A purification process for high-purity isopropanol

Abstract

The present application relates to the technical field of isopropanol processing, and specifically discloses a purification process for high-purity isopropanol; a purification process for high-purity isopropanol, comprising the following specific steps: mixing a crude isopropanol product with a phosphate buffer solution and distilling the mixture to obtain a preliminary purified material, subjecting the primary purified material to molecular sieve adsorption and water-absorbing resin dehydration in sequence, subjecting the isopropanol dehydrated by the resin to a reverse osmosis membrane to obtain a secondary isopropanol solution, and subjecting the secondary isopropanol solution to rectification treatment to obtain high-purity isopropanol; the pH value of the phosphate buffer solution is 7-8; the present application improves the phase separation of isopropanol and an aqueous phase by using a phosphate buffer solution, and combines the process with molecular sieve adsorption, water-absorbing resin dehydration, and reverse osmosis membrane treatment to remove the impurity content in the isopropanol and improve the purity of the isopropanol.

Description

Technical Field

[0001] The present application relates to the technical field of isopropyl alcohol processing, and in particular to a purification process for high-purity isopropyl alcohol. Background Art

[0002] With the rapid development of semiconductor and microelectronics industries, the demand for high-purity electronic chemicals is increasing. As an important microelectronics chemical, high-purity isopropyl alcohol is widely used in cleaning and drying in semiconductor and large-scale integrated circuit assembly and processing. The purity of isopropyl alcohol is crucial to product yield and performance.

[0003] At present, the common method for purifying high-purity isopropyl alcohol is mainly distillation. Multiple distillations can effectively remove low-boiling impurities and improve the purity of isopropyl alcohol. The content of isopropyl alcohol obtained reaches 99.9%. However, although the single distillation method is simple to operate, it is difficult to completely remove certain trace impurities and water. The water content in the obtained isopropyl alcohol is in the range of 500-1000ppm. The water content is too high, the cost of water removal is high, and post-processing is difficult. Summary of the invention

[0004] In order to reduce the moisture content and impurity content of the isopropyl alcohol product, the present application provides a purification process for high-purity isopropyl alcohol.

[0005] The present application provides a purification process for high-purity isopropanol, which adopts the following technical scheme: A purification process for high-purity isopropanol comprises the following specific steps: The crude isopropanol product is mixed with a phosphate buffer solution and distilled to obtain a preliminary purified material, the primary purified material is sequentially subjected to molecular sieve adsorption and water-absorbing resin dehydration, the isopropanol dehydrated by the resin is passed through a reverse osmosis membrane to obtain a secondary isopropanol solution, the secondary isopropanol solution is distilled to obtain high-purity isopropanol; the pH of the phosphate buffer solution is 7-8.

[0006] By adopting the above technical scheme, the phosphate buffer solution with a pH of 7-8 can provide a stable pH environment, help control the chemical balance in the distillation process, promote the precipitation or dissolution of impurities, thereby improving the purity of isopropanol. By adjusting the pH value of the phosphate buffer solution, the solubility of impurities can be changed to form insoluble salts to make impurities easier to separate from isopropanol. The crude isopropanol product is mixed with the phosphate buffer solution and then distilled. During the distillation process, the addition of the phosphate buffer solution can improve the phase separation of isopropanol and the aqueous phase, ensure a clearer phase interface, and facilitate subsequent liquid separation operations. At the same time, in the conventional isopropanol purification process, water and isopropanol may form an azeotrope, which is difficult to separate by simple distillation. The addition of the phosphate buffer solution can break this azeotropic relationship, making it easier to separate water and isopropanol, thereby reducing the water content in the isopropanol and improving the purity of isopropanol.

[0007] Preferably, the concentration of the phosphate buffer solution is 0.05-0.15 mol / L.

[0008] Preferably, when the isopropanol passes through the reverse osmosis membrane, the reverse osmosis pressure is 2-2.8 MPa and the permeation rate is 400-600 L / h.

