Manufacturing process for ultra-high purity acetic acid

Abstract

We provide a manufacturing process for ultra-high purity acetic acid. [Solution] The product is produced through a crude distillation, adsorption, fine distillation, and filtration process flow. In particular, modified cellulose and nitrogen / sulfur / molybdenum-doped carbon adsorbents are used in the adsorption process to efficiently remove organic impurities such as 2-butenal, 2-ethyl-2-butenal, and acetaldehyde.

Description

Technical Field

[0001] The present invention belongs to the technical field of the production of electronic-grade chemicals, and specifically relates to the production process of ultra-high purity acetic acid.

Background Art

[0002] Electronic-grade acetic acid is a kind of wet electronic chemical used in the microelectronics industry. It can effectively remove impurity particles, inorganic residues and carbon deposits on the wafer by washing the silicon wafer, etc., and is widely applied to the production of electronic components such as solar cells for solar power generation, flat panel displays, integrated circuits, etc.

[0003] In the production, transportation and storage processes of acetic acid, due to raw materials and equipment, some metal ions, dust particles, unreacted raw materials and intermediate products will inevitably be mixed into the product. However, these impurities are likely to cause delamination and lead to leakage current and dielectric breakdown of the P-N junction, etc. For integrated circuits with smaller line widths, extremely small amounts of metal ions and fine particles not only have the risk of damaging the entire circuit, but also organic substances in the solvent, such as aldehydes (with very strong reducibility), etc. will also have an adverse impact on the performance of the circuit. Therefore, with the rapid development of integrated circuits, the requirements for the purity of electronic-grade reagents are increasing. How to effectively remove metal ions, dust particles and organic impurities has become an urgent technical problem to be solved. Regarding acetic acid, since its impurities, such as 2-butenal and 2-ethyl-2-butenal, are likely to form an azeotrope with water, how to efficiently remove moisture and organic impurities has also become an urgent problem to be overcome.

[0004] CN114989005A discloses a method for producing electronic-grade acetic acid, comprising: step 1, removing some of the metal ions in initial industrial acetic acid with an ion exchange resin; step 2, further precision distilling the acetic acid obtained in step 1; and step 3, purifying and filtering the acetic acid after precision distillation again with an ion exchange resin to obtain the electronic-grade acetic acid. Although the process is simple, the effect of removing water and metal ions does not satisfy the requirements for high-purity acetic acid, and there is no mention of removing organic impurities that tend to azeotrope.

[0005] DE602007056379T2 discloses a method for purifying acetic acid, in which an acetic acid product stream and a hydroxyl compound selected from 2-methyl-1,3-propanediol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, cyclohexane-1,4-dimethanol, and mixtures thereof are introduced into a distillation column, aldehyde impurities react with the hydroxyl compound to form an acetal, water is removed from the top of the distillation column, and a substantially anhydrous acetic acid product stream containing acetic acid and the acetal is obtained from the distillation column. The patent provides a novel method for removing aldehydes, but the removal efficiency is relatively low.

[0006] The currently disclosed manufacturing process has relatively low efficiency in removing impurities such as metals, particles, organic impurities, and moisture, and cannot meet the needs for the production and mass production of high-grade electronic acetic acid. [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention provides a process for producing ultra-high purity acetic acid and aims to provide a novel and efficient method for improving the quality of acetic acid by reducing the content of impurities such as metals, particles, and water in electronic-grade acetic acid. [Means for solving the problem]

[0008] The object of the present invention is to overcome the shortcomings of the prior art and provide a process for producing ultra-high purity acetic acid. To achieve the above technical object, the technical solutions employed by the present invention are as follows: A process for producing ultra-high purity acetic acid, Crude distillation: Using industrial acetic acid as a raw material, crude distillation is performed to control the water content to 3% or less (1), Adsorption: Step (2) involves controlling the temperature of the acetic acid after crude distillation to 40-50°C and adsorbing and filtering it with modified cellulose and nitrogen / sulfur / molybdenum-doped carbon adsorbent. Precision distillation: Step (3) involves precision distillation of the adsorbed acetic acid to collect the fraction, The process includes (4) cooling the fraction and then filtering it to obtain ultra-high purity acetic acid, The step of producing modified cellulose includes modifying carboxylated cellulose with tetraethylenepentamine to obtain modified cellulose. The manufacturing step of the nitrogen-sulfur-molybdenum-doped carbon adsorbent involves preparing a dispersion using a nitrogen source, a molybdenum source, a sulfur source, and activated carbon, and then carrying out a hydrothermal reaction in a sealed environment.

