Method for producing high-purity electronic-grade isopropanol by using industrial-grade isopropanol

Abstract

The invention relates to a method for producing high-purity electronic-grade isopropanol by utilizing industrial-grade isopropanol, which comprises the following steps: enabling the industrial-grade isopropanol to sequentially pass through a first separator, a micro-filter, an anion and cation remover, a second separator and a nano-filter to obtain the high-purity electronic-grade isopropanol, wherein the first separator comprises a first light component removal tower and a first heavy component removal tower which are arranged in series, and the second separator comprises a second light component removal tower and a second heavy component removal tower which are arranged in series. Compared with the prior art, the method disclosed by the invention has the advantages of high product purity, high process yield, low impurity content, strong process continuity and the like, and the produced electronic-grade isopropanol product meets SEMI C12 and above standards, so that the method has relatively strong industrial production and application prospects of the high-purity electronic-grade isopropanol.

Description

Technical Field

[0001] The invention belongs to the technical field of organic purification and relates to a method for producing high-purity electronic-grade isopropanol by utilizing industrial-grade isopropanol. Background Art

[0002] Electronic grade isopropyl alcohol is mainly used in the electronic cleaning industry and can be used as a surface cleaning agent for chips. Its cleanliness and purity have an important impact on the yield, electrical performance and reliability of integrated circuits. In recent years, with the transformation and upgrading of my country's semiconductor industry, higher requirements have been placed on the product indicators of high-purity isopropyl alcohol that matches it. It is urgent to develop independent production technology for high-purity electronic grade isopropyl alcohol that meets SEMI C12 and above standards.

[0003] High-purity isopropanol is usually purified from industrial-grade isopropanol as raw material, and one of the difficulties is to remove water at low cost. Since isopropanol can form binary azeotropes with water, conventional distillation means are difficult to separate. Chinese patent literature CN102898275A discloses a continuous preparation method of high-purity isopropanol, which uses industrial-grade isopropanol as raw material, adopts 3A type molecular sieve and acrylic resin to remove the impurity water in the isopropanol raw material, and the water content in the prepared isopropanol is less than 20ppm. However, the method has a complex flow, and the process details are not mentioned and the device has high energy consumption. Chinese patent literature CN107365246A adopts the means of adsorption to remove water in the isopropanol raw material, specifically using one or more of activated alumina, activated carbon, silica gel and molecular sieve as adsorbent, to prepare isopropanol with a water content less than 50ppm. Chinese patent document CN102942447B discloses a method for refining electronic-grade isopropanol recovery liquid, specifically using anhydrous calcium chloride and calcium oxide as dehydrating agents to remove water from isopropanol, and the water content of the isopropanol product is less than 500ppm. However, the dehydrating agent used in this method consumes a large amount and is not easy to regenerate. Chinese patent document CN102531836A discloses a method for removing water from isopropanol by extractive distillation. Specifically, at least one of acetate and propionate is mixed with at least one of polar organic solvents ethylene glycol and propylene glycol as a salt extractant, and extractive distillation is performed to separate isopropanol and water under the conditions of a top temperature of 80-85°C and a bottom temperature of 130-135°C. However, the amount of extractant used in this method is large, and the introduction of inorganic salts has a corrosive effect on the production equipment. The second difficulty is that most existing patents cannot produce high-purity electronic-grade isopropanol that meets SEMI C12 and above standards, and lack effective and feasible control means for important indicators of the process flow, such as product yield and device energy consumption. Chinese patent document CN103848718A discloses a method for preparing electronic grade isopropyl alcohol using ion exchange fiber and microporous membrane coupling column. Specifically, anion and cation exchange fibers treated with hydrochloric acid, sodium hydroxide and ultra-high purity water are used as adsorbents; the pore size is 0.05-0.5μm, and the material is a microporous membrane of polytetrafluoroethylene, polyvinylidene fluoride or polyethersulfone. However, the purity of isopropyl alcohol prepared by this method can only reach 99.95%, and the water content is 200ppm, which cannot meet SEMI C12 and above standards. Chinese patent document CN114870420A discloses a method and device for continuous production of high-purity electronic grade isopropyl alcohol. Specifically, the method uses industrial grade isopropyl alcohol as a raw material, and prepares high-purity electronic grade isopropyl alcohol through a device composed of a dehydrator, a microfilter, an anion and cation remover, a distillation tower or a bulkhead tower, a nanofilter and other units. This method can prepare high-purity electronic grade isopropyl alcohol products that meet SEMI C12 and above standards. However, this method does not mention effective means to control the yield of isopropanol in the process flow, and its industrial feasibility remains to be verified. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing high-purity electronic grade isopropyl alcohol by utilizing technical grade isopropyl alcohol.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol comprises:

