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

• DOI: 10.1007/s00289-012-0809-8
• Publication Date: 2012-07-15T19:57:26Z
• Authors: Wioletta Ochędzan...; Katarzyna Dziubek; Krystyna Czaja
• Keywords: polyethylene; Chemistry(all); Polymers and Plastics; Materials Chemistry; metallocene catalyst; Condensed Matter Physics; 01 natural sciences; ionic liquid; 0104 chemical sciences

1-(2-Phenylethyl)-3-methylimidazolium and 1-benzyl-3-methylimidazolium chloroaluminates, [Ph-C2mim][AlCl4] and [Bzlmim][AlCl4], were applied as media of the Cp2TiCl2 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-C2mim][AlCl4] ionic liquid and AlEt2Cl alkylaluminium compound turned out to be the most suitable for the biphasic process. The influence of the kind of ionic liquid, alkylaluminium compound (AlEt2Cl and AlEtCl2), 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.