Method for purifying organic solvent and device for purifying organic solvent

Abstract

Provided is a method for purifying an organic solvent and a device for purifying an organic solvent, with which it is possible to reduce the amount of impurities such as metal impurities of as many kinds as possible from the organic solvent. The method for purifying an organic solvent includes an anion exchanger contact step for bringing an organic solvent to be purified into contact with an anion exchanger A and an anion exchanger B, wherein: the anion exchanger A is an anion exchanger having at least one ionic form that is selected from the group consisting of an OH form, a free base form, a carbonate form, and a bicarbonate form; and the anion exchanger B is a chelate resin that contains a glucamine-type ion exchange group.

Description

Method for purifying organic solvents and apparatus for purifying organic solvents

[0001] The present invention relates to a method for purifying organic solvents and an apparatus for purifying organic solvents.

[0002] Commercially available general-grade and EL-grade (Electronic Grade) organic solvents contain residual impurities such as metal impurities. Organic solvents used in semiconductor manufacturing processes need to have their impurity levels reduced. In organic solvents, impurities may not be ionized compared to water, and their form is often unclear. Furthermore, because organic solvents have higher viscosity than water, when removing impurities using ion exchangers, the diffusion of impurities into the ion exchanger is poor, resulting in poor removal of cationic and anionic impurities.

[0003] Among organic solvents, metal impurities contained in isopropyl alcohol (IPA), paint thinner (for example, a mixture of propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME)), and PGMEA can be removed by ion exchangers. On the other hand, ion exchange can remove H ＋ Acidic substances such as OH － When alkaline substances such as these are released into organic solvents, it can lead to a slight increase in moisture content and alteration of the organic solvent and its coexisting substances. In particular, when treating liquids containing ester-based or ether-based organic solvents using an ion exchanger, it is known that hydrolysis may occur if the contact time between the organic solvent and the H-type strongly acidic cation group or the OH-type strongly basic anionic group is prolonged.

[0004] When reducing impurities by ion exchange, elements with low selectivity are difficult to reduce. In organic solvents, as mentioned above, impurities may not be ionized, making reduction even more difficult. Among these, boron is one of the impurities that requires optimization of the removal method because it is difficult to reduce using only cation exchange resins, which are common in metal removal. In water treatment, a common method for reducing boron is to use an ion exchange reaction with a chelate resin containing an N-methylglucamine group. As mentioned above, treatment in organic solvents is more difficult than in water, so optimization of the purification method is necessary when performing treatment to reduce boron to low concentrations of ppb or less.

[0005] For example, Patent Document 1 describes a method for purifying hydrogen peroxide, comprising: an anion exchanger conversion step (2) to obtain a mixed bed consisting of an anion exchanger (A) and a cation exchanger, by contacting carbon dioxide-dissolved water with a mixed bed consisting of an anion exchanger (B) and a cation exchanger packed in an ion exchange column, thereby converting the anion exchanger (B) to a bicarbonate ion form or an anion exchanger (A) having both bicarbonate ion and carbonate ion forms; and a hydrogen peroxide purification step to obtain purified hydrogen peroxide by supplying crude hydrogen peroxide to the ion exchange column and contacting it with the mixed bed. In the method of Patent Document 1, ionic impurities are reduced by contacting crude hydrogen peroxide with an H-type cation exchanger and an anion exchanger in the form of carbon dioxide and bicarbonate. In the example, SV10 (h －１ ), the metal concentration when hydrogen peroxide solution is passed through at 5°C, and the ionic composition of the functional groups of the anionic resin have been measured. Patent Document 1 describes "anion exchangers with high performance in purifying organic solvents, and mixtures of such anion exchangers and cation exchangers," but does not describe specific organic solvent names or examples of how organic solvents were purified.

[0006] Patent Document 2 describes a liquid purification apparatus comprising a column filled with a porous adsorbent, a supply unit provided upstream of the column to supply liquid into the column, and a resin orifice provided downstream of the column to apply a pressure of a first predetermined value or higher to the liquid passing through the column. The method in Patent Document 2 applies pressure to the column by providing a resin orifice downstream of the column filled with a porous adsorbent, and is a technique that prevents the dissolved air from turning into gas when water and organic solvents mix, as the solubility of the gas changes.

[0007] Patent Document 3 describes a method for producing a purified alkali metal aqueous solution by contacting a crude alkali metal aqueous solution containing impurity metal components with a chelate resin and an ion exchange resin to remove the impurity metal components, wherein the chelate resin is a glucamine-type chelate resin and the ion exchange resin is an anion exchange resin. The method in Patent Document 3 is a purification method that combines a glucamine-type chelate resin and an anion exchange resin, but it does not describe the purification of organic solvents.

[0008] Patent Document 4 describes a method for treating a boron eluent containing alkali, in which a boron eluent containing alkali, regenerated from an ion exchange resin that has adsorbed boron, is passed through a cation exchange column packed with a strongly acidic cation exchange resin adjusted to the H type to recover high-purity boron-containing water. Patent Document 4 states that "in the process of purifying a boron eluent containing alkali, boric acid is B(OH) in the alkaline region." ４ － Because it exists in the solution as an anion, it is not adsorbed by cation exchange resin. Therefore, by passing the solution through an ion exchange column filled with a strongly acidic cation exchange resin adjusted to the H type, cations such as Na ions in the eluent are adsorbed and removed, while boron leaks out as is. Also, boric acid does not ionize in the acidic region. ３ BO ３The present invention was arrived at after confirming that the substance is dissolved as a molecule, is not adsorbed by ion exchange resin, and leaks out as is. Patent Document 4 states that boron is ionized in alkali and cannot be removed in acid, but the target solution is an alkaline solution, and there is no description regarding the purification of organic solvents.

[0009] Patent Document 5 describes a method for removing silica from saline solution containing silica ions, in which the saline solution is adjusted to a pH of 9 or higher, and then brought into contact with a selective silica ion adsorbent, wherein the selective silica ion adsorbent is a hydrated hydroxide-based adsorbent of a rare earth metal, or a strongly basic anion exchanger having a glucamine group. Patent Document 5 states that the glucamine group selectively adsorbs silica ions, but it does not describe the purification of silica in organic solvents.

[0010] Japanese Patent Publication No. 6165882, Japanese Unexamined Patent Publication No. 2022-043522, Japanese Unexamined Patent Publication No. 2014-188514, Japanese Patent Publication No. 3907937, Japanese Patent Publication No. 6369579

[0011] The object of the present invention is to provide a method for purifying organic solvents and an apparatus for purifying organic solvents that can reduce the amount of impurities such as metal impurities of as many types as possible from the organic solvent.

[0012] The present invention relates to a method for purifying an organic solvent, comprising an anion exchanger contact step of contacting the organic solvent to be purified with anion exchanger A and anion exchanger B, wherein anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and anion exchanger B is a chelate resin containing a glucamine-type ion exchanger.

[0013] In the anion exchanger contact step in the method for purifying the organic solvent, it is preferable to contact the organic solvent with a mixture of anion exchanger A and anion exchanger B, or to contact the organic solvent with anion exchanger A first, and then with anion exchanger B.

[0014] In the method for purifying an organic solvent, after the anion exchanger contact step, it is preferable to contact the organic solvent that has been brought into contact with the anion exchanger A and the anion exchanger B with at least one of an H-type cation exchanger and an H-type chelating ion exchanger.

