Nitrogen-linked diphosphine ligands with ethers attached to nitrogen for chromium-catalyzed ethylene tri- and tetramerizations
Nitrogen-linked diphosphine ligands with ethers attached to nitrogen for chromium-catalyzed ethylene tri- and tetramerizations
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DOI：
10.1021/om0601596
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发表时间：
2006-10-23
期刊：
影响因子：
2.8
通讯作者：
Bercaw, John E.
中科院分区：
文献类型：
--
作者：
Elowe, Paul R.;McCann, Cassandra;Bercaw, John E.
制备了一系列双（二苯基膦）胺配体，其给体基团与氮连接。这些配体与三氯化铬的金属化为乙烯的三聚化和四聚化提供了高活性、相对稳定和选择性催化剂的前体。与二膦配体上缺乏给体基团的体系相比，在1和4 atm的乙烯低聚化反应中已经证明，这些新体系通过增强催化剂稳定性来提高总生产率。此外，使用氯苯溶剂（而不是甲苯）可显著提高生产率、稳定性和选择性。产品分布和次要副产物提供了与这些类型的反应有关的机械问题的信息。
A series of bis(diphenylphosphino) amine ligands with a donor group attached to the nitrogen linker have been prepared. Metalation of these ligands with chromium trichloride provides precursors to highly active, relatively stable, and selective catalysts for trimerization and tetramerization of ethylene. It has been demonstrated in oligomerization reactions performed at 1 and 4 atm of ethylene that these new systems increase total productivity by enhancing catalyst stability, as compared with those lacking a donor group on the diphosphine ligand. Furthermore, the use of chlorobenzene solvent ( rather than toluene) significantly improves productivity, stability, and selectitvity. The product distributions and minor byproducts provide information relevant to mechanistic issues surrounding these types of reactions.