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Characterization of Aluminoxanes by ESR Spin Probe Method
Author(s) -
Wang Qi,
Zhao Yan,
Song Lixin,
Fan Zhiqiang,
Feng Linxian
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010201)202:3<448::aid-macp448>3.0.co;2-w
Subject(s) - alkyl , chemistry , electron paramagnetic resonance , aluminium , lewis acids and bases , crystallography , polymer chemistry , characterization (materials science) , spin (aerodynamics) , stereochemistry , nuclear magnetic resonance , organic chemistry , materials science , nanotechnology , catalysis , physics , aerospace engineering , engineering
Abstract Lewis acidic sites of MAO, EBAO and EAO were studied by the ESR method with TEMPO as a spin probe. The ESR studies on MAO, EBAO and EAO indicated that different aluminum atoms coexist in aluminoxanes. More Lewis acidic three‐coordinated aluminum atoms were found in EBAO than in MAO and EAO. This obvious difference was attributed to the more irregular structure of EBAO due to stereochemical effects. The different alkyl groups, namely ethyl and iso‐butyl groups in EBAO, can greatly disturb the regular structure of aluminoxane which lead to the formation of more unsaturated aluminum atoms and enhanced activity of EBAO as compared with EAO and BAO.