| A series of Mg-Al type hydrotalcites were prepared by co-precipitation method and characterized by means of XRD, thermal analysis, SEM-EDX and CO2-TPD. The reaction between ethanol and propylene oxide has been carried out in a high pressure fixed bed reactor in the presence of calcined hydrotalcites as solid-base catalysts. The effect of aging method, aging time, calcination temperature as well as the chemical composition on the catalytic performance of the Mg-Al mixed oxides has been studied. The relationship between the activity and the basicity of the catalysts was studied.The results showed that the home-made catalysts all have the hydrotalcite typic structure. The Mg-Al mixed oxide derived from the hydrotalcites with an Mg/Al molar ratio of 3, which was aged for 12h and calcined at 550℃, exhibited excellent activity for the synthesis of propylene glycol monoethyl ether. The ultrasonic aging method might enhance the basicity of the calcined hydrotalcites, but it has different effect on the activity for the catalysts with different Mg/Al molar ratio. The strength and quantity of basic centers were enhanced with the increased of calcination temperature from 350℃to 550℃, and the activity of catalyst was also observably improved, but the further raising of calcination temperature caused the decrease of basic strength on surface, and thus the catalytic activity also decreased..Orthogonal experiment was designed to optimize the reaction condition, the result showed that the optimal reaction condition was the reaction temperature of 150℃, reaction pressure of 1.0MPa, liquid hourly space velocity of 1.0h-1 and molar ratio of ethanol to propylene oxide of 3:1.
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