Apparatus and method for producing electronic grade triethyl phosphate

Abstract

The application relates to the field of high-purity electronic gas preparation, in particular to a device and method for preparing electronic-grade triethyl phosphate. The device comprises a reaction rectifying tower, an adsorption tower, a light-removing tower, a heavy-removing tower and a product tank; the bottom of the reaction rectifying 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-removing tower through a second pipeline, the bottom of the light-removing tower is communicated with the heavy-removing tower through a third pipeline, and the top of the heavy-removing tower is communicated with the product tank through a fourth pipeline; the bottom of the product tank is communicated with the side 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 device is used for reacting ethanol and phosphorus oxychloride under the action of a catalyst to generate crude triethyl phosphate; the crude triethyl phosphate is dehydrated, then subjected to primary filtration and primary rectification to remove light components; secondary rectification is further conducted to remove heavy components, secondary filtration is further conducted, and finally, electronic-grade triethyl phosphate is obtained.

Description

TECHNICAL FIELD

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

[0002] Triethyl phosphate (TEPO for short) is a colorless and odorless liquid with 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 used as a raw material for pesticide preparation, as a stabilizer for insecticides, and as a plant growth regulator. With the continuous development of the electronics industry, electronic-grade triethyl phosphate is widely used as an important electronic chemical for the production of semiconductors, discrete devices and micro-electro-mechanical systems (MEMS). It is commonly used in the deposition of phosphosilicate glass (PSG) during wafer manufacturing. It is an important material required for the thin film deposition process in the front-end manufacturing of semiconductor chips.

[0003] Currently, ethanol and phosphorus oxychloride are commonly used as reactants for esterification to produce triethyl phosphate. Then, ethanol, hydrogen chloride and other impurities are removed to obtain industrial-grade triethyl phosphate. Further purification by rectification is used to obtain high-purity products. For example, Chinese patent CN102675359B discloses a method for preparing triethyl phosphate. In this method, after low-pressure esterification of phosphorus oxychloride and anhydrous ethanol, excess anhydrous ethanol and part of hydrogen chloride are removed under reduced pressure, residual hydrogen chloride is removed under normal pressure, and then triethyl phosphate is obtained by reduced pressure distillation. The addition of a catalyst reduces the temperature of the esterification reaction and increases the reaction speed. However, since the reaction products and raw materials are not separated in time, the catalyst may be encapsulated, which reduces the catalytic efficiency and the yield of the product as the reaction proceeds.

[0004] In order to further improve the production process, a Chinese patent with publication number CN117886852A discloses a kind of triethyl phosphate and its synthesis process, which uses phosphorus oxychloride and ethanol as reaction raw materials, and polyethylene glycol complex montmorillonite as catalyst, but the preparation process of its catalyst polyethylene glycol complex montmorillonite is relatively complex, and the montmorillonite in the catalyst is intercalated by physical activation, loaded with metal and polyethylene glycol, so in the reaction process, the properties of the catalyst may not be stable, and some other products may be generated, affecting the subsequent purification of the product.A Chinese patent with publication number CN114057787A discloses a kind of preparation method of triethyl phosphate, which carries out three-stage esterification reaction of raw material phosphorus oxychloride and excess ethanol under negative pressure, and the reaction temperatures of the three stages are 2-5℃, 12-15℃ and 22-25℃ respectively.After the second stage reaction is completed at 12-15℃, the reaction mixture is transferred to the third stage reaction kettle, and then the ethanol and hydrogen chloride are removed, and fresh ethanol of the same weight is added, and the reaction is continued at 22-25℃ until the reaction is completed.The mixture obtained by the reaction is dehydrated and dehydrochlorinated by a degassing device, and then the finished product is obtained by rectification, but the addition of fresh ethanol after the third stage reaction promotes the reaction, resulting in waste of raw materials, and the addition of excess ethanol makes the subsequent purification difficult.

