Ultraclean high-purity electronic-grade acetone and a preparation method thereof

Abstract

This invention discloses a method for preparing ultra-clean, high-purity electronic-grade acetone, belonging to the field of acetone refining technology. The method includes the following steps: pre-purification, selective complexation, low-temperature plasma oxidation, three-stage extraction-vacuum distillation, composite adsorption-membrane permeation coupled dehydration, and three-stage gradient demicronization. This invention utilizes a step-by-step impurity removal process to synergistically remove multiple impurities such as metal ions, moisture, aldehydes, and particulate matter. The final acetone obtained has a purity ≥99.995 wt%, moisture ≤5 ppm, single metal ion content ≤5 ppb, ≥0.1 μm particle content ≤5 particles / mL, aldehyde content ≤0.5 ppm, and evaporation residue ≤0.5 ppm, fully complying with SEMIG4 standards. This invention features a continuous process flow, thorough impurity removal, and controllable energy consumption, making it suitable for applications in semiconductors, high-end electronics, and precision analysis fields with stringent acetone purity requirements.

Description

Technical Field

[0001] This invention relates to the field of acetone refining technology, specifically to an ultra-clean, high-purity electronic-grade acetone and its preparation method. Background Technology

[0002] Ultra-pure electronic-grade acetone is a high-purity organic solvent that has undergone ultra-purification to meet the stringent requirements of microelectronics manufacturing. It is a core category of wet electronic chemicals and is widely used in high-tech industries such as semiconductors, display panels, photovoltaics, and lithium batteries. As an upstream raw material for acetone refining, industrial-grade acetone is one of the world's largest-produced basic organic chemical raw materials. Its production process is well-established, and large-scale production currently relies mainly on two mainstream routes: the cumene process and the direct oxidation / dehydrogenation process.

[0003] Regardless of the process employed, while conventional purification steps such as azeotropic distillation and ordinary distillation can improve the bulk purity of acetone to industrial grade (≥99.5wt%), their ability to remove trace / ultra-trace impurities is limited. Residual metal ions can lead to decreased gate oxide integrity and increased leakage current in semiconductor devices; reactive organic compounds such as aldehydes can cause side reactions during photolithography, affecting linewidth; particulate matter can cause patterning defects; and moisture affects solvent volatility and cleaning effectiveness. Therefore, to further purify industrial acetone into ultra-clean, high-purity electronic-grade acetone that meets SEMIG4 and higher standards, an innovative purification process capable of systematically and deeply removing multiple types of impurities must be designed.

[0004] Existing methods for preparing ultra-clean, high-purity electronic-grade acetone have several limitations: some methods employ a "distillation + drying + membrane separation" process, which, while improving purity, has limited effectiveness in removing trace metal ions and submicron-sized particles; others remove organic impurities through "oxidation + alkali treatment + distillation," but strong oxidants can easily leave residues leading to secondary pollution, and particle removal relies on conventional filtration, which cannot completely remove fine particles; furthermore, existing processes generally suffer from high energy consumption, complex procedures, and insufficient targeting of impurity removal, making it difficult to stably produce ultra-clean, high-purity electronic-grade acetone that meets the SEMIG4 standard. Therefore, developing an innovative process for preparing ultra-clean, high-purity electronic-grade acetone that achieves comprehensive impurity removal, controllable energy consumption, and stable compliance with the SEMIG4 standard has significant industrial application value and technological breakthrough implications. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-clean, high-purity electronic-grade acetone and its preparation method, in order to solve the problems of limited removal efficiency of trace metal ions and submicron particles, easy residue of strong oxidants, high energy consumption, and complex processes in the existing acetone purification process.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing ultra-clean, high-purity electronic-grade acetone includes the following steps: S1: Industrial-grade acetone is filtered through a precision filter and then passed into an adsorption column filled with mesoporous silica-supported triethylenetetramine adsorbent for pre-purification. S2: Add a complex complexing agent to the pre-purified acetone, stir to form a complex of metal ions, and then pass it through a ceramic membrane for microfiltration to selectively remove impurities through complexation. S3: The complexed and impurity-removed acetone is introduced into the plasma reaction device for low-temperature plasma oxidation in the presence of a carrier gas; S4: The oxidized acetone is subjected to first-stage extractive distillation, second-stage extractive distillation and third-stage vacuum distillation in sequence to obtain distilled acetone; S5: The acetone after distillation is sequentially dehydrated by adsorption with a composite adsorbent and dehydrated by permeation through a ceramic membrane, performing a composite adsorption-membrane permeation coupled dehydration process; S6: The dehydrated acetone is filtered sequentially through three filter cartridges of 0.5μm, 0.1μm and 0.05μm to perform three-stage gradient departicle removal, resulting in ultra-clean high-purity electronic-grade acetone.

