Device and method for preparing electronic grade triethyl phosphate

Abstract

The invention relates to the field of high-purity electronic gas preparation, in particular to a device and a method for preparing electronic-grade triethyl phosphate. The device comprises a reactive distillation tower, an adsorption tower, a light component removal tower, a heavy component removal tower and a product tank, the bottom of the reactive distillation tower is communicated with the bottom of the adsorption tower through a first pipeline, the top of the adsorption tower is communicated with the light component removal tower through a second pipeline, the bottom of the light component removal tower is communicated with the heavy component removal tower through a third pipeline, and the top of the heavy component removal tower is communicated with the product tank through a fourth pipeline; the bottom and the side part of the product tank are communicated through a fifth pipeline; a second filter and a liquid conveying pump are arranged on the fifth pipeline; and a first filter is arranged on the first pipeline. The preparation method comprises the following steps: reacting ethanol with phosphorus oxychloride under the action of a catalyst to generate a crude product triethyl phosphate; dehydrating the crude product triethyl phosphate, and then carrying out primary filtration and primary rectification to remove light components; and carrying out secondary rectification to remove heavy components, and carrying out secondary filtration to finally obtain the electronic-grade triethyl phosphate.

Description

Technical Field

[0001] The present application relates to the field of high-purity electronic gas preparation, and specifically to a device and method for preparing electronic-grade triethyl phosphate. Background Art

[0002] Triethyl phosphate (TEPO for short) is a colorless and odorless liquid with a high boiling point and good solubility. It is widely used as a solvent, plasticizer, and softener in the rubber and plastic industry. It is also a raw material for the preparation of pesticides, and can be used as an insecticide stabilizer and a plant growth regulator. With the continuous development of the electronics industry, electronic-grade triethyl phosphate is also widely used as an important electronic chemical required for the production of semiconductors, discrete devices, and microelectromechanical systems (MEMS). It is often used in the wafer production process to deposit phosphosilicate glass (PSG) and is an important material required for the thin film deposition process in the front-end manufacturing of semiconductor chips.

[0003] At present, ethanol and phosphorus oxychloride are usually used as reactants to carry out esterification reaction to generate triethyl phosphate, and then other impurities such as ethanol and hydrogen chloride are removed to obtain industrial-grade triethyl phosphate, and then a high-purity product is obtained by further distillation and purification. For example, the Chinese patent with the announcement number CN102675359B discloses a method for preparing triethyl phosphate, in which phosphorus oxychloride and anhydrous ethanol are subjected to low-pressure esterification reaction, and then excess anhydrous ethanol and part of hydrogen chloride are removed under reduced pressure, residual hydrogen chloride is removed under normal pressure, and vacuum distillation is carried out to obtain a triethyl phosphate finished product, and the temperature of the esterification reaction is reduced and the reaction speed is increased by adding a catalyst, but since the reaction product and the raw material are not separated in time, the catalyst may be wrapped, and as the reaction proceeds, the catalytic efficiency decreases, and the yield of the product also decreases.

[0004] In order to further improve the production process, a Chinese patent with announcement number CN117886852A discloses a triethyl phosphate and a synthesis process thereof, in which phosphorus oxychloride and ethanol are used as reaction raw materials and polyethylene glycol composite montmorillonite is used as a catalyst. However, the preparation process of the catalyst polyethylene glycol composite montmorillonite is relatively complicated, and the montmorillonite in the catalyst is loaded with metals and polyethylene glycol through physical activation intercalation. Therefore, during the reaction process, the properties of the catalyst may be unstable, and some other products may be generated, affecting the subsequent purification of the product. The Chinese patent with announcement number CN114057787A discloses a method for preparing triethyl phosphate. The method comprises three-stage esterification reaction of phosphorus oxychloride and excess ethanol under negative pressure. The reaction temperatures of the three-stage reaction are 2-5°C, 12-15°C, and 22-25°C, respectively. After the second-stage reaction is completed at 12-15°C, the reaction kettle enters the third-stage reaction kettle, and first removes ethanol and hydrogen chloride, and then adds an equal weight of fresh ethanol, and continues to react at 22-25°C until the reaction is complete. The mixed solution obtained by the reaction is then de-alcoholized and de-hydrochlorinated by a degassing device, and finally distilled to obtain a finished product. However, fresh ethanol is added after the third-stage reaction to promote the reaction, resulting in a waste of raw materials, and the addition of excess ethanol causes certain difficulties for subsequent purification.

