Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity...Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.展开更多
采用尿素和N,N-二甲基-1,3-丙二胺在常压下加热反应合成了1,3-双[3-(二甲胺基)丙基]脲(DPU),考察了反应温度、反应时间对DPU产率和粘度的影响,将不同条件下合成的DPU与二氯乙醚反应生成二氨基脲聚合物(PUB),并与PUB对照品进行比较。研...采用尿素和N,N-二甲基-1,3-丙二胺在常压下加热反应合成了1,3-双[3-(二甲胺基)丙基]脲(DPU),考察了反应温度、反应时间对DPU产率和粘度的影响,将不同条件下合成的DPU与二氯乙醚反应生成二氨基脲聚合物(PUB),并与PUB对照品进行比较。研究表明,在反应温度140℃,反应时间6 h条件下合成的DPU产率为91.8%,粘度290 c P。此条件下合成的DPU与二氯乙醚反应生成的PUB的色泽和粘度与对照品最接近。展开更多
The calcined Mg-A1 layered double hydroxides （LDHs） with a Mg/A1 molar ratio of 3 ： 1 were synthesized and characterized thoroughly by X-ray diffraction （XRD）, temperature-programmed desorption （TPD） of CO2, an...The calcined Mg-A1 layered double hydroxides （LDHs） with a Mg/A1 molar ratio of 3 ： 1 were synthesized and characterized thoroughly by X-ray diffraction （XRD）, temperature-programmed desorption （TPD） of CO2, and thermogravimetric analysis （TGA）. Thus the calcined Mg-A1 LDHs were used as catalyst for the catalytic synthesis of disubstituted ureas from amines and CO2. The effects of reaction time, reaction temperature, pressure, solvent and calcined temperature on activity have been investigated. The results indicated that aliphatic amines, cyclo- hexylamine and benzylamine can be converted to the corresponding ureas selectively over the calcined Mg-A1 LDHs catalysts with N-methyl-2-pyrrolidone （NMP） as solvent without using any dehydrating regent. The catalyst can be recycled several times with only slight loss of activity.展开更多
文摘Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.
文摘采用尿素和N,N-二甲基-1,3-丙二胺在常压下加热反应合成了1,3-双[3-(二甲胺基)丙基]脲(DPU),考察了反应温度、反应时间对DPU产率和粘度的影响,将不同条件下合成的DPU与二氯乙醚反应生成二氨基脲聚合物(PUB),并与PUB对照品进行比较。研究表明,在反应温度140℃,反应时间6 h条件下合成的DPU产率为91.8%,粘度290 c P。此条件下合成的DPU与二氯乙醚反应生成的PUB的色泽和粘度与对照品最接近。
基金The authors are grateful for the support from the Na-tional Natural Science Foundation of China （No. 21073058）, the Research Fund for the Doctoral Program of Higher Education of China （20100074110014）, and the Fundamental Research Funds for the Central Uni-versities.
文摘The calcined Mg-A1 layered double hydroxides （LDHs） with a Mg/A1 molar ratio of 3 ： 1 were synthesized and characterized thoroughly by X-ray diffraction （XRD）, temperature-programmed desorption （TPD） of CO2, and thermogravimetric analysis （TGA）. Thus the calcined Mg-A1 LDHs were used as catalyst for the catalytic synthesis of disubstituted ureas from amines and CO2. The effects of reaction time, reaction temperature, pressure, solvent and calcined temperature on activity have been investigated. The results indicated that aliphatic amines, cyclo- hexylamine and benzylamine can be converted to the corresponding ureas selectively over the calcined Mg-A1 LDHs catalysts with N-methyl-2-pyrrolidone （NMP） as solvent without using any dehydrating regent. The catalyst can be recycled several times with only slight loss of activity.
