Electronic-grade gamma-substituted carboxylic acid as well as purification method and application thereof

Abstract

The invention provides electronic-grade gamma-substituted carboxylic acid as well as a purification method and application thereof, the purification method of the electronic-grade gamma-substituted carboxylic acid comprises the following steps: dissolving industrial-grade gamma-substituted carboxylic acid solid, then adding alpha-aminobutyric acid, and uniformly mixing to obtain a mixed solution; the mixed solution is purified through cation exchange resin and anion exchange resin, metal ions are removed, and an electronic-grade gamma-substituted carboxylic acid solution is obtained; carrying out multi-stage filtration on the electronic-grade gamma-substituted carboxylic acid solution to remove particulate matters larger than 50nm in the electronic-grade gamma-substituted carboxylic acid solution so as to obtain the electronic-grade gamma-substituted carboxylic acid solution without microparticles; and drying the electronic-grade gamma-substituted carboxylic acid solution without the microparticles to obtain an electronic-grade gamma-substituted carboxylic acid solid. The prepared electronic-grade gamma-substituted carboxylic acid has the advantages of high purity and low metal ion content, and can meet the requirements of semiconductor process raw materials.

Description

Technical Field

[0001] The present invention relates to amino acid purification technology, in particular to an electronic-grade gamma-substituted carboxylic acid, a purification method and application thereof. Background Art

[0002] As the semiconductor industry's demand for environmentally friendly and efficient cleaning technologies increases, carboxylic acid has certain market prospects in the field of semiconductor cleaning fluids.

[0003] In semiconductor cleaning fluids, carboxylic acids not only help remove organic contaminants and particulate matter from the wafer surface, but can also be used to remove metallic impurities. Carboxylic acids can regulate the pH value of the cleaning fluid, maintaining its stability and thus improving cleaning effectiveness.

[0004] However, as the semiconductor industry's requirements for integrated circuit line widths become increasingly refined, the cleanliness standards for wet electronic chemicals are becoming increasingly stringent, placing higher demands on processing equipment, materials, containers, and the production environment. Industrial-grade γ-substituted carboxylic acids, due to their strong metal ion chelating ability, have shown potential application value in semiconductor cleaning fluids. However, effectively removing metal ions from industrial-grade γ-substituted carboxylic acids to meet the high purity requirements of electronic-grade chemicals remains a major technical challenge facing the industry.

[0005] Currently, there are no published reports in China or abroad on how to use industrial-grade γ-substituted carboxylic acids as raw materials to purify high-purity electronic-grade γ-substituted carboxylic acids suitable for semiconductor cleaning fluids. This technological gap has limited the widespread application of γ-substituted carboxylic acids in the semiconductor industry. Summary of the Invention

[0006] The purpose of the present invention is to address the problem that the purity of current industrial-grade γ-substituted carboxylic acids cannot meet the high-purity requirements of semiconductor cleaning fluids, and to propose a method for purifying electronic-grade γ-substituted carboxylic acids. The electronic-grade γ-substituted carboxylic acids prepared by this method have the advantages of high purity and low metal ion content, which can meet the requirements of semiconductor cleaning fluids.

[0007] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a method for purifying electronic-grade γ-substituted carboxylic acid, comprising the following steps:

[0009] Step 1: dissolving industrial-grade γ-substituted carboxylic acid solid, then adding α-aminobutyric acid and mixing evenly to obtain a mixed solution;

[0010] Step 2: Purifying the mixed solution through a cation exchange resin and an anion exchange resin to obtain an electronic grade γ-substituted carboxylic acid solution;

[0011] Step 3: filtering the electronic-grade γ-substituted carboxylic acid solution through multiple stages to remove particles larger than 50 nm, thereby obtaining an electronic-grade γ-substituted carboxylic acid solution free of microparticles;

[0012] Step 4: drying the electronic-grade γ-substituted carboxylic acid solution from which the microparticles have been removed to obtain an electronic-grade γ-substituted carboxylic acid solid.

[0013] Furthermore, in step 1, the content of γ-substituted carboxylic acid in the industrial-grade γ-substituted carboxylic acid solid is greater than 97%, and the total metal ion content is greater than or equal to 13.5 ppm.

