Industrial-grade isopropanol purification method

Abstract

The invention relates to the field of preparation of high-end wet electronic chemicals for integrated circuits, in particular to an industrial-grade isopropanol purification method. The method comprises the following steps: carrying out dehydration and light component removal on industrial-grade isopropanol to obtain a light liquid phase and a heavy liquid phase; the light liquid phase is subjected to flash evaporation treatment to obtain a second liquid phase, and the second liquid phase is subjected to catalytic hydrogenation and then returns for light component removal; and the heavy liquid phase is subjected to heavy component removal. According to the invention, flash evaporation and catalytic hydrogenation are carried out on the dehydrated material sent into the light component removal tower, so that the recovery rate of the purified isopropanol product is greatly improved under the condition of ensuring the technical indexes such as product purity and water content.

Description

Technical Field

[0001] The invention relates to the field of preparation of high-end wet electronic chemicals for integrated circuits, and in particular to a method for purifying industrial-grade isopropyl alcohol. Background Art

[0002] With the rapid development of my country's integrated circuit industry, the demand and requirements for ultra-clean and high-purity reagents have further increased. In the entire integrated circuit manufacturing industry, ultra-clean and high-purity reagents are mainly used for chip cleaning and drying, and the quality of the product has an important impact on the chip yield.

[0003] Ultra-clean high-purity isopropyl alcohol is the most widely used organic wet electronic chemical, often used as the last cleaning step for chips. Therefore, there are extremely strict requirements for its product quality. In addition to product purity, organic impurities and water content, there are also very strict requirements for the residual anions, cations and particulate matter. And with the further breakthroughs in chip manufacturing processes, higher requirements are also placed on the product quality of ultra-clean high-purity isopropyl alcohol.

[0004] There are some documents and patent reports on the preparation process of ultra-clean high-purity isopropyl alcohol. For example, CN 114870420A reports a method for producing high-purity electronic-grade isopropyl alcohol including a dehydration processor, a microfilter, an anion and cation remover, a distillation tower and a nanofiltration. However, the product of this process method can only meet the SEMI G4 standard, and the recovery rate of electronic-grade isopropyl alcohol is low due to the large number of distillation steps in the process. For example, CN 101362675B reports a method for preparing ultra-clean high-purity isopropyl alcohol using industrial-grade isopropyl alcohol as a raw material, and the method adopts steps such as complexation, dehydration, microfiltration, distillation, and nanofiltration to finally obtain an ultra-clean high-purity isopropyl alcohol product. In the process, it is necessary to remove organic impurities by four-stage distillation. Similarly, CN 103613486A also reports a method for preparing ultra-clean high-purity isopropyl alcohol, in which multi-stage continuous distillation is used to remove organic impurities. The above preparation method has poor removal efficiency for organic impurities and seriously affects the single-pass yield of ultra-clean high-purity isopropanol, resulting in low production efficiency. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of poor removal efficiency of organic impurities in the prior art, which seriously affects the single-pass yield of ultra-clean high-purity isopropanol and low production efficiency, and to provide an industrial-grade isopropanol purification method, which has the characteristics of short process flow, high product recovery rate and good product quality.

[0006] In order to achieve the above object, the present invention provides an industrial-grade isopropanol purification method, which comprises: dehydrating the industrial-grade isopropanol and removing light to obtain a light liquid phase and a heavy liquid phase; flashing the light liquid phase to obtain a second liquid phase, and the second liquid phase is returned to the light phase after catalytic hydrogenation; and removing heavy liquid from the heavy liquid phase.

[0007] Through the above technical solution, the present invention has the following advantages:

[0008] The invention performs flash evaporation and catalytic hydrogenation on the material obtained by feeding the dehydration tower after dehydration, thereby greatly improving the recovery rate of the purified isopropanol product under the condition of ensuring technical indicators such as product purity and water content. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The present invention is a preferred embodiment of the industrial-grade isopropanol purification process flow chart.

[0010] Description of Reference Numerals

[0011] ①Pervaporation unit ②Light removal tower

[0012] ③Flash tank ④Catalytic hydrogenation unit

[0013] ⑤Degravity tower ⑥Deionization tower

[0014] ⑦ De-particle device 1. Industrial isopropyl alcohol

[0015] 2. Dehydrated product 3. Light removal tower bottom liquid

[0016] 4. Light removal tower top liquid 5. Flash steam phase

[0017] 6. Flash liquid phase 7. Product after catalytic hydrogenation

[0018] 8. Degravity tower bottom liquid 9. Degravity tower top liquid

[0019] 10. Deionized products 11. Purified isopropanol products DETAILED DESCRIPTION

[0020] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0021] The invention provides an industrial-grade isopropanol purification method, which comprises: dehydrating the industrial-grade isopropanol and removing light to obtain a light liquid phase and a heavy liquid phase; flashing the light liquid phase to obtain a second liquid phase, and the second liquid phase is catalytically hydrogenated and then returned to the light phase for removal; and removing heavy liquid phase.

