Preparation method of ultra-pure hydroxylamine aqueous solution

Abstract

The invention discloses a preparation method of an ultra-pure hydroxylamine aqueous solution, and relates to the field of organic chemistry and chemical industry production. The method comprises the following steps: reacting electronic-grade hydroxylamine salt with organic alkali in a proper solvent to generate hydroxylamine, then separating and removing salt and unreacted hydroxylamine in a reaction solution through a mercaptopyridine ion exchange modified membrane, and finally concentrating the solution into 50wt% ultra-high-purity hydroxylamine aqueous solution by adopting reduced pressure evaporation or multi-effect evaporation. The process has the characteristics of high efficiency, environmental protection, simplicity and easiness in operation, effectively improves the purity, yield and separation efficiency of hydroxylamine, and meets the strict requirements of electronic grade hydroxylamine on purity and metal ion content.

Description

Technical Field

[0001] This invention relates to the fields of organic chemistry and chemical production, and in particular to a method for preparing an ultra-high purity hydroxylamine aqueous solution. Background Technology

[0002] Hydroxylamine (NH₂OH) is an important chemical reagent widely used in semiconductor manufacturing, photolithography, chemical analysis, pesticide synthesis, and reduction reactions. Particularly in the semiconductor industry, hydroxylamine, as an electronic-grade chemical, is commonly used in critical processes such as photoresist development, cleaning, and metal layer removal. However, electronic-grade hydroxylamine has extremely stringent requirements regarding metal ions, generally needing to reach the ppb level to avoid adversely affecting the minute structures in semiconductor circuits. To meet this high purity requirement, effective production and purification technologies must be employed.

[0003] Currently, there are two main methods for producing electronic-grade hydroxylamine: one is the reduction method using ammonia as a raw material, and the other is the reduction method using hydroxylamine salts as raw materials. The former uses ammonia gas to react with a reducing agent (such as iron powder, zinc powder, etc.) to produce hydroxylamine. Although this method has high reduction efficiency, it suffers from problems such as numerous byproducts, demanding operating conditions, and difficulty in controlling product purity. The latter uses electronic-grade hydroxylamine salts (such as hydroxylamine chloride, hydroxylamine sulfate, etc.) as raw materials, synthesizing pure hydroxylamine through reaction with an organic base. This method is relatively simple to operate, and by adjusting the reaction conditions and subsequent processing, higher hydroxylamine purity can be achieved.

[0004] Currently, the process of synthesizing hydroxylamine by reacting organic bases with electronic-grade hydroxylamine salts has been applied to some extent, but existing production methods still face the following problems: Insufficient reaction purity: Although the hydroxylamine produced by the reaction of organic base with electronic grade hydroxylamine salt is relatively pure, a certain amount of salt and unreacted hydroxylamine may still be generated during the reaction, resulting in the final product's purity failing to meet the requirements of electronic grade.

[0005] Low impurity removal efficiency: Current conventional methods rely on precipitation, centrifugation or simple filtration to remove salts and impurities from reaction residues. However, these methods are often inefficient and cannot completely remove salts and other impurities from the reaction process, resulting in products containing high levels of metal ions and other contaminants, which cannot meet high purity requirements.

[0006] Concentration process is complex: Existing concentration processes mostly use evaporation to increase the concentration of hydroxylamine solution. However, due to the high volatility of hydroxylamine and the possibility of decomposition during evaporation, it is difficult to control process parameters, resulting in low hydroxylamine yield and potentially affecting the purity of the final product. Summary of the Invention

[0007] To address the shortcomings of existing production processes, this invention proposes a method for preparing ultra-high purity hydroxylamine aqueous solution. By rationally selecting reaction raw materials, solvents, and reaction conditions, the synthesis process of hydroxylamine is optimized. Furthermore, by combining membrane separation and concentration technologies, the salts generated during the reaction and unreacted hydroxylamine are successfully removed.

