Co-PPh3@ POPs heterogeneous catalysts for hydroformylation of olefins
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Abstract
Hydroformylation is widely used to produce aldehydes or alcohols by the addition of syngas to olefins,which is catalyzed by transition metal complexes. Although homogeneous catalysts exhibit an excellent activity under mild re- action conditions,its industrial application on a large scale is hindered by the separation of the catalyst from the prod- uct. The prominent advantage of a heterogeneous catalyst is its easy separation from the product in contrast to a homo- geneous catalyst. However,heterogeneous catalysts suffer the problem of low activity or selectivity. Extensive research has been devoted to developing heterogenized homogeneous catalysts which combine the practical advantages of heterogeneous catalysts with the high efficiency of homogeneous catalysts. Rh is the most catalytic active for the hydroformy- lation of olefins. Although the catalytic active for Co is relatively low,the application of Co for hydroformylation has some industrial values. Noble metal Rh is the scarce resource and high cost,therefore,this paper studied the Co based heterogeneous hydroformylation of olefins. The Co-PPh3 @ POPs heterogeneous catalyst was prepared for the hydro- formylation of olefins. The influence of solvent,Co precursors,Co loading and reaction time on the activity of hydro- formylation over the Co-PPh3 @ POPs catalysts were investigated in detail. Toluene solvent,Co( OAc)2 and 10% Co loading were the optimal conditions for Co-PPh3 @ POPs catalysts. It showed higher activity than other inorganic carri- ers supported Co based heterogeneous catalysts such as Co@ SiO2 and Co@ SBA-15. Thermogravimetry,N2 adsorption, scanning electron microscopy and transmission electron microscopy indicated the Co-PPh3 @ POPs catalyst featured su- perior thermal stability,high surface areas,hierarchical porosity and highly uniform dispersed Co species.
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