New Titanium(IV)-Alkoxide Complexes Bearing Bidentate OO Ligand with the Camphyl Linker as Catalysts for High-Temperature Ethylene Polymerization and Ethylene/1-Octene Copolymerization

Vladislav A Tuskaev; Svetlana Ch Gagieva; Dmitrii A Kurmaev; Yulia V Nelyubina; Petr V Primakov; Maria D Evseeva; Evgenii K Golubev; Mikhail I Buzin; Galina G Nikiforova; Pavel B Dzhevakov; Viktor I Privalov; Kasim F Magomedov; Boris M Bulychev

doi:10.3390/polym14214735

New Titanium(IV)-Alkoxide Complexes Bearing Bidentate OO Ligand with the Camphyl Linker as Catalysts for High-Temperature Ethylene Polymerization and Ethylene/1-Octene Copolymerization

Polymers (Basel). 2022 Nov 4;14(21):4735. doi: 10.3390/polym14214735.

Authors

Affiliations

¹ Department of Chemistry, M. V. Lomonosov Moscow State University, 1 Leninskie Gory, 119992 Moscow, Russia.
² A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow, Russia.
³ Department of Chemistry, Mendeleev University of Chemical Technology of Russia, Miusskaya pl. 9, 125047 Moscow, Russia.
⁴ Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Sciences, Profsoyuznaya Str. 70, 117393 Moscow, Russia.
⁵ Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119991 Moscow, Russia.

Abstract

In order to increase the thermal stability of olefin polymerization precatalysts, new titanium(IV) complexes with diolate ligands differing in the degree of steric hindrances were synthesized from readily available precursor (±)camphor. The structures of the complexes 1-2 were established by X-ray diffraction. Complexes 1-4 in the presence of an activator {Et_nAlCl_3-n + Bu₂Mg} catalyzed the synthesis of UHMWPE with an M_v up to 10 million and a productivity of up to 3300 kg/mol_Ti·atm·h. The obtained polymers are obviously characterized by a low density of macromolecular entanglement, which makes it possible to use the solid-phase method for their processing. The mechanical characteristics of the oriented UHMWPE films had a breaking strength up to 2.7 GPa and an elastic modulus of up to 151 GPa. The precatalysts 1-4 were also active in ethylene/1-octene copolymerization. The comonomer content was in the range of 1.4-4.6 mol%. The use of a rigid linker and an increase in the steric load of the diolate complexes ensured the thermal stability of the catalytic system in the range of 50-70 °C.

Keywords: OO-ligand; Ti(IV) complexes; polyolefin elastomers; thermal stability; ultra-high molecular weight polyethylene.

Grants and funding

18-13-00375/Russian Science Foundation