A purification method for AMPS

Abstract

This invention provides a method for purifying AMPS, belonging to the field of sulfonic acid technology. The purification method includes dissolution and filtration, ion exchange purification, and crystallization. The dissolution and filtration method involves adding crude AMPS to methanol, stirring and dissolving at 30–50°C, then adding trisodium citrate, stirring until homogeneous, allowing it to stand for 20–30 minutes, and then filtering through a 0.2–0.5 μm microporous membrane to obtain the filtrate. The purified AMPS of this invention has a purity of 99.58–99.64%, wherein Fe... 3+ The mass content is ≤0.0003%, the yield is 86.21-86.35%, and the production rate is 92.46-92.51%.

Description

Technical Field

[0001] This invention belongs to the field of sulfonic acid technology, specifically relating to a method for purifying AMPS. Background Technology

[0002] 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) is an important functional monomer widely used in water treatment, oilfield chemistry, polymer materials and other fields. In the preparation of AMPS, whether through mainstream processes such as sulfonation or other synthetic methods, the crude AMPS often contains unreacted raw materials, impurities generated by side reactions, catalyst residues, polymerization inhibitors and so on. The presence of these impurities will affect the performance and application effect of AMPS. For example, in the polymerization reaction, impurities may cause the polymerization rate to be unstable, the polymer molecular weight distribution to be broadened and the product quality to be reduced.

[0003] Currently, common AMPS purification methods include recrystallization and ion exchange. While recrystallization is relatively simple to operate, its removal effect on certain impurities is limited, and repeated recrystallization leads to a decrease in product yield. Ion exchange can effectively remove ionic impurities, but the equipment cost is high, and the ion exchange resin requires regular regeneration and maintenance, increasing production costs and operational complexity. Therefore, there is an urgent need to develop an AMPS purification method that is simple to operate, has good purification effect, and is low in cost. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for purifying AMPS, achieving the following objectives: effectively removing various impurities from crude AMPS, significantly improving product purity, ensuring a high product yield, reducing production costs, and meeting the needs of industrial production.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for purifying AMPS, comprising:

[0007] 1. Dissolving and filtering

[0008] Crude AMPS was added to methanol and stirred at 30–50°C to dissolve. Then, trisodium citrate was added and stirred until homogeneous. After standing for 20–30 minutes, the solution was filtered through a 0.2–0.5 μm microporous membrane to obtain the filtrate.

[0009] The purity of the crude AMPS is 90-95%, of which Fe 3+ The mass content is 0.004% to 0.008%;

[0010] The mass ratio of crude AMPS, methanol, and trisodium citrate is 0.8–1.2:4.5–5.5:0.005–0.007.

[0011] The stirring speed is 25-35 r / min.

[0012] 2. Ion exchange purification

[0013] Soak the anion exchange resin in saturated saline solution for 18–22 h, wash with deionized water until the supernatant is colorless and odorless, then soak in NaOH solution for 3–5 h, wash with deionized water until neutral, and then soak in Na2SO4 solution for 1–3 h. Slowly transfer the resin into the chromatography column, and slowly load the filtrate from the top of the column at a flow rate of 2–4 BV / h. After loading, first elute with 15–25% methanol solution to remove weakly adsorbed impurities, then elute with 75–85% methanol solution, collect the liquid at the bottom of the column to obtain the AMPS solution.

[0014] The concentration of the NaOH solution is 0.8–1.2 mol / L;

[0015] The concentration of the Na2SO4 solution is 0.45–0.55 mol / L;

[0016] The anion exchange resin is prepared by mixing styrene, divinylbenzene, and benzoyl peroxide, stirring until homogeneous, and slowly adding the mixture dropwise to a polyvinyl alcohol solution at 60–70°C. The temperature is then raised to 80–90°C, and the reaction is carried out for 4–6 hours. After cooling at room temperature, the mixture is filtered, washed with hot water, and white sphere resin is obtained. The white sphere resin is then soaked in dichloroethane and swollen at room temperature for 4–6 hours. Anhydrous zinc chloride is then added, and the mixture is stirred at 40–50°C for 8–12 hours. After filtration, the resin is washed with methanol and deionized water until neutral to obtain chloromethylated resin. The chloromethylated resin is then added to a trimethylamine solution and stirred at room temperature for 10–12 hours. After filtration, the resin is washed with deionized water until neutral to obtain the anion exchange resin.