[0015] In the method for purifying an organic solvent, it is preferable that the anion exchanger A and the anion exchanger B are anion exchange resins.

[0016] In the method for purifying an organic solvent, it is preferable that the organic solvent to be purified contains at least one selected from the group consisting of methanol, ethanol, isopropanol, N-methyl-2-pyrrolidone, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate.

[0017] In the method for purifying an organic solvent, it is preferable that the concentration of at least one impurity selected from the group consisting of boron, silicon, iron, and chromium in the organic solvent to be purified is 10 ppt or more.

[0018] The present invention relates to an apparatus for purifying an organic solvent, comprising anion exchanger contact means for bringing an organic solvent to be purified into contact with an anion exchanger A and an anion exchanger B, wherein the anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of an OH form, a free base form, a carbonate form, and a bicarbonate form, and the anion exchanger B is a chelating resin containing a glucamine-type ion exchange group.

[0019] In the apparatus for purifying an organic solvent, as the anion exchanger contact means, it is preferable to provide a container containing a mixture of the anion exchanger A and the anion exchanger B and bring the organic solvent into contact with the mixture of the anion exchanger A and the anion exchanger B, or, as the anion exchanger contact means, to provide a container containing the anion exchanger A and a container containing the anion exchanger B, and after bringing the organic solvent into contact with the anion exchanger A, bring it into contact with the anion exchanger B.

[0020] In the organic solvent purification apparatus, it is preferable to pressurize a container containing a mixture of the anion exchanger A and the anion exchanger B, or a container containing the anion exchanger A and a container containing the anion exchanger B to 0.05 MPa or more.

[0021] In the organic solvent purification apparatus, it is preferable to further include a cation exchanger contacting means for contacting the organic solvent contacted with the anion exchanger A and the anion exchanger B with at least one of an H-type cation exchanger and an H-type chelating ion exchanger.

[0022] According to the present invention, it is possible to provide an organic solvent purification method and an organic solvent purification apparatus capable of reducing the amount of impurities such as as many types of metal impurities as possible from an organic solvent.

[0023] It is a schematic configuration diagram showing an example of an organic solvent purification apparatus according to an embodiment of the present invention. It is a schematic configuration diagram showing another example of an organic solvent purification apparatus according to an embodiment of the present invention. It is a schematic configuration diagram showing another example of an organic solvent purification apparatus according to an embodiment of the present invention. It is a schematic configuration diagram showing another example of an organic solvent purification apparatus according to an embodiment of the present invention. It is a schematic configuration diagram showing another example of an organic solvent purification apparatus according to an embodiment of the present invention. It is a schematic configuration diagram showing another example of an organic solvent purification apparatus according to an embodiment of the present invention.

[0024] Embodiments of the present invention will be described below. This embodiment is an example of implementing the present invention, and the present invention is not limited to this embodiment.

[0025] An example of the schematic of an organic solvent purification apparatus according to an embodiment of the present invention is shown in FIG. 1, and its configuration will be described.

[0026] The organic solvent purification apparatus 1 shown in Figure 1 includes a container 10 containing a mixture of anion exchanger A and anion exchanger B, which serves as an anion exchanger contact means for bringing the organic solvent to be purified into contact with anion exchanger A and anion exchanger B. Anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and anion exchanger B is a chelate resin containing a glucamine-type ion exchange group.

[0027] In the purification apparatus 1, pipe 20 is connected to the inlet of container 10, and pipe 22 is connected to the outlet. A mixture of anion exchanger A and anion exchanger B is contained in container 10.

[0028] In the purification apparatus 1, the organic solvent to be purified is passed through the inlet of the container 10 via the piping 20, for example, in a downward or upward flow (upward flow in the example of Figure 1). Downward flow is preferred in the container 10 because it allows the liquid to pass through with minimal disturbance to the anion exchange layer. Even with an upward flow, purification performance can be maintained by filling the container so that there are no gaps and minimizing disturbance to the anion exchange layer, and by passing the liquid through at a flow rate that does not disturb the anion exchange layer. However, downward flow is particularly preferred because it allows for stable passage of the liquid with minimal disturbance to the anion exchange layer regardless of the flow rate. In the container 10, the amount of impurities in the organic solvent is reduced by bringing the organic solvent to contact a mixture of anion exchanger A and anion exchanger B (anion exchanger contact step). The purified organic solvent is discharged through the piping 22.

[0029] Figure 2 shows a schematic of another example of an organic solvent purification apparatus according to an embodiment of the present invention.

[0030] The organic solvent purification apparatus 2 shown in Figure 2 comprises an anion exchanger contact means for bringing the organic solvent to be purified into contact with anion exchanger A and anion exchanger B, a container 12 containing anion exchanger A, and a container 14 containing anion exchanger B. Anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and anion exchanger B is a chelate resin containing a glucamine-type ion exchange group.

[0031] In the purification apparatus 2, a pipe 24 is connected to the inlet of container 12, a pipe 26 connects the outlet of container 12 to the inlet of container 14, and a pipe 28 is connected to the outlet of container 14. Anion exchanger A is contained in container 12, and anion exchanger B is contained in container 14.

[0032] In the purification apparatus 2, the organic solvent to be purified is passed through piping 24 from the inlet of container 12, for example, in a downward or upward flow (upward flow in the example of Figure 2), and through piping 26 from the inlet of container 14, for example, in a downward or upward flow (upward flow in the example of Figure 2). The direction of flow in containers 12 and 14 is preferably downward flow because it allows the liquid to pass through with minimal disturbance to the anion exchange layer. Even with an upward flow, purification performance can be maintained by filling the containers so that there are no gaps and minimizing disturbance to the anion exchange layer, and by passing the liquid through at a flow rate that does not disturb the anion exchange layer. However, a downward flow is particularly preferred because it allows for stable passage of the liquid through with minimal disturbance to the anion exchange layer, regardless of the flow rate. In one of containers 12 and 14, the liquid may pass through in a downward flow, and in the other, in an upward flow. In container 12, the organic solvent to be treated is brought into contact with anion exchanger A, and then in container 14, the organic solvent to be treated is brought into contact with anion exchanger B, thereby reducing the amount of impurities in the organic solvent (anion exchanger contact step). The purified organic solvent is discharged through piping 28.

[0033] The inventors have found that by purifying an organic solvent to be purified by contacting it with an anion exchanger A having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and an anion exchanger B containing a glucamine-type ion exchange group, the amount of impurities such as metal impurities of as many types as possible can be reduced from the organic solvent. By contacting an organic solvent with an anion exchanger having at least one ionic form selected from the group consisting of low basicity OH form, free base form, carbonate form, and bicarbonate form, and a chelate resin containing a glucamine-type ion exchange group, a purified organic solvent can be obtained with a particularly reduced amount of metal impurities, including boron.

[0034] To enhance the boron reduction performance of chelate resins containing glucamine-type ion exchange groups, which are boron-selective ion exchangers, the boron content can be further reduced by purifying organic solvents containing boron-containing metal impurities using a double-bed or mixed-bed ion exchanger with an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form. This method is a purification method that utilizes the ionization of boron compounds in alkali, as will be described later.

