Structure and Performance of the Solid Methylalumoxane at Temperatures 20–250°C: Experimental and DFT Calculation Study Full article
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Journal of Molecular Catalysis A: Chemical
ISSN: 1381-1169 |
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| Output data | Year: 2001, Volume: 174, Number: 1-2, Pages: 107-117 Pages count : 11 DOI: 10.1016/S1381-1169(01)00190-X | ||
| Tags | Metallocene catalyst, Methylalumoxane structure | ||
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Abstract:
The structure of solid methylalumoxane (MAO) and its behavior in the temperature interval from 20 to 250°C have been studied using IR spectroscopy in diffusion reflection mode (DRIFT) and mass-spectrometric (MS) methods. It has been shown that three-dimensional MAO molecule may entrap water molecule in its volume (absorption bands (a.b.) 3550 cm−1 in the IR-spectrum). Using a density functional theory (DFT) quantum-chemical method, the three-dimensional molecular model of MAO with composition (Al(CH3)O)12, comprising water molecule in its structure, has been calculated. The release of the water molecule from the structure of MAO molecule is accompanied by the protolysis of AlCH3 bonds and methane evolving. This reaction seems to be responsible for the observed evolving of methane on the MAO aging. As the temperature of MAO heating increases from 20 to 150°C, the process of methane evolving intensifies.
The heating of the solid MAO samples is also accompanied by the release of trimethylaluminum (TMA) in significant amount (0.18 mole AlMe3/mole AlMAO at 100°C). Obviously, the released TMA was strongly associated with the MAO in the initial sample.
The data on the activity in the ethylene polymerization of catalyst Cp2ZrCl2/MAO prepared with the use of the MAO samples dried at temperatures 20–250°C are presented as well.
Cite:
Panchenko V.N.
, Zakharov V.A.
, Danilova I.G.
, Paukshtis E.A.
, Zakharov I.I.
, Goncharov V.B.
, Suknev A.P.
Structure and Performance of the Solid Methylalumoxane at Temperatures 20–250°C: Experimental and DFT Calculation Study
Journal of Molecular Catalysis A: Chemical. 2001. V.174. N1-2. P.107-117. DOI: 10.1016/S1381-1169(01)00190-X WOS Scopus РИНЦ ANCAN OpenAlex
Structure and Performance of the Solid Methylalumoxane at Temperatures 20–250°C: Experimental and DFT Calculation Study
Journal of Molecular Catalysis A: Chemical. 2001. V.174. N1-2. P.107-117. DOI: 10.1016/S1381-1169(01)00190-X WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
| Submitted: | Aug 8, 2000 |
| Accepted: | Mar 8, 2001 |
| Published online: | Sep 19, 2001 |
| Published print: | Oct 1, 2001 |
Identifiers:
| Web of science: | WOS:000171354800013 |
| Scopus: | 2-s2.0-0035478224 |
| Elibrary: | 13377469 |
| Chemical Abstracts: | 2001:694026 |
| Chemical Abstracts (print): | 136:70116 |
| OpenAlex: | W117697797 |