Effect of immobilization of titanocene catalyst in aralkyl imidazolium chloroaluminate media on performance of biphasic ethylene polymerization and polyethylene properties

Abstract

], were applied as media of the Cp 2 TiCl 2 catalyst for biphasic ethylene polymerization. The studied aralkyl ionic liquids ensure greater stability of the catalyst at higher temperatures and more regular morphology of the produced polyethylene than analogous 1-n-alkyl-3-methylimidazolium chloroaluminates. The alkylaluminium compound participates in the termination reaction of the polymer chain. The catalyst is stable and enables recycling of the ionic liquid phase in the consecutive polymerization reactions. The [Ph-C 2 mim][AlCl 4 ] ionic liquid and AlEt 2 Cl alkylaluminium compound turned out to be the most suitable for the biphasic process. The influence of the kind of ionic liquid, alkylaluminium compound (AlEt 2 Cl and AlEtCl 2 ), activator/catalyst molar ratio, reaction temperature, reaction time and catalyst recycling on the polymerization performance as well as polyethylene properties such as molecular weight (M w ), polydispersity, melting temperature, crystallinity degree, bulk density and particle size is presented.

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

“…These results are unusual for the polymerization preformed using the metallocene catalytic systems, in which the β-H elimination is dominant termination reaction [ 54 ]. This phenomenon can be explained by the influence of alkylaluminium activator on termination reaction, what was previously observed in our work [ 55 ]. The dominant unsaturated groups in the E-NB copolymerization catalyzed by the homogeneous C6 complex were trisubstituted vinylene like also vinylidene groups (T, VD1 and VD2).…”

High crystallinity polyethylene obtained in biphasic polymerization using pyridinium chloroaluminate ionic liquid

“…The PE yield increases with the increase of the molar ratio activator/catalyst, but only to an optimal value. This is connected with proper acidity of the ionic liquid phase, necessary for activity of the metallocene catalyst [6,23].…”

“…This effect can be explained by the physical properties of the studied ionic liquids, especially by their viscosity and density [22], that have an effect on the performance of the biphasic systems [5,6,27].…”

“…Apart of the strong signal about 1.30 ppm ascribed to methylene groups (-CH 2 -), the much weaker signals are seen, resulting from the presence of vinyl groups (4.87-4.97 ppm), allylic methylene groups (2.01-2.06 ppm), and methyl groups (0.85 ppm). The signal at 3.53 ppm indicates the presence of hydroxyl groups (-OH) in the polymer chain [6,29,30].…”

“…The waste of the expensive transition metal compound can be minimized and the polymerization yield can be improved. Moreover, kind of the applied ionic liquid has considerable influence on performance of the polymerization reaction [5,6].…”