TAILIEUCHUNG - Synthesis of polymer brushes from salen ligand/silica and its application as catalyst for the hydrolytic kinetic resolution of epichlorohydrin
The corresponding cobalt complex of the polymer brusches was used as a highly efficient recyclable catalyst for the hydrolytic kinetic resolution of racemic mixture of epichlorohydrin. The reaction was carried out under solvent-free condition at room temperature in the presence of mol% of cobalt, with enantiomeric excess (ee) of higher than 99% and a conversion of 55% being achieved after hours. | Journal of Chemistry, Vol. 47 (4), P. 491 - 498, 2009 SYNTHESIS OF POLYMER BRUSHES FROM SALEN LIGAND/SILICA AND ITS APPLICATION AS CATALYST FOR THE HYDROLYTIC KINETIC RESOLUTION OF EPICHLOROHYDRIN Received 8 January 2008 Nam T. S. Phan1, Christopher W. Jones2 1 Ho Chi Minh City University of Technology, Viet Nam 2 Georgia Institute of Technology, Atlanta, USA ABSTRACT A new approach to polymer brushes based on the surface-initiated atom transfer radical polymerization (ATRP) of functionalized salen monomer and styrene on nonporous silica was demonstrated. The hybrid material was characterized using FT-IR, TGA, DSC, 29Si and 13C CPMAS NMR techniques. The corresponding cobalt complex of the polymer brusches was used as a highly efficient recyclable catalyst for the hydrolytic kinetic resolution of racemic mixture of epichlorohydrin. The reaction was carried out under solvent-free condition at room temperature in the presence of mol% of cobalt, with enantiomeric excess (ee) of higher than 99% and a conversion of 55% being achieved after hours. While formally heterogeneous, the hybrid cobalt(salen) catalyst could offer the high enantioselectivity and activity of homogeneous catalysts due to the soluble polymer chains, and the advantages of facile separation and recyling of heterogeneous catalysts. I - INTRODUCTION Grafting polymers onto solid surfaces to form a so-called “polymer brushes” has become progressively intriguing in numerous commercially important technologies, such as biotechnology and advanced micro-electronics [1]. The hybrid materials possess the combination of both the properties of the inorganic solids such as robustness, and those of the polymers, in particular solubility and chemical activity. Recently, surface-initiated atom transfer radical polymerization (ATRP) technique has been extensively employed to synthesize several polymer brushes from flat substrates, porous glass filters, carbon nanotubes, and nanoparticles including .
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