Abstract: The synthesis of N,N'-diphenylurea (DPU) from urea and aniline under atmospheric pressure without any catalyst and additional solvent was studied. The effects of reaction conditions and process intensification techniques on the yields of product DPU were investigated. Combining use of nitrogen gas flowing during reaction and vacuum evaporating after reaction, the yield of DPU reached 99.1% under optimum reaction conditions (reaction temperature 180℃, molar ratio of aniline/urea 5 and reaction time 1.5 h). The unreacted aniline could be recycled and reused. In addition, the reaction mechanism was also studied by means of HPLC analysis and proving experiment, it is ascertained that phenylurea is the major intermediate in the reaction.

Key words: N, N'-diphenylurea, urea, cleaner process, process intensification

摘要： 采用尿素和苯胺在常压下加热反应合成了N,N'-二苯基脲(DPU)，考察了不同工艺条件及反应、分离强化手段对DPU产率的影响，初步研究了反应机理. 实验结果表明，在反应过程中通入氮气，苯胺与尿素摩尔比为5，180℃反应1.5 h，反应后减压蒸发分离，DPU的单程产率(以尿素计)达到99.1%. 苯胺既是反应物，又是反应介质，反应后未反应的苯胺可循环利用. 该工艺不需加任何催化剂和其他溶剂. 对反应机理的初步研究表明，苯基脲为主要的反应中间体.

关键词: N, N'-二苯基脲, 尿素, 清洁工艺, 过程强化