Method for removing water-insoluble carbonyl impurities in isopropanol
By introducing modified β-molecular sieves into the distillation column and optimizing the distillation process, the problem of removing water-insoluble carbonyl impurities from isopropanol was solved, enabling the production of high-purity isopropanol, which is suitable for use as a cleaning agent and solvent for high-end electronic components.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU JIMCEL ELECTRONICS NEW MATERIAL
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-01
AI Technical Summary
Existing technologies are insufficient to effectively remove water-insoluble carbonyl impurities from isopropanol, resulting in its purity failing to meet the stringent standards for electronic-grade isopropanol, thus affecting the performance and stability of high-end electronic components.
Modified β-molecular sieves were introduced into the packing of the distillation column, and water-insoluble carbonyl impurities in isopropanol were simultaneously removed by optimizing distillation process parameters, including pressure, temperature and reflux ratio.
Without adding processing steps, the carbonyl compound content in isopropanol is significantly reduced to below 50 ppm, meeting the purity requirements of electronic-grade isopropanol, and is suitable for semiconductor, microelectronics and precision machinery and other fields.
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Figure CN121949073A_ABST
Abstract
Description
A method for removing water-insoluble carbonyl impurities from isopropanol Technical Field
[0001] This invention belongs to the field of isopropanol purification technology, specifically relating to a method for removing water-insoluble carbonyl impurities from isopropanol. Background Technology
[0002] Isopropanol is an important organic solvent widely used in industrial production. High-purity electronic-grade isopropanol is an indispensable key material in high-end fields such as semiconductors, microelectronics, optoelectronics and precision machinery. It is often used as a cleaning agent and solvent to clean circuit boards and remove organic residues such as fingerprints and grease.
[0003] Compared to ordinary industrial-grade isopropanol, electronic-grade isopropanol has extremely strict requirements regarding purity, moisture, particle size, and various impurities. This is because if isopropanol products do not meet the relevant standards, they can easily contaminate precision electronic components during use, thereby adversely affecting the performance and stability of electronic components, and even leading to product scrapping.
[0004] However, industrially produced isopropanol often contains small amounts of carbonyl compound impurities, some of which are insoluble in water. This causes the isopropanol to form a suspension in water solubility tests, directly affecting its performance. Currently, industrially, the content of carbonyl compound impurities in isopropanol is typically controlled to below 200 ppm, far from meeting the stringent standards for electronic-grade isopropanol. Therefore, further purification of industrial-grade isopropanol is urgently needed.
[0005] Existing methods for purifying isopropanol mainly include distillation, adsorption, and ion exchange resin purification. Among these, distillation (rectification) is the most widely used in industrial production due to its relatively mature technology and large processing capacity. However, this method has significant drawbacks: firstly, it has high energy consumption, leading to high production costs; secondly, it is difficult to effectively separate azeotropes in mixed systems. The core reason is that when azeotropes composed of different components boil, their vapor composition is completely identical to that of the original mixed liquid. Conventional distillation methods cannot utilize the differences in volatility between components to achieve separation. This also makes it difficult for existing distillation processes to reduce the content of carbonyl compound impurities in isopropanol to the range required by electronic grade standards, thus failing to meet the application requirements of high-end fields. Summary of the Invention
[0006] The purpose of this invention is to address at least one of the technical problems mentioned above in the background section by proposing a method for removing water-insoluble carbonyl impurities from isopropanol.
[0007] To achieve the above objectives, the present invention employs the following technical means: a method for removing water-insoluble carbonyl impurities from isopropanol, wherein when industrial-grade isopropanol is subjected to distillation separation, modified β molecular sieves are added to the packing material in the distillation column; the modified β molecular sieves account for 10-20% of the total packing material mass.
[0008] By introducing modified β-molecular sieves into the packing material of the distillation column during the conventional industrial-grade isopropanol distillation separation process, the water-insoluble carbon-based impurities in isopropanol can be removed simultaneously during distillation without adding any processing steps. This method is simple, convenient, and easy to operate.
[0009] More preferably, the pressure is controlled at atmospheric pressure during the above-mentioned distillation separation process, the bottom temperature of the distillation column is controlled at 80-100℃, the top temperature at 86℃, and the reflux ratio at 8-10.
[0010] More preferably, the modified β molecular sieve is arranged in the distillation column by dividing the modified β molecular sieve into three parts and filling them into the upper, middle and lower parts of the packing in the distillation column, respectively.
[0011] By uniformly dividing the modified β molecular sieve into three parts and filling them into the upper, middle and lower parts of the packing in the distillation column, it is easier for the modified β molecular sieve to contact the gaseous substances in the distillation column, and it is more convenient and faster to remove water-insoluble carbonyl impurities from isopropanol.
[0012] More preferably, the modified β-molecular sieve is a β-molecular sieve modified by metal ion impregnation; the metal content of the modified β-molecular sieve is 0.5-5%.
[0013] More preferably, the modified β molecular sieve is prepared by the following method: β molecular sieve with a silicon-to-aluminum ratio of 20-100 is immersed in a metal salt impregnation solution at 10-40℃ for 2-8 hours, then filtered, dried, and then placed in a furnace at a calcination temperature of 400-600℃ for 2-6 hours to obtain the modified β molecular sieve.
