二苯脲和甲醇合成苯氨基甲酸甲酯

以二苯脲和甲醇为原料、CO2为保护气,在催化剂作用下合成了苯氨基甲酸甲酯(MPC),考察了催化剂、反应温度、反应时间、原料配比对MPC合成反应的影响,确定了适宜的反应条件。实验结果表明,CO2的加入改进了原有MPC反应工艺。在催化剂的作用下,CO2和副产物苯胺发生反应生成二苯脲,一方面减少生成物苯胺的含量,另一方面生成的二苯脲可作为原料进一步与甲醇反应,从而提高了二苯脲的转化率、MPC的选择性和收率;在以PbO/Al2O3为催化剂、反应温度180℃、反应时间3h、甲醇与二苯脲的质量比为10的反应条件下,二苯脲的转化率为95.68%,MPC选择性为88.16%,MPC的收率为84.35%。

Synthesis of Methyl N-Phenyl Carbamate from Methanol and Diphenylurea

Methyl N-phenyl carbamate(MPC)was synthesized from methanol and diphenylurea in CO_2 atmosphere.Effects of catalysts,reaction temperature,reaction time and mass ratio of methanol to diphenylurea on synthesis of MPC were investigated.The continuous introducing of CO_2 can improve the synthesis.CO_2 reacts with byproduct aniline to produce diphenylurea on the catalyst,which facilitate the proceeding of main reaction and furthermore the newly produced diphenylurea itself reacts with methanol to produce additional MPC.Therefore PbO/Al_2O_3 showed higher catalytic activity and MPC selectivity than other catalysts.Under optimal reaction conditions: reaction temperature 180 ℃,reaction time 3 h and m(methanol) ∶m(diphenylurea)10,conversion of diphenylurea,selectivity to MPC and yield of MPC can reach 95.68%, 88.16% and 84.35%, respectively.