Preparation Of M-xylylenediamine By The Hydrogention Of Isophthalonitrile

M-xylylenediamine is an aromatic amine compound widely used in Chemical industry.As an excellent epoxy resin curing agent,m-xylylenediamine is widely applied in national defense and aerospace.m-xylylenediamine is also an important fine chemical intermediates to synthesis polyurethane,xylene nylon resin,aromatic polyamide and isocyanate.m-xylylenediamine mainly rely on import and will demand more with the development of defense science,aerospace and the auto industry.At present,m-xylylenediamine is mainly synthesized by hydrogenation of isophthalonitrile over Raney Ni catalyst in industry.However,Raney Ni is easy to be inactivatied due to mechanical damage during hydrogenation.In this paper,the catalytic properties of some commercial Raney Ni catalysts and the reason of inactivation were discussed.The results showed that the activity of Raney Ni and the selectivity of m-xylylenediamine were related with the partical size and structure of catalyst.The mixture solvent of methanol and toluene was favorable to dissolve isophthalonitrile.The characterization results by XRD indicated that mechanical damage of Raney Ni was the main factor to the inactivation of Raney Ni.The catalytic properties of supported Pd,Ru catalysts were also discussed in this paper.The results showed that the activity of Pd/C was increased with increasing palladium content,however,the selectivity of m-xylylenediamine was reduced.The addition of proper inhibitor could improve the selectivity of m-xylylenediamine.Ru-Ni?Ru-Co?Ni-Co bimetallic catalysts supported on treated silica were prepared by conventional impregnation.Active evaluation results show that The catalytic properties of Ru-Ni/SiO2 is as good as Raney Ni and better selectivity of m-xylylenediamine than Raney Ni.The 95.18%yield has been reached without any inhibitors under the conditions of 140 ?,4 MPa with mixture solvent of methanol and toluene over 5%Ru-5%Ni/SiO2.The characterization results by XRD and H2-TPR indicated that the addition of Ru reduced the reduction temperature and improved the dispersion of Ni.Therefore,supported Ru-Ni bimetallic catalysts display better application prospect than Raney Ni...