[0014] Furthermore, in step 1, the total metal ion content of the γ-substituted carboxylic acid in the industrial-grade γ-substituted carboxylic acid solid is 13.5 to 15.5 ppm.

[0015] Furthermore, in step 1, a solvent is used to dissolve the industrial-grade γ-substituted carboxylic acid solid, and the solvent is a mixture of ethanol and ultrapure water.

[0016] Furthermore, the mass ratio of the ethanol to ultrapure water is 1:1-4.

[0017] Furthermore, the preferred mass ratio of the ethanol to ultrapure water is 1:1.

[0018] When an excessive amount of ethanol is added, ethanol and ultrapure water will form a stronger complex, destroying the original γ-substituted carboxylic acid-water hydrogen bond complex, attracting water molecules around the γ-substituted carboxylic acid, resulting in a decrease in the solubility of the γ-substituted carboxylic acid. The γ-substituted carboxylic acid cannot hydrogen bond with water to collide and nucleate, thereby reducing the solubility.

[0019] Furthermore, in step 1, the mass ratio of the α-aminobutyric acid to the γ-substituted carboxylic acid is 1:99 to 1:10000, or the amount of the α-aminobutyric acid added is 0.01 to 1 wt.% of the γ-substituted carboxylic acid.

[0020] Furthermore, in step 1, the mass ratio of the α-aminobutyric acid to the γ-substituted carboxylic acid is 1:200 to 1:400, or the added amount of the α-aminobutyric acid is preferably 0.25 to 0.5 wt.% of the γ-substituted carboxylic acid.

[0021] When α-aminobutyric acid and γ-substituted carboxylic acid exist at the same time, α-aminobutyric acid and γ-substituted carboxylic acid produce competitive complexation. Since α-aminobutyric acid has stronger complexation ability, when α-aminobutyric acid forms a metal complex with metal ions (such as magnesium ions, calcium ions, etc.), it will be adsorbed by the cation exchange resin under acidic conditions, thereby achieving the removal of γ-substituted carboxylic acid ions (such as magnesium ions, calcium ions, etc.).

[0022] Furthermore, in step 2, the cation exchange resin is a mixture of a styrene resin containing an iminodiacetate functional group and a styrene resin containing a sulfonic acid group.

[0023] Furthermore, the mass ratio of the styrene-based resin containing iminodiacetate functional groups to the styrene-based resin containing sulfonic acid groups is 1:1-4.

[0024] Furthermore, the preferred mass ratio of the styrene-based resin containing iminodiacetate functional groups to the styrene-based resin containing sulfonic acid groups is 1:2.

[0025] Furthermore, the styrene resin containing iminodiacetate functional groups is one or more of Chelex100 resin, D401 resin and CR11 resin.

[0026] Furthermore, the styrene resin containing iminodiacetate functional groups is preferably Chelex 100 resin.

[0027] Styrenic resins containing iminodiacetate functional groups exhibit excellent mechanical properties, good chemical stability, and good thermal stability. For example, Chelex 100 resin is a styrene divinylbenzene copolymer containing paired iminodiacetate ions that can chelate multivalent metal ions. While the carboxylic acid groups of Chelex 100 resin classify it as a weak cation exchange resin, it differs from other exchangers in its class by exhibiting uniquely high metal ion selectivity and enhanced bond strength. This includes excellent selectivity for ions such as calcium and magnesium, enabling the removal of metal ions such as magnesium and calcium.

[0028] Furthermore, the styrene resin containing a sulfonic acid group is one or more of SC650CP resin, D001 resin and NKC-9 resin.

[0029] Furthermore, the styrene resin containing a sulfonic acid group is preferably SC650CP resin.

[0030] The styrene-based resin containing sulfonic acid groups has a certain degree of swelling and excellent ion exchange capacity. The sulfonic acid groups exchange with cations to remove metal ions. For example, SC650CP resin is a cation exchange resin that incorporates sulfonic acid groups (-SO3H) into a gel-structured styrene-divinylbenzene copolymer. It has good kinetic properties and exchange capacity, extremely high strength and regeneration levels, and excellent chemical and physical stability. SC650CP resin has an extremely high exchange capacity for monovalent cations such as sodium and potassium, enabling the removal of monovalent metal ions.

