Ce-Ca-Zn-Al-O固体碱催化剂的制备研究  

Preparation of Ce-Ca-Zn-Al-O solid base catalyst

作　　者：靳福全[1] 

机构地区：[1]太原工业学院化学与化工系,山西太原030008

出　　处：《现代化工》2016年第6期78-82,共5页Modern Chemical Industry

基　　金：山西省高校科技开发项目(2010130);山西省高等学校大学生创新创业训练项目(2015449)

摘　　要：以铈、钙、锌、铝的硝酸盐为原料,尿素为沉淀剂,经沉淀、焙烧制得Ce-Ca-Zn-Al-O固体碱催化剂。通过单因素试验考察了催化剂制备条件对催化剂活性的影响,得到制备催化剂的优化工艺为:n(Ce)∶n(Ca)∶n(Zn)∶n(Al)=0.1∶2∶4∶2,反应温度为125℃,焙烧温度为750℃,焙烧时间为6 h。将优化条件下制备的催化剂用于蓖麻油和甲醇的酯交换反应,在醇/油摩尔比为9,催化剂/油质量比为0.04,反应温度为60℃,搅拌速率为550 r/min及反应时间为4 h的条件下,蓖麻油转化率可达86%。采用Hammett指示剂法、TG、BET、XRD及SEM对催化剂及其前驱体进行表征,结果表明:Ce-Ca-Zn-Al-O固体碱的碱强度H_在7.2~11.2之间;Ce-Ca-Zn-Al类水滑石在760℃后质量几乎为定值;Ce-Ca-Zn-Al-O固体碱催化剂比表面积为28.51 m^2/g,孔容为0.061 38 cm^3/g,且主要由Ca O、Zn O及Al2O33种晶体组成。A Ce-Ca-Zn-Al-O solid base catalyst is prepared by precipitation and roasting process,using cerium,calcium,zinc,aluminum nitrate as raw material,urea as precipitating agent. The influence of the catalyst preparation conditions on the activity of the catalyst is investigated by single factor test. The optimal preparation conditions are shown as follows： 0. 1∶ 2∶ 4 ∶ 2 of n（ Ce） ∶ n（ Ca） ∶ n（ Zn） ∶ n（ Al）,125℃ of the reaction temperature,750℃ of the calcination temperature and 6 h of the calcination time. The catalyst prepared under optimal conditions is used to catalyse the ester exchange reaction of castor oil and methanol. The conversion rate of castor oil can reach 86% under the following conditions： 9 of the molar ratio of alcohol and oil,0. 04 of the mass ratio of catalyst and oil,60℃ of the reaction temperature,550 r / min of stirring speed and 4 h of reaction time. The catalyst and its precursor are characterized by Hammett indicator method,TG,BET,XRD and SEM. The results show that the base strength of Ce-Ca-Zn-Al-O solid base（ H） is between 7. 2- 11. 2. The mass of Ce-Ca-Zn-Al hydrotalcite-like solid base is almost constant after 760℃.The specific surface area and pore volume of the Ce-Ca-Zn-Al-O solid base catalyst is 28. 51 m^2/ g and 0. 061 38 cm^3/ g,respectively. This Ce-Ca-Zn-Al-O solid base catalyst is mainly composed of Ca O,Zn O and Al2O3 crystals.

关 键 词：复合氧化物 固体碱 催化剂 油脂 生物柴油 

分 类 号：O614[理学—无机化学] TK6[理学—化学]