A kind of preparation method and reaction device of difluoroethyl acetate

Abstract

The invention discloses a preparation method and reaction device of difluoroethyl acetate, and relates to the technical field of battery electrolyte additives. The preparation method comprises the following steps: in a reactor, acetate is added, and vacuum is evacuated; an excess of 2,2-difluoro-1-haloethane is added, and the temperature is raised and kept warm for reaction; after the reaction is completed, the gas phase material is introduced into a distillation tower, and the unreacted raw material 2,2-difluoro-1-haloethane is collected at the top of the tower for reuse; the tower kettle collects the crude difluoroethyl acetate; after the collection is completed, the reactor is cooled to room temperature, and the solid potassium chloride in the reactor is released. The preparation method of difluoroethyl acetate of the present invention does not use any solvent, has few by-products, and has simple reaction components, which is convenient for the purification of the target product. By reasonably controlling the amount of reaction raw materials and the reaction process, the product purity is more than 99.9%.

Description

Technical Field

[0001] The invention relates to a preparation method and a reaction device of difluoroethyl acetate, and relates to the technical field of battery electrolyte additives. Background Art

[0002] With the increasing popularity of large mobile devices (such as new energy vehicles, etc.), energy storage power stations and other portable charging devices, lithium-ion batteries are gradually occupying a dominant position in the chemical power supply market. The electrolyte is an important component of lithium-ion batteries and has an important influence on many battery properties such as output voltage, energy density, output power, life, temperature range, safety performance, etc. Fluorine has a strong electronegativity and weak polarity. Fluorinated solvents or fluorinated additives have the advantages of low melting point, high flash point, and high oxidation decomposition voltage. The wettability between fluorinated solvents and electrode materials is also good, and they have been deeply studied and widely used in the research and development of high-voltage electrolytes, high-safety electrolytes, wide temperature window electrolytes and other special functional electrolytes.

[0003] Difluoroethyl acetate is an excellent battery electrolyte additive.

[0004] Yan Caiqiao et al. (Synthesis of 2,2-difluoroethyl acetate, Chinese patent CN 113698295 A) took 2,2-difluoroethanol and acetyl chloride, and in the presence of an acid trap, carried out an acylation reaction to obtain the 2,2-difluoroethyl acetate. This method uses expensive 2,2-difluoroethanol as a raw material and obtains the target product through multiple steps of reaction.

[0005] Zhang Min et al. (Synthesis of difluoroethanol acetate, Chinese patent CN 114507134 A) cooled glacial acetic acid to below 5°C, slowly added phosphorus oxychloride, and after chlorination reaction, allowed to stand for stratification. The crude acetyl chloride obtained was directly dissolved in dichloromethane, cooled again to below 5°C, and difluoroethanol was slowly added. After the addition was complete, the acetyl chloride was acylated under the catalysis of an acid trap to obtain the difluoroethanol acetate. This method adds a preparation method for acetyl chloride to the technology of CN 113698295 A, and also uses expensive difluoroethanol and dangerous chemicals such as phosphorus oxychloride, which increases production risks.

[0006] Developing a new method for preparing difluoroethyl acetate has become an urgent problem to be solved. Summary of the invention

[0007] The invention aims to overcome the technical problems existing in the prior art, such as high raw material price, high risk in the reaction process and complicated production process, and provides a method for preparing difluoroethyl acetate.

[0008] The invention also provides a reaction device for the preparation method.

[0009] The present invention is achieved through the following measures.

[0010] The invention discloses a method for preparing difluoroethyl acetate, comprising the following steps:

[0011] (1) Add acetate to a reaction kettle, evacuate the vessel, add an excess of 2,2-difluoro-1-haloethane, raise the temperature, and keep the temperature to react;

[0012] (2) After the reaction is completed, the gas phase material is introduced into a distillation tower, and the unreacted raw material 2,2-difluoro-1-haloethane is collected at the top of the tower for recycling; the crude difluoroethyl acetate is collected at the bottom of the tower;

[0013] (3) After the collection is completed, the reactor is cooled to room temperature and the solid halide salt in the reactor is released.

[0014] In the above-mentioned method for preparing difluoroethyl acetate, preferably, in step (1), the halogen element in the 2,2-difluoro-1-haloethane is Cl, Br or I; the salt is a potassium salt; and the molar ratio of the 2,2-difluoro-1-haloethane to the acetate is 5 to 2:1.