[0035] The organic solvent to be purified contains impurities. These impurities include cationic impurities and metallic impurities such as anionic impurities. Examples of metallic impurities include Na, K, Li, Mg, Ca, Ti, Al, V, Cr, Fe, Co, Mn, Ni, Cu, Zn, Sr, Mo, Ag, Cd, Sn, Sb, Ba, W, Pt, As, Pb, Cl, B, and Si. The content of these impurities in the organic solvent to be purified is, for example, in the range of 10 ppt to 100 ppb, preferably 10 ppt to 20 ppb. According to the organic solvent purification method and apparatus of this embodiment, the amount of these metallic impurities can be reduced to, for example, less than 10 ppt. That is, the purified organic solvent obtained by the organic solvent purification method and apparatus of this embodiment is an organic solvent in which the amount of these metallic impurities is, for example, less than 10 ppt.

[0036] Among anionic impurities, boron, silicon, iron, and chromium are all elements that can exist in anionic form as oxides. Therefore, these anionic impurities are difficult to reduce with functional materials (cation exchange resins, cation exchange membranes) that have general cation exchange groups that exchange ions with cationic impurities. In contrast, the method and apparatus for purifying organic solvents according to this embodiment can reduce the amount of metallic impurities such as boron, silicon, iron, and chromium in the organic solvent.

[0037] The organic solvent to be purified has a concentration of at least one impurity selected from the group consisting of boron, silicon, iron, and chromium, for example, 10 ppt or more. According to the organic solvent purification method and apparatus of this embodiment, for an organic solvent in which the concentration of at least one of boron, silicon, iron, and chromium is 10 ppt or more, the amount thereof, or the amounts thereof, can be reduced to less than 1 ppt by suppressing contamination during the purification operation.

[0038] When reducing the amount of boron in organic solvents, OH-type, carbonate-type, and bicarbonate-type strongly basic anion exchange resins can be used. However, chelate resins containing glucamine-type ion exchange groups specifically reduce boron, so using them in combination can further reduce the amount of boron.

[0039] Regarding anion exchanger B, examples of glucamine-type ion exchange groups include N-alkyl-glucamine groups (where alkyl is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms), and N-methyl-glucamine groups are preferred from the standpoint of availability.

[0040] The matrix of the chelate resin containing glucamine-type ion exchange groups may be macroporous or gel-type. The particle size of the chelate resin containing glucamine-type ion exchange groups is, for example, in the range of 200 to 1000 μm, and preferably in the range of 300 μm to 700 μm.

[0041] The operating temperature of the chelate resin containing a glucamine-type ion exchange group is, for example, in the range of 10 to 60°C, and preferably in the range of 15 to 50°C.

[0042] Specific product names of chelating resins containing glucamine-type ion exchange groups include, for example, AMBERLITE (registered trademark) IRA743 (manufactured by Organo Corporation), ORLITE (registered trademark) X-U653J (manufactured by Organo Corporation), AMBERTEC (registered trademark) UP7530 (manufactured by DuPont), DIAION (registered trademark) CRB03 (manufactured by Mitsubishi Chemical Corporation), DIAION (registered trademark) CRB05 (manufactured by Mitsubishi Chemical Corporation), MUROMAC (registered trademark) XMS-5119-FB (manufactured by Muromachi Chemical Co., Ltd.), MUROMAC (registered trademark) XMS-515B-FB (manufactured by Muromachi Chemical Co., Ltd.), MUROMAC (registered trademark) XMS-519B-FB (manufactured by Muromachi Chemical Co., Ltd.), and the like.

[0043] As described in Patent Document 4, since boron compounds do not have ionic properties in the acidic range, it is difficult to reduce them by ion exchange. However, in the alkaline region, B(OH) ４ －Since it exists in solution as an anion, its reduction can be achieved by ion exchange. In the purification method and apparatus according to this embodiment, a technique to enhance boron reduction by ionizing the boron compound under alkaline conditions is applied to the organic solvent. After contacting the compound with an anion exchanger A having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, the compound is then contacted with an anion exchanger B, which is a chelate resin containing a glucamine-type ion exchange group, or with a mixed bed of anion exchanger A and anion exchanger B. This allows the inside of the container 14 containing anion exchanger B, or the inside of the container 10 containing a mixed bed of anion exchanger A and anion exchanger B, to be adjusted to be more alkaline, thereby adjusting the pH to the optimal level for boron reduction. A mixed bed of anion exchanger A and anion exchanger B is more efficient and preferable than a double bed in which anion exchanger A is contacted first, and then anion exchanger B is contacted, because it can adjust the inside of the container containing the chelate resin containing glucamine-type ion exchange groups to a weakly alkaline to alkaline (e.g., pH 7.5 or higher) which is optimal for boron reduction. Alternatively, the resin may be treated by contacting it with anion exchanger B, which is a chelate resin containing glucamine-type ion exchange groups, and then contacted with anion exchanger A having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form. Anion exchanger B itself is also an anion exchanger, and Cl － OH － Because of the release of boron compounds, a slight change in pH causes ionization of the boron compounds, which can be reduced by ion exchange. However, it is thought that contacting the mixture with anion exchanger A first allows for a greater reduction of boron compounds by ion exchange compared to contacting it with anion exchanger B first.

[0044] Anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and is particularly preferred to be at least one anion exchanger selected from a weakly basic anion exchanger having one or more primary to tertiary amines, or an anion exchanger having a quaternary amine. All of these anion exchangers release alkaline components during ion exchange, and can contribute to the presence of boron in the container housing the ion exchanger as borate ions. In the purification of hydrolyzable organic solvents, it is preferable to use a weakly basic anion exchanger selected from the carbonate form and bicarbonate form because hydrolysis of the organic solvent is less likely to occur, but in the purification of other organic solvents, either a weakly basic anion exchanger or a strongly basic anion exchanger may be used.

[0045] Specific trade names for anion exchangers having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form include, for example, ORLITE® A-P5200 HCO3 (manufactured by Organo Corporation) and AMBERTEC® UPC7 HCO3 (manufactured by DuPont).

[0046] The matrix of anion exchanger A may be either macroporous or gel-type. The particle size of anion exchanger A is, for example, in the range of 200 to 1000 μm, and preferably in the range of 300 μm to 700 μm.

[0047] Although it has been confirmed that a single bed of anion exchanger A can reduce the amount of cationic impurities of a certain type (see the Examples section), if the alkalinity is too high, the anion exchanger may be altered by the organic solvent. For this reason, an ionic form of anion exchanger A with a lower basicity is preferred over the OH-type strongly basic anion exchanger, which has the highest basicity.

[0048] When an anion exchanger selected from carbonate and bicarbonate forms releases carbonate ions and bicarbonate ions by ion exchange, or when carbonate ions are dissolved in an organic solvent, protons (H) are introduced into the system. ＋ When large amounts of ) are present, carbon dioxide (CO2)２ ) Gas may be generated. If the container containing the ion exchanger is filled with bubbles, it is undesirable because the organic solvent to be treated cannot be sufficiently brought into contact with the ion exchanger. Chelate resins containing glucamine-type ion exchange groups are anion exchangers, so protons (H) are released by ion exchange. ＋ It does not release ions. Therefore, chelate resins containing glucamine-type ion exchange groups can be suitably used in combination with anion exchangers selected from carbonate-type and bicarbonate-type anion exchangers.

