Preparation method and preparation device of ethyl difluoroacetate

Abstract

The invention provides a preparation method and a preparation device of ethyl difluoroacetate, and the preparation method comprises the following steps: S1, mixing and stirring ethyl dichloroacetate and potassium bifluoride in a reaction container, heating, and reacting; s2, generating a solid-phase material, a liquid-phase material and a gas-phase material after the reaction is completed, and separating the solid-phase material from the liquid-phase material; s3, distilling and purifying the separated liquid-phase material to obtain the ethyl difluoroacetate. Therefore, an existing ethyl difluoroacetate production scheme is replaced, in the whole preparation process, reaction conditions are mild, the requirement for equipment is low, operation is easy, cost is low, large-scale production is easy to achieve, and the obtained ethyl difluoroacetate is high in purity.

Description

Technical Field

[0001] The invention relates to the field of preparation of ethyl difluoroacetate, and in particular to a method for preparing ethyl difluoroacetate and a preparation device thereof. Background Art

[0002] Ethyl difluoroacetate is an important organic intermediate, widely used in medicine, pesticide and organic synthesis.

[0003] At present, the method for preparing ethyl difluoroacetate mainly contains the following several:

[0004] Method 1, using tetrafluoroethylene as raw material: This method involves the addition of tetrafluoroethylene to methanol, followed by catalytic cracking to obtain difluoroacetyl fluoride, which is then esterified with ethanol to obtain ethyl difluoroacetate. Although this method has a high yield, tetrafluoroethylene is not easy to obtain, has high requirements for equipment, and has high risks in the production process.

[0005] Method 2, using difluoroethylene as raw material: difluoroethylene is chlorinated or brominated, and then catalyzed by fuming sulfuric acid, mercuric sulfate, or mercurous sulfate to obtain acyl chloride, which is then reacted with ethanol, and finally dehalogenated with zinc powder to obtain ethyl difluoroacetate. This method has the problems of low yield, severe equipment corrosion, large amount of three wastes, and high cost.

[0006] Method 3: Using acyl compounds as substrates, reacting with potassium fluoride, and preparing difluoroacetic acid through hydrolysis and distillation. In this process, when the acyl compound is difluoroacetyl chloride or difluoroacetyl fluoride, the selectivity of the reaction is poor; in addition, fluorides such as hydrogen fluoride are easily produced during the reaction, resulting in high risk of the reaction and impact on the environment.

[0007] In summary, among the numerous preparation methods of ethyl difluoroacetate, many preparation methods have problems such as harsh reaction conditions, high requirements on equipment performance, and difficulty in obtaining raw materials. Therefore, it is of great significance to develop a preparation method and system with mild reaction conditions, simple operation, and low cost.

[0008] The purpose of the present invention is to design a method and a device for preparing ethyl difluoroacetate in view of the problems existing in the prior art. Summary of the invention

[0009] The invention provides a method for preparing ethyl difluoroacetate and a preparation device thereof, which can effectively solve the above problems.

[0010] The present invention is achieved in that:

[0011] A method for preparing ethyl difluoroacetate comprises the following steps:

[0012] S1, mixing ethyl dichloroacetate and potassium bifluoride in a reaction container, stirring and heating to carry out a reaction;

[0013] S2, after the reaction is completed, solid phase material, liquid phase material and gas phase material are generated, and the solid phase material and the liquid phase material are separated;

[0014] S3, distilling and purifying the separated liquid phase material to obtain ethyl difluoroacetate.

[0015] Furthermore, in step S1, the heating temperature of the reaction container is 100° C.-130° C., and the reaction time of ethyl dichloroacetate and potassium bifluoride is 2 h-6 h.

[0016] Furthermore, in step S1, the molar ratio of potassium bifluoride to ethyl dichloroacetate is 2.5:1.

[0017] Further, the solid phase material includes potassium fluoride and unreacted potassium bifluoride, the liquid phase material includes ethyl difluoroacetate and unreacted ethyl dichloroacetate, and the gas phase material includes hydrogen chloride gas and hydrogen fluoride gas;

[0018] After step S3, the following steps are also included:

[0019] S4, returning the separated solid phase material to the reaction container, introducing hydrogen fluoride gas from the outside to react with potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride.

[0020] Furthermore, after step S4, the following steps are further included:

[0021] S5, after the gas phase material is introduced into the aqueous solution to absorb the hydrogen chloride, the remaining hydrogen fluoride gas is combined with the external hydrogen fluoride gas and introduced into the reaction container to react with the potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride.

[0022] Further, step S3 specifically comprises: inputting the separated liquid phase material into a distillation tower for distillation and purification to obtain ethyl difluoroacetate; the ethyl difluoroacetate and unreacted ethyl dichloroacetate are distilled to the top and bottom of the distillation tower respectively, the bottom temperature of the distillation tower is 110°C-150°C, the top temperature is 90°C-110°C, and the reflux ratio is 4-10;

[0023] After step S5, the following steps are also included:

[0024] S6, returning the ethyl dichloroacetate solution at the bottom of the distillation tower to the reaction container.