[0015] In the above-mentioned method for preparing difluoroethyl acetate, preferably, the stirring type of the reaction kettle is a screw-belt stirring with forward and reverse rotation functions, and has a solid-liquid separation function.

[0016] In the above-mentioned method for preparing difluoroethyl acetate, preferably, in the step 1, vacuuming and nitrogen replacement are performed alternately 2-5 times, and the vacuum degree reaches -0.092~-0.099MPa;

[0017] In the step 2, after the discharge of the reactor is completed, the remaining gas phase material in the reactor is recovered by a membrane compressor;

[0018] In the step 2, the crude difluoroethyl acetate collected in the bottom of the tower is distilled twice to remove the light and heavy components to obtain high-purity difluoroethyl acetate.

[0019] In the step 3, after the collection is completed and the temperature is lowered to room temperature, the pressure in the reactor is balanced to normal pressure with nitrogen, the discharge valve of the reactor is opened, the stirring is stopped, and the stirring is reversed to release the solid potassium chloride.

[0020] In the above-mentioned method for preparing difluoroethyl acetate, preferably, in step (1), the 2,2-difluoro-1-haloethane is selected from 2,2-difluoro-1-chloroethane, and the molar ratio of 2,2-difluoro-1-chloroethane to potassium acetate is 4 to 2.5:1.

[0021] In the above-mentioned method for preparing difluoroethyl acetate, preferably, in step (1), the reaction temperature is 130-210° C., the pressure is 0.8-2.4 MPa, and the reaction time is 5-10 h.

[0022] The present invention also discloses a reaction device for the preparation method of the difluoroethyl acetate, comprising a reaction kettle, a distillation tower, a tower top condenser, a membrane compressor raw material collecting tank, and a product collecting tank; the air inlet of the distillation tower is connected to the reaction kettle, the gas phase outlet of the distillation tower is connected to the feed end of the tower top condenser, and the liquid phase material outlet of the tower top condenser is connected to the raw material collecting tank; the tower kettle discharge port of the distillation tower is connected to the product collecting tank.

[0023] The above-mentioned reaction device preferably further comprises a membrane compressor, and the membrane compressor is connected between the reaction kettle and the distillation tower.

[0024] The present invention uses relatively cheap 2,2-difluoro-1-haloethane and potassium acetate as raw materials to directly synthesize difluoroethyl acetate, and the purity of the product reaches more than 99.90% after three distillations. During the reaction process, 2,2-difluoro-1-chloroethane is both a raw material for the reaction and a solvent for the reaction, thereby avoiding the introduction of other impurities and being conducive to the preparation of a high-purity target product.

[0025] The invention uses a special reaction kettle to achieve the separation of raw materials, products and by-products (solid potassium chloride), reduces the steps of purifying potassium chloride, and achieves clean production.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention uses 2,2-difluoro-1-chloroethane and potassium acetate as raw materials to directly synthesize difluoroethyl acetate. After three distillations, the purity of the product reaches more than 99.90%.

[0028] (2) In the present invention, the molar ratio of 2,2-difluoro-1-chloroethane to potassium acetate is 2.5:1. 2,2-difluoro-1-chloroethane is both a raw material and a solvent for the reaction, thereby avoiding the introduction of other impurities and facilitating the preparation of a high-purity target product.

[0029] (3) The preparation method provided by the present invention uses a special reactor to achieve the separation of raw materials, products and by-products (solid potassium chloride), reducing the steps of purifying potassium chloride and achieving clean production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of a device for preparing difluoroethyl acetate;

[0031] Among them: 1 is a reaction kettle, 2 is a distillation tower, 3 is a tower top condenser, 4 is a membrane compressor, 5 is a raw material collecting tank, and 6 is a product collecting tank. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further explained and illustrated by means of specific embodiments below.

[0033] Example 1

[0034] like Figure 1 As shown, the reaction device provided by the present invention includes a reaction kettle 1, a distillation tower 2, a tower top condenser 3, a membrane compressor 4, a raw material collecting tank 5, and a product collecting tank 6.

[0035] The reactor 1 has a screw-belt stirring type with forward and reverse rotation functions and has a solid-liquid separation function.

