CN115368236A - Preparation method of ethyl difluoroacetate - Google Patents
Preparation method of ethyl difluoroacetate Download PDFInfo
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- CN115368236A CN115368236A CN202211152366.1A CN202211152366A CN115368236A CN 115368236 A CN115368236 A CN 115368236A CN 202211152366 A CN202211152366 A CN 202211152366A CN 115368236 A CN115368236 A CN 115368236A
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- C07C67/00—Preparation of carboxylic acid esters
- C07C67/27—Preparation of carboxylic acid esters from ortho-esters
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- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C303/00—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides
- C07C303/24—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides of esters of sulfuric acids
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Abstract
The invention relates to the technical field of organic synthesis, in particular to a preparation method of ethyl difluoroacetate, which comprises the following steps: s1, adding 2,2-difluoro-1,1-dichloroethylether into a reaction kettle, dropwise adding concentrated sulfuric acid while stirring at a certain reaction temperature, and after dropwise adding, continuing to perform heat preservation reaction until the reaction is complete to obtain a compound shown in a formula I; s2, adding water into a reaction container, dropwise adding the compound shown in the formula I prepared in the step S1 into the reaction container at a certain temperature for hydrolysis reaction, standing and layering after the reaction is finished, wherein the lower organic layer is ethyl difluoroacetate; the method has the advantages of simple process, easily obtained raw materials, mild reaction conditions, easy control, high product yield and less by-products, can detect the reaction condition at any time, completely avoids secondary recovery treatment in one-time reaction, reduces the loss of the raw materials, and is easy for industrial production.
Description
Technical Field
The invention relates to the technical field of organic synthesis, in particular to a preparation method of ethyl difluoroacetate.
Background
Ethyl difluoroacetate CAS No.: 454-31-9, boiling point: 99 deg.C, colorless transparent liquid, and mellow fragrance.
Ethyl difluoroacetate is an important fluorine-containing fine chemical intermediate, is mainly used for preparing fluorine-containing pesticides and medical products, such as penoxsulam, pyrazole amide bactericides, novel nicotine insecticides, chloramphenicol derivatives, pyrazolothiazines and the like, and is also used as an electrolyte of a lithium battery in recent years.
At present, the synthesis method of the compound is more, and the following methods are mainly used:
1. the difluoroacetyl ethyl ether is subjected to high-temperature catalytic cracking to obtain difluoroacetyl fluoride, and then is subjected to esterification reaction with ethanol to obtain the target product difluoroacetic acid ethyl ester. The method adopts a catalyst for pyrolysis reaction, and has harsh reaction conditions, more side reactions and poor product selectivity.
2. Utilizing difluoroacetonitrile to catalyze, hydrolyze and alcoholyze to obtain the difluoroacetic acid ethyl ester. The reaction raw materials used in the method are not easy to obtain and need to be completed under catalytic conditions.
3. Difluoroacetic acid and ethanol are subjected to esterification reaction to obtain difluoroacetic acid ethyl ester. The method needs to react under an acid catalyst, the reaction yield is low, the raw material loss is large, and the three wastes are complicated to treat.
Reacting 4 dichloroacetyl chloride with diethylamine to generate dichloroacetyl diethylamine, fluorinating to obtain difluoroacetyl diethylamine, and performing acid catalyzed alcoholysis to obtain the target product. In the method, sulfolane is used as a solvent during fluorination, so that sulfur trioxide gas is easily generated, and the method is not favorable for environment, and meanwhile, diethylamine serving as a reaction raw material is difficult to recover, so that the cost is not favorably reduced. The above synthetic methods all suffer from various disadvantages.
Disclosure of Invention
The purpose of the invention is: a process for the preparation of ethyl difluoroacetate is provided, which overcomes at least one of the above technical problems.
In order to realize the purpose, the technical scheme adopted by the invention is as follows:
a preparation method of ethyl difluoroacetate, which comprises the following steps:
s1, adding 2,2-difluoro-1,1-dichloroethylether into a reaction kettle, dropwise adding concentrated sulfuric acid while stirring at a certain reaction temperature, and after dropwise adding, continuing to perform heat preservation reaction until the reaction is complete to obtain a compound shown in a formula I;
s2, adding water into a reaction container, dropwise adding the compound shown in the formula I prepared in the step S1 into the reaction container at a certain temperature for hydrolysis reaction, standing for layering after the reaction is finished, wherein the lower organic layer is ethyl difluoroacetate.
