Isopropanol and preparation method thereof

Abstract

The invention relates to the field of preparation of wet electronic chemicals required in a semiconductor manufacturing process, in particular to isopropanol and a preparation method thereof. The method comprises the following steps: carrying out light component removal treatment on an isopropanol raw material to obtain a first light component and a first heavy component; carrying out first rectification separation on the first light component to obtain a second light component and a second heavy component; returning the second heavy component to light component removal treatment; the second light component is partially or completely hydrotreated and subjected to gas-liquid separation, an obtained liquid phase is returned to be subjected to light component removal treatment, and a gas phase is returned to be subjected to hydrotreating treatment; the first heavy component is dehydrated and then subjected to heavy component removal treatment, and a third light component, a third heavy component and high-purity isopropanol are obtained; and returning the third light component to the light component removal treatment, and carrying out second rectification separation on the third heavy component to obtain a fourth light component and a fourth heavy component. The method has the advantages of good stability, high product recovery rate compared with the traditional process, high product purity, low water content and low metal ion residue, and can be used in the integrated circuit industry.

Description

Technical Field

[0001] The invention relates to the field of preparation of wet electronic chemicals required in a semiconductor manufacturing process, and in particular to isopropyl alcohol and a preparation method thereof. Background Art

[0002] Isopropyl alcohol is an important industrial solvent. It is widely used in pharmaceuticals, cosmetics, plastics and coatings because of its good solubility, low surface tension and toxicity, and good volatility characteristics.

[0003] Ultra-clean high-purity isopropyl alcohol is a high-purity, high-cleanliness product obtained after further processing based on industrial-grade isopropyl alcohol. It is mainly used in the fields of integrated circuits, flat panel displays, printed circuit boards, and photovoltaic cells, and is often used as a cleaning agent and dehydrating agent. Due to different usage scenarios, the product grade requirements for ultra-clean high-purity isopropyl alcohol are also different. Among them, the integrated circuit industry is the industry with the highest requirements for the product grade of ultra-clean high-purity isopropyl alcohol. It has very strict requirements on the purity, water content, metal ion residue, and particle size and residue of isopropyl alcohol. Moreover, with the further breakthroughs in semiconductor manufacturing processes, higher requirements will be placed on the product grade of ultra-clean high-purity isopropyl alcohol.

[0004] In recent years, with the development of international and domestic integrated circuit industries, the demand for ultra-clean high-purity isopropyl alcohol is very urgent. For this reason, research on the preparation method of ultra-clean high-purity isopropyl alcohol has received more and more attention. There are also many related reports at home and abroad, such as the document "Study on the Preparation Method of Ultra-Pure Isopropyl Alcohol" reports a method of using industrial-grade isopropyl alcohol as a raw material, adding anhydrous sodium carbonate and calcium hydride respectively, and then undergoing three-stage distillation, and finally using PVDF membrane separation and filtration to finally obtain high-purity isopropyl alcohol. In addition, as CN 102452897A uses industrial-grade isopropyl alcohol as a raw material, it successively undergoes molecular sieve dehydration, filtration, evaporation, distillation, ion exchange and other steps to finally obtain an ultra-clean high-purity isopropyl alcohol product with a purity of ≥99.99%, a water content of ≤100ppm, and a metal ion content of ≤100ppt. For example, CN 101362675B reports a method of removing metal by complexation, removing water by dehydration, removing microparticles by microfiltration, removing organic impurities by distillation, and finally removing ions by nanofiltration to finally obtain an ultra-clean high-purity isopropyl alcohol product. The above process has adopted a multi-stage distillation process. Although the removal efficiency of organic impurities is high, the recovery rate of the product will be greatly reduced, thereby improving the unit cost of ultra-clean high-purity isopropyl alcohol. Meanwhile, the product grade also needs to be further improved. Based on the above analysis, developing a method for preparing ultra-clean high-purity isopropyl alcohol with high efficiency, low consumption, high recovery rate and high quality and a system for preparing ultra-clean high-purity isopropyl alcohol are the important directions of research. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of low recovery rate, high energy consumption and poor product grade in the prior art, and to provide isopropyl alcohol and a preparation method thereof. The method provided by the present invention is not only simple to operate, energy-saving and has a high recovery rate, but also can produce high-quality ultra-clean high-purity isopropyl alcohol.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for preparing isopropanol, the method comprising: removing light components from an isopropanol raw material to obtain a first light component and a first heavy component;