[0009] By adopting the above technical solution, the reverse osmosis membrane can effectively remove soluble impurities such as metal ions and small organic molecules in the isopropyl alcohol solution, further improving the purity of the isopropyl alcohol. Under high pressure, the reverse osmosis membrane can selectively allow water molecules to pass through while blocking most impurities, thereby achieving precise control of the water content in the isopropyl alcohol, facilitating the subsequent precise reduction of the water content and improving the purity of the isopropyl alcohol.

[0010] Preferably, the temperature during the molecular sieve adsorption treatment is 30-40° C., and the molecular sieve adsorption treatment time is 1.5-2.5 h.

[0011] By adopting the above technical solution, within the temperature range of 30-40°C, the molecular sieve has highly selective adsorption characteristics, which can effectively remove specific impurities such as water, organic acids, and alcohols in isopropanol, which have not been completely removed in the previous distillation and buffer solution treatment, thereby improving the purity of isopropanol. The adsorption treatment time of 1.5-2.5h ensures that the molecular sieve is fully in contact with the isopropanol solution and reaches adsorption equilibrium, thereby achieving maximum removal of impurities and improving the purity of isopropanol.

[0012] Preferably, the molecular sieve is modified with phosphoric acid, and the modification method comprises the following specific steps: adding the molecular sieve into a phosphoric acid aqueous solution, stirring for 1-2 hours, filtering and drying at 100-120° C., and then calcining at 500-600° C. for 3-4 hours to obtain a modified molecular sieve.

[0013] By adopting the above technical scheme, phosphoric acid is used to modify the molecular sieve, which can reduce the weak acid amount of the molecular sieve, increase the acid amount of medium-strong acid and strong acid, increase the acidity of the molecular sieve, and then improve the molecular sieve's adsorption capacity for water molecules. The acid sites can form stronger interactions with water molecules, thereby promoting the adsorption and desorption of water molecules, reducing the content of water molecules in the isopropanol product, and increasing the content of isopropanol. During the high-temperature roasting process, phosphoric acid combines with the skeleton structure of the molecular sieve to form a more stable structure, improve the stability of the molecular sieve at high temperatures, facilitate the molecular sieve to be difficult to decompose in the subsequent high-temperature adsorption and regeneration process, improve the thermal stability and chemical stability of the molecular sieve, extend the service life of the molecular sieve in the adsorption process, reduce the replacement frequency, and reduce production costs.

[0014] Preferably, the water-absorbing resin comprises the following raw materials in parts by weight: 0.1-0.5 parts of initiator, 0.05-0.15 parts of cross-linking agent, 40-50 parts of acrylic acid, 20-30 parts of sodium p-styrene sulfonate, and 10-15 parts of polyvinyl alcohol.

[0015] By adopting the above technical scheme, the sodium styrene sulfonate has unsaturated double bonds, strong anionicity, thermal stability and hydrophilic functional groups, and the polyvinyl alcohol contains a large number of hydrophilic groups. Under the action of a crosslinking agent and an initiator, the polyvinyl alcohol, acrylic acid and the sodium styrene sulfonate undergo condensation and crosslinking reactions to form a three-dimensional network structure, which can wrap water molecules inside the network, so that the prepared water-absorbing resin has better water absorption and water retention effects and reduces the water content of isopropyl alcohol.

[0016] Preferably, the water-absorbing resin raw material also includes 3-5 parts of sodium carboxymethyl cellulose.

[0017] By adopting the above technical scheme, the sodium carboxymethyl cellulose polymer chain contains a large number of hydrophilic hydroxyl and carboxyl groups, has multi-capillary properties and a large specific surface area, increases the spatial network cross-linking points, and forms a larger network structure with the sodium p-styrene sulfonate and acrylic acid in the water-absorbent resin system, which can absorb and retain moisture, thereby improving the water absorption capacity of the water-absorbent resin system and reducing the water content of isopropyl alcohol.

