A method and system for preparing ultrapure high-purity isopropanol

Abstract

This invention relates to the field of separation and purification technology, and discloses a method and system for preparing ultra-clean, high-purity isopropanol. The method includes: isopropanol feedstock undergoing a first distillation and a first adsorption process; the first distillation removes light organic components and water, and the first adsorption removes organic impurities including water, alcohols, ethers, and ketones; the first adsorption is performed before or after the first distillation; followed by a second distillation and a second adsorption process; the second distillation removes heavy organic components and most of the metal cations and anions, and the second adsorption further removes metal cations and anions; the second adsorption is performed before or after the second distillation; followed by a third distillation to further remove water, alcohols, ethers, ketones, organic impurities, metal cations, and anions; and finally, filtration to obtain ultra-clean, high-purity isopropanol. This method can obtain ultra-clean, high-purity isopropanol products with low water content and low levels of alcohol, ketone, and ether impurities.

Description

Technical Field

[0001] This invention belongs to the field of separation and purification technology, specifically relating to a method and system for preparing ultrapure isopropanol. Background Technology

[0002] Isopropanol is a commonly used organic solvent, primarily used in pharmaceuticals, cosmetics, plastics, fragrances, and coatings. When used as a solvent for wafer cleaning and drying in the integrated circuit industry, ultra-clean, high-purity isopropanol is required. Ultra-clean, high-purity isopropanol is an important class of organic wet electronic chemicals used in high-end industries such as solar energy, displays, and semiconductors. Therefore, the requirements for organic impurities (alcohols, ketones, ethers), water content, ion content, and particulate matter content in isopropanol are extremely stringent.

[0003] Existing methods for producing ultra-clean, high-purity isopropanol typically involve dehydration followed by two distillations to remove light organic components (impurities with lower boiling points than isopropanol) and heavy organic components (impurities with higher boiling points than isopropanol). Finally, the product undergoes deionization and particulate removal to obtain the ultra-clean, high-purity isopropanol. However, this method still produces high-purity isopropanol containing certain amounts of alcohol, ether, and ketone organic impurities, as well as water, metal cations, anions, and particulate matter, significantly impacting product quality. Therefore, a new method for producing ultra-clean, high-purity isopropanol is needed to further reduce the levels of alcohol, ether, and ketone organic impurities, as well as metal cations, anions, and particulate matter in the product. Summary of the Invention

[0004] The purpose of this invention is to overcome the technical defects of existing technologies, such as poor product quality and high content of alcohol, ether, ketone organic impurities, moisture, metal cations, anions and particulate matter. This invention provides a method and system for preparing ultra-clean high-purity isopropanol. The method of this invention can obtain ultra-clean high-purity isopropanol products with low content of alcohol, ether, ketone impurities, moisture, metal cations, anions and particulate matter.

[0005] To achieve the above objectives, the present invention provides a method for preparing ultrapure, high-purity isopropanol, the method comprising:

[0006] The isopropanol feedstock undergoes a first distillation and a first adsorption. The first distillation removes light organic components and water, and the first adsorption removes organic impurities including water, alcohol, ether and ketone. The first adsorption is carried out before or after the first distillation.

[0007] Then a second distillation and a second adsorption are performed. The second distillation removes the heavy organic components and most of the metal cations and anions, and the second adsorption further removes the metal cations and anions. The second adsorption is performed before or after the second distillation.

[0008] A third distillation is then performed to further remove water, alcohols, ethers and ketones, organic impurities, metal cations and anions;

[0009] The solution was then filtered to obtain ultra-clean, high-purity isopropanol.

[0010] Another aspect of the present invention provides a method for preparing ultrapure high-purity isopropanol, the method comprising:

[0011] a) The isopropanol feedstock is subjected to a first distillation to remove light organic components and water, yielding distillate 3 in the bottom column.

[0012] b) The distillate from the bottom of the column undergoes a first adsorption process to remove organic impurities, including water, alcohols, ethers, and ketones, to obtain the adsorbed product;

[0013] c) The adsorption product is subjected to a second distillation to remove the heavy organic components and most of the metal cations and anions, to obtain the overhead distillate;

[0014] d) The distillate from the top of the column undergoes a second adsorption to further remove metal cations and anions, yielding the adsorbed product;

[0015] e) The adsorption product is subjected to a third distillation to further remove water, alcohols, ethers and ketones, organic impurities, metal cations and anions, to obtain a side distillate;

[0016] f) The side stream distillate is subjected to deep filtration to remove particulate matter, yielding ultra-clean, high-purity isopropanol.

[0017] The method for preparing ultra-clean high-purity isopropanol provided by this invention first removes light components and some water through distillation, then further removes water and light components that are difficult to remove through distillation, especially organic impurities such as alcohols, ketones, and ethers, through adsorption. Then, heavy components, a large number of metal cations and anions are removed through distillation, and the remaining metal cations and anions are removed through adsorption. Finally, water, alcohols, ketones, and ethers are removed through re-distillation. After passing through a filtration unit, the product is obtained as an ultra-clean high-purity isopropanol product with low content of alcohols, ketones, ethers, organic impurities, water, metal cations, anions, and particulate matter.