[0049] Anion exchanger A and anion exchanger B are preferably anion exchange resins, for ease of filling into the same container, and are, for example, resins having ion exchange groups on a substrate such as a styrene-divinylbenzene copolymer or a vinylbenzyl chloride-divinylbenzene copolymer. The anion exchanger can be selected in the form of a filter or block. Alternatively, anion exchanger in the form of a filter or block may be combined with an anion exchange resin.

[0050] The amounts used for anion exchanger A, selected from carbonate and bicarbonate forms, and anion exchanger B, which is a chelate resin containing a glucamine-type ion exchange group, can be selected according to, for example, the amount of boron and other impurities present in the organic solvent to be treated. The mixing ratio of anion exchanger B to anion exchanger A may be, for example, in the range of 0.1 to 100 volume percent.

[0051] To reduce the amount of cationic impurities, such as alkali metals, that elute from anion exchanger A and anion exchanger B, or that are difficult to reduce by anion exchanger A and anion exchanger B alone, after the anion exchanger contact step, the organic solvent that has been in contact with anion exchanger A and anion exchanger B may be brought into contact with at least one of an H-type cation exchanger and an H-type chelate ion exchanger. A schematic example of a purification apparatus with such a configuration is shown in Figures 3 and 4. Anion exchanger A and anion exchanger B, and at least one of an H-type cation exchanger and an H-type chelate ion exchanger may be packed in the same container to form a mixed bed. When packed in the same container, it is preferable that the ion exchange capacity of the H-type cation exchanger is less than that of anion exchanger A in order to maintain the pH inside the container at a weakly alkaline to alkaline level.

[0052] The purification apparatus 3 shown in Figure 3 further includes a container 16 located downstream of the container 10, which contains at least one of the H-type cation exchanger and the H-type chelate ion exchanger, as a cation exchanger contact means for contacting the organic solvent, after contact with anion exchanger A and anion exchanger B, with at least one of the H-type cation exchanger and the H-type chelate ion exchanger.

[0053] In the purification apparatus 3, the outlet of container 10 and the inlet of container 16 are connected by piping 22. Piping 30 is connected to the outlet of container 16.

[0054] In the purification apparatus 3, the organic solvent to be purified is passed through the inlet of the container 10 via the piping 20, for example, in a downward or upward flow (upward flow in the example of Figure 3). In the container 10, the amount of impurities in the organic solvent is reduced by bringing the organic solvent to contact anion exchanger A and anion exchanger B (anion exchanger contact step). The organic solvent is then passed through the inlet of the container 16 via the piping 22, for example, in a downward or upward flow (upward flow in the example of Figure 3). In the container 16, the amount of impurities in the organic solvent is further reduced by bringing the organic solvent, after contact with anion exchanger A and anion exchanger B, into contact with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger (cation exchanger contact step). The purified organic solvent is discharged through the piping 30.

[0055] The purification apparatus 4 shown in Figure 4 further includes a container 16 located downstream of the container 14, which contains at least one of the H-type cation exchanger and the H-type chelate ion exchanger, as a cation exchanger contact means for contacting the organic solvent, after contact with anion exchanger A and anion exchanger B, with at least one of the H-type cation exchanger and the H-type chelate ion exchanger.

[0056] In the purification apparatus 4, the outlet of container 14 and the inlet of container 16 are connected by piping 28. Piping 30 is connected to the outlet of container 16.

[0057] In the purification apparatus 4, the organic solvent to be purified is passed through piping 24 from the inlet of container 12 in a downward or upward flow (upward flow in the example of Figure 4), and through piping 26 from the inlet of container 14 in a downward or upward flow (upward flow in the example of Figure 4). The amount of impurities in the organic solvent is reduced by contacting the organic solvent to be processed with anion exchanger A in container 12 and with anion exchanger B in container 14 (anion exchanger contact step). The organic solvent is passed through piping 28 from the inlet of container 16 in a downward or upward flow (upward flow in the example of Figure 4). In container 16, the amount of impurities in the organic solvent is further reduced by contacting the organic solvent, after contact with anion exchanger A and anion exchanger B, with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger (cation exchanger contact step). The purified organic solvent is discharged through piping 30.

[0058] After the anion exchanger contact step, the amount of impurities can be reduced further by contacting the organic solvent that has been in contact with anion exchanger A and anion exchanger B with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger.

[0059] The H-type cation exchanger may be either a strongly acidic cation exchanger or a weakly acidic cation exchanger.

[0060] Specific product names for H-type cation exchangers include, for example, Orlite® DS-1, DS-4, Amberlite® IRC76, Diaion® SK104H, Diaion® PK208L, Diaion® UBK04, Diaion® WK10, Diaion® WK10S, and 3M® Metal Ion Removal Filter MIP Series SCP Series.

[0061] Specific product names for H-type chelate ion exchangers include, for example, Orlite® DS-21, DS-22, Diaion® CR11, Diaion® CR20, and 3M® metal ion removal filters MIP series and APP series.

[0062] The cation exchange matrix may be macroporous or gel-type. The particle size of the cation exchange matrix is, for example, in the range of 200 to 1000 μm, and preferably in the range of 300 μm to 700 μm.

[0063] The cation exchange material is preferably a cation exchange resin, due to its ease of filling into the same container, for example, a resin having ion exchange groups on a substrate such as a styrene-divinylbenzene copolymer or a vinylbenzyl chloride-divinylbenzene copolymer.

[0064] Impurities are reduced by bringing the organic solvent to be treated into contact with the ion exchanger at least once. That is, it may be a single pass in which the organic solvent to be treated and the ion exchanger come into contact once, or the organic solvent may be circulated and brought into contact with the organic solvent to be treated and the ion exchanger at least twice.

[0065] When circulating organic solvents, the purified organic solvent should be circulated towards the inlet side of container 10. A schematic example of such a purification apparatus is shown in Figure 5. In the organic solvent purification apparatus 5 shown in Figure 5, a circulation pipe 32 branched from pipe 22 is connected to pipe 20.

[0066] In the purification apparatus 5, the organic solvent to be purified is passed through the inlet of the container 10 through the piping 20, for example, in a downward or upward flow (upward flow in the example of Figure 5). In the container 10, the amount of impurities in the organic solvent is reduced by bringing the organic solvent to contact anion exchanger A and anion exchanger B (anion exchanger contact step). The purified organic solvent is discharged through the piping 22. At least a portion of the purified organic solvent is circulated through the circulation piping 32 (circulation step), and passed back into the container 10 through the piping 20, where it comes into contact with anion exchanger A and anion exchanger B again (anion exchanger contact step). This further reduces the amount of impurities in the organic solvent.

[0067] In the configuration of the purification apparatus 2 shown in Figure 2, similar to the purification apparatus 5, a circulation pipe branched from pipe 26 or pipe 28 may be connected to pipe 24 to circulate the purified organic solvent to the inlet side of container 12.

[0068] A filtration means, such as a microfiltration membrane or a particulate filter combining a microfiltration membrane with other functional materials, may be installed downstream of the ion exchanger to reduce the amount of particulate matter and other particles contained in the purified organic solvent after it has passed through. A schematic example of such a purification apparatus is shown in Figure 6.

[0069] The purification apparatus 6 shown in Figure 6 further includes a filtration device 34 downstream of the container 10 as a filtration means for filtering the purified organic solvent after contact with anion exchanger A and anion exchanger B.

[0070] In the purification apparatus 6, the outlet of the container 10 and the inlet of the filtration device 34 are connected by piping 22. Piping 36 is connected to the outlet of the filtration device 34.

