Supported permethylindenyl titanium catalysts for the synthesis of disentangled ultra-high molecular weight polyethylene (disUHMWPE)

Abstract

New permethylindenyl-phenoxide (PHENI*) ansa-metallocene titanium complexes immobilised on inorganic solid supports are highly effective catalysts for ethylene polymerisation capable of producing disentangled ultra-high molecular weight polyethylene.

Efficient synthesis of thermoplastic elastomeric amorphous ultra-high molecular weight atactic polypropylene (UHMWaPP)

“…Initial polymerisation studies using sMAO-supported solid catalysts were performed in 150 mL ampoules using 10 mg 1 sMAO -4 sMAO with 2 bar propylene in 50 mL hexanes for 30 minutes with MAO ([Al MAO ]/[Ti] = 1000) acting as co-catalytic initiator and scavenger across a temperature of polymerisation (T p ) range of 60 ≤ T p ≤ 80 °C (Table 1). As was found previously for ethylene polymerisation using supported catalysts, 29 Table 1 Propylene polymerisation results with sMAO supported catalysts 1 sMAO -4 sMAO . Polymerisation conditions: 10 mg catalyst, 2 bar propylene, 50 mL hexanes, 30 minutes, and MAO ([…”

“…48 We have previously introduced the PHENI* ligand which is a development of PHENICS ligands, incorporating the many benefits of I*, and which shows higher activities both than the I* CGC analogues introduced by Williams et al and the indenyl PHENICS analogue. 25,29,43…”

“…25,29,43 Titanium dichloride complexes 1-3, utilising PHENI* ligands, Me2 SB( R1R2 ArO,I*)TiCl 2 ({(η 5 -C 9 Me 6 )Me 2 Si(2-R 1 -4-R 2 -C 6 H 2 O)}TiCl 2 ; R 1 , R 2 = Me, t Bu, or CMe 2 Ph), were synthesised as previously reported. 29 These complexes, and additionally the indenyl-PHENICS complex 4 ( Me2 SB( tBu,Me ArO,I)TiCl 2 ; {(η 5 -C 9 H 6 )Me 2 Si(2-t Bu-4-Me-C 6 H 2 O)}TiCl 2 ; I = C 9 H 6 ), were then immobilised on sMAO following a standard procedure, 49 with [Al sMAO ]/[Ti] = 200, to afford 1 sMAO -4 sMAO (Chart 1).…”

“…48 We have previously introduced the PHENI* ligand which is a development of PHENICS ligands, incorporating the many benefits of I*, and which shows higher activities both than the I* CGC analogues introduced by Williams et al and the indenyl PHENICS analogue. 25,29,43 Titanium dichloride complexes 1-3, utilising PHENI* ligands, Me2 SB( R1R2 ArO,I*)TiCl 2 ({(η 5 -C 9 Me 6 )Me 2 Si(2-R 1 -4-R 2 -C 6 H 2 O)}TiCl 2 ; R 1 , R 2 = Me, t Bu, or CMe 2 Ph), were synthesised as previously reported. 29 These complexes, and additionally the indenyl-PHENICS complex 4 ( Me2 SB( tBu,Me ArO,I)TiCl 2 ; {(η 5 -C 9 H 6 )Me 2 Si(2-t Bu-4-Me-C 6 H 2 O)}TiCl 2 ; I = C 9 H 6 ), were then immobilised on sMAO following a standard procedure, 49 with [Al sMAO ]/[Ti] = 200, to afford 1 sMAO -4 sMAO (Chart 1).…”

“…21,22 One such class of elastomer, ethylene propylene rubber (EPM), is commercially synthesised using highly active titanium cyclopentadienyl-amidinate complexes. 23 Post-metallocene ansa-bridged complexes based on nitrogen and oxygen donorssuch as the Constrained Geometry Complexes (CGCs), 24,25 Phenoxy-Induced Complexes of Sumitomo (PHENICS), [26][27][28] and our recently-reported permethylindenyl (C 9 Me 6 , Ind*, I*) analogue, PHENI* 29 have been shown to be highly active catalysts for ethylene polymerisation, with the latter producing substantially disentangled UHMWPE and demonstrating a remarkable 22-fold increase in activity over the analogous PHENICS complex. In the polyethylene case, solid polymethylaluminoxane (sMAO) has proven to be a highly competent dual-function activating catalyst support, forming strongly immobilised metallocene catalysts for use in heterogeneous slurry-phase reactions.…”