[0018] Another aspect of the present invention provides a system for preparing ultra-clean high-purity isopropanol, the system comprising: a first distillation unit and a first adsorption unit connected along the material flow direction; a second distillation unit and a second adsorption unit; a third distillation unit and a filtration unit;

[0019] The first adsorption unit is before or after the first distillation unit, and the second adsorption unit is before or after the second distillation unit.

[0020] Preferably, along the material flow direction, the system includes: a first distillation unit, a first adsorption unit, a second distillation unit, a second adsorption unit, a third distillation unit, and a filtration unit connected in series.

[0021] The system for preparing ultra-clean high-purity isopropanol of this invention uses a clever combination of multi-stage distillation units, multi-stage adsorption units, and filtration units to orderly and hierarchically remove organic impurities, especially alcohols, ethers, ketones, metal cations and anions, and particulate matter, from isopropanol, effectively reducing the impurity content in the product and improving the product quality of ultra-clean high-purity isopropanol. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the preparation method of ultra-clean high-purity isopropanol according to specific embodiments of the present invention;

[0023] Among them, ① is the first distillation unit, ② is the first adsorption unit, ③ is the second distillation unit, ④ is the second adsorption unit, ⑤ is the third distillation unit, and ⑥ is the filtration unit.

[0024] Wherein, 1 is isopropanol feedstock, 2 is the overhead distillate of the first distillation unit, 3 is the bottom distillate of the first distillation unit, 4 is the adsorption product of the first adsorption unit, 5 is the bottom distillate of the second distillation unit, 6 is the overhead distillate of the second distillation unit, 7 is the adsorption product of the second adsorption unit, 8 is the overhead distillate of the third distillation unit, 9 is the bottom distillate of the third distillation unit, 10 is the side stream distillate of the third distillation unit, and 11 is the ultra-clean high-purity isopropanol product. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] This invention provides a method for preparing ultrapure, high-purity isopropanol, the method comprising:

[0027] The isopropanol feedstock undergoes a first distillation and a first adsorption. The first distillation removes light organic components and water, and the first adsorption removes organic impurities including water, alcohol, ether and ketone. The first adsorption is carried out before or after the first distillation.

[0028] Then a second distillation and a second adsorption are performed. The second distillation removes the heavy organic components and most of the metal cations and anions, and the second adsorption further removes the metal cations and anions. The second adsorption is performed before or after the second distillation.

[0029] A third distillation is then performed to further remove water, alcohols, ethers and ketones, organic impurities, metal cations and anions;

[0030] The solution was then filtered to obtain ultra-clean, high-purity isopropanol.

[0031] In this invention, the second adsorption occurs before the second distillation unit, and the second and third distillations can be combined using a single distillation column.

[0032] According to a preferred embodiment of the present invention, the present invention provides a method for preparing ultrapure high-purity isopropanol, the method comprising:

[0033] a) Isopropanol 1 feedstock is subjected to a first distillation to remove light organic components, yielding overhead effluent 2 and bottom distillate 3;

[0034] b) The distillate 3 from the bottom of the column undergoes a first adsorption process to remove organic impurities, including water, alcohols, ethers, and ketones, to obtain the adsorbed product 4;

[0035] c) The adsorbed product 4 is subjected to a second distillation to remove the heavy organic components and most of the metal cations and anions, to obtain the bottom effluent 5 and the top distillate 6.

[0036] d) The distillate 6 from the top of the column undergoes a second adsorption to further remove metal cations and anions, yielding the adsorbed product 7;

[0037] e) The adsorption product 7 is subjected to a third distillation to further remove water, alcohol, ether, ketone organic impurities, metal cations and anions, to obtain the overhead effluent 8, the bottom effluent 9 and the side stream distillate 10.

[0038] f) The side stream distillate is subjected to deep filtration to remove particulate matter, yielding an ultra-clean, high-purity isopropanol product 11.

[0039] This invention does not have special requirements for the feed location of the first distillation. According to a preferred embodiment of this invention, the feed for the first distillation is located in the upper middle part of the distillation column. The purpose of the first distillation is to remove light components and moisture from the isopropanol feedstock. To ensure the removal effect of light components, the feed location is preferably set in the upper middle part of the distillation column.

[0040] In this invention, the purpose of the first distillation is to remove light organic components and moisture. The operating conditions are determined according to the material. According to a preferred embodiment of this invention, the operating pressure (absolute pressure) of the first distillation is 101.325 kPa-150 kPa; the reflux ratio is 2-30; and the reboiler temperature is controlled at 82.5℃-93.0℃.