[0018] Preferably, the method for preparing the water-absorbing resin comprises the following specific steps: Acrylic acid is diluted with water, and then sodium hydroxide is used to adjust the neutralization degree of acrylic acid, sodium carboxymethyl cellulose, sodium p-styrene sulfonate, and polyvinyl alcohol are added and mixed, and stirred evenly, a cross-linking agent is added, and the mixture is heated to 60-70° C., an initiator is added to react, and the product is dried and crushed to obtain a water-absorbing resin.

[0019] In summary, this application has the following beneficial effects: 1. Since the present application uses a phosphate buffer solution to be mixed with the crude isopropanol in advance, the chemical equilibrium in the distillation process is controlled, the phase separation of isopropanol and the aqueous phase is improved, and the water molecules are effectively separated from the isopropanol, thereby reducing the water content in the isopropanol and improving the purity of the isopropanol.

[0020] 2. In this application, phosphoric acid is used to modify the molecular sieve, increase the acidity of the molecular sieve, improve the molecular sieve's ability to adsorb water, reduce the water content in isopropyl alcohol, and improve the purity of isopropyl alcohol. Polyvinyl alcohol with a large number of hydrophilic groups is used with acrylic acid and sodium p-styrene sulfonate to form a three-dimensional network structure, which can wrap water molecules inside the network to achieve the effect of water absorption and water retention, thereby reducing the water content in isopropyl alcohol and improving the purity of isopropyl alcohol. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments.

[0022] All raw materials in the examples are commercially available. Example

[0023] Example 1 This embodiment provides a purification process for high-purity isopropanol, comprising the following specific steps: S1: Mix the crude isopropanol product with a phosphate buffer solution, wherein the phosphate buffer solution is an aqueous solution of sodium dihydrogen phosphate, the concentration of the phosphate buffer solution is 0.1 mol / L, and the pH of the phosphate buffer solution is 7.3, and then distill to obtain a preliminarily purified material.

[0024] S2: The primary purified material is treated with molecular sieve adsorption at a temperature of 35°C for 2 hours. The molecular sieve is Hβ molecular sieve purchased from the catalyst plant of Nankai University. The isopropanol treated with molecular sieve adsorption is then treated with a water-absorbent resin. The water-absorbent resin is purchased from SAP water-absorbent resin with a particle size range of 30-80 mesh.

[0025] S3: The isopropyl alcohol dehydrated by the water-absorbing resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2.5 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution, which is distilled to obtain high-purity isopropyl alcohol with a purity of 99.99%.

[0026] Example 2 This embodiment provides a purification process for high-purity isopropanol, comprising the following specific steps: S1: Mix the crude isopropanol product with a phosphate buffer solution, wherein the phosphate buffer solution is an aqueous solution of sodium dihydrogen phosphate, the concentration of the phosphate buffer solution is 0.1 mol / L, and the pH of the phosphate buffer solution is 7.3, and then distill to obtain a preliminarily purified material.

[0027] S2: The primary purified material is treated with molecular sieve adsorption at room temperature for 2 hours. The molecular sieve is Hβ molecular sieve purchased from the catalyst factory of Nankai University. The isopropanol treated with molecular sieve adsorption is then treated with a water-absorbent resin. The water-absorbent resin is selected from SAP water-absorbent resin with a particle size range of 30-80 mesh.

[0028] S3: The isopropyl alcohol dehydrated by the water-absorbing resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2.5 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution, which is distilled to obtain high-purity isopropyl alcohol with a purity of 99.99%.

[0029] Example 3 This embodiment provides a purification process for high-purity isopropanol, comprising the following specific steps: S1: Mix the crude isopropanol product with a phosphate buffer solution, wherein the phosphate buffer solution is an aqueous solution of sodium dihydrogen phosphate, the concentration of the phosphate buffer solution is 0.1 mol / L, and the pH of the phosphate buffer solution is 7.3, and then distill to obtain a preliminarily purified material.