[0007] The industrial-grade isopropyl alcohol is sequentially passed through a first separator, a microfilter, an anion and cation remover, a second separator, and a nanofilter to obtain high-purity electronic-grade isopropyl alcohol;

[0008] Wherein, the first separator comprises a first light-removing tower and a first heavy-removing tower arranged in series, and the second separator comprises a second light-removing tower and a second heavy-removing tower arranged in series.

[0009] The first separator adopts a conventional distillation column series, the purpose is to remove most of the water and organic impurities in the industrial-grade isopropyl alcohol raw material; the microfilter and nanofilter are used to remove solid particles in the industrial-grade isopropyl alcohol raw material, and finally obtain a high-purity isopropyl alcohol with a purity of 99.99wt%, a water content of less than 50ppm, a metal ion content of less than 100ppt, and a particle size greater than 0.2μm (micrometer) and no more than 200 solid particles / mL. It is possible to produce high-purity electronic-grade isopropyl alcohol products that meet SEMIC12 and above standards from industrial-grade isopropyl alcohol raw materials, thereby meeting the needs of semiconductor and other industries for high-purity electronic-grade isopropyl alcohol.

[0010] As a preferred technical solution, the first light-removal tower and the first heavy-removal tower are made of polished stainless steel, and the inner lining material of the second light-removal tower and the second heavy-removal tower is polytetrafluoroethylene.

[0011] Furthermore, the bottom extraction end of the first light-removing tower is connected to the feed end of the first heavy-removing tower, and the top extraction end of the first heavy-removing tower is connected to the feed end of the microfilter;

[0012] The bottom extraction end of the second light-removing tower is connected to the feed end of the second heavy-removing tower, and the top extraction end of the second heavy-removing tower is connected to the inlet end of the nanofilter.

[0013] Furthermore, the first deweighting tower is an extractive distillation tower, and the extractant used is a mixture of one or more ionic liquids. The cations in the ionic liquid used are selected from one or more of imidazolium cations, pyridinium cations, quinoline cations or quaternary ammonium salt cations, and the anions are selected from one or more of halogen ions, acetate ions, tetrafluoroborate ions, hexafluorophosphate ions or phosphate ester ions.

[0014] Furthermore, the extractant is 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0015] The first de-weighting tower can be prepared by conventional distillation or extractive distillation. The extractive distillation using ionic liquid as an extractant can break the isopropanol-water azeotropic system in the raw material, while separating out isopropanol and reducing the loss of isopropanol at the bottom of the tower, thereby improving the purity and yield of isopropanol in the first de-weighting tower.

[0016] Specifically, the present invention utilizes ionic liquid as an extractant to break the isopropanol-water azeotropic system, thereby improving the yield and purity of isopropanol. Considering the isopropanol-water azeotropic system, after the industrial-grade isopropanol raw material containing water enters the first deweighting tower, part of the isopropanol will be lost from the bottom of the tower due to the isopropanol-water azeotropic system. At the same time, part of the water will also be entrained in the isopropanol extracted from the top of the tower. As a new type of green solvent, ionic liquid is almost non-volatile, easy to recycle, and has excellent chemical stability and thermal stability. Using ionic liquid as an extractant can break the azeotropic system of isopropanol-water, better remove water from isopropanol, and reduce the loss of isopropanol.

[0017] Furthermore, the number of theoretical plates of the extractive distillation tower is 10-50, the operating pressure is normal pressure, the tower top temperature is 50-100° C., and the reflux ratio is 1-2.

[0018] If the first deweighting tower is a conventional distillation tower, the number of theoretical plates is 10-50, the operating pressure is normal pressure, the tower top temperature is 50-100° C., and the reflux ratio is 1-5.

[0019] Furthermore, the extraction end of the bottom of the first de-weighting tower is also connected to an extractant regeneration device, and the extractant regeneration device is used to recover the extractant and transport it to the extractant inlet end of the first de-weighting tower.

[0020] Furthermore, the extractant regeneration device is a flash tank, the operating pressure is normal pressure or negative pressure, and the operating temperature is 60-250°C.