[0041] According to a preferred embodiment of the present invention, the operating pressure (absolute pressure) of the first distillation is preferably 101.325 kPa-125 kPa; the reflux ratio is preferably 8-20.

[0042] According to a preferred embodiment of the present invention, the operating pressure (absolute pressure) of the first distillation is 101.325 kPa-150 kPa, a slightly positive pressure distillation method. This prevents organic impurities from outside the system from entering the system during distillation and increases the boiling point difference between the light components and isopropanol, which helps in the removal of the light components. The preferred operating pressure (absolute pressure) is 101.325 kPa-125 kPa, which achieves the above objectives without introducing excessive pressure and increasing the energy consumption of the overhead condenser and reboiler. Similarly, to ensure the recovery rate of isopropanol during the removal of light components, this process needs to be operated at a relatively large reflux ratio. However, a large reflux ratio can affect the removal efficiency of the light components. Studies have found that a reflux ratio range of 2-30 has good effects, with a preferred reflux ratio of 8-20.

[0043] Considering that isopropanol and water form a minimum azeotropic system, some water will also distill off from the top of the distillation column during the first distillation process. Therefore, in the process of removing light components from isopropanol, the first distillation also removes some water, significantly reducing the water content in the bottom product.

[0044] The present invention does not have special requirements for the operating conditions of the first adsorption, as long as the removal of organic impurities including water, alcohol, ether, and ketone is ensured. According to a preferred embodiment of the present invention, the first adsorption is carried out in an adsorption column, with the feed from the bottom of the adsorption column.

[0045] This invention does not have special requirements for the operating conditions of the first adsorption step, as long as the removal of organic impurities including water, alcohols, ethers, and ketones is ensured. The selection of the adsorbent is not particularly demanding. According to a preferred embodiment of this invention, the adsorption column is filled with a mixed molecular sieve containing type 4A and type 5A molecular sieves; preferably, the packing ratio of type 4A to type 5A molecular sieves is 1:3 to 3:1. Due to their close boiling points and the presence of multiple azeotropes, the first distillation process is unlikely to completely remove alcohols, ethers, and ketones from isopropanol. Therefore, the product after distillation still contains a certain amount of alcohols, ethers, and ketones. The purpose of the first adsorption step is to remove these organic impurities and continue to remove water. The adsorption column is a common adsorption device. Since it uses liquid-phase feeding, feeding from the bottom of the adsorption column is more convenient for operation. Studies have found that type 4A molecular sieves have a good adsorption capacity for water in the isopropanol system, while type 5A molecular sieves, in addition to having a certain adsorption capacity for water, also have a very good adsorption capacity for alcohols, ethers, and ketones in isopropanol. Therefore, in a preferred embodiment, a mixed molecular sieve of type 4A and type 5A is packed into the adsorption column to jointly remove water and organic impurities such as alcohols, ethers, and ketones from the bottom product after the first distillation. In order to ensure the removal effect of water and organic impurities such as alcohols, ethers, and ketones from the bottom product after the first distillation, it is necessary to set the packing ratio of type 4A molecular sieve to type 5A molecular sieve in the adsorption column. Studies have found that a packing ratio of type 4A molecular sieve to type 5A molecular sieve of 1:3 to 3:1 has a better removal effect of water and organic impurities such as alcohols, ethers, and ketones.

[0046] According to a preferred embodiment of the present invention, in order to ensure the effectiveness of the mixed molecular sieve, it needs to be activated at 250℃-500℃ for 3h-5h before use to further remove organic impurities and moisture from the molecular sieve pores.

[0047] According to a preferred embodiment of the present invention, the second distillation feed is located in the lower middle section of the distillation column. The purpose of the second distillation is to remove heavy components and most of the metal cations and anions from the product after the first adsorption. To ensure the removal efficiency of heavy components and metal cations and anions, the feed location is preferably set in the lower middle section of the distillation column. After the first adsorption, a large number of cations and anions are enriched in the product. During the second distillation process, most of these ions are enriched in the bottom of the column, and the content of metal cations and anions in the top distillate will be greatly reduced.

[0048] According to a preferred embodiment of the present invention, the operating pressure (absolute pressure) of the second distillation is 101.325 kPa-150 kPa; the reflux ratio is 0.2-10; and the top temperature of the column is controlled at 82.0℃-92.5℃. The operating pressure (absolute pressure) is preferably 101.325 kPa-125 kPa; the reflux ratio is preferably 0.5-2. The second distillation uses a slightly positive pressure distillation method with an operating pressure (absolute pressure) of 101.325 kPa-150 kPa. This method can prevent organic impurities from outside the system from entering the system during distillation and can also increase the boiling point difference between isopropanol and heavy components, which helps in the removal of heavy components. The operating pressure (absolute pressure) is preferably 101.325 kPa-125 kPa. Within this range, the above objectives can be achieved without introducing excessively high pressure, which would increase the energy consumption of the top condenser and the reboiler. Similarly, to ensure the recovery rate of isopropanol during the removal of moisture, heavy components, metal cations, and anions, this process needs to be operated at a relatively small reflux ratio. However, a small reflux ratio can affect the removal efficiency of heavy components, metal cations, and anions. Studies have found that a reflux ratio in the range of 0.2-10 yields good results, with the preferred reflux ratio being 0.5-2.