[0031] Furthermore, the anion exchange resin is an acrylic resin containing a quaternary ammonium group.

[0032] Furthermore, the acrylic resin containing a quaternary ammonium group is one or more of D370 resin, D211 resin, D213 resin and IRA458CL resin.

[0033] Furthermore, the acrylic resin containing a quaternary ammonium group is preferably D370 resin.

[0034] The acrylic resin containing quaternary ammonium groups has good hydrophobicity and mechanical properties. The quaternary ammonium groups can exchange with anions to remove FeCl4 -1 Anionic complexes. For example, D370 resin is an anion exchange resin with quaternary ammonium groups on a macroporous acrylic backbone. The resin's unique macroporous structure and acrylic backbone provide excellent hydrophobicity, promoting the adsorption and desorption of organic matter, and is particularly selective for iron ions.

[0035] Furthermore, in step 2, the mixed solution is passed through a cation exchange resin and an anion exchange resin at a rate of 2 to 5 L / h at room temperature.

[0036] Furthermore, the mass ratio of the mixed solution, the cation exchange resin and the anion exchange resin is 5 to 20:1:1.

[0037] Furthermore, the preferred mass ratio of the mixed solution, cation exchange resin and anion exchange resin is 5-10:1:1.

[0038] Furthermore, the preferred mass ratio of the mixed solution, cation exchange resin and anion exchange resin is 10:1:1.

[0039] The adsorption of target substances by ion exchange resins is a dynamic equilibrium process. When the ion exchange resin dosage is low, the target substance concentration per unit volume of ion exchange resin is higher, making it easier to reach adsorption saturation, resulting in more effective adsorption of the target substance. Because the adsorption capacity of ion exchange resins is limited, using a smaller amount of ion exchange resin allows the target substance to be more easily concentrated on the limited ion exchange resin, fully utilizing its adsorption capacity. Conversely, using too much ion exchange resin may result in some underutilization of the resin, resulting in wasted resources and reduced purification efficiency. A lower ratio of ion exchange resin to mixed liquor generally improves purification results. When the ratio of cation exchange resin to anion exchange resin to mixed liquor is 1:1:5 and 1:1:10, purification results are similar. Considering industrial costs, a ratio of 1:1:10 is more economical. This is primarily due to higher adsorption efficiency, improved mass transfer, stronger selective adsorption, lower costs, and higher operating efficiency.

[0040] Furthermore, in step three, the multi-stage filtration is three-stage filtration.

[0041] Furthermore, the filtration membrane of the multi-stage filtration is selected from one or more of polytetrafluoroethylene membrane, polyethersulfone membrane, polyvinylidene fluoride membrane, polyimide membrane and polyamide membrane in series.

[0042] Furthermore, the filter membrane of the multi-stage filtration is preferably a polytetrafluoroethylene membrane (PTFE).

[0043] Furthermore, in the three-stage filtration, the filtration accuracy of the first-stage filtration is 0.5-1 μm, the filtration accuracy of the second-stage filtration is 0.1-0.25 μm, and the filtration accuracy of the third-stage filtration is 10 nm-50 nm.

[0044] Furthermore, in step four, the drying method is one or more combinations of freeze drying, vacuum drying, and spray drying.

[0045] Furthermore, in step four, the drying method is freeze drying, and the drying time is 24 to 48 hours.

[0046] Furthermore, in step 4, the drying time is preferably 36 hours.

[0047] Furthermore, the used cation exchange resin and anion exchange resin are activated and regenerated and then stored in a cool place.

[0048] Furthermore, the used cation exchange resin is activated and regenerated using an acidic liquid.

[0049] Furthermore, the acidic liquid is one or more of hydrochloric acid, sulfuric acid, phosphoric acid and acetic acid.

[0050] Furthermore, the used anion exchange resin is activated and regenerated using an alkaline liquid.

[0051] Furthermore, the alkaline liquid is sodium hydroxide and / or potassium hydroxide.

[0052] Furthermore, the γ-substituted carboxylic acid has a substituent at the γ-position (i.e., the 4th carbon, numbered as C1 starting from the carboxyl carbon) of the carboxyl group (-COOH).