[0007] The first light component is separated by a first distillation to obtain a second light component and a second heavy component; the second heavy component is returned to the light removal treatment; part or all of the second light component is subjected to hydrogenation treatment and gas-liquid separation, the obtained liquid phase is returned to the light removal treatment, and the gas phase is returned to the hydrogenation treatment;

[0008] The first heavy component is dehydrated and then subjected to a de-heavy treatment to obtain a third light component, a third heavy component and high-purity isopropanol; the third light component is returned to the de-light treatment, and the third heavy component is separated by a second distillation to obtain a fourth light component and a fourth heavy component.

[0009] A second aspect of the present invention provides high-purity isopropanol prepared by the preparation method.

[0010] Through the above technical solution, the present invention has the following advantages:

[0011] The method of the present invention has good stability, a higher product recovery rate than traditional processes, and a high product purity, low water content and low metal ion residues, and can be used in the integrated circuit industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention provides a schematic flow diagram of a method for preparing isopropanol in accordance with a specific embodiment of the present invention.

[0013] Description of Reference Numerals

[0014] ① Light removal tower 6, hydrogen

[0015] ②First distillation tower 7, hydrogenation product

[0016] ③ Catalytic hydrogenation unit 8, gas phase after gas-liquid separation

[0017] ④Gas-liquid separator 9, liquid phase after gas-liquid separation

[0018] ⑤ Dehydration adsorption device 10, light tower bottom liquid

[0019] ⑥Deweighting tower 11, dehydrated product

[0020] ⑦ Second distillation tower 12, deweighting tower top liquid

[0021] ⑧ Deionization device 13, deweighting tower bottom liquid

[0022] ⑨ De-particle device 14, second distillation tower bottom liquid

[0023] 1. Industrial grade isopropanol 15. Top liquid of the second distillation tower

[0024] 2. Light removal tower top liquid 16. Heavy removal tower measuring line produced liquid

[0025] 3. The bottom liquid of the first distillation tower 17, the product after deionization

[0026] 4. Top liquid of the first distillation tower (extracted) 18. Ultra-clean high-purity isopropanol

[0027] 5. Top liquid of the first distillation tower (hydrogenation) DETAILED DESCRIPTION

[0028] 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.

[0029] The invention provides a method for preparing isopropanol. The method comprises: performing light removal treatment on an isopropanol raw material to obtain a first light component and a first heavy component; performing first distillation separation on the first light component to obtain a second light component and a second heavy component; returning the second heavy component to the light removal treatment; performing hydrogenation treatment and gas-liquid separation on part or all of the second light component, returning the obtained liquid phase to the light removal treatment, and returning the gas phase to the hydrogenation treatment; performing heavy removal treatment on the first heavy component after dehydration to obtain a third light component, a third heavy component and high-purity isopropanol; returning the third light component to the light removal treatment, and performing second distillation separation on the third heavy component to obtain a fourth light component and a fourth heavy component.

[0030] According to a preferred embodiment of the present invention, 95.0-99.9wt%, preferably 99.0-99.9wt%, of the second light component is subjected to hydrogenation treatment. In addition to acetone enrichment, the first distillation separation system also contains a small amount of enriched methanol and non-condensable gas propylene. By adopting the aforementioned preferred scheme, the second light component is partially discharged so as not to accumulate in the system, thereby ensuring the stability of the product during the continuous operation of the system.

[0031] According to a preferred embodiment of the present invention, the method further comprises: the high-purity isopropyl alcohol is subjected to deionization and de-particle treatment.

[0032] According to a preferred embodiment of the present invention, the deionization treatment adopts ion exchange resin adsorption.