[0008] The technical solution is as follows: A method for preparing an ultra-high purity hydroxylamine aqueous solution includes the following steps: Step 1: Add 100-200 parts of electronic grade hydroxylamine salt and 200-500 parts of organic base to 150-300 parts of deionized water, react under the set reaction conditions, and after the reaction is completed, cool to room temperature to obtain hydroxylamine solution; Step 2: The reaction solution is separated using a mercaptopyridine ion exchange modified membrane via membrane separation technology. The operating pressure is 5-10 MPa and the operating temperature is 25-40℃ to remove salts and unreacted hydroxylamine from the reaction system, resulting in a purified aqueous solution of hydroxylamine. Step 3: The separated solution is concentrated by vacuum evaporation to a 50wt% ultra-high purity hydroxylamine aqueous solution.

[0009] In some embodiments of the present invention, the electronic-grade hydroxylamine salt is selected from hydroxylamine chloride, hydroxylamine sulfate, and mixtures thereof.

[0010] In some embodiments of the present invention, the organic base is selected from triethanolamine, diethylaminoethanol and mixtures thereof.

[0011] In some embodiments of the present invention, the reaction temperature is 0-50°C, the reaction time is 2-3 hours, and the stirring speed is 200-500 rpm.

[0012] In some embodiments of the present invention, the preparation method of the mercaptopyridine ion exchange modified membrane is as follows, according to mass fraction: Swelling: Immerse 100 parts of polystyrene film in 50-100 parts of dichloromethane and swell at room temperature for 30-60 minutes; Sulfonation reaction: Add 5-10 parts of chlorosulfonic acid, 1-2 parts of 4-amino-3-mercaptopyridine and 0.1-0.3 parts of aluminum chloride catalyst to dichloromethane, and add it dropwise to the swollen membrane at 0-10℃ for 1-3 hours. Neutralization and cleaning: The membrane after the reaction is neutralized with NaOH solution, and then rinsed with deionized water until neutral to obtain the mercaptopyridine ion exchange modified membrane.

[0013] In some embodiments of the present invention, the operating flow rate of the membrane separation technology is 0.5-1.5 L / h·m. 2 .

[0014] In some embodiments of the present invention, the temperature of the reduced pressure evaporation is 50-70°C and the operating pressure is 50-200 mmHg.

[0015] Compared with the prior art, the present invention has the following advantages: 1) High-purity product: Salt and impurities are effectively removed through membrane separation technology to ensure compliance with the requirements of electronic-grade hydroxylamine.

[0016] 2) High separation efficiency: By optimizing membrane separation operating conditions, impurities in the reaction solution can be removed efficiently, product purity can be improved, and adverse reactions can be reduced.

[0017] 3) Simple and efficient concentration process: Concentration methods such as vacuum evaporation or multi-effect evaporation not only effectively avoid the thermal decomposition of hydroxylamine, but also improve the concentration efficiency and ensure high yield and purity.

[0018] 4) High scalability: This method is applicable to large-scale industrial production, with low equipment investment, simple operation, and is suitable for large-scale production of electronic-grade hydroxylamine.

[0019] 5) The mercaptopyridine ion exchange modified membrane has the following beneficial effects: High selectivity: The mercaptopyridine group has a special affinity for hydroxylamine, and achieves highly efficient and selective separation of hydroxylamine through ion exchange and coordination, significantly improving the purity of the purified hydroxylamine.

[0020] Good hydrophilicity and antifouling properties: The sulfonic acid groups and mercaptopyridine groups introduced by sulfonation increase the hydrophilicity of the membrane surface, reduce the adsorption and deposition of impurities on the membrane surface, and improve the membrane's antifouling performance and service life.

[0021] High operational stability: The modified membrane has a stable chemical structure, can be used in a wide range of pH and temperature conditions, and maintains stable performance during long-term operation, reducing the frequency and cost of membrane replacement.