[0009] Preferably, the mixing ratio of modified cellulose to nitrogen / sulfur / molybdenum-doped carbon adsorbent is 1:4 to 4:1.

[0010] More preferably, filtration is performed using an electronic-grade filter.

[0011] Preferably, the hydrothermal reaction temperature is 190-210°C.

[0012] Preferably, the molybdenum source is at least one of ammonium paramolybdate and ammonium molybdate.

[0013] Preferably, the sulfur source is at least one of thiourea, thioacetamide, and ammonium sulfide.

[0014] Preferably, the hydrothermal reaction temperature is 200°C.

[0015] Preferably, the nitrogen source is at least one of urea and triethylamine.

[0016] Preferably, the activated carbon is activated carbon that has undergone activation treatment.

[0017] Preferably, the average length of the cellulose is 800 nm or less.

[0018] Preferably, the average aspect ratio of the cellulose is 300 or less.

[0019] The selectable precision distillation conditions are: 45 or more trays, top pressure of 0.21-0.3 MPa, top temperature of 120-128°C, boiler pressure of 0.29-0.36 MPa, boiler temperature of 142-147°C, and reflux ratio of 4-10.

[0020] Preferably, the activation treatment of activated carbon involves immersing it in hydrogen peroxide solution for 2 to 6 hours, followed by filtration and drying. After activation and modification, the number of oxygen-containing functional groups such as hydroxyl groups, carboxyl groups, and ester groups on the surface of the activated carbon increases significantly.

[0021] Preferably, the activated carbon is added to a mixed solution containing a molybdenum source, a sulfur source, and a nitrogen source, stirred for 12-24 hours, the mixture is transferred to a polytetrafluoroethylene-lined stainless steel autoclave, heated at 190-210°C for 12-24 hours, and allowed to cool naturally to room temperature. After filtration, it is washed at least three times alternately with deionized water and ethanol, and then dried.

[0022] Preferably, the step of grafting tetraethylenepentamine onto carboxylated cellulose is as follows. Disperse carboxylated cellulose in deionized water, add N-hydroxysuccinimide and EDC, stir at room temperature, then add primary amine, adjust the pH to 3 - 6, react at 50 - 70 °C for 6 - 12 h, then add tetraethylenepentamine, and react at room temperature for 24 - 48 h while maintaining the pH at 3 - 6. After separation and drying, modified carboxylated cellulose is obtained. Preferably, the primary amine is n-hexylamine or n-nonylamine.

[0023] In the present invention, adsorption is carried out using a modified adsorbent after rough distillation. The adsorbent has good adsorption properties for organic impurities in acetic acid, such as acetaldehyde, 2-butenal, 2-ethyl-2-butenal, etc. In particular, by adsorbing 2-butenal and 2-ethyl-2-butenal, the problem that some organic impurities cannot be effectively removed when using precision distillation can be solved.

[0024] In another aspect of the present invention, the use of the modified carboxylated cellulose produced by the above method and a nitrogen-sulfur-molybdenum-doped carbon adsorbent in the removal of 2-butenal and 2-ethyl-2-butenal in an acetic acid solvent is provided.

Advantages of the Invention

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects. (1) According to the process flow and equipment adopted by the present invention, the production volume of high-purity acetic acid is high, the product quality is stable, industrial production is easy, and the practicality is high. It reduces the number of precision distillations, cuts energy consumption, and the separation process is simple without causing additional environmental pollution problems. (2) The present invention can effectively remove organic impurities in acetic acid by adsorbing with a specific modified cellulose and a nitrogen-sulfur-molybdenum-doped carbon adsorbent, thereby avoiding the problem that cannot be separated by distillation due to the organic-water azeotrope.

