Method for preparing 1, 1-ethylene glycol diacetate

Abstract

The invention discloses a method for preparing 1, 1-ethylene glycol diacetate, which is characterized by comprising the following steps: by taking acetic acid and vinyl acetate as raw materials, carrying out reflux reaction at 80-85 DEG C in the presence of a catalyst, after the reaction is finished, stopping heating, adding sodium acetate into a reaction container, continuing the reaction to neutralize the catalyst, and after the reaction is finished, separating the solid in the mixed solution to obtain the 1, 1-ethylene glycol diacetate. The target product 1, 1-ethylene glycol diacetate is obtained through liquid phase concentration, and the catalyst is at least one of concentrated sulfuric acid, methanesulfonic acid and p-toluenesulfonic acid. The raw materials are safe and environment-friendly, the price is low, the reaction can be carried out under normal pressure, the requirement on equipment is low, industrial production is easy, the yield is high, and the purity is high.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing 1,1-ethylene glycol diacetate. Background Art

[0002] 1,1-Ethylene glycol diacetate, its molecular formula is C6H 10 O4, relative molecular mass is 146.14,

[0003] Its structural formula is:

[0004] Most of the methods for synthesizing 1,1-ethylene glycol diacetate at home and abroad use acetic anhydride, acetaldehyde or acetylene as raw materials for the reaction. However, in this method, acetic anhydride is easy to make poison and difficult to buy; while acetaldehyde or acetylene has a low boiling point, and the reaction is often carried out in an autoclave, which has high requirements for equipment.

[0005] 1,1-Ethylene glycol diacetate is also a by-product in the reaction process of vinyl carboxylate (through purification of the by-product, nuclear magnetic resonance and other technical analysis, it was finally determined that the by-product 1,1-ethylene glycol diacetate existed) and by-products such as flurbiprofen axetil. Its presence will lead to a decrease in product yield and also have an important impact on product quality. Therefore, this substance with high purity is also needed as a standard substance for performance research and quality research.

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

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

[0008] (2) cooling the reaction mixture and filtering the mixture, and concentrating the filtrate to obtain a crude product of flurbiprofen axetil impurity 1,1-ethylene glycol diacetate;

[0009] (3) The crude product is separated by a column to obtain high-purity flurbiprofen axetil impurity 1,1-ethylene glycol diacetate, eluted with an eluent, and the solvent is evaporated under reduced pressure to obtain flurbiprofen axetil impurity 1,1-ethylene glycol diacetate. This method is a substitution reaction, and the prepared 1,1-ethylene glycol diacetate has a low yield and low purity, and needs to be passed through a column to obtain a pure product. Summary of the invention

[0010] In order to solve the above technical problems, the present invention provides another method for preparing 1,1-ethylene glycol diacetate, which has safe and environmentally friendly raw materials, low price, can be reacted under normal pressure, has low requirements on equipment, is easy to industrialize, has high yield and high purity.

[0011] To achieve the above objectives, the present invention is implemented by the following technical scheme: a method for preparing 1,1-ethylene glycol diacetate, characterized in that: acetic acid and vinyl acetate are used as raw materials, and a reflux reaction is carried out at 80-85° C. in the presence of a catalyst. After the reaction is completed, the heating is turned off, glacial acetic acid is added into the reaction container, and the reaction is continued to neutralize the catalyst. After the reaction is completed, the solid in the mixed liquid is separated, and the liquid phase is concentrated to obtain the target product 1,1-ethylene glycol diacetate, and 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 added amount of the catalyst 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 3-4h.

[0018] In the above scheme: the reaction time of adding sodium acetate is 20-30min.

[0019] The present invention uses raw materials acetic acid and vinyl acetate to carry out addition reaction under specific catalyst conditions, and then obtains the target product through neutralization, filtration and distillation. The reaction equation is as follows:

[0020]

[0021] In the present invention, raw materials acetic acid and vinyl acetate undergo addition reaction under the action of a catalyst to obtain the target product 1,1-ethylene glycol diacetate. The target product is extremely unstable under the catalyst and is easily cracked at high temperature to obtain vinyl acetate and acetic acid. Therefore, we select a temperature of 80-85°C for the reaction, and after the reaction is completed, sodium acetate is immediately added for neutralization reaction to neutralize the catalyst and avoid decomposition.

[0022] In the present invention, the raw material is acetic acid, and the catalyst is one or more mixtures of sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, etc. In the neutralization step, when a base such as sodium hydroxide is selected as a neutralizing agent, the unreacted acetic acid is subjected to a neutralization reaction to generate acetate and water, which places too high requirements on post-processing. In the present invention, sodium acetate is selected as a neutralizing agent, and sodium acetate reacts with the catalyst to generate salt and acetic acid. The solid salt in the system can be separated by filtration, and no new components, especially water, are introduced into the system, which is convenient for subsequent distillation and purification.

