Zirconium Hydrides as Isomerization or Hydrogenation Catalysts for Long Chain Olefins,” Journal of Molecular Catalysis, Vol. 8, No. 4, 1980, pp. 465-469. doi:10.1016/0304-5102(80)80085-X

[11]   S. A. King and J. Schwartz, “Chemistry of (Silica) Zirconium Dihydride,” Inorganic Chemistry, Vol. 30, No. 19, 1991, pp. 3771-3774. doi:10.1021/ic00019a040

[12]   S. M. Pillai, G. L. Tembe, M. Ravindranathan and S. Sivaram, “Dimerization of Ethylene to 1-Butene Catalyzed by the Titanium Alkoxide-Trialkylaluminum System,” Industrial & Engineering Chemistry Research, Vol. 27, No. 11, 1988, pp. 1971-1977. doi:10.1021/ie00083a003

[13]   P. D. Smith, D. D. Klendworth and M. P. McDaniel, “Ethylene Dimerization over Supported Titanium Alkoxides,” Journal of Catalysis, Vol. 105, No. 1, 1987, pp. 187-198. doi:10.1016/0021-9517(87)90018-2

[14]   G. L. Tembe and M. Ravindranathan, “Oligomerization of Ethylene to Linear a-Olefins by a Titanium Aryl Oxide-Alkylaluminum Catalyst,” Industrial & Engineering Chemistry Research, Vol. 30, No. 10, 1991, pp. 2247-2252. doi:10.1021/ie00058a002

[15]   T. Gueta-Neyroud, B. Tumanskii, M. Kapon and M. S. Eisen, “Synthesis and Characterization of Dichlorotitanium Alkoxide Complex and Its Activity in the Polymerization of α-Olefins,” Macromolecules, Vol. 40, No. 15, 2007, pp. 5261-5270. doi:10.1021/ma070771o

[16]   R. W. J. M. Hanssen, A. Meetsma, R. A. van Santen and H. C. L. Abbenhuis, “Synthesis, Structure Characterization, and Transmetalation Reactions of a Tetranuclear Magnesium Silsesquioxane,” Inorganic Chemistry, Vol. 40, No. 16, 2001, pp. 4049-4052. doi:10.1021/ic0004131

[17]   R. Duchateau, “Incompletely Condensed Silsesquioxanes: Versatile Tools in Developing Silica-Supported Olefin Polymerization Catalysts”, Chemical Reviews, Vol. 102, No. 10, 2002, pp. 3525-3542. doi:10.1021/cr010386b

[18]   F. J. Feher, T. A. Budzichowski, K. Rahimian and J. W. Ziller, “Reaction of Incompletely Condensed Silsesquioxanes with Pentamethylantimony: A New synthesis of Metallasilsesquioxanes with Important Implications for the Chemistry of Silica Surfaces,” Journal of American Chemical Society, Vol. 114, No. 10, 1992, 3859-3866. doi:10.1021/ja00036a038

[19]   F. J. Brown and L. H. Vogt, “The Polycondensation of Cyclohexylsilanetriol,” Journal of American Chemical Society, Vol. 87, No. 19, 1965, pp. 4313-4317. doi:10.1021/ja00947a016

[20]   M. Crocker, R. H. M. Herold, A. G. Orpen and M. T. A. Overgaag, “Synthesis and Characterisation of Titanium Silasesquioxane Complexes: Soluble Models for the Active Site in Titanium Silicate Epoxidation Catalysts,” Journal of Chemical Society, Dalton Transaction, No. 21, 1999, pp. 3791-3804. doi:10.1039/a905887g

[21]   P. P. Pescarmona, J. C. van der Waal, I. E. Maxwell and T. Maschmeyer, “A New, Efficient Route to Titanium-Silsesquioxane Epoxidation Catalysts Developed by Using High-Speed Experimentation Techniques,” Angewandte Chemie International Edition in English, Vol. 40, No. 4, 2001, pp. 40-43.