[0025] The preparation device of the method for preparing ethyl difluoroacetate as described above comprises:

[0026] A reaction container, comprising a reaction chamber for mixed reaction of ethyl dichloroacetate and potassium bifluoride, and a stirring member driven by a rotary driving device to rotate and stir in the reaction chamber;

[0027] A separation structure, used for separating the solid phase material and the liquid phase material generated by the mixed reaction of ethyl dichloroacetate and potassium bifluoride;

[0028] The distillation tower is used to distill and purify the liquid phase material separated by the separation structure to obtain ethyl difluoroacetate.

[0029] Furthermore, the reaction container also includes an adjusting chamber separated from the bottom of the reaction chamber, an opening is passed through between the reaction chamber and the adjusting chamber and a flexible deformable part is sealed and embedded therein, an adjusting drive device with a telescopic end connected to the middle part of the bottom of the deformable part is provided in the adjusting chamber, the separation structure includes the deformable part and the adjusting drive device, the stirring parts are provided in a plurality and are circumferentially spaced apart and distributed between the deformable part and the inner wall of the reaction chamber, and the discharge port of the reaction container corresponds to the inner bottom of the reaction chamber; when the telescopic end of the adjusting drive device is pushed up, the upper arch of the deformable part protrudes above the bottom wall of the reaction chamber to form a guiding protrusion, and when the telescopic end of the adjusting drive device is pulled down, the lower concave protrusion of the deformable part protrudes below the bottom wall of the reaction chamber to form a collecting groove.

[0030] Furthermore, a plurality of guide grooves are provided on the top of the deformable member, which are distributed circumferentially at intervals and extend spirally from the center to the periphery, and the spiral direction of the guide grooves is consistent with the rotational stirring direction of the stirring member; when the deformable member is arched upward to form a guide protrusion, a plurality of the guide grooves are opened and used for guiding, and when the deformable member is concave downward to form a collecting groove, a plurality of the guide grooves are squeezed and closed.

[0031] The beneficial effects of the present invention are:

[0032] 1. Ethyl difluoroacetate is effectively synthesized by using ethyl dichloroacetate and potassium bifluoride as raw materials. In the reaction process of the two, potassium bifluoride is used as both a reaction raw material and a catalyst, and ethyl difluoroacetate is purified in the product through a distillation process, thereby replacing the existing production scheme of ethyl difluoroacetate. In the whole preparation process, the reaction conditions are mild, the equipment requirements are low, the operation is simple, the cost is low, and large-scale production is easy to achieve, and the obtained ethyl difluoroacetate has high purity.

[0033] 2. Through the reaction treatment of hydrogen fluoride gas and solid phase materials, the product potassium fluoride is converted back to potassium bifluoride and then continues to be used as a reaction raw material for preparing ethyl difluoroacetate, so as to realize the reuse of the product potassium fluoride and unreacted potassium bifluoride. Under the condition of the same volume of potassium bifluoride raw material, the volume of ethyl difluoroacetate product that can be generated is increased, and the preparation rate of ethyl difluoroacetate is improved.

[0034] 3. After the gas phase material is absorbed by the aqueous solution, the remaining hydrogen fluoride gas is used to assist the external hydrogen fluoride gas to convert the returned solid phase material back into potassium hydrogen fluoride, so as to realize the reuse of the product hydrogen fluoride gas, which can reduce the external hydrogen fluoride gas required in step S4 and reduce the reuse cost of the solid phase material. At the same time, the reuse of hydrogen fluoride can avoid the impact of hydrogen fluoride discharged into the air on the environment, and can also save the environmental protection treatment cost of hydrogen fluoride.

[0035] 4. The liquid phase material is distilled by a distillation tower to accurately separate the product ethyl difluoroacetate and the unreacted ethyl dichloroacetate, so that the ethyl difluoroacetate can be returned to the reaction container to participate in the reaction as a solvent again, so as to realize the reuse of the unreacted ethyl dichloroacetate. Under the condition of the same volume of ethyl dichloroacetate raw material, the volume of ethyl difluoroacetate product that can be generated is increased, and the preparation rate of ethyl difluoroacetate is improved.

[0036] 5. The stirring element is used to stir and the concave collecting groove is used to lower the horizontal height of the solid-phase material after it is collected, so that the solid-phase material and the liquid-phase material can be directly separated in the reaction chamber, and the operation of returning the solid-phase material after being output from the reaction chamber is reduced to avoid the loss of the solid-phase material. At the same time, the solid-liquid separation efficiency is accelerated, the production steps are simplified, and the preparation efficiency of ethyl difluoroacetate is improved.

[0037] 6. When the plurality of stirring members rotate circumferentially for stirring, the ethyl dichloroacetate solvent in the reaction chamber is rotated by force to form a centripetal force. The crystalline powdery potassium bifluoride is gathered toward the center of the reaction chamber by the centripetal force and then sinks to the guide protrusion of the deformable member, and is guided to diffuse outwardly between the deformable member and the inner wall of the reaction chamber, and then is stirred and dispersed by the stirring member and then gathered again by the centripetal force. In the reaction process, the potassium bifluoride powder is stirred-sunk-expanded-dispersed in a cycle in the reaction chamber by the stirring of the stirring member and the guiding of the guide protrusion, so as to improve the stirring effect and reaction efficiency, and ensure the reaction efficiency of potassium bifluoride and ethyl dichloroacetate under the premise that the solid phase material and the liquid phase material can be directly separated in the reaction chamber.

