CaO/ZnO固体碱催化制备生物柴油及催化剂的表征

Synthesis of Biodiesel Catalyzed by Solid Base CaO/ZnO and Characterization of CaO/ZnO

用浸渍法制备了Ca(Ac)2/ZnO,再将其通过高温焙烧制得CaO/ZnO。用正交实验法考察了浸渍液的质量分数、焙烧温度及焙烧时间对CaO/ZnO催化活性的影响。以优化条件制备的CaO/ZnO为催化剂,考察了蓖麻油与甲醇的催化酯交换反应。采用TG-DTG、XRD、BET表征了优化条件下制得的Ca(Ac)2/ZnO和CaO/ZnO。结果表明,适宜的CaO/ZnO催化剂制备条件为浸渍液质量分数0.20、焙烧温度973K、焙烧时间3h。当醇/油摩尔比9、催化剂/油质量比0.03、反应温度338K、反应时间4.5h时,蓖麻油转化率可达99.7%。Ca(Ac)2/ZnO的TG-DTG曲线在690K和1020K有2个明显的失重峰;CaO/ZnO和ZnO具有相同的晶相结构,表明CaO在ZnO表面呈高度分散状态;CaO/ZnO比表面积为6.10m2/g,平均孔半径为2.59nm。

Ca（Ac）2/ZnO was prepared by impregnation and with which CaO/ZnO was made by high temperature calcination. Effects of impregnating solution mass fraction, calcination temperature and calcination time on the catalytic activity of CaO/ZnO were investigated through orthogonal experiments. The transesterification of castor oil with methanol was studied by using CaO/ZnO as a catalyst, prepared under the optimal conditions. Ca（Ac）2/ZnO and CaO/ZnO prepared at optimal conditions were characterized by TG-DTG, XRD, BET. The results showed that the suitable preparation conditions of CaO/ZnO was impregnating solution mass fraction 0. 2, calcination temperature 973 K and calcination time 3 h. Under the conditions of alcohol/oil molar ratio 9, catalyst/oil mass ratio 0.03, reaction temperature 338 K and reaction time 4.5 h, castor oil conversion could reach 99.7%. There were two distinct weightless peaks at 690 K and 1020 K in TG-DTG curves of Ca （Ac）2/ZnO. CaO/ZnO and ZnO had the same crystalline structure, displaying CaO being utterly dispersed on ZnO. The surface area of CaO/ZnO was 6.10 m2/g and its average pore radius was 2.59 nm.