Embodiments for Carrying Out the Invention

[0026] The following examples are merely examples included in the present invention and do not limit the scope of implementation in any way.

[0027] Example 1 In the purification process of ultra-high purity acetic acid, specifically, first, industrial acetic acid with a concentration of 70% was subjected to rough distillation to collect a fraction at 118 - 119°C, and the water content was controlled to be less than 1%. The fraction was cooled to 50°C and supplied to an adsorption column filled with modified carboxylated cellulose and a nitrogen-sulfur-molybdenum-doped carbon adsorbent. The adsorbed acetic acid liquid entered a precision distillation apparatus. The precision distillation conditions were that the number of trays was 60, the top pressure was 0.21 MPa, the top temperature was 120°C, the bottom pressure was 0.29 MPa, the bottom temperature was 142°C, and the reflux ratio was 4. After the acetic acid flowed out from the top of the column, it was filtered by an electronic grade filter, and thereby ultra-high purity acetic acid was obtained.

[0028] The manufacturing method of the nitrogen-sulfur-molybdenum-doped carbon adsorbent is as follows. In the first step, activated carbon was immersed in hydrogen peroxide water with an immersion time of 4 h, the concentration of hydrogen peroxide water was 30%, and after immersion, it was filtered and dried under drying conditions of 105°C for 6 h to obtain activated carbon after activation. In the second step, the activated carbon after activation was added to a mixed dispersion liquid containing ammonium molybdate, thiourea, and urea, and the mass ratio of activated carbon, ammonium molybdate, thiourea, and urea was 6:2:3.6:1, and it was stirred for 24 h. The mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave and heated at 200°C for 24 hours, and then naturally cooled to room temperature. After filtration, it was washed at least 3 times alternately with deionized water and ethanol, and then dried to obtain a nitrogen-sulfur-molybdenum-doped carbon adsorbent.

[0029] The steps for modifying carboxylated cellulose with tetraethylenepentamine are as follows: Carboxylated cellulose was dispersed in deionized water, N-hydroxysuccinimide and EDC were added and stirred at room temperature, then n-hexylamine was added and reacted at 70°C for 6 hours, and then tetraethylenepentamine was added and reacted at room temperature for 48 hours. The mixture was then separated and dried to obtain modified carboxylated cellulose. The mass ratio of cellulose, N-hydroxysuccinimide and EDC, n-hexylamine and tetraethylenepentamine was 100:100:6:24. The cellulose had an average length of 700 nm and an average aspect ratio of 160.

[0030] The mixing ratio of nitrogen / sulfur / molybdenum-doped carbon adsorbent to carboxylated cellulose modified with tetraethylenepentamine was 1:1.

[0031] Example 2 In the purification process for ultra-high purity acetic acid, specifically, industrial acetic acid at a concentration of 70% was first crudely distilled to collect a fraction at 118-119°C, with the water content controlled to less than 1%. The fraction was cooled to 50°C and fed into an adsorption column packed with modified carboxylated cellulose and nitrogen, sulfur, and molybdenum-doped carbon adsorbent. The adsorbed acetic acid liquid was then entered into a precision distillation apparatus. The precision distillation conditions were 60 trays, a top pressure of 0.21 MPa, a top temperature of 120°C, a boiler pressure of 0.29 MPa, a boiler temperature of 142°C, and a reflux ratio of 4. After effluent from the top of the column, the acetic acid was filtered through an electronic-grade filter to obtain ultra-high purity acetic acid.

[0032] The method for producing a nitrogen-sulfur-molybdenum-doped carbon adsorbent is as follows: In the first step, activated carbon was immersed in hydrogen peroxide solution for 4 hours at a hydrogen peroxide concentration of 30%, filtered after immersion, and dried at 105°C for 6 hours to obtain activated activated carbon. In the second step, the activated activated carbon was added to a mixed dispersion containing ammonium molybdate, thiourea, and urea, with a mass ratio of activated carbon, ammonium molybdate, thiourea, and urea of ​​6:2:3.6:1, stirred for 24 hours, and the mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave, heated at 200°C for 24 hours, and allowed to cool naturally to room temperature. After filtration, it was washed at least three times alternately with deionized water and ethanol, and then dried to obtain a nitrogen-sulfur-molybdenum-doped carbon adsorbent.

