Method for purifying organic solvent, method for producing purified organic solvent, and organic solvent purification system

Abstract

To provide a method for purifying an organic solvent, a method for producing a purified organic solvent, and an organic solvent purification system, enabling the removal of impurity cations from an organic solvent to be treated.SOLUTION: A method for purifying an organic solvent comprises a step of bringing a to-be-treated organic solvent, which contains an organic solvent and impurity cations, into contact with a first ion exchanger to remove the impurity cations, wherein the first ion exchanger comprises a chelating resin having an N-methylglucamine group.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for purifying an organic solvent by removing impurity cations from an organic solvent to be treated, a method for producing a purified organic solvent, and a system for purifying an organic solvent. [Background technology]

[0002] Organic solvents are used in various industrial fields, and it is necessary to remove impurities contained in the organic solvent depending on the application or purpose of the organic solvent. For example, in the semiconductor manufacturing process, organic solvents such as isopropanol are used to clean semiconductor wafers. If impurities are contained in this cleaning organic solvent, they may adversely affect the semiconductor wafers, so it is necessary to remove the impurities in the organic solvent.

[0003] As a method for removing impurities from an organic solvent and purifying the organic solvent, a method for purifying an organic solvent that is excellent in removing metal impurities from the organic solvent is disclosed in Patent Document 1. In this method for purifying an organic solvent, metal impurities (monovalent and polyvalent metal cations, etc.) contained in the organic solvent are removed using an H-type chelate exchanger, an anion exchanger, and an H-type strongly acidic cation exchanger. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 217911 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] In the method for purifying an organic solvent in Patent Document 1, a packed column packed with various ion exchangers is used to remove various metal impurities from the organic solvent. In particular, to enhance the removal of polyvalent metal cations, an iminodiacetic acid group, an aminomethylphosphate group, or an iminopropionic acid group is used as the functional group of the H-type chelate exchanger (ion exchanger). The H-type chelate exchanger can remove polyvalent metal cations by releasing the hydrogen ion possessed by the functional group and capturing the polyvalent metal cation in its place by coordinating it. However, there is room for improvement in terms of the performance of removing impurity cations in organic solvents.

[0006] Under these circumstances, the present invention aims to provide a method for producing a purified organic solvent and a system for purifying an organic solvent, which have excellent performance for removing impurity cations in an organic solvent and use functional groups different from those of the H-type chelate exchangers that have been conventionally used, and which remove impurity cations contained in an organic solvent. [Means for solving the problem]

[0007] The present inventors conducted extensive research to solve the above problems and discovered that a chelating resin having an N-methylglucamine group, which has conventionally been used as an ion exchange resin that selectively adsorbs boron, has excellent performance for removing impurity cations (particularly polyvalent metal cations) from organic solvents, thereby completing the present invention.

[0008] The present invention relates to the following inventions. <1> A method for purifying an organic solvent, comprising a step of contacting an organic solvent to be treated, which contains an organic solvent and impurity cations, with a first ion exchanger to remove the impurity cations, wherein the first ion exchanger contains a chelating resin having an N-methylglucamine group. <2> The impurity cation is a polyvalent metal cation. <1> 2. A method for purifying an organic solvent according to claim 1. <3> The organic solvent is at least one organic solvent selected from the group consisting of methanol, ethanol, isopropanol, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate. <1> or <2> 2. A method for purifying an organic solvent according to claim 1. <4> <1> from <3> The method for purifying an organic solvent according to any one of the above items 1 to 5, further comprising the step of: (A) A treatment in which the organic solvent to be treated containing the impurity cations is first contacted with a single bed of the first ion exchanger, and then contacted with a single bed of the second ion exchanger. (B) A treatment in which the organic solvent to be treated containing the impurity cations is first contacted with a single bed of the second ion exchanger, and then with a single bed of the first ion exchanger. (C) contacting the organic solvent containing the impurity cations with a mixed bed of the first ion exchanger and the second ion exchanger; <5> The second ion exchanger includes a cation exchange resin having one or more functional groups selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, a phosphinic acid group, a phenoxide group, and an arsenous acid group. <4> 2. A method for purifying an organic solvent according to claim 1. <6> <1> from <5> 2. A method for producing a purified organic solvent, comprising the step of using the method for purifying an organic solvent according to claim 1. <7> The purified organic solvent is a solvent for cleaning semiconductor substrates. <6> 2. A method for producing the purified organic solvent according to claim 1 .