[0030] S2: The primary purified material is treated with molecular sieve adsorption at a temperature of 35°C for 2 hours. The molecular sieve is Hβ molecular sieve purchased from the catalyst factory of Nankai University. The isopropanol treated with molecular sieve adsorption is then treated with a water-absorbent resin. The water-absorbent resin is purchased from SAP water-absorbent resin with a particle size range of 30-80 mesh.

[0031] S3: The isopropyl alcohol dehydrated by the water-absorbing resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution, which is distilled to obtain high-purity isopropyl alcohol with a purity of 99.99%.

[0032] Example 4 The embodiment provides a purification process of high-purity isopropanol, comprising the following specific steps: S1: Mix the crude isopropanol product with a phosphate buffer solution, wherein the phosphate buffer solution is an aqueous solution of sodium dihydrogen phosphate, the concentration of the phosphate buffer solution is 0.1 mol / L, and the pH of the phosphate buffer solution is 7.3, and then distill to obtain a preliminarily purified material.

[0033] S2: Mix Hβ molecular sieve with phosphoric acid aqueous solution, Hβ molecular sieve is purchased from Nankai University Catalyst Factory, the concentration of phosphoric acid aqueous solution is 1 mol / L, the mass ratio of Hβ molecular sieve to phosphoric acid aqueous solution is 1:4, stir at room temperature for 1 hour, filter and wash, dry at 110°C, and calcine at 550°C for 3.5 hours to obtain a modified molecular sieve; the primary purified material is subjected to adsorption treatment with the modified molecular sieve, the treatment temperature is 35°C, and the modified molecular sieve adsorption time is 2 hours; the isopropanol after the modified molecular sieve adsorption treatment is then treated with a water-absorbent resin, and the water-absorbent resin is selected from SAP water-absorbent resin with a particle size range of 30-80 mesh.

[0034] S3: The isopropyl alcohol dehydrated by the water-absorbing resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2.5 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution, which is distilled to obtain high-purity isopropyl alcohol with a purity of 99.99%.

[0035] Example 5 This embodiment provides a purification process for high-purity isopropanol, comprising the following specific steps: S1: Mix the crude isopropanol product with a phosphate buffer solution, wherein the phosphate buffer solution is an aqueous solution of sodium dihydrogen phosphate, the concentration of the phosphate buffer solution is 0.1 mol / L, and the pH of the phosphate buffer solution is 7.3, and then distill to obtain a preliminarily purified material.

[0036] S2: Mix Hβ molecular sieve with phosphoric acid aqueous solution. Hβ molecular sieve was purchased from the catalyst factory of Nankai University. The concentration of phosphoric acid aqueous solution was 1 mol / L. The mass ratio of Hβ molecular sieve to phosphoric acid aqueous solution was 1:4. Stir at room temperature for 1 hour, filter and wash, dry at 110°C, and calcine at 550°C for 3.5 hours to obtain a modified molecular sieve. The primary purified material was subjected to adsorption treatment with the modified molecular sieve. The treatment temperature was 35°C and the adsorption time of the modified molecular sieve was 2 hours.

[0037] S2: Dilute 45 kg of acrylic acid with water, the mass ratio of acrylic acid to water is 1:1, then use a 40% by mass sodium hydroxide aqueous solution to adjust the neutralization degree of acrylic acid to 60%, add 25 kg of sodium p-styrene sulfonate and 13 kg of polyvinyl alcohol, mix and stir evenly, add 0.1 kg of cross-linking agent, heat to 65°C, add 0.3 kg of initiator and react for 5 hours, take the product, dry and crush it to obtain a water-absorbing resin.

[0038] S3: The isopropyl alcohol treated by modified molecular sieve adsorption is then treated by a water-absorbent resin. The water-absorbent resin is purchased from a SAP water-absorbent resin with a particle size range of 30-80 meshes. The isopropyl alcohol dehydrated by the water-absorbent resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2.5 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution. The secondary isopropyl alcohol solution is distilled to obtain high-purity isopropyl alcohol with a purity of 99.99%.