[0071] In the purification apparatus 6, the organic solvent to be purified is passed through the inlet of the container 10 through the piping 20, for example, in a downward or upward flow (upward flow in the example of Figure 6). In the container 10, the amount of impurities in the organic solvent is reduced by bringing the organic solvent to contact anion exchanger A and anion exchanger B (anion exchanger contact step). The purified organic solvent is sent to the filtration apparatus 34 through the piping 22. In the filtration apparatus 34, the purified organic solvent after contact with anion exchanger A and anion exchanger B is passed through, for example, a microfiltration membrane or a particulate filter combining a microfiltration membrane and other functional materials, to reduce the amount of particulate matter and other particles contained in the purified organic solvent (filtration step). The filtered liquid is discharged through the piping 36. This further reduces the amount of impurities in the purified organic solvent.

[0072] In the configuration of the purification apparatus 2 shown in Figure 2, similar to the purification apparatus 6, a filtration means such as a microfiltration membrane or a microfiltration membrane combined with other functional materials for removing particulate matter may be installed downstream of the ion exchanger to reduce the amount of particulate matter and other particles contained in the purified organic solvent after it has passed through.

[0073] The filtration device 22 is not particularly limited as long as it can reduce the amount of fine particles (for example, particle size of about 1 to 200 nm) contained in the purified organic solvent, but examples include a microfiltration membrane or a fine particle removal filter that combines a microfiltration membrane with other functional materials.

[0074] For example, the liquid flow conditions in the purification apparatus 1 to 6 can be maintained within a range of 15 to 50°C. An ion exchange material such as an ion exchange resin may be placed in a container for storing particles, such as a column, and packed with an organic solvent to bring it into contact with the material by passing it through in an upward flow from top to bottom or a downward flow from bottom to top. Alternatively, the organic solvent may be directly added to the container containing the ion exchange material such as an ion exchange resin and brought into contact by stirring for a predetermined time.

[0075] Contact by liquid flow results in a space velocity (SV) relative to the entire resin tower, for example, 0.5 to 100 (h). －１ The range should be 1 to 50 (h －１The range is preferably 2 to 30 (h －１ A range of ) is more preferable. When using a strongly basic anion exchange resin, the space velocity (SV) relative to the container containing the strongly basic anion exchange resin should be, for example, 1 to 200 (h －１ The range should be 2 to 100 (h －１ The range is preferably 4 to 60 (h －１ The range of ) is more preferable.

[0076] The container for housing the ion exchanger is, for example, a cylindrical or other tubular sealed container made of a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene (PFA), polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), etc., having a liquid inlet and a liquid outlet, or it may be a cartridge that can be attached to and detached from the main body of an ion exchange device.

[0077] In the purification apparatus 1 to 6, methods for delivering the organic solvent to the container include pumping or pressurized delivery.

[0078] It is preferable to pressurize the containers containing the ion exchangers for purifying the organic solvent, i.e., container 10 containing a mixture of anion exchanger A and anion exchanger B, or container 12 containing anion exchanger A and container 14 containing anion exchanger B. By pressurizing these containers, the carbonate ions generated are less likely to gasify, they dissolve more easily in the organic solvent, and the generation of carbon dioxide can be suppressed. It is preferable to pressurize these containers to, for example, 0.05 MPa or higher. The upper limit of the pressurization can be, for example, 0.3 MPa or less. As for the pressurization method, it is preferable to use a method that minimizes metal contamination. This can be done by adjusting the flow path at the outlet of the container containing the ion exchangers to be smaller than the inlet, or by using other pressurization methods. Here, an example of the method of "adjusting the flow path at the outlet of the container containing the ion exchangers to be smaller than the inlet" is to design the piping that becomes the flow path at the outlet of the container to be smaller than the piping that becomes the flow path at the inlet when designing the purification apparatus. Other pressurization methods include, for example, installing a functional material, such as a filter with fine pores, that applies pressure to the container containing the ion exchanger, downstream of the container containing the ion exchanger. A combination of the filter and the other functional materials mentioned above may also be used.

[0079] The purification method and apparatus according to this embodiment target the purification of organic solvents, including alcoholic solvents, ketone solvents, ether solvents, and ester solvents. There are no particular restrictions on the organic solvent, but examples include organic solvents containing at least one of the following: alcoholic solvents such as methanol, ethanol, and isopropanol (IPA); ether solvents such as 1-methoxy-2-propanol (propylene glycol monomethyl ether) (PGME), propylene glycol monomethyl ether acetate (PGMEA), and tetrahydrofuran (THF); ketone solvents such as cyclohexanone, acetone, and 2-butanone; ester solvents such as ethyl lactate and n-butyl acetate; sulfoxide solvents such as dimethyl sulfoxide (DMSO); lactone solvents such as γ-butyl lactone; lactam solvents such as N-methyl-2-pyrrolidone (NMP); aromatic solvents such as toluene and xylene; and phenolic solvents such as phenol. Of these, the organic solvent to be purified preferably contains at least one selected from the group consisting of methanol, ethanol, isopropanol, N-methyl-2-pyrrolidone, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate.

[0080] Alcoholic solvents such as methanol, ethanol, and isopropanol are relatively stable, and purification using strongly basic anion exchange resins (especially the OH form) is commonly performed. Ketone solvents, ether solvents, and ester solvents such as N-methyl-2-pyrrolidone and similar five-membered ring organic compounds (e.g., N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc.), 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate may decompose with strongly basic anion exchange resins of the OH form. Therefore, it is preferable to use strongly basic anion exchange resins of the carbonate or bicarbonate form with low basicity, or weakly basic anion exchange resins of the free base, carbonate, or bicarbonate form.

[0081] This specification includes the following embodiments: (1) A method for purifying an organic solvent, comprising an anion exchanger contact step of contacting the organic solvent to be purified with anion exchanger A and anion exchanger B, wherein anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and anion exchanger B is a chelate resin containing a glucamine-type ion exchanger.

[0082] (2) A method for purifying an organic solvent as described in (1), wherein in the anion exchanger contact step, the organic solvent is brought into contact with a mixture of the anion exchanger A and the anion exchanger B, or the organic solvent is brought into contact with the anion exchanger A and then with the anion exchanger B.

[0083] (3) A method for purifying an organic solvent according to (1) or (2), wherein, after the anion exchanger contact step, the organic solvent that has been in contact with the anion exchanger A and the anion exchanger B is brought into contact with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger.

[0084] (4) A method for purifying an organic solvent according to any one of (1) to (3), wherein the anion exchanger A and the anion exchanger B are an anion exchange resin.

[0085] (5) A method for purifying an organic solvent according to any one of (1) to (4), wherein the organic solvent to be purified comprises at least one selected from the group consisting of methanol, ethanol, isopropanol, N-methyl-2-pyrrolidone, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate.

[0086] (6) A method for purifying an organic solvent according to any one of (1) to (5), wherein the organic solvent to be purified has a concentration of at least one impurity selected from the group consisting of boron, silicon, iron, and chromium of 10 ppt or more.

[0087] (7) A method for purifying an organic solvent according to any one of (1) to (6), characterized in that a container containing a mixture of the anion exchanger A and the anion exchanger B, or a container containing the anion exchanger A and a container containing the anion exchanger B are pressurized to 0.05 MPa or higher.

