稀土固体超强酸SO_4^(2-)/SnO_2-Nd_2O_3催化合成棕榈酸甲酯

Synthesis of Methyl Palmitate Catalyzed by Rare Earth Solid Superacid SO_4^(2-)/SnO_2-Nd_2O_3

采用溶胶-凝胶法制备稀土固体超强酸催化剂SO42-/SnO2-Nd2O3,以工业棕榈酸和甲醇为原料催化合成棕榈酸甲酯。考察了氧化钕添加量、焙烧温度、硫酸浓度、醇酸质量比、催化剂用量和反应时间对酯化反应的影响。结果表明,当氧化钕添加量为5%,以2.0 mol/L硫酸浸渍后,于550℃下焙烧3 h制备的催化剂性能最好。正交实验结果表明,合成棕榈酸甲酯的优化条件为:醇酸质量比为15∶25,催化剂用量为棕榈酸质量的6.0%,反应时间5 h。在此条件下,酯化率为90.1%。

Methyl palmitate was synthesized from industrial palmitic acid and methanol using rare earth solid superacid catalyst SO42-/SnO2-Nd2O3 which was prepared by sol-gel method.Effects of mole fraction of Nd2O3 in SnO2-CeO2,calcination temperature of catalyst,concentration of sulphuric acid,mass ratio of methanol to industrial palmitic acid,catalyst dosage and reaction time on the esterification were investigated.The results showed that the activity of SO42-/SnO2-Nd2O3 was better under the following conditions： loading amount of Nd2O3（based on total mole of SnO2-Nd2O3） was 5%,the concentration of sulfuric acid solution 2.0 mol/L,and calcination temperature 550 ℃.Orthogonal test results showed that the optimal reaction conditions of synthesizing methyl palmitate using SO42-/SnO2-Nd2O3 were as follows： the mass ratio of methanol to palmitic acid was 15：25,the catalyst quantity 6.0% of the palmitic acid and reaction time 5 h.The esterification rate is 90.1%.