[0053] Furthermore, the γ-substituted carboxylic acid is any one of levulinic acid, 4-hydroxyhexanoic acid, 4-phenylpentanoic acid, 4-aminopentanoic acid, and 4-hydroxyheptanoic acid.

[0054] Another object of the present invention is to disclose an electronic grade γ-substituted carboxylic acid, which is purified by the above purification method.

[0055] Furthermore, the total metal ion content in the electronic-grade γ-substituted carboxylic acid is below 5 ppm, the content of each metal ion of Na, Mg, Al, K, Ca, Fe, and Zn is below 400 ppb, and the purity of the electronic-grade γ-substituted carboxylic acid is ≥99.53%.

[0056] Another object of the present invention is to disclose the use of an electronic-grade γ-substituted carboxylic acid in semiconductor cleaning fluids. The semiconductor cleaning fluid containing the electronic-grade γ-substituted carboxylic acid exhibits high purity, efficient metal ion chelation and particle removal capabilities, while meeting stability, environmental friendliness, and compatibility requirements.

[0057] The electronic-grade γ-substituted carboxylic acid, the purification method and the application thereof of the present invention have the following advantages compared with the prior art:

[0058] 1) The present invention creatively introduces α-aminobutyric acid during the purification process and utilizes a combination of cation exchange resin and anion exchange resin for purification, resulting in an electronic-grade γ-substituted carboxylic acid. The total ion content of the electronic-grade γ-substituted carboxylic acid is below 5 ppm, and the content of various ions (such as Na, Mg, Al, K, Ca, Fe, and Zn ions) is below 400 ppb. The purity of the γ-substituted carboxylic acid is ≥99.5%, meeting the standards required by the semiconductor industry. This enables the production of electronic-grade γ-substituted carboxylic acids from industrial-grade γ-substituted carboxylic acids.

[0059] 2) The present invention uses a cation exchange resin and an anion exchange resin to purify the mixed solution. The cation exchange resin can remove cations, and the anion exchange resin can remove negatively charged anion complexes formed by cations and other ions, such as some high-valent iron ions. By using the cation exchange resin and the anion exchange resin in combination, most of the ions in the solution are removed, thereby achieving purification of the mixed solution.

[0060] The present invention adopts a combination of a styrene resin containing iminodiacetate functional groups and a styrene resin containing sulfonic acid groups as a cation exchange resin, which can chelate metal ions in a solution and remove divalent and monovalent metal ions in the solution.

[0061] The present invention adopts acrylic resin containing quaternary ammonium groups as anionic resin, has high selectivity for iron ions, and realizes the removal of iron ions in the solution.

[0062] 3) The method for purifying electronic-grade γ-substituted carboxylic acids of the present invention can not only remove metal ions and particulate matter, but also improve the purity of the γ-substituted carboxylic acids.

[0063] 4) The present invention reduces the content of particles larger than 50 nm through multi-stage filtration, resulting in an electronic-grade γ-substituted carboxylic acid that meets the requirements of semiconductor cleaning fluids. Semiconductor cleaning fluids containing electronic-grade γ-substituted carboxylic acids exhibit high purity, efficient metal ion chelation and particle removal capabilities, while also meeting stability, environmental friendliness, and compatibility requirements. DETAILED DESCRIPTION

[0064] The present invention will be further described below with reference to the following examples. The following description of the technical features is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0065] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0066] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0067] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0068] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0069] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0070] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0071] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0072] Example 1

[0073] This embodiment discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0074] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 0.35 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0075] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 10 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution.

[0076] The cation exchange resin is a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:2; the anion exchange resin is D370 resin.

[0077] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the three-stage filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0078] Step 4: The electronic-grade 4-aminovaleric acid solution obtained in step 3, after removing microparticles, is divided into freeze-drying trays and rapidly frozen in liquid nitrogen (-196°C) to obtain a frozen sample. The frozen sample is transferred to a freeze dryer, vacuumed to 0.1 mbar, at a temperature of -15°C, and dried for 36 hours to obtain an electronic-grade 4-aminovaleric acid solid.

