Novel Effective Catalyst Systems Based on Titanium(IV) Alkoxide Complexes for Copolymerization of Ethylene and Hexene-1

Olefin polymerization behavior of titanium(IV) alkoxo complexes with fluorinated diolate ligands: The impact of the chelate ring size and the nature of organoaluminum compounds

“…Ligand 2a was synthesized as described previously. [14] The synthesis of complex 3a was described previously, [9,15] and its 1 H and 13 C NMR spectra were found to match the published data. The released hydrogen fluoride was trapped in a flask with a solution of sodium hydroxide.…”

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

“…Compared to previously obtained titanium complexes with flexible aliphatic diolate ligands [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], complexes 1–4 with a rigid camphane framework were characterized by increased thermal stability. Complex 2 with an increased steric load at hydroxyl groups was able to produce UHMWPE even at a temperature of 70 °C.…”

“…Previously, we reported on the ability of various titanium(IV)–diolate complexes VII-X [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], including those with additional heteroatoms [ 23 , 24 , 25 , 26 , 27 ] ( Chart 1 ), to catalyze the (co)polymerization of ethylene in the presence of such Al/Mg activators. This group of postmetallocene precatalysts is poorly studied, which is most likely due to the specifics of their activation: in the presence of trialkylaluminum derivatives, alkylaluminum chlorides, or alkylalumoxanes (traditional activators in Ziegler–Natta catalysis), and the activity of these systems is low or does not manifest itself at all.…”

“…It is important to note that, in most cases, these catalytic systems produce disentangled UHMWPE, which can be processed by the solid-phase method into high strength-oriented films and tapes, which are in high demand in various industries. In addition, such catalytic systems effectively catalyze the copolymerization of ethylene with higher olefins, and in some cases, even higher productivity is achieved ofup to 5 tons of copolymer /mol atm·h [ 20 ].…”

“…An essential point limiting the possibility of the industrial implementation of this group of catalysts is their low thermal stability. As a rule, the maximum productivity of such systems is achieved at a temperature of 30 °C [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]; an increase in the polymerization temperature to 50–80 °C is accompanied by deactivation and a significant reduction in the polymer’s molecular weight. The aim of this work is the structural modification of the ligand environment of the metal, aimed at increasing the thermal stability of the considered precatalysts.…”