[0014] More preferably, the metal salt impregnation solution is one or a mixture of several solutions selected from the following: a cobalt nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L, a cerium nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L, a copper nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L, and a nickel nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L.
[0015] Further preferably, the aforementioned industrial-grade isopropanol requires a drying pretreatment before distillation to ensure that the water content is below 1000 ppm and the carbonyl compound content is below 200 ppm. This drying pretreatment, controlling the water content below 1000 ppm, prevents excessive water content from affecting the adsorption of water-insoluble carbonyl impurities by the modified β-molecular sieve during distillation.
[0016] More preferably, the above-mentioned drying pretreatment involves adding 4A molecular sieves to isopropanol, stirring at 25°C for 3-6 hours, and filtering to obtain isopropanol with a water content of less than 1000 ppm and a carbonyl compound content of less than 200 ppm.
[0017] In a further preferred embodiment, the above-mentioned industrial-grade isopropanol is further subjected to a process of replacing or regenerating the modified β molecular sieve during the distillation separation process. That is, when the water solubility test result of the treated isopropanol in the distillation column shows slight turbidity, the distillation is stopped, and then the modified β molecular sieve is removed from the distillation column for replacement or regeneration.
[0018] More preferably, the above regeneration process involves soaking the used modified β molecular sieve in ethanol for 2-8 hours, then transferring it to a constant temperature water bath at 60-100℃ to evaporate it to dryness, then purging it with nitrogen in a drying oven at 100-150℃ for 2-8 hours, and finally calcining it in a muffle furnace at a temperature of 400-600℃ for 2-6 hours to obtain the regenerated modified β molecular sieve.
[0019] Compared with existing technologies, the advantages of this invention are as follows: By introducing modified β-molecular sieves into the packing material of the distillation column during the conventional industrial-grade isopropanol distillation separation process, and by appropriately adjusting the distillation process parameters, this invention achieves the simultaneous removal of water-insoluble carbon-based impurities from isopropanol during distillation without adding any processing steps. This method is simple and convenient, and can be widely applied to the improvement of existing isopropanol production without requiring extensive modifications to production equipment, resulting in low production investment.
[0020] This invention utilizes the excellent adsorption capacity of modified β-zeolites prepared through a special modification method. By combining the modified β-zeolite with a distillation process, water-insoluble carbon-based impurities in isopropanol can be removed during distillation, reducing the carbonyl compound impurity content to below 50 ppm, which is superior to the industrial-grade standard of 200 ppm. This makes isopropanol, after only a distillation separation process, suitable for applications in semiconductors, microelectronics, optoelectronics, and precision machinery. Attached Figure Description
[0021] Figure 1 is a comparison of the water solubility test results in Example 1 and Comparative Example 1 of the present invention (where the beaker on the right is the result in Example 1, and the beaker on the left is the result in Comparative Example 1). Detailed Implementation
[0022] To facilitate understanding of the present invention, it will be described more fully and in detail below, but the scope of protection of the present invention is not limited to the following specific embodiments.
[0023] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.
[0024] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.
[0025] Example 1: 20g of β molecular sieve (silicon-to-aluminum ratio of 20) was immersed in 0.2mol / L cobalt nitrate aqueous solution at 25°C for 6h, filtered, and the immersed molecular sieve was dried at 80°C for 6h. Then it was placed in a muffle furnace for calcination at 400°C for 4h to obtain modified β molecular sieve with a cobalt content of 2.0%.
[0026] 20g of 4A molecular sieve was used to pre-dry 5L of isopropanol. The 4A molecular sieve was added to the isopropanol and stirred at 25℃ for 3 hours. After filtration, the water content of the resulting isopropanol was below 1000ppm, the carbonyl compound content was 188ppm, and the water solubility test showed slight turbidity. 20g of the modified β-molecular sieve was then packed into the middle section of a distillation column, and isopropanol was added to the reboiler. Distillation of the isopropanol was then initiated. The pressure during distillation was atmospheric pressure, the reboiler temperature was 80-100℃, the top temperature was 86℃, and the reflux ratio was 8. Samples were sent for gas chromatography analysis, and the carbonyl compound content was 44ppm. The water solubility test showed clear results; as shown in Figure 1 (right beaker).
[0027] Example 2: 20g of β molecular sieve (silicon-to-aluminum ratio of 20) was immersed in a 0.2mol / L copper nitrate aqueous solution at 30°C for 4 hours, filtered, and the immersed molecular sieve was dried at 90°C for 4 hours. Then it was placed in a muffle furnace for calcination at 450°C for 6 hours to obtain a modified β molecular sieve with a copper content of 1.8%.