[0009] <1A> A system for purifying an organic solvent, comprising a purification means having a first ion exchanger through which an organic solvent and an organic solvent to be treated containing impurity cations are passed, the first ion exchanger including a chelating resin having an N-methylglucamine group. <2A> The system for purifying an organic solvent according to <1A>, wherein the impurity cation is a polyvalent metal cation. <3A> The system for purifying an organic solvent according to any one of <1A> and <2A>, comprising: the first ion exchanger and a second ion exchanger containing a cation exchange resin; and any one of the following purification means (A) to (C). (A) a purification means having a single bed of the first ion exchanger through which the organic solvent to be treated is passed, and a single bed of the second ion exchanger through which the treated liquid from the single bed of the first ion exchanger is passed; (B) a purification means having a single bed of the second ion exchanger through which the organic solvent to be treated is passed, and a single bed of the first ion exchanger through which the treated liquid from the single bed of the second ion exchanger is passed. (C) a purification means having a mixed bed containing the first ion exchanger and the second ion exchanger through which the organic solvent to be treated is passed; <4A> The system for purifying an organic solvent according to <3A>, wherein the second ion exchanger contains a cation exchange resin having one or more functional groups selected from the group consisting of a sulfonic acid group, a carboxylate group, a phosphonic acid group, a phosphinic acid group, a phenoxide group and an arsenous acid group. <5A> The system for purifying an organic solvent according to any one of <1A> to <4A>, wherein the organic solvent is one or more organic solvents selected from the group consisting of methanol, isopropanol, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate. <6A> A method for producing a purified organic solvent, using the organic solvent purification system according to any one of <1A> to <5A>. <7A> The method for producing a purified organic solvent according to <6A>, wherein the purified organic solvent is a solvent for cleaning semiconductor substrates. Effect of the Invention

[0010] According to the present invention, there are provided a method for purifying an organic solvent, a method for producing a purified organic solvent, and a system for purifying an organic solvent, which remove impurity cations from an organic solvent to be treated. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is a diagram showing a system for purifying an organic solvent according to an embodiment of the present invention (single bed of a first ion exchanger). [Diagram 2] FIG. 2 is a diagram showing a system for purifying an organic solvent according to another embodiment of the present invention (front stage: single bed of a first ion exchanger, rear stage: single bed of a second ion exchanger). [Diagram 3] FIG. 2 is a diagram showing a system for purifying an organic solvent according to another embodiment of the present invention (front stage: single bed of a second ion exchanger, rear stage: single bed of a first ion exchanger). [Figure 4] FIG. 2 is a diagram showing a system for purifying an organic solvent according to another embodiment of the present invention (a mixed bed of a first ion exchanger and a second ion exchanger). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples, and can be modified as desired without departing from the gist of the present invention. In this specification, the word "~" is used as an expression including the numerical value or physical quantity before and after it. In this specification, the expression "A and / or B" includes "A only," "B only," and "both A and B."

[0013] <1. Purification method of organic solvent> The method for purifying an organic solvent of the present invention includes a step of contacting an organic solvent to be treated, which contains an organic solvent and impurity cations, with a first ion exchanger to remove the impurity cations, and is characterized in that the first ion exchanger contains a chelating resin having an N-methylglucamine group. In the following, the "chelating resin having an N-methylglucamine group" may be referred to as the "N-methylglucamine type chelating resin".

[0014] In the present invention, the term "impurity cation" refers to a cationic impurity contained in an organic solvent. The details of the impurity cation will be described later. In the present invention, the term "organic solvent to be treated (containing an organic solvent and an impurity cation)" means "an organic solvent to be treated containing an impurity cation." In the present invention, the term "organic solvent" refers to an organic compound used as a solvent. In this specification, "removing impurity cations" does not only mean completely removing the impurity cations from the organic solvent to be treated, but also includes removing a portion of the impurity cations from the organic solvent to be treated.

[0015] One of the features of the method for purifying an organic solvent of the present invention is that it includes a step of contacting the organic solvent to be treated with a first ion exchanger containing an N-methylglucamine type chelating resin. Through this step, it becomes possible to efficiently remove impurity cations (particularly polyvalent metal cations) from the organic solvent to be treated.