[0005] With the continuous development of the electronics industry, the development space of electronic-grade triethyl phosphate is constantly expanding. In the prior art, there are many reports on the preparation of triethyl phosphate, but its production process still has problems such as low raw material conversion rate, unreasonable production process, and imperfect product indicators. It is difficult to meet the use requirements of the electronics industry. It is urgent to develop an electronic-grade triethyl phosphate device and method that can realize industrial production, has high product purity, and is energy-saving and environmentally friendly. Summary of the invention

[0006] In view of the fact that the preparation process of triethyl phosphate in the prior art has the problems of low raw material conversion rate, unreasonable production process, imperfect product indicators and the like, it is difficult to meet the use requirements of the electronics industry. The present application provides a device and method for preparing electronic grade triethyl phosphate.

[0007] The technical solution of this application:

[0008] On the one hand, the present application provides an apparatus for preparing electronic-grade triethyl phosphate, comprising a reaction distillation tower, an adsorption tower, a lightness removal tower, a heaviness removal tower and a product tank; the bottom of the reaction distillation tower is connected to the bottom of the adsorption tower through a first pipeline, the top of the adsorption tower is connected to the lightness removal tower through a second pipeline, the bottom of the lightness removal tower is connected to the heaviness removal tower through a third pipeline, and the top of the heaviness removal tower is connected to the product tank through a fourth pipeline; the bottom and the side of the product tank are connected through a fifth pipeline, and a second filter and a liquid delivery pump are provided on the fifth pipeline; and a first filter is provided on the first pipeline.

[0009] Preferably, the top of the reaction distillation tower is provided with an impurity gas outlet, and the side of the reaction distillation tower is provided with an ethanol feed inlet and a phosphorus oxychloride feed inlet; the top of the light-removing tower is provided with a light component extraction outlet; the bottom of the heavy-removing tower is provided with a heavy component extraction outlet.

[0010] Preferably, the reactive distillation tower is provided with a distillation section, a reaction section, and a stripping section. The number of plates in the distillation section is 5 to 30, the number of plates in the reaction section is 10 to 40, and the number of plates in the stripping section is 5 to 30.

[0011] Preferably, the first filter and the second filter are both made of high-density polyethylene, and the pore sizes are both 0.1-2 μm. The light-removal tower, heavy-removal tower and product tank are all electropolished or lined with PFA material.

[0012] In a second aspect, the present application provides a method for preparing electronic grade triethyl phosphate, comprising the following steps:

[0013] Step S1. reacting ethanol and phosphorus oxychloride in the presence of a catalyst to produce crude triethyl phosphate;

[0014] Step S2. drying the crude triethyl phosphate, followed by primary filtration, and then primary distillation to remove light components;

[0015] Step S3: subjecting the triethyl phosphate obtained by the primary distillation to secondary distillation to remove heavy components, and then subjecting the triethyl phosphate to secondary filtration to obtain electronic grade triethyl phosphate.

[0016] Preferably, in step S1, the purity of ethanol and phosphorus oxychloride are both industrial pure, the molar ratio of ethanol to phosphorus oxychloride is (1-5):1, and the water content of ethanol is 0-0.5%.

[0017] Preferably, the catalyst in step S1 is anhydrous MgCl 2 、Anhydrous CuCl 2 、Anhydrous ZnCl 2 and anhydrous TiCl 4 Any one of .

[0018] Preferably, in step S2, any one of zeolite molecular sieve, phosphorus pentoxide and calcium chloride is used as a desiccant to achieve drying in step S2.