[22]   R. Duchateau, R. A. van Santen and G. P. A. Yap, “Silica-Grafted Borato Cocatalysts for Olefin Polymerization Modeled by Silsesquioxane Borato Complexes,” Organometallics, Vol. 19, No. 5, 2000, pp. 809-816.

[23]   R. Duchateau, U. Cremer, R. J. Harmsen, S. I. Mohamud, H. C. L. Abbenhuis, R. A. van Santen, A. Meetsma, S. K. H. Thiele, M. F. H. van Tol and M. Kranenbürg, “Half-Sandwich Group 4 Metal Siloxy and Silsesquioxane Complexes: Soluble Model Systems for Silica Grafted Olefin Polymerization Catalysts,” Organometallics, Vol. 18, No. 26, 1999, pp. 5447-5459. doi:10.1021/om9904495

[24]   P. P. Pescarmona, J. J. T. Rops, J. C. van der Waal, J. C. Jansen and T. Maschmeyer, “High Speed Experimentational Techniques Applied to the Study of the Synthesis of Zeolites and Silsesquioxane,” Journal of Molecular Catalysis Part A Chemical, Vol. 182-183, 2002, pp. 319-325. doi:10.1016/S1381-1169(01)00494-0

[25]   F. Carniato, E. Boccaleri and L. Marchese, “A Versatile Route to Bifunctionalized Silsesquioxane (POSS): Synt- hesis and Characterisation of Ti-containing Aminopropy- lisobutyl-POSS,” Dalton Transactions, No. 1, 2008, pp. 36-39. doi:10.1039/b715664m

[26]   F. J. Feher, D. A. Newman and J. F. Walzer, “Silsesquioxanes as Models for Silica Surfaces,” Journal of American Chemical Society, Vol. 111, No. 5, 1989, pp. 1741- 1748. doi:10.1021/ja00187a028

[27]   F. J. Feher, T. A. Budzichowski, R. L. Blanski, K. J. Weller and J. W. Ziller, “Facile Syntheses of New Incompletely Condensed Polyhedral Oligosilsesquioxanes: [(c-(C5H9)7Si7O9(OH)3], [(c-(C7H13)7Si7O9(OH)3], and [(c-(C7H13)7Si6O7(OH)4],” Organometallics, Vol. 10, No. 7, 1991, pp. 2526-2528.

[28]   M. Crocker, R. H. M. Herold and A. G. Orpen, “Synthesis and Structural Characterisation of Tripodal Titanium Silsesquioxane Complexes: A New Class of Highly Active Catalysts for Liquid Phase Alkene Epoxidation,” Chemical Communications, No. 24, 1997, pp. 2411- 2412. doi:10.1039/a704969b

[29]   F. T. Edelmann, S. Gieβmann and A. Fischer, “Silsesquioxane Chemistry 4 Silsesquioxane Complexes of Titanium (III) and Titanium (IV),” Journal of Organometallic Chemistry, Vol. 620, No. 1-2, 2001, pp. 80-89. doi:10.1016/S0022-328X(00)00867-6

[30]   E. Keren and G. Sundararajan, “Polymerization of 1-Olefins by Zirconium/Titanium Precatalysts with O, N, O-Ligating Atoms-Can Aggregation of Catalyst be Inferred from the Reaction Profile?” Jornal of Polymer Science Part A Polymer Chemistry, Vol. 45, No. 16, 2007, pp. 3599-3610. doi:10.1002/pola.22109

[31]   M. Bia?ek, “Effect of Catalyst Composition on Chain- End-Group of Polyethylene Produced by Salen-Type Complexes of Titanium, Zirconium, and Vanadium,” Journal of Polymer Science Part A Polymer Chemistry, Vol. 48, No. 14, 2010, pp. 3209-3214. doi:10.1002/pola.24096

[32]   A. Kaji, Y. Akimoto and A. Murano, “NMR Study of Microstructure of Ultra High-Molecular Weight Poly- ethylene,” Journal of Polymer Science Part A Polymer Chemistry, Vol. 29, No. 13, 1991, pp. 1987-1991. doi:10.1002/pola.1991.080291320