[0033] The steps for modifying carboxylated cellulose with tetraethylenepentamine are as follows: Carboxylated cellulose was dispersed in deionized water, N-hydroxysuccinimide and EDC were added and stirred at room temperature, then n-hexylamine was added and reacted at 70°C for 6 hours, and then tetraethylenepentamine was added and reacted at room temperature for 48 hours. The mixture was then separated and dried to obtain modified carboxylated cellulose. The mass ratio of cellulose, N-hydroxysuccinimide and EDC, n-hexylamine and tetraethylenepentamine was 100:100:6:24. The cellulose had an average length of 700 nm and an average aspect ratio of 160.

[0034] The mixing ratio of nitrogen / sulfur / molybdenum-doped carbon adsorbent to carboxylated cellulose modified with tetraethylenepentamine was 1:4.

[0035] Example 3 In the purification process for ultra-high purity acetic acid, specifically, industrial acetic acid at a concentration of 70% was first crudely distilled to collect a fraction at 118-119°C, with the water content controlled to less than 1%. The fraction was cooled to 50°C and fed into an adsorption column packed with modified carboxylated cellulose and nitrogen, sulfur, and molybdenum-doped carbon adsorbent. The adsorbed acetic acid liquid was then entered into a precision distillation apparatus. The precision distillation conditions were 60 trays, a top pressure of 0.21 MPa, a top temperature of 120°C, a boiler pressure of 0.29 MPa, a boiler temperature of 142°C, and a reflux ratio of 4. After effluent from the top of the column, the acetic acid was filtered through an electronic-grade filter to obtain ultra-high purity acetic acid.

[0036] The method for producing a nitrogen-sulfur-molybdenum-doped carbon adsorbent is as follows: In the first step, activated carbon was immersed in hydrogen peroxide solution for 4 hours at a hydrogen peroxide concentration of 30%, filtered after immersion, and dried at 105°C for 6 hours to obtain activated activated carbon. In the second step, the activated activated carbon was added to a mixed dispersion containing ammonium molybdate, thiourea, and urea, with a mass ratio of activated carbon, ammonium molybdate, thiourea, and urea of ​​6:2:3.6:1, stirred for 24 hours, and the mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave, heated at 200°C for 24 hours, and allowed to cool naturally to room temperature. After filtration, it was washed at least three times alternately with deionized water and ethanol, and then dried to obtain a nitrogen-sulfur-molybdenum-doped carbon adsorbent.

[0037] The steps for modifying carboxylated cellulose with tetraethylenepentamine are as follows: Carboxylated cellulose was dispersed in deionized water, N-hydroxysuccinimide and EDC were added and stirred at room temperature, then n-hexylamine was added and reacted at 70°C for 6 hours, and then tetraethylenepentamine was added and reacted at room temperature for 48 hours. The mixture was then separated and dried to obtain modified carboxylated cellulose. The mass ratio of cellulose, N-hydroxysuccinimide and EDC, n-hexylamine and tetraethylenepentamine was 100:100:6:24. The cellulose had an average length of 700 nm and an average aspect ratio of 160.

[0038] The mixing ratio of nitrogen / sulfur / molybdenum-doped carbon adsorbent to carboxylated cellulose modified with tetraethylenepentamine was 4:1.

[0039] Comparative Example 1 In the purification process for ultra-high purity acetic acid, specifically, industrial acetic acid at a concentration of 70% was first crudely distilled to collect a fraction at 118-119°C, with the water content controlled to less than 1%. The fraction was cooled to 50°C and fed into an adsorption column packed with modified carboxylated cellulose. The adsorbed acetic acid liquid was then entered into a precision distillation apparatus. The precision distillation conditions were 60 trays, a top pressure of 0.21 MPa, a top temperature of 120°C, a boiler pressure of 0.29 MPa, a boiler temperature of 142°C, and a reflux ratio of 4. After effluent from the top of the column, the acetic acid was filtered through an electronic-grade filter to obtain ultra-high purity acetic acid.

