Characterization of alumoxanes by 27Al-NMR spectra

Sugano, Toshihiko; Matsubara, Koshi; Fujita, Takashi; Takahashi, Toshihiro

doi:10.1016/0304-5102(93)80074-5

Cited by 51 publications

(46 citation statements)

References 13 publications

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“…This resonance was also observed by Nekhaeva et al, 4 while not observed by Sugano et al 5 and Mason et al 6 The chemical shift of TMA is approximately 154 ppm, which confirms the result reported by Sugano et al 5 and Mason et al 6 …”

Section: Tmasupporting

confidence: 92%

“…The line widths of the in situ partially hydrolyzed products of TMA with water are narrower than that reported by Sugano et al, 5 and vary slightly with reaction time within a short period of time, which means that the molecular weights are low and nearly the same. But after 19 h, it increases a bit, mainly due to the increase of its molecular weight after a long time.…”

Section: Al-nmr Study Of In Situ Hydrolysis Reaction Of Tma With Watermentioning

confidence: 72%

“…Sugano et al 5 showed that the 27 Al chemical shift of MAO was approximately 154 ppm, which was due to the tetra-coordinated structure. They also found that the line width of MAO increased with the molecular weight of MAO.…”

Section: Al-nmr Study Of In Situ Hydrolysis Reaction Of Tma With Watermentioning

confidence: 98%

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In situ1H- and27AL-NMR studies on metallocene catalyst systems?Catalysts for olefin polymerization

Zhang¹,

Duan²,

Zheng³

et al. 2000

J. Appl. Polym. Sci.

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ABSTRACT:The process of partial hydrolysis reaction of TMA with water and the interaction of zirconocene dichloride (Cp 2 ZrCl 2 ) with TMA, MAO, and the in situ partially hydrolyzed products of TMA were studied by in situ Al-NMR spectroscopy. The 1 H-NMR spectra of MAO samples and the in situ hydrolyzed products of TMA with water under different conditions are different. A new peak at ␦ ϭ Ϫ0.58 ppm in 1 H-NMR spectra is observed, and is supposed to be due to the methyl resonance of MAO with low molecular weight. Alkylation reaction is observed between Cp 2 ZrCl 2 and TMA, MAO, and the in situ hydrolyzed products of TMA, and TMA is supposed to be the actual alkylating agent.27 Al-NMR studies show that MAO is tetra-coordinated.

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Section: Tmasupporting

confidence: 92%

Section: Al-nmr Study Of In Situ Hydrolysis Reaction Of Tma With Watermentioning

confidence: 72%

See 1 more Smart Citation

In situ1H- and27AL-NMR studies on metallocene catalyst systems?Catalysts for olefin polymerization

Zhang¹,

Duan²,

Zheng³

et al. 2000

J. Appl. Polym. Sci.

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show abstract

“…4,6,[12][13][14][15] Unfortunately, the peaks attributed to MAO in 1 H, 13 C, 17 O, and 27 Al NMR spectra are very broad and almost featureless. It has been concluded from 27 Al and 17 O NMR investigations that the main coordination numbers of aluminum and oxygen in MAO are 4 and 3, respectively.…”

Section: Characterization Of Maomentioning

confidence: 99%

“…10,17 Methyl-bridged double chains have been suggested by Sugano et al, 15 but such linking should be highly unfavorable compared with AlOO linking.…”

Section: Structure Modelsmentioning

confidence: 99%

Experimental and theoretical investigations of the structure of methylaluminoxane (MAO) cocatalysts for olefin polymerization

Ystenes

Eilertsen

Liu

et al. 2000

J. Polym. Sci. A Polym. Chem.

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Partially hydrolyzed trimethylaluminum (PHT) as heterogeneous cocatalyst for the polymerization of olefins with metallocene complexes

Köppl

Alt

Phillips

2001

J. Appl. Polym. Sci.

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A method for the preparation of a novel heterogeneous cocatalyst, partially hydrolyzed trimethylaluminum (PHT), has been developed and optimized for ethylene polymerization reactions. It is possible to generate PHT on nearly any support without much loss of catalyst activity. The carrier material can be SiO2, AlF3, B2O3, starch, cellulose, active carbon, polyethylene, polypropylene, polystyrene, etc. This new type of partially hydrolyzed trimethylaluminum (PHT) is synthesized by reacting such a carrier material with trimethylaluminum (TMA) in toluene to block all surface Lewis basic centers that could poison a cationic metallocene polymerization center. The subsequent addition of a calculated amount of water gives a heterogeneous PHT that is different from the common methylalumoxane (MAO). Various PHT cocatalysts were studied by 13C and 27Al MAS NMR, scanning electron microscopy (SEM), and infrared spectroscopy (IR), and compared with solid MAO. Surface areas and porosities were determined according to the BET method. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 454–466, 2001

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Characterization of alumoxanes by 27Al-NMR spectra

Cited by 51 publications

References 13 publications

In situ1H- and27AL-NMR studies on metallocene catalyst systems?Catalysts for olefin polymerization

In situ1H- and27AL-NMR studies on metallocene catalyst systems?Catalysts for olefin polymerization

Experimental and theoretical investigations of the structure of methylaluminoxane (MAO) cocatalysts for olefin polymerization

Partially hydrolyzed trimethylaluminum (PHT) as heterogeneous cocatalyst for the polymerization of olefins with metallocene complexes

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