[0019] Preferably, the temperature of the primary distillation in step S2 is 30-70°C, the reflux ratio is 5-10, and the pressure is P 1 , the P 1 The range is 2KPa≤P 1 ≤10KPa; the temperature of the secondary distillation in S3 is 70~120℃, the reflux ratio is 5~10, and the pressure is P 2, the P 2 The range is 1KPa≤P 2 ≤9KPa, and the P 2 Less than P 1 .

[0020] Beneficial effects of this application:

[0021] The present application first introduces the purchased reactant raw materials into the reaction distillation tower for reaction, thereby obtaining a preliminary crude product. These crude products are then passed into an adsorption tower to remove the moisture contained therein and ensure the smooth progress of subsequent steps. Subsequently, the crude product enters a primary filter, through which most of the particulate impurities are removed to improve the purity of the product. After preliminary purification treatment, the crude product is introduced into a light removal and heavy removal tower, through which light components and heavy components such as hydrogen chloride, ethanol, diethyl phosphate and diethyl chlorophosphate are removed, thereby obtaining high-purity triethyl phosphate. Finally, the obtained high-purity triethyl phosphate is introduced into a product tank for storage. In order to further ensure product quality, a liquid delivery pump is used to extract the product from the product tank, and the second-stage filter is passed for further filtering treatment, and finally an electronic-grade triethyl phosphate that meets the needs of high-end applications is obtained. In the reaction distillation stage, by means of reaction and separation coupling, the reaction and separation efficiency are strengthened, the selectivity of the reaction is improved, energy consumption and equipment costs are saved, and the light components at the top of the tower are recovered as reactants to achieve environmentally friendly reuse. An adsorption tower is used to remove moisture from the product before the light-removal tower, which not only controls the moisture in the product, but also reduces the production of hydrochloric acid by combining some hydrogen chloride and water to prevent corrosion to subsequent equipment. This application also optimizes the distillation operating temperature and pressure range, as well as the reasonable reflux ratio setting, which not only improves the purification efficiency, but also effectively reduces energy consumption, making the production process more economical and efficient. In order to ensure that the particulate matter meets the standard, filters are added after the adsorption tower and after the product tank, and a circulation pipeline is used to ensure that the particulate matter index of the product is stable and meets the standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of the device for preparing electronic grade triethyl phosphate in this application.

[0023] Figure symbols: 1. Reaction distillation tower; 2. First pipeline; 3. Adsorption tower; 4. Second pipeline; 5. First filter; 6. Third pipeline; 7. Fourth pipeline; 8. Product tank; 9. Delivery pump; 10. Second filter; 11. Light-removal tower; 12. Heavy-removal tower; 13. Fifth pipeline. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present application are described in detail below in combination with the preferred embodiments.

[0025] Device Embodiment

[0026] Reference Figure 1 The present embodiment provides a device for preparing electronic grade triethyl phosphate, comprising a reaction distillation tower 11. The reaction distillation tower 1 is provided with a distillation section, a reaction section and a stripping section from top to bottom. The number of plates in the distillation section, the reaction section and the stripping section is 5 to 30. The reaction distillation tower 1 is used for reacting ethanol and phosphorus oxychloride to generate crude triethyl phosphate and preliminarily separate the crude product. The reaction raw materials are introduced into the reaction distillation tower 1 through the ethanol feed port and the phosphorus oxychloride feed port on the side of the reaction distillation tower 1. Most of the ethanol, hydrogen chloride and other components are removed from the impurity gas at the top of the reaction distillation tower 1. The crude triethyl phosphate is collected at the bottom of the reaction distillation tower 1; it enters the adsorption tower 3 through the first pipeline 2 to remove moisture in the crude triethyl phosphate, and then the material passes through the first filter 5 on the second pipeline 4 to remove most of the particulate matter and residual particulate matter of the catalyst and adsorbent; it passes through the first filter 5 on the second pipeline 4 and enters the middle part of the light component removal tower 11, and the light component is extracted from the light component extraction outlet at the top of the light component removal tower 11, and the heavy component is collected at the bottom of the light component removal tower 11, and enters the middle part of the heavy component removal tower 12 through the third pipeline 6. In the deweighting tower 12, the heavy component is extracted from the heavy component extraction port at the bottom of the deweighting tower 12, and triethyl phosphate enters the product tank 8 from the top of the tower along the fourth pipeline 7; the bottom of the product tank 8 is connected to the side of the product pipe through the fifth pipeline 13, and the fifth pipeline 13 is provided with a delivery pump 9 and a second filter 10. The triethyl phosphate entering the product tank 8 is delivered to the second filter 10 by the liquid delivery pump 9 to remove most of the particulate matter. The filtered triethyl phosphate can be filled or circulated to the product tank 8 to ensure the stability of the product index.

