4-氨基邻苯二甲酰亚胺合成的新工艺

New process for 4-aminophthalimide synthesis

以苯酐和尿素为原料，经过脱水环化、混酸硝化、Fe粉还原制备4-氨基邻苯二甲酰亚胺．在脱水环化反应中，加入催化剂以及甲苯作为脱水剂，回流蒸出生成的水分，缩短了反应时间，收率达到98．0％；在硝化反应中，加入P2O5作为吸水剂，使浓H2SO4。的用量减少一半，收率高于80．0％；在还原反应中，加入NH4Cl作为电解质，滴加浓HCl，调节pH至4—5，使Fe粉活化更充分，收率达到91．1％．目标产物用差示描扫（DSC）和红外光谱进行表征．实验结果表明：产物的熔点为293．3℃，为目标产物．

Phthalic anhydride and urea were used as raw materials for the synthesis of 4-aminophthalimide via dehydration-cyclization, nitration by mixed acid and reduction by iron powder. In dehydration-cyclization reaction, catalyst and toluene as dehydrater were added, and water was steamed out by reflux, thus the reaction time was reduced. The yield was 98. 0 %. Meanwhile, phosphoric anhydride was used as water absorbent in nitration, so the needed amount of concentrated sulfuric acid decreased in a half, the yield was more than 80. 0 %. Finally, the ammonium chloride was added as electrolyte and pH value was adjusted to 4-5 by dropping concentrated chlorhydric acid in reduction, so iron powder was activated adequately, and the yield was 91.1%. The target compound was characterized by differential scanning calorimetry （DSC） and Fourier transform infrared spectrometry（FT-IR）. Experimental results indicat that the melting point of the product is 293.3℃.