含铷固体超强碱Rb_2O/γ-Al_2O_3的制备及其催化酯交换反应研究  

Preparation of Rubidium Solid Superbases and Its Catalytic Application in Interesterification

作　　者：阳卫军[1] 秦明高 刘世明[1] 

机构地区：[1]湖南大学化学化工学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2015年第12期64-69,共6页Journal of Hunan University:Natural Sciences

基　　金：中央高校基本科研业务费专项基金资助项目(53110704012)

摘　　要：以从盐湖卤水中提取的RbCl为原料,利用原位法和浸渍法制备了含铷的固体超强碱Rb_2O/γ-Al_2O_3.以蔗糖为模板剂,以Rb_2CO_3及Al(NO_3)_3为反应物,原位法制备了Rb_2O/γ-Al_2O_3.同时以蔗糖为模板剂,先分别以Al(NO_3)_3和异丙醇铝(Al[CH(CH_3)_2]_3)为铝源制备了介孔γ-Al_2O_3,再通过浸渍RbNO_3溶液,制备了一系列的负载型Rb_2O/γ-Al_2O_3.通过优化制备条件,两种方法制备的Rb_2O/γ-Al_2O_3的碱强度均可达26.5以上,即为超强碱.把制备的超强碱Rb_2O/γ-Al_2O_3用于三醋酸甘油酯和甲醇为模型反应物模拟生物柴油制备过程中的催化酯交换反应.得到了最佳的催化反应条件:原料醇酯比8∶1,反应温度338K,反应时间4h,催化剂用量w三醋酸甘油酯=6.0%,在此工艺条件下乙酸甲酯产率达98%以上.Solid superbases Rb2 O/γ-Al2 O3 were prepared from rubidium salts separated from salt brine. Sucrose was used as the template, Rb2COa （prepared from RbCl） and AI（NOa）a as the raw materials, we prepared Rb2O/γ-Al2O3 successfully by using in-situ method. In impregnation method, we first used sucrose as the template, Al（NO3）3 and AI[-CH（CH3）2]3 as aluminum sources, respectively to prepare γ- Al2O3 ,and then a series of Rb2O/γ-Al2O3 with different rubidium contents through the impregnation of RbNO3 （prepared from RbCl）. The base strength of Rb2O/γ-Al2O3 both can reach 26.5 or more, belonging to superbase prepared through the two methods by controlling the conditions. The prepared Rb2O/γ-Al2O3 solid superbases were used to simulate interesterification in the process of producing biodiesel by catalyzing triglycerides acetate and methanol. The optimum reaction conditions were as follows： the ratio of alcohol to ester was 8 ： 1, the reaction temperature was 338 K, the reaction time was 4 h, and the aount of catalyst is 6.0 % of the weight of ester. Under those conditions, the productivity of methyl acetate was up to 98%.

关 键 词：铷 Γ-AL2O3 固体超强碱 酯交换反应 三醋酸甘油酯 

分 类 号：O643.36[理学—物理化学]