[0022] The invention performs flash evaporation and catalytic hydrogenation on the material obtained by feeding the dehydration tower after dehydration, thereby greatly improving the recovery rate of the purified isopropanol product under the condition of ensuring technical indicators such as product purity and water content.

[0023] According to a preferred embodiment of the present invention, the conditions of the flash treatment include: a pressure of 20-80 kPaA, and / or a controlled temperature of the flash liquid phase of 46.5-76.2°C.

[0024] According to a preferred embodiment of the present invention, the flash treatment conditions include: a pressure of 40-60 kPaA, and / or a controlled temperature of the flash liquid phase of 60.5-69.5° C. By adopting the above preferred scheme, the light components can be removed well and the recovery rate of isopropanol can be improved.

[0025] According to a preferred embodiment of the present invention, the catalyst for catalytic hydrogenation is a solid catalyst, preferably a copper-based catalyst. By adopting the above preferred embodiment, the residual acetone can be converted into isopropanol, thereby improving the purity of purified isopropanol.

[0026] According to a preferred embodiment of the present invention, the conditions for catalytic hydrogenation include: reaction pressure of 3-10 MPaA; and / or reaction temperature of 80°C-120°C; and / or space velocity of 0.2-0.8 h -1 , and / or the molar ratio of hydrogen to the second liquid phase (in terms of ketone compounds) is 2 to 10. By adopting the above preferred embodiment, the trace amount of acetone in the product after light removal can be converted into isopropanol, the content of acetone in the light removal tower can be reduced, and the purity of the purified isopropanol product can be improved.

[0027] According to a preferred embodiment of the present invention, the light removal conditions include: a pressure of 101-200 kPa; and / or a reflux ratio of 2-20; and / or a bottom operating temperature of 82.8°C-100.5°C.

[0028] According to a preferred embodiment of the present invention, the weight removal conditions include: a pressure of 101-200 kPa; and / or a reflux ratio of 0.2-5; and / or a tower top operating temperature of 82.5°C-100.2°C.

[0029] According to a preferred embodiment of the present invention, the method further comprises: after the heavy liquid phase is deweighted, deionizing and demicroparticleizing are performed in sequence to obtain purified isopropanol.

[0030] According to a preferred embodiment of the present invention, the deionization is carried out by ion exchange resin adsorption.

[0031] According to a preferred embodiment of the present invention, the ion exchange resin is a mixed resin comprising a hydrogen-type strongly acidic cation exchange resin and a hydroxide-type strongly basic anion exchange resin, and more preferably the mass ratio of the hydrogen-type strongly acidic cation exchange resin to the hydroxide-type strongly basic anion exchange resin is 3:1-1:3. By adopting the above preferred scheme, the residual trace anions and cations in the product can be efficiently removed.

[0032] According to a preferred embodiment of the present invention, the degranulation is carried out in the form of filtration.

[0033] According to a preferred embodiment of the present invention, the filtration preferably uses a filter element made of at least one of PFA, PTFE and PP. By adopting the above preferred solution, the particles in the isopropanol product can be removed well, and the technical requirement of particles with a size of ≥50nm ≤10 / ml can be achieved.

[0034] According to a preferred embodiment of the present invention, the filtration is carried out in a multi-stage series connection manner, preferably in a at least three-stage series connection manner. The present invention illustrates the advantages of the present invention by a four-stage series connection manner (with specifications of 200nm, 100nm, 50nm and 15nm, respectively, and the material is PFA filter element).

[0035] According to a preferred embodiment of the present invention, the dehydration is performed by molecular sieve adsorption and / or pervaporation.

[0036] According to a preferred embodiment of the present invention, the molecular sieve is at least one of type 3A molecular sieve, type 4A molecular sieve and type 5A molecular sieve.

[0037] According to a preferred embodiment of the present invention, the pervaporation uses a molecular sieve membrane, and the pervaporation operation preferably includes: an absolute pressure of 1 bar-8 bar. By adopting the above preferred scheme, the water in the isopropanol product can be removed to meet the technical requirement of water content ≤ 100 ppm.