[0008] Furthermore, in the pre-purification step, the acetone flow rate is 5-8 L / h, the column temperature is 20-25℃, and the loading mass ratio of mesoporous silica to triethylenetetramine is 10:1-1.5.

[0009] Furthermore, in the selective complexation step, the amount of composite complexing agent added is 0.05-0.1 wt% of the pre-purified acetone mass, the complexation temperature is 30-35℃, the stirring time is 1-2 h, and the pore size of the ceramic membrane is 0.1 μm; the composite complexing agent is composed of 18-crown ether-6 and disodium ethylenediaminetetraacetate in a weight ratio of 1:2-3.

[0010] Furthermore, in the low-temperature plasma oxidation step, the carrier gas is argon, the flow rate is 10-15 mL / min, the plasma power is 50-80 W, the processing time is 30-60 min, and the temperature is 30-40 °C.

[0011] Furthermore, in the three-stage extraction-vacuum distillation step, the composite extractant for the first-stage extraction distillation is composed of ethylene glycol dimethyl ether and 1-butyl-3-methylimidazolium hexafluorophosphate at a volume ratio of 3:1, and the mass ratio of acetone to the composite extractant is 10:1. The top temperature is 50-52℃, the bottom temperature is 65-70℃, and the reflux ratio is 5-7:1. The composite extractant is supplemented in the second-stage extraction distillation, the top temperature is 48-50℃, the bottom temperature is 62-65℃, and the reflux ratio is 4-6:1. The absolute pressure of the third-stage vacuum distillation is 10-30 kPa, the top temperature is 35-40℃, the bottom temperature is 55-60℃, and the reflux ratio is 8-10:1.

[0012] Furthermore, in the composite adsorption-membrane permeation coupled dehydration step, the composite adsorbent is composed of 13X molecular sieve and UiO-66 metal-organic framework material in a weight ratio of 1-3:1, the initial dehydration flow rate is 4-6 L / h, and the column temperature is 20-25℃; the ceramic membrane is made of alumina, the operating temperature is 60-70℃, the operating pressure is 0.3-0.5 MPa, and the permeate side pressure is 10-15 kPa.

[0013] Furthermore, in the three-stage gradient de-particle removal process, the first stage uses a 0.5 μm PTFE filter element, the second stage uses a 0.1 μm PTFE filter element, and the third stage uses a 0.05 μm PTFE dual-core redundant filter element.

[0014] Furthermore, the final ultra-clean, high-purity electronic-grade acetone meets the SEMI G4 standard.

[0015] An ultra-clean, high-purity electronic-grade acetone is prepared using the method described above.