[0079] Example 2

[0080] This embodiment discloses a method for purifying electronic-grade levulinic acid, and the specific steps are as follows:

[0081] Step 1: 100 parts by mass of industrial-grade levulinic acid solid with a purity of 99.03% is dissolved in a solvent (the mass ratio of ethanol to ultrapure water = 1:2), and then 0.25 parts by mass of α-aminobutyric acid is added and mixed evenly to obtain a mixed solution.

[0082] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 20 parts by mass of a cation exchange resin and an adsorption column filled with 20 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade levulinic acid solution.

[0083] The cation exchange resin D401 resin and SC650CP resin are mixed in a mass ratio of 1:1; the anion exchange resin is D370 resin.

[0084] Step 3: The electronic-grade levulinic acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade levulinic acid solution with microparticles removed.

[0085] Step 4: Dispense the demicroparticle-free electronic-grade levulinic acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade levulinic acid solid.

[0086] Example 3

[0087] This embodiment discloses a method for purifying electronic-grade 4-hydroxyhexanoic acid, and the specific steps are as follows:

[0088] Step 1: Dissolve 100 parts by mass of industrial-grade 4-hydroxyhexanoic acid solid with a purity of 99.09% in a solvent (mass ratio of ethanol to ultrapure water = 1:3), then add 0.5 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0089] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing through an adsorption column filled with 8 parts by mass of a cation exchange resin and an adsorption column filled with 8 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-hydroxyhexanoic acid solution.

[0090] The cation exchange resin is a mixture of CR11 resin and D001 resin in a mass ratio of 1:3; the anion exchange resin is D370 resin.

[0091] Step 3: The electronic-grade 4-hydroxyhexanoic acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the three-stage filtration to obtain an electronic-grade 4-hydroxyhexanoic acid solution free of microparticles.

[0092] Step 4: The electronic-grade 4-hydroxyhexanoic acid solution obtained in Step 3, after demicroparticle removal, was dispensed into freeze-drying trays and rapidly frozen in liquid nitrogen (-196°C) to obtain a frozen sample. The frozen sample was transferred to a freeze dryer, vacuumed to 0.1 mbar, at a temperature of -15°C, and dried for 36 hours to obtain electronic-grade 4-hydroxyhexanoic acid solid.

[0093] Example 4

[0094] This embodiment discloses a method for purifying electronic-grade 4-phenylvaleric acid, and the specific steps are as follows:

[0095] Step 1: Dissolve 100 parts by mass of industrial-grade 4-phenylvaleric acid solid with a purity of 99.05% in a solvent (mass ratio of ethanol to ultrapure water = 1:4), then add 0.01 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0096] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 5 parts by mass of a cation exchange resin and an adsorption column filled with 5 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-phenylvaleric acid solution.

[0097] The cation exchange resin is a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:4; the anion exchange resin is D 211 resin.

[0098] Step 3: The electronic-grade 4-phenylvaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the three-stage filtration to obtain an electronic-grade 4-phenylvaleric acid solution free of microparticles.

[0099] Step 4: The electronic-grade 4-phenylvaleric acid solution obtained in Step 3, after demicroparticle removal, was dispensed into freeze-drying trays and rapidly frozen in liquid nitrogen (-196°C) to obtain a frozen sample. The frozen sample was transferred to a freeze dryer, vacuumed to 0.1 mbar, at a temperature of -15°C, and dried for 36 hours to obtain electronic-grade 4-phenylvaleric acid solid.

[0100] Example 5

[0101] This example discloses a method for purifying electronic-grade 4-hydroxyheptanoic acid, and the specific steps are as follows:

[0102] Step 1: 100 parts by mass of industrial-grade 4-hydroxyheptanoic acid solid with a purity of 99.07% was dissolved in a solvent (the mass ratio of ethanol to ultrapure water = 1:1), and then 1.01 parts by mass of α-aminobutyric acid was added and mixed uniformly to obtain a mixed solution.

[0103] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 5 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-hydroxyheptanoic acid solution.

[0104] The cation exchange resin is a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:3; the anion exchange resin is D213 resin.

[0105] Step 3: The electronic-grade 4-hydroxyheptanoic acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the three-stage filtration to obtain an electronic-grade 4-hydroxyheptanoic acid solution with microparticles removed.