[0028] 20g of 4A molecular sieve was used to pre-treat 5L of isopropanol by drying. The 4A molecular sieve was added to the isopropanol and stirred at 25℃ for 4 hours. After filtration, the water content of the resulting isopropanol was below 1000ppm, the carbonyl compound content was 185ppm, and the water solubility test showed slight turbidity. 20g of the modified β-molecular sieve was then packed into the middle section of a distillation column, and isopropanol was added to the reboiler. Distillation of the isopropanol was then initiated. The pressure during distillation was atmospheric pressure, the reboiler temperature was 80-100℃, the top temperature was 86℃, and the reflux ratio was 8. Samples were sent for gas chromatography analysis, and the carbonyl compound content was 42ppm. The water solubility test showed the product was clear.
[0029] Example 3: Based on Example 2, isopropanol was continuously distilled while the water solubility test results were monitored. When the isopropanol throughput reached 100 kg, the water solubility test results showed slight turbidity. Modified β-molecular sieves were removed from the distillation column packing for regeneration. The modified β-molecular sieves were soaked in ethanol for 4 hours, then transferred to a 70°C constant temperature water bath for evaporation, then purged with nitrogen in a 120°C drying oven for 6 hours, and finally calcined in a muffle furnace at 400°C for 6 hours. The regenerated modified β-molecular sieves were then repacked into the distillation column, and the water solubility test results of the distilled isopropanol were clear.
[0030] Example 4: Based on Example 2, the packing method of the distillation column was changed: the modified β molecular sieve was evenly divided into 3 parts and filled into the upper, middle and lower parts of the packing respectively, and then distillation was carried out. The pressure during distillation was atmospheric pressure, the bottom temperature was 80-100℃, the top temperature was 86℃, the reflux ratio was 8, and the sample was sent for gas chromatography analysis. The carbonyl compound content was 38ppm, and the water solubility test result was clear.
[0031] Comparative Example 1: Based on Example 2, the modified β-molecular sieve used for distillation was replaced with an unmodified β-molecular sieve, and isopropanol was distilled under the same distillation conditions. Samples were sent for gas chromatography analysis, and the carbonyl compound content was 172 ppm. The water solubility test showed slight turbidity; as shown in Figure 1 (left beaker).
[0032] Comparative Example 2: Based on Example 2, the modified β molecular sieve used for distillation was replaced with 4A molecular sieve, and isopropanol was distilled under the same distillation conditions. Samples were sent for gas chromatography analysis, and the carbonyl compound content was 180 ppm. The water solubility test results showed slight turbidity.
[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.
Claims
1. A method for removing water-insoluble carbonyl impurities from isopropanol, characterized in that: When industrial-grade isopropanol is distilled and separated, modified β-molecular sieves are added to the packing material in the distillation column; the modified β-molecular sieves account for 10-20% of the total packing mass.
2. The method according to claim 1, characterized in that: The distillation separation process is carried out under normal pressure, with the bottom temperature of the distillation column controlled at 80-100℃, the top temperature at 86℃, and the reflux ratio at 8-10.
3. The method according to claim 2, characterized in that: The modified β molecular sieve is arranged in the distillation column by dividing the modified β molecular sieve into three equal parts and filling them into the upper, middle and lower parts of the packing in the distillation column, respectively.
4. The method according to claim 3, characterized in that: The modified β-molecular sieve is a β-molecular sieve modified by metal ion impregnation; the metal content of the modified β-molecular sieve is 0.5-5%.
5. The method according to claim 4, characterized in that: The modified β molecular sieve is prepared by the following method: β molecular sieve with a silicon-to-aluminum ratio of 20-100 is immersed in a metal salt immersion solution at 10-40℃ for 2-8 hours, then filtered, dried, and then placed in a furnace at a calcination temperature of 400-600℃ for 2-6 hours to obtain the modified β molecular sieve.
6. The method according to claim 5, characterized in that: The metal salt impregnation solution is one or a mixture of several solutions selected from the following: a cobalt nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L, a cerium nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L, a copper nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L, and a nickel nitrate aqueous solution with a molar concentration of 0.1-1.0 mol / L.
7. The method according to claim 6, characterized in that: Before the industrial-grade isopropanol is subjected to distillation separation, it needs to be dried to ensure that the water content in the isopropanol is below 1000 ppm and the carbonyl compound content in the isopropanol is below 200 ppm.
8. The method according to claim 7, characterized in that: The drying pretreatment involves adding 4A molecular sieves to isopropanol, stirring at 25°C for 3-6 hours, and filtering to obtain isopropanol with a water content of less than 1000 ppm and a carbonyl compound content of less than 200 ppm.
9. The method according to claim 8, characterized in that: The industrial-grade isopropanol also includes the replacement or regeneration of the modified β molecular sieve during the distillation separation process. That is, when the water solubility test result of the treated isopropanol in the distillation column shows slight turbidity, the distillation is stopped, and then the modified β molecular sieve is taken out of the distillation column for replacement or regeneration.
10. The method according to claim 9, characterized in that: The regeneration process involves soaking the used modified β molecular sieve in ethanol for 2-8 hours, then transferring it to a constant temperature water bath at 60-100℃ to evaporate it to dryness, followed by purging with nitrogen in a drying oven at 100-150℃ for 2-8 hours, and finally calcining it in a muffle furnace at 400-600℃ for 2-6 hours to obtain the regenerated modified β molecular sieve.