Further, in the step S1, the reaction temperature is controlled to be 10 to 100 ℃ when the concentrated sulfuric acid is dripped, the concentration of the concentrated sulfuric acid is 90 to 98%, and the reaction temperature is controlled to be 30 ℃ after the dripping of the concentrated sulfuric acid is finished to continue the reaction.
Further, when concentrated sulfuric acid is dropwise added in the step S1, the reaction temperature is controlled to be 20-60 ℃, and the concentration of the concentrated sulfuric acid is 90-96%.
Furthermore, the molar ratio of 2,2-difluoro-1,1-dichloroethyl ether to 95% concentrated sulfuric acid is 1:1-2.
Furthermore, the molar ratio of 2,2-difluoro-1,1-dichloroethyl ether to 95% concentrated sulfuric acid is 1.5.
Further, the temperature of the hydrolysis reaction in the step S2 is less than 30 ℃.
The technical scheme adopted by the invention has the beneficial effects that:
compared with the preparation method of ethyl difluoroacetate, the preparation method has the advantages of simple process, easily obtained raw materials, mild reaction conditions, easy control, high product yield and few byproducts, can detect the reaction condition at any time, completely avoids secondary recovery treatment in one-time reaction, reduces the loss of the raw materials, and is easy for industrial production.
The sulfuric acid used in the invention is a reactant, participates in chemical reaction and generates a stable sulfate compound, so that the whole reaction can be carried out at lower temperature and normal pressure, the reaction is thorough, and the yield is high.
Drawings
FIG. 1 is a mass spectrum of a difluoroethyl acetate compound prepared in the present invention.
FIG. 2 is a gas chromatogram of the ethyl difluoroacetate compound prepared in example 1.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the specific embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The raw materials in the invention are all commonly sold in the market.
2,2-difluoro-1,1-dichloroethylether 99% (Jin Jinle (Hunan) Chemicals, inc., jiangsu blue Star environmental protection science, inc.).
A preparation method of ethyl difluoroacetate, which comprises the following steps:
s1, adding 2,2-difluoro-1,1-dichloroethylether into a reaction kettle, dropwise adding concentrated sulfuric acid while stirring at a certain reaction temperature, and after dropwise adding, continuing to perform heat preservation reaction until the reaction is complete to obtain a compound shown in a formula I; the reaction formula is as follows:
s2, adding water into a reaction container, dropwise adding the compound shown in the formula I prepared in the step S1 into the reaction container at a certain temperature for hydrolysis reaction, standing for layering after the reaction is finished, wherein the lower organic layer is ethyl difluoroacetate. The hydrolysis principle is as follows:
the reaction formula (2) and the reaction formula (3) disclose the principle of the process of adding the sulfate compound generated in the reaction formula (1) into water to react to generate ethyl difluoroacetate.
The three reaction formulas completely illustrate the principle that 2,2-difluoro-1,1-dichlorochloroethyl ethyl ether reacts with concentrated sulfuric acid to generate a corresponding sulfuric ester compound, and the sulfuric ester compound is added into water and further reacts to generate an ester compound, thereby providing a basis for improving the production efficiency of the reaction in theory.
FIG. 1 is a mass spectrum of a difluoroethyl acetate compound prepared in the present invention.
FIG. 2 is a gas chromatogram of the ethyl difluoroacetate compound prepared in example 1.
Example 1
179 g of 2,2-difluoro-1,1-dichloroethylether is added into a 1L carbon steel stirring reaction kettle, 155 g of concentrated sulfuric acid with the concentration of 95 percent is dripped under the stirring state, the reaction temperature is controlled below 80 ℃, and after the dripping is finished, the temperature is maintained at about 30 ℃ and the stirring reaction is carried out for 4 hours to obtain the sulfuric ester product, wherein the yield is 99 percent. In the reaction process, tail gas is absorbed by water.
350 g of water is added into a 1L four-neck glass flask with a stirrer, the sulfate compound prepared by the reaction is dripped into a reaction bottle, and the reaction temperature is controlled to be lower than 30 ℃ by a water bath. Standing and layering after the dropwise addition is finished, and separating out 120 g of lower-layer organic matters and 98.6% of ethyl difluoroacetate.
Example 2
200 g of 2,2-difluoro-1,1-dichloroethylether is added into a 1L carbon steel stirring reaction kettle, 223 g of 98% concentrated sulfuric acid is dropwise added under the stirring state, the reaction temperature is controlled below 60 ℃, after the dropwise addition is finished, the temperature is maintained at about 30 ℃, the stirring reaction is carried out for 4 hours, and the sulfate product is obtained, wherein the yield is 99%. In the reaction process, tail gas is absorbed by water.