[0088] (8) An organic solvent purification apparatus comprising an anion exchanger contact means for bringing the organic solvent to be purified into contact with anion exchanger A and anion exchanger B, wherein the anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and the anion exchanger B is a chelate resin containing a glucamine-type ion exchanger.

[0089] (9) An organic solvent purification apparatus according to (8), wherein the anion exchanger contact means comprises a container containing a mixture of anion exchanger A and anion exchanger B, and the organic solvent is brought into contact with the mixture of anion exchanger A and anion exchanger B, or the anion exchanger contact means comprises a container containing anion exchanger A and a container containing anion exchanger B, and the organic solvent is brought into contact with anion exchanger A and then with anion exchanger B.

[0090] A purification apparatus for organic solvents as described in (10)(9), wherein the container containing the mixture of anion exchanger A and anion exchanger B, or the container containing anion exchanger A and the container containing anion exchanger B, are pressurized to 0.05 MPa or higher.

[0091] A purifying apparatus for organic solvents according to any one of (11)(8) to (10), further comprising a cation exchanger contact means for contacting the organic solvent that has been in contact with the anion exchanger A and the anion exchanger B with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger.

[0092] A purification apparatus for organic solvents according to any one of (12)(8) to (11), wherein the anion exchanger A and the anion exchanger B are anion exchange resins.

[0093] A device for purifying organic solvents according to any one of (13)(8) to (12), wherein the organic solvent to be purified comprises at least one selected from the group consisting of methanol, ethanol, isopropanol, N-methyl-2-pyrrolidone, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate.

[0094] A device for purifying organic solvents according to any one of (14)(8) to (13), wherein the organic solvent to be purified has a concentration of 10 ppt or more of at least one impurity selected from the group consisting of boron, silicon, iron, and chromium.

[0095] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0096] <Test 1> As Test 1, propylene glycol monomethyl ether acetate (PGMEA) was converted to a bicarbonate form (HCO3). ３ (Formula) Metal removal was performed using an anion exchange resin (anion exchanger A-1).

[0097] <Test 2> In Test 2, isopropanol (IPA) was converted to bicarbonate form (HCO2). ３ Form) Anion exchange resin (anion exchanger A-1) alone, and bicarbonate type (HCO3) ３Metal removal was performed using a combination of anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B).

[0098] <Test 3> In Test 3, PGMEA was used to select a chelate resin containing an N-methylglucamine group (anion exchanger B) alone, and a bicarbonate form (HCO3). ３ Boron removal was performed using a combination of an anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B).

[0099] [Experimental Method] Anion exchanger A-1: ​​ORLITE (registered trademark) A-P5200 HCO3 (ionic form: HCO3) ３ Form, functional group: quaternary amine), resin volume: 25 mL Anion exchanger B: ORLITE (registered trademark) X-U653J (ionic form: free base (FB (FreeBase)) form, functional group: N-methylglucamine group), resin volume: 25 mL Mixture: The above anion exchanger A-1 and the above anion exchanger B are mixed in a volume ratio of 1:1 Column: Fluororesin (perfluoroalkoxyalkane (PFA)) column, outer diameter 19 mm, height 300 mm Fluid flow rate SV (space velocity) 5 (h －１ ) Back pressure: Pressurized to 0.05-0.1 MPa inside the ion exchange resin column via an orifice placed downstream of the column Stock solution: PM thinner (TOK Corporation), IPA SE grade (Tokuyama Corporation) PGMEA simulation solution: Prepared by adding ICP-MS standard solution (SPEX Corporation) to the stock solution PM thinner so that the concentration of each metal element is 100 ppt. Metal analysis: ICP-MS (Agilent 8900) is used.

[0100] Test Procedure: (PGMEA Purification) [1] A PGMEA simulated solution was prepared as described above. [2] The PGMEA simulated solution was passed through each resin in an amount 20 times the volume of the resin. [3] After [2], a sample for metal analysis was taken and metal analysis was performed.

[0101] (IPA purification) [1] IPA SE grade was passed through the resin in an amount 20 times the volume of the resin. [2] After [1], a sample for metal analysis was taken and metal analysis was performed.

[0102] [Results] The results of Test 1 are shown in Table 1, the results of Test 2 are shown in Table 2, and the results of Test 3 are shown in Table 3.

[0103]

[0104] Based on the results of Test 1, HCO ３ By using a single bed of type anion exchange resin (anion exchanger A-1), it was possible to reduce both cationic impurities, mainly alkaline earth metals, and anionic impurities, such as Fe and As, which are thought to exist as anionic oxides, from PGMEA. Both cationic and anionic forms of metal impurities were reduced by HCO3 ３ This could be reduced using anion exchange resin.

[0105]

[0106] Based on the results of Test 2, HCO ３ Anion exchange resin (anion exchanger A-1) single bed, HCO ３ By using a mixed bed of an anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B) (A-1) + B, both cationic and anionic metal impurities were reduced from IPA. Although IPA and PGMEA are organic solvents with significantly different polarities, they showed similar effects. In particular, HCO3 ３ An unexpected effect was obtained by combining a type anion exchange resin (anion exchanger A-1) with a chelate resin containing an N-methylglucamine group (anion exchanger B), which reduced the amount of cationic impurities.

[0107]

[0108] The results of Test 3 showed that both the single bed and the (A-1) + B mixed bed of the chelate resin containing an N-methylglucamine group (anion exchanger B) were able to reduce the amount of boron impurities from PGMEA. In particular, anion exchanger B has an N-methylglucamine group and is a chelate resin that selectively removes boron, but HCO ３The boron reduction performance was improved by mixing it with a type anion exchange resin (anion exchanger A-1). This is thought to be because mixing them adjusts the pH inside the resin column to a slightly alkaline pH, which is suitable for boron reduction. In other words, compared to using a single bed of chelate resin containing an N-methylglucamine group (anion exchanger B), HCO3 ３ It was found that it is preferable to combine it with an anion exchange resin (anion exchanger A-1).

[0109] This effect is achieved by first removing the organic solvent from HCO3. ３ This can also be achieved by contacting a shaped anion exchange resin (anion exchanger A-1) with a chelate resin containing an N-methylglucamine group (anion exchanger B). ３ The liquid treated with the anion exchange resin (anion exchanger A-1) is converted to bicarbonate ions (HCO3) through ion exchange. ３ － Since the release of ) results in a weakly alkaline state, it is thought that the treatment solution can be adjusted to an appropriate pH for anion exchanger B.

[0110] <Test 4> In Test 4, boron removal was performed using a chelate resin containing an N-methylglucamine group (anion exchanger B) alone, and in combination with a free basic form weak anion exchange resin (anion exchanger A-2) and a chelate resin containing an N-methylglucamine group (anion exchanger B). The results of Test 4 are shown in Table 4.

