摘要
用Rh_2(CO)_4Cl_2与水杨醛肟的钠盐反应合成了二羰基水杨醛肟铑配合物Bh(sox)(CO_2)(1)。在常压下研究了该配合物与膦或亚磷酸酯组成的体系对苯乙烯氢甲酰化反应的催化性能,此体系对烯烃没有催化加氢作用,产物醛的化学选择性均为100％。考察了膦的结构与用量对催化活性和选择性的影响,双膦作配体时活性和选择性都高于单膦,其中Rh(sox)(CO)_2-Ph_2P(CH_2)_3PPh_2体系的最高初活性(TON)可达1.60min^(-1),2-苯基丙醛的选择性在90％以上。对反应的活性物种作了初步讨论。
Dicarbonyl salicylaldoximate rhodium complex(1)was prepared from [Rh(CO)_2Cl]_2 and the sodium salt of salioylaldoxime. The complex has been proved to be a very active catalyst precursor in the presence of phosphines for the hydroformylation of styrene under 0.1 MPa and 60℃. The results show that both the activity and selectivity increase as the phosphine ligands are changed from the monophosphine to diphosphines. In the presence of 1, 3-bis(diphenylphosphino) propane, an optimum catalyst activity (TON; of 1.6 min^(-1) can be achieved and the regioselectivity for 2 -phenylpropanal is up to 90％. The sequence of phosphines for the regioselectivity of 2-phenylpropanal is in good accordance with their σ-electron donating abilities. That, is, Ph_2P(CH_2)_3PPh_2≈Ph_2P(CH_2)_2PPh_2>PPh_3>P(OPh)_3. An increase in the P/Rh ratio, except for PPh_3 as ligands, leads to a decrease in catalyst activity, but a small excess of phosphines favors the stability of the catalyst and the P/Rh ratio does not allect the regioseleotivity remarkably. No side reactions such as hydrogenation have been found, the chemoselectivity of aldehyde is 100％.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1992年第6期601-606,共6页
Acta Chimica Sinica
基金
国家自然科学基金
