CN-121990908-A - Preparation method of high-purity propylene glycol methyl ether acetate

Abstract

The invention relates to the technical field of high-purity chemicals, and provides a preparation method of high-purity propylene glycol methyl ether acetate. The invention mixes propylene glycol methyl ether, acetic acid and catalyst to carry out first-stage reaction, mixes the obtained first reaction liquid with alkali metal to carry out second-stage reaction, and rectifies the obtained second reaction liquid to obtain the high-purity propylene glycol methyl ether acetate. The invention adds alkali metal into the reaction liquid obtained in the first stage reaction, which not only can reduce the acidity of the product and solve the key problem of higher acidity in the esterification synthesis route of propylene glycol methyl ether acetate, but also can convert unreacted propylene glycol methyl ether into propylene glycol methyl ether alkali metal salt with higher boiling point, and can reduce the separation difficulty of impurities and target products in the subsequent rectification, and in addition, the hydrolysis of the generated propylene glycol methyl ether alkali metal salt can further promote the esterification reaction. The method provided by the invention has the advantages of simple rectification device, high product purity, low water content and wide prospect.

Inventors

• Su Wenjiao
• DU KAIQI
• CHEN GUANGPENG
• WAN SHAOLONG
• HONG WENJING
• HUANG JIAXING

Assignees

• 厦门大学

Dates

Publication Date

20260508

Application Date

20241107

Claims (10)

1. 1. The preparation method of the high-purity propylene glycol methyl ether acetate is characterized by comprising the following steps of: Mixing propylene glycol methyl ether, acetic acid and a catalyst to perform a first-stage reaction to obtain a first reaction liquid; mixing the first-stage reaction liquid with alkali metal to perform a second-stage reaction to obtain a second reaction liquid; and rectifying the second reaction liquid to obtain the high-purity propylene glycol methyl ether acetate.
2. 2. The preparation method of claim 1, wherein the feeding molar ratio of the propylene glycol methyl ether to the acetic acid is 1-10:1.
3. 3. The method of claim 1, wherein the catalyst comprises one or more of a solid acid catalyst resin T-62MP, amberlyst15 catalyzed resin, perfluorosulfonic acid resin HNF-5W, and nkc-9 catalyzed resin.
4. 4. The preparation method of claim 1 or 3, wherein the molar ratio of propylene glycol methyl ether to catalyst is 15-50:1.
5. 5. The method according to claim 1, wherein the first-stage reaction is carried out at a temperature of 60 to 100 ℃ for a time of 1 to 4 hours.
6. 6. The preparation method according to claim 1, wherein the alkali metal comprises one or more of sodium, potassium and lithium, and the molar amount of the alkali metal is 1-5% of the molar amount of propylene glycol methyl ether.
7. 7. The method according to claim 1, wherein the second stage reaction is carried out at a temperature of 80 to 100 ℃ for a reaction time of 0.5 to 4 hours.
8. 8. The preparation method according to claim 1, wherein the rectification operation conditions comprise a feed temperature of 80-120 ℃, a tower bottom temperature of 100-140 ℃, a tower top reflux ratio of 1-3, a reflux ratio in a tower of 5-10 and a pressure of 10-150 kpa, wherein the tower top extract of the rectification comprises water, propylene glycol methyl ether and acetic acid, and the tower extract comprises high-purity propylene glycol methyl ether acetate.
9. 9. The preparation method according to claim 1 or 8, characterized in that the device used in the preparation method comprises a reaction kettle (1); A feed pump (2) communicated with a discharge port of the reaction kettle (1); and a rectifying tower (3) communicated with the outlet of the feed pump (2).
10. 10. The method of claim 1, wherein the high purity propylene glycol methyl ether acetate has a purity of >99.90%, a moisture content of <90mg/L, a propylene glycol methyl ether content of less than or equal to 200ppm, a monometal content of <10ng/L, and a pH of 7±0.1.

Description

Preparation method of high-purity propylene glycol methyl ether acetate Technical Field The invention relates to the technical field of electronic chemicals, in particular to a preparation method of high-purity propylene glycol methyl ether acetate. Background With the rapid growth of the global electronics industry, electronic chemicals as their core materials, market demand continues to grow. The high-purity propylene glycol methyl ether acetate has very wide dissolving capacity, is a high-grade industrial solvent with low toxicity and excellent performance, has wide application in the field of electronic elements, and can be used in the manufacturing process of liquid crystal displays, semiconductors and the like. Because of the special requirements in the field of electronic components, high purity propylene glycol methyl ether acetate requires extremely low levels of moisture and acidic impurities. Based on the problems of operation cost and production cost, an esterification synthesis route is generally adopted, propylene glycol methyl ether (PM) and acetic acid are used as raw materials to produce propylene glycol methyl ether acetate, but the method can generate a large amount of water, the used acid raw materials and catalyst can lead to higher system acidity, and larger cost is required to be input in the aspect of post-treatment. At present, propylene glycol methyl ether acetate is generally purified by adopting a rectification method, and the rectification method is a process of separating each component by utilizing different volatilities of each component in a mixture, but a plurality of rectification towers are commonly used for series purification in industry, so that not only is energy consumption and cost high, but also the process is complex, and the high-purity product is difficult to effectively obtain by simple rectification. The Chinese patent with publication number CN107098810A discloses a purification method of high-purity propylene glycol methyl ether acetate, wherein light components in a product are removed by a rectification mode of a main tower with a side tower, meanwhile, a dehydration tower is combined, toluene is adopted as an entrainer, rectification is carried out under normal pressure, the acidity content of the product is less than 80ppm, but the method is complex in post-treatment, and the entrainer toluene used in the method has strong toxicity and is easy to pollute the environment. The Chinese patent publication No. CN101693661A discloses a method for producing propylene glycol methyl ether acetate, wherein after the reaction is finished, products and unreacted materials are distilled off and then pass through an acid catcher, an acid catalyst is recovered, gas-phase materials enter a reaction rectifying tower, an entrainer is added at the upper part of the reaction rectifying tower to remove water in the materials azeotropically, and residual acetic acid in the materials is reacted under the action of a layered solid acid catalyst in a reaction section of the reaction rectifying tower. The acidity of the product in the patent reaches 0.0085%, but the method needs to adopt an acid catcher, and a layered solid catalyst needs to be installed at the lower part of a feed inlet of a rectifying tower, so that the device is complex and the cost is high. The Chinese patent with publication number CN114702385A discloses a production method and a device of electronic grade propylene glycol methyl ether acetate, the device comprises a precise rectifying tower, a microfilter, an anion-cation remover, a dehydration processor and a nanofiltration device, the precise rectifying tower comprises a partition tower string for precise rectification, the partition tower string comprises a partition tower with an upper partition and a partition tower with a middle partition which are connected in series, the precise rectifying tower is adopted to remove organic impurities and a small amount of water in the industrial grade propylene glycol methyl ether acetate, the dehydration processor is used to remove most of water, the process continuity is strong, but the two rectifying towers are used for separation and purification, and the energy consumption and the cost are high. In summary, the existing preparation methods of the high-purity propylene glycol methyl ether acetate have the problems of complex operation, high energy consumption and environmental pollution, and the development of the high-efficiency, environment-friendly and economic separation and purification technology of the high-purity propylene glycol methyl ether acetate has great significance for improving the quality of electronic products and promoting the sustainable development of industries. Disclosure of Invention In view of this, the present invention provides a method for preparing propylene glycol methyl ether acetate with high purity. The preparation method provided by the invention is simple to operate, low in c