[0111] [Experimental Method] Anion exchanger A-2: ORLITE® DS-6 (ionic form: free base form, functional group: tertiary amine), resin volume: 25 mL Anion exchanger B: ORLITE® X-U653J (ionic form: free base form, functional group: N-methylglucamine group), resin volume: 25 mL Mixture: Anion exchanger A-2 and anion exchanger B are mixed in a volume ratio of 1:1 Column: Fluoropolymer (PFA) column, outer diameter 19 mm, height 300 mm Fluid flow rate: SV5 (h －１) Back pressure: Pressurized to 0.05-0.1 MPa inside the ion exchange resin column via an orifice placed downstream of the column Stock solution: Tokuso IPA (manufactured by Tokuyama) IPA simulant solution: Prepared by adding ICP-MS standard solution (manufactured by SPEX) to the stock IPA so that the boron concentration is 20 ppb Metal analysis: ICP-MS (Agilent 8900) is used

[0112] Test Procedure: (IPA Purification) [1] An IPA simulant solution was prepared as described above. [2] The IPA simulant solution was passed through each resin in an amount 20 times the volume of the resin. [3] After [2], a sample for metal analysis was taken and metal analysis was performed.

[0113]

[0114] The results of Test 4 showed that both a single bed of chelate resin containing N-methylglucamine groups (anion exchanger B) and a mixed bed of chelate resin containing N-methylglucamine groups (anion exchanger B) and free basic form weak anion exchange resin (anion exchanger A-2) were able to reduce the amount of boron impurities in the IPA. In particular, the (A-2) + B mixed bed significantly reduced the boron concentration in the stock solution from approximately 22 ppb to 50 ppt or less, showing a remarkable effect. On the other hand, while the B single bed was also able to significantly reduce the boron concentration, it did not show the same effect as the (A-2) + B mixed bed.

[0115] Similar to Test 3, it is believed that the pH inside the resin column was adjusted to a weakly alkaline pH, which is suitable for boron reduction, by using a mixed bed of chelate resin containing N-methylglucamine groups (anion exchanger B) and free basic weak anion exchange resin (anion exchanger A-2). In other words, it was found that combining it with free basic weak anion exchange resin (anion exchanger A-2) is preferable to using chelate resin containing N-methylglucamine groups (anion exchanger B) as a single bed.

[0116] This effect can also be achieved by first contacting the organic solvent with a free basic weak anion exchange resin (anion exchanger A-2), and then contacting it with a chelate resin containing an N-methylglucamine group (anion exchanger B). The solution treated with the free basic weak anion exchange resin (anion exchanger A-2) is converted to hydroxyl ions (OH) by ion exchange. － Since the release of ) results in a weakly alkaline state, it is thought that the treatment solution can be adjusted to an appropriate pH for anion exchanger B.

[0117] <Test 5> In Test 5, metals other than boron were removed using a chelate resin containing an N-methylglucamine group (anion exchanger B) alone, and a combination of a free basic weak anion exchange resin (anion exchanger A-2) and a chelate resin containing an N-methylglucamine group (anion exchanger B). The results of Test 5 are shown in Tables 5 and 6.

[0118] [Experimental Method] Anion exchanger A-2: ORLITE® DS-6 (ionic form: free base (FB) form, functional group: tertiary amine), resin volume: 25 mL Anion exchanger B: ORLITE® X-U653J (ionic form: free base form, functional group: N-methylglucamine group), resin volume: 25 mL Mixture: Anion exchanger A-2 and anion exchanger B are mixed in a volume ratio of 1:1 Column: Fluoropolymer (PFA) column, outer diameter 19 mm, height 300 mm Fluid flow rate: SV5 (h －１ ), SV30 (h －１ ) Back pressure: Pressurized to 0.05-0.1 MPa inside the ion exchange resin column via an orifice placed downstream of the column Stock solution: PM thinner (TOK Corporation), IPA SE grade (Tokuyama Corporation) PGMEA simulated solution: Prepared by adding ICP-MS standard solution (SPEX Corporation) to the stock PM thinner so that the concentration of each metal element is 100 ppt IPA simulated solution: Prepared by adding ICP-MS standard solution (SPEX Corporation) to the stock IPA so that the concentration of each metal element is 100 ppt Metal analysis: ICP-MS (Agilent 8900) is used

[0119] Test Procedure: (PGMEA Purification) [1] A PGMEA simulated solution was prepared as described above. [2] The PGMEA simulated solution was passed through each resin in an amount 20 times the volume of the resin. [3] After [2], a sample for metal analysis was taken and metal analysis was performed.

[0120] (IPA purification) [1] An IPA simulant solution was prepared as described above. [2] The IPA simulant solution was passed through each resin in an amount 20 times the volume of the resin. [3] After [2], samples for metal analysis were taken and metal analysis was performed.

[0121]

[0122]

[0123] Evaluation of the PGMEA simulated solution showed that combining a chelate resin containing an N-methylglucamine group (anion exchanger B) with a free basic weak anion exchange resin (anion exchanger A-2) improved the reduction performance of Al and Cr. In particular, when the flow rate was SV5 (h －１ ) to SV30 (h －１ Even when increased to these levels, these combinations maintained their metal reduction performance. Al is an amphoteric metal, and Cr is a metal that can exist as an anion in the form of an oxide. In addition to boron, cationic alkali metals such as Na were also reduced to 10 ppt or less with little influence from SV.

[0124] While sodium (Na) could hardly be reduced in the IPA simulation solution, boron, al, and cr were similarly reduced. In particular, the mixed bed of chelate resin containing N-methylglucamine groups (anion exchanger B) and free basic form weak anion exchange resin (anion exchanger A-2) showed higher boron reduction performance than the single bed of chelate resin containing N-methylglucamine groups (anion exchanger B).

[0125] <Test 6> In Test 6, treatment was performed using a combination of a free basic weak anion exchange resin (anion exchanger A-2) and a chelate resin containing an N-methylglucamine group (anion exchanger B), followed by metal removal using an H-type chelate ion exchanger (cation exchanger). The results of Test 6 are shown in Table 7.

[0126] [Experimental Method] Anion exchanger A-2: ORLITE® DS-6 (ionic form: free base form, functional group: tertiary amine), resin volume: 12.5 mL Anion exchanger B: ORLITE® X-U653J (ionic form: free base form, functional group: N-methylglucamine group), resin volume: 12.5 mL Cation exchanger: ORLITE® DS-21 (ionic form: H form, functional group: chelate), resin volume: 25 mL Mixture: Anion exchanger A-2 and anion exchanger B are mixed in a volume ratio of 1:1 Column: Fluoropolymer (PFA) column, outer diameter 19 mm, height 300 mm x 2 columns Liquid is passed through in the order of Column 1 (mixture of anion exchanger A-2 + anion exchanger B) → Column 2 (cation exchanger) Liquid flow rate: SV10 (h －１ ) Back pressure: Pressurized to 0.05-0.1 MPa inside the ion exchange resin column via an orifice placed downstream of the column Stock solution: Tokuyama IPA SE grade (manufactured by Tokuyama) PGMEA simulated solution: Prepared by adding ICP-MS standard solution (manufactured by SPEX) to the stock solution PM thinner so that the concentration of each metal element is 1000 ppt Metal analysis: ICP-MS (Agilent 8900) is used

[0127] Test Procedure: (PGMEA Purification) [1] A PGMEA simulated solution was prepared as described above. [2] The PGMEA simulated solution was passed through each resin in an amount 20 times the volume of the resin. [3] After [2], a sample for metal analysis was taken and metal analysis was performed.

[0128]

[0129] The results of Test 6 showed that by treating the material with a combination of a chelate resin containing an N-methylglucamine group (anion exchanger B) and a free basic weak anion exchange resin (anion exchanger A-2), and then removing the metal using an H-type chelate ion exchanger (cation exchanger), it was possible to reduce the amount of cationic impurities that could not be reduced by the combination of anion exchanger A-2 and anion exchanger B alone.

