有 3:1 的 Mg/Al 臼齿的比率的锻烧的 Mg-Al 分层的双氢氧化物(LDH ) 被 X 光检查彻底地综合并且描绘衍射(XRD ) , CO2 的规划温度的解吸附作用(TPD ) ,和 thermogravimetric 分析(TGA ) 。因此,锻烧的 Mg-Al LDH 从胺和 CO2 为 disubstituted 脲的催化合成被用作催化剂。在活动的反应时间,反应温度,压力,溶剂和锻烧的温度的效果被调查了。当,结果显示脂肪族的胺, cyclohexylamine 和 benzylamine 能与 N-methyl-2-pyrrolidone (NMP ) 在锻烧的 Mg-Al LDH 催化剂上有选择地被变换成相应的脲没有使用任何使脱水的总督的溶剂。催化剂能与活动的仅仅细微的损失若干次被再循环。
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.