摘要/Abstract
基于不同电子和空间效应的膦配体L1~L4, 合成了一系列新型铱配合物Ir-L1~Ir-L4, 考察了配体在铱配合物催化水作氢源的氢甲酰化反应中的影响. 研究表明, 具有较强π-受电子能力的离子型双齿膦配体L4 (1J31P-77Se =781 Hz)修饰的铱配合物可以同时促进水煤气变换反应和烯烃氢甲酰化反应: 以Ir-L4配合物为催化剂, 1-己烯的转化率高达93%, 产物醛(直链醛和支链醛)的收率为93%, 1-己烯加氢副产物己烷的收率小于1%, 表明水作氢源几乎完全抑制了烯烃加氢副反应. 此外, Ir-L4催化体系结合离子液体([MePh3P]Br)还可实现催化剂的回收循环5次.
关键词: 离子型膦配体, 铱配合物, 氢甲酰化反应, 水煤气变换反应
A series of novel Ir-complexes, namely Ir-L1, Ir-L2, Ir-L3 and Ir-L4, where L1~L4 represent phosphine ligands having different electronic and steric effects, were synthesized in this work. Then the effect of the as-synthesized phosphine ligands on the performance of the Ir(I)-complexes catalysts was investigated for the hydroformylation reaction using H2O as the hydrogen source. It was found that the Ir-complex modified by the ionic bi-dentate phosphines L4 with a strong π-accepting ability (1J31P-77Se =781 Hz) can effectively promote water gas shift reaction (WGSR) and hydroformylation of olefins at the same time. As a result, a 1-hexene conversion of 93% was obtained, and the total yields of the target (linear and branched) aldehydes were up to 93% when using the Ir-L4 catalyst. Meanwhile, the yield of hexane from the hydrogenation of 1-hexene was less than 1%, showing that the side reaction of olefin hydrogenation can be almost completely inhibited when using H2O as the hydrogen source. Moreover, by using the ionic liquid of [MePh3P]Br as the solvent, Ir-L4 catalyst can be efficiently recovered for at least 5 times.
Key words: ionic phosphines, iridium complexes, hydroformylation, water gas shift reaction
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