[0130] <Test 7> Test 7 involved using a chelate resin containing an N-methylglucamine group (anion exchanger B) alone, and HCO3. ３Silicon was removed using a combination of an anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B). The results of Test 7 are shown in Table 8.

[0131] [Experimental Method] Anion exchanger A-1: ​​ORLITE (registered trademark) A-P5200 HCO3 (ionic form: HCO3) ３ Form, functional group: quaternary amine), resin volume: 25 mL Anion exchanger B: ORLITE (registered trademark) X-U653J (ionic form: free base form, functional group: N-methylglucamine group), resin volume: 25 mL Mixture: The above anion exchanger A-1 and the above anion exchanger B are mixed in a volume ratio of 1:1 Column: Fluoropolymer (PFA) column, outer diameter 19 mm, height 300 mm Fluid flow rate: SV5 (h －１ ) Back pressure: Pressurized to 0.05-0.1 MPa inside the ion exchange resin column via an orifice placed downstream of the column Stock solution: IPA SE grade (Tokuyama) IPA dummy solution: Prepared by adding ICP-MS standard solution (SPEX) to the stock solution IPA SE to achieve a silicon concentration of 20 ppb Metal analysis: ICP-MS (Agilent 8900) is used

[0132] Test Procedure: (IPA Purification) [1] An IPA simulant solution was prepared as described above. [2] The IPA simulant solution was passed through each resin in an amount 20 times the volume of the resin. [3] After [2], a sample for metal analysis was taken and metal analysis was performed.

[0133]

[0134] Based on the results of Test 7, a single bed of chelate resin containing an N-methylglucamine group (anion exchanger B), HCO3 ３Both the (A-1) + B mixed bed, consisting of a shaped anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B), were able to reduce the amount of boron impurities in the IPA. It was confirmed that the silicon concentration was reduced from approximately 20 ppb to 10 ppb or less. Compared to boron, there was no significant difference between the B single bed and the (A-1) + B mixed bed in reducing silicon. However, the (A-1) + B mixed bed showed higher boron reduction performance than the B single bed and comparable silicon reduction performance, indicating that it has superior impurity reduction performance.

[0135] <Test 8> Test 8 is HCO ３ The treatment was carried out using a combination of an anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B), and the presence or absence of carbon dioxide generation was confirmed. The results of Test 8 are shown in Table 9.

[0136] [Experimental Method] Anion exchanger A-1: ​​ORLITE (registered trademark) A-P5200 HCO3 (ionic form: HCO3) ３ Form, functional group: quaternary amine), resin volume: 25 mL Anion exchanger B: ORLITE (registered trademark) X-U653J (ionic form: free base form, functional group: N-methylglucamine group), resin volume: 25 mL Mixture: The above anion exchanger A-1 and the above anion exchanger B are mixed in a volume ratio of 1:1 Column: Fluoropolymer (PFA) column, outer diameter 19 mm, height 300 mm Fluid flow rate: SV5 (h －１ ) Back pressure: Pressurize the ion exchange resin column to 0.05-0.1 MPa using an orifice placed downstream of the column. Stock solution: Tokuso IPA (manufactured by Tokuyama) IPA simulant solution: Add ICP-MS standard solution (manufactured by SPEX) and prepare so that the concentration of each metal element reaches 100 ppt. Verification method: Visually check for the presence or absence of bubbles in the column.

[0137] Test procedure: [1] Pack the water-moistened mixture of A and B into the column. [2] Add 50 times the amount of IPA, SV5 (h －１[3] Confirm that the water content in the IPA after passing through is within 130% of the water content in the IPA before passing through, and that the water has been sufficiently replaced by IPA, by measuring the water content in the IPA after passing through using the Karl Fischer (KF) method with a Karl Fischer moisture meter (HIRANUMA, AQ-2200F). [4] Visually check for bubbles in the column. [5] Remove the orifice at the end of the column and pass 20 times the amount of IPA simulated solution through at atmospheric pressure for 4 hours. [6] Confirm that the water content in the IPA after passing through is within 130% of the water content in the simulated solution and that no water contamination has occurred. [7] Visually check for bubbles in the column.

[0138]

[0139] Based on the results of Test 8, HCO ３ By pressurizing a container containing a mixture of anion exchange resin (anion exchanger A-1) and a chelate resin containing an N-methylglucamine group (anion exchanger B) to 0.05 MPa or higher, the generation of bubbles, which are thought to be carbon dioxide, could be suppressed.

[0140] 1, 2, 3, 4, 5, 6 Purification equipment, 10, 12, 14, 16 Containers, 20, 22, 24, 26, 28, 30, 36 Piping, 32 Circulation piping, 34 Filtration equipment.

Claims

1. A method for purifying an organic solvent, comprising an anion exchanger contact step of contacting the organic solvent to be purified with anion exchanger A and anion exchanger B, wherein anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and anion exchanger B is a chelate resin containing a glucamine-type ion exchanger.

2. A method for purifying an organic solvent according to claim 1, characterized in that, in the anion exchanger contact step, the organic solvent is brought into contact with a mixture of anion exchanger A and anion exchanger B, or the organic solvent is brought into contact with anion exchanger A and then with anion exchanger B.

3. A method for purifying an organic solvent according to claim 1 or 2, characterized in that, after the anion exchanger contact step, the organic solvent that has been in contact with anion exchanger A and anion exchanger B is brought into contact with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger.

4. A method for purifying an organic solvent according to any one of claims 1 to 3, characterized in that the anion exchanger A and the anion exchanger B are an anion exchange resin.

5. A method for purifying an organic solvent according to any one of claims 1 to 4, characterized in that the organic solvent to be purified contains at least one selected from the group consisting of methanol, ethanol, isopropanol, N-methyl-2-pyrrolidone, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate.

6. A method for purifying an organic solvent according to any one of claims 1 to 5, characterized in that the organic solvent to be purified has a concentration of at least one impurity selected from the group consisting of boron, silicon, iron, and chromium of 10 ppt or more.

7. An organic solvent purification apparatus comprising an anion exchanger contact means for contacting the organic solvent to be purified with anion exchanger A and anion exchanger B, wherein anion exchanger A is an anion exchanger having at least one ionic form selected from the group consisting of OH form, free base form, carbonate form, and bicarbonate form, and anion exchanger B is a chelate resin containing a glucamine-type ion exchange group.

8. An organic solvent purification apparatus according to claim 7, wherein the anion exchanger contact means comprises a container containing a mixture of anion exchanger A and anion exchanger B, and the organic solvent is brought into contact with the mixture of anion exchanger A and anion exchanger B, or the anion exchanger contact means comprises a container containing anion exchanger A and a container containing anion exchanger B, and the organic solvent is brought into contact with anion exchanger A and then with anion exchanger B.

9. An organic solvent purification apparatus according to claim 8, characterized in that a container containing a mixture of the anion exchanger A and the anion exchanger B, or a container containing the anion exchanger A and a container containing the anion exchanger B are pressurized to 0.05 MPa or higher.

10. An organic solvent purification apparatus according to any one of claims 7 to 9, further comprising a cation exchanger contact means for bringing the organic solvent that has been in contact with the anion exchanger A and the anion exchanger B into contact with at least one of an H-type cation exchanger and an H-type chelate-type ion exchanger.

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