Extraction agent for extracting, rectifying and separating methanol and dimethyl carbonate azeotrope, application of extraction agent, and treatment method

Abstract

The invention provides an extraction agent for extracting, rectifying and separating methanol and dimethyl carbonate azeotrope, application of the extraction agent, and a treatment method. The extraction agent is a mixed extraction agent containing ionic liquid. A system for extracting, rectifying and separating methanol and dimethyl carbonate azeotrope comprises a reaction rectifying tower, an extraction rectifying tower and an extraction agent regeneration tower which are sequentially connected, wherein the extraction rectifying tower uses the extraction agent to perform extraction and rectification. The extraction agent has the advantages that the extraction agent can effectively change the relative volatility of methanol and dimethyl carbonate azeotrope, increase the separation effectof the methanol and dimethyl carbonate azeotrope, the purity of obtained dimethyl carbonate can reach 99.8wt% or above, and the circulating loss rate of the extraction agent can be lowered to 0.01% orbelow; the extraction agent can guarantee the conversion rate of ethylene carbonate and lower the concentration of circulating methanol, and accordingly thermal load is reduced, and separation energyconsumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of organic matter separation, and relates to an extractant for extracting and rectifying the separation of methanol and dimethyl carbonate azeotrope and its use and treatment method. Background technique [0002] Dimethyl carbonate (DMC) is an environmentally friendly green chemical, and is a good methylating agent, carbonylating agent, methylolating agent and methoxylating agent. Because dimethyl carbonate has excellent physical properties such as good compatibility, high octane number and dielectric constant, it can be used as a raw material to develop and prepare a variety of high value-added fine special chemicals, which are used in medicine, pesticides, etc. , synthetic materials, dyes, lubricating oil additives, food flavoring agents and electronic chemicals and other fields have a wide range of applications. In the past ten years, the production and demand of dimethyl carbonate in my country have sho...

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Problems solved by technology

Patent CN 1102826A discloses an improved synthesis method of dialkyl carbonate. By controlling the region where the reaction occurs and using the same ethylene carbonate as the reaction material as the extraction agent, the conversion rate of the transesterification reaction is improved and the product is accelerated. Separation of dialkyl carbonate and alcohol, but the extraction agent is not easy to separate from the product in this method, which increases the energy consumption of extraction agent regeneration

Patent CN 1212172A discloses a method for extracting and rectifying the separation of methanol and dimethyl carbonate azeotrope. This method uses o-xylene as the extraction agent. Although it is beneficial to the separation of dimethyl carbonate and methanol, it introduces other substances At the same time, the regeneration of the extractant and the refining of dimethyl carbonate need to be carried out separately, which increases the energy consumption of the separation

Patent CN 103159586A discloses a dimethyl carbonate-methanol azeotropic mixture continuous extraction rectification separation method, by using the co-product ethylene glycol of the transesterification reaction as the extraction agent to improve the relative volatility of the dimethyl carbonate-methanol system degree, the separated dimethyl carbonate product has high purity and simple operation, but this method is intermittent extraction and rectification, the reflux is relatively large, and the energy consumption is high

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