A process for the preparation of 1,1-ethylene glycol diacetate

Abstract

This invention discloses a method for preparing 1,1-ethylene glycol diacetate, characterized by: using acetic acid and vinyl acetate as raw materials, reacting under reflux at 80-85°C in the presence of a catalyst; after the reaction is complete, turning off the heating, adding sodium acetate to the reaction vessel, continuing the reaction to neutralize the catalyst; after the reaction is complete, separating the solid from the mixture, and concentrating the liquid phase to obtain the target product 1,1-ethylene glycol diacetate. The catalyst is at least one selected from concentrated sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid. The raw materials are safe and environmentally friendly, inexpensive, and can be reacted under normal pressure, requiring less sophisticated equipment, facilitating industrial production, and yielding high purity.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a method for preparing 1,1-ethylene glycol diacetate. Background Technology

[0002] 1,1-Ethylene glycol diacetate, with the molecular formula C6H 10 O4 has a relative molecular mass of 146.14.

[0003] Its structural formula is:

[0004] Most methods for synthesizing 1,1-ethylene glycol diacetate, both domestically and internationally, use acetic anhydride, acetaldehyde, or acetylene as raw materials. However, acetic anhydride is a readily available toxic substance and difficult to obtain; while acetaldehyde or acetylene have low boiling points, and the reaction is often carried out in a high-pressure reactor, requiring sophisticated equipment.

[0005] 1,1-Ethylene glycol diacetate is also a byproduct of the reaction of ethylene carboxylic acid esters (through purification and analysis of this byproduct using techniques such as nuclear magnetic resonance, the presence of 1,1-ethylene glycol diacetate was finally confirmed) and a byproduct of flurbiprofen esters. Its presence leads to a decrease in product yield and also has a significant impact on product quality. Therefore, this substance with high purity is needed as a standard for performance and quality studies.

[0006] CN 117623922 A discloses a method for preparing 1,1-ethylene glycol diacetate and its application, the method comprising the following steps:

[0007] (1) Add acetic acid and 1-haloethyl acetate to an organic solvent and stir until clear, then add 1-5 eq of base to react;

[0008] (2) Cool down and filter the above reaction, concentrate the filtrate to obtain crude flurbiprofen ester impurity 1,1-ethylene glycol diacetate;

[0009] (3) The crude product was separated by column chromatography to obtain high-purity flurbiprofen ester impurity 1,1-ethylenediacetate. The product was eluted with an eluent, and the solvent was evaporated under reduced pressure to obtain flurbiprofen ester impurity 1,1-ethylenediacetate. This method is a substitution reaction, and the prepared 1,1-ethylenediacetate has a low yield and low purity, requiring column chromatography to obtain a pure product. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides another method for preparing 1,1-ethylene glycol diacetate. The raw materials are safe, environmentally friendly, and inexpensive. The reaction can be carried out under normal pressure, requiring less sophisticated equipment, making it easy to industrialize, and yielding high purity.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solution: a method for preparing 1,1-ethylene glycol diacetate, characterized in that: acetic acid and vinyl acetate are used as raw materials, and the mixture is refluxed at 80-85°C in the presence of a catalyst. After the reaction is complete, heating is turned off, glacial acetic acid is added to the reaction vessel, and the reaction continues to neutralize the catalyst. After the reaction is completed, the solid in the mixture is separated, and the liquid phase is concentrated to obtain the target product 1,1-ethylene glycol diacetate. The catalyst is at least one of concentrated sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid.

[0012] In the above scheme, the molar ratio of acetic acid to vinyl acetate is 1:1-1.5.

[0013] In the above scheme, the molar ratio of acetic acid to vinyl acetate is 1:1.2.

[0014] In the above scheme, the amount of catalyst added is 1-5% of the total mass of acetic acid and vinyl acetate.

[0015] In the above scheme, the molar ratio of sodium acetate to catalyst is 1-1.5:1.

[0016] In the above scheme, the molar ratio of sodium acetate to catalyst is 1.2:1.

[0017] In the above scheme, the reaction time in the presence of a catalyst is 3-4 hours.

[0018] In the above scheme, the reaction time for adding sodium acetate is 20-30 minutes.

[0019] This invention utilizes acetic acid and vinyl acetate as raw materials, undergoing an addition reaction under specific catalytic conditions, followed by neutralization, filtration, and distillation to obtain the target product. The reaction equation is as follows:

[0020]

[0021] In this invention, acetic acid and vinyl acetate undergo an addition reaction under the action of a catalyst to obtain the target product, 1,1-ethylene glycol diacetate. This target product is extremely unstable under the catalyst and easily undergoes decomposition at high temperatures, yielding vinyl acetate and acetic acid. Therefore, we choose a reaction temperature of 80-85℃, and immediately after the reaction, sodium acetate is added for neutralization to neutralize the catalyst and prevent decomposition.

