Synthesis,Characterization Of Zirconium Phosphonate Immobilized Chiral Amino Alcohol And Its Application In Heterogeneous Asymmetric Catalysis

In this paper, the readily avilable chiral (1R, 2S)-(-)-2-aminol, 2-diphenylethanol and (1S, 2R)-(+)-2-amino-1, 2-diphenylethanol had been immobilized on the frame of layered zirconium phosphonates by three steps of nucleophilic substitution, hydrolysis and depozation. The composition, structure and surface morphology of the catalysts were characterized by IR, ³¹P NMR, TG, XRD and SEM. SEM and XRD data showed that the catalyst (1S, 2R)-(+)-101b was in layered and pore structure with the interlayer spacing 24.7983 A. The addition of Et₂Zn to benzadehyde was used to study the catalysis activity of the chiral catalyst zirconium phosphonates. The 80.1 % yield and 54.3 % e.e enantioselectivity of optical secondary alcohol were obtained at room temperature for 72 h in tolune. The enantioselectivity decrease at only 7.6 % enantio-meric excess lower than the corresponding chiral ligand (1R, 2S)-(-)-99b in homogeneous asymmetric catalysis. The zirconium phosphonate catalysts was easily recovered and reused.