[0022] Simple process: The preparation process is relatively simple, the raw material cost is low, it is easy to industrialize and apply, and it has good economic and social benefits. Detailed Implementation

[0023] The features of the present invention are further illustrated below through embodiments, but the scope of protection of this patent is not limited to the embodiments.

[0024] Example 1 Raw material formula: Electronic grade hydroxylamine salt (hydroxylamine chloride): 100g Organic base (triethanolamine): 200g Solvent (deionized water): 150g Preparation steps: Step 1 (Reaction Preparation): Add 100g of hydroxylamine chloride and 120g of triethanolamine to 150g of ethanol and stir until well mixed.

[0025] Heat to 0°C, maintain stirring speed at 200 rpm, and react for 2 hours.

[0026] After the reaction was complete, the solution was naturally cooled to room temperature to obtain a hydroxylamine solution.

[0027] Step 2 (Membrane separation and purification): The above solution was separated using a mercaptopyridine ion-exchange modified membrane.

[0028] The operating pressure is controlled at 5 MPa, the operating temperature at 25℃, and the operating flow rate at 0.5 L / h·m. 2 .

[0029] Remove the salt and unreacted hydroxylamine from the system to obtain a purified aqueous solution of hydroxylamine.

[0030] Step 3 (Concentration under reduced pressure): The purified solution was fed into a vacuum evaporator, and the evaporation temperature was set to 50℃ and the operating pressure to 50mmHg.

[0031] The solution was concentrated to obtain an ultra-high purity hydroxylamine aqueous solution.

[0032] Preparation of mercaptopyridine ion exchange modified membrane: Swelling: 100g of polystyrene film was immersed in 50g of dichloromethane and swelled at room temperature for 30 minutes.

[0033] Sulfonation reaction: 5g chlorosulfonic acid, 1g 4-amino-3-mercaptopyridine and 0.1g aluminum chloride were added to dichloromethane and added dropwise to the swollen membrane at 0℃, and the reaction was carried out for 1h.

[0034] Neutralization and cleaning: Neutralize the membrane with NaOH solution to pH=7, rinse 3 times with deionized water, and air dry for later use.

[0035] Example 2 Raw material formula: Electronic grade hydroxylamine salt (hydroxylamine sulfate): 130g Organic base (diethylaminoethanol): 260g Solvent (deionized water): 200g Preparation steps: Step 1 (Reaction Preparation): Add 130g of hydroxylamine sulfate and 160g of diethylaminoethanol to 200g of methanol and stir until well mixed.

[0036] Heat to 20°C, maintain stirring speed at 300 rpm, and react for 2.3 hours.

[0037] After the reaction was complete, the solution was naturally cooled to room temperature to obtain a hydroxylamine solution.

[0038] Step 2 (Membrane separation and purification): The above solution was separated using a mercaptopyridine ion-exchange modified membrane.

[0039] The operating pressure is controlled at 6 MPa, the operating temperature at 30℃, and the operating flow rate at 0.8 L / h·m. 2 .

[0040] Remove the salt and unreacted hydroxylamine from the system to obtain a purified aqueous solution of hydroxylamine.

[0041] Step 3 (Concentration under reduced pressure): The purified solution was fed into a vacuum evaporator, and the evaporation temperature was set to 55℃ and the operating pressure to 100mmHg.

[0042] The solution was concentrated to obtain an ultra-high purity hydroxylamine aqueous solution.

[0043] Preparation of mercaptopyridine ion exchange modified membrane: Swelling: 100g of polystyrene film was immersed in 65g of dichloromethane and swelled at room temperature for 40 minutes.

[0044] Sulfonation reaction: 7g chlorosulfonic acid, 1.3g 4-amino-3-mercaptopyridine and 0.2g aluminum chloride were added to dichloromethane and added dropwise to the swollen membrane at 5°C for 2 hours.

[0045] Neutralization and cleaning: Neutralize the membrane with NaOH solution to pH=7, rinse 3 times with deionized water, and air dry for later use.

