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CN-122010736-A - Dehydration and purification method and system for industrial grade dimethyl carbonate

CN122010736ACN 122010736 ACN122010736 ACN 122010736ACN-122010736-A

Abstract

A dehydration purification method and system of industrial grade dimethyl carbonate relates to the field of purification of dimethyl carbonate, wherein the purification method comprises the steps of mixing industrial grade dimethyl carbonate, dehydrating agent and adsorbent according to the mass ratio of 1 (0.05-0.07), sending the obtained reaction product into a rectifying tower for rectifying separation, and obtaining electronic grade dimethyl carbonate from the tower bottom of the rectifying tower, wherein the dehydrating agent is one or a combination of two of sodium methoxide and sodium ethoxide, and the adsorbent is one or a combination of more than two of A type molecular sieve, silicon-aluminum-phosphorus molecular sieve and KCC type molecular sieve. The invention can accurately meet the strict use requirement of electronic grade DMC on water content and purity, the water content is not more than 10ppm, the purity is not less than 99.999%, and the invention provides high-quality raw material guarantee for the field of electronic chemical industry.

Inventors

  • ZHANG XIANLEI

Assignees

  • 上海派胜信息科技有限公司

Dates

Publication Date
20260512
Application Date
20260115

Claims (10)

  1. 1. A dehydration purification method of industrial grade dimethyl carbonate is characterized in that industrial grade dimethyl carbonate, a dehydrating agent and an adsorbent are mixed to react according to the mass ratio of 1 (0.05-0.07) to 0.05-0.07, the obtained reaction product is sent into a rectifying tower to carry out rectifying separation, and electronic grade dimethyl carbonate is obtained from the tower bottom of the rectifying tower; Wherein the dehydrating agent is one or the combination of two of sodium methoxide and sodium ethoxide, and the adsorbent is one or the combination of more than two of A-type molecular sieve, silicon-aluminum-phosphorus molecular sieve and KCC-type molecular sieve.
  2. 2. The method for dehydrating and purifying industrial grade dimethyl carbonate according to claim 1, wherein the temperature of the mixing reaction is 60-80 ℃ and the reaction time is 2-4h.
  3. 3. The method for dehydrating and purifying industrial grade dimethyl carbonate according to claim 1, wherein stirring is carried out during the mixing reaction, and the stirring speed is 150-250r/min.
  4. 4. The process for the dehydration and purification of technical grade dimethyl carbonate according to claim 1, wherein the obtained reaction product is heated to 70-85 ℃ and fed into a rectifying tower.
  5. 5. The method for dehydrating and purifying industrial grade dimethyl carbonate according to claim 1, wherein the pressure at the top of the rectifying tower is 0.95-0.1MPa, the temperature at the top of the rectifying tower is 62-65 ℃, and the reflux ratio at the top of the rectifying tower is 1-5.
  6. 6. The method for dehydrating and purifying industrial grade dimethyl carbonate according to claim 1, wherein the temperature of the bottom of the rectifying tower is 87-91 ℃.
  7. 7. The dehydration purification method of technical grade dimethyl carbonate according to claim 1, wherein the dehydrating agent is sodium methoxide, the adsorbent is A-type molecular sieve, the temperature of the mixing reaction is 60 ℃, the reaction time is 2h, stirring is carried out in the mixing reaction process, the stirring speed is 150r/min, the obtained reaction product is heated to 80 ℃ and sent into a rectifying tower, the tower top pressure of the rectifying tower is 0.1MPa, the tower top temperature is 65 ℃, the tower top reflux ratio is 2, and the tower bottom temperature is 90 ℃.
  8. 8. The method for dehydrating and purifying industrial grade dimethyl carbonate according to claim 1, wherein the rectifying tower is one or a combination of two of silk screen corrugated packing and orifice plate corrugated packing.
  9. 9. The dehydration and purification system of the industrial grade dimethyl carbonate is characterized by comprising a stirring reaction kettle (2) and a rectifying tower (6); the discharge port of the stirring reaction kettle (2) is connected with the feed port of the rectifying tower (6) through a reaction product conveying pipeline (3); The top of the rectifying tower (6) is provided with a tower top distillate conveying pipeline (7), the tail end of the tower top distillate conveying pipeline (7) is connected with a tower top condensing tank (9), the tower top condensing tank (9) is connected with two material discharging pipelines, one material discharging pipeline is communicated with the upper part of the rectifying tower (6), and the other material discharging pipeline is used for outputting tower top products; The bottom of rectifying column (6) is provided with tower cauldron distillate transfer line (11), and tower cauldron distillate transfer line (11) divide to set up two branch pipelines, and wherein a branch pipeline communicates with rectifying column (6) lower part, and another branch pipeline is used for exporting electronic grade dimethyl carbonate.
  10. 10. The dehydration and purification system of industrial grade dimethyl carbonate according to claim 9, wherein a first heat exchanger (5) is arranged on a reaction product conveying pipeline (3), a second heat exchanger (8) is arranged on an overhead product conveying pipeline (7), and a reboiler (12) is arranged on a branch pipeline communicated with the lower part of the rectifying tower (6).