[0027] The light removal tower 11, the heavy removal tower 12 and the product tank 8 can be electropolished or lined with PFA (perfluoroalkoxy polymer) material;

[0028] The delivery pump 9 can be a meterable pump such as a gear pump or a diaphragm pump;

[0029] The first filter 5 and the second filter 10 are both made of high-density polyethylene, and the pore sizes are both 0.1-2 μm.

[0030] Example 1

[0031] Based on the equipment provided in the equipment example, this embodiment provides a method for preparing electronic grade triethyl phosphate, and the specific steps are as follows:

[0032] Step S1. The purchased industrial-grade phosphorus oxychloride and ethanol are passed through a reaction distillation tower 1 at a molar ratio of 1:3, and the reaction distillation is carried out to form anhydrous MgCl 2As a catalyst, the operating temperature of the reaction distillation tower 1 is 30°C, the operating pressure is 5 kPa, the number of plates in the distillation section is 20, the number of plates in the reaction section is 30, and the number of plates in the stripping section is 15. The reactants are catalytically reacted and preliminarily separated, wherein most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reaction distillation tower 1, and the resulting crude triethyl phosphate is collected from the bottom of the tower.

[0033] Step S2. The crude triethyl phosphate collected at the bottom of the reaction distillation tower 1 enters the adsorption tower 3 through the first pipeline 2. The adsorption tower 3 uses zeolite molecular sieve as an adsorbent to remove moisture from the crude triethyl phosphate. Then it enters the second pipeline 4 and passes through the first filter 5 on the second pipeline 4 to remove most of the particulate matter and catalyst and adsorbent residual particulate matter. The filter uses a high-density polyethylene filter with a pore size of 0.2μm. The filtered material enters the light removal tower 11. The top temperature of the light removal tower 11 is 35°C, the top pressure is 4kPa, the reflux ratio is 9, 7°C water is used as the refrigerant, and 160°C heat transfer oil is used as the heat medium to remove light components such as hydrogen chloride, ethanol, and diethyl phosphate.

[0034] Step S3. The gas after light removal enters the de-weighting tower 12 through the third pipeline 6. The top temperature of the de-weighting tower 12 is 100°C, the top pressure of the de-weighting tower 12 is 3kPa, the reflux ratio is 9, 7°C water is used as a refrigerant, and 160°C heat transfer oil is used as a heat medium to remove heavy components such as diethyl chlorophosphate and most of the metal ions, and high-purity triethyl phosphate product is produced from the top of the tower. The high-purity triethyl phosphate product enters the product tank 8 through the fourth pipeline 7, the temperature is 20°C, and helium is used for pressurization, and the pressure is 0.2MPa. A gear pump is used to transport the material in the product tank 8 to the second filter 10 on the fifth pipeline 13. The second filter 10 uses a high-density polyethylene filter with an aperture of 0.2μm to remove particulate impurities and ensure that the product particle index is long-term stable. The filtered high-purity triethyl phosphate can be directly charged for use or returned to the product tank 8.