[0017] In the preparation method of the anion exchange resin, the mass ratio of styrene, divinylbenzene, benzoyl peroxide, and polyvinyl alcohol solution is 8.8–9.2:0.9–1.1:0.08–0.12:20–30;

[0018] The polyvinyl alcohol solution has a mass fraction of 0.4% to 0.6%.

[0019] The mass ratio of the white sphere resin, dichloroethane, and anhydrous zinc chloride is 0.8–1.2:6–8:0.7–0.9.

[0020] The mass ratio of the chloromethylated resin to the trimethylamine solution is 0.8–1.2:9–11;

[0021] The trimethylamine solution has a mass fraction of 30-40%.

[0022] 3. Crystallization

[0023] Acetone was added to the AMPS solution, and the crystals were cooled and crystallized at 0–5°C for 1–3 hours. The crystals were then dried under vacuum at 40–60°C to constant weight to obtain purified AMPS.

[0024] The mass ratio of the AMPS solution to acetone is 4–6:1.8–2.2.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] Adding trisodium citrate in step 1 can effectively complex metal ions in the solution, thereby removing them by filtration.

[0027] In step 2, the anion exchange resin utilizes the electrostatic interaction between the sulfonic acid groups (-SO3H) of AMPS and the quaternary ammonium groups (-N(CH3)3) on the resin to effectively and accurately adsorb AMPS. Through elution, a high-purity AMPS solution is obtained.

[0028] In step 3, acetone was added during the crystallization process. Acetone is miscible with methanol in the AMPS solution, but almost insoluble with AMPS. Adding acetone to the AMPS solution can make AMPS crystallize quickly, thereby separating impurities and avoiding multiple crystallizations to obtain purified AMPS.

[0029] The purified AMPS obtained in this invention has a purity of 99.58%–99.64%, of which Fe... 3+ The mass content is ≤0.0003%, the yield is 86.21-86.35%, and the production rate is 92.46-92.51%. Detailed Implementation

[0030] Example 1

[0031] A method for purifying AMPS, comprising:

[0032] 1. Dissolving and filtering

[0033] Crude AMPS was added to methanol and stirred at 40°C to dissolve. Then, trisodium citrate was added, stirred evenly, and allowed to stand for 25 minutes. The solution was then filtered through a 0.3 μm microporous membrane to obtain the filtrate.

[0034] The purity of the crude AMPS is 95%, of which Fe 3+ The mass content is 0.006%;

[0035] The mass ratio of crude AMPS, methanol, and trisodium citrate is 1:5:0.006.

[0036] The stirring rate was 30 r / min.

[0037] 2. Ion exchange purification

[0038] Soak the anion exchange resin in saturated saline for 20 hours, wash with deionized water until the supernatant is colorless and odorless, then soak in NaOH solution for 4 hours, wash with deionized water until neutral, and then soak in Na2SO4 solution for 2 hours. Slowly transfer the resin into the chromatography column, and slowly load the filtrate from the top of the column at a flow rate of 3 BV / h. After loading, first elute with 20% methanol solution to remove weakly adsorbed impurities, then elute with 80% methanol solution, collect the liquid at the bottom of the column to obtain the AMPS solution.

[0039] The concentration of the NaOH solution is 1 mol / L;

[0040] The concentration of the Na2SO4 solution is 0.5 mol / L;

[0041] The anion exchange resin is prepared by mixing styrene, divinylbenzene, and benzoyl peroxide, stirring until homogeneous, and slowly adding the mixture dropwise to a polyvinyl alcohol solution at 65°C. The mixture is then heated to 85°C and reacted for 5 hours. After cooling at room temperature, the mixture is filtered and washed with hot water to obtain white sphere resin. The white sphere resin is then soaked in dichloroethane and swollen at room temperature for 5 hours. Anhydrous zinc chloride is then added, and the mixture is stirred and reacted at 45°C for 10 hours. After filtration, the resin is washed with methanol and deionized water until neutral to obtain chloromethylated resin. The chloromethylated resin is then added to a trimethylamine solution and stirred and reacted at room temperature for 11 hours. After filtration, the resin is washed with deionized water until neutral to obtain the anion exchange resin.