[0046] Example 3 Raw material formula: Electronic grade hydroxylamine salt (hydroxylamine chloride): 170g Organic base (diethylaminoethanol): 400g Solvent (deionized water): 250g Preparation steps: Step 1 (Reaction Preparation): Add 170g of mixed hydroxylamine salt and 200g of mixed organic base to 250g of deionized water and stir well.

[0047] Heat to 35°C, maintain stirring speed at 400 rpm, and react for 2.7 hours.

[0048] After the reaction was complete, the solution was naturally cooled to room temperature to obtain a hydroxylamine solution.

[0049] Step 2 (Membrane separation and purification): The above solution was separated using a mercaptopyridine ion-exchange modified membrane.

[0050] The operating pressure is controlled at 8 MPa, the operating temperature at 35℃, and the operating flow rate at 1.2 L / h·m. 2 .

[0051] Remove the salt and unreacted hydroxylamine from the system to obtain a purified aqueous solution of hydroxylamine.

[0052] Step 3 (Concentration under reduced pressure): The purified solution was fed into a vacuum evaporator, and the evaporation temperature was set to 60℃ and the operating pressure to 150mmHg.

[0053] The solution was concentrated to obtain an ultra-high purity hydroxylamine aqueous solution.

[0054] Preparation of mercaptopyridine ion exchange modified membrane: Swelling: 100g of polystyrene film was immersed in 80g of dichloromethane and swelled at room temperature for 45 minutes.

[0055] Sulfonation reaction: 8g chlorosulfonic acid, 1.5g 4-amino-3-mercaptopyridine and 0.2g aluminum chloride were added to dichloromethane and added dropwise to the swollen membrane at 5°C for 2 hours.

[0056] Neutralization and cleaning: Neutralize the membrane with NaOH solution to pH=7, rinse 3 times with deionized water, and air dry for later use.

[0057] Example 4 Raw material formula: Electronic grade hydroxylamine salt (hydroxylamine sulfate): 200g Organic base (triethanolamine): 500g Solvent (deionized water): 300g Preparation steps: Step 1 (Reaction Preparation): Add 200g of mixed hydroxylamine salt and 240g of mixed organic base to 300g of deionized water and stir well.

[0058] Heat to 45°C, maintain stirring speed at 500 rpm, and react for 3 hours.

[0059] After the reaction was complete, the solution was naturally cooled to room temperature to obtain a hydroxylamine solution.

[0060] Step 2 (Membrane separation and purification): The above solution was separated using a mercaptopyridine ion-exchange modified membrane.

[0061] Control the operating pressure at 10 MPa, the operating temperature at 40℃, and the operating flow rate at 1.5 L / h·m. 2 .

[0062] Remove the salt and unreacted hydroxylamine from the system to obtain a purified aqueous solution of hydroxylamine.

[0063] Step 3 (Concentration under reduced pressure): The purified solution was fed into a vacuum evaporator, and the evaporation temperature was set to 70℃ and the operating pressure to 200mmHg.

[0064] The solution was concentrated to obtain an ultra-high purity hydroxylamine aqueous solution.

[0065] Preparation of mercaptopyridine ion exchange modified membrane: Swelling: 100g of polystyrene film was immersed in 100g of dichloromethane and swelled at room temperature for 60 minutes.

[0066] Sulfonation reaction: 10g chlorosulfonic acid, 2g 4-amino-3-mercaptopyridine and 0.3g aluminum chloride were added to dichloromethane and added dropwise to the swollen membrane at 10°C for 3 hours.

[0067] Neutralization and cleaning: Neutralize the membrane with NaOH solution to pH=7, rinse 3 times with deionized water, and air dry for later use.

[0068] Comparative Example 1 Raw material formula: Electronic grade hydroxylamine salt (hydroxylamine chloride): 100g Organic base (triethanolamine): 200g Solvent (deionized water): 150g Preparation steps: Step 1 (Reaction Preparation): Add 100g of hydroxylamine chloride and 120g of triethanolamine to 150g of ethanol and stir until well mixed.