[0038] 7. When the plurality of stirring members rotate circumferentially for stirring, the ethyl dichloroacetate solvent in the reaction chamber is rotated by force to form a centripetal force. When the crystalline powdery potassium bifluoride is gathered toward the center of the reaction chamber by the centripetal force and then sinks to the guide protrusion of the deformation member, the potassium bifluoride that has been gathered and sunk is flushed outward by the spiral guidance of the ethyl dichloroacetate solvent by the plurality of guiding fine grooves, thereby increasing the rate at which the potassium bifluoride expands outward between the deformation member and the inner wall of the reaction chamber, thereby increasing the progress of the process of its expansion-dispersion, and reducing the probability of the potassium bifluoride staying on the guide protrusion, thereby ensuring the stability and efficiency of the cyclic motion of the potassium bifluoride powder in the reaction chamber of gathering-sinking-expanding-dispersion, further improving the stirring effect and reaction efficiency, that is, further ensuring the reaction efficiency of potassium bifluoride and ethyl dichloroacetate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The figure is a flow chart of the steps of the preparation method of Example 1.

[0040] Figure 2 The figure is a flow chart of the steps of the preparation method of Example 1.

[0041] Figure 3 The figure is a flow chart of the steps of the preparation method of Example 2.

[0042] Figure 4 It is a schematic diagram of the cross-sectional structure when the deformable member of the preparation device of Example 2 forms a guide protrusion.

[0043] Figure 5 It is a schematic diagram of the cross-sectional structure when the deformable part of the preparation device of Example 2 forms a collecting groove.

[0044] Figure 6 This is a schematic diagram of the structure of the deformation member of the preparation device of Example 2. DETAILED DESCRIPTION

[0045] Embodiment 1

[0046] Reference Figure 1-2 As shown, a method for preparing ethyl difluoroacetate and a preparation device thereof, comprising:

[0047] S1, mixing ethyl dichloroacetate and potassium bifluoride in a reaction vessel 1, stirring and heating to react; specifically, the heating temperature of the reaction vessel 1 is 100° C.-130° C., the reaction time of ethyl dichloroacetate and potassium bifluoride is 2h-6h, preferably, the heating temperature is 120° C., the reaction time is 2h, and the molar ratio of potassium bifluoride to ethyl dichloroacetate is 2.5:1;

[0048] S2, after the reaction is completed, a solid phase material, a liquid phase material and a gas phase material are generated, the solid phase material includes potassium fluoride and unreacted potassium bifluoride, the liquid phase material includes ethyl difluoroacetate and unreacted ethyl dichloroacetate, and the gas phase material includes hydrogen chloride gas and hydrogen fluoride gas, and the solid phase material and the liquid phase material are separated; specifically, in this embodiment, the solid phase material and the liquid phase material are separated after filtering by a filtering device, such as filter paper filtering, screen filtering, etc.;

[0049] S3, distill and purify the liquid phase material obtained by separation to obtain ethyl difluoroacetate. Specifically, the liquid phase material obtained by separation is input into a distillation tower for distillation and purification, and the ethyl difluoroacetate and unreacted ethyl dichloroacetate are distilled to the top and bottom of the distillation tower respectively, and the bottom temperature of the distillation tower is 110°C-150°C, the top temperature is 90°C-110°C, and the reflux ratio is 4-10. Preferably, in this embodiment, the bottom temperature is 120°C, the top temperature is 97°C, and the reflux ratio is 10.

[0050] The chemical reaction formula for the reaction of ethyl dichloroacetate and potassium bifluoride to produce ethyl difluoroacetate is as follows:

[0051]

[0052] The preparation method effectively synthesizes ethyl difluoroacetate by using ethyl dichloroacetate and potassium bifluoride as raw materials. In the reaction process of the two, potassium bifluoride serves as both a reaction raw material and a catalyst, and ethyl difluoroacetate is purified in the product through a distillation process, thereby replacing the existing production scheme of ethyl difluoroacetate. In the whole preparation process, the reaction conditions are mild, the equipment requirements are low, the operation is simple, the cost is low, and large-scale production is easy to achieve, and the obtained ethyl difluoroacetate has high purity.

[0053] In order to improve the utilization rate of the reaction product of ethyl dichloroacetate and potassium bifluoride, step S3 further comprises:

[0054] S4, returning the separated solid-phase material to the reaction vessel 1, introducing hydrogen fluoride gas from the outside to react with potassium fluoride in the returned solid-phase material to generate potassium bifluoride. Specifically, the reaction vessel 1 can be pressurized when the hydrogen fluoride gas reacts with potassium fluoride. Thus, through the reaction treatment of hydrogen fluoride gas with the solid-phase material, the product potassium fluoride is converted back to potassium bifluoride and continues to be used as a reaction raw material for preparing ethyl difluoroacetate, so as to achieve the reuse of the product potassium fluoride and unreacted potassium bifluoride, and under the condition of the same volume of potassium bifluoride raw material, the volume of ethyl difluoroacetate product that can be generated is increased, and the preparation rate of ethyl difluoroacetate is increased.