[0005] With the continuous development of electronic industry, the development space of electronic grade triethyl phosphate is continuously expanding, and there are many reports on the preparation of triethyl phosphate in the prior art, but the production process still has problems such as low raw material conversion rate, unreasonable production process, imperfect product index, etc., which is difficult to meet the use requirements of electronic industry, and it is urgent to develop a device and method for producing electronic grade triethyl phosphate with high purity, energy saving and environmental protection. SUMMARY

[0006] In view of the problems in the prior art, such as low raw material conversion rate, unreasonable production process, imperfect product index, etc., which are difficult to meet the use requirements of electronic industry, the present application provides a device and method for preparing electronic grade triethyl phosphate.

[0007] The technical scheme of the present application:

[0008] In one aspect, the present application provides a device for preparing electronic grade triethyl phosphate, which comprises a reaction rectification tower, an adsorption tower, a light removal tower, a heavy removal tower and a product tank; the bottom of the reaction rectification tower is connected to the bottom of the adsorption tower through a first pipeline, the top of the adsorption tower is connected to the light removal tower through a second pipeline, the bottom of the light removal tower is connected to the heavy removal tower through a third pipeline, and the top of the heavy 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, a second filter and a liquid delivery pump are arranged on the fifth pipeline, and a first filter is arranged on the first pipeline.

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

[0010] Preferably, the reaction rectification tower is internally provided with a rectification section, a reaction section and a stripping section, the number of plates of the rectification section is 5-30, the number of plates of the reaction section is 10-40, and the number of plates of the stripping section is 5-30.

[0011] Preferably, the material of the first filter and the second filter is high-density polyethylene, and the pore size is 0.1-2 μm; the light component removal tower, the heavy component removal tower and the product tank are all electrolytic polished or lined with PFA material.

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

[0013] Step S1. Reacting ethanol and phosphorus oxychloride under the action of a catalyst to generate crude triethyl phosphate;

[0014] Step S2. Drying the crude triethyl phosphate, then performing primary filtration, and then removing light components through primary rectification;

[0015] Step S3. Removing heavy components from the triethyl phosphate obtained through primary rectification through secondary rectification, then performing secondary filtration, and finally obtaining electronic-grade triethyl phosphate.

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

[0017] Preferably, in step S1, the catalyst is any one of anhydrous MgCl2, anhydrous CuCl2, anhydrous ZnCl2 and anhydrous TiCl4.

[0018] Preferably, in step S2, any one of zeolite molecular sieve, diaphthide and calcium chloride is used as a drying agent to realize the drying in step S2.

[0019] Preferably, in step S2, the temperature of primary rectification is 30-70℃, the reflux ratio is 5-10, and the pressure is P1, the range of P1 is 2KPa≤P1≤10KPa; in step S3, the temperature of secondary rectification is 70-120℃, the reflux ratio is 5-10, and the pressure is P2, the range of P2 is 1KPa≤P2≤9KPa, and P2 is less than P1.

[0020] The application has the following beneficial effects:

[0021] The application first introduces the purchased reaction raw material into the reaction rectification tower for reaction, thereby obtaining the preliminary crude product. Then the crude product is introduced into the adsorption tower to remove the water contained therein, ensuring the smooth progress of the subsequent steps. Subsequently, the crude product enters the first filter, and most of the particulate impurities are removed through the filter to improve the purity of the product. After preliminary purification, the crude product is introduced into the light component removal tower and the heavy component removal tower, and the light components and heavy components such as hydrogen chloride, ethanol, diethyl phosphate and chloro diethyl phosphate are removed through the tower, thereby obtaining high-purity triethyl phosphate. Finally, the obtained high-purity triethyl phosphate is introduced into the product tank for storage. In order to further ensure the product quality, the product is pumped out from the product tank by using a liquid delivery pump and introduced into the second filter for further filtration treatment, and finally the electronic-grade triethyl phosphate meeting the needs of high-end applications is obtained. In the reaction rectification stage, the reaction and separation are coupled, the reaction and separation efficiency is strengthened, the reaction selectivity is improved, the energy consumption and equipment cost are saved, the light components at the top of the tower are recycled as reactants, and environmental protection and reuse are realized. The adsorption tower is used before the light component removal tower to remove the water in the product, which not only controls the water in the product, but also reduces the generation of hydrochloric acid by combining part of hydrogen chloride and water, preventing corrosion of the subsequent equipment. The application also optimizes the distillation operation temperature and pressure range, and reasonably sets the reflux ratio, which not only improves the purification efficiency, but also effectively reduces the 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 the product tank, and a circulating pipeline is used to ensure that the particulate matter index of the product is stable and meets the standard. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The device diagram for preparing electronic-grade triethyl phosphate according to the application.

