Study on Pd-catalyst used for hydrogenation of fluorine-containing aromatic nitro-compounds

The present situation of synthesis of aramides by catalytic hydrogenation was reviewed.The preparation of Pd-Fe/SiO2 catalyst by the dipping process is introduced.Factors affecting catalytic properties,such as carrier,components,reductant,baking temperature,and time,were studied,and optimal conditions were obtained as:w(Pd)=5%,w(Fe)=0.2%;potassium borohydride as reductant;Pd-Fe/SiO2 was roasted for 4 h at 500 ℃.Tests for reusing the catalyst,verifying optimal conditions,and comparing with other catalysts such as Raney Ni,Pt/C,and Pd/C were made.The results showed that Pd-Fe/SiO2 catalyst had high selectivity,the yield of the reaction was more than 97.5%,the purity of product was more than 98.0%,and the catalyst can be reused 10 times .