Device and method for separating acetonitrile-water-methanol mixture

Abstract

The invention discloses a device and a method for separating an acetonitrile-water-methanol mixture. The separating device comprises a heating device, a temperature measurement couple, a rectification tower and a product collection tank. The rectification tower, which is located in the heating device, comprises a tower bottom, in which the temperature measurement couple is arranged, a rectification section connected to the tower bottom, a condensing tower above the rectification section, and a liquid transfer tube. The separating method utilizes the device and the differences of solubilities of all components of the mixture in dichloromethane to remove methanol first, the dichloromethane in the lower layer flows back into the rectification tower, and sodium chloride is added into the remaining mixture of acetonitrile and water for breaking and separating the azeotrope to obtain the acetonitrile and the water. The separating device is simple in structure, easy to operate, low in energy consumption, and suitable for industrial production. The device and the method achieve separation of acetonitrile, water and methanol with low costs and energy consumption, and are environmentally friendly and convenient for applications.

Description

[0001] technical field [0002] The invention relates to a separation process of a mixture, in particular to a separation device and a separation method of an acetonitrile-water-methanol mixture. [0003] Background technique [0004] Methanol and acetonitrile are important chemical raw materials and solvents, and they are also important mobile phases in liquid chromatography detection. Therefore, it is easy to produce a mixture of methanol and acetonitrile or a mixture of methanol, acetonitrile and water in the process of chemical production and detection. mixture of components. In order to prevent these mixtures from causing damage to the environment, recovery is usually carried out, and the recovery of the mixture after recovery can be applied here; however, no matter whether it is a two-component mixture or a three-component mixture, it is easy to form an azeotrope under normal pressure, so It is difficult to separate by ordinary distillation methods. [0005] The sep...

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Problems solved by technology

In order to prevent these mixtures from causing damage to the environment, recovery is usually carried out, and the recovery of the mixture after recovery can be applied here; however, no matter whether it is a two-component mixture or a three-component mixture, it is easy to form an azeotrope under normal pressure, so Difficult to separate by ordinary rectification methods

[0005] The separation of the two-component mixture of methanol and acetonitrile is mainly separated by pressure swing rectification. The separation effect of pressure swing rectification is better, but the cost of pressure swing rectification is high, and the temperature of the vacuum tower is too low. consumes a lot of energy

Chinese patent application CN102068831A discloses a batch extraction and rectification separation method of acetonitrile-methanol azeotropic mixture. The extraction and rectification method of adding DMF is used to separate acetonitrile-methanol azeotropic mixture. Although the problem of energy consumption is solved, DMF has relatively High toxicity, potential safety hazard, unfavorable for industrial promotion and application

[0006] For the separation of methanol, acetonitrile and water three-component mixture, it is difficult to achieve the separation effect by pressure swing rectification; since water, methanol and DMF are all miscible, the above method cannot be used to separate the three-component mixture

So far, there is no method for separating the mixture of methanol, acetonitrile and water, so a large part is sold to waste reagent recycling companies for incineration, but acetonitrile incineration is prone to produce highly toxic hydrogen cyanide, which is harmful to environmental damage

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