Study On The Separation Technology For Ethyl Acetate-Methanol Solvent

Methanol and ethyl acetate are widely used in drug production fields as solvent.The massive methanol-ethyl acetate mixed solvent is produced in the gastrodineproduction process of a medicine enterprise in Chongqing. Methanol and ethyl can’t beeffectively separated from the mixed solvent, which promote the production cost of theenterprise and restrict the development of gastrodine production. This paper aims to putforward economic, environmental and effective separation recycling schemes, realizingmethanol and acetic ester cycle use.The methanol-ethyl acetate mixed solvent is easy to form the binary azeotrope, andwhich contains a small amount of gastrodine. This paper presents that, first to distill themixed solvent, for recycling residual gastrodin, than to use the method of salt effect andextractive distillation, for recovering the ethyl acetate and methanol. A large number ofethyl acetate is separated and refined in the salt effect stage. The salt selection, theinfluence factors of separation process, the salt for the ethyl acetate purified and heinfluence factors of refining process were studied by theoretical analysis and experiment.Eventually making sure to use50wt%calcium chloride aqueous solution, Salt effectseparation according to V salting-out agent: V methanol=the proportion of4:3, bestanded60minutes. Then, refine the ethyl acetate according to the quality of theanhydrous calcium chloride (g): the volume of the ethyl acetate (ml)=0.45:10, bemixing40minutes, to get the ethyl acetate in a purity of99.872%(wt), a yield of90.97%.The purpose of extraction rectification stage is to get a lot of methanol and a smallamount of ethyl acetate. This work mainly describes extractive rectification of methanolby using the chemical simulation software Aspen Plus, and optimizes the influencefactors. Finally to get the methanol in a purity of99.75%and the ethyl acetate in apurity of98.68%.As this above process, Separating and recovering methanol-ethylacetate mixed solvent in the optimum conditions, The final simulation result is: thesingle path yield of the gastrodine is100%, ethyl acetate is98.50%, methanol is95.6%;the purity of ethyl acetate is99.76wt%, methanol is99.75wt%, Which all conform tothe enterprise cycle use requirements.