[0042] In the preparation method of the anion exchange resin, the mass ratio of styrene, divinylbenzene, benzoyl peroxide, and polyvinyl alcohol solution is 9:1:0.1:25.

[0043] The polyvinyl alcohol solution has a mass fraction of 0.5%.

[0044] The mass ratio of the white sphere resin, dichloroethane, and anhydrous zinc chloride is 1:7:0.8;

[0045] The mass ratio of the chloromethylated resin to the trimethylamine solution is 1:10;

[0046] The trimethylamine solution has a mass fraction of 35%.

[0047] 3. Crystallization

[0048] Acetone was added to the AMPS solution, and the crystals were cooled and crystallized at 3°C ​​for 2 hours. The crystals were then dried under vacuum at 50°C to constant weight to obtain purified AMPS.

[0049] The mass ratio of the AMPS solution to acetone is 5:2.

[0050] Example 2

[0051] A method for purifying AMPS, comprising:

[0052] 1. Dissolving and filtering

[0053] Crude AMPS was added to methanol and stirred at 30°C to dissolve. Then, trisodium citrate was added, stirred evenly, and allowed to stand for 20 minutes. The solution was then filtered through a 0.2 μm microporous membrane to obtain the filtrate.

[0054] The purity of the crude AMPS is 95%, of which Fe 3+ The mass content is 0.006%;

[0055] The mass ratio of crude AMPS, methanol, and trisodium citrate is 0.8:4.5:0.005.

[0056] The stirring rate was 25 r / min.

[0057] 2. Ion exchange purification

[0058] Soak the anion exchange resin in saturated saline for 18 hours, wash with deionized water until the supernatant is colorless and odorless, then soak in NaOH solution for 3 hours, wash with deionized water until neutral, and then soak in Na2SO4 solution for 1 hour. Slowly transfer the resin into the chromatography column, and slowly load the filtrate from the top of the column at a flow rate of 2 BV / h. After loading, first elute with 15% methanol solution to remove weakly adsorbed impurities, then elute with 75% methanol solution, collect the liquid at the bottom of the column to obtain the AMPS solution.

[0059] The concentration of the NaOH solution is 0.8 mol / L;

[0060] The concentration of the Na2SO4 solution is 0.45 mol / L;

[0061] The anion exchange resin is prepared by mixing styrene, divinylbenzene, and benzoyl peroxide, stirring until homogeneous, and slowly adding the mixture dropwise to a polyvinyl alcohol solution at 60°C. The temperature is then raised to 80°C, and the reaction is carried out for 4 hours. After cooling at room temperature, the mixture is filtered, washed with hot water, and white sphere resin is obtained. The white sphere resin is then soaked in dichloroethane and swollen at room temperature for 4 hours. Anhydrous zinc chloride is then added, and the mixture is stirred at 40°C for 8 hours. After filtration, the resin is washed with methanol and deionized water until neutral to obtain chloromethylated resin. The chloromethylated resin is then added to a trimethylamine solution and stirred at room temperature for 10 hours. After filtration, the resin is washed with deionized water until neutral to obtain the anion exchange resin.

[0062] In the preparation method of the anion exchange resin, the mass ratio of styrene, divinylbenzene, benzoyl peroxide, and polyvinyl alcohol solution is 8.8:0.9:0.08:20.

[0063] The polyvinyl alcohol solution has a mass fraction of 0.4%.

[0064] The mass ratio of the white sphere resin, dichloroethane, and anhydrous zinc chloride is 0.8:6:0.7.

[0065] The mass ratio of the chloromethylated resin to the trimethylamine solution is 0.8:9;

[0066] The trimethylamine solution has a mass fraction of 30%.