[0033] 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; preferably, the mass ratio of the hydrogen-type strongly acidic cation exchange resin and the hydroxide-type strongly basic anion exchange resin is 3:1-1:3. The charge in the solution is a state of conservation. When there are metal cations, there are anions. In order to better remove the cations, the anions must also be removed. Therefore, a mixed resin is used, in which the hydrogen-type strongly acidic cation exchange resin can remove the cations in the isopropanol product and the hydrogen ions, while the hydroxide-type strongly basic anion exchange resin can remove the anions in the isopropanol and the hydroxide ions, and finally the hydrogen ions and the hydroxide ions finally form water. Since the cation concentration after distillation is very low, the amount of water that can be formed is also very limited, which does not affect the water content in the product.

[0034] According to a preferred embodiment of the present invention, the demicronization treatment adopts membrane separation. The removal of microparticles adopts membrane separation, which can effectively remove microparticles in the isopropanol product through the pore size of the membrane separation to achieve the purpose of purification.

[0035] According to a preferred embodiment of the present invention, the demicronization process uses at least four, preferably four to six, membrane separations. For example, membranes with specifications of 200 nm, 100 nm, 50 nm and 30 nm are used for separation. The above-mentioned at least four-stage filtration can ensure that the particles (≥50 nm) in the final ultra-clean high-purity isopropanol product are ≤10 / ml.

[0036] According to a preferred embodiment of the present invention, the material of the membrane separation is at least one of PTFE, PVDF and PE. The above three membrane materials have good processing performance and low dissolution rate.

[0037] According to a preferred embodiment of the present invention, the fourth light component is returned for de-heavy treatment.

[0038] The present invention does not limit the composition and source of industrial-grade isopropyl alcohol. According to a preferred embodiment of the present invention, the content of isopropyl alcohol in the isopropyl alcohol raw material is not less than 98wt%.

[0039] According to a preferred embodiment of the present invention, the isopropanol raw material further contains at least one of water, n-propanol, isopropyl ether, acetone, methyl ethyl ketone, isobutanol and ethylbenzene.

[0040] According to a preferred embodiment of the present invention, the dehydration method is adsorption dehydration. This dehydration method does not require the addition of a third component and does not introduce impurities.

[0041] According to a preferred embodiment of the present invention, the adsorption and dehydration material is a molecular sieve membrane and / or a molecular sieve, preferably a NaA type pervaporation molecular sieve membrane and / or an A type molecular sieve. The NaA type pervaporation molecular sieve membrane has good permeability to the water in the isopropanol, so that the water content on the concentrated side is low; the A type molecular sieve has good water removal ability and a large saturated adsorption capacity, and can remove the water in the isopropanol to a very low limit.

[0042] According to a preferred embodiment of the present invention, the type A molecular sieve includes type 4A molecular sieve and / or type 5A molecular sieve. Type 4A molecular sieve and type 5A molecular sieve have good adsorption and dehydration capabilities, and also have a certain adsorption capacity for small molecular light component organic impurities, which can ensure that there are no light components in the product after light removal.

[0043] According to a preferred embodiment of the present invention, the catalyst for hydrogenation treatment is a copper-based catalyst. By adopting the above preferred scheme, it has the characteristics of high catalytic efficiency, high conversion rate of acetone, high selectivity of isopropanol, etc.

[0044] According to a preferred embodiment of the present invention, the conditions for the light component removal treatment include: a pressure of 130-200 kPa, and / or a reflux ratio of 2-20, and / or a bottom operating temperature of 86.5-100.7°C. By adopting the aforementioned preferred scheme, a better light component removal efficiency can be guaranteed, and operation under this pressure condition is conducive to ensuring that moisture and other organic impurities in the environment do not enter the light component removal system, thereby contaminating the product. At the same time, the boiling point difference between the light component and isopropanol can be widened, making the light component removal cleaner, and is also conducive to the integrated use of heat. This high-grade heat can be used to heat other processes to improve heat utilization.