[0038] According to a preferred embodiment of the present invention, the content of isopropanol in the industrial grade isopropanol is ≥ 98 wt %, preferably ≥ 99.5 wt %.

[0039] According to a preferred embodiment of the present invention, the industrial-grade isopropyl alcohol further contains at least one of water, methanol, ethanol, n-propanol, isopropyl ether, acetone, methyl ethyl ketone and isobutyl alcohol.

[0040] According to a preferred embodiment of the present invention, the second liquid phase is catalytically hydrogenated and then returned to the de-lightened material, which is mixed with the dehydrated material and then de-lightened together. By adopting the above preferred scheme, the recovery rate of the purified isopropanol product can be improved.

[0041] According to a preferred embodiment of the present invention, the purity of isopropyl alcohol in the product after purification of industrial-grade isopropyl alcohol is above 99.99%, and the water content is ≤100ppm. Preferably, the single metal ion in the product is ≤10ppt, and the particles with a diameter of ≥50nm are ≤10 / ml.

[0042] like Figure 1 As shown, the present invention provides an exemplary description of a preferred embodiment, and the illustrated device includes:

[0043] The discharge pipeline of the pervaporation device ① is connected with the feed pipeline of the lightness removal tower ②, the top discharge pipeline of the lightness removal tower ② is connected with the feed port of the flash tank ③, the liquid phase discharge port of the flash tank ③ is connected with the bottom feed port of the catalytic hydrogenation device ④, the top discharge port of the catalytic hydrogenation device ④ is connected with the feed pipeline of the lightness removal tower ②, the bottom discharge pipeline of the lightness removal tower ② is connected with the feed pipeline of the deweight removal tower ⑤, the top discharge pipeline of the deweight removal tower ⑤ is connected with the top feed port of the deionization tower ⑥, and the bottom of the deionization tower ⑥ is connected with the demicronization device ⑦.

[0044] The preparation process of isopropyl alcohol includes:

[0045] Industrial-grade isopropyl alcohol 1 enters a pervaporation device ①, and the product 2 after dehydration on the concentration side enters a lightness removal tower ②. The top liquid 4 of the lightness removal tower enters a flash tank ③ for flash evaporation, and the flash vapor phase 5 is discharged from the device. The flash vapor phase 6 is hydrogenated in a catalytic hydrogenation device ④ to obtain a catalytic hydrogenation product 7, which is returned to the lightness removal tower ② for feeding; the bottom liquid 3 of the lightness removal tower enters a heavy removal tower ⑤, and the top liquid 9 of the heavy removal tower passes through a deionizing tower ⑥ to obtain a deionized product 10. The deionized product 10 passes through a demicronizing device ⑦ to finally obtain a purified isopropyl alcohol product 11, and the bottom liquid 8 of the heavy removal tower is discharged from the device.

[0046] In the present invention, the "tower top, top part" refers to the "0-30%" part of the volume of each device from top to bottom; the "tower bottom, bottom part" refers to the "70-100%" part of the volume of each device from top to bottom.

[0047] The present invention will be described in detail below by way of examples. The reagents and raw materials used in the present invention are all commercially available.

[0048] In the present invention, the catalytic hydrogenation device of the embodiment is loaded with the same copper-based catalyst, the product purity is detected by HPLC, the water content is determined by Karl Fischer titrator, the metal ions are determined by ICP-MS, and the particle number is determined online by a particle counter.

[0049] Example 1

[0050] A batch of industrial-grade isopropanol, in which the purity of isopropanol is 99.5%, the water content is 475ppm, and the acetone content is 215ppm. First, pervaporation is used to remove the water in the industrial-grade isopropanol. The operating pressure (absolute pressure) of pervaporation is 6bar. The dehydrated product is subjected to light removal treatment. The operating pressure (absolute pressure) of light removal treatment is 125kPa, the reflux ratio is 10, and the operating temperature of the bottom of the tower is controlled to be 88.3℃. The top product of the light removal treatment is flash evaporated. The operating pressure (absolute pressure) of the flash evaporated is 50kPa, and the temperature of the flash evaporated liquid phase is controlled to be 65.4℃. The liquid phase after flash evaporated is catalytically hydrogenated. The operating pressure (absolute pressure) of catalytic hydrogenation (the catalyst is a copper-based catalyst, the same below) is 8MPa, the reaction temperature is controlled at 110℃, and the air velocity is 0.6h -1 , the molar ratio of hydrogen to the liquid phase after flash evaporation (in terms of ketone compounds) is 6. The hydrogenated product is re-treated with the dehydrated product. The tower bottom product after light removal is subjected to heavy removal. The operating pressure (absolute pressure) of the heavy removal treatment is 125kPa, the reflux ratio is 2, and the operating temperature of the tower top is controlled to be 87.4℃. The obtained tower top product is successively deionized (the mass ratio of hydrogen-type strong acid cation exchange resin and hydrogen-oxygen-type strong basic anion exchange resin is 1:1) and degranulated (using four-stage series connection with specifications of 200nm, 100nm, 50nm and 15nm, respectively, and the material is PFA filter element), and ultra-clean high-purity isopropyl alcohol is obtained.

