Study On Hydrolysis Of Methyl Propionate Via Catalytic Distillation

Propionic acid is widely applied to feed,food,pesticide,pharmaceutical and other industries as an important fine chemical and raw material for organic synthesis.In industry,propionic acid is mainly prepared by oxidation of light hydrocarbon,of which there are some disadvantages,such as complex product,which is difficult to separate.To avoid the disadvantages above,the process of methyl propionate hydrolysis via catalytic distillation,which can produce highly purified propionic acid under mild conditions in a simple way,shows research significance.In this paper,the process of methyl propionate hydrolysis was experimentally studied in a batch stirred tank reactor after NKC-9 catalyst was screened.The factors of speed,catalyst partical size,reaction temperature,the amount of catalyst and the ratio of reactants were determined.The experiment data were fitted for the hydrolysis dynamics equation:(?)Based on the dynamics research,simulation was studied by Aspen plus,and effect of theoretical stages,feed stages,reflux ratio and the molar ratio of water to ester on the catalytic distillation process were examined respectively.A set of continuous catalytic distillation lab test tower made of stainless steel was built,and it is connected by several tower segments.The catalyst packing mode was designed,and the rectifying section and stripping section were full of 3×3 mm 316L stainless steel helices.The results showed that the appropriate feed stage for water is top of the reactive section,for methyl propionate is bottom of the reactive section,reflux ratio is 2 and molar ratio of reactants is 1.3:1.Under the conditions above,the conversion of methyl propionate reaches to 92.58%,meanwhile the mass fraction of propionic acid and water in bottom are 90.74%and 8.51%,and the mass fraction of methyl alcohol and methyl propionate in top are 84.64%and 15.21%,which is away from azeotropic composition and easy to separate.Experiment results and computer simulation results are in good agreement,and it provides basic data for the further research.