[0016] Furthermore, the acetone purity is ≥99.995wt%, water content is ≤5ppm, single metal ion content is ≤5 ppb, particle content ≥0.1μm is ≤5 / mL, aldehyde content is ≤0.5ppm, and evaporation residue is ≤0.5ppm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) Comprehensive removal of impurities. This invention uses a step-by-step process of pre-purification, selective complexation, low-temperature plasma oxidation, three-stage extraction-vacuum distillation, composite adsorption-membrane permeation coupled dehydration, and three-stage gradient demicronization to specifically remove various types of impurities such as metal ions, aldehyde organic matter, moisture and particles, thereby achieving synergistic deep purification; (2) High product purity. After the above process, the final acetone purity is ≥99.995wt%, water content ≤5ppm, single metal ion content ≤5ppb, ≥0.1μm particle content ≤5 / mL, aldehyde compound content ≤0.5ppm, and evaporation residue ≤0.5ppm, fully complying with SEMIG4 standard; (3) The process conditions are mild and the energy consumption is controllable. The low-temperature plasma oxidation, vacuum distillation and other units are all carried out under mild conditions to avoid secondary pollution caused by strong oxidant residues; the composite adsorbent can be repeatedly regenerated, and the regeneration cycle is not less than 3 months, which effectively reduces the overall production cost; (4) The process sequence is reasonable and the synergistic effect is significant. Each unit is set up in sequence according to the characteristics of impurities. First, interfering impurities are removed, then targeted deep purification is carried out, and finally fine purification is carried out to avoid mutual interference between processes and ensure that the final product indicators are stable and reliable. Attached Figure Description

[0018] Figure 1This is a flowchart of a method for preparing ultra-clean, high-purity electronic-grade acetone according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1 This invention provides a technical solution: an ultra-clean, high-purity electronic-grade acetone and its preparation method, comprising the following steps: pre-purification, selective complexation, low-temperature plasma oxidation, three-stage extraction-vacuum distillation, composite adsorption-membrane permeation coupled dehydration, and three-stage gradient demicronization. This invention, through a step-by-step impurity removal process, synergistically removes multiple impurities such as metal ions, moisture, aldehydes, and particulate matter. The final acetone obtained has a purity ≥99.995wt%, moisture ≤5ppm, single metal ion content ≤5ppb, ≥0.1μm particle content ≤5 / mL, aldehyde compound content ≤0.5ppm, and evaporation residue ≤0.5ppm, fully complying with SEMIG4 standards.

[0021] Example 1.

[0022] S1: Pre-purification

[0023] Industrial-grade acetone (99.5 wt% purity) was filtered through a 0.2 μm PTFE precision filter and then passed into an adsorption column packed with mesoporous silica-supported triethylenetetramine adsorbent at a flow rate of 6 L / h. The column temperature was 22 °C, resulting in pre-purified acetone. The mass ratio of mesoporous silica to triethylenetetramine was 10:1.2.

[0024] S2: Selective complexation

[0025] Add 0.08 wt% of a complexing agent (composed of 18-crown ether-6 and EDTA-2Na in a weight ratio of 1:2.5) to pre-purified acetone, stir at 32°C for 1.5 h to allow the complexing agent to form a stable complex with the metal ions, and then microfilter through an alumina ceramic membrane with a pore size of 0.1 μm to obtain acetone after complexing and impurity removal.

[0026] S3: Low-temperature plasma oxidation

[0027] After complexation and impurity removal, acetone was introduced into a plasma reaction apparatus. Argon gas was introduced as a carrier gas at a flow rate of 12 mL / min under normal pressure and 35°C. The plasma power was set to 60 W and the treatment time was 45 min to obtain oxidized acetone.

[0028] S4: Three-stage extraction-vacuum distillation

[0029] First-stage extractive distillation: Oxidized acetone is mixed with a composite extractant (ethylene glycol dimethyl ether and 1-butyl-3-methylimidazolium hexafluorophosphate in a volume ratio of 3:1) in a mass ratio of 10:1, and then fed into a first-stage distillation column. The column top temperature is controlled at 51°C, the column bottom temperature at 68°C, and the reflux ratio at 6:1. The distillation is carried out under atmospheric pressure.

