Abstract:

Mg-Al mixed metal oxide modified by NaAlO₂ was prepared at a certain temperature with Mg-Al hydrotalcite that synthesized by constant pH co-precipitation method as precursor and sodium aluminate as the active component.The charac-terization of XRD,SEM,BET,CO₂-TPD and DSC-TG for the catalysts was carried out.It was found that the sodium aluminate prepared at high temperature was dispersed on the metal oxides stably.The catalyst can catalyze the transesterification of ethylene carbonate and methanol to synthesize dimethyl carbonate（DMC） and ethylene glycol（EG） under mild reaction con-ditions,showing high catalytic activity and high selectivity to the product.Under the conditions as follows：the amount-of-substance ratio of methanol to EC was 10∶1,4 h and 65 ℃,then the DMC yield was 74.8%,and the selectivity on DMC and EG both reached 100%.During the cycling experiment,the catalyst showed good stability and no obviously decrease of catalytic activity was observed after reused for five times.The preparation method of the catalyst is simple and cheap.The catalyst is easy to separated from the product and could be reused.It is an efficient transesterification catalyst for synthesis of dimethyl carbonate and glycol,which showing prospective in industrial applications.

Key words: hydrotalcite, magnesium-aluminum mixed metal oxide, sodium aluminate, dimethyl carbonate, ethylene glycol