[0021] Furthermore, the filter membranes in the microfilter and nanofilter are selected from one or more of polytetrafluoroethylene, polyimide, polyamide, polyvinylidene fluoride membrane (PVDF) or polyethersulfone membrane.

[0022] Furthermore, in the anion and cation remover, the ion exchange medium used is selected from one or more of sulfonic acid styrene resin, quaternary amino styrene resin, sulfonated polyether sulfone resin or perfluorosulfonic acid resin.

[0023] Furthermore, the top produced liquid of the second light-removing tower and the bottom produced liquid of the second heavy-removing tower are mixed and returned to the first light-removing tower for feeding.

[0024] The loss of isopropyl alcohol in the overall process is reduced by adopting a circulation design, thereby increasing the yield of isopropyl alcohol. Considering that the waste liquid extracted from the top of the second light removal tower and the waste liquid extracted from the bottom of the second heavy removal tower in the second separator are rich in isopropyl alcohol, the two streams are mixed and recycled as raw materials.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] 1) The present invention uses industrial-grade isopropyl alcohol as a raw material, and its isopropyl alcohol purity is 97.5wt%. First, most of the water and organic impurities in the raw material are removed by a first separator, and then the solid large particles in the isopropyl alcohol are removed by a microfilter. The isopropyl alcohol after microfiltration continues to remove most of the anions and cations by an anion and cation remover. Subsequently, the isopropyl alcohol enters the next-stage separator for removing the moisture generated in the ion exchange process and further removing the organic impurities in the raw material. Finally, the isopropyl alcohol extracted from the separator passes through a nanofilter to remove the solid microparticles in the isopropyl alcohol to obtain a final product, which has the advantages of high product purity, high process yield, low impurity content, strong process continuity, etc. The electronic-grade isopropyl alcohol product produced meets SEMI C12 and above standards, and therefore has a strong industrial production and application prospect of high-purity electronic-grade isopropyl alcohol.

[0027] 2) The present invention adds an extractant regeneration device after the extractive distillation tower, recovers the extractant by flash evaporation, and returns it to the extractive distillation tower for recycling, thereby effectively improving the utilization rate of the extractant and reducing the production cost.

[0028] 3) The present invention adopts a circulation design to reduce the loss of isopropyl alcohol in the overall process flow, thereby improving the yield of isopropyl alcohol.

[0029] 4) The present invention utilizes ionic liquid as an extractant to break the isopropanol-water azeotropic system, thereby improving the yield and purity of isopropanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a process flow chart of a method for producing high-purity isopropanol in Example 1;

[0031] Figure 2 is a process flow chart of a method for producing high-purity isopropanol in Example 2;

[0032] Figure 3 This is a process flow chart of a method for producing high-purity isopropanol in Comparative Example 1;

[0033] Figure 4 This is a process flow chart of a method for producing high-purity isopropanol in Comparative Example 2;

[0034] Description of the markings in the figure:

[0035] 1-industrial grade isopropanol raw material; 2-first light-removing tower; 3-light component of first light-removing tower; 4-heavy component of first light-removing tower; 5-first heavy-removing tower; 6-light component of first heavy-removing tower; 7-heavy component and extractant mixture; 8-extractant regeneration device; 9-removed heavy component of first heavy-removing tower; 10-regenerated high-purity extractant; 11-microfilter; 12-isopropanol after microfiltration; 13-anion and cation remover; 14-isopropanol after anion and cation removal; 15-second light-removing tower; 16-light component of second light-removing tower; 17-heavy component of second light-removing tower; 18-second heavy-removing tower; 19-light component of second heavy-removing tower; 20-heavy component of second heavy-removing tower; 21-nanofilter; 22-high-purity isopropanol product; 23-circulating isopropanol. DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1 As shown, a method for producing high-purity electronic grade isopropyl alcohol comprises a first separator, a microfilter 11, an anion and cation remover 13, a second separator, and a nanofilter 21 connected in sequence. The method is used to produce a high-purity isopropyl alcohol product having a purity of 99.99 wt %, a water content of less than 50 ppm, a metal ion content of less than 100 ppt, and a particle size greater than 0.2 μm and no more than 200 solid particles / mL.

[0038] The present invention provides a method for producing high-purity electronic-grade isopropyl alcohol with high product purity, high process yield, strong process continuity and strong industrialization prospects. It can realize the production of high-purity isopropyl alcohol products that meet SEMI C12 and above standards from industrial-grade isopropyl alcohol raw materials, thereby meeting the demand for high-purity electronic-grade isopropyl alcohol in the semiconductor and other industries.