[0030] Secondary extractive distillation: The primary distillate fraction is fed into a secondary distillation column, and a composite extractant is added (1 / 3 of the amount of the primary extractant). The column top temperature is controlled at 49°C, the column bottom temperature at 63°C, the reflux ratio at 5:1, and the distillation is carried out under atmospheric pressure.

[0031] Three-stage vacuum distillation: The second-stage distillate is fed into a three-stage distillation column, with the absolute pressure controlled at 20 kPa, the top temperature at 38°C, the bottom temperature at 58°C, and the reflux ratio at 9:1. The top fraction is collected to obtain acetone after distillation.

[0032] S5: Composite adsorption-membrane permeation coupled dehydration

[0033] Preliminary dehydration: Acetone after distillation is passed into an adsorption column packed with a composite adsorbent at a flow rate of 5 L / h. The composite adsorbent is composed of 13X molecular sieve (spherical, d=4 mm) and UiO-66 (specific surface area 1000 m² / g, pore size 0.6 nm) in a weight ratio of 2:1, and the column temperature is 22℃.

[0034] Deep dehydration: The pre-dehydrated acetone was passed into an alumina ceramic membrane permeation device at an operating temperature of 65℃, an operating pressure of 0.4MPa, and a permeation side pressure of 12kPa to obtain dehydrated acetone, which was found to have a moisture content of 3.2ppm.

[0035] S6: Three-level gradient demicronization

[0036] The dehydrated acetone was passed through a three-stage filtration system: the first stage used a 0.5μm PTFE filter element, the second stage used a 0.1μm PTFE filter element, and the third stage used a 0.05μm PTFE dual-core redundant filter element to obtain de-particle-free acetone. The content of ≥0.1μm particles was measured to be 3 particles / mL.

[0037] The final ultra-clean, high-purity electronic-grade acetone product was tested and its performance indicators are as follows: purity 99.998wt% (anhydrous), moisture 3.2ppm, single metal ion content ≤0.05ppb, aldehyde content 0.4ppm, evaporation residue 0.3ppm, and ≥0.1μm particle content 3 particles / mL, fully meeting the requirements of SEMIG4 standard.

[0038] Example 2.

[0039] This embodiment aims to verify the synergistic effect and ratio optimization of the complexing agent. Based on Example 1, a comparative experiment on the complexation steps was conducted. The acetone pre-purified by S1 was divided into four groups and treated with different complexing agents:

[0040] Experimental group 2-1: Only 0.08wt% EDTA-2Na was added, and the mixture was stirred at 35℃ for 1.5h.

[0041] Experimental group 2-2: Only 0.08wt% of 18-crown ether-6 was added, and the mixture was stirred at 35℃ for 1.5h.

[0042] Experimental group 2-3: Add 0.08wt% of composite complexing agent (18-crown ether-6:EDTA-2Na=1:2), stir at 35℃ for 1.5h.

[0043] Experimental groups 2-4: Add 0.08wt% of composite complexing agent (18-crown ether-6:EDTA-2Na=1:3) and stir at 35℃ for 1.5h.

[0044] Control group (Example 1): 0.08 wt% of complexing agent (18-crown ether-6:EDTA-2Na=1:2.5) was added and stirred at 35°C for 1.5 h.

[0045] After complexation, each group was microfiltered through a 0.1 μm ceramic membrane to obtain complexed and impurity-removed acetone. Subsequent steps were the same as in Example 1.

[0046] The complexation conditions and key indicators of the final product for each group are as follows:

[0047] Table 1. Metal ion detection results of the final product

[0048] Table 2. Test results of other parameters of the final product

[0049] The results showed that 18-crown ether-6 is effective against alkali metal ions ( EDTA-2Na exhibits highly selective inclusion properties for multivalent metal ions (…). (etc.) have strong chelating ability, and the two can achieve broad-spectrum metal ion removal when combined; when the ratio of EDTA-2Na in the composite complexing agent is increased to 1:3, the metal ion removal effect is close to the optimal level, but it does not further significantly improve the product purity and particle control level. Considering both cost and effect, the 1:2.5 ratio used in Example 1 has better overall performance.

