218604-62-7

Upstream product

• 22385-77-9 1-bromo-3,5-di-tert-butylbenzene 
• 10485-09-3 2-bromoindene 
• 594-19-4 tert.-butyl lithium 
• 197223-39-5 3,5-di-tert-butylphenyl boronic acid 
• 1460-02-2 1,3,5-Tri-tert-butylbenzene 
• 612-12-4 o-Xylylene dichloride 
• 64277-87-8 methyl 3,5-di(tert-butyl)benzoate 
• 16225-26-6 3,5-di-tert-butylbenzoic acid 

Relevant academic research and scientific papers

High comonomer selectivity in ethylene/hexene copolymerization by unbridged indenyl metallocenes

Catalysts derived from unbridged 2-arylindene metallocenes of Hf and Zr are active for ethylene/hexene copolymerization and show a much higher selectivity toward hexene than unsubstituted bis(indenyl) metallocenes. The ligand substitution pattern and the

Control of sequence distribution of ethylene copolymers: Influence of comonomer sequence on the melting behavior of ethylene copolymers

New unbridged mixed-ligand zirconocenes were synthesized, characterized, and studied in the copolymerizations of ethylene-propylene (EP) and ethylene - 1-hexene (EH). The MAO-activated metallocene [1-benzyl-2-(3′,5′-di-tert-butyl)phenylindenyl][2-phenylin

Propylene polymerization with sterically hindered unbridged 2-arylindene metallocenes

Metallocene catalyst systems derived from bis(2-phenylindenyl)zirconium dichloride (1) yield elastomeric polypropylenes of low to intermediate tacticity. The sterically hindered metallocene bis(2-(3,5-di-tert-butylphenyl)indenyl)zirconium dichloride (2) produces polypropylenes of much higher isotacticity than 1 ([mmmm] = 78% vs 44% in liquid propylene). Kinetic profiles of polymerizations conducted with 1/MMAO and 2/MMAO reveal that the initial rates of polymerization increase with increasing temperature; the activity of both catalysts decreases with time, but the decrease is less pronounced for 2/MMAO than for 1/MMAO. The polymer microstructure is highly dependent upon polymerization conditions: isotacticity decreases with increasing temperature and decreasing monomer concentration. Lower tacticity polypropylenes ([mmmm] = 40%) generated with 2/MMAO at low monomer concentrations contain a high percentage of [mmrm] stereoerrors, which is indicative of a stereoblock microstructure comprised of isotactic stereosequences of opposite relative configuration. Activation of bis(2-(3,5-di-tert-butylphenyl)indenyl)zirconium dimethyl (3) with [Ph3C] [B(C6F5)4] (4) or B(C6F5)3 (5) yielded catalysts with quite different polymerization behavior. A modest drop in productivity and isotacticity in propylene polymerization is observed when 3 is activated with 4, relative to MMAO, but catalysts derived from 3/B(C6F5)3 exhibited low productivity and afforded amorphous polypropylenes of very low tacticity ([mmmm] = 12%).

C 1-Symmetric Si-bridged (2-indenyl)(1-indenyl) ansa -metallocenes as efficient ethene/1-hexene copolymerization catalysts

In the search for more efficient single-center ethene/α-olefin copolymerization catalysts, metallocenes bearing a 2-indenyl substituent pattern have largely been ignored in the past. Here, we show that such a structural motif yields competent linear low-density polyethylene (LLDPE) catalysts. They are also relatively easy to synthesize, allowing for a wide structural amplification. A screening of 28 catalysts reveals that the lead catalyst in this study displays high comonomer affinity and molecular weight capability at industrially relevant temperatures. QSAR models show that steric factors likely contribute stronger than electronic factors to the observed substituent trends, both for comonomer affinity and MW capability.

LIGANDS AND CATALYSTS FOR PRODUCING ELASTOMERIC PROPYLENE POLYMERS

A ligand useful to form a metallocene olefin polymerization catalyst comprises:wherein at least R3 and R4 are substituents having at least a bulk of a t-butyl group and, optionally, wherein R1 or R2 may be a bulky substituent group.