The New Method For N-phenyl Maleimide Synthesis

N-phenyl maleimide is abbreviated NPMI or N-PMI, pale-yellowaciform crystals, and the melting point is90℃. It is a kind of heat resistingorganic monomer. N-PMI is mainly used as heat resisting modifier agent ofPVC、PMMA、 ABS. In this paper, the writer studied of N-PMI andsummarizes application. The writer described the research progress as well asits advantages and disadvantages of different synthesis at home and abroadsystematically.The preparation of N-phenyl maleimide by acetic anhydride method,atomospheric azeotropic method and decompressed azeotropic method isstudied in this paper. The yield of N-PMI is60~85%in acetic anhydridemethod. The yield of N-PMI is60~85%that N-PMI is synthesized in toluenesolvent under atomospheric pressure, with phosphoric acid andp-toluenesulfonic acid as catalyst. The yield of N-PMI is60~85%indecompressed azeotropic method, in which the advantages of acetic anhydridemethod and atomospheric azeotropic method are combined. But it needdecompression conditions, so this method is not suitable for industrialproduction.The optimum conditions of a variety of reactions are determined in thepaper. On the basis of above method, a new technology of acidic ionic liquid azeotropic method is developed. In acidic ionic liquid azeotropic method, asthe target product N-PMI is synthesized in toluene solvent underatomospheric pressure, with N-phenyl maleimide amide acid as raw materials,acidic ionic liquid as catalyst. The catalyst (acidic ionic liquid) can be usedrepeatedly for more than20times. The average yield of N-PMI arrives at87.12%, and the purity of N-PMI arrives at99%. The target product ischaracterized by FTIR、HPLC、1HNMR and GC etc.