[0051] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.998%, the water content is 45ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 89.3% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0052] Example 2

[0053] A batch of industrial-grade isopropanol, in which the purity of isopropanol is 99.5%, the water content is 475ppm, and the acetone content is 215ppm. First, pervaporation is used to remove the water in the industrial-grade isopropanol. The operating pressure (absolute pressure) of pervaporation is 2bar. The dehydrated product is subjected to light removal treatment. The operating pressure (absolute pressure) of light removal treatment is 150kPa, the reflux ratio is 10, and the operating temperature of the tower bottom is controlled to be 92.8℃. The top product of the tower after light removal treatment is flash evaporated. The operating pressure (absolute pressure) of the flash evaporated is 80kPa, and the temperature of the flash evaporated liquid phase is controlled to be 76.2℃. The liquid phase after flash evaporated is catalytically hydrogenated. The operating pressure (absolute pressure) of catalytic hydrogenation is 6MPa, the reaction temperature is controlled at 100℃, and the space velocity is 0.6h -1, the molar ratio of hydrogen to the liquid phase after flash evaporation (in terms of ketone compounds) is 6. The hydrogenated product is re-treated with the dehydrated product. The tower bottom product after light removal is subjected to heavy removal. The operating pressure (absolute pressure) of the heavy removal treatment is 150kPa, the reflux ratio is 2, and the operating temperature of the tower top is controlled to be 92.3℃. The obtained tower top product is successively deionized (the mass ratio of hydrogen-type strong acid cation exchange resin and hydrogen-oxygen-type strong basic anion exchange resin is 2:1) and de-particled (using four-stage series connection with specifications of 200nm, 100nm, 50nm and 15nm, respectively, and the material is PFA filter element), and ultra-clean high-purity isopropyl alcohol is obtained.

[0054] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.994%, the water content is 82ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 88.2% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0055] Example 3

[0056] A batch of industrial-grade isopropanol, in which the purity of isopropanol is 98.5%, the water content is 2500ppm, and the acetone content is 456ppm. First, pervaporation is used to remove the water in the industrial-grade isopropanol. The operating pressure (absolute pressure) of pervaporation is 6bar. The dehydrated product is subjected to light removal treatment. The operating pressure (absolute pressure) of light removal treatment is 200kPa, the reflux ratio is 2, and the operating temperature of the tower bottom is controlled to be 100.5℃. The top product of the tower after light removal treatment is flash evaporated. The operating pressure (absolute pressure) of the flash evaporated is 40kPa, and the temperature of the flash evaporated liquid phase is controlled to be 60.6℃. The liquid phase after flash evaporated is catalytically hydrogenated. The operating pressure (absolute pressure) of catalytic hydrogenation is 8MPa, the reaction temperature is controlled at 110℃, and the air velocity is 0.6h -1 , the molar ratio of hydrogen to the liquid phase after flash evaporation (in terms of ketone compounds) is 6. The hydrogenated product is re-treated with the dehydrated product. The tower bottom product after light removal is subjected to heavy removal. The operating pressure (absolute pressure) of the heavy removal treatment is 101kpa, the reflux ratio is 5, and the operating temperature of the tower top is controlled to be 82.5℃. The obtained tower top product is successively deionized (the mass ratio of hydrogen-type strong acid cation exchange resin and hydrogen-oxygen-type strong basic anion exchange resin is 1:2) and degranulated to obtain ultra-clean high-purity isopropyl alcohol.

[0057] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.997%, the water content is 95ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 89.0% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0058] Example 4

[0059] Same as Example 1, except that the operating pressure (absolute pressure) of the flash evaporation is 90 kPa, and the controlled temperature of the flash evaporation liquid phase is 79.1°C.

[0060] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.992%, the water content is 63ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 84.5% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0061] Example 5

[0062] Same as Example 1, except that the reaction temperature of the catalytic hydrogenation is controlled at 60°C.