[0069] Heat to 0°C, maintain stirring speed at 200 rpm, and react for 2 hours.

[0070] After the reaction was complete, the solution was naturally cooled to room temperature to obtain a hydroxylamine solution.

[0071] Step 2 (Membrane separation and purification): The above solution was separated using a mercaptopyridine ion-exchange modified membrane.

[0072] The operating pressure is controlled at 5 MPa, the operating temperature at 25℃, and the operating flow rate at 0.5 L / h·m. 2 .

[0073] Remove the salt and unreacted hydroxylamine from the system to obtain a purified aqueous solution of hydroxylamine.

[0074] Step 3 (Concentration under reduced pressure): The purified solution was fed into a vacuum evaporator, and the evaporation temperature was set to 50℃ and the operating pressure to 50mmHg.

[0075] The solution was concentrated to obtain an ultra-high purity hydroxylamine aqueous solution.

[0076] Preparation of mercaptopyridine ion exchange modified membrane: Swelling: 100g of polystyrene film was immersed in 50g of dichloromethane and swelled at room temperature for 30 minutes.

[0077] Sulfonation reaction: Add 5g chlorosulfonic acid and 0.1g aluminum chloride to dichloromethane, and add dropwise to the swollen membrane at 0℃, and react for 1h.

[0078] Neutralization and cleaning: Neutralize the membrane with NaOH solution to pH=7, rinse 3 times with deionized water, and air dry for later use.

[0079] Comparative Example 2 Raw material formula: Electronic grade hydroxylamine salt (hydroxylamine chloride): 100g Organic base (triethanolamine): 200g Solvent (deionized water): 150g Preparation steps: Step 1 (Reaction Preparation): Add 100g of hydroxylamine chloride and 120g of triethanolamine to 150g of ethanol and stir until well mixed.

[0080] Heat to 0°C, maintain stirring speed at 200 rpm, and react for 2 hours.

[0081] After the reaction was complete, the solution was naturally cooled to room temperature to obtain a hydroxylamine solution.

[0082] Step 2 (Membrane separation and purification): The above solution was separated using a mercaptopyridine ion-exchange modified membrane.

[0083] The operating pressure is controlled at 5 MPa, the operating temperature at 25℃, and the operating flow rate at 0.5 L / h·m. 2 .

[0084] Remove the salt and unreacted hydroxylamine from the system to obtain a purified aqueous solution of hydroxylamine.

[0085] Step 3 (Concentration under reduced pressure): The purified solution was fed into a vacuum evaporator, and the evaporation temperature was set to 50℃ and the operating pressure to 50mmHg.

[0086] The solution was concentrated to obtain an ultra-high purity hydroxylamine aqueous solution.

[0087] Preparation of mercaptopyridine ion exchange modified membrane: Swelling: 100g of polystyrene film was immersed in 50g of dichloromethane and swelled at room temperature for 30 minutes.

[0088] Sulfonation reaction: 1g of 4-amino-3-mercaptopyridine and 0.1g of aluminum chloride were added to dichloromethane and added dropwise to the swollen membrane at 0°C for 1 hour.

[0089] Neutralization and cleaning: Neutralize the membrane with NaOH solution to pH=7, rinse 3 times with deionized water, and air dry for later use.

[0090] Test method: 1) Hydroxylamine purity test: Test method: The purity of hydroxylamine solution was tested by high performance liquid chromatography (HPLC). The sample was passed through a C18 reversed-phase column using methanol and water as the mobile phase, the column temperature was maintained at 30℃, and a UV detector was used with a detection wavelength of 210 nm.

[0091] 2) Metal ion content detection: Test method: The metal ion content in the samples was detected using inductively coupled plasma mass spectrometry (ICPMS). The test equipment was a PerkinElmer ICP-MS instrument, and standard elemental analysis procedures were used.