[0049] This invention does not have special requirements for the operating conditions of the second adsorption, as long as the residual metal cations and anions are removed. The choice of adsorbent is also not special. According to a preferred embodiment of this invention, the second adsorption is carried out using an adsorption device with at least two adsorption columns connected in series, and along the material flow direction, boron removal resin and mixed-bed resin are respectively filled. The purpose of the second adsorption is to remove impurity elements such as boron and residual other metal cations and anions from the overhead distillate after the second distillation. According to the removal sequence, impurity elements such as boron can be removed first, followed by the removal of other metal cations and anions, to prevent the generation of new anions and cations during boron removal, which would ultimately be carried into the product.

[0050] According to a preferred embodiment of the present invention, the boron-removing resin is a chelating resin, and the mixed-bed resin comprises a strong acidic cation exchange resin and a strong basic anion exchange resin. Studies have found that the combined application of the above resins has good effects on the removal of boron and other metal cations and anions, and can ensure that the boron and other metal cations and anions in the removed product meet the corresponding requirements.

[0051] According to a preferred embodiment of the present invention, the boron-removing resin and mixed-bed resin are subjected to a product replacement treatment before use, with the product dosage being 2-20 times the volume of the filled resin. The boron-removing resin and mixed-bed resin contain a large amount of water and a small amount of organic and inorganic impurities. Treating the resin with the product before use can remove the water and organic and inorganic impurities, thus avoiding any impact on product quality. Studies have found that using a product dosage of 2-20 times the volume of the filled resin effectively removes water and organic and inorganic impurities from the resin.

[0052] According to a preferred embodiment of the present invention, the third distillation feed is located in the lower middle part of the distillation column; the purpose of the third distillation is to remove the residual metal cations and anions and organic impurities such as alcohols, ethers, and ketones from the product after the second adsorption. The organic impurities such as alcohols, ethers, and ketones can be distilled from the top of the third distillation column, while water, metal cations, and anions are mainly distilled from the bottom of the third distillation column. In order to ensure the removal effect of metal cations and anions, as well as organic impurities such as alcohols, ketones, and ethers, the feed position needs to be set in the lower middle part of the distillation column.

[0053] In this invention, the purpose of the third distillation is to further remove water, alcohols, ethers, ketones, organic impurities, metal cations, and anions. The operating conditions are determined based on the materials. According to a preferred embodiment of this invention, the operating pressure (absolute pressure) of the third distillation is 101.325 kPa-150 kPa; the reflux ratio is 0.2-10; and the top temperature of the column is controlled at 82.0℃-92.5℃. The preferred operating pressure (absolute pressure) is 101.325 kPa-125 kPa; and the preferred reflux ratio is 0.5-2. The third distillation adopts a slightly positive pressure distillation method with an operating pressure (absolute pressure) of 101.325 kPa-150 kPa, which can prevent organic impurities from outside the system from entering the system during the distillation process, and can also increase the boiling point difference between isopropanol and alcohols, ethers, and ketones, which helps to remove light components. Within the above pressure range, it also has a good removal capacity for metal cations and anions. The optimal operating pressure (absolute pressure) is 101.325 kPa–125 kPa. Within this range, the above objectives are achieved without introducing excessive pressure, which would increase the energy consumption of the overhead condenser and the reboiler. To ensure the removal of alcohols, ethers, and ketones from the top of the column, and the removal of residual metal cations and anions from the bottom, the reflux ratio needs to be strictly controlled. A reflux ratio that is too high can lead to incomplete removal of alcohols, ethers, and ketones, while a reflux ratio that is too low can result in reduced isopropanol recovery and poor removal of metal cations and anions. Studies have found that a reflux ratio in the range of 0.2–10 yields good results, with 0.5–2 being the preferred range.

[0054] According to a preferred embodiment of the present invention, the overhead distillate of the third distillation column is returned to the feed position of the first and / or second distillation column; the bottom distillate of the third distillation column is returned to the feed position of the second and / or first distillation column; a side stream distillate is collected from the upper middle section of the third distillation column; the overhead product of the third distillation column contains organic impurities such as alcohols, ethers, and ketones, which are light components, and this stream is returned to the first distillation unit and fed together with the isopropanol feedstock; the bottom product of the third distillation column contains a small amount of metal cations and anions, which can be returned to the second and / or first distillation unit for removal. A side stream is provided in the upper middle section of the third distillation column, where ultra-clean, high-purity isopropanol product can be obtained.