[0023] The drawing identification: 1, reaction rectification 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 component removal tower; 12, heavy component removal tower; 13, fifth pipeline. DETAILED DESCRIPTION

[0024] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined purpose of the application, the specific implementation, structure, features and effects according to the application are described in detail as follows in combination with the preferred embodiments.

[0025] Device embodiment

[0026] Reference Figure 1The embodiment provides a device for preparing electronic-grade triethyl phosphate, which comprises a reaction rectifying tower 1, the inside of the reaction rectifying tower 1 is provided with a rectifying section, a reaction section and a stripping section from top to bottom, the number of plates of the rectifying section, the reaction section and the stripping section is 5-30, crude triethyl phosphate is generated by reacting ethanol and phosphorus oxychloride, and the crude product is preliminarily separated, the reaction raw materials are introduced into the reaction rectifying tower 1 through an ethanol feeding port and a phosphorus oxychloride feeding port on the side of the reaction rectifying tower 1, most of the ethanol, hydrogen chloride and other components are collected from a tower top impurity gas outlet of the reaction rectifying tower 1, and the generated crude triethyl phosphate is collected at the bottom of the reaction rectifying tower 1; the crude triethyl phosphate is introduced into an adsorption tower 3 through a first pipeline 2, moisture in the crude triethyl phosphate is removed, then the material passes through a first filter 5 on a second pipeline 4, most of the particulate matters and catalyst and adsorbent residual particulate matters are removed, the material passes through the first filter 5 on the second pipeline 4 and enters the middle part of a light component removal tower 11, light components are collected from a tower top light component collection outlet of the light component removal tower 11, heavy components are collected at the bottom of the light component removal tower 11 and are introduced into the middle part of a heavy component removal tower 12 through a third pipeline 6. In the heavy component removal tower 12, the heavy components are collected from a tower bottom heavy component collection outlet of the heavy component removal tower 12, and the triethyl phosphate is introduced into a product tank 8 from the top of the heavy component removal tower 12 through a fourth pipeline 7; the bottom of the product tank 8 and the side of a product pipe are connected through a fifth pipeline 13, a delivery pump 9 and a second filter 10 are arranged on the fifth pipeline 13, the triethyl phosphate in the product tank 8 is delivered to the second filter 10 through the liquid delivery pump 9, most of the particulate matters are removed, the filtered triethyl phosphate can be filled or recycled to the product tank 8, so that the indexes of the product are stable.

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

[0028] The delivery pump 9 can be a gear pump, a diaphragm pump or the like.

[0029] The material of the first filter 5 and the second filter 10 is high-density polyethylene, and the pore size is 0.1-2 μm.

[0030] Embodiment 1

[0031] Based on the device provided in the device embodiment, the 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 the reaction rectification column 1 in a molar ratio of 1:3, the reaction rectification is carried out with anhydrous MgCl2 as the catalyst for the regular packing, the operating temperature of the reaction rectification column 1 is 30℃, the operating pressure is 5kPa, the number of plates in the rectification 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 subjected to catalytic reaction and preliminary separation, most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reaction rectification column 1, and the product triethyl phosphate crude product is collected from the bottom of the column.

[0033] Step S2. The triethyl phosphate crude product collected from the bottom of the reaction rectification column 1 is passed through the first pipeline 2 into the adsorption column 3, the adsorption column 3 uses zeolite molecular sieve as the adsorbent to remove the water in the triethyl phosphate crude product. Then enter the second pipeline 4, and pass through the first filter 5 on the second pipeline 4 to remove most of the particulate matter and catalyst, adsorbent residual particles, wherein the filter uses a high-density polyethylene filter with a pore size of 0.2μm. The filtered material enters the light-removing column 11, the light-removing column 11 has a top temperature of 35℃, a top pressure of 4kPa, a reflux ratio of 9, uses 7℃ water as the coolant, and uses 160℃ heat-conducting oil as the heating medium to remove hydrogen chloride, ethanol, diethyl phosphate and other light components.