420 g of water is added into a 1L four-neck glass flask with a stirrer, a sulfate compound prepared by the reaction is dripped into a reaction bottle, and the reaction temperature is controlled to be lower than 30 ℃ by using a water bath. Standing and layering after the dropwise addition is finished, and separating 133 g of lower organic matter with the ethyl difluoroacetate content of 98.5%.
Example 3
350 g of 2,2-difluoro-1,1-dichloroethyl ether is added into a 1L carbon steel stirring reaction kettle, 250 g of concentrated sulfuric acid with the concentration of 92 percent is dripped under the stirring state, the reaction temperature is controlled to be below 60 ℃, and after the dripping is finished, the temperature is maintained to be about 30 ℃ and stirring reaction is carried out for 4 hours to obtain a sulfate product, wherein the yield is 99 percent. In the reaction process, tail gas is absorbed by water.
600 g of water is added into a 2L four-neck glass flask with a stirrer, the sulfate compound prepared by the reaction is dripped into a reaction bottle, and the reaction temperature is controlled to be lower than 30 ℃ by a water bath. Standing and layering after the dropwise addition is finished, and separating out 228 g of lower-layer organic matter with the ethyl difluoroacetate content of 98%.
Example 4
2000 g of 2,2-difluoro-1,1-dichlorochloroethyl ethyl ether is added into a 5 l stirring kettle with a stirred lining of tetrafluoro plastics, 1730 g of 98% concentrated sulfuric acid is dropwise added under the stirring state, the reaction temperature is controlled below 60 ℃, and after the dropwise addition is finished, the temperature is maintained at about 30 ℃ and the stirring reaction is carried out for 2 hours to obtain a sulfuric ester product. Adjusting the reaction device to be a distillation device, dropwise adding 210 g of water into a stirring kettle, maintaining the temperature at 40 ℃ in the dropwise adding process, continuing stirring for 2 hours after the dropwise adding is finished, then heating and distilling, and collecting 1340 g of ethyl difluoroacetate with the boiling point of 99 ℃, wherein the content is 98.8%. After being cooled, the sulfuric acid in the stirring kettle can be continuously used as a raw material for producing a sulfate compound.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment contains only one independent claim, and such description is for clarity only, and those skilled in the art will be able to make the description as a whole, and the embodiments may be appropriately combined to form other embodiments understood by those skilled in the art.
Claims (6)
1. A preparation method of ethyl difluoroacetate is characterized by comprising the following steps: the preparation method comprises the following steps:
s1, adding 2,2-difluoro-1,1-dichloroethylether into a reaction kettle, dropwise adding concentrated sulfuric acid while stirring at a certain reaction temperature, and after dropwise adding, continuing to perform heat preservation reaction until the reaction is complete to obtain a compound shown in a formula I;
s2, adding water into a reaction container, dropwise adding the compound shown in the formula I prepared in the step S1 into the reaction container at a certain temperature for hydrolysis reaction, standing for layering after the reaction is finished, wherein the lower organic layer is ethyl difluoroacetate.
2. The method of claim 1, wherein the method comprises the following steps: in the step S1, the reaction temperature is controlled to be 10-100 ℃ when the concentrated sulfuric acid is dripped, the concentration of the concentrated sulfuric acid is 90-98%, and the reaction temperature is controlled to be 30 ℃ after the dripping of the concentrated sulfuric acid is finished to continue the reaction.
3. The method for preparing ethyl difluoroacetate as claimed in claim 2, characterized in that: in the step S1, the reaction temperature is controlled to be 20-60 ℃ and the concentration of the concentrated sulfuric acid is controlled to be 90-96%.
4. The method of claim 1, wherein the method comprises the following steps: the molar ratio of 2,2-difluoro-1,1-dichloroethylether to 95% concentrated sulfuric acid is 1:1-2.
5. The method of claim 4, wherein the ethyl difluoroacetate is prepared by: the molar ratio of 2,2-difluoro-1,1-dichloroethylether to 95% concentrated sulfuric acid is 1.5.
6. The method of claim 1, wherein the method comprises the following steps: the temperature of the hydrolysis reaction in the step S2 is less than 30 ℃.
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| CN202211152366.1A CN115368236A (en) | 2022-09-21 | 2022-09-21 | Preparation method of ethyl difluoroacetate |
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| CN202211152366.1A CN115368236A (en) | 2022-09-21 | 2022-09-21 | Preparation method of ethyl difluoroacetate |
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