[0055] According to a preferred embodiment of the present invention, the filtration is carried out in a filtration device, which is a multi-stage filtration device, preferably 4-10 stages. Preferably, the particle size cutoff of the four-stage filters is 0.5μm, 0.2μm, 0.1μm and 50nm, or 0.5μm, 0.1μm, 50nm and 30nm, respectively. The filtration device is a common filtration device, containing components such as pipes, valves, filter housings and filters. The filter element is, for example, a filter membrane made of materials such as PFA, PTFE, and PE, and is installed inside the filter housing. Research has found that in the multi-stage filtration device, at least one stage of the filter element uses an ion exchange membrane, which can further reduce the ion content in the product. For example, a five-stage filtration device is used, where the first stage filter element uses an ion exchange membrane (model: MGSX110OTCPUHD), and the particle size cutoff of the remaining four stages is set to 0.5μm, 0.1μm, 50nm and 30nm.

[0056] According to a preferred embodiment of the present invention, the isopropanol raw material has an isopropanol purity ≥ 98.0%, and / or a water content ≤ 2000 ppm, and / or an alcohol impurity content ≤ 1000 ppm, and / or an ether impurity content ≤ 1000 ppm, and / or a ketone impurity content ≤ 1000 ppm. Alcohol impurities include methanol, ethanol, n-propanol, n-butanol, n-pentanol, isobutanol, tert-butanol, 2-hexanol, etc.; ether impurities include diethyl ether, isopropyl ether, etc.; and ketone impurities include acetone, butanone, pentanone, etc. Raw materials within the above ranges can be used to prepare ultra-clean, high-purity isopropanol through this process. However, it is not limited to isopropanol raw materials exceeding this range that cannot be used to prepare ultra-clean, high-purity isopropanol using this invention.

[0057] According to a preferred embodiment of the present invention, the isopropanol raw material has an isopropanol purity ≥ 98.0%, a water content ≤ 2000 ppm, an alcohol impurity content ≤ 1000 ppm, an ether impurity content ≤ 1000 ppm, and a ketone impurity content ≤ 1000 ppm.

[0058] In this invention, isopropanol raw materials generally contain metal ions and anions, which are known to those skilled in the art and will not be described in detail here.

[0059] According to a preferred embodiment of the method of the present invention, the ultra-clean high-purity isopropanol has a purity ≥99.999%, and / or a water content ≤30ppm, and / or an alcohol impurity content ≤10ppm, and / or an ether impurity content ≤10ppm, and / or a ketone impurity content ≤10ppm, and / or a single metal cation content ≤10ppt, and / or a single anion content ≤5ppb, and / or a particle size (≥50nm) ≤100 particles / ml.

[0060] Another aspect of the present invention provides a system for preparing ultrapure high-purity isopropanol, the system comprising:

[0061] Along the material flow direction, the following units are connected: the first distillation unit ①, the first adsorption unit ②; the second distillation unit ③, the second adsorption unit ④; the third distillation unit ⑤, and the filtration unit ⑥.

[0062] The first adsorption unit is located before or after the first distillation unit, and the second adsorption unit is located before or after the second distillation unit.

[0063] According to a preferred embodiment of the present invention, the system includes: a first distillation unit ①, a first adsorption unit ②, a second distillation unit ③, a second adsorption unit ④, a third distillation unit ⑤, and a filtration unit ⑥, which are connected in series along the material flow direction.

[0064] According to a preferred embodiment of the present invention, in the system for preparing ultrapure high-purity isopropanol, the first distillation unit includes a distillation column.

[0065] According to a preferred embodiment of the present invention, in the system for preparing ultrapure isopropanol, the first adsorption unit is an adsorption device containing an adsorption column, the adsorption column being filled with a mixed molecular sieve containing type 4A molecular sieve and type 5A molecular sieve; preferably, the filling ratio of type 4A molecular sieve to type 5A molecular sieve is 1:3-3:1.

[0066] According to a preferred embodiment of the present invention, in the system for preparing ultrapure high-purity isopropanol, the second distillation unit includes a distillation column.

[0067] According to a preferred embodiment of the present invention, in the system for preparing ultrapure isopropanol, the second adsorption unit includes an adsorption device with at least two adsorption columns connected in series, and is respectively filled with deboronizing resin and mixed bed resin along the material flow direction. The deboronizing resin is a chelating resin, and the mixed bed resin contains a strong acid cation exchange resin and a strong base anion exchange resin.

[0068] According to a preferred embodiment of the present invention, in the system for preparing ultrapure high-purity isopropanol, the third distillation unit includes a distillation column, preferably provided with a middle and upper side stream outlet.

[0069] According to a preferred embodiment of the present invention, in the system for preparing ultrapure high-purity isopropanol, the filtration unit includes a multi-stage filtration device connected in series.

[0070] According to a preferred embodiment of the present invention, the reboiler outlet of the third distillation unit is connected to the feed inlet of the second distillation and / or the first distillation unit.