[0106] Step 4: The electronic-grade 4-hydroxyheptanoic acid solution obtained in Step 3, after demicroparticle removal, was dispensed into freeze-drying trays and rapidly frozen in liquid nitrogen (-196°C) to obtain a frozen sample. The frozen sample was transferred to a freeze dryer, vacuumed to 0.1 mbar, at a temperature of -15°C, and dried for 36 hours to obtain electronic-grade 4-phenylvaleric acid solid.

[0107] Example 6

[0108] This embodiment discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0109] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 0.35 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0110] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 10 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution.

[0111] The cation exchange resin is a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:5; the anion exchange resin is D370 resin.

[0112] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0113] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0114] Example 7

[0115] This comparative example discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0116] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 0.35 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0117] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 10 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution.

[0118] The cation exchange resin is Chelex 100 resin; the anion exchange resin is D370 resin.

[0119] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0120] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0121] Example 8

[0122] This comparative example discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0123] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 0.35 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0124] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 10 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution.

[0125] The cation exchange resin is SC650CP resin; the anion exchange resin is D370 resin.

[0126] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0127] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0128] Example 9

[0129] This embodiment discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0130] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 5 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0131] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 10 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution.

[0132] The cation exchange resin is a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:2; the anion exchange resin is D370 resin.

[0133] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the three-stage filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0134] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0135] Comparative Example 1

[0136] This comparative example discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0137] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1) to obtain a mixed solution.

[0138] Step 2: At room temperature, the mixed solution obtained in step 1 was purified by passing it through an adsorption column filled with 10 parts by mass of a cation exchange resin and an adsorption column filled with 10 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution.

[0139] The cation exchange resin is a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:2; the anion exchange resin is D370 resin.

[0140] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0141] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0142] Comparative Example 2

[0143] This comparative example discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0144] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 0.35 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0145] Step 2: At room temperature, the mixed solution obtained in step 1 was passed through an adsorption column filled with 20 parts by mass of cation exchange resin at a rate of 3 L / h for purification to obtain an electronic grade 4-aminovaleric acid solution.

[0146] The cation exchange resin was a mixture of Chelex 100 resin and SC650CP resin in a mass ratio of 1:2.

[0147] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0148] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0149] Comparative Example 3

[0150] This comparative example discloses a method for purifying electronic-grade 4-aminovaleric acid, and the specific steps are as follows:

[0151] Step 1: Dissolve 100 parts by mass of industrial-grade 4-aminovaleric acid solid with a purity of 99.12% in a solvent (mass ratio of ethanol to ultrapure water = 1:1), then add 0.35 parts by mass of α-aminobutyric acid and mix well to obtain a mixed solution.

[0152] Step 2: Purify the mixed solution obtained in step 1 at room temperature by passing it through an adsorption column filled with 20 parts by mass of anion exchange resin at a rate of 3 L / h to obtain an electronic grade 4-aminovaleric acid solution. The anion exchange resin is D370 resin.

[0153] Step 3: The electronic-grade 4-aminovaleric acid solution obtained in step 2 is sequentially filtered through a PTFE membrane with a pore size of 0.5 μm for primary filtration, a PTFE membrane with a pore size of 0.1 μm for secondary filtration, and a PTFE membrane with a pore size of 50 nm for tertiary filtration. The particles larger than 50 nm in the product are removed by the tertiary filtration to obtain an electronic-grade 4-aminovaleric acid solution free of microparticles.

[0154] Step 4: Dispense the demicroparticle-free electronic-grade 4-aminovaleric acid solution obtained in Step 3 into freeze-drying trays and rapidly freeze in liquid nitrogen (-196°C) to obtain a frozen sample. Transfer the frozen sample to a freeze dryer, evacuate to 0.1 mbar, maintain a temperature of -15°C, and dry for 36 hours to obtain electronic-grade 4-aminovaleric acid solid.

[0155] The substituted carboxylic acids of Examples 1-9 and Comparative Examples 1-3 were tested respectively. The test methods and test results are as follows:

[0156] ICP-MS was used to test the metal ion content. The test results are shown in Table 1.

