MgO/γ-Al_2O_3高效催化碳酸乙烯酯水解合成乙二醇

Efficient synthesis of ethylene glycol by MgO/γ-Al_2O_3 catalytic hydrolysis of ethylene carbonate

制备了MgO/γ-Al2O3固体碱催化剂,采用X射线衍射、CO2-TPD程序升温脱附等手段表征了催化剂的结构和碱性质。结果表明:MgO负载量(质量分数)对催化剂上MgO的分散程度和催化剂碱性质有着重要影响。负载MgO后,γ-Al2O3仍然保持了原有的结构。当MgO的负载量小于9%时,几乎检测不到MgO特征衍射峰。催化剂的碱量随MgO负载量的增加而逐步提高,当负载量为9%时其碱量达到最大。考察了MgO负载量、反应时间、反应温度对碳酸乙烯酯(EC)水解反应合成乙二醇(EG)的影响。随着MgO负载量的增加,EC转化率逐渐上升。工艺条件研究表明:140℃和3 h以及酯水比(摩尔比)1∶1为最佳催化反应条件。采用9%MgO/γ-Al2O3为催化剂,在最佳工艺条件下,EG收率高达95.6%。

MgO/γ-Al2O3 solid alkali catalyst was prepared and used for the catalytic synthesis of ethylene glycol （EG） by the hydrolysis of ethylene carbonate （EC）. X-ray diffraction and CO2-TPD techniques were applied to characterize the structure and alkali properties of the catalyst respectively. The results show that the loading amount （mass fraction） of MgO plays a crucial role on the degree of MgO dispersion and alkali properties of the catalyst. increase of the loading MgO-loading amount, amount of MgO, and reaches the maximum when the loading amount is 9%. The effects of reaction time and temperature on the hydrolysis of EC were investigated. With the increase of the loading amount of MgO, the conversion rate of EC increases reaction time of 3 h, and the molar ratio of EC to H20 1 ： 1, MgO/γ-Al2O3 catalyst. gradually. Under the optimal condition of 140℃, a high EG yield of 95.6% is obtained with 9%MgO/γ-Al2O3 catalyst.