[0071] According to a preferred embodiment of the present invention, the top outlet of the third distillation unit is connected to the feed inlet of the first distillation and / or the second distillation unit.

[0072] The system for preparing high-purity isopropanol of this invention uses a clever combination of distillation, adsorption and filtration units to orderly and hierarchically remove organic impurities, especially alcohols, ethers, ketones, water, metal cations and anions, and particulate matter from isopropanol, effectively reducing the impurity content in the product and improving the quality of ultra-clean high-purity isopropanol.

[0073] The present invention will be further described below through specific embodiments. The scope of the present invention is not limited to the scope covered by the embodiments. In the embodiments, the purity of the product, ketones, ethers, and ketone organic impurities were detected by gas chromatography (Agilent GC7890), the moisture content was determined by Karl Fischer moisture analyzer (Mettler V30S), the metal ions were determined by ICP-MS / MS (Agilent 8900), the anions were determined by ion chromatography (Thermo Fisher ICS-6000+), and the particle number was determined by liquid particle counter (RIONKS-19F).

[0074] Example 1

[0075] A batch of isopropanol feedstock was tested and found to have an isopropanol purity of 99.9%, a water content of 480 ppm, alcohol impurities (mainly ethanol) of 270 ppm, ether impurities (mainly isopropyl ether) of 180 ppm, ketone impurities (mainly acetone) of 340 ppm, and other organic impurities of 210 ppm. This feedstock was introduced from the upper part of the first distillation unit, which operated at a pressure of 120 kPa, a reflux ratio of 10, and a reboiler temperature of 87°C. The resulting reboiler distillate entered from the bottom of the first adsorption unit, which was packed with a mixture of 4A and 5A molecular sieves at a volume ratio of 1:1 (the mixed molecular sieves were activated at 350°C for 4 hours before use). The product after adsorption treatment in the first adsorption unit entered the second distillation unit from the lower part, which operated at a pressure of 120 kPa, a reflux ratio of 1, and a top temperature of 86.5°C. The distillate from the second distillation unit enters from the top of the second adsorption unit and is sequentially processed through adsorption columns packed with Ambertec UP7530 deboronizing resin and AMBERJET UP6040 mixed-bed resin (composed of a strong acidic cation exchange resin and a strong basic anion exchange resin). (Before use, the resin is replaced with 10 times its volume of product; the amount of product used is 10 times the volume of the packed resin.) The adsorbed product from the second adsorption treatment enters the third distillation unit from the lower part. The operating pressure of the third distillation unit is 120 kPa, the reflux ratio is 1, and the operating temperature at the top of the column is controlled at 86.5℃. The product obtained from the side stream enters the filtration unit. The filtration unit uses a four-stage filter connected in series, with the filter particle size cutoffs set at 0.5 μm, 0.2 μm, 0.1 μm, and 50 nm, ultimately yielding ultra-clean, high-purity isopropanol.

[0076] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9996%, the content of alcohol and ether organic impurities was undetectable, the acetone content was 4 ppm, the water content was 30 ppm, the single metal cation content was ≤8 ppt, the single anion content was ≤3 ppb, and the particle size (≥50 nm) was 23 particles / ml. The content of the main cations (ppt) in the product is shown in Table 1, and the content of the main anions (ppb) in the product is shown in Table 2.

[0077] Table 1. Content of major cations in the product (ppt)

[0078]

[0079]

[0080] Table 2. Content of major anions in the product (ppb)

[0081] anions unit After separation <![CDATA[F - ]]> ppb 1 <![CDATA[Cl - ]]> ppb 2 <![CDATA[Br - ]]> ppb 1 <![CDATA[NO2 - ]]> ppb 3 <![CDATA[NO3 - ]]> ppb 2 <![CDATA[PO4 3- ]]> ppb 1 <![CDATA[SO4 2- ]]> ppb 1

[0082] Example 2

[0083] Following the method of Example 1, the same isopropanol raw material was used, except that the filtration unit adopted a 4-stage filter connected in series. The filter's particle size specifications were set to 0.5μm, 0.1μm, 50nm, and 30nm, and finally, ultra-clean high-purity isopropanol was obtained.

[0084] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9997%, the content of alcohol and ether organic impurities was undetectable, the acetone content was 3 ppm, the water content was 27 ppm, the single metal cation was ≤9 ppt, the single anion was ≤4 ppb, the particle size (≥50 nm) was 5 particles / ml, and the particle size (>30 nm) was 20 particles / ml.

[0085] Example 3

[0086] Following the method of Example 1, the same isopropanol raw material was used, except that the filtration unit adopted a 5-stage filter connected in series. The filter element of the first stage filter was an ion exchange membrane (model: MGSX110OTCPUHD), and the particle size specifications of the remaining 4 stages of filters were set to 0.5μm, 0.1μm, 50nm and 30nm, respectively, and finally ultra-clean high-purity isopropanol was obtained.