[0036] The distillation tower (2) is connected to the reactor (1); the gas phase outlet of the distillation tower (2) is connected to the feed end of the tower top condenser (3); the liquid phase material outlet of the tower top condenser (3) is connected to the 2,2-difluoro-1-chloroethane raw material collecting tank (5); the tower bottom discharge of the distillation tower (2) is connected to the difluoroethyl acetate product collecting tank (6); the material inlet of the diaphragm compressor (4) is connected to the gas phase outlet of the special reactor (1); and the material outlet of the diaphragm compressor (4) is connected to the gas phase inlet of the distillation tower (2).

[0037] In the 1m³ reactor 1, 200kg (2.0kmol) of potassium acetate with a content of 98% was added, and the vacuum was evacuated and replaced with nitrogen for 3 times, and the vacuum was evacuated to -0.098MPa again; 507.06kg (5.0kmol) of 2,2-difluoro-1-chloroethane with a content of 99.1% was added to the reactor 1, and the temperature was raised to 180°C, and the pressure was about 1.65MPa. After keeping warm for 6 hours, the gas phase material in the reactor was slowly decompressed twice and continuously and uniformly introduced into the distillation tower 2. After the tower bottom liquid level was normal, the distillation tower 2 was opened, and 2,2-difluoro-1-chloroethane was extracted from the top of the tower and collected in the 2,2-difluoro-1-chloroethane raw material collection tank 5. The tower bottom material was continuously collected into the difluoroethyl acetate product collection tank 6 according to the distillation tower bottom liquid level.

[0038] After the pressure of the reactor drops to normal pressure, start the membrane compressor 4, and recycle the remaining gaseous materials in the reactor into the distillation tower. After the pressure of the reactor drops to -0.06MPa, stop the membrane compressor 4. After the temperature of the reactor drops to room temperature, balance the pressure in the reactor to normal pressure with nitrogen, open the reactor discharge valve, stop stirring, and reverse the stirring to release the by-product potassium chloride in the reactor.

[0039] The crude difluoroethyl acetate product was further distilled in a light removal distillation tower and a heavy removal distillation tower to obtain 235 kg of difluoroethyl acetate product with a purity of 99.92% and a yield of 94.68%.

[0040] Example 2

[0041] Using the same reaction apparatus as in Example 1, the following preparation was performed:

[0042] In the 1m³ reactor 1, 100kg (1.0kmol) of potassium acetate with a content of 98% was added, and the vacuum was evacuated and replaced with nitrogen for 3 times, and the vacuum was evacuated to -0.095MPa again; 405.65kg (4kmol) of 2,2-difluoro-1-chloroethane with a content of 99.1% was added to the reactor 1, and the temperature was raised to 180°C and the pressure was 1.58MPa. After keeping warm for 5 hours, the gas phase material in the reactor was slowly decompressed twice and continuously and uniformly introduced into the distillation tower 2. After the tower bottom liquid level was normal, the distillation tower 2 was opened, and 2,2-difluoro-1-chloroethane was extracted from the top of the tower and collected in the 2,2-difluoro-1-chloroethane raw material collection tank 5. The tower bottom material was continuously collected into the difluoroethyl acetate product collection tank 6 according to the distillation tower bottom liquid level.

[0043] After the pressure of the reactor drops to normal pressure, start the membrane compressor 4, and recycle the remaining gaseous materials in the reactor into the distillation tower. After the pressure of the reactor drops to -0.06MPa, stop the membrane compressor 4. After the temperature of the reactor drops to room temperature, balance the pressure in the reactor to normal pressure with nitrogen, open the reactor discharge valve, stop stirring, and reverse the stirring to release the by-product potassium chloride in the reactor.

[0044] The crude difluoroethyl acetate product was further distilled in a light removal distillation tower and a heavy removal distillation tower to obtain 118.35 kg of difluoroethyl acetate product with a purity of 99.95% and a yield of 95.39%.

