Butadiene polymerization with various half-titanocenes

Ikai, Shigeru; Yamashita, Jun; Kai, Yoshiaki; Murakami, Masato; Yano, Takefumi; Qian, Yanlong; Huang, Jiling

doi:10.1016/s1381-1169(98)00227-1

Cited by 20 publications

(5 citation statements)

References 18 publications

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“…Metallocene catalysts activated by methylaluminoxane (MAO) give homogeneous systems, leading to extensive control of the M w / M n and steric structure of polymers in the polymerization of ethylene, α‐olefins, and styrene. Triggered by those remarkable results, a variety of catalysts composed of transition‐metal (e.g., Ti,8–14 V,12, 15–17 Cr,18, 19 Co,12, 20–22 Ni,23–28 Nd,7, 12, 29–34 and Sm35, 36) compounds and MAO were examined in 1,3‐diene polymerization. In the polymerization of 1,3‐butadiene, the use of MAO in place of AlR 3 as a cocatalyst generally affects both the catalytic activity and stereospecificity of the transition‐metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

Novel neodymium (III) isopropoxide‐methylaluminoxane catalyst for isoprene polymerization

Dong

Masuda

2002

J. Polym. Sci. A Polym. Chem.

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A novel catalyst composed of neodymium (III) isopropoxide [Nd(OiPr) 3 ] and methylaluminoxane (MAO) was examined in isoprene polymerization. The Nd(OiPr) 3 -MAO catalyst proved to be highly effective in heptane even at low [Al]/[Nd] ratios (ca. 30) to give polyisoprene that possessed high cis-1,4 stereoregularity (Ͼ ca. 90%), a high number-average molecular weight (M n ϳ10 5 ), and relatively narrow molecular weight distributions (M w /M n ϭ 1.9 -2.8). The catalyst activity increased with an increasing [Al]/[Nd] ratio from 10 to 80 as well as temperature of aging and polymerization from 0 to 60°C. The polymerization proceeded in the first order with respect to the monomer concentration. Aliphatic solvents (heptane and cyclohexane) achieved a higher yield and M n of polymer than toluene as a solvent. The M w /M n ratio remained around 2.0, and the gel permeation chromatographic curve was always unimodal, indicating that this system is homogeneous and involves a single active site. The microstructure of polyisoprene was determined by IR, 1 H NMR, and 13 C NMR. The cis-1,4 contents of the final polymers stayed in the range of 90 -92%, regardless of reaction conditions, indicating the high stability of stereospecificity of the catalyst.

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Section: Introductionmentioning

confidence: 99%

Novel neodymium (III) isopropoxide‐methylaluminoxane catalyst for isoprene polymerization

Dong

Masuda

2002

J. Polym. Sci. A Polym. Chem.

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“…12 The steric properties of the ligand also affect the catalyst activity. 13 This effect is related to the yield of an active catalyst form described by the reactions in Eqns In reaction [1] CpTiX 3 is alkylated to CpTiMe 3 , which in the second step undergoes a homolytic reductive dissociation to CpTiMe 2 . In this next step titanium(IV) is reduced to titanium(III) (this can also be accelerated by new MAO(X)).…”

Section: Discussionmentioning

confidence: 99%

Syndiotactic polymerization of styrene in the presence of CpTiCl₂(OC₆H₄X)/MAO catalytic systems

Skupiński

Niciński

2001

Applied Organom Chemis

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CpTiCl 2 (OC 6 H 4 X-p) complexes (where X = CH 3 , Cl, NO 2 ,; Cp = cyclopentadienyl) activated with methylaluminoxane (MAO) were used in syndiotactic polymerization of styrene. High activity and selectivity for all catalysts were found. The styrene conversion and reaction selectivity depend on the catalyst ageing time and temperature, polymerization temperature and the nature of the substituent in the phenoxy ring.

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“…The activity trend is in line with the order of Ti-O-C angle of the complex, possibly because the more open angle favors the coordination of monomer to the metal center [3] . On the other hand, Cp*-based complexes 2c and 2d exhibited lower activities than their Cp-based counterparts 2a and 2b, which might be owing to the steric hindrance [9] . These complexes exhibited somewhat low selectivity which was similar to that of traditional half-titanocene; the cis-1,4 contents ranged from 72.9% to 80.5%.…”

Section: Polymerization Of 13-butadienementioning

confidence: 93%

Living polymerization of 1,3-butadiene catalyzed by half-titanocene complex bearing dibenzhydryl-substituted aryloxide ligand

et al. 2017

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Half-titanocene complexes bearing dibenzhydryl-substituted aryloxide ligands (2a−2d) were prepared. Among them, 2c adopted a three-legged distorted tetrahedral geometry evidenced by X-ray crystallography. The poly-1,3-butadiene with high molecular weight and narrow molecular weight distribution was obtained by using these complexes as the catalysts activated with methylaluminoxane (MAO). The catalytic activities of the complexes depended on their structures. The Ti-O-C bond in the complexes with large angle afforded them with higher activity, while Cp*-based complexes exhibited lower activities than the Cp-based analogues. The activity of complex increased with increasing the polymerization temperature while the selectivity remained no change, indicating the high thermal stability. Furthermore, the polymerization of 1,3-butadiene catalyzed by 2a/MAO at 0 °C has been found in a living fashion.

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Butadiene polymerization with various half-titanocenes

Cited by 20 publications

References 18 publications

Novel neodymium (III) isopropoxide‐methylaluminoxane catalyst for isoprene polymerization

Novel neodymium (III) isopropoxide‐methylaluminoxane catalyst for isoprene polymerization

Syndiotactic polymerization of styrene in the presence of CpTiCl₂(OC₆H₄X)/MAO catalytic systems

Living polymerization of 1,3-butadiene catalyzed by half-titanocene complex bearing dibenzhydryl-substituted aryloxide ligand

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Butadiene polymerization with various half-titanocenes

Cited by 20 publications

References 18 publications

Novel neodymium (III) isopropoxide‐methylaluminoxane catalyst for isoprene polymerization

Novel neodymium (III) isopropoxide‐methylaluminoxane catalyst for isoprene polymerization

Syndiotactic polymerization of styrene in the presence of CpTiCl2(OC6H4X)/MAO catalytic systems

Living polymerization of 1,3-butadiene catalyzed by half-titanocene complex bearing dibenzhydryl-substituted aryloxide ligand

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Syndiotactic polymerization of styrene in the presence of CpTiCl₂(OC₆H₄X)/MAO catalytic systems