[0055] In order to further improve the utilization rate of the reaction product of ethyl dichloroacetate and potassium bifluoride, step S4 further includes:

[0056] S5, after the gas phase material is introduced into the aqueous solution to absorb the hydrogen chloride, the remaining hydrogen fluoride gas is merged with the external hydrogen fluoride gas and introduced into the reaction vessel 1 to react with the potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride. Thus, after the gas phase material is absorbed by the aqueous solution, the remaining hydrogen fluoride gas is used to assist the external hydrogen fluoride gas to convert the returned solid phase material back into potassium hydrogen fluoride, so as to realize the reuse of the product hydrogen fluoride gas, which can reduce the external hydrogen fluoride gas required in step S4 and reduce the reuse cost of the solid phase material. At the same time, the reuse of hydrogen fluoride can avoid the impact of hydrogen fluoride discharged into the air on the environment, and can also save the environmental protection treatment cost of hydrogen fluoride.

[0057] In order to further improve the utilization rate of the reaction product of ethyl dichloroacetate and potassium bifluoride, step S5 further includes:

[0058] S6, returning the ethyl dichloroacetate solution at the bottom of the distillation tower to the reaction vessel 1. Thus, the liquid phase material is distilled by the distillation tower to accurately separate the product ethyl difluoroacetate and the unreacted ethyl dichloroacetate, so that the ethyl difluoroacetate can be returned to the reaction vessel 1 to participate in the reaction again as a solvent, so as to achieve the reuse of the unreacted ethyl dichloroacetate, increase the volume of the ethyl difluoroacetate product that can be generated under the condition of the same volume of the ethyl dichloroacetate raw material, and improve the preparation rate of ethyl difluoroacetate.

[0059] The preparation device of the method for preparing ethyl difluoroacetate as described above comprises:

[0060] The reaction vessel 1 comprises a reaction chamber 11 for providing a mixed reaction of ethyl dichloroacetate and potassium bifluoride, and a stirring member 12 driven by a rotary driving device 13 to rotate and stir in the reaction chamber 11; specifically, the reaction vessel 1 is a reactor, and the rotary driving device 13 is a rotary motor installed in the middle of the top of the reactor;

[0061] A separation structure, used to separate the solid phase material and the liquid phase material generated by the mixed reaction of the ethyl dichloroacetate and potassium bifluoride; specifically, in this embodiment, the separation structure can be a filter structure such as a filter paper filter structure and a screen filter structure;

[0062] The distillation tower is used to distill and purify the liquid phase material separated by the separation structure to obtain ethyl difluoroacetate. Specifically, in this embodiment, in order to improve the extraction purity of ethyl difluoroacetate, the distillation tower is further improved into a rectification tower.

[0063] The preparation steps of ethyl difluoroacetate in this embodiment:

[0064] S1, ethyl dichloroacetate and potassium bifluoride are mixed, stirred and heated in a reaction vessel 1 to carry out a reaction;

[0065] S2, after the reaction is completed, solid phase material, liquid phase material and gas phase material are generated;

[0066] S3, inputting the separated liquid phase material into a distillation tower for distillation and purification to obtain ethyl difluoroacetate;

[0067] S4, returning the separated solid phase material to the reaction vessel 1, introducing hydrogen fluoride gas from the outside to react with potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride;

[0068] S5, after the gas phase material is introduced into the aqueous solution to absorb the hydrogen chloride, the remaining hydrogen fluoride gas is merged with the external hydrogen fluoride gas and introduced into the reaction container 1 to react with the potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride;

[0069] S6, returning the ethyl dichloroacetate solution at the bottom of the distillation tower to the reaction vessel 1.

[0070] Specifically, 78.5 g of ethyl dichloroacetate and 97.6 g of potassium bifluoride were added to the reaction kettle, stirring was started, the reaction temperature was maintained at 120° C., and the reaction was carried out for 2 hours. After the reaction was completed, the filtrate was filtered, and the filtrate was distilled and purified. The obtained distillate was taken for gas chromatography detection, and the purity of ethyl difluoroacetate was measured to be 94%, and the conversion rate was calculated to be 85%.

[0071] Embodiment 2

[0072] The difference between this embodiment and the first embodiment is that:

[0073] Add 785g of ethyl dichloroacetate and 976g of potassium bifluoride to the reactor, start stirring, maintain the reaction temperature at 120°C, and react for 2h. After the reaction is completed, filter, distill and purify the filtrate, take the obtained distillate for gas chromatography detection, and the purity of ethyl difluoroacetate is measured to be 96%, and the conversion rate is calculated to be 83%.

[0074] It can be seen that after increasing the grams of ethyl dichloroacetate and potassium bifluoride, the purity and conversion rate of the generated ethyl difluoroacetate remain stable. Therefore, the preparation method of the present application has the advantages of high purity and conversion rate, stable purity and conversion rate, mild reaction conditions, and simple operation, and is suitable for industrial production.

