A composite absorbent and its method for the separation and purification of ethylene oxide

Abstract

The invention provides a composite absorbent and a method for the separation and purification of ethylene oxide. The absorbent includes an ionic liquid and ethylene carbonate, and the structure of the ionic liquid is shown in formula I. The composite absorbent of the present invention contains an ionic liquid with a specific structure, so that when the absorbent is used for the separation and purification of ethylene oxide, it not only has a higher absorption capacity for ethylene oxide but also can significantly increase the absorption capacity of ethylene oxide. The selectivity of alkane absorption and separation can also effectively reduce the vapor pressure of the absorbent and reduce the loss of solvent during the desorption process. It has the characteristics of simple process flow, high operation flexibility, low energy consumption, and significant absorption effect. It has a good industrial application prospect. .

Description

technical field [0001] The invention relates to the technical field of separation, in particular to a composite absorbent and a method for separating and purifying ethylene oxide. Background technique [0002] Ethylene oxide (EO) is an important petrochemical product with excellent sterilization and disinfection effects, and is mainly used in washing, pharmaceutical and printing and dyeing industries. At present, the main production method of ethylene oxide is the ethylene oxidation method, ethylene and oxygen generate ethylene oxide under the condition of silver catalyst, but due to the low conversion rate and selectivity, there will be some The generation of methane, ethane, carbon dioxide and other gases and the existence of ethylene that has not participated in the reaction. In order to produce relatively pure ethylene oxide in industry, water is usually used as the absorbent, and then the relatively pure ring is obtained through desorption, concentration and purificatio...

AI Technical Summary

Problems solved by technology

At present, the main production method of ethylene oxide is the ethylene oxidation method, ethylene and oxygen generate ethylene oxide under the condition of silver catalyst, but due to the low conversion rate and selectivity, there will be some The formation of methane, ethane, carbon dioxide and other gases and the existence of ethylene that has not participated in the reaction. In order to produce relatively pure ethylene oxide in industry, water is usually used as the absorbent, and then the relatively pure ring is obtained through desorption, concentration and purification. Oxyethane

[0003] The water-absorbent process currently has problems such as complex process, poor operating flexibility, and high energy consumption. Many domestic and foreign patents have made improvements to this point.

US3948621A1 discloses using methanol as an absorbent for the separation and purification of ethylene oxide. This absorbent has a good absorption effect and low energy consumption in the desorption process, but methanol is easy to react with ethylene oxide, and the absorption temperature needs to be strictly controlled. Moreover, methanol is easily lost with the volatilization of desorption gas during desorption.

US4221727A1 discloses a method of absorbing and separating ethylene oxide with ethylene carbonate as an absorbent. Using ethylene carbonate as an absorbent not only has a good absorption effect, but also can avoid side reactions during the absorption process. However, during the desorption process, the desorption temperature The temperature is 150℃, and the pressure is 5KPa. At this time, part of ethylene carbonate will volatilize with the desorption gas, resulting in solvent loss.

Similarly, US5559255A discloses the use of propylene carbonate as an absorbent, and CN102911137A discloses a mixture of ethylene carbonate and water as an ethylene oxide absorbent, but neither solves the problem of solvent volatilization loss in the gas stripping process

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