| Au nanoparticles stabilized by polystyrene-co-polymethacrylic acid microspheres (PS-co-PMAA) were prepared and characterized via X-ray diffraction (XRD), and transmission electron microscope (TEM). The Au nanoparticles supported on the microspheres showed highly selective catalytic activity for homo-coupling reactions of arylboronic acids in a system of aryl-halides and arylboronic acids. X-ray photoelectron spectroscopy (XPS) spectra of the catalyst shows large amounts of Au(I) complexes band to the surface of the Au nanoparticles, which contributes to the selective homocoupling of the arylboronic acids. More importantly, this supported Au complex is a highly recyclable catalyst. The supported Au catalyst can be recycled and reused at least 6 times for a phenylboronic acid reactant, whereas the parent complex shows very low catalytic activity for this compound. The high catalytic activity of this material is attributed to: 1) the high surface to volume ratio which leads to more active sites being exposed to reactants; 2) the strong surface binding of the Au nanoparticle to the Au(I) complexes, which enhances both the stability and the catalytic activity of these complexes.In addition, condensation reaction between sterically hindered ketones and ethyl acetate was studied, which is a new method for the synthesis of ethyl 3,3'-diphenylacrylate and its derivatives. Lewis acid base pair-AlCl3/Et3N was found to be efficient for this kind of reaction. Under the optimized conditions, we carried out the condensation reaction with a series of substrates. The products of the reactions were characterized by 1HNMR and GC-MS. Compared with the reactions reported in literatures, the method in this paper was simple ,facile and efficient, also, the catalyst was inexpensive. This method is not only suitable for laboratory research but also suitable for large-scale industrial production, and it has been demonstrated potential industrial value.
|
PDF Full Text Request