[0045] According to a preferred embodiment of the present invention, the conditions of the de-weighting treatment include: a pressure of 101-150 kPa, and / or a reflux ratio of 0.2-5, and / or a bottom operating temperature of 82.5-92.8° C. By adopting the aforementioned preferred scheme, it is possible to ensure more complete removal of heavy components, ensure the recovery rate of the de-weighting treatment, and at the same time ensure that water and other organic impurities outside the environmental system do not enter the de-weighting system, thereby ensuring the quality of the de-weighting product.

[0046] According to a preferred embodiment of the present invention, the pressure of the de-heavy process is lower than that of the light process, preferably 30-50 kPa lower. By adopting the above preferred solution, the liquid produced after light removal can be used to heat the de-heavy system, so as to make full use of the heat.

[0047] According to a preferred embodiment of the present invention, the conditions of the first distillation separation include: a pressure of 50-101 kPa, a reflux ratio of 0.2-2, and / or a bottom operating temperature of 66.0-82.5°C. By adopting the aforementioned preferred scheme, the light components in the light-removing logistics can be further enriched. Under this condition, it can be ensured that some light components and non-condensable gases in the system, such as acetone and propylene, are discharged as completely as possible. At the same time, the use of negative pressure (lower than normal pressure) can also make the vapor phase logistics after light removal be used to heat the first distillation separation system, thereby improving the utilization rate of heat.

[0048] According to a preferred embodiment of the present invention, the conditions for the second distillation separation include: a pressure of 50-101 kPa, a reflux ratio of 0.2-2, and / or a bottom operating temperature of 66.5-83.0°C. By adopting the aforementioned preferred scheme, the liquid phase logistics after the de-weighting treatment can be further enriched. Under this (negative pressure, low reflux ratio) condition, it can be ensured that the content of the heavy component in the second distillation separation product meets the requirements, and the recovery rate can be guaranteed, thereby improving the overall recovery rate of isopropanol.

[0049] According to a preferred embodiment of the present invention, the conditions of the hydrotreatment include: a space velocity of 0.2-0.8h -1 , and / or the molar ratio of hydrogen to the second light component is 2-10, and / or the reaction temperature is 80-120°C, and / or the pressure is 3-10MPa. Under the hydrogenation conditions, it has good characteristics of acetone catalytic hydrogenation to isopropanol, and can reduce the 2000-5000ppm of acetone in the feed to less than 100ppm at the discharge port. Studies have found that under high temperature and long-term conditions, isopropanol will undergo a reverse reaction to generate acetone, causing the acetone content in isopropanol to increase during the distillation process, which will eventually affect the quality of the product. In order to improve the recovery rate of industrial-grade isopropanol, adding an acetone catalytic hydrogenation unit after the first distillation tower can effectively reduce the acetone content, so that the feed liquid in the first distillation separation process can be reused, and the recovery rate of ultra-clean high-purity isopropanol can be improved.

[0050] The invention provides high-purity isopropyl alcohol prepared by the preparation method, wherein the purity of the isopropyl alcohol is above 99.995%, the water content is ≤50ppm, and the acetone content is ≤3ppm; more preferably, the purity of the isopropyl alcohol is above 99.997wt%.

[0051] According to a preferred embodiment of the present invention, the single metal ion (any metal ion) in the high-purity isopropanol is ≤10ppt, and the particles with a size of ≥50nm are ≤10 / ml. The types of metal ions vary depending on the source of the raw materials, and the common ones are sodium, potassium, calcium, iron, etc.

[0052] like Figure 1As shown, the present invention provides an exemplary description of a preferred embodiment, and the illustrated device includes:

[0053] The top gas phase discharge port of the light-removal tower ① is connected to the feed port of the first distillation tower ②, the top material outlet of the first distillation tower ② is connected to the outside of the device and to the lower feed port of the catalytic hydrogenation device, the upper discharge port of the catalytic hydrogenation device ③ is connected to the gas-liquid separator ④, the top discharge port of the gas-liquid separator ④ is connected to the lower feed port of the catalytic hydrogenation device ③, and the bottom of the gas-liquid separator ④ is connected to the raw material feed port of the light-removal tower ①. The bottom of the light-removing tower ① is connected to the lower end of the dehydration adsorption device ⑤, the upper end of the dehydration adsorption device ⑤ is connected to the feed port of the heavy-removing tower ⑥, the top discharge port of the heavy-removing tower ⑥ is connected to the side-line feed port of the light-removing tower ①, the side-line discharge port of the heavy-removing tower ⑥ is connected to the deionizing device ⑧ and the micro-particle removal device ⑨ in sequence, and the bottom discharge port of the heavy-removing tower ⑥ is connected to the feed port of the second distillation tower ⑦, the top discharge port of the second distillation tower ⑦ is connected to the feed port of the heavy-removing tower ⑥, and the bottom discharge port of the second distillation tower ⑦ is connected to the outside of the device.

[0054] The preparation process of isopropyl alcohol includes:

[0055] Industrial isopropanol 1 first enters a light-removing tower ① to obtain (a first light component) a light-removing tower top liquid 2 and (a first heavy component) a light-removing tower bottom liquid 10. The first light component enters a first distillation tower ②, and the obtained (a second heavy component) a first distillation tower bottom liquid 3 is returned to the light-removing tower ① for feeding, while part of the obtained second light component (the first distillation tower top liquid (extraction) 4) is discharged out of the boundary, and part (the first distillation tower top liquid (hydrogenation) 5) enters a catalytic hydrogenation device ③ to contact with hydrogen 6 for hydrogenation, and the hydrogenated product 7 is sent to a gas-liquid separator ④, and the obtained liquid phase 9 after gas-liquid separation is returned to the light-removing tower ①, and the gas phase 8 after gas-liquid separation is returned to the catalytic hydrogenation device ③. The first heavy component obtained from the bottom of the light-removing tower ① is passed through a dehydration adsorption device ⑤ and then enters a heavy-removing tower ⑥. The top of the tower obtains (the third light component) heavy-removing tower top liquid 12, which is returned to the light-removing tower ①, and the side line obtains the heavy-removing tower line production liquid 16, which is passed through a deionizing device ⑧ to obtain a deionized product 17. The deionized product 17 is passed through a microparticle removal device ⑨ to obtain an ultra-clean high-purity isopropanol 18 product, and the bottom liquid 13 of the heavy-removing tower enters the second distillation tower ⑦, and the top of the tower obtains (the fourth light component) the top liquid 15 of the second distillation tower, which is returned to the heavy-removing tower ⑥, and the bottom of the tower obtains (the fourth heavy component) the second distillation tower bottom liquid 14, which is discharged out of the boundary.

[0056] In the present invention, the "tower top, upper end, top" refers to the "0-30%" part of the volume of each device from top to bottom; "tower bottom, lower end, bottom" refers to the "70-100%" part of the volume of each device from top to bottom.

[0057] The following will be through examples (in Figure 1The present invention is described in detail in the device shown in FIG. The reagents and raw materials used in the present invention are all commercially available.

[0058] In the present invention, the catalysts used in the examples and comparative examples are the same copper-based catalysts, 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.

[0059] Example 1

[0060] A batch of industrial-grade isopropanol was measured to have a purity of 99.1% by weight and a water content of 750ppm, including 470ppm of acetone. It was pumped into a light-removal tower with an operating pressure of 180kPa and a reflux ratio of 15. At this time, the operating temperature of the bottom of the light-removal tower was 97.7°C; after separation in the light-removal tower, the top product entered the first distillation tower. The operating pressure of the first distillation tower was 75kPa, and the reflux ratio was 0.8. At this time, the operating temperature of the bottom of the first distillation tower was 75.6°C. After separation in the first distillation tower, the bottom product returned to the light-removal tower. Part of the top product of the first distillation tower was directly discharged out of the boundary area, and part was pressurized and catalytically hydrogenated together with hydrogen (the catalyst was a copper-based catalyst, the same below). The mass ratio of the discharge out of the boundary and the entry into the catalytic hydrogenation was 3%:97%. Catalytic hydrogenation was carried out at an air velocity of 0.6h -1 , hydrogen / feed is 8 (molar ratio), reaction temperature is 110°C, and pressure is 6MPa. After the above catalytic hydrogenation process, the acetone content in the top product of the first distillation tower can be reduced from 4900ppm to below 80ppm. After separation of the hydrogenated gas-liquid mixed product, the gas phase product returns to the hydrogen feed port for reuse, while the liquid phase crude product enters the light removal tower together with the industrial grade isopropanol.