[0063] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.990%, the water content is 48ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 85.9% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0064] Example 6

[0065] Same as Example 1, except that the operating pressure (absolute pressure) of the pervaporation is 0.5 bar.

[0066] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.996%, the water content is 98ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 85.3% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0067] Comparative Example 1

[0068] The same as Example 1, except that there is no flash unit, and the top product of the light removal treatment directly enters the catalytic hydrogenation device.

[0069] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.962%, the water content is 50ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 81.2% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0070] Comparative Example 2

[0071] The same as Example 1, except that it does not contain a catalytic hydrogenation unit, and the liquid phase after flash evaporation is directly returned to the light removal process.

[0072] It has been determined that the purity of the isopropyl alcohol in the ultra-clean high-purity isopropyl alcohol product is 99.981%, the water content is 48ppm, the single metal ion in the product is ≤10ppt, the particles (≥50nm) are ≤10 / ml, and the recovery rate of the ultra-clean high-purity isopropyl alcohol is 79.5% (recovery rate = (output of ultra-clean high-purity isopropyl alcohol / feed amount of industrial-grade isopropyl alcohol)*100%).

[0073] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for purifying industrial-grade isopropanol, characterized in that: The method comprises: dehydrating industrial-grade isopropanol and removing light to obtain a light liquid phase and a heavy liquid phase; The light liquid phase is flashed to obtain a second liquid phase, and the second liquid phase is catalytically hydrogenated and then returned to remove light liquid; The heavy liquid phase is deweighted.

2. The purification method according to claim 1, wherein The flash treatment conditions include: a pressure of 20-80 kPaA, and / or a controlled temperature of the flash liquid phase of 46.5-76.2°C; preferably The pressure is 40-60 kPaA, and / or the controlled temperature of the flash liquid phase is 60.5-69.5°C.

3. The purification method according to claim 1 or 2, wherein: The catalyst for catalytic hydrogenation is a solid catalyst, preferably a copper-based catalyst; and / or The conditions of the catalytic hydrogenation include: a reaction pressure of 3-10 MPaA; and / or a reaction temperature of 80°C-120°C; and / or a space velocity of 0.2-0.8 h -1 , and / or the hydrogen / second liquid phase molar ratio is 2-10.

4. The purification method according to any one of claims 1 to 3, wherein The conditions for removing light include: pressure of 101-200 kPa; and / or reflux ratio of 2-20; and / or tower bottom operating temperature of 82.8°C-100.5°C; and / or The conditions for weight removal include: a pressure of 101-200 kPa; and / or a reflux ratio of 0.2-5; and / or a tower top operating temperature of 82.5° C.-100.2° C.

5. The purification method according to any one of claims 1 to 4, wherein: The method further comprises: after the heavy liquid phase is deweighted, deionizing and demicroparticleizing are performed in sequence to obtain purified isopropanol.

6. The purification method according to claim 5, wherein The deionization is carried out by adsorption with ion exchange resin; preferably, the ion exchange resin is a mixed resin comprising a hydrogen-type strongly acidic cation exchange resin and a hydroxide-type strongly basic anion exchange resin, and more preferably, the mass ratio of the hydrogen-type strongly acidic cation exchange resin to the hydroxide-type strongly basic anion exchange resin is 3:1-1:3; and / or The degranulation is performed in the form of filtration; preferably, the filtration is performed using a filter element made of at least one of PFA, PTFE, and PP; more preferably, the filtration is performed in a multi-stage series manner.

7. The purification method according to any one of claims 1 to 6, wherein: The dehydration is carried out by molecular sieve adsorption and / or pervaporation.

8. The purification method according to claim 7, wherein The molecular sieve is at least one of a 3A molecular sieve, a 4A molecular sieve and a 5A molecular sieve; and / or The pervaporation uses a molecular sieve membrane, and preferably the pervaporation operation includes: an absolute pressure of 1 bar to 8 bar.

9. The purification method according to any one of claims 1 to 8, wherein: The content of isopropanol in the technical grade isopropanol is ≥ 98 wt %, preferably ≥ 99.5 wt %; and / or The industrial-grade isopropanol also contains at least one of water, methanol, ethanol, n-propanol, isopropyl ether, acetone, methyl ethyl ketone and isobutanol.

10. The purification method according to any one of claims 1 to 9, wherein: The second liquid phase is catalytically hydrogenated and then returned to the de-lightened material, which is mixed with the dehydrated material and then de-lightened together.

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