[0034] Step S3. The gas after light removal is passed through the third pipeline 6 into the heavy-removing column 12, the heavy-removing column 12 has a top temperature of 100℃, a top pressure of 3kPa, a reflux ratio of 9, uses 7℃ water as the coolant, and uses 160℃ heat-conducting oil as the heating medium to remove diethyl chlorophosphate and most of the metal ions, and the high-purity triethyl phosphate product is collected at the top. The high-purity triethyl phosphate product is passed through the fourth pipeline 7 into the product tank 8, the temperature is 20℃, and the product tank 8 is pressurized with helium gas, 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 a pore size of 0.2μm to remove particulate impurities and ensure long-term stability of the product particle index. The filtered high-purity triethyl phosphate can be directly filled with the product or returned to the product tank 8.

[0035] Example 2

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

[0037] Step S1. Procured industrial-grade phosphorus oxychloride and ethanol are passed through a reactive distillation tower 1 in a molar ratio of 1:1. The reactive distillation uses anhydrous CuCl2 with structured packing as a catalyst. The operating temperature of the reactive 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. Most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reactive distillation tower 1, and the crude product triethyl phosphate is collected from the bottom of the tower.

[0038] Step S2: The crude triethyl phosphate collected at the bottom of reactive distillation tower 1 enters adsorption tower 3 via first pipeline 2. Adsorption tower 3 uses phosphorus pentoxide as an adsorbent to remove moisture from the crude triethyl phosphate. The gas then enters second pipeline 4 and passes through first filter 5 on second pipeline 4 to remove most particulate matter and residual particles from the catalyst and adsorbent. The filter is a high-density polyethylene filter with a pore size of 1 μm. The filtered material enters light components removal tower 11. The top temperature of tower 11 is 60°C, the top pressure is 2 kPa, the reflux ratio is 8, 7°C water is used as the refrigerant, and 160°C thermal 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 a de-weighting tower 12 through a third pipeline 6. The top temperature of the de-weighting tower 12 is 120°C, the top pressure is 1 kPa, and the reflux ratio is 8. 7°C water is used as the refrigerant, and 160°C thermal oil is used as the heat medium. Heavy components such as diethyl chlorophosphate and most metal ions are removed, and high-purity triethyl phosphate product is produced from the top of the tower. The high-purity triethyl phosphate product enters a product tank 8 through a fourth pipeline 7 at a temperature of 30°C and is pressurized with helium at a pressure of 0.1 MPa. A gear pump is used to transport the material in the product tank 8 to a second filter 10 on a fifth pipeline 13. Second filter 10 uses a high-density polyethylene filter with a pore size of 1 μm to remove particulate impurities and ensure long-term stability of the product particle index. The filtered high-purity triethyl phosphate can be directly refilled 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 the reaction rectification column 1 in a molar ratio of 1:4, the reaction rectification is carried out with anhydrous ZnCl2 of regular packing as catalyst, the operating temperature of the reaction rectification column 1 is 0℃, the operating pressure is 9kPa, the number of plates of the rectification section is 5, the number of plates of the reaction section is 40, and the number of plates of the stripping section is 30, the reactants are subjected to catalytic reaction and preliminary separation, most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reaction rectification column 1, and the product triethyl phosphate crude product is collected from the bottom of the column.

[0043] Step S2. The triethyl phosphate crude product collected from the bottom of the reaction rectification column 1 is passed through the first pipeline 2 into the adsorption column 3, the adsorption column 3 uses zeolite molecular sieve as adsorbent to remove water in the triethyl phosphate crude product. Then the gas 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, 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-removing column 11, the light-removing column 11 has a top temperature of 30℃, a top pressure of 10kPa, a reflux ratio of 10, uses 7℃ water as coolant, and uses 160℃ heat conducting oil as heating medium to remove light components such as hydrogen chloride, ethanol, diethyl phosphate, etc.