[0067] 3. Crystallization

[0068] Acetone was added to the AMPS solution, and the crystals were cooled and crystallized at 0°C for 1 hour. The crystals were then vacuum dried at 40°C to constant weight to obtain purified AMPS.

[0069] The mass ratio of the AMPS solution to acetone is 4:1.8.

[0070] Example 3

[0071] A method for purifying AMPS, comprising:

[0072] 1. Dissolving and filtering

[0073] Crude AMPS was added to methanol and stirred at 50°C to dissolve. Then, trisodium citrate was added, stirred evenly, and allowed to stand for 30 minutes. The solution was then filtered through a 0.5 μm microporous membrane to obtain the filtrate.

[0074] The purity of the crude AMPS is 95%, of which Fe 3+ The mass content is 0.006%;

[0075] The mass ratio of crude AMPS, methanol, and trisodium citrate is 1.2:5.5:0.007.

[0076] The stirring rate was 35 r / min.

[0077] 2. Ion exchange purification

[0078] Soak the anion exchange resin in saturated saline for 22 hours, wash with deionized water until the supernatant is colorless and odorless, then soak in NaOH solution for 5 hours, wash with deionized water until neutral, and then soak in Na2SO4 solution for 3 hours. Slowly transfer the resin into the chromatography column, and slowly load the filtrate from the top of the column at a flow rate of 4 BV / h. After loading, first elute with 25% methanol solution to remove weakly adsorbed impurities, then elute with 85% methanol solution, collect the liquid at the bottom of the column to obtain the AMPS solution.

[0079] The concentration of the NaOH solution is 1.2 mol / L;

[0080] The concentration of the Na2SO4 solution is 0.55 mol / L;

[0081] The anion exchange resin is prepared by mixing styrene, divinylbenzene, and benzoyl peroxide, stirring until homogeneous, and slowly adding the mixture dropwise to a polyvinyl alcohol solution at 70°C. The mixture is then heated to 90°C and reacted for 6 hours. After cooling at room temperature, the mixture is filtered, washed with hot water, and white sphere resin is obtained. The white sphere resin is then soaked in dichloroethane and swollen at room temperature for 6 hours. Anhydrous zinc chloride is then added, and the mixture is stirred at 50°C for 12 hours. After filtration, the resin is washed with methanol and deionized water until neutral to obtain chloromethylated resin. The chloromethylated resin is then added to a trimethylamine solution and stirred at room temperature for 12 hours. After filtration, the resin is washed with deionized water until neutral to obtain the anion exchange resin.

[0082] In the preparation method of the anion exchange resin, the mass ratio of styrene, divinylbenzene, benzoyl peroxide, and polyvinyl alcohol solution is 9.2:1.1:0.12:30.

[0083] The polyvinyl alcohol solution has a mass fraction of 0.6%.

[0084] The mass ratio of the white sphere resin, dichloroethane, and anhydrous zinc chloride is 1.2:8:0.9;

[0085] The mass ratio of the chloromethylated resin to the trimethylamine solution is 1.2:11;

[0086] The trimethylamine solution has a mass fraction of 40%.

[0087] 3. Crystallization

[0088] Acetone was added to the AMPS solution, and the crystals were cooled and crystallized at 5°C for 3 hours. The crystals were then dried under vacuum at 60°C to constant weight to obtain purified AMPS.

[0089] The mass ratio of the AMPS solution to acetone is 6:2.2.

[0090] Example 4

[0091] A method for purifying AMPS, based on Example 1, except that step 2 is omitted, while the remaining steps are the same.

[0092] Example 5

[0093] A method for purifying AMPS, based on Example 1, omits the addition of trisodium citrate in step 1, while the remaining steps are the same.

[0094] Test example

[0095] 1. The AMPS obtained in Examples 1-5 were subjected to purity and Fe content tests, respectively. 3+ The mass content, yield, and production rate were tested, and the test results are shown in Table 1.

[0096] Yield = (Mass of purified AMPS / Mass of crude AMPS) × 100%

[0097] Yield = Actual output / Theoretical output × 100%

[0098] Table 1

[0099]

[0100] As can be seen from the above results, although the yield and production rate of Example 4 are slightly higher than those of Example 1, Example 4 lacks an anion exchange membrane, which makes it impossible to effectively remove ionic impurities, resulting in a decrease in purity. If it is necessary to improve the purity, multiple crystallizations are required, but this will lead to a decrease in yield and production rate.

