Olefin poly/oligomerizations by metal precatalysts bearing non–heterocyclic N–donor ligands

Nickel Catalyzed Olefin Oligomerization and Dimerization

“…Thus, although nickel complexes have been partly summarized in the literature, 4,5,7,11,12,[57][58][59][60][61][62][63][64][65] this chapter aims to give an overview of the main advances made since 2010 in ligand design with a focus on selective ethylene oligomerization. It is necessary to mention that this task turns out to be arduous and complex and reflects the main challenges of the last decades in nickel-catalyzed olefin oligomerization.…”

Structural and Thermal Properties of Ethylene-Norbornene Copolymers Obtained Using Vanadium Homogeneous and SIL Catalysts

“…Copolymer microstructure and properties are tightly connected with conditions of reaction and type of catalyst. Nowadays, interest in vanadium complexes is currently growing because they enable to obtain polymers of high molecular weight ( M w ) and narrow molecular weight distribution ( M w /M n ), copolymers of ethylene with higher 1-olefins or cyclic olefins with high comonomer incorporation in the copolymer chain [ 1 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. However, a big disadvantage of vanadium compounds is their instability, they are easily reduced to lower, inactive oxidation state.…”

“…To prevent this, ethyl trichloroacetate (ETA) reactivator is often used. Another method of stabilizing the vanadium active center is applying ligands with electron-donating atoms, oxygen or nitrogen [ 14 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. In our previous works it was found that the vanadium metallocene and post-metallocene catalysts with oxazoline ligand activated by the traditional organoaluminium compound (AlEt 2 Cl) and ETA can be successfully used for COC synthesis [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

Titanium and Vanadium Catalysts with 2-Hydroxyphenyloxazoline and Oxazine Ligands for Ethylene-Norbornene (co)Polymerization

“…Similar to the synthesis of polyethylene and ethylene copolymers with 1-olefins, in particular E-NB copolymers, the catalysts with zirconium [1,6,12,19] and titanium [8,12,20] atoms in the active center are the most often studied. The vanadium catalysts [21,22] are less studied, but they receive interest because it is possible to obtain the E-NB copolymers with high molecular weight, narrow molecular weight distribution, and high norbornene incorporation [13,[15][16][17][18][23][24][25][26]. In contrast to the zirconium and titanium catalysts, which work best after methylaluminoxane (MAO) activation [1,[6][7][8]12,19,20], the vanadium catalysts reveal the best performance when activated by AlEt 2 Cl in the presence of reactivator, ethyl trichloroacetate (ETA), which prevents reduction of the vanadium atom to lower oxidation states and influences positively termination and re-initiation processes [13][14][15][16][17][18].…”

“…In contrast to the zirconium and titanium catalysts, which work best after methylaluminoxane (MAO) activation [1,[6][7][8]12,19,20], the vanadium catalysts reveal the best performance when activated by AlEt2Cl in the presence of reactivator, ethyl trichloroacetate (ETA), which prevents reduction of the vanadium atom to lower oxidation states and influences positively termination and re-initiation processes [13][14][15][16][17][18]. A method of stabilizing the vanadium active center, and in consequence, a prolongation of catalyst lifetime, is to apply ligands with electron-donating atoms-oxygen, nitrogen, or phosphorus [14][15][16][17][18][20][21][22][23][24][25][26][27][28]. Heterocyclic compounds like 4,5-dihydro-1,3-oxazole (oxazoline) derivatives seem to meet this requirement.…”