Novel Chiral PNNP-Ru Complexes: Synthesis and Application in Asymmetric Transfer Hydrogenation of Ketones

The efficient catalytic systems generated in situ from RuCl(2)(PPh(3))(3) and chiral ligands N,N-bis[2-(di-o-tolylphosphino)-benzyl]cyclohexane-1,2-diamine(2) were employed for asymmetric transfer hydrogenation of aromatic ketones, giving the corresponding optically active alcohols with high activities(up to 99% conversion) and excellent enantioselectivities(up to 96% e.e.) undcr mild conditions. The chiral ruthenium(II) complex (R,R)-3 has been prepared and characterized by NMR and X-ray crystallography.National Natural Science Foundation of China[20423002, 20703034]; Natural Science Foundation of Fujian Province of China[2008J0235]; Natural Science Foundation of Guangxi Province of China[0991016

Vapor Phase Carbonylation of Ethanol over Ni-M(M=Cu, Zn, Ce)/C Catalysts

A series of NiM0.2(M=Cu, Zn, Ce)/C and Ni/C catalysts were prepared by isometric impregnation method for vapor phase carbonylation of ethanol. The activity testing results revealed that the activity of four catalysts was in the order of NiCe0.2/C>Ni/C>NiCu0.2/C>NiZn0.2/C, and the NiCe0.2/C catalyst showed maximum catalytic activity for carbonylation of ethanol with the ethanol conversion of 98.0% and the propionic acid selectivity of 95.1% in comparison with other catalysts, but the NiZn0.2/C catalyst showed minimum activity with the ethanol conversion of 83.6% and the propionic acid selectivity of 75.8%. The catalysts were characterized by means of metal dispersion test, XRD, H-2-TPR and CO-TPD. It was found that a certain interaction between ceria and nickel species was confirmed to level the reduction temperature of nickel oxide down, avoiding effectively from bigger nickel crystallites, thereby increasing the metal dispersion of nickel species on the Surface of active carbon