[0022] In this invention, the raw material is acetic acid, and the catalyst is one or a mixture of sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, etc. In the neutralization step, when a base such as sodium hydroxide is chosen as the neutralizing agent, it will react with the unreacted acetic acid to produce acetate and water, which places excessive demands on post-treatment. In this invention, sodium acetate is chosen as the neutralizing agent. Sodium acetate reacts with the catalyst to produce salt and acetic acid. Subsequent filtration can separate the solid salt from the system without introducing new components, especially water, facilitating subsequent distillation and purification.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] This invention utilizes the reaction of acetic acid and vinyl acetate, using inexpensive and readily available raw materials. The reaction is conducted under normal pressure, requiring minimal equipment. After the reaction, the catalyst is neutralized with sodium acetate, followed by centrifugation, filtration, and distillation to obtain the target product, 1,1-ethylene glycol diacetate, with a yield exceeding 90%. The process is simple, convenient, and suitable for industrial production. The 1,1-ethylene glycol diacetate synthesized using this invention achieves a yield exceeding 90% and a purity exceeding 99.0%. The process is simple, convenient, and suitable for industrial production. Attached Figure Description

[0025] Figure 1 This is a GC diagram of the product of the present invention. Detailed Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0027] Example 1

[0028] 100g of acetic acid and 170g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 6.6g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 220g of 1,1-ethylene glycol diacetate with a purity of 99.2%.

[0029] Example 2

[0030] 100g of acetic acid and 170g of vinyl acetate were added to a reaction vessel. After stirring, 10g of p-toluenesulfonic acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 6g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 228g of 1,1-ethylene glycol diacetate with a purity of 99.1%.

[0031] Example 3

[0032] 100g of acetic acid and 170g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and heating was started. The vessel was refluxed at 80℃ for 4 hours. After the reaction was completed, the product 1,1-ethylene glycol diacetate was purified by distillation to obtain 86g of product with a purity of 99.0%.

[0033] Example 4

[0034] 100g of acetic acid and 143g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 7g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 223g of 1,1-ethylene glycol diacetate with a purity of 99.2%.

[0035] Example 5

[0036] 100g of acetic acid and 214g of vinyl acetate were added to a reaction vessel. After stirring, 15.7g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 13g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 219g of 1,1-ethylene glycol diacetate with a purity of 99.3%.

[0037] Example 6

[0038] 100g of acetic acid and 170g of vinyl acetate were added to a reaction vessel. After stirring, 2.7g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 2.7g of sodium acetate was added, and the reaction was allowed to proceed for 20 minutes. After filtration, the organic phase was purified by distillation to obtain 218g of 1,1-ethylene glycol diacetate with a purity of 99.3%.

[0039] Example 7

[0040] 100g of acetic acid and 170g of vinyl acetate were added to a reaction vessel. After stirring, 10.8g of methanesulfonic acid was added, and the vessel was heated and refluxed at 85℃ for 3 hours. After the reaction was complete, 11g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 223g of 1,1-ethylene glycol diacetate with a purity of 99.1%.

[0041] Example 8

[0042] 100g of acetic acid and 143g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 8.3g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 219g of 1,1-ethylene glycol diacetate with a purity of 99.3%.

[0043] Example 9

[0044] 100g of acetic acid and 143g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 80℃ for 4 hours. After the reaction was complete, 20g of sodium hydroxide solution (45%) was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 98g of 1,1-ethylene glycol diacetate with a purity of 80.8%.

[0045] Example 10

[0046] 100g of acetic acid and 143g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 90℃ for 4 hours. After the reaction was complete, 7g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 158g of 1,1-ethylene glycol diacetate with a purity of 93%.

[0047] Example 11

[0048] 100g of acetic acid and 143g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and the vessel was heated and refluxed at 100℃ for 4 hours. After the reaction was complete, 7g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. After filtration, the organic phase was purified by distillation to obtain 108g of 1,1-ethylene glycol diacetate with a purity of 92%.

[0049] Example 12

[0050] 100g of acetic acid and 143g of vinyl acetate were added to a reaction vessel. After stirring, 6.6g of concentrated sulfuric acid was added, and heating was initiated, maintaining the vessel temperature at 70℃ for 12 hours. After the reaction was complete, 7g of sodium acetate was added, and the reaction was allowed to proceed for 30 minutes. The mixture was then filtered, and the organic phase was purified by distillation to obtain 182g of 1,1-ethylene glycol diacetate with a purity of 95.7%.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing 1,1-ethylene glycol diacetate, characterized in that: Using acetic acid and vinyl acetate as raw materials, the mixture is refluxed at 80-85°C in the presence of a catalyst. After the reaction is complete, the heating is turned off, and sodium acetate is added to the reaction vessel to continue the reaction and neutralize the catalyst. After the reaction is complete, the solid in the mixture is separated, and the liquid phase is concentrated to obtain the target product 1,1-ethylene glycol diacetate. The catalyst is at least one of concentrated sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid.

2. The method for preparing 1,1-ethylene glycol diacetate according to claim 1, characterized in that: The molar ratio of acetic acid to vinyl acetate is 1:1-1.

5.

3. The method for preparing 1,1-ethylene glycol diacetate according to claim 2, characterized in that: The molar ratio of acetic acid to vinyl acetate is 1:1.

2.

4. The method for preparing 1,1-ethylene glycol diacetate according to any one of claims 1-3, characterized in that: The amount of catalyst added is 1-5% of the total mass of acetic acid and vinyl acetate.

5. The method for preparing 1,1-ethylene glycol diacetate according to claim 4, characterized in that: The molar ratio of sodium acetate to catalyst is 1-1.5:

1.

6. The method for preparing 1,1-ethylene glycol diacetate according to claim 5, characterized in that: The molar ratio of sodium acetate to catalyst is 1.2:

1.

7. The method for preparing 1,1-ethylene glycol diacetate according to claim 1, characterized in that: The reaction time in the presence of a catalyst is 3-4 hours.

8. The method for preparing 1,1-ethylene glycol diacetate according to claim 7, characterized in that: The reaction time for adding sodium acetate is 20-30 minutes.

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