KF-MgO固体碱催化剂的表征及油脂醇解活性

Characterization and Alcoholysis Activity of KF-MgO Solid Base Catalyst

以二水合氟化钾、乙酸镁(四水)为原料,经过混合研磨、焙烧制得KF-MgO固体碱催化剂。采用单因素实验得到的优化制备条件为:摩尔比n(KF·2H_(2)O):n(MgAc_(2)·4H_(2)O)=1,焙烧温度500℃,焙烧时间3 h。将制得的固体碱催化剂催化蓖麻油与甲醇的酯交换反应,得生物柴油的折射率为1.4626,蓖麻油转化率为96.36%。通过热重分析、X射线衍射和扫描电镜对最佳条件下制备的KF-MgO固体碱催化剂及其前驱体进行表征,结果表明,KF-MgO固体碱催化剂的前驱体在500℃左右分解过程基本结束。催化剂主要以KMgF_(3)的形式存在,呈蜂窝状,有一定数量的孔洞。

KF-MgO solid base catalyst was prepared from the raw materials of potassium fluoride dihydrate and magnesium acetate(tetrahydrate)by mixing,grinding and roasting.The optimal preparation conditions for the single-factor experiment were:n(KF·2H_(2)O):n(MgAc_(2)·4H_(2)O)=1,roasting temperature of 500℃,and roasting time of 3 h.The solid alkali catalyst produced under the above conditions was used to catalyze the ester exchange reaction of castor oil and methanol,and the refractive index of biodiesel was 1.4626 and the conversion rate of castor oil was 96.36%.The KF-MgO solid alkali catalyst and its precursor prepared under optimal conditions were characterized by thermal weight analysis,scanning electroscope and X-ray diffraction,and the results indicated that,the decomposition process of the precursor of KF-MgO solid base catalyst was basically completed at about 500℃.The catalyst was mainly in the form of KMgF_(3),in the shape of honeycomb with a certain number of holes.