[0050] Example 3.

[0051] To compare the effects of different demicronization processes, this embodiment uses three methods to replace the three-stage gradient demicronization system in this invention: single-stage deep polypropylene filter cartridge filtration, two-stage PTFE filter cartridges of the same precision in series filtration, and three-stage gradient elution filtration of 0.5μm→0.1μm→0.1μm. The remaining process steps are exactly the same as in Example 1.

[0052] Experimental Group 3-1: The acetone dehydrated in Example 1 was passed through a deep polypropylene filter cartridge with a nominal precision of 0.1 μm (structure: asymmetric deep filtration, nominal rejection rate ≥99.9%). The product was collected directly after filtration without further filtration treatment.

[0053] Experimental Group 3-2: The acetone dehydrated in Example 1 was sequentially filtered through two stages of 0.1μm PTFE filter cartridges in series (without pre-filtration and terminal high-precision filtration unit). Particulate matter was removed by repeated filtration with the same precision to obtain the final product.

[0054] Experimental Group 3-3: The acetone dehydrated in Example 1 was sequentially passed through a 0.5μm PTFE filter, a 0.1μm PTFE filter, and a 0.1μm PTFE dual-core redundant filter to obtain the final product.

[0055] Table 3. Test results of various parameters of the final product under different particle removal processes.

[0056] The results show that the three-stage gradient de-particle system adopted in this invention, through the stepped design of pre-filtration (0.5μm) → main filtration (0.1μm) → terminal redundant filtration (0.05μm), can not only protect the downstream filter element and extend its service life, but also ensure efficient and stable retention of particles ≥0.1μm. The particle content of the final product is significantly better than other comparative solutions.

[0057] Example 4.

[0058] To verify the rationality of the six-step process sequence of this invention—"pre-purification - selective complexation - low-temperature plasma oxidation - three-stage extraction vacuum distillation - composite adsorption membrane permeation dehydration - three-stage gradient demicronization"—this embodiment conducts a comparative experiment to optimize the process sequence. A control group was constructed by shuffling the order of key units and omitting core steps to compare the impurity removal efficiency and purity of products under different process routes.

[0059] Except for the difference in the sequence / completeness of the process units, all other experimental parameters (raw material specifications, reagent dosage, temperature, pressure, flow rate, etc.) are completely consistent with those in Example 1, ensuring the validity of the comparison.

[0060] This embodiment consists of 5 groups, with the experimental group following the original process sequence, and the control groups 1-4 having their core unit order shuffled or key steps omitted respectively. The experimental results are shown in the table below: Table 4. Test results of various parameters of the final product after shuffling the order of core units or omitting key steps.

[0061] The results showed that: Control group 1, due to prior plasma oxidation, generated small-molecule polar impurities that competed with the complexing agent for metal ions, reducing the complexation efficiency; Control group 2, with distillation followed by oxidation, easily triggered slight polymerization of acetone, producing polymer impurities that were difficult to separate; Control group 3, with dehydration followed by distillation, experienced a temperature increase during distillation, causing acetone to form an azeotrope with trace amounts of water, reintroducing moisture; Control group 4, omitting the pre-purification step, resulted in large, unremoved impurities abrading the subsequent adsorbent and membrane elements, releasing more metal ions and particles. The experimental group (the process sequence of this invention) exhibited the best performance, with all indicators meeting the SEMIG4 standard, demonstrating the synergistic effect of step-by-step impurity removal.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing ultra-clean, high-purity electronic-grade acetone, characterized in that, Includes the following steps: S1: Industrial-grade acetone is filtered through a precision filter and then passed into an adsorption column filled with mesoporous silica-supported triethylenetetramine adsorbent for pre-purification. S2: Add a complex complexing agent to the pre-purified acetone, stir to form a complex of metal ions, and then pass it through a ceramic membrane for microfiltration to selectively remove impurities through complexation. S3: The complexed and impurity-removed acetone is introduced into the plasma reaction device for low-temperature plasma oxidation in the presence of a carrier gas; S4: The oxidized acetone is subjected to first-stage extractive distillation, second-stage extractive distillation and third-stage vacuum distillation in sequence to obtain distilled acetone; S5: The acetone after distillation is sequentially dehydrated by adsorption with a composite adsorbent and dehydrated by permeation through a ceramic membrane, performing a composite adsorption-membrane permeation coupled dehydration process; S6: The dehydrated acetone is filtered sequentially through three filter cartridges of 0.5μm, 0.1μm and 0.05μm to perform three-stage gradient departicle removal, resulting in ultra-clean high-purity electronic-grade acetone.