[0035] Example 2

[0036] Based on the equipment provided in the equipment example, this embodiment provides a method for preparing electronic grade triethyl phosphate, and the specific steps are as follows:

[0037] Step S1. The purchased industrial-grade phosphorus oxychloride and ethanol are passed through a reaction distillation tower 1 at a molar ratio of 1:1, and the reaction distillation is carried out to form anhydrous CuCl 2As a catalyst, the operating temperature of the reaction distillation tower 1 is 40°C, the operating pressure is 1 kPa, the number of plates in the distillation section is 25, the number of plates in the reaction section is 25, and the number of plates in the stripping section is 5. The reactants are catalytically reacted and preliminarily separated, wherein most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reaction distillation tower 1, and the resulting crude triethyl phosphate is collected from the bottom of the tower.

[0038] Step S2. The crude triethyl phosphate collected at the bottom of the reaction distillation tower 1 enters the adsorption tower 3 through the first pipeline 2. The adsorption tower 3 uses phosphorus pentoxide as an adsorbent to remove moisture from the crude triethyl phosphate. The gas then enters the second pipeline 4 and passes through the first filter 5 on the second pipeline 4 to remove most of the particulate matter and catalyst and adsorbent residual particulate matter, wherein the filter uses a high-density polyethylene filter with a pore size of 1 μm. The filtered material enters the light removal tower 11, the top temperature of the light removal tower 11 is 60°C, the top pressure is 2kPa, the reflux ratio is 8, 7°C water is used as the refrigerant, and 160°C heat transfer oil is used as the heat medium to remove light components such as hydrogen chloride, ethanol, and diethyl phosphate.

[0039] Step S3. The gas after light removal enters the de-weighting tower 12 through the third pipeline 6. The top temperature of the de-weighting tower 12 is 120°C, the top pressure of the de-weighting tower 12 is 1kPa, the reflux ratio is 8, 7°C water is used as a refrigerant, and 160°C heat transfer oil is used as a heat medium to remove heavy components such as diethyl chlorophosphate and most of the metal ions, and high-purity triethyl phosphate product is produced from the top of the tower. The high-purity triethyl phosphate product enters the product tank 8 through the fourth pipeline 7, the temperature is 30°C, and helium is used for pressurization, and the pressure is 0.1MPa. A gear pump is used to transport the material in the product tank 8 to the second filter 10 on the fifth pipeline 13. The second filter 10 uses a high-density polyethylene filter with an aperture of 1μm to remove particulate impurities and ensure that the product particle index is long-term stable. The filtered high-purity triethyl phosphate can be directly charged for use or returned to the product tank 8.

[0040] Example 3

[0041] Based on the equipment provided in the equipment example, this embodiment provides a method for preparing electronic grade triethyl phosphate, and the specific steps are as follows:

[0042] Step S1. The purchased industrial-grade phosphorus oxychloride and ethanol are passed through a reaction distillation tower 1 at a molar ratio of 1:4, and the reaction distillation is carried out to form anhydrous ZnCl 2As a catalyst, the operating temperature of the reaction distillation tower 1 is 0°C, the operating pressure is 9 kPa, the number of plates in the distillation section is 5, the number of plates in the reaction section is 40, and the number of plates in the stripping section is 30. The reactants are catalytically reacted and preliminarily separated, wherein most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reaction distillation tower 1, and the resulting crude triethyl phosphate is collected from the bottom of the tower.

[0043] Step S2. The crude triethyl phosphate collected at the bottom of the reaction distillation tower 1 enters the adsorption tower 3 through the first pipeline 2. The adsorption tower 3 uses zeolite molecular sieve as an adsorbent to remove moisture from the crude triethyl phosphate. The gas then enters the second pipeline 4 and passes through the first filter 5 on the second pipeline 4 to remove most of the particulate matter and catalyst and adsorbent residual particulate matter, wherein the filter uses a high-density polyethylene filter with a pore size of 0.1 μm. The filtered material enters the light removal tower 11, the top temperature of the light removal tower 11 is 30°C, the top pressure is 10kPa, the reflux ratio is 10, 7°C water is used as the refrigerant, and 160°C heat transfer oil is used as the heat medium to remove light components such as hydrogen chloride, ethanol, and diethyl phosphate.

