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Polymerization processes in Al(OBu s ) 3 sol‐gel solutions: an investigation by laser desorption/ionization mass spectrometry
Author(s) -
Zangrando Roberta,
Armelao Lidia,
Bottaro Gregorio,
Gross Silvia,
Seraglia Roberta,
Tondello Eugenio,
Traldi Pietro
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2642
Subject(s) - chemistry , condensation polymer , alkoxide , hydrolysis , solvent , polymerization , methanol , desorption , mass spectrometry , monomer , polymer chemistry , inorganic chemistry , catalysis , organic chemistry , polymer , chromatography , adsorption
The hydrolysis and polycondensation reactions of Al(OBu s ) 3 have been studied by laser desorption/ionization (LDI), performed on the solid samples originating from different aluminum alkoxide solutions, prepared using the usual operating conditions employed in the sol‐gel synthesis of Al 2 O 3 ‐based materials. CHCl 3 , CH 3 OH and CH 3 OH/H 2 O mixture were used as solvents. In the latter case different H 2 O/Al(OBu s ) 3 molar ratios were adopted, i.e. 1:1, 1:2, and 1:4. The obtained hydrolysis and polycondensation species consist of polynuclear species containing ≤12 aluminum atoms. In the CHCl 3 solutions, the formation of the observed hydrolysis products has been ascribed to the reaction with water present in the atmosphere during the LDI sample preparation and/or present at trace level in the solvent. When methanol is used as a solvent, extensive methanolysis reactions take place, thus originating oligomers with CH 3 O and OH substituents. The kinetics of formation of the various polynuclear species are dependent on the reaction environment and the reaction is faster in the presence of methanol. It is worth noticing that, regardless of the hydrolysis process, the polycondensation products can be considered as originating from a common tetrameric core [Al 4 O 4 (OBu) 2 (OH) 2 ] around which different building blocks are condensed to form various oxo‐polymeric species. Copyright © 2006 John Wiley & Sons, Ltd.