Process Research Of Diethyl Carbonate In A Reactive Distillation Column

Diethyl carbonate (DEC) is an important chemical raw material and green organic solvent, which can be widely used in medicine, pesticides, gasoline additives, battery electrolyte industry. DEC is an important substance as environmental benign intermediate and raw material in chemical industry. Its synthesis attracts much attention worldwide. Process research of DEC produced by transesterification in a reactive distillation column was conducted in this paper. The major research contents are as follows:(1) Two basic ionic liquid 1-butyl-3-methylimidazolium imidazole ([Bmlm]lm) and 1-butyl-3-methylimidazolium hydroxide ([BmIm]OH) were synthesized by functional desgn, and its structures were characterized by FT-IR, 1H NMR and 13C NMR.(2) Diffident ionic liquids were catalyzed reaction of propylene carbonate and ethanol to compare their catalytic activity and stability. The transesterification kinetics of propylene carbonate and ethanol catalyzed by [BmIm]Im was measured in a continuous stired-tank reactor. The effects of catalyst amount, reaction temperature and reactant molar ratio on reaction rate were investigated, and according to the transesterification mechanism, a homogeneous kinetics model was established by the least squares method.(3) The experiments of continuous synthesis of DEC catalyzed by Sodium ethoxide were carried out in a reactive distillation column. The effects of operation factors, e.g. evaporation capacity, space velocity, catalyst amount and reactant molar ratio, on propylene carbonate conversion were investigated. The applicable operating condition was obtained after reactive distillation experiments.(4) Based on the above research, equilibrium stage model was established to simulate the distillation process of product separation. Aspen Plus software was used to calculate the appropriate parameters of distillation separation process. The influence of the number of theoretical plates, feed stage, reflux ratio, operating pressure were investigated and the appropriate separation process parameters were obtained.