[0092] 3) Yield testing: Test method: The yield of hydroxylamine is calculated based on the mass of the starting materials and the final product. The final yield is calculated by measuring the change in solution concentration before and after the reaction by weighing or volume measurement, combined with the amount of product obtained after final concentration.

[0093] Test results: % purity of hydroxylamine aqueous solution Metal impurity content (ppb) Yield % Example 1 50.8 1 87.7 Example 2 51.2 0.9 88.1 Example 3 51.5 0.8 88.4 Example 4 51.7 0.6 88.6 Comparative Example 1 50.0 1.5 87.4 Comparative Example 2 49.8 1.3 87.2 Therefore, the method provided by this invention can effectively improve the purity, yield and production efficiency of electronic-grade hydroxylamine, while reducing energy consumption and environmental pollution during the production process. It is an innovative process with broad application prospects.

[0094] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure made using the content of the present invention specification, or any direct or indirect application in other related technical fields, shall also be included within the patent protection scope of the present invention.

Claims

1. A method for preparing an ultra-high purity aqueous hydroxylamine solution, characterized by, The method comprises the following steps, in terms of mass fraction: Step 1: 100-200 parts of electronic grade hydroxylamine salt and 200-500 parts of organic base are added to 150-300 parts of deionized water, and reacted under the set reaction conditions; after the reaction is completed, it is cooled to room temperature to obtain a hydroxylamine solution; Step 2: The reaction solution is separated by a membrane separation technology, and a sulfhydryl pyridine ion exchange modified membrane is used to remove salt and unreacted hydroxylamine in the reaction system, so as to obtain a purified hydroxylamine aqueous solution; the operating pressure is 5-10 MPa, and the operating temperature is 25-40℃; Step 3: The separated solution is concentrated by vacuum evaporation to obtain a 50wt% ultra-high purity hydroxylamine aqueous solution; The sulfhydryl pyridine ion exchange modified membrane is prepared by neutralization and washing after reaction of polystyrene membrane, chlorosulfonic acid, 4-amino-3-mercaptopyridine and aluminum chloride catalyst.

2. The method for preparing an ultra-high purity hydroxylamine aqueous solution according to claim 1, characterized in that: The electronic grade hydroxylamine salt is selected from hydroxylamine chloride, hydroxylamine sulfate and mixtures thereof.

3. The method for preparing an ultra-high purity hydroxylamine aqueous solution according to claim 1, characterized in that: The organic base is selected from triethanolamine, diethylaminoethanol and mixtures thereof.

4. The method for preparing an ultra-high purity hydroxylamine aqueous solution according to claim 1, characterized in that: The reaction temperature of step 1 is 0-50℃, the reaction time is 2-3 hours, and the stirring speed is 200-500 rpm.

5. The method of claim 1, wherein the method is characterized by: The preparation method of the sulfhydryl pyridine ion exchange modified membrane is as follows, in terms of mass fraction: Swelling: 100 parts of polystyrene membrane are immersed in 50-100 parts of dichloromethane, and swelled at room temperature for 30-60 min; Sulfonation reaction: 5-10 parts of chlorosulfonic acid, 1-2 parts of 4-amino-3-mercaptopyridine and 0.1-0.3 parts of aluminum chloride catalyst are added to dichloromethane, and then added dropwise into the swelled membrane at 0-10℃, and reacted for 1-3h; Neutralization and washing: the reacted membrane is neutralized with NaOH solution, and then washed with deionized water until neutral to obtain the sulfhydryl pyridine ion exchange modified membrane.

6. The method of claim 1, wherein the method is characterized by: The operating flow rate of the membrane separation technique is 0.5-1.5 L / h·m 2 .

7. The method of claim 1, wherein the method is characterized by: The temperature of the vacuum evaporation is 50-70℃, and the operating pressure is 50-200mmHg.