尿素法合成甲苯-2,4-二氨基甲酸正丙酯反应

以2,4-二氨基甲苯（TDA）、尿素和正丙醇（PrOH）为原料，非催化合成了甲苯-2,4-二氨基甲酸正丙酯（TDC-P），考察了反应条件对该合成反应的影响，并基于反应产物的液相色谱 质谱分析结果，推测了可能的反应路径。结果表明，该反应适宜的反应条件为n(TDA)/n(Urea)＝1/3、n(TDA)/n(PrOH)＝1/84、反应温度170℃、反应压力0.6 MPa、反应时间4 h。此时，TDA转化率95.3%，TDC-P产率66.1%、选择性69.4%。合成TDC-P可能的反应路径有3条，（1）经过氨基甲酸正丙酯和3-氨基-4-甲基苯氨基甲酸正丙酯或2-甲基-5-氨基苯氨基甲酸正丙酯生成TDC-P的反应路径；（2）以2,4-甲苯二脲为中间产物的反应路径；（3）以3-脲基-4-甲基苯氨基甲酸正丙酯或2-甲基-5-脲基苯氨基甲酸正丙酯为中间产物的反应路径。

Synthesis of Dipropyl Toluene-2,4-dicarbamate via Urea Route

Dipropyl toluene-2,4-dicarbamate (TDC-P) was synthesized successfully by using 2,4-diamino toluene (TDA), urea and propanol (PrOH) as raw materials in the absence of catalyst. The effects of reaction conditions on the synthesis of TDC-P were studied. The plausible reaction paths existed in this synthesis were speculated based on the result of HPLC-MS analyses. The results showed that the suitable reaction conditions for this synthesis were TDA/urea molar ratio of 1/3, TDA/PrOH molar ratio of 1/84, reaction temperature of 170℃, reaction pressure of 0.6 MPa and reaction time of 4 h, under which TDA conversion, TDC-P yield and selectivity were 95.3%, 66.1% and 69.4%, respectively. There existed three possible reaction paths in the TDC-P synthesis, which were (1) through propyl carbamate and propyl 2-methyl-5-amino-N-phenylcarbamate or propyl 3-amino-4-methyl-N-phenylcarbamate, (2) via toluene-2,4-bisurea as an intermediate, (3) via propyl 3-ureido-4-methyl-N-phenylcarbamate or propyl 2-methyl-5-ureido-N-phenylcarbamate as an intermediate. .