Pd-Fe/TiO_2催化加氢合成2-氯-3-氨基吡啶的研究

2-氯-3-氨基吡啶是一种重要的医药和农药中间体。用Pd-Fe/TiO2催化2-氯-3-硝基吡啶常压下选择性加氢合成了2-氯-3-氨基吡啶,考察了Pd和Fe质量分数、催化剂用量、溶剂及其用量、反应温度和反应时间等对加氢反应的影响。结果表明,Pd-Fe/TiO2对2-氯-3-硝基吡啶的加氢反应有很高的催化活性和选择性,在2-氯-3-硝基吡啶0.05 mol,催化剂0.15 g,无水乙醇40 mL,氢气压力0.1 MPa,50℃反应2 h的条件下,2-氯-3-氨基吡啶的收率98.3%,选择性达到99.5%,无脱卤现象。催化剂经重复使用10次,催化活性和选择性仍无明显下降。

Synthesis of 2-Chloro-3-aminopyridine by Hydrogenation over Pd-Fe/TiO2 Catalyst

2-Chloro-3-aminopyridine is an important intermediate for pharmaceutical and pesticide.2-Chloro-3-aminopyridine was synthesized by selective hydrogenation of 2-chloro-3-nitrotopyridine over Pd-Fe/TiO_2 catalyst at normal pressure.The influences of mass fractlon of Pd and Fe catalyst dosage,solvent and its volume,reaction temperature and reaction time on the hydrogenation of 2-chloro-3-nitrotopyridine were investigated.The results showed that Pd-Fe/TiO_2 catalyst exhibited high catalytic activity and selectivity for the hydrogenation of 2-chloro-3-nitrotopyridine.Under the conditions of 2-chloro-3-nitrotopyridine 0.05 mol,catalyst(mass fraction of Pd and Fe is 5% and 0.2%) dosage 0.15 g,ethanol 40 mL,H_2 pressure 0.1 MPa,50(°C) and 2 h,the hydrogeantion of 2-chloro-3-nitrotopyridine to 2-chloro-3-aminopyridine reached 98.3% yield and 99.5% selectivity in the presence of Pd-Fe/TiO_2 catalyst,and no dehalogenation product was found.Pd-Fe/TiO_2 catalyst was reused at least 10 times without significant decrease in activity and selectivity.