Description

Dehydration and purification method and system for industrial grade dimethyl carbonate Technical Field The invention relates to the field of purification of dimethyl carbonate, in particular to a dehydration purification method and a dehydration purification system of industrial grade dimethyl carbonate. Background Dimethyl carbonate (DimethylCarbonate, DMC for short) is widely applied to the fields of lithium battery electrolyte solvents, electronic component cleaning, photoetching technology, environment-friendly paint and ink, medical intermediate synthesis, fuel additives and the like, has both environment friendliness and high efficiency, and is a key raw material for promoting the development of new energy, semiconductors and green chemical industry. DMC is used as an indispensable organic solvent in the electronic industry and the battery industry, plays a key role in the production of lithium battery electrolyte, and electrolyte is used as a core material of a lithium ion battery, and the performance of the electrolyte is highly dependent on the quality of the solvent in a formula, especially the water content, the total alcohol content and the content of other impurity components of electronic grade dimethyl carbonate, and the factors directly relate to the performance of the electrolyte, so that various indexes of the battery are influenced, and the quality requirements of the market on the electronic grade dimethyl carbonate are increasingly severe. At present, industrial grade DMC which is a byproduct of the domestic coal-to-ethylene glycol industry has great potential for preparing electronic grade DMC, but because of a plurality of impurity types and a complex azeotropic system, the traditional technology is difficult to separate and obtain a high-purity (99.99%) product. In the prior art, chinese patent CN115228119a discloses a system and a method for purifying dimethyl carbonate, and the disclosed purifying system includes an adsorption tower and a rectification unit, and obtains high-purity dimethyl carbonate by a combination of adsorption and rectification. Chinese patent CN113121346a discloses a purification method of electronic grade dimethyl carbonate, which adopts a rectification-adsorption coupling process to purify industrial grade dimethyl carbonate into 99.99% electronic grade dimethyl carbonate product. The prior art has complex process flow, high energy consumption in the process of producing high-purity products, and high adsorbent consumption, and the purity of the obtained dimethyl carbonate product needs to be further improved. Disclosure of Invention The invention aims to provide a dehydration purification method and a dehydration purification system of industrial grade dimethyl carbonate, by constructing a multi-process deep coupling system integrating the functions of reaction, adsorption and rectification, the system can accurately meet the severe use requirements of electronic grade DMC on water content and purity in industrial production scenes, the water content is less than 10ppm, the purity is less than 99.999%, and high-quality raw material guarantee is provided for the field of electronic chemical industry. In order to solve the technical problems, the invention adopts the specific scheme that the dehydration and purification method of the industrial grade dimethyl carbonate comprises the steps of mixing and reacting the industrial grade dimethyl carbonate, a dehydrating agent and an adsorbent according to the mass ratio of 1 (0.05-0.07): 0.05-0.07, sending the obtained reaction product into a rectifying tower for rectifying and separating, and obtaining the electronic grade dimethyl carbonate from the tower bottom of the rectifying tower; Wherein the dehydrating agent is one or the combination of two of sodium methoxide and sodium ethoxide, and the adsorbent is one or the combination of more than two of A-type molecular sieve, silicon-aluminum-phosphorus molecular sieve and KCC-type molecular sieve. As a further optimization of the technical scheme, the temperature of the mixing reaction is 60-80 ℃ and the reaction time is 2-4h. As a further optimization of the technical scheme, stirring is carried out during the mixing reaction, and the stirring speed is 150-250r/min. As a further optimization of the technical scheme, the obtained reaction product is heated to 70-85 ℃ and is sent to a rectifying tower. As a further optimization of the technical scheme, the pressure at the top of the rectifying tower is 0.95-0.1MPa, the temperature at the top of the rectifying tower is 62-65 ℃ and the reflux ratio at the top of the rectifying tower is 1-5. As a further optimization of the technical scheme, the temperature of the tower bottom of the rectifying tower is 87-91 ℃. The technical scheme is further optimized in that the dehydrating agent is sodium methoxide, the adsorbent is an A-type molecular sieve, the temperature of the mixing reaction is 60 ℃, the reaction time is 2