[0040] The steps for modifying carboxylated cellulose with tetraethylenepentamine are as follows: Carboxylated cellulose was dispersed in deionized water, N-hydroxysuccinimide and EDC were added and stirred at room temperature, then n-hexylamine was added and reacted at 70°C for 6 hours, and then tetraethylenepentamine was added and reacted at room temperature for 48 hours. The mixture was then separated and dried to obtain modified carboxylated cellulose. The mass ratio of cellulose, N-hydroxysuccinimide and EDC, n-hexylamine and tetraethylenepentamine was 100:100:6:24. The cellulose had an average length of 700 nm and an average aspect ratio of 160.

[0041] Comparative Example 2 In the purification process for ultra-high purity acetic acid, specifically, industrial acetic acid at a concentration of 70% was first crudely distilled to collect a fraction at 118-119°C, with the water content controlled to less than 1%. The fraction was cooled to 50°C and fed into an adsorption column packed with nitrogen, sulfur, and molybdenum-doped carbon adsorbent. The adsorbed acetic acid liquid was then entered into a precision distillation apparatus. The precision distillation conditions were 60 trays, a top pressure of 0.21 MPa, a top temperature of 120°C, a boiler pressure of 0.29 MPa, a boiler temperature of 142°C, and a reflux ratio of 4. After effluent from the top of the column, the acetic acid was filtered through an electronic-grade filter to obtain ultra-high purity acetic acid.

[0042] The method for producing a nitrogen-sulfur-molybdenum-doped carbon adsorbent is as follows: In the first step, activated carbon was immersed in hydrogen peroxide solution for 4 hours at a hydrogen peroxide concentration of 30%, filtered after immersion, and dried at 105°C for 6 hours to obtain activated activated carbon. In the second step, the activated activated carbon was added to a mixed dispersion containing ammonium molybdate, thiourea, and urea, with a mass ratio of activated carbon, ammonium molybdate, thiourea, and urea of ​​6:2:3.6:1, stirred for 24 hours, and the mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave, heated at 200°C for 24 hours, and allowed to cool naturally to room temperature. After filtration, it was washed at least three times alternately with deionized water and ethanol, and then dried to obtain a nitrogen-sulfur-molybdenum-doped carbon adsorbent.

[0043] Comparative Example 3 In the purification process for ultra-high purity acetic acid, specifically, industrial acetic acid at a concentration of 70% was first crudely distilled to collect a fraction at 118-119°C, with the water content controlled to less than 1%. The fraction was cooled to 50°C and fed into an adsorption column packed with modified carboxylated cellulose and sulfur-molybdenum-doped carbon adsorbent. The adsorbed acetic acid liquid was then entered into a precision distillation apparatus. The precision distillation conditions were 60 trays, a top pressure of 0.21 MPa, a top temperature of 120°C, a boiler pressure of 0.29 MPa, a boiler temperature of 142°C, and a reflux ratio of 4. After effluent from the top of the column, the acetic acid was filtered through an electronic-grade filter to obtain ultra-high purity acetic acid.

[0044] The method for producing the sulfur-molybdenum-doped carbon adsorbent is as follows: In the first step, activated carbon was immersed in hydrogen peroxide solution for 4 hours at a hydrogen peroxide concentration of 30%, filtered after immersion, and dried at 105°C for 6 hours to obtain activated activated carbon. In the second step, the activated activated carbon was added to a mixed dispersion containing ammonium molybdate and thiourea, with a mass ratio of activated carbon, ammonium molybdate, and thiourea of ​​6:2:3.6, stirred for 24 hours, and the mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave, heated at 200°C for 24 hours, and allowed to cool naturally to room temperature. After filtration, it was washed at least three times alternately with deionized water and ethanol, and then dried to obtain the sulfur-molybdenum-doped carbon adsorbent.

[0045] The steps for modifying carboxylated cellulose with tetraethylenepentamine are as follows: Carboxylated cellulose was dispersed in deionized water, N-hydroxysuccinimide and EDC were added and stirred at room temperature, then n-hexylamine was added and reacted at 70°C for 6 hours, and then tetraethylenepentamine was added and reacted at room temperature for 48 hours. The mixture was then separated and dried to obtain modified carboxylated cellulose. The mass ratio of cellulose, N-hydroxysuccinimide and EDC, n-hexylamine and tetraethylenepentamine was 100:100:6:24. The cellulose had an average length of 700 nm and an average aspect ratio of 160.