[0075] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0076] Embodiment 3

[0077] In order to improve the conversion rate of preparing ethyl difluoroacetate by the reaction of ethyl dichloroacetate and potassium bifluoride, the difference between this embodiment and embodiment 1 is that:

[0078] Add 78.5g of ethyl dichloroacetate, 97.6g of potassium bifluoride and 10g of TEBA to the reactor, start stirring, maintain the reaction temperature at 120°C, and react for 2h. After the reaction is completed, filter, distill and purify the filtrate, take the obtained distillate for gas chromatography detection, and the purity of ethyl difluoroacetate is measured to be 95%, and the conversion rate is calculated to be 98%.

[0079] Among them, TEBA is benzyltriethylammonium chloride, an organic compound and also a phase transfer catalyst, with a molecular formula of C13H22ClN. The pure product is white crystals or powder. It can be seen that on the basis of ethyl dichloroacetate and potassium bifluoride as raw materials and unchanged reaction conditions, adding TEBA as a phase transfer catalyst component can greatly improve the conversion rate of the preparation method of ethyl difluoroacetate.

[0080] Therefore, step S1 in this embodiment specifically includes: mixing ethyl dichloroacetate, potassium bifluoride and TEBA in a reaction container 1, stirring and heating to react.

[0081] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0082] Embodiment 4

[0083] In order to improve the conversion rate of preparing ethyl difluoroacetate by the reaction of ethyl dichloroacetate and potassium bifluoride, the difference between this embodiment and embodiment 1 is that:

[0084] Add 78.5g of ethyl dichloroacetate, 97.6g of potassium hydrogen fluoride and 10g of tetrabutylammonium bromide to the reactor, start stirring, maintain the reaction temperature at 120°C, and react for 2h. After the reaction is completed, filter, distill and purify the filtrate, take the obtained distillate for gas chromatography detection, and the purity of ethyl difluoroacetate is measured to be 94%, and the conversion rate is calculated to be 93%.

[0085] Among them, tetrabutylammonium bromide is an organic salt and also a phase transfer catalyst with a molecular formula of C 16 H 36 BrN, pure product is white crystals or powder. It can be seen that on the basis of ethyl dichloroacetate and potassium bifluoride as raw materials and unchanged reaction conditions, adding tetrabutylammonium bromide as a phase transfer catalyst component can greatly improve the conversion rate of the preparation method of ethyl difluoroacetate.

[0086] Therefore, step S1 in this embodiment specifically includes: mixing ethyl dichloroacetate, potassium hydrogen fluoride and tetrabutylammonium bromide in a reaction container 1, stirring and heating to carry out a reaction.

[0087] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0088] Embodiment 5

[0089] In order to improve the conversion rate of preparing ethyl difluoroacetate by the reaction of ethyl dichloroacetate and potassium bifluoride, the difference between this embodiment and embodiment 1 is that:

[0090] Add 78.5g of ethyl dichloroacetate, 97.6g of potassium bifluoride and 10g of chain polyethylene glycol to the reaction kettle, start stirring, maintain the reaction temperature at 120°C, and react for 2h. After the reaction is completed, filter, distill and purify the filtrate, take the obtained distillate for gas chromatography detection, and the purity of ethyl difluoroacetate is measured to be 94%, and the conversion rate is calculated to be 90%.

[0091] Among them, chain polyethylene glycol is a high molecular polymer and also a phase transfer catalyst, and its chemical formula is HO(CH2CH2O)nH. It can be seen that on the basis of ethyl dichloroacetate and potassium bifluoride as raw materials and unchanged reaction conditions, adding chain polyethylene glycol as a phase transfer catalyst component can greatly improve the conversion rate of the preparation method of ethyl difluoroacetate.

[0092] Therefore, step S1 in this embodiment specifically includes: mixing ethyl dichloroacetate, potassium bifluoride and chain polyethylene glycol in a reaction container 1, stirring and heating to react.

[0093] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0094] Embodiment 6

[0095] Since the process of taking out the reaction product and returning it will cause material loss, external separation will cause potassium fluoride to be hygroscopic, and the steps of taking out and separating are relatively cumbersome, therefore, reference Figure 3-6 The difference between this embodiment and the first embodiment is that:

[0096] In order to realize direct separation of solid-phase materials and liquid-phase materials in the reaction vessel 1, the reaction vessel 1 also includes an adjusting chamber 14 separated from the bottom of the reaction chamber 11, an opening is penetrated between the reaction chamber 11 and the adjusting chamber 14 and a flexible deformable member 2 is sealed and embedded, an adjusting driving device 3 whose telescopic end is connected to the bottom middle part of the deformable member 2 is provided in the adjusting chamber 14, the separation structure includes the deformable member 2 and the adjusting driving device 3, the stirring members 12 are provided in a plurality and are circumferentially spaced and distributed between the deformable member 2 and the inner wall of the reaction chamber 11, and the discharge port 15 of the reaction vessel 1 corresponds to the inner bottom of the reaction chamber 11; when the telescopic end of the adjusting driving device 3 is pushed up, the upper arch of the deformable member 2 protrudes above the bottom wall of the reaction chamber 11 to form a guide protrusion 21, and when the telescopic end of the adjusting driving device 3 is pulled down, the lower concave and convex of the deformable member 2 protrudes below the bottom wall of the reaction chamber 11 to form a collecting groove 22. Specifically, the adjusting drive device 3 can be set as a telescopic motor, the upper end of the telescopic end of the adjusting drive device 3 is set as a flexible part 31 flexibly connected to the bottom of the deformable member 2, the rotating shaft of the rotating drive device 13 is connected to several stirring members 12 through a linkage frame 131, and the deformable member 2 is made of a high-temperature resistant flexible material, such as high-temperature resistant rubber, silicone, etc.