2. The preparation method according to claim 1, characterized in that, In the S1 pre-purification step, the acetone flow rate is 5-8 L / h, the column temperature is 20-25℃, and the loading mass ratio of mesoporous silica to triethylenetetramine is 10:1-1.

5.

3. The preparation method according to claim 1, characterized in that, In the S2 selective complexation step, the amount of composite complexing agent added is 0.05-0.1 wt% of the pre-purified acetone mass, the complexation temperature is 30-35℃, the stirring time is 1-2 h, and the pore size of the ceramic membrane is 0.1 μm; the composite complexing agent is composed of 18-crown ether-6 and disodium ethylenediaminetetraacetate in a weight ratio of 1:2-3.

4. The preparation method according to claim 1, characterized in that, In the S3 low-temperature plasma oxidation step, the carrier gas is argon, the flow rate is 10-15 mL / min, the plasma power is 50-80 W, the processing time is 30-60 min, and the temperature is 30-40 °C.

5. The preparation method according to claim 1, characterized in that, In the S4 three-stage extraction-vacuum distillation step, the composite extractant for the first-stage extraction distillation is composed of ethylene glycol dimethyl ether and 1-butyl-3-methylimidazolium hexafluorophosphate at a volume ratio of 3:1, and the mass ratio of acetone to the composite extractant is 10:

1. The top temperature is 50-52℃, the bottom temperature is 65-70℃, and the reflux ratio is 5-7:

1. The composite extractant is supplemented in the second-stage extraction distillation, the top temperature is 48-50℃, the bottom temperature is 62-65℃, and the reflux ratio is 4-6:

1. The absolute pressure of the third-stage vacuum distillation is 10-30 kPa, the top temperature is 35-40℃, the bottom temperature is 55-60℃, and the reflux ratio is 8-10:

1.

6. The preparation method according to claim 1, characterized in that, In the S5 composite adsorption-membrane permeation coupled dehydration step, the composite adsorbent is composed of 13X molecular sieve and UiO-66 metal-organic framework material in a weight ratio of 1-3:1, the initial dehydration flow rate is 4-6 L / h, and the column temperature is 20-25℃; the ceramic membrane is made of alumina, the operating temperature is 60-70℃, the operating pressure is 0.3-0.5 MPa, and the permeation side pressure is 10-15 kPa.

7. The preparation method according to claim 1, characterized in that, In the S6 three-stage gradient de-particle removal step, the first stage uses a 0.5μm PTFE filter element, the second stage uses a 0.1μm PTFE filter element, and the third stage uses a 0.05μm PTFE dual-core redundant filter element.

8. The preparation method according to claim 1, characterized in that, The final ultra-clean, high-purity electronic-grade acetone meets the SEMI G4 standard.

9. An ultra-clean, high-purity electronic-grade acetone, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The ultra-clean, high-purity electronic-grade acetone according to claim 9, characterized in that, The acetone has a purity of ≥99.995 wt%, moisture content ≤5 ppm, single metal ion content ≤5 ppb, particle content ≥0.1μm ≤5 particles / mL, aldehyde content ≤0.5 ppm, and evaporation residue ≤0.5 ppm.

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