[0046] The mixing ratio of sulfur-molybdenum-doped carbon adsorbent to carboxylated cellulose modified with tetraethylenepentamine was 1:1.

[0047] Measurement method The method for measuring the mass fraction of acetate is as follows: A test was performed using an automatic titrator. Specifically, 1 g of the sample was accurately weighed, purified water was added, and the volume was adjusted to 250 ml in a volumetric flask. 10 ml of the reagent and 70 ml of water were then separated and titrated to the endpoint using a sodium hydroxide standard solution in the titrator, while simultaneously performing a blank test.

[0048] The mass fractions of metal ions were measured using an inductively coupled plasma mass spectrometer (ICP-MS). 5 g of the sample was weighed to an accuracy of 0.01 g, slowly placed into a 50 mL volumetric flask containing a small amount of ultrapure water, cooled to room temperature, diluted to the mark with water, and mixed uniformly by shaking. Under the same analytical conditions as the standard solution series, the signal intensity of each element in the sample was measured, and a blank test was performed simultaneously. The mass fractions of aluminum, arsenic, barium, boron, cadmium, calcium, chromium, cobalt, copper, gold, iron, lead, lithium, magnesium, manganese, nickel, potassium, silver, sodium, thallium, tin, titanium, vanadium, zinc, platinum, and antimony were measured.

[0049] Particle measurements were performed using a laser liquid particle counter.

[0050] The total concentrations of organic impurities, including acetaldehyde, 2-butenal, and 2-ethyl-2-butenal, were quantitatively measured by GC-MS analysis (gas chromatography-mass spectrometry).

[0051] The specific test data is shown in Table 1. TIFF2026054459000001.tif89170

[0052] The above examples and test data are merely some applications and embodiments of the present invention and do not limit the scope of protection of the present invention. From the above description, those skilled in the art will understand that the present invention was created by innovative concepts and means and possesses remarkable practicality and creativity.

Claims

1. A process for producing ultra-high purity acetic acid, Crude distillation: Using industrial acetic acid as a raw material, crude distillation is performed to control the water content to 3% or less (step 1), Adsorption: Step (2) involves controlling the temperature of the acetic acid after crude distillation to 40-50°C and adsorbing and filtering it with modified cellulose and nitrogen / sulfur / molybdenum-doped carbon adsorbent, Precision distillation: Step (3) involves precision distillation of the adsorbed acetic acid to collect the fraction, The process includes (4) cooling the fraction and then filtering it to obtain ultra-high purity acetic acid, The step of producing modified cellulose includes modifying carboxylated cellulose with tetraethylenepentamine to obtain modified cellulose. The manufacturing step of the nitrogen-sulfur-molybdenum-doped carbon adsorbent is a process for producing ultra-high purity acetic acid, comprising preparing a dispersion using a nitrogen source, a molybdenum source, a sulfur source, and activated carbon, and carrying out a hydrothermal reaction in a sealed environment.

2. The process according to claim 1, characterized in that the filtration is performed using an electronic-grade filter.

3. The process according to claim 1, characterized in that the hydrothermal reaction temperature is 190 to 210°C.

4. The process according to claim 1, characterized in that the molybdenum source is at least one of ammonium paramolybdate and ammonium molybdate.

5. The process according to claim 1, characterized in that the sulfur source is at least one of thiourea, thioacetamide, and ammonium sulfide.

6. The process according to claim 3, characterized in that the hydrothermal reaction temperature is 200°C.

7. The process according to claim 1, characterized in that the nitrogen source is at least one of urea and triethylamine.

8. The process according to claim 1, characterized in that the activated carbon is activated carbon that has undergone activation treatment.

9. The process according to claim 1, characterized in that the average length of the cellulose is 800 nm or less.

10. The process according to claim 1, characterized in that the average aspect ratio of the cellulose is 300 or less.

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