[0061] The produced liquid from the bottom of the light removal tower is dehydrated, and 5A molecular sieve is used for dehydration. After dehydration, the product enters the de-weighting tower. The operating pressure of the de-weighting tower is 105kPa, and the reflux ratio is 1. At this time, the operating temperature of the bottom of the de-weighting tower is 83.7℃. After being treated in the de-weighting tower, the bottom product of the de-weighting tower enters the second distillation tower. The top product of the de-weighting tower enters the light removal tower. The bottom product of the de-weighting tower entering the second distillation tower has an operating pressure of 75kPa and a reflux ratio of 1 in the second distillation tower. At this time, the bottom operating temperature of the second distillation tower is 75.6℃. After separation in the second distillation tower, the bottom obtains an isopropanol product with a high content of heavy components, and the top product is combined with the feed of the de-weighting tower after dehydration and enters the de-weighting tower.

[0062] The side product of the de-weighting tower is successively subjected to ion exchange deionization and membrane separation de-particle removal to obtain an ultra-clean high-purity isopropyl alcohol product. The deionization adopts mixed bed resin and the membrane separation material uses PTFE. After four-stage filtration at 200nm, 100nm, 50nm and 30nm, ultra-clean high-purity isopropyl alcohol is obtained. The purity of the product can reach more than 99.999%, the acetone content is 1.2ppm, the water content is 36ppm, the recovery rate is 92.5%, the single metal ion in the product is ≤10ppt, and the particles (≥50nm) are ≤10 / ml.

[0063] Example 2

[0064] A batch of industrial-grade isopropanol was measured to have a purity of 98.2% by weight and a water content of 5600ppm, including 2000ppm of acetone. It was pumped into a light-removing tower with an operating pressure of 200kPa and a reflux ratio of 10. At this time, the operating temperature of the bottom of the light-removing tower was 100.7°C; after separation in the light-removing tower, the top product entered the first distillation tower. The operating pressure of the first distillation tower is 100kPa, and the reflux ratio is 1.5. At this time, the operating temperature of the bottom of the first distillation tower is 82.5°C. After separation in the first distillation tower, the bottom product returns to the light-removing tower. Part of the top product of the first distillation tower is directly discharged out of the boundary area, and part is pressurized and catalytically hydrogenated together with hydrogen. The mass ratio of the discharge out of the boundary and the entry into the catalytic hydrogenation is 4%:96%. Catalytic hydrogenation at an air velocity of 0.7h -1 , hydrogen / feed is 10 (molar ratio), reaction temperature is 110°C, and pressure is 8MPa. After the above catalytic hydrogenation process, the acetone content in the top product of the first distillation tower can be reduced from 52000ppm to below 100ppm. After separation of the hydrogenated gas-liquid mixed product, the gas phase product returns to the hydrogen feed port for reuse, while the liquid phase crude product enters the light removal tower together with the industrial grade isopropanol.

[0065] The produced liquid from the bottom of the light removal tower is dehydrated, and 4A molecular sieve is used for dehydration. After dehydration, the product enters the de-weighting tower. The operating pressure of the de-weighting tower is 150kPa, and the reflux ratio is 2. At this time, the operating temperature of the bottom of the de-weighting tower is 92.8℃. After being treated by the de-weighting tower, the bottom product of the de-weighting tower enters the second distillation tower. The top product of the de-weighting tower enters the light removal tower. The bottom product of the de-weighting tower entering the second distillation tower has an operating pressure of 100kPa and a reflux ratio of 2 in the second distillation tower. At this time, the bottom operating temperature of the second distillation tower is 82.5℃. After separation in the second distillation tower, the bottom obtains an isopropanol product with a high content of heavy components, and the top product is combined with the feed of the de-weighting tower after dehydration and enters the de-weighting tower.

