非晶态Ni-B合金在催化苯丙酮酸胺化加氢反应中活性寿命的研究

Recycling performance of amorphous Ni-B alloy catalyst for hydrogenation of phenylpyruvic acid to phenylalanine

通过化学还原法制备了非晶态Ni-B合金催化剂,考察了催化剂在苯丙酮酸胺化加氢制备苯丙氨酸反应中的活性寿命。结果表明,非晶态Ni-B合金催化剂表现出比传统催化剂如雷尼镍和漆原镍等更为优异的活性与寿命。Ni-B合金催化剂经过简单的过滤回收步骤,重复使用5次后,催化活性没有明显大幅度下降,而雷尼镍和漆原镍分别循环使用3次和2次后,催化活性显著降低。结合XRD、DSC和TEM等手段,针对新鲜和使用回收后的催化剂进行了表征,发现非晶态结构在苯丙酮酸加氢反应环境中没有出现明显晶化现象,而小尺寸纳米颗粒的团聚和部分镍的氧化可能是导致催化剂活性降低的主要原因。

Amorphous Ni-B ahoy catalyst was prepared by chemical reduction method and its recycling performance in the hydrogenation of phenylpyruvic acid（PPA） to phenylalanine（Phe） was investigated. The results showed that amorphous Ni-B alloy catalyst exhibited better life-span and activity compared with traditional nickel catalysts. Amorphous Ni-B alloy recycled by simple filtration could be reused five times without obvious decrease of catalytic activity, while the activity of Raney Ni and Urushibara nickel decreased sharply after being reused three and two times, respectively. The fresh and recycled catalysts were characterized by XRD, DSC and TEM. The results indicated that no significant crystallization of the amorphous structure was found in the hydrogenation, and the deactivation of amorphous catalyst was mainly ascribed to the aggregation of nanometer amorphous alloy and the oxidation of partial nickel.