[0039] Industrial-grade isopropanol raw material 1 enters the first light-removing tower 2 and the first heavy-removing tower 5 of the first separator to remove most of the water and organic impurities in the raw material. The first separator can use a polished stainless steel conventional distillation tower series. The isopropanol extracted from the first separator enters the microfilter 11 to remove solid particles with a particle size of more than 0.2 μm in the isopropanol. The microfilter 11 can use a polytetrafluoroethylene membrane, polyimide membrane, polyamide membrane, polyvinylidene fluoride membrane, polyethersulfone membrane or other membranes of equal properties with a pore size of 0.1-0.2 μm. One or more. The isopropanol after microfiltration enters the anion and cation remover 13 to remove anionic and cationic impurities. The ion exchange medium of the anion and cation remover 13 can be one or more of sulfonic acid styrene resin, quaternary amino styrene resin, sulfonated polyethersulfone resin, and perfluorosulfonic acid resin. Isopropanol is further removed from water and organic impurities by the second light-removing tower 15 and the second heavy-removing tower 18 of the second separator. The second separator can use a conventional distillation tower series lined with polytetrafluoroethylene to avoid the introduction of impurity metal ions. Finally, the isopropanol is passed through a nanofilter 21 to remove solid particles larger than 50 nm (nanometers). The nanofilter 21 may be a polytetrafluoroethylene membrane, a polyimide membrane, a polyamide membrane, a polyvinylidene fluoride membrane, a polyethersulfone membrane or other membranes of equivalent properties with a pore size of 10-50 nm. Finally, a high-purity isopropanol product with a purity of 99.99 wt %, a water content of less than 50 ppm, a metal ion content of less than 100 ppt, and a solid particle size greater than 0.2 μm with no more than 200 particles / mL is obtained.

[0040] At the same time, the top produced liquid of the second light-removing tower 15 of the second separator and the bottom produced liquid of the second heavy-removing tower 18 are mixed, subjected to heat exchange, and enter the first light-removing tower 2 of the first separator as raw materials for recycling.

[0041] The isopropyl alcohol raw material of the present invention is industrial grade isopropyl alcohol, and the specific raw material composition is shown in Table 1.

[0042] Table 1 Industrial grade isopropanol raw material composition

[0043]

[0044] Table 2 Product indicators obtained by the present invention

[0045]

[0046]

[0047] The above table is to illustrate the components contained in the industrial-grade isopropyl alcohol raw material, and does not limit the applicability of the invention. The purity of the isopropyl alcohol product produced by the patent invention method can reach 99.99wt%, the water content is less than 50ppm, the metal ion content is less than 100ppt, and the solid particles with a particle size greater than 0.2μm do not exceed 200 / mL, meeting SEMI C12 and above standards. At the same time, the yield of the isopropyl alcohol product in the process can reach 69%.

[0048] The following embodiments are implemented based on the above technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0049] Embodiment 1:

[0050] refer to Figure 1 , the industrial-grade isopropanol raw material 1 enters the first separator, which uses two conventional distillation towers made of polished stainless steel, namely the first light-removal tower 2 and the first heavy-removal tower 5. The first light-removal tower 2 uses conventional distillation to remove light component impurities, namely the light component 3 of the first light-removal tower, the tower top pressure is 0.1MPa, the tower top temperature is 80℃, the tower bottom temperature is 85℃, the theoretical plate number is 30, the feed position is the 10th tower plate, the reflux ratio is 5, and the tower bottom is produced after most of the light components are removed. Isopropanol, namely the heavy component 4 of the first light-removal tower. The first heavy-removal tower 5 uses extractive distillation, and the extractant is the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM] BF 4 , the tower top pressure is 0.1MPa, the tower top temperature is 83℃, the tower bottom temperature is 87℃, the theoretical plate number is 30, the feed position is the 10th tower plate, and the reflux ratio is 1. [EMIM]BF 4 As an extractant, it is added from the second plate of the second de-weighting tower 5. The isopropanol with most of the water and organic impurities removed is taken out from the top of the tower, i.e., the light component 6 of the first de-weighting tower. The bottom of the tower contains isopropanol, [EMIM]BF 4, water and other organic impurities, that is, a mixture of heavy components and extractant 7. The mixed solution extracted from the bottom of the tower enters the extractant regeneration device 8. The extractant regeneration device 8 uses a flash tank with an operating pressure of 0.07Mpa and an operating temperature of 110°C. The regenerated high-purity extractant 10 returns to the first de-weighting tower 5 for recycling. After removing most of the water and organic impurities, the isopropanol extracted from the first de-weighting tower 5 enters the microfilter 11 to remove solid particles with a particle size of more than 0.2μm. The filter membrane of the microfilter 11 uses a polytetrafluoroethylene membrane with a pore size of 0.2μm and a uniformity coefficient of 1.1. The isopropanol 12 after microfiltration enters the anion and cation remover 13 to remove anion and cation impurities, and then obtains isopropanol 14 after the anion and cation are removed, and enters the second separator to further remove water and organic impurities. The second separator uses two conventional distillation towers lined with polytetrafluoroethylene, namely, the second light-removing tower 15 and the second heavy-removing tower 18. The top pressure of the second light-removing tower 15 is 0.1 MPa, the top temperature is 80°C, the bottom temperature is 84°C, the theoretical plate number is 30, the feed position is the 10th tower plate, the reflux ratio is 9, and the isopropanol after further removal of light components from the bottom of the tower, namely, the heavy component 17 of the second light-removing tower, is sent to the second heavy-removing tower 18. The top pressure of the second heavy-removing tower 18 is 0.1 MPa. , the tower top temperature is 82°C, the tower bottom temperature is 84°C, the theoretical plate number is 30, the feed position is the 10th tower plate, the reflux ratio is 10, and the isopropanol after further removal of the heavy components is taken out from the tower top, which is recorded as the light component 19 of the second deheaving tower. The solid particles with a particle size of more than 10 nm are removed by the nanofilter 21. The filter membrane of the nanofilter 21 can adopt a polyvinylidene fluoride membrane with a pore size of 10 nm and a uniformity coefficient of 1.1. After nanofiltration, a high-purity isopropanol product 22 is obtained. The specific indicators are shown in Table 2.

[0051] At the same time, the isopropanol-rich mixed liquid extracted from the top of the second light-removing tower 15 of the second separator, i.e., the second light-removing tower light component 16, and the isopropanol-rich mixed liquid extracted from the bottom of the second heavy-removing tower 18, i.e., the second heavy-removing tower heavy component 20, are mixed and used as a raw material, i.e., recycled isopropanol 23, to enter the first light-removing tower 2 of the first separator for recycling.

[0052] Embodiment 2:

[0053] refer to Figure 2, the industrial-grade isopropanol raw material 1 enters the first separator, which uses two conventional distillation towers made of polished stainless steel, namely the first light-removing tower 2 and the first heavy-removing tower 5. The top pressure of the first light-removing tower 2 is 0.1MPa, the top temperature is 80°C, the bottom temperature is 84°C, the theoretical plate number is 30, the feed position is the 10th tower plate, and the reflux ratio is 5. The top pressure of the first heavy-removing tower 5 is 0.1MPa, the top temperature is 81°C, the bottom temperature is 86°C, the theoretical plate number is 30, the feed position is the 10th tower plate, and the reflux ratio is 3. After removing most of the water and organic impurities, the isopropanol extracted from the first heavy-removing tower 5 enters the microfilter 11 to remove solid particles with a particle size of more than 0.2μm. The filter membrane of the microfilter 11 adopts a polytetrafluoroethylene membrane with a pore size of 0.2μm and a uniformity coefficient of 1.1. The isopropanol after microfiltration enters the anion and cation remover 13 to remove anion and cation impurities, and then enters the second separator to further remove water and organic impurities. The second separator uses two conventional distillation towers lined with polytetrafluoroethylene, namely the second light removal tower 15 and the second heavy removal tower 18. The top pressure of the second light removal tower 15 is 0.1MPa, the top temperature is 81°C, the bottom temperature is 84°C, the theoretical plate number is 30, the feed position is the 10th tower plate, and the reflux ratio is 9. The top pressure of the second heavy removal tower 18 is 0.1MPa, the top temperature is 82°C, the bottom temperature is 84°C, the theoretical plate number is 30, the feed position is the 10th tower plate, and the reflux ratio is 13. The isopropanol product obtained from the top of the second deweighting tower 18 is passed through a nanofilter 21 to remove solid particles with a particle size of more than 10 nm. The filter membrane of the nanofilter 21 can be a polyvinylidene fluoride membrane with a pore size of 10 nm and a uniformity coefficient of 1.1. After nanofiltration, a high-purity isopropanol product is obtained. The specific indicators are shown in Table 2.