[33]   Y. Li, L. Wang, H. Gao, F. Zhu and Q. Wu, “Novel Nickel (II) Complexes Chelating β-Diketiminate Ligands: Synthesis and Simultaneous Polymerization and Oligomerization,” Applied Organometallic Chemistry, Vol. 20, No. 7, 2006, pp. 436-442. doi:10.1002/aoc.1097

[34]   E. Aitola, K. Hakala, H. B. Fagerholm, M. Leskela and T. Repo, “High Molar Mass Ethene/1-Olefin Copolymers Synthesized with Acenaphthyl Substituted Metallocene Catalysts,” Journal of Polymer Science Part A Polymer Chemistry, Vol. 46, No. 1, 2008, pp. 373-382. doi:10.1002/pola.22387

[35]   G. J. P. Britovsek, M. Bruce, V. C. Gibson, B. S. Kimber- ley, P. J. Meddox, S. Mastroianni, S. J. McTavish, C. Redshaw, G. A. Solan, S. Stromberg, A. J. P. White and D. J. Williams, “Iron and Cobalt Ethylene Polymerization Catalysts Bearing 2, 6-Bis(Imino) Pyridyl Ligands: Synthesis, Structures, and Polymerization Studies,” Journal of American Chemical Society, Vol. 121, No. 38, 1999, pp. 8728-8740. doi:10.1021/ja990449w

[36]   H. Hirai, K. Hiraki, I. Noguchi and S. Makishima, “Electron Spin Resonance Study on Homogeneous Catalysts Derived from n-Butyl Titanate and Triethylaluminum,” Journal of Polymer Science Part A, Vol. 8, No. 1, 1970, pp. 147-156. doi:10.1002/pol.1970.150080113

[37]   P. H. Moyer, “Studies of the Reduction of Titanates and Alkoxytitanium (IV) Chlorides by Alkylaluminum Chlorides,” Journal of Polymer Science A, Vol. 3, No. 1, 1965, pp. 199-207. doi:10.1002/pol.1965.100030122

[38]   E. Angelescu, C. Nicolau and Z. Simon, “Electron Spin Resonance Investigations of Some Soluble Organometallic,” Journal of American Chemical Society, Vol. 88, No. 17, 1966, pp. 3910-3912. doi:10.1021/ja00969a004

[39]   R. A. Rothenbury, “Anomalous Effects of Catalyst Mole Ratio on Molecular Weight of Ziegler Polyethylene,” Journal of Polymer Science Part A, Vol. 3, No. 8, 1965, pp. 3038-3039.

[40]   T. Mole and E. A. Jeffery. “Organoaluminium Com- pounds,” Elsevier, New York, 1972.

[41]   R. D. J. Froese, D. G. Musaev, T. Matsubara and K. Morokuma, “Theoretical Studies of Ethylene Poly- merization Reactions Catalyzed by Zirconium and Titanium Chelating Alkoxide Complexes,” Journal of American Chemical Society, Vol. 119, No. 31, 1997, pp. 7190-7196. doi:10.1021/ja970861g

[42]   R. D. J. Froese, D. G. Musaev, T. Matsubara and K. Morokuma, “Theoretical Studies of the Factors Controlling Insertion Barriers for Olefin Polymerization by the Titanium-Chelating Bridged Catalysts. A Search for More Active New Catalysts,” Organometallics, Vol. 18, No. 3, 1999, pp. 373-379. doi:10.1021/om9809466

[43]   Y. Kim, Y. Han, M. Y. Lee, S. W. Yoon, K. H. Choi, B. G. Song and Y. Do, “New Half-Metallocene Catalysts Generating Polyethylene with Bimodal Molecular Weight Distribution and Syndiotactic Polystyrene,” Macromolecular Rapid Communication, Vol. 22, No. 8, 2001, pp. 573-578. doi:10.1002/1521-3927(20010501)22:8<573::AID-MARC573>3.0.CO;2-S