[0039] Example 6 This embodiment provides a purification process for high-purity isopropanol, comprising the following specific steps: S1: Mix the crude isopropanol product with a phosphate buffer solution, wherein the phosphate buffer solution is an aqueous solution of sodium dihydrogen phosphate, the concentration of the phosphate buffer solution is 0.1 mol / L, and the pH of the phosphate buffer solution is 7.3, and then distill to obtain a preliminarily purified material.

[0040] S2: Mix Hβ molecular sieve with phosphoric acid aqueous solution. Hβ molecular sieve was purchased from the catalyst factory of Nankai University. The concentration of phosphoric acid aqueous solution was 1 mol / L. The mass ratio of Hβ molecular sieve to phosphoric acid aqueous solution was 1:4. Stir at room temperature for 1 hour, filter and wash, dry at 110°C, and calcine at 550°C for 3.5 hours to obtain a modified molecular sieve. The primary purified material was subjected to adsorption treatment with the modified molecular sieve. The treatment temperature was 35°C and the adsorption time of the modified molecular sieve was 2 hours.

[0041] S3: Dilute 45 kg of acrylic acid with water, the mass ratio of acrylic acid to water is 1:1, then use a 40% by mass sodium hydroxide aqueous solution to adjust the neutralization degree of acrylic acid to 60%, add 4 kg of sodium carboxymethyl cellulose, 25 kg of sodium p-styrene sulfonate, and 13 kg of polyvinyl alcohol, mix and stir evenly, add 0.1 kg of cross-linking agent, heat to 65°C, add 0.3 kg of initiator and react for 5 hours, take the product, dry and crush it to obtain a water-absorbing resin.

[0042] S4: The isopropyl alcohol treated by modified molecular sieve adsorption is then treated by a water-absorbent resin. The water-absorbent resin is purchased from a SAP water-absorbent resin with a particle size range of 30-80 meshes. The isopropyl alcohol dehydrated by the water-absorbent resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2.5 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution. The secondary isopropyl alcohol solution is distilled to obtain high-purity isopropyl alcohol with a purity of 99.99%.

[0043] Example 7 The difference between Example 7 and Example 6 is that in the purification process of high-purity isopropyl alcohol, the amount of initiator used is 0.1 kg, the amount of cross-linking agent used is 0.05 kg, the amount of acrylic acid used is 40 kg, the amount of sodium p-styrene sulfonate used is 20 kg, the amount of polyvinyl alcohol used is 15 kg, and the amount of sodium carboxymethyl cellulose used is 3 kg.

[0044] Example 8 The difference between Example 8 and Example 6 is that in the purification process of high-purity isopropyl alcohol, the amount of initiator used is 0.5 kg, the amount of cross-linking agent used is 0.15 kg, the amount of acrylic acid used is 50 kg, the amount of sodium p-styrene sulfonate used is 30 kg, the amount of polyvinyl alcohol used is 10 kg, and the amount of sodium carboxymethyl cellulose used is 5 kg.

[0045] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the purification process of high-purity isopropanol does not use a phosphate buffer solution.

[0046] A purification process for high-purity isopropanol comprises the following specific steps: S1: distilling the crude isopropanol to obtain a preliminary purified material, and subjecting the primary purified material to molecular sieve adsorption treatment at a temperature of 35°C and a molecular sieve adsorption time of 2 hours. The molecular sieve is Hβ molecular sieve, which is purchased from the catalyst factory of Nankai University. The isopropanol after the molecular sieve adsorption treatment is then treated with a water-absorbent resin, which is purchased from a SAP water-absorbent resin with a particle size range of 30-80 meshes.

[0047] S2: The isopropyl alcohol dehydrated by the water-absorbing resin is passed through a reverse osmosis membrane with a reverse osmosis pressure of 2.5 MPa, a permeation rate of 500 L / h, and a circulation rate of 800 L / h to obtain a secondary isopropyl alcohol solution. The secondary isopropyl alcohol solution is distilled to obtain high-purity isopropyl alcohol with a purity of 99.9%.