[0066] The side product of the de-weighting tower is successively subjected to ion exchange deionization and membrane separation de-particle removal to obtain an ultra-clean high-purity isopropyl alcohol product. The deionization adopts mixed bed resin and the membrane separation material uses PTFE. After four-stage filtration at 200nm, 100nm, 50nm and 30nm, ultra-clean high-purity isopropyl alcohol is obtained. The purity of the product can reach more than 99.997%, the acetone content is 1.8ppm, the water content is 45ppm, the recovery rate is 90.7%, the single metal ion in the product is ≤10ppt, and the particles (≥50nm) are ≤10 / ml.

[0067] Example 3

[0068] The same as Example 1, except that the operating pressure of the lightness removal tower is 130 kPa, and the operating temperature of the bottom of the lightness removal tower is controlled to 88.4°C.

[0069] The ultra-clean high-purity isopropyl alcohol finally obtained has a product purity of up to 99.997%, an acetone content of 1.8 ppm, a water content of 38 ppm, a recovery rate of 92.0%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0070] Example 4

[0071] The same as Example 1, except that 100% of the top product of the first rectification tower enters the catalytic hydrogenation device.

[0072] The ultra-clean high-purity isopropyl alcohol finally obtained has a product purity of up to 99.995%, an acetone content of 1.5 ppm, a water content of 47 ppm, a recovery rate of 93.5%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0073] Example 5

[0074] Same as Example 1, except that the isopropanol content in the isopropanol raw material is 97.5%, the water content is 1.3%, and the acetone content is 3200ppm.

[0075] The ultra-clean high-purity isopropyl alcohol finally obtained has a product purity of up to 99.995%, an acetone content of 2.9 ppm, a water content of 50 ppm, a recovery rate of 89.3%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0076] Example 6

[0077] Same as Example 1, except that the reflux ratio of the lightness removal tower is 0.5.

[0078] The ultra-clean high-purity isopropyl alcohol finally obtained has a product purity of up to 99.998%, an acetone content of 1.9 ppm, a water content of 34 ppm, a recovery rate of 88.2%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0079] Example 7

[0080] The same as Example 1, except that the operating pressure of the deweighting tower is 75 kPa, and the corresponding operating temperature of the deweighting tower kettle is 75.6°C.

[0081] The ultra-clean high-purity isopropanol finally obtained has a product purity of up to 99.995%, an acetone content of 2.7 ppm, a water content of 42 ppm, a recovery rate of 92.2%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0082] Example 8

[0083] Same as Example 1, except that the operating pressure of the first distillation tower is 125 kPa, the operating temperature of the tower bottom is 87.8°C, and the operating pressure of the second distillation tower is 125 kPa, the operating temperature of the tower bottom is 87.7°C.

[0084] The ultra-clean high-purity isopropyl alcohol finally obtained has a product purity of up to 99.995%, an acetone content of 2.0 ppm, a water content of 40 ppm, a recovery rate of 92.6%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0085] Comparative Example 1

[0086] The same as Example 1, except that there is no catalytic hydrogenation device, a part of the top product of the first distillation tower is discharged out of the boundary, and the original hydrogenated part is directly returned to the light removal tower.

[0087] The ultra-clean high-purity isopropanol finally obtained has a product purity of up to 99.982%, an acetone content of 7.2 ppm, a water content of 53 ppm, a recovery rate of 91.3%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0088] Comparative Example 2

[0089] The same as Example 1, except that there is no second distillation tower, and the bottom product of the deweighting tower is directly discharged outside the boundary.

[0090] The ultra-clean high-purity isopropyl alcohol finally obtained has a product purity of up to 99.998%, an acetone content of 1.5 ppm, a water content of 48 ppm, a recovery rate of 85.1%, a single metal ion of ≤10 ppt, and particles (≥50 nm) of ≤10 / ml.

