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

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%.