摘要
聚苯乙烯(PS)是匀相催化剂多相化研究中常用的高分子载体,但通常涉及的均是交联聚苯乙烯(CPS)。本文制备了不同链长的直链聚苯乙烯(LPS)负载钯催化剂(LPSN-Pd);将其与相应的交联聚苯乙烯负载的钯催化剂(CPSN-Pd)对比,考察了这类催化剂对不饱和烃类加氢反应的活性、选择性以及起始载体链长对催化刑加氢性能的影响。
The activities and selectivities of supported Pd catalysts prepared by coordinating PdCl2 on functionalized linear polystyrenes ( LPSN ) with various molecular weights were studied and compared with those of the catalyst supported on the cross-Linked polystyrene ( CPSN-Pd ).
The LPSN-Pd are good catalysts for 1-hexene hydrogenation. The molecular weight of the supports has little effect on the catalyst activity when it lies between 1,000 to 77,000. But the catalyst gives a lower activity if the value is increased to 120,000, the CPSN-Pd exhibits higher activity than the LPSN-Pd. The difference between these two kinds of catalysts comes from the different characteristics of supports. The catalysts of LPSN-Pd are no longer soluble and their specific surface areas are very small ( 1 m2/g ) . It is noticeable that they swell strongly in the reaction medium although the swelling capacity of the LPSN-Pd prepared from LPS with higher molecular weight is slightly lower. The cross-linked polystyrene (CPS, 10% crosslink ) is a porous material with a specific surface area of 150 m2/g. Thus, not only the porous materials, but also the polymer with strong swelling behavior can be used as the supports. Irregular entangling of polymer chain may decrease the activity of the corresponding catalyst. The kinetic curves of olefine hydrogenation by using these catalysts are quite similar. These catalysts show good stability in the olefine hydrogenation and can be repeatedly used without obvious decrease in activity. For the hydrogenation of 1-hexyne or cyclopentadiene, these catalysts display high selectivity for mono-olefines. The higher coordination abilities of 1-hexyne or cyclopentadiene than that of the corresponding momolefines is the cause for the high selectivities of the catalysts.
出处
《分子催化》
EI
CAS
CSCD
1991年第4期362-366,共5页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金
