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キーワード:
N-functionalized hollow vapour-grown carbon nanofiber; cascade synthesis; immobilized lipase;
要旨:
The synthesis of (R)-1-phenylethyl acetate starting from acetophenone was investigated in this work. The first step consisted in the selective catalytic hydrogenation of acetophenone to form racemic 1-phenylethanol over a heterogeneous metal catalyst, Pd supported on N-functionalized vapour-grown carbon nanofibers (N-VGCFs), at 70 oC under atmospheric hydrogen pressure in toluene. The acylation of the formed racemic 1-phenylethanol was subsequently performed over an immobilized lipase in the same reaction pot. The main parameters investigated in this work were the role of the basic N-VGCF supports as well as the reduction procedure of the supported Pd catalysts (Pd-N-VGCF). The basic N-VGCF supports were synthesized by post-treating oxidized VGCFs in gaseous NH3 at high temperature (ammonolysis) prior to Pd addition by sol immobilization. The catalysts were characterized by nitrogen adsorption, hydrogen temperature programmed desorption, adsorption microcalorimetry and by SEM and TEM. The results revealed that the catalytic activity of the Pd-N-VGCF catalysts was highly dependent on the reduction procedure. The highest desired product yield, 35 %, was obtained over a Pd-N-VGCF catalyst when the support was treated at 400oC with gaseous ammonia prior to Pd addition.
