INFRARED OBSERVATION OF THE CHEMICAL CONSEQUENCES OF COBALT CATALYST PRODUCED IN MIXED-SOLUTIONS OF AL(ET)(3) AND CO(ACAC)(2)

被引:7
作者
BARRAULT, J
BLANCHARD, M
DEROUAULT, A
KSIBI, M
ZAKI, MI
机构
[1] Laboratoire de Catalyse, URA-CNRS 350, ESIP, 86022 Poitiers Cedex
来源
JOURNAL OF MOLECULAR CATALYSIS | 1994年 / 93卷 / 03期
关键词
ACETYLACETONATE COMPLEXES; COBALT; FT-IR SPECTROSCOPY; REDUCTION; TRIETHYLALUMINUM;
D O I
10.1016/0304-5102(94)87001-2
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
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 degrees 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.
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页码:289 / 304
页数:16
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