[0044] Step S3. The gas after light removal enters the de-weighting tower 12 through the third pipeline 6. The top temperature of the de-weighting tower 12 is 90°C, the top pressure of the de-weighting tower 12 is 9kPa, the reflux ratio is 10, 7°C water is used as a refrigerant, and 160°C heat transfer oil is used as a heat medium to remove heavy components such as diethyl chlorophosphate and most of the metal ions, and high-purity triethyl phosphate products are produced from the top of the tower. The high-purity triethyl phosphate product enters the product tank 8 through the fourth pipeline 7, the temperature is 5°C, and helium is used for pressurization, and the pressure is 0.05MPa. A gear pump is used to transport the material in the product tank 8 to the second filter 10 on the fifth pipeline 13. The second filter 10 uses a high-density polyethylene filter with an aperture of 0.1μm to remove particulate impurities and ensure that the product particle index is long-term stable. The filtered high-purity triethyl phosphate can be directly charged for use or returned to the product tank 8.

[0045] Example 4

[0046] Based on the equipment provided in the equipment example, this embodiment provides a method for preparing electronic grade triethyl phosphate, and the specific steps are as follows:

[0047] Step S1. The purchased industrial-grade phosphorus oxychloride and ethanol are passed through a reaction distillation tower 1 at a molar ratio of 1:5, and the reaction distillation is carried out to form anhydrous TiCl 4As a catalyst, the operating temperature of the reaction distillation tower 1 is 40°C, the operating pressure is 10kPa, the number of plates in the distillation section is 30, the number of plates in the reaction section is 15, and the number of plates in the stripping section is 25. The reactants are catalytically reacted and preliminarily separated, wherein most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reaction distillation tower 1, and the resulting crude triethyl phosphate is collected from the bottom of the tower.

[0048] Step S2. The crude triethyl phosphate collected at the bottom of the reaction distillation tower 1 enters the adsorption tower 3 through the first pipeline 2. The adsorption tower 3 uses calcium chloride as an adsorbent to remove moisture from the crude triethyl phosphate. The gas then enters the second pipeline 4 and passes through the second filter 10 on the second pipeline 4 to remove most of the particulate matter and the catalyst and adsorbent residual particulate matter, wherein the filter uses a high-density polyethylene filter with a pore size of 2μm. The filtered material enters the light removal tower 11, the top temperature of the light removal tower 11 is 70°C, the top pressure is 8kPa, the reflux ratio is 5, 7°C water is used as the refrigerant, and 160°C heat transfer oil is used as the heat medium to remove light components such as hydrogen chloride, ethanol, and diethyl phosphate.

[0049] Step S3. The gas after light removal enters the de-weighting tower 12 through the third pipeline 6. The top temperature of the de-weighting tower 12 is 70°C, the top pressure of the de-weighting tower 12 is 5kPa, the reflux ratio is 5, 7°C water is used as a refrigerant, and 160°C heat transfer oil is used as a heat medium to remove heavy components such as diethyl chlorophosphate and most of the metal ions, and high-purity triethyl phosphate products are produced from the top of the tower. The high-purity triethyl phosphate product enters the product tank 8 through the fourth pipeline 7, the temperature is 25°C, and helium is used for pressurization, and the pressure is 0.09MPa. A diaphragm pump is used to transport the material in the product tank 8 to the second filter 10 on the fifth pipeline 13. The second filter 10 uses a high-density polyethylene filter with an aperture of 2μm to remove particulate impurities and ensure that the product particle index is long-term stable. The filtered high-purity triethyl phosphate can be directly charged for use or returned to the product tank 8.