[0097] The separation of the solid-phase material and the liquid-phase material in step S2 specifically includes: after controlling the adjusting driving device 3 to pull down the deformable member 2 so that the concave and convex part is below the bottom wall of the reaction chamber 11 to form a collecting groove 22, closing the rotating driving device 13 to stop the stirring of the plurality of stirring members 12, so that the liquid-phase material in the reaction chamber 11 continues to rotate under the action of inertia to form a centripetal force and gradually decelerates, and the solid-phase material in the reaction chamber 11 is collected at the center of the reaction chamber 11 under the action of the centripetal force and gradually sinks and is collected in the collecting groove 22. After the reaction container 1 is left to stand for a certain period of time, since the density of ethyl difluoroacetate is less than ethyl dichloroacetate, less than potassium hydrogen fluoride, the density of ethyl difluoroacetate, ethyl dichloroacetate, potassium hydrogen fluoride and potassium fluoride are sequentially distributed up and down in the reaction chamber 11, and the ethyl difluoroacetate and ethyl dichloroacetate in the reaction chamber 11 are discharged through the discharge port 15.

[0098] Therefore, the stirring of the stirring member 12 and the depression of the collecting groove 22 can reduce the horizontal height of the solid-phase material after it is collected, so that the solid-phase material and the liquid-phase material can be directly separated in the reaction chamber 11, and the operation of returning the solid-phase material after being output from the reaction chamber 11 can be reduced to avoid the loss of the solid-phase material. At the same time, the solid-liquid separation efficiency is accelerated, the production steps are simplified, and the preparation efficiency of ethyl difluoroacetate is improved.

[0099] On this basis, since potassium bifluoride is always gathered in the center of the reaction chamber 11 by the centripetal force when the stirring member 12 is stirring, the contact area between potassium bifluoride and ethyl dichloroacetate is reduced, resulting in a decrease in reaction efficiency. Therefore, in order to ensure the reaction efficiency of potassium bifluoride and ethyl dichloroacetate under the premise that the solid phase material and the liquid phase material can be directly separated in the reaction chamber 11:

[0100] Step S1 specifically includes: after controlling and adjusting the driving device 3 to push up the deformable member 2 to protrude above the bottom wall of the reaction chamber 11 to form a guide protrusion 21, ethyl dichloroacetate and potassium hydrogen fluoride are mixed, stirred and heated in the reaction container 1 to react.

[0101] Therefore, when the plurality of stirring members 12 rotate circumferentially for stirring, the ethyl dichloroacetate solvent in the reaction chamber 11 is rotated by force to form a centripetal force, and the crystalline powdery potassium bifluoride is gathered toward the center of the reaction chamber 11 by the centripetal force and then sinks to the guide protrusion 21 of the deformation member 2, and is guided to diffuse outwardly between the deformation member 2 and the inner wall of the reaction chamber 11, and then is stirred and dispersed by the stirring member 12 and gathered again by the centripetal force, so that in the reaction process, the potassium bifluoride powder is stirred-sunk-expanded-dispersed in the reaction chamber 11 by the stirring of the stirring member 12 and guided by the guide protrusion 21 to achieve a cyclic movement of gathering-sinking-expanding-being-dispersed in the reaction chamber 11, so as to improve the stirring effect and reaction efficiency, and ensure the reaction efficiency of potassium bifluoride and ethyl dichloroacetate under the premise that the solid phase material and the liquid phase material can be directly separated in the reaction chamber 11.

[0102] In order to further ensure the reaction efficiency of potassium bifluoride and ethyl dichloroacetate, a plurality of guide grooves 23 are provided on the top of the deformable member 2, which are distributed at circumferential intervals and spirally extend from the center to the periphery, and the spiral direction of the guide grooves 23 is consistent with the rotation and stirring direction of the stirring member 12; when the deformable member 2 is arched upward to form the guide protrusion 21, a plurality of the guide grooves 23 are opened and used for guiding, and when the deformable member 2 is concave to form the collecting groove 22, a plurality of the guide grooves 23 are squeezed and closed.

[0103] Step S1 further specifically includes: after controlling and adjusting the driving device 3 to push the deformable member 2 upward to protrude above the bottom wall of the reaction chamber 11 to form a guide protrusion 21, a plurality of the guide grooves 23 are opened and used for guide flow, and ethyl dichloroacetate and potassium bifluoride are mixed, stirred and heated in the reaction container 1 to react.

