Method for producing ethyl acetate with coupled reaction distillation and permeation steam generation

Abstract

The invention relates to a method for producing ethyl acetate by reaction rectification and pervaporation coupling. The method is as follows: raw materials, namely acetic acid and ethanol are catalyzed in a reaction rectification tower and rectified, an organic phase is separated out from the distillate at the top of the tower and passes through a pervaporation permeable film component, wherein the contained water and ethanol selectively permeate the film and then enrich on the permeable side of the film to be removed; the ethyl acetate is obtained from the non-permeable side of the film; and part of the ethyl acetate as dehydrating agent is returned to the reaction rectification tower while the rest as a product is extracted; at the same time, part of liquor extracted from the tower bottom of the reaction rectification tower is introduced into another pervaporation permeable film component, the contained moisture is enriched on the permeable side of the film to be separated and removed, the ethyl acetate is obtained from the non-permeable side of the film, and the ethyl acetate is circularly returned to an acetic acid feeding hole of the reaction rectification tower. Compared with the prior art, the method can reduce reflux ratio greatly, has the advantages of simple technical route, energy saving, environmental protection and compact device, and reduces equipment investment and production cost for the ethyl acetate remarkably.

Description

technical field [0001] The invention relates to a process for producing ethyl acetate coupled with reactive distillation and pervaporation. Background technique [0002] Ethyl acetate is an important fine chemical raw material, widely used in paints, coatings, artificial leather, nitrocellulose, adhesives, medicine and other fields. In recent years, the application of ethyl acetate at home and abroad has grown rapidly. With the further improvement of environmental protection requirements for domestic coatings and adhesive products, ethyl acetate has been widely used as a non-toxic solvent. It has been gradually used in my country's coating industry. Environmentally friendly coatings, therefore, will further drive the market growth of ethyl acetate. [0003] The alkyd esterification method used by domestic ethyl acetate manufacturers is generally a continuous method, that is, the production device consists of an esterification tower, a dehydration tower, a refining tower and ...

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Problems solved by technology

[0003] The alkyd esterification method used by domestic ethyl acetate manufacturers is generally a continuous method, that is, the production device consists of an esterification tower, a dehydration tower, a refining tower and a recovery tower. The process is characterized by the esterification reaction being carried out in the esterification tank. The separation process mainly adopts the azeotropic distillation process for dehydration and dealcoholization. Due to the characteristics of the ethyl acetate-water-ethanol ternary azeotropic system, the water content in the reflux of the organic phase at the top of the esterification tower is relatively high, so the ability of the reflux to carry water is poor , usually the reflux ratio of the esterification tower is around 3 to 5; the same reason causes the water content in the crude ester entering the dehydration tower to be relatively high. The yield of the ester, the reflux ratio of the top of the tower is usually more than 7; in addition, in order to reduce the consumption of ethanol, the organic phase separated from the mixture containing ethyl acetate, ethanol and water extracted from the top of the dehydration tower is returned to the esterification The tower kettle continues to participate in the reaction, causing a part of the water to circulate in the esterification and dehydration process; the total energy consumption of these two towers accounts for more than 4 / 5 of the entire process energy consumption; due to the relatively large gas-liquid phase load of the two towers, production Ability is also limited

Although some researchers have proposed a reactive distillation-extractive distillation process, the addition of a third component with a high boiling point still consumes a lot of energy in extractive distillation

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