Synthesis of 2-Chloro-3-aminopyridine by Hydrogenation over Pd-Fe/TiO_2 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.