Catalytic Hydrogenation Of Aromatic Nitriles By Quaternary Amorphous Catalyst

Due to amorphous alloy's short-range ordering and long-range disordering structure, it has some excellent catalytic properties, such as the high catalytic activity, selectivity and catalytic efficiency, which attacts more and more researchers.A novel amorphous alloy containg Ni, Al, Fe and Cr was prepared by the rapidly quenched method and then leached by alkali. XRD analysis showed the catalyst was amorhous. The above catalyst was used for the catalytic hydrogenation of benzonitrile, isophthalonitrile and 1,4-dicyanobenzene, respectively. The effects of reaction parameters including solvent, initial concentration of the substrate, amount of the catalyst, reaction temperature and pressure were investigated in the above three substrates' reaction systems. Compared with those in literature, the quaternary amorphous catalyst showed higher selectivity and activity. The yield of the product was improved while the selectivity was also increased.The optimized reaction conditions were concluded based on the experiment results. Under the optimized reaction conditions (m catalyst/m substrate=6%, m NaOH/m substrate = 10%, the initial concentration of benzonitrile=2.0 mol/L, ethanol as solvent, 2.0 MPa and 40℃), the conversion of benzonitrile in 1 h was as high as 99.9% while the selectivity of benzylamine was up to 95.2%. In addition, under the optimized reaction conditions (m catalyst/ m isophthalonitrile =6.7% in methanol, initial concentration of substrate=1.5 mol/L, 1.5-2.0 MPa and 80℃), the conversion of isophthalonitrile in 150 min was as high as 99.9% and the yield of m-xylylenediamine reached 96.0%. Furthermore, under the optimized conditions (m catalyst/m substrate=6.7%, methanol as solvent, the initial concentration of substrate= 1.5 mol/L, 120 min, 2.0 MPa and 90℃), 1,4-dicyanobenzene was 100% converted and the yield of 1,4-benzenedimethanamine was as high as 97.6%.The life time of quaternary amorphous catalyst was tested using isophthalonitrile as substrate. Results showed that the catalytic activity was almost constant after 26 runs of reaction by adding a little amount of fresh catalyst. The yield of m-xylylenediamine basically reached 98%, illustrating its potential application in industry.