Abstract:

Cu-doped Mg-Al layered double oxides were obtained through calcination at 400 ℃ from the corresponding Cu-doped Mg-Al hydrotalcite，which was prepared by wetness impregnation. The structural information of Cu/LDO catalysts was characterized by XRD，SEM，TG and nitrogen-adsorption/desorption techniques. Their catalytic activities were studied in the synthesis of propylene carbonate from urea and 1,2-propylene glycol. The influences of Cu doping amount，mole ratio of Mg-Al and different supports were investigated. The regeneration performance of catalysts was also studied. The results indicate that the combination of 1% Cu loading，3∶1 Mg∶Al mole ratio，Cu/Mg-Al LDO（3）gives much higher activity in propylene carbonate synthesis. Under the reaction condition of 1% Cu/ Mg-Al LDO（3），n(1,2-propylene glycol)∶n(urea)= 4∶1，reaction temperature of 170 ℃ and reaction time of 3 h，the yield of propylene carbonate reaches 96.1%. In a set of reuse experiments，there is almost no reduction on the catalytic activity.