摘要
通过配体交换反应合成了膦化硅胶担载的羰基钴簇配合物(Si)—PPh_2[BrCCo_3(CO)_(9-2)],用IR、XPS和DPS对其结构进行了表征,并测得了担载簇配合物的金属含量,研究了担载簇(Si)—PPh_2[BrCCo_3(CO)_(9-2)]在烯烃氢甲酰化反应中的催化活性.结果表明,担载的三核羰基钴簇可达到与均相三核钴簇基本一致的反应活性,在一定的反应条件下,烯烃转化率和醇醛收率均在85％以上,有很少量的加氢产物生成。
Phosphino-silica-supported trinuclear cobalt carbonyl cluster has been synthesized by the ligand exchange reaction. The structure was characterized by IR, DRS, XPS. Infrared spectral studies have shown that the absorption bands which are in the range of 2076-2018 cm-1 appear for -PPh2 [BrCCO3(CO7)](Ⅰ) due to the stretching vibration of the terminal carbonyls, and resemble those of the unsupported BrCCo3(CO)9 (Ⅱ) (2105(m), 2041 (vs), 2028(s), 2008(s)). At 1874 cm-1, there is a band due to the bridging carbonyl. Di-substituted supported trinuclear cobalt carbonyl cluster with three bridged carbonyls seems to be formed from BrCCo3(CO)9on the phosphino-silica. From the DRS it is seen that the 6-6 peak of BrCCo3(CO)9at 375 nm, which is related to the Co-Co bond, was replaced by a peak at 380 nm which is the characteristic of cluster (Ⅰ) . The DRS reveals that the Co - Co bond character of the (Ⅰ) is essentially the same as that for the cluster (Ⅱ) in CH2C12.
The catalytic activity of (Ⅰ) for the hydroformylation of olefins and its mechanism have been investigated. The results show that the supported cluster has high activities and is comparable with that of the unsupported cluster (Ⅱ) . Under given conditions, the conversion of 1-heptene and the total yield of aldehydes and alcohols are over 85%. The product selectivity of aldehyde - alcohol is over 95% and only a small amount of hydrogenation products is formed.
出处
《分子催化》
EI
CAS
CSCD
1992年第2期128-135,共8页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金资助项目
关键词
钴簇
金属
担载
催化剂
氢甲酰化
Supported catalyst, Cluster, Hydroformylation, Olefin.