[0101] Example 5 omitted the addition of trisodium citrate in step 1, resulting in ineffective removal of metal ions from the crude product, and the Fe content in the product was high. 3+ The mass content is >0.0003%.

Claims

1. A method for purifying AMPS, characterized in that: The purification method includes dissolution and filtration, ion exchange purification, and crystallization; The dissolution and filtration method is as follows: crude AMPS is added to methanol and stirred to dissolve at 30-50°C. Then, trisodium citrate is added, stirred evenly, and allowed to stand for 20-30 minutes. The solution is then filtered through a 0.2-0.5 μm microporous membrane to obtain the filtrate. The ion exchange purification method is as follows: soak the anion exchange resin in saturated saline for 18-22 hours, wash with deionized water until the supernatant is colorless and odorless, then soak in NaOH solution for 3-5 hours, wash with deionized water until neutral, and then soak in Na2SO4 solution for 1-3 hours. After that, slowly transfer the resin into the chromatography column, slowly load the filtrate from the top of the column, and control the flow rate at 2-4 BV / h. After loading, first elute with 15-25% methanol solution to remove weakly adsorbed impurities, then elute with 75-85% methanol solution, collect the liquid at the bottom of the column, and obtain the AMPS solution. The anion exchange resin is prepared by mixing styrene, divinylbenzene, and benzoyl peroxide, stirring until homogeneous, and slowly adding the mixture dropwise to a polyvinyl alcohol solution at 60–70°C. The temperature is then raised to 80–90°C, and the reaction is carried out for 4–6 hours. After cooling at room temperature, the mixture is filtered, washed with hot water, and white sphere resin is obtained. The white sphere resin is then soaked in dichloroethane and swollen at room temperature for 4–6 hours. Anhydrous zinc chloride is then added, and the mixture is stirred at 40–50°C for 8–12 hours. After filtration, the resin is washed with methanol and deionized water until neutral to obtain chloromethylated resin. The chloromethylated resin is then added to a trimethylamine solution and stirred at room temperature for 10–12 hours. After filtration, the resin is washed with deionized water until neutral to obtain the anion exchange resin.

2. The method for purifying AMPS according to claim 1, characterized in that: In the aforementioned dissolution and filtration method, the purity of the crude AMPS is 90-95%, of which Fe... 3+ The mass content was 0.004-0.008%, and the mass ratio of crude AMPS, methanol, and trisodium citrate was 0.8-1.2:4.5-5.5:0.005-0.007; the stirring speed was 25-35 r / min.

3. The method for purifying AMPS according to claim 1, characterized in that: In the ion exchange purification method, the concentration of NaOH solution is 0.8–1.2 mol / L; the concentration of Na2SO4 solution is 0.45–0.55 mol / L.

4. The method for purifying AMPS according to claim 1, characterized in that: In the preparation method of the anion exchange resin, the mass ratio of styrene, divinylbenzene, benzoyl peroxide, and polyvinyl alcohol solution is 8.8–9.2:0.9–1.1:0.08–0.12:20–30; the mass fraction of polyvinyl alcohol solution is 0.4–0.6%; the mass ratio of white sphere resin, dichloroethane, and anhydrous zinc chloride is 0.8–1.2:6–8:0.7–0.9; the mass ratio of chloromethylated resin and trimethylamine solution is 0.8–1.2:9–11; and the mass fraction of trimethylamine solution is 30–40%.

5. The method for purifying AMPS according to claim 1, characterized in that: The crystallization method is as follows: acetone is added to the AMPS solution, and the crystals are cooled and crystallized at 0-5°C for 1-3 hours. The crystals are then vacuum dried at 40-60°C to constant weight to obtain purified AMPS.

6. The method for purifying AMPS according to claim 5, characterized in that: In the crystallization method, the mass ratio of AMPS solution to acetone is 4-6:1.8-2.2.

Images