[0104] Therefore, when the plurality of stirring members 12 rotates circumferentially for stirring, the ethyl dichloroacetate solvent in the reaction chamber 11 is rotated by force to form a centripetal force. When the crystalline powdery potassium bifluoride is gathered toward the center of the reaction chamber 11 by the centripetal force and then sinks to the guide protrusion 21 of the deformation member 2, the potassium bifluoride that has been gathered and sunk is flushed outward by the spiral guidance of the ethyl dichloroacetate solvent by the plurality of guiding fine grooves, thereby increasing the rate at which the potassium bifluoride expands outward between the deformation member 2 and the inner wall of the reaction chamber 11, thereby increasing the progress of the process of its expansion-dispersion, and reducing the probability of the potassium bifluoride staying on the guide protrusion 21, thereby ensuring the stability and efficiency of the cyclic motion of the potassium bifluoride powder in the reaction chamber 11 of gathering-sinking-expanding-dispersion, further improving the stirring effect and reaction efficiency, that is, further ensuring the reaction efficiency of potassium bifluoride and ethyl dichloroacetate.

[0105] After step S3, the following steps are also included:

[0106] S4, after the control adjustment driving device 3 slowly pushes up the deformable member 2 so that the upper arch protrudes above the bottom wall of the reaction chamber 11 to form the guide protrusion 21, the solid phase material in the collecting groove 22 is exposed to the top surface of the guide boss and the opened several guide grooves, and the remaining small amount of ethyl difluoroacetate in the collecting groove 22 slides down to between the deformable member 2 and the inner wall of the reaction chamber 11, and the hydrogen fluoride gas from the outside reacts with the potassium fluoride in the solid phase material to generate potassium hydrogen fluoride.

[0107] Therefore, through the reaction treatment of hydrogen fluoride gas and solid-phase materials, the collected product potassium fluoride is converted back to potassium bifluoride and then continues to be used as a reaction raw material for preparing ethyl difluoroacetate, so as to realize the repeated utilization of the product potassium fluoride and unreacted potassium bifluoride. Under the condition of the same volume of potassium bifluoride raw material, the volume of ethyl difluoroacetate product that can be generated is increased, the preparation rate of ethyl difluoroacetate is increased, and the efficiency of repeated utilization of the product potassium fluoride and unreacted potassium bifluoride is increased, and no external filtering device is required for filtering and then returning.

[0108] After step S4, the following steps are also included:

[0109] S5, after the gas phase material is introduced into the aqueous solution to absorb the hydrogen chloride, the remaining hydrogen fluoride gas is combined with the external hydrogen fluoride gas and introduced into the reaction container 1 to react with the potassium fluoride in the solid phase material to generate potassium hydrogen fluoride.

[0110] After the gas phase material is absorbed by the aqueous solution, the remaining hydrogen fluoride gas is used to assist the external hydrogen fluoride gas to convert the returned solid phase material back into potassium hydrogen fluoride, so as to realize the reuse of the product hydrogen fluoride gas, which can reduce the external hydrogen fluoride gas required in step S4 and reduce the reuse cost of the solid phase material. At the same time, the reuse of hydrogen fluoride can avoid the impact of hydrogen fluoride discharged into the air on the environment, and can also save the environmental protection treatment cost of hydrogen fluoride.

[0111] The preparation steps of ethyl difluoroacetate in this embodiment:

[0112] S1, after the driving device 3 is controlled to push the upper arch of the deformable member 2 to protrude above the bottom wall of the reaction chamber 11 to form a guide protrusion 21, a plurality of the guide grooves 23 are opened and used for guide flow, and ethyl dichloroacetate and potassium bifluoride are mixed, stirred and heated in the reaction container 1 to react;

[0113] S2, after the control and adjustment driving device 3 pulls down the deformable member 2 so that the concave and convex part is below the bottom wall of the reaction chamber 11 to form a collecting groove 22, the rotation driving device 13 is turned off to stop the stirring of the plurality of stirring members 12, so that the liquid phase material in the reaction chamber 11 continues to rotate under the action of inertia to form a centripetal force and gradually decelerates, and the solid phase material in the reaction chamber 11 is collected at the center of the reaction chamber 11 under the action of the centripetal force and gradually sinks and collects in the collecting groove 22, and after the reaction container 1 is left to stand for a certain period of time, the ethyl difluoroacetate and ethyl dichloroacetate in the reaction chamber 11 are discharged through the discharge port 15;

[0114] S3, inputting the ethyl difluoroacetate and ethyl dichloroacetate outputted from the discharge port 15 into a distillation tower for distillation and purification to obtain ethyl difluoroacetate;

[0115] S4, controlling the adjusting driving device 3 to slowly push up the deformable member 2 so that the upper arch protrudes above the bottom wall of the reaction chamber 11 to form a guide protrusion 21, and the solid phase material in the collecting groove 22 is exposed to the top surface of the guide protrusion and the opened plurality of guide grooves, and the remaining small amount of ethyl difluoroacetate in the collecting groove 22 slides down to between the deformable member 2 and the inner wall of the reaction chamber 11, and the hydrogen fluoride gas introduced from the outside reacts with the potassium fluoride in the solid phase material to generate potassium hydrogen fluoride;

[0116] S5, after the gas phase material is introduced into the aqueous solution to absorb the hydrogen chloride, the remaining hydrogen fluoride gas is merged with the external hydrogen fluoride gas and introduced into the reaction container 1 to react with the potassium fluoride in the solid phase material to generate potassium hydrogen fluoride;

[0117] S6, returning the ethyl dichloroacetate solution at the bottom of the distillation tower to the reaction vessel 1.