[0045] Example 3

[0046] Using the same reaction apparatus as in Example 1, the following preparation was performed:

[0047] In the 1m³ reactor 1, 100kg (1.0kmol) of potassium acetate with a content of 98% was added, and the vacuum was evacuated and replaced with nitrogen for 3 times, and the vacuum was evacuated to -0.096MPa again; 304.23kg (3kmol) of 2,2-difluoro-1-chloroethane with a content of 99.1% was added to the reactor 1, and the temperature was raised to 210°C and the pressure was 2.4MPa. After keeping warm for 5 hours, the gas phase material in the reactor was slowly decompressed twice and continuously and uniformly introduced into the distillation tower 2. After the tower bottom liquid level was normal, the distillation tower 2 was opened, and 2,2-difluoro-1-chloroethane was extracted from the top of the tower and collected in the 2,2-difluoro-1-chloroethane raw material collection tank 5. The tower bottom material was continuously collected into the difluoroethyl acetate product collection tank 6 according to the distillation tower bottom liquid level.

[0048] After the pressure of the reactor drops to normal pressure, start the membrane compressor 4, and recycle the remaining gaseous materials in the reactor into the distillation tower. After the pressure of the reactor drops to -0.06MPa, stop the membrane compressor 4. After the temperature of the reactor drops to room temperature, balance the pressure in the reactor to normal pressure with nitrogen, open the reactor discharge valve, stop stirring, and reverse the stirring to release the by-product potassium chloride in the reactor.

[0049] The crude difluoroethyl acetate product was further distilled in a light removal distillation tower and a heavy removal distillation tower to obtain 111.27 kg of difluoroethyl acetate product with a purity of 99.90% and a yield of 89.64%.

Claims

1. A method for preparing difluoroethyl acetate, characterized in that, The following steps are involved: (1) Add acetate to a reaction kettle, evacuate the vessel, add an excess of 2,2-difluoro-1-haloethane, raise the temperature, and keep the temperature to react; the molar ratio of 2,2-difluoro-1-haloethane to acetate is 5 to 2:1; the reaction temperature is 130 to 210° C., the pressure is 0.8 to 2.4 MPa, and the reaction time is 5 to 10 hours; (2) After the reaction is completed, the gas phase material is introduced into a distillation tower, and the unreacted raw material 2,2-difluoro-1-haloethane is collected at the top of the tower for recycling; the crude difluoroethyl acetate is collected at the bottom of the tower; (3) After the collection is completed, the reactor is cooled to room temperature and the solid halide salt in the reactor is released; The reaction device used in the preparation method comprises a reaction kettle (1), a distillation tower (2), a tower top condenser (3), a membrane compressor (4), a raw material collecting tank (5), and a product collecting tank (6); the air inlet of the distillation tower (2) is connected to the reaction kettle (1), the gas phase outlet of the distillation tower (2) is connected to the feed end of the tower top condenser (3), and the liquid phase material outlet of the tower top condenser (3) is connected to the raw material collecting tank (5); and the tower kettle discharge port of the distillation tower (2) is connected to the product collecting tank (6).

2. The method for preparing difluoroethyl acetate according to claim 1, wherein In step (1), the halogen element in the 2,2-difluoro-1-haloethane is Cl, Br or I; and the salt is a potassium salt.

3. The method for preparing difluoroethyl acetate according to claim 1, wherein The stirring type of the reaction kettle is a screw belt stirring with forward and reverse rotation functions, and has a solid-liquid separation function.

4. The method for preparing difluoroethyl acetate according to claim 1, wherein In the step (1), vacuuming and nitrogen replacement are performed alternately 2-5 times, and the vacuum degree reaches -0.092~-0.099MPa; In the step (2), after the discharge of the reactor is completed, the remaining gas phase material in the reactor is recovered by a membrane compressor; In the step (2), the crude difluoroethyl acetate collected in the bottom of the tower is distilled twice to remove the light and heavy components to obtain high-purity difluoroethyl acetate; In the step (3), after the collection is completed and the temperature is lowered to room temperature, the pressure in the reactor is balanced to normal pressure with nitrogen, the discharge valve of the reactor is opened, the stirring is stopped, and the stirring is reversed to release the solid potassium chloride.

5. The method for preparing difluoroethyl acetate according to claim 2, wherein In step (1), the 2,2-difluoro-1-haloethane is selected from 2,2-difluoro-1-chloroethane, and the molar ratio of 2,2-difluoro-1-chloroethane to potassium acetate is 4 to 2.5:

1.

6. The method for preparing difluoroethyl acetate according to claim 1, characterized in that, The reaction device also includes a membrane compressor (4), which is connected between the reaction kettle (1) and the distillation tower (2).

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