[0157] In the following examples, the raw materials: industrial grade γ-substituted carboxylic acids are commercially available, and the contents of various metal ions therein are shown in Table 1.

[0158] Table 1 Metal ion content

[0159]

[0160]

[0161] Table 1 shows that the electronic-grade γ-substituted carboxylic acids prepared in Examples 1-6 each contained less than 100 ppb of various metal ions, with a total metal ion content of less than 400 ppb. Examples 7 and 8 employed a combination of cation exchange resin and anion exchange resin, but the cation exchange resin was configured with only a single type, resulting in limited selectivity for adsorption of metal ions of varying valences and ultimately failing to achieve effective simultaneous removal of multivalent metal ions. In Example 9, excessive addition of α-aminobutyric acid resulted in residual α-aminobutyric acid and low purity.

[0162] Comparative Example 1, due to the lack of α-aminobutyric acid, resulted in a Ca ion concentration of 400 ppb. Comparative Example 2, due to the use of only a cation exchange resin, had a poor Fe ion removal rate. Comparative Example 3, due to the use of only an anion exchange resin, was only able to remove Fe ions, with poor removal of other metal ions.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for purifying electronic grade γ-substituted carboxylic acid, characterized in that: The following steps are involved: Step 1: dissolving industrial-grade γ-substituted carboxylic acid solid, then adding α-aminobutyric acid and mixing evenly to obtain a mixed solution; Step 2: Purifying the mixed solution through a cation exchange resin and an anion exchange resin to obtain an electronic grade γ-substituted carboxylic acid solution; Step 3: filtering the electronic-grade γ-substituted carboxylic acid solution through multiple stages to remove particles larger than 50 nm, thereby obtaining an electronic-grade γ-substituted carboxylic acid solution free of microparticles; Step 4: Drying the electronic-grade γ-substituted carboxylic acid solution from which the microparticles have been removed to obtain the electronic-grade γ-substituted carboxylic acid.

2. The method for purifying electronic-grade γ-substituted carboxylic acids according to claim 1, characterized in that: Step 1: dissolving the industrial-grade γ-substituted carboxylic acid solid in a solvent comprising a mixture of ethanol and ultrapure water; And / or, the mass ratio of the α-aminobutyric acid to the γ-substituted carboxylic acid is 1:99 to 1:10000.

3. The method for purifying electronic-grade γ-substituted carboxylic acid according to claim 1, characterized in that: Step 2: the cation exchange resin is a mixture of a styrene resin containing an iminodiacetate functional group and a styrene resin containing a sulfonic acid group; And / or, the anion exchange resin is an acrylic resin containing a quaternary ammonium group; And / or, the mass ratio of the mixed solution, the cation exchange resin and the anion exchange resin is 5 to 20:1:

1.

4. The method for purifying electronic grade γ-substituted carboxylic acid according to claim 1, characterized in that: Step 3: The multi-stage filtration membrane is selected from one or more of polytetrafluoroethylene membrane, polyethersulfone membrane, polyvinylidene fluoride membrane, polyimide membrane and polyamide membrane in series.

5. The method for purifying electronic-grade γ-substituted carboxylic acid according to claim 1, characterized in that: Step 4: The drying method is one or more combinations of freeze drying, vacuum drying, and spray drying.

6. The method for purifying electronic grade γ-substituted carboxylic acid according to claim 1, characterized in that: The used cation exchange resin is activated and regenerated using an acidic liquid, wherein the acidic liquid is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid; And / or, the used anion exchange resin is activated and regenerated using an alkaline liquid, wherein the alkaline liquid is sodium hydroxide and / or potassium hydroxide.

7. An electronic grade γ-substituted carboxylic acid, characterized in that The product is purified by the purification method according to any one of claims 1 to 7.

8. An electronic grade γ-substituted carboxylic acid according to claim 8, characterized in that: The total metal ion content in the electronic-grade gamma-substituted carboxylic acid is below 5 ppm, the content of each metal ion of Na, Mg, Al, K, Ca, Fe and Zn is below 400 ppb, and the purity of the electronic-grade gamma-substituted carboxylic acid is ≥99.53%.

9. Use of the electronic-grade γ-substituted carboxylic acid according to claim 8 or 9 in the field of semiconductor cleaning fluids.

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