摘要
To facilitate the recovery of Pb/SiO catalyst, magnetic Pb/Fe O /SiO samples were prepared separately by emulsification, sol-gel and incipient impregnation methods. The catalyst samples were characterized by means of X-ray diffraction and N adsorption-desorption, and their catalytic activity was investigated in the reaction for synthesizing propylene carbonate from urea and 1,2-propylene glycol. When the gelatin was applied in the preparation of Fe O at 60°C and the pH value was controlled at 4 in the preparation of Fe O /SiO , the Pb/Fe O /SiO sample shows good catalytic activity and magnetism. Under the reaction conditions of a reaction temperature of 180°C, reaction time of 2 h, catalyst percentage of 1.7 wt-% and a molar ratio of urea to PG of 1∶4, the yield of propylene carbonate attained was 87.7%.
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