[0048] Performance testing The following performance tests were performed on the secondary isopropyl alcohol solution and the high-purity isopropyl alcohol product in the isopropyl alcohol purification process provided in Examples 1-8 of the present application and Comparative Example 1. The specific test results are shown in Table 1.

[0049] Detection Methods The water content in isopropanol was analyzed and detected by Karl Fischer moisture analyzer, the metal ion content in isopropanol was analyzed and detected by plasma mass spectrometer, and the anion content in isopropanol was analyzed and detected by liquid ion chromatography.

[0050] Table 1: Content detection data table It can be seen from the content detection of the isopropanol product and the secondary isopropanol solution that the present application pre-mixes the isopropanol crude product with a phosphate buffer solution, and then combines the molecular sieve adsorption, water-absorbing resin dehydration, and reverse osmosis membrane treatment process to obtain a secondary isopropanol solution with water content significantly reduced, remove the impurity content in the isopropanol, and improve the purity of the isopropanol. It can be seen from the comparison of Example 1 and Comparative Example 1 that Comparative Example 1 does not use a phosphate buffer solution, and it can be seen from the performance test results that the water content in the isopropanol product is significantly increased, although under the synergistic effect of other processes, isopropanol can maintain a good purity, but the water content is high and difficult to remove.

[0051] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A purification process for high-purity isopropanol, characterized in that: The specific steps include: The crude isopropanol product is mixed with a phosphate buffer solution and distilled to obtain a preliminary purified material, the primary purified material is sequentially subjected to molecular sieve adsorption and water-absorbing resin dehydration, the isopropanol dehydrated by the resin is passed through a reverse osmosis membrane to obtain a secondary isopropanol solution, the secondary isopropanol solution is distilled to obtain high-purity isopropanol; the pH of the phosphate buffer solution is 7-8.

2. The purification process of high-purity isopropyl alcohol according to claim 1, characterized in that: The concentration of the phosphate buffer solution is 0.05-0.15 mol / L.

3. The purification process of high-purity isopropanol according to claim 1, characterized in that: When the isopropanol passes through the reverse osmosis membrane, the reverse osmosis pressure is 2-2.8 MPa and the permeation rate is 400-600 L / h.

4. The purification process of high-purity isopropyl alcohol according to claim 1, characterized in that: The temperature during the molecular sieve adsorption treatment is 30-40° C., and the molecular sieve adsorption treatment time is 1.5-2.5 hours.

5. The purification process of high-purity isopropanol according to claim 4, characterized in that: The molecular sieve is modified by phosphoric acid, and the modification method comprises the following specific steps: adding the molecular sieve into a phosphoric acid aqueous solution, stirring for 1-2 hours, filtering and drying at 100-120° C., and then calcining at 500-600° C. for 3-4 hours to obtain a modified molecular sieve.

6. The purification process of high-purity isopropyl alcohol according to claim 1, characterized in that: The water-absorbing resin comprises the following raw materials in parts by weight: 0.1-0.5 parts of an initiator, 0.05-0.15 parts of a cross-linking agent, 40-50 parts of acrylic acid, 20-30 parts of sodium p-styrene sulfonate, and 10-15 parts of polyvinyl alcohol.

7. The purification process of high-purity isopropyl alcohol according to claim 6, characterized in that: The water-absorbing resin raw material also includes 3-5 parts of sodium carboxymethyl cellulose.

8. The process for purifying high-purity isopropyl alcohol according to claim 7, characterized in that: The preparation method of the water-absorbing resin comprises the following specific steps: Acrylic acid is diluted with water, and then sodium hydroxide is used to adjust the neutralization degree of acrylic acid, sodium carboxymethyl cellulose, sodium p-styrene sulfonate, and polyvinyl alcohol are added and mixed, and stirred evenly, a cross-linking agent is added, and the mixture is heated to 60-70° C., an initiator is added to react, and the product is dried and crushed to obtain a water-absorbing resin.

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