[0054] At the same time, the top produced liquid of the second light-removing tower 15 of the second separator and the bottom produced liquid of the second heavy-removing tower 18 are mixed and enter the first light-removing tower 2 of the first separator as raw materials for recycling.

[0055] Comparative Example 1:

[0056] refer to Figure 3 Compared with Example 1, the second separator of the second light removal tower 15 and the waste liquid circulation device of the second heavy removal tower 18 are not provided, and the rest are the same as Example 1. The product indicators are shown in Table 2.

[0057] Comparative Example 2:

[0058] refer to Figure 4 Compared with Example 2, the second separator of the second light removal tower 15 and the waste liquid circulation device of the second heavy removal tower 18 are not provided, and the rest are the same as Example 2. The product indicators are shown in Table 2.

[0059] Test example:

[0060] The components in the isopropanol of Example 1-2 and Comparative Example 1-2 were tested for content, and the testing instruments were: Agilent ICP-MS / MS 8900 was used for product metal elements and elements such as boron, silicon, and arsenic, Swiss Metrohm 940 ion chromatograph was used for anions, Agilent GC-MS gas chromatograph was used for raw material and product impurity content, 851 Coulometric Karl Fischer titrator was used for water content, and RION-KS-19AF was used for particle size analyzer. The results are shown in Table 1-2.

[0061] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol, It is characterized in that include: The industrial-grade isopropyl alcohol is sequentially passed through a first separator, a microfilter (11), an anion and cation remover (13), a second separator, and a nanofilter (21) to obtain high-purity electronic-grade isopropyl alcohol; The first separator comprises a first light-removing tower (2) and a first heavy-removing tower (5) arranged in series, and the second separator comprises a second light-removing tower (15) and a second heavy-removing tower (18) arranged in series.

2. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 1, It is characterized in that The bottom extraction end of the first light-removing tower (2) is connected to the feed end of the first heavy-removing tower (5), and the top extraction end of the first heavy-removing tower (5) is connected to the feed end of the microfilter (11); The bottom outlet of the second light-removing tower (15) is connected to the feed end of the second heavy-removing tower (18), and the top outlet of the second heavy-removing tower (18) is connected to the inlet end of the nanofilter (21).

3. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 1, It is characterized in that The first deweighting tower (5) is an extractive distillation tower, and the extractant used is a mixed solution of one or more ionic liquids, the cations in the ionic liquid used are selected from one or more of imidazolium cations, pyridinium cations, quinoline cations or quaternary ammonium salt cations, and the anions are selected from one or more of halogen ions, acetate ions, tetrafluoroborate ions, hexafluorophosphate ions or phosphate ester ions.

4. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 3, It is characterized in that The extractant is 1-ethyl-3-methylimidazolium tetrafluoroborate.

5. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 3, It is characterized in that The number of theoretical plates of the extractive distillation tower is 10-50, the operating pressure is normal pressure, the tower top temperature is 50-100° C., and the reflux ratio is 1-2.

6. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 3, It is characterized in that The bottom extraction end of the first de-weighting tower (5) is also connected to an extractant regeneration device (8), and the extractant regeneration device (8) is used to recover the extractant and transport it to the extractant inlet end of the first de-weighting tower (5).

7. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 6, It is characterized in that The extractant regeneration device (8) is a flash tank, the operating pressure is normal pressure or negative pressure, and the operating temperature is 60-250°C.

8. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 1, It is characterized in that The filter membranes in the microfilter (11) and the nanofilter (21) are respectively selected from one or more of polytetrafluoroethylene, polyimide, polyamide, polyvinylidene fluoride membrane (PVDF) or polyethersulfone membrane.

9. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 1, It is characterized in that In the anion and cation remover (13), the ion exchange medium used is selected from one or more of sulfonic acid styrene resin, quaternary amino styrene resin, sulfonated polyether sulfone resin or perfluorosulfonic acid resin.

10. The method for producing high-purity electronic-grade isopropyl alcohol using industrial-grade isopropyl alcohol according to claim 1, It is characterized in that The top produced liquid of the second light-removing tower (15) is mixed with the bottom produced liquid of the second heavy-removing tower (18) and returned to the first light-removing tower (2) for feeding.

Images