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

[0024] The present invention uses acetic acid and vinyl acetate to react, and the raw materials are cheap and easy to obtain. The reaction is carried out under normal pressure, and the equipment requirements are relatively low. After the reaction is completed, the catalyst is neutralized by sodium acetate, and then centrifugal filtration and distillation are performed to obtain the target product 1,1-ethylene glycol diacetate, and the yield can reach more than 90%. The process is simple and convenient, and it is suitable for industrial production. The 1,1-ethylene glycol diacetate synthesized by the process of the present invention has a yield of more than 90% and a purity of more than 99.0%. The process is simple and convenient, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the GC chart of the product of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Example 1

[0028] Add 100g acetic acid and 170g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 6.6g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 220g of 1,1-ethylene glycol diacetate with a content of 99.2%.

[0029] Example 2

[0030] Add 100g acetic acid and 170g vinyl acetate to the reactor, start stirring, add 10g p-toluenesulfonic acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 6g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 228g of 1,1-ethylene glycol diacetate with a content of 99.1%.

[0031] Example 3

[0032] 100g of acetic acid and 170g of vinyl acetate were added to the reactor, and after stirring, 6.6g of concentrated sulfuric acid was added thereto, and heating was started, and the reactor temperature was kept at 80°C for reflux reaction for 4h. After the reaction was completed, it was purified by distillation to obtain 86g of the product 1,1-ethylene glycol diacetate with a content of 99.0%.

[0033] Example 4

[0034] Add 100g acetic acid and 143g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 7g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 223g of 1,1-ethylene glycol diacetate with a content of 99.2%.

[0035] Example 5

[0036] Add 100g acetic acid and 214g vinyl acetate to the reactor, start stirring, add 15.7g concentrated sulfuric acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 13g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 219g of 1,1-ethylene glycol diacetate with a content of 99.3%.

[0037] Example 6

[0038] Add 100g acetic acid and 170g vinyl acetate to the reactor, start stirring, add 2.7g concentrated sulfuric acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 2.7g sodium acetate and react for 20min. After filtering, the organic phase is purified by distillation to obtain 218g of 1,1-ethylene glycol diacetate with a content of 99.3%.

[0039] Example 7

[0040] Add 100g acetic acid and 170g vinyl acetate to the reactor, start stirring, add 10.8g methanesulfonic acid, start heating, keep the reactor temperature at 85°C and reflux for 3h. After the reaction is completed, add 11g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 223g of 1,1-ethylene glycol diacetate with a content of 99.1%.

[0041] Example 8

[0042] Add 100g acetic acid and 143g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 8.3g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 219g of 1,1-ethylene glycol diacetate with a content of 99.3%.

[0043] Example 9

[0044] Add 100g acetic acid and 143g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 80°C and reflux for 4h. After the reaction is completed, add 20g sodium hydroxide solution (45%) and react for 30min. After filtering, the organic phase is purified by distillation to obtain 98g of 1,1-ethylene glycol diacetate with a content of 80.8%.

[0045] Example 10

[0046] Add 100g acetic acid and 143g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 90°C and reflux for 4h. After the reaction is completed, add 7g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 158g of 1,1-ethylene glycol diacetate with a content of 93%.

[0047] Embodiment 11

[0048] Add 100g acetic acid and 143g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 100°C and reflux for 4h. After the reaction is completed, add 7g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 108g of 1,1-ethylene glycol diacetate with a content of 92%.

[0049] Example 12

[0050] Add 100g acetic acid and 143g vinyl acetate to the reactor, start stirring, add 6.6g concentrated sulfuric acid, start heating, keep the reactor temperature at 70°C and react for 12h. After the reaction is completed, add 7g sodium acetate and react for 30min. After filtering, the organic phase is purified by distillation to obtain 182g of 1,1-ethylene glycol diacetate with a content of 95.7%.

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

Claims

1. A method for preparing 1,1-ethylene glycol diacetate, characterized in that: Acetic acid and vinyl acetate are used as raw materials, and a reflux reaction is carried out at 80-85° C. in the presence of a catalyst. After the reaction is completed, the heating is turned off, and sodium acetate is added into the reaction container to continue the reaction to neutralize the catalyst. After the reaction is completed, the solid in the mixed liquid 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 to 3, characterized in that: The added amount of the catalyst 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 the sodium acetate to the 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 the sodium acetate to the 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 h.

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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