[0118] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing ethyl difluoroacetate, characterized in that: The steps include: S1, ethyl dichloroacetate and potassium bifluoride are mixed, stirred and heated in a reaction container (1) to carry out a reaction; S2, after the reaction is completed, solid phase material, liquid phase material and gas phase material are generated, and the solid phase material and the liquid phase material are separated; S3, distilling and purifying the separated liquid phase material to obtain ethyl difluoroacetate.

2. The method for preparing ethyl difluoroacetate according to claim 1, wherein In step S1, the heating temperature of the reaction container (1) is 100°C-130°C, and the reaction time of ethyl dichloroacetate and potassium bifluoride is 2h-6h.

3. A method for preparing ethyl difluoroacetate as claimed in claim 1, characterized in that, In step S1, the molar ratio of potassium bifluoride to ethyl dichloroacetate is 2.5:

1.

4. The method for preparing ethyl difluoroacetate according to claim 1, wherein The solid phase material includes potassium fluoride and unreacted potassium bifluoride, the liquid phase material includes ethyl difluoroacetate and unreacted ethyl dichloroacetate, and the gas phase material includes hydrogen chloride gas and hydrogen fluoride gas; After step S3, the following steps are also included: S4, returning the separated solid phase material to the reaction container (1), introducing hydrogen fluoride gas from the outside to react with potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride.

5. A method for preparing ethyl difluoroacetate as claimed in claim 4, characterized in that, After step S4, the following steps are also included: S5, after the gas phase material is introduced into the aqueous solution to absorb the hydrogen chloride, the remaining hydrogen fluoride gas is combined with the external hydrogen fluoride gas and introduced into the reaction container (1) to react with the potassium fluoride in the returned solid phase material to generate potassium hydrogen fluoride.

6. A method for preparing ethyl difluoroacetate as claimed in claim 5, characterized in that, Step S3 specifically comprises: inputting the separated liquid phase material into a distillation tower for distillation and purification to obtain ethyl difluoroacetate; the ethyl difluoroacetate and unreacted ethyl dichloroacetate are distilled to the top and bottom of the distillation tower respectively, the bottom temperature of the distillation tower is 110° C.-150° C., the top temperature is 90° C.-110° C., and the reflux ratio is 4-10; After step S5, the following steps are also included: S6, returning the ethyl dichloroacetate solution at the bottom of the distillation tower to the reaction container (1).

7. A preparation device for a method for preparing ethyl difluoroacetate as claimed in any one of claims 1 to 6, characterized in that: include: A reaction container (1) comprises a reaction chamber (11) for a mixed reaction of ethyl dichloroacetate and potassium hydrogen fluoride, and a stirring member (12) driven by a rotary driving device (13) to rotate and stir in the reaction chamber (11); A separation structure, used for separating the solid phase material and the liquid phase material generated by the mixed reaction of ethyl dichloroacetate and potassium bifluoride; The distillation tower is used to distill and purify the liquid phase material separated by the separation structure to obtain ethyl difluoroacetate.

8. The preparation device according to claim 1, characterized in that: The reaction container (1) further comprises an adjusting chamber (14) separated from the bottom of the reaction chamber (11); an opening is passed through between the reaction chamber (11) and the adjusting chamber (14) and a flexible deformable member (2) is sealed and embedded therein; an adjusting driving device (3) is arranged in the adjusting chamber (14) and the telescopic end of the adjusting driving device (3) is connected to the middle part of the bottom of the deformable member (2); the separation structure comprises the deformable member (2) and the adjusting driving device (3); a plurality of stirring members (12) are arranged and are circumferentially spaced and distributed between the deformable member (2) and the inner wall of the reaction chamber (11); the discharge port (15) of the reaction container (1) corresponds to the inner bottom of the reaction chamber (11); when the telescopic end of the adjusting driving device (3) is pushed up, the deformable member (2) is arched and protrudes above the bottom wall of the reaction chamber (11) to form a guiding protrusion (21); when the telescopic end of the adjusting driving device (3) is pulled down, the deformable member (2) is concave and protrudes below the bottom wall of the reaction chamber (11) to form a collecting groove (22).

9. The preparation device according to claim 8, characterized in that: The top of the deformable member (2) is provided with a plurality of flow-guiding grooves (23) which are distributed at intervals in the circumferential direction and extend spirally from the center to the periphery, and the spiral direction of the flow-guiding grooves (23) is consistent with the rotation and stirring direction of the stirring member (12); when the deformable member (2) is arched upward to form the guide protrusion (21), the plurality of flow-guiding grooves (23) are opened and used for guiding flow, and when the deformable member (2) is concave downward to form the collecting groove (22), the plurality of flow-guiding grooves (23) are squeezed and closed.

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