Ca-Mg-Zn-Al-O固体碱催化剂的制备及其催化性能

Preparation of Ca-Mg-Zn-Al-O Solid Base Catalyst and Its Activity

采用共沉淀和高温焙烧的方法制备了Ca-Mg-Zn-Al-O固体碱催化剂,并采用正交实验对催化剂的制备条件进行了优化;通过TG-DTA,BET,XRD,SEM等手段及Hammett指示剂法对催化剂及其前体进行了表征。实验结果表明,正交实验得到的较适宜的制备条件为：陈化温度80℃、陈化时间12 h、焙烧温度700℃、焙烧时间5 h。以在上述优化条件下制备的Ca-Mg-Zn-Al-O固体碱为催化剂,用于蓖麻油与甲醇的酯交换反应,在n（甲醇）∶n（蓖麻油）=9、m（催化剂）∶m（蓖麻油）=0.04、搅拌转速550 r/min、反应温度65℃、反应时间3 h的条件下,蓖麻油的转化率稳定在95%~99%之间。

Ca-Mg-Zn-Al-O solid base catalyst was prepared by coprecipitation and calcination. The catalyst and its precursor were characterized by means of TG-DTA,BET,XRD,SEM and Hammett indicator method. The relationship between the structure and surface properties of the catalyst was investigated. The suitable preparation conditions for the catalyst were obtained by orthogonal experiments as follows：aging temperature of 80 ℃,aging time of 12 h,calcination temperature of 700 ℃ and calcination time of 5 h. The catalyst was used in the transesterification of castor oil and methanol,and under the optimal conditions of 65 ℃,3 h,n（methanol）∶n（castor oil） 9,m（catalyst）∶m（castor oil） 0.04 and stirring speed 550 r/min,the castor oil conversion was in the range of 95%-99% steadily.