[0087] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9998%, the content of alcohol and ether organic impurities was undetectable, the acetone content was 2 ppm, the water content was 25 ppm, the single metal cation was ≤5 ppt, the single anion was ≤3 ppb, the particle size (≥50 nm) was 3 particles / ml, and the particle size (≥30 nm) was 18 particles / ml.

[0088] Comparative Example 1

[0089] Following the method of Example 1, using the same isopropanol raw material, the difference being the absence of a first adsorption unit, ultra-clean high-purity isopropanol was finally obtained.

[0090] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9965%, ethanol was 20 ppm, isopropyl ether was 5 ppm, acetone was 10 ppm, water was 80 ppm, single metal cation was ≤9 ppt, single anion was ≤4 ppb, and particle size (≥50 nm) was 41 particles / ml.

[0091] Comparative Example 2

[0092] Following the method of Example 1, using the same isopropanol raw material, the difference is the absence of a third distillation unit, ultimately yielding ultra-clean, high-purity isopropanol.

[0093] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.992%, the content of alcohol organic impurities was undetectable, the content of isopropyl ether was 50 ppm, the content of acetone was 30 ppm, the content of water was 160 ppm, the single metal cation was ≤10 ppt, the single anion was ≤5 ppb, and the particle size (≥50 nm) was 52 particles / ml.

[0094] Comparative Example 3

[0095] Following the method of Example 1, using the same isopropanol raw material, the difference is that the second adsorption unit is placed after the third distillation unit, and finally ultra-clean high-purity isopropanol is obtained.

[0096] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.995%, the content of alcohol organic impurities was undetectable, the content of isopropyl ether was 30 ppm, the content of acetone was 20 ppm, the content of water was 130 ppm, the single metal cation was ≤8 ppt, the single anion was ≤5 ppb, and the particle size (≥50 nm) was 38 particles / ml.

[0097] Example 4

[0098] Following the method of Example 1, the same isopropanol raw material was used, except that the first adsorption unit was placed before the first distillation unit, and ultra-clean high-purity isopropanol was finally obtained.

[0099] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9995%, the content of alcohol and ether organic impurities was undetectable, the acetone content was 5 ppm, the water content was 33 ppm, the single metal cation was ≤10 ppt, the single anion was ≤4 ppb, and the particle size (≥50 nm) was 25 particles / ml.

[0100] Example 5

[0101] Following the method of Example 1, using the same isopropanol raw material, the difference is that the second adsorption unit is placed before the second distillation unit, and finally ultra-clean high-purity isopropanol is obtained.

[0102] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9993%, the content of alcohol and ether organic impurities was undetectable, the acetone content was 7 ppm, the water content was 42 ppm, the single metal cation was ≤9 ppt, the single anion was ≤5 ppb, and the particle size (≥50 nm) was 25 particles / ml.

[0103] Example 6

[0104] The method of Example 1 is followed, except that the purity of the isopropanol raw material is 99.85%, the water content is 1100 ppm, the alcohol impurities are 530 ppm, the ether impurities are 220 ppm, the ketone impurities are 430 ppm, and the other organic impurities are 320 ppm, and finally ultra-clean high-purity isopropanol is obtained.

[0105] The product was analyzed according to the analytical method specified in standard SEMI C41-0618. The purity of the obtained ultra-clean high-purity isopropanol was 99.9994%, the content of alcohol and ether organic impurities was undetectable, the acetone content was 6 ppm, the water content was 34 ppm, the single metal cation was ≤9 ppt, the single anion was ≤3 ppb, and the particle size (≥50 nm) was 32 particles / ml.

Claims

1. A method for preparing ultra-clean, high-purity isopropanol, characterized in that, The method includes: a) The isopropanol feedstock undergoes a first distillation to remove light organic components and moisture, yielding a bottom distillate; b) The distillate from the bottom of the column undergoes a first adsorption process to remove organic impurities, including water, alcohols, ethers, and ketones, to obtain the adsorbed product; c) The adsorption product is subjected to a second distillation to remove the heavy organic components and most of the metal cations and anions, to obtain the overhead distillate; d) The distillate from the top of the column undergoes a second adsorption to further remove metal cations and anions, yielding the adsorbed product; e) The adsorption product is subjected to a third distillation to further remove water, alcohols, ethers and ketones, organic impurities, metal cations and anions, to obtain a side distillate; f) The side stream distillate is subjected to deep filtration to remove particulate matter, metal cations and anions, to obtain ultra-clean high-purity isopropanol.

2. The method according to claim 1, wherein, The first distillation feed is located in the upper middle part of the distillation column: the operating pressure of the distillation column is 101.325 kPa - 150 kPa; the reflux ratio is 2-30; and the reboiler temperature is controlled at 82.5℃-93.0℃.

