Continuous solution copolymerization of ethylene with propylene using a constrained geometry catalyst system

Park, Shin-Joon; Wang, Wenjun; Zhu, Shiping

doi:10.1002/1521-3935(20001101)201:16<2203::aid-macp2203>3.0.co;2-v

Cited by 15 publications

(7 citation statements)

References 14 publications

(30 reference statements)

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“…These apparent reactivity ratios have high uncertainty and indicate a slight preference for octene to follow an ethene insertion and for ethene to follow an octene insertion (Scheme ). Such apparent reactivity ratios indicate a much higher comonomer (1-octene) incorporation than many of the metallocene or F1-type catalysts, and these values are similar to the constrained geometry catalysts (CCGs). ,− …”

Section: Resultsmentioning

confidence: 68%

The Hafnium-Pyridyl Amido-Catalyzed Copolymerization of Ethene and 1-Octene: How Small Amounts of Ethene Impact Catalysis

Cueny

Landis

2019

ACS Catal.

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Copolymerization of ethene and 1-octene is catalyzed by the Hf-pyridyl amido complex used in chain-shuttling polymerization. Active site counts and the molar mass distribution of catalyst-bound polymeryls are determined by chromophore quench-labeling. Catalytic data for copolymerization (1-octene consumption, active site counts, molar mass distributions of polymers, and I2-labeling of Zn-polymeryls) are compared with similar data for the homopolymerization of 1-octene. Such comparisons reveal that small amounts of ethene have a significant impact on catalysis. The rate of 1-octene consumption increases in a copolymerization ∼3-fold compared to a homopolymerization; this likely results from in situ ligand modification. The first insertion of alkene occurs into the Hf–naphthyl bond of the Hf-pyridyl amido catalyst; in copolymerization, competition between ethene and 1-octene for this insertion creates multiple active species. We propose that ethene insertion into the Hf–naphthyl bond leads to a faster polymerization catalyst than insertion of 1-octene. In the presence of diethyl zinc, the homopolymerization of 1-octene produces broader molar mass distributions than those seen for the copolymerization of octene and ethene. Narrowing of the distribution by ethene presumably reflects increased reversibility of chain transfer between Hf and Zn. I2-labeling of Zn-polymeryls and subsequent NMR chain end analysis reveals that more than one polymer chain per Zn is produced under copolymerization conditions. The steric requirements for reversible chain transfer are assessed by I2-labeling of “sequential” copolymerization reactions.

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Section: Resultsmentioning

confidence: 68%

The Hafnium-Pyridyl Amido-Catalyzed Copolymerization of Ethene and 1-Octene: How Small Amounts of Ethene Impact Catalysis

Cueny

Landis

2019

ACS Catal.

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“…16 Our obtained value of r 1-decene = 0.49 is also notably larger than that reported for 1-octene with the Dow-Exxon CGC 1/MAO (r ethylene = 7.90 and r 1-octene = 0.10) 17 and even that reported for propylene with 1/MAO (r ethylene = 4.33 and r propylene = 0.38). 18 Adding to the impressive behavior…”

Section: Reactivity Ratios For Ethylene/1-decene Polymerization With ...mentioning

confidence: 99%

Sterically expanded CGC catalysts: substituent effects on ethylene and α-olefin polymerization

2013

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Several analogues of the sterically expanded constrained geometry catalyst Me2Si(η(1)-C29H36)(η(1)-N-tBu)ZrCl2·OEt2 (2) were synthesized to assess the effect on branching and molecular weight for ethylene homopolymerization. Catalysts based on tetramethyltetrahydrobenzofluorene (TetH), ethylTetH, t-butylTetH, and octamethyloctahydrodibenzofluorenyl (OctH) bearing a diphenylsilyl bridge were prepared and characterized: Me2Si(η(5)-C21H22)(η(1)-N-tBu)ZrCl2 (3); Me2Si(η(5)-C23H26)(η(1)-N-tBu)ZrCl2 (4); and Me2Si(η(5)-C25H30)(η(1)-N-tBu)ZrCl2 (5); Me2Si(η(5)-C21H22)(η(1)-N-tBu)ZrMe2 (6); and Ph2Si(η(5)-C29H36)(η(1)-N-tBu)ZrCl2 (7). Complexes 4, 5, 6, and 7 were characterized by X-ray crystallography and displayed η(5) hapticity to the carbon ring in each case, in contrast to 2. In comparison to 2, complexes 3, 4, 5, and 7 (in combination with methylaluminoxane = MAO) showed diminished branching, higher molecular weight, and higher polydispersity indices for obtained ethylene homopolymers. While 4/MAO produced the greatest molecular weight polymers, no branching was observed. Reactivity ratios were determined for the copolymerization of ethylene and 1-decene with 2/MAO. A value of r(ethylene) = 14.9 and an exceedingly high value of r(1-decene) = 0.49 were found--in line with previous reports of this catalyst's unusual affinity for α-olefins.

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“…First, EPR macromonomers were prepared in a high‐temperature, high‐pressure continuous stirred tank reactor using a Dow Chemical constrained geometry catalyst, [C 5 Me 4 (SiMe 2 N t Bu)]TiMe 2 with cocatalyst, tris(pentafluorophenyl)boron. The details regarding the reactor system and the polymerization were reported in previous publications 20, 21. Next, the EPR macromonomers were copolymerized with propylene in a semibatch reactor using rac ‐dimethylsilylenebis(2‐methylbenz[e]indenyl) zirconium dichloride and modified methyl aluminoxane.…”

Section: Methodsmentioning

confidence: 99%

Differential scanning calorimetry of copolymer of isotactic polypropylene backbone with grafted poly(ethylene‐co‐propylene) branches

Whitney¹,

Zhu²

2006

J of Applied Polymer Sci

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A series of graft polymers having polypropylene (PP) backbone and poly(ethylene-co-propylene) (EPR) side chains was prepared. PP backbone molecular weight (M n ) was 28 -98 kg/mol, EPR side chain M n was 2.6 -17 kg/mol, and EPR content was 0 -16 wt %. In this work, thermal analysis of the copolymers was performed using differential scanning calorimetry (DSC). Nonisothermal crystallization was performed at different cooling rates. The DSC thermograms revealed multiple melting peaks for slowly cooled samples, most likely the result of the melting of thinner tangential lamellae followed by the melting of thicker radial lamellae. Equilibrium melting temperature (T m 0 ) was determined using the linear Hoffman-Weeks method. Another approach was also used for determining

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Continuous solution copolymerization of ethylene with propylene using a constrained geometry catalyst system

Cited by 15 publications

References 14 publications

The Hafnium-Pyridyl Amido-Catalyzed Copolymerization of Ethene and 1-Octene: How Small Amounts of Ethene Impact Catalysis

The Hafnium-Pyridyl Amido-Catalyzed Copolymerization of Ethene and 1-Octene: How Small Amounts of Ethene Impact Catalysis

Sterically expanded CGC catalysts: substituent effects on ethylene and α-olefin polymerization

Differential scanning calorimetry of copolymer of isotactic polypropylene backbone with grafted poly(ethylene‐co‐propylene) branches

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