Study On The Synthesis Of N-phenyl Maleimide

The preparation of N-phenyl maleimide(N-PMI) is studied in this paper. Using anilineand maleic anhydride as raw materials, N-phenyl maleic acid is synthesized through theadditional reaction, then the target product N-phenyl maleimide is produced through cyclicdehydration.The optimum conditions of the additional reaction are determined. N-PMA issynthesized with aniline(ANL) and maleic anhydride(MAN) as raw materials whose molarratio(n_ANL/n_MAN)is 1.1, the yield of N-PMA is 93.15% in acetone method;the yield ofN-PMA is 97.83% in xylene method. The research is focused on the cyclic dehydrationreaction. The yield of N-PMI is 84.91% in acetic anhydride method;the yield of N-PMI is75.43% in atmospheric azeotropic method;the yield of N-PMI is 85.78% in decompressedazeotropic method, in which the advantages of acetic anhydride method and atmosphericazeotropic method are combined. On the basis of the above methods, a high performancenew supported catalyst is designed and prepared, and a new technology of supportedcatalytic azeotropic method is developed. In supported catalytic azeotropic method,N-phenyl maleimide is synthesized in xylene solvent under atmospheric pressure, withN-PMA as the raw material. The supported catalyst can be used repeatedly for more than30 times with the average yield of N-PMI 89.32%, and the purity of 99.42%.