3. The method according to claim 2, wherein, Operating pressure is 101.325 kPa - 125 kPa; reflux ratio is 8-20.

4. The method according to claim 1, wherein, The first adsorption occurs inside an adsorption column, with feed introduced from the bottom of the column. The adsorption column is filled with a mixed molecular sieve containing type 4A and type 5A molecular sieves.

5. The method according to claim 4, wherein, The filling ratio of the 4A type molecular sieve to the 5A type molecular sieve is 1:3 to 3:1; the mixed molecular sieve needs to be activated at 250℃-500℃ for 3h-5h before use.

6. The method according to claim 1, wherein, The second distillation feed is located in the lower middle part of the distillation column: the operating pressure of the distillation column is 101.325 kPa-150 kPa; the reflux ratio is 0.2-10; and the top temperature of the column is controlled at 82.0℃-92.5℃.

7. The method according to claim 6, wherein, The operating pressure is 101.325 kPa-125 kPa; the reflux ratio is 0.5-2.

8. The method according to claim 1, wherein, The second adsorption is carried out using an adsorption device with at least two adsorption columns connected in series, and along the material flow direction, deboronizing resin and mixed bed resin are respectively filled. The deboronizing resin is a chelating resin, and the mixed bed resin contains a strong acidic cation resin and a strong basic anion resin.

9. The method according to claim 8, wherein, The deboronized resin and mixed bed resin are subjected to product replacement treatment before use.

10. The method according to claim 1, wherein, The third distillation feed is located in the lower middle part of the distillation column: the operating pressure of the distillation column is 101.325 kPa-150 kPa; the reflux ratio is 0.2-10; and the top temperature of the column is controlled at 82.0℃-92.5℃.

11. The method according to claim 10, wherein, The operating pressure is 101.325 kPa-125 kPa; the reflux ratio is 0.5-2.

12. The method according to claim 1, wherein, The overhead distillate from the third distillation column is returned to the feed location of the first and / or second distillation columns; and / or The bottom distillate of the third distillation column is returned to the feed location of the second and / or first distillation column; and / or The side stream distillate is collected from the upper middle part of the third distillation column.

13. The method according to claim 1, wherein, The filtration is carried out in a filtration device, which is a multi-stage system connected in series.

14. The method according to claim 13, wherein, The filtration device consists of 4-10 stages connected in series.

15. The method according to claim 13, wherein, In the multi-stage filtration device connected in series, at least one stage of the filter element uses an ion exchange membrane.

16. The method according to claim 1, wherein, The isopropanol raw material has an isopropanol purity of ≥98.0%, a water content of ≤2000ppm, an alcohol impurity content of ≤1000ppm, an ether impurity content of ≤1000ppm, and a ketone impurity content of ≤1000ppm.

17. The method according to claim 1, wherein, Ultra-clean high-purity isopropanol purity ≥99.999%, and / or water content ≤30ppm, and / or alcohol impurity content ≤10ppm, and / or ether impurity content ≤10ppm, and / or ketone impurity content ≤10ppm, and / or single metal cation content ≤10ppt, and / or single anion content ≤5ppb, and / or particle size (particle size ≥50nm) ≤100 particles / ml.

18. A system used in the method for preparing ultrapure high-purity isopropanol according to any one of claims 1-17, characterized in that, The system includes: Along the material flow direction, the following units are connected: the first distillation unit, the first adsorption unit; the second distillation unit, the second adsorption unit; the third distillation unit, and the filtration unit. The first adsorption unit is located after the first distillation unit, and the second adsorption unit is located after the second distillation unit.

19. The system according to claim 18, wherein, Along the material flow direction, the system includes: a first distillation unit, a first adsorption unit, a second distillation unit, a second adsorption unit, a third distillation unit, and a filtration unit connected in series.

20. The system according to claim 18, wherein, The first distillation unit includes a distillation column; and / or The first adsorption unit is an adsorption device containing an adsorption column, which is filled with a mixed molecular sieve containing type 4A and type 5A molecular sieves; and / or The second distillation unit includes a distillation column; and / or The second adsorption unit includes an adsorption device with at least two adsorption columns connected in series, and is respectively filled with boron-removing resin and mixed-bed resin along the material flow direction. The boron-removing resin is a chelating resin, and the mixed-bed resin is a resin containing a strongly acidic cation exchange resin and a strongly basic anion exchange resin; and / or The third distillation unit includes a distillation column; and / or The filtration unit includes at least a number of filtration devices connected in series.

21. The system according to claim 20, wherein, The filling ratio of the 4A molecular sieve to the 5A molecular sieve is 1:3-3:1; and / or The distillation column of the third distillation unit is equipped with a side feed outlet at the top.

22. The system according to claim 20, wherein, The reboiler outlet of the third distillation unit is connected to the feed inlet of the second distillation unit and / or the first distillation unit; and / or The top outlet of the third distillation unit is connected to the feed inlet of the first distillation unit and / or the second distillation unit.

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