[0091] 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 preparing isopropanol, characterized in that: The method comprises: performing light removal treatment on an isopropanol raw material to obtain a first light component and a first heavy component; The first light component is separated by a first distillation to obtain a second light component and a second heavy component; the second heavy component is returned to the light removal treatment; part or all of the second light component is subjected to hydrogenation treatment and gas-liquid separation, the obtained liquid phase is returned to the light removal treatment, and the gas phase is returned to the hydrogenation treatment; The first heavy component is dehydrated and then subjected to a de-heavy treatment to obtain a third light component, a third heavy component and high-purity isopropanol; the third light component is returned to the de-light treatment, and the third heavy component is separated by a second distillation to obtain a fourth light component and a fourth heavy component.

2. The preparation method according to claim 1, wherein 95.0-99.9wt%, preferably 99.0-99.9wt% of the second light component is hydrotreated.

3. The preparation method according to claim 1 or 2, wherein: The method further comprises: the high-purity isopropyl alcohol is subjected to deionization and de-particle treatment; preferably The deionization treatment adopts the method of ion exchange resin adsorption; preferably, the ion exchange resin is a mixed resin comprising hydrogen-type strongly acidic cation exchange resin and hydroxide-type strongly basic anion exchange resin; more preferably, the mass ratio of hydrogen-type strongly acidic cation exchange resin to hydroxide-type strongly basic anion exchange resin is 3:1-1:3; and / or The demicronization treatment adopts membrane separation; preferably, at least four-stage membrane separation is adopted; more preferably, the material of the membrane separation is at least one of PTFE, PVDF and PE; and / or The fourth light component is returned to the de-heavy treatment.

4. The preparation method according to any one of claims 1 to 3, wherein The content of isopropanol in the isopropanol raw material is not less than 98wt%; Preferably, the isopropanol raw material further contains at least one of water, n-propanol, isopropyl ether, acetone, methyl ethyl ketone, isobutanol and ethylbenzene.

5. The preparation method according to any one of claims 1 to 4, wherein: The dehydration method is adsorption dehydration, and the adsorption dehydration material is preferably a molecular sieve membrane and / or a molecular sieve, more preferably a NaA type pervaporation molecular sieve membrane and / or an A type molecular sieve; and / or The catalyst for hydrogenation treatment is a copper-based catalyst.

6. The preparation method according to any one of claims 1 to 5, wherein: The conditions for the light removal treatment include: a pressure of 130-200 kPa, and / or a reflux ratio of 2-20, and / or a bottom operating temperature of 86.5-100.7° C.; and / or The conditions of the de-weighting treatment include: a pressure of 101-150 kPa, and / or a reflux ratio of 0.2-5, and / or a bottom operating temperature of 82.5-92.8°C; Preferably, the pressure of the de-heavy treatment is lower than that of the light treatment, more preferably 30-50 kPa lower.

7. The preparation method according to any one of claims 1 to 6, wherein: The conditions of the first distillation separation include: a pressure of 50-101 kPa, a reflux ratio of 0.2-2, and / or a bottom operating temperature of 66.0-82.5° C.; and / or The conditions for the second distillation separation include: a pressure of 50-101 kPa, a reflux ratio of 0.2-2, and / or a bottom operating temperature of 66.5-83.0°C.

8. The preparation method according to any one of claims 1 to 7, wherein: The conditions of the hydrotreatment include: space velocity 0.2-0.8h -1 , and / or the hydrogen / second light component molar ratio is 2-10, and / or the reaction temperature is 80-120°C, and / or the pressure is 3-10MPa.

9. High-purity isopropanol prepared by the preparation method described in any one of claims 1 to 8.

10. The high-purity isopropyl alcohol according to claim 9, wherein The purity of the high-purity isopropyl alcohol is above 99.995%, the water content is ≤50ppm, and the acetone content is ≤3ppm; Preferably, the single metal ion in the high-purity isopropanol is ≤10 ppt, and the particles with a size of ≥50 nm are ≤10 / ml.

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