A new post-metallocene catalyst for alkene polymerization: copolymerization of ethylene and 1-hexene with titanium complexes bearingN,N-dialkylcarbamato ligands

Abstract

A new type of post-metallocene polymerization catalyst based on titanium complexes with N,N-dialkylcarbamato ligands was used to copolymerize ethylene and 1-hexene. These easy-to-synthesize and stable complexes in combination with different organoaluminium co-catalysts produce random ethylene/1-hexene copolymers characterized by a broad molecular weight distribution and high 1-hexene incorporation, as confirmed by SEC, DSC and 13 C NMR analysis. The influence of the main reaction parameters on the polymerization reactions was studied including the type of catalyst components, solvent, temperature, the ethylene partial pressure and the [Al]/[Ti] ratio in the catalyst. A higher activity and a higher 1-hexene incorporation were achieved with AlMe 3 -depleted methylalumoxane as co-catalyst and chlorobenzene as solvent. EXPERIMENTAL MaterialsAll manipulations of air-and water-sensitive compounds were performed under dry nitrogen using standard Schlenk and vacuum-line techniques. Ethylene (>99%; Rivoira, Torino, Italy) was used as received. Toluene (Baker, Deventer, Holland) and chlorobenzene (Fluka, Steinheim, Germany) were dried by refluxing for 8 h over a K/Na alloy and CaH 2 , respectively, and distilled under dry nitrogen before use. TiCl 4 (Fluka), MAO (toluene solution, 10 wt%), ethylaluminium sesquichloride (Et 3 Al 2 Cl 3 , 97%) and Al i Bu 3 (toluene solution, 25 wt%) were purchased from

Recent Advances in the Chemistry of Metal Carbamates

“…Subsequently, [TiCl 2 (O 2 CNMe 2 ) 2 ] [ 139 ], [Ti(O 2 CNR 2 ) 4 ] (R = Me, Et, Pyrr) [ 139 , 172 , 329 ], [Nb(O 2 CNR 2 ) 5 ] (R = Me, Et), [Nb(O 2 CNEt 2 ) 4 ] and [Nb(O 2 CNEt 2 ) 3 ] [ 280 ] were studied in ethylene and propylene (homo)polymerization and ethylene/1-hexene copolymerization. Notably, the catalytic activities of these carbamato complexes were higher compared to those of the respective metal halide precursors.…”

The Contribution of CIRCC Partners to the Birth and Growth of CO2 Chemistry

“…Such compounds were used as precursors of catalysts or catalysts themselves in reactions such as: olefin‐polymerization and co‐polymerization, [42a–d] synthesis of specialty chemicals; [43] ring opening polymerization [44] or in material science [45] . Even the biological properties of the carbamato‐complexes was investigated with Group 1B elements [46] …”

Titanium Complex Containing a Saligenin Ligand - New Universal Post-Metallocene Polymerization Catalyst: Copolymerization of Ethylene with Higher α-Olefins

“…They are usually synthesized using heterogeneous Ziegler-Natta and metallocene-based catalysts. At the present time, the point of attention in alkene polymerization chemistry has shifted to postmetallocene catalysts based on a variety of multidentate complexes of transition metals [3][4][5][6][7][8]. Similar to metallocene catalysis, post-metallocene catalysts also afford the control of the chain microstructure, copolymer homogeneity and morphology through the choice of the multidentate ligands and polymerization conditions.…”