Infrared observation of the chemical consequences of cobalt catalyst produced in mixed solutions of Al(Et) 3 and Co(acac) 2

• Published in: Journal of molecular catalysis Vol. 93; no. 3; pp. 289 - 304
• Main Authors: Barrault, J., Blanchard, M., Derouault, A., Ksibi, M., Zaki, M.I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 27.10.1994
• Subjects: Acetylacetonate complexes; Cobalt; FT-IR spectroscopy; Reduction; Triethylaluminium; Triethylaluminium; Acetylacetonate complexes; Reduction; FT-IR spectroscopy; Cobalt
• ISSN: 0304-5102
• DOI: 10.1016/0304-5102(94)87001-2

Cobalt catalysts obtained from the reduction of Co(acac) 2 with Al(Et) 3 have been studied by infrared spectroscopy (in the selective hydrogenation of multifunctional compounds). These solids prepared in situ were in suspension in a liquid mixture containing solvent and reagent. In order to obtain information on the preparation and the composition of the catalyst we carried out an FT-IR characterization using a special device warranting sample manipulation in air-free atmosphere. At room temperature there were instantaneous and reductive ligand-exchange between Al(Et) 3 and Co(acac) 2 and formation of Co 0 particles, Co 0 soluble complexes and Al(Et) 2(acac). The multistep process may be initiated through the formation of a donor-acceptor complex ((acac)Co(acac)→Al(Et) 3). The presence of CO in the gas phase (H 2) when heating the reaction mixture up to 180°C enhances the reduction of cobalt and probes Co 0 in different coordination symmetries. Some of the Co 0 species could be surrounded with cobalt alkoxide species and aluminium acetylacetonate.