[0050] Performance Analysis

[0051] Under the process conditions of Examples 1 to 4, after testing, the purity of the prepared electronic-grade triethyl phosphate is not less than 99.99%, the moisture content is not higher than 20 ppm, the metal ion impurities meet the 8.5N purity, and the particle index (≥0.2 μm) is not higher than 10 p / ml, which can meet production needs.

[0052] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A device for preparing electronic grade triethyl phosphate, characterized in that: The invention comprises a reaction distillation tower (1), an adsorption tower (3), a lightness removal tower (11), a weight removal tower (12) and a product tank (8); the bottom of the reaction distillation tower (1) is connected to the bottom of the adsorption tower (3) through a first pipeline (2), the top of the adsorption tower (3) is connected to the lightness removal tower (11) through a second pipeline (4), the bottom of the lightness removal tower (11) is connected to the weight removal tower (12) through a third pipeline (6), and the top of the weight removal tower (12) is connected to the product tank (8) through a fourth pipeline (7); the bottom and the side of the product tank (8) are connected through a fifth pipeline (13), and a second filter (10) and a liquid delivery pump (9) are provided on the fifth pipeline (13); and a first filter (5) is provided on the first pipeline (2).

2. A device for preparing electronic grade triethyl phosphate according to claim 1, characterized in that, The top of the reaction distillation tower (1) is provided with an impurity gas outlet, and the side of the reaction distillation tower (1) is provided with an ethanol feed inlet and a phosphorus oxychloride feed inlet; the top of the light component removal tower (11) is provided with a light component extraction outlet; and the bottom of the heavy component removal tower (12) is provided with a heavy component extraction outlet.

3. A device for preparing electronic grade triethyl phosphate according to claim 1, characterized in that, The reactive distillation tower (1) is provided with a distillation section, a reaction section and a stripping section. The number of plates in the distillation section is 5 to 30, the number of plates in the reaction section is 10 to 40, and the number of plates in the stripping section is 5 to 30.

4. A device for preparing electronic grade triethyl phosphate according to claim 1, characterized in that, The first filter (5) and the second filter (10) are both made of high-density polyethylene, and their pore sizes are both 0.1 to 2 μm. The light removal tower (11), heavy removal tower (12) and product tank (8) are all electrolytically polished or lined with PFA material.

5. A method for preparing electronic grade triethyl phosphate, based on the device for preparing electronic grade triethyl phosphate according to any one of claims 1 to 4, characterized in that: The steps include: Step S1. reacting ethanol and phosphorus oxychloride in the presence of a catalyst to produce crude triethyl phosphate; Step S2. drying the crude triethyl phosphate, followed by primary filtration, and then primary distillation to remove light components; Step S3: subjecting the triethyl phosphate obtained by the primary distillation to secondary distillation to remove heavy components, and then subjecting the triethyl phosphate to secondary filtration to obtain electronic grade triethyl phosphate.

6. A method for preparing electronic-grade triethyl phosphate according to claim 5, characterized in that, In step S1, the purity of ethanol and phosphorus oxychloride are both industrial pure, the molar ratio of ethanol to phosphorus oxychloride is (1-5):1, and the water content of ethanol is 0-0.5%.

7. A method for preparing electronic-grade triethyl phosphate according to claim 5, characterized in that, The catalyst in step S1 is any one of anhydrous MgCl2, anhydrous CuCl2, anhydrous ZnCl2 and anhydrous TiCl4.

8. A method for preparing electronic-grade triethyl phosphate according to claim 5, characterized in that, In the step S2, any one of zeolite molecular sieve, phosphorus pentoxide and calcium chloride is used as a desiccant to achieve drying in step S2.

9. A method for preparing electronic-grade triethyl phosphate according to claim 5, characterized in that, In the step S2, the temperature of the primary distillation is 30-70°C, the reflux ratio is 5-10, and the pressure is P1, and the range of P1 is 2KPa≤P1≤10KPa; in S3, the temperature of the secondary distillation is 70-120°C, the reflux ratio is 5-10, and the pressure is P2, and the range of P2 is 1KPa≤P2≤9KPa, and P2 is less than P1.

Images