[0044] Step S3. The gas after light removal is passed through the third pipeline 6 into the heavy-removing column 12, the heavy-removing column 12 has a top temperature of 90℃, a top pressure of 9kPa, a reflux ratio of 10, uses 7℃ water as coolant, and uses 160℃ heat conducting oil as heating medium to remove heavy components such as diethyl chlorophosphate and most of the metal ions, and the high-purity triethyl phosphate product is collected at the top. The high-purity triethyl phosphate product is passed through the fourth pipeline 7 into the product tank 8, the temperature is 5℃, and the product tank 8 is pressurized with helium gas, 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 a pore size of 0.1 μm to remove particulate impurities and ensure long-term stability of the product particulate index. The filtered high-purity triethyl phosphate can be directly filled with the product or returned to the product tank 8.

[0045] Example 4

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

[0047] Step S1. Procured industrial-grade phosphorus oxychloride and ethanol are passed through a reactive distillation tower 1 in a molar ratio of 1:5. The reactive distillation uses anhydrous TiCl4 with structured packing as a catalyst. The operating temperature of the reactive 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. Most of the ethanol, hydrogen chloride and other light components are collected from the impurity gas outlet of the reactive distillation tower 1, and the crude product triethyl phosphate is collected from the bottom of the tower.

[0048] Step S2: The crude triethyl phosphate collected at the bottom of reactive distillation tower 1 enters adsorption tower 3 via first pipeline 2. Adsorption tower 3 uses calcium chloride as an adsorbent to remove moisture from the crude triethyl phosphate. The gas then enters second pipeline 4 and passes through a second filter 10 on second pipeline 4 to remove most particulate matter and residual particles from the catalyst and adsorbent. The filter is a high-density polyethylene filter with a pore size of 2μm. The filtered material enters light components removal tower 11. The top temperature of 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 thermal 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, and the reflux ratio is 5. 7°C water is used as the refrigerant, and 160°C thermal oil is used as the heat medium. Heavy components such as diethyl chlorophosphate and most metal ions are removed, 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 at a temperature of 25°C and is pressurized with helium to a pressure of 0.09 MPa. 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 a pore size of 2μm to remove particulate impurities and ensure the long-term stability of the product particle index. The filtered high-purity triethyl phosphate can be directly refilled 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 particulate matter index (≥0.2 μm) is not higher than 10 p / ml, which can meet production requirements.

[0052] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution range of the present application, can make some more changes or modifications to the equivalent embodiments of the equivalent changes, as long as it does not deviate from the technical solution content of the present application. Any modification, equivalent change and modification made to the above embodiments according to the technical essence 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 light-removal tower (11), a heavy-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 pipe (2), the top of the adsorption tower (3) is connected to the light-removal tower (11) through a second pipe (4), the bottom of the light-removal tower (11) is connected to the heavy-removal tower (12) through a third pipe (6), and the top of the heavy-removal tower (12) is connected to the product tank (8) through a fourth pipe (7); the bottom of the product tank (8) is connected to the side through a fifth pipe (13), and the fifth pipe (13) is provided with a second filter (10) and a liquid delivery pump (9); the first pipe (2) is provided with a first filter (5); 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; the bottom of the heavy component removal tower (12) is provided with a heavy component extraction outlet; In the reactive distillation tower (1), any one of the structured packings anhydrous MgCl2, anhydrous CuCl2, anhydrous ZnCl2 and anhydrous TiCl4 is used as a catalyst; The adsorption tower (3) is used to remove moisture from crude triethyl phosphate.

2. A device for preparing electronic-grade triethyl phosphate according to claim 1, characterized in that, The reaction 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.

3. 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 both have pore sizes of 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.

4. A method for preparing electronic-grade triethyl phosphate, based on a device for preparing electronic-grade triethyl phosphate according to any one of claims 1 to 3, 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: The triethyl phosphate obtained by the primary distillation is subjected to secondary distillation to remove heavy components, and then subjected to secondary filtration to finally obtain electronic grade triethyl phosphate.

5. A method for preparing electronic-grade triethyl phosphate according to claim 4, wherein In step S1, the purity of ethanol and phosphorus oxychloride are both industrial grade, the molar ratio of ethanol to phosphorus oxychloride is (1-5):1, and the water content of ethanol is 0-0.5%.

6. A method for preparing electronic-grade triethyl phosphate according to claim 4, 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 the drying in the step S2.

7. A method for preparing electronic-grade triethyl phosphate according to claim 4, characterized in that, In 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 step 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.

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