[0016] N-methylglucamine-type chelating resins are known to have the ability to adsorb boron in aqueous solutions, and are widely used to remove boron from the target solution to be treated. For example, N-methylglucamine-type chelating resins are used to adsorb and remove boron borate (anion) from boron-containing water.

[0017] On the other hand, the present invention is based on the discovery that N-methylglucamine-type chelating resins have the ability to adsorb impurity cations in organic solvents. Although the details of the mechanism by which N-methylglucamine-type chelating resins adsorb impurity cations in organic solvents are not clear at present, it is presumed that the effect of the organic solvent on the N-methylglucamine group, particularly the physical properties of the organic solvent (e.g., polarity, hydrophilicity, etc.), is an influence. It is presumed that in the method for purifying an organic solvent of the present invention, the N-methylglucamine group of the chelating resin adsorbs cations in the organic solvent, making it possible to remove impurity cations from the organic solvent being treated.

[0018] The present invention will now be described in more detail.

[0019] [Chelating resin with N-methylglucamine group] The chelating resin having an N-methylglucamine group (N-methylglucamine type chelating resin) includes a chelating resin in which an N-methylglucamine group represented by the following formula (1) is bonded to a base polymer.

[0020] [ka]

[0021] As the base polymer, any polymer can be used as long as it does not impair the object of the present invention, and examples thereof include styrene-based crosslinked copolymers and (meth)acrylic crosslinked copolymers. In the present invention, "(meth)acrylic" refers to a combination of "acrylic" and "methacrylic".

[0022] In the present invention, the term "styrene-based cross-linked copolymer" refers to a cross-linked copolymer obtained by copolymerizing a monovinyl aromatic monomer with a cross-linkable aromatic monomer, and the term "(meth)acrylic cross-linked copolymer" refers to a cross-linked copolymer obtained by copolymerizing a (meth)acrylic monomer with a cross-linkable (meth)acrylic monomer.

[0023] Examples of the monovinyl aromatic monomer include alkyl-substituted styrenes such as styrene, methylstyrene, and ethylstyrene, and halogen-substituted styrenes such as bromostyrene. These may be used alone or in combination of two or more. Among them, styrene or a monomer mainly composed of styrene is preferred as the monovinyl aromatic monomer.

[0024] Examples of the crosslinkable aromatic monomer include divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, divinylxylene, divinylbiphenyl, bis(vinylphenyl)methane, bis(vinylphenyl)ethane, bis(vinylphenyl)propane, and bis(vinylphenyl)butane. These may be used alone or in combination of two or more. Among them, divinylbenzene is preferred as the crosslinkable aromatic monomer. Industrially produced divinylbenzene usually contains a large amount of ethylvinylbenzene (ethylstyrene) as a by-product, but such divinylbenzene can also be used in the present invention.

[0025] Examples of (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, iso-(meth)acrylate, iso-butyl (meth)acrylate, t-butyl (meth)acrylate, n-butyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, butyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxy-3-chloropropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0026] Examples of the crosslinkable (meth)acrylic monomer include polymethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0027] N-methylglucamine type chelating resins have an excellent ability to adsorb and remove impurity cations, particularly polyvalent metal cations, in organic solvents. Among the N-methylglucamine type chelating resins, an N-methylglucamine type chelating resin represented by the following formula (2), in which an N-methylglucamine group is bonded to a styrene-based crosslinked copolymer, is particularly preferred.

[0028] [ka]

[0029] Specific examples of commercially available N-methylglucamine type chelating resins include 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.), DIAION (registered trademark) CRB03 (manufactured by Mitsubishi Chemical Corporation), DIAION (registered trademark) CRB05 (manufactured by Mitsubishi Chemical Corporation), AMBERLITE (registered trademark) IRA743 (manufactured by Organo Corporation), AMBERTEC UP7530 (manufactured by DuPont), and the like.

[0030] In addition, the N-methylglucamine type chelating resin may be a gel type or a porous type. In addition, resins generally called "high-porous type" are also included in the meaning of "porous type" in the present invention.

[0031] The N-methylglucamine type chelating resin used in the present invention may have a high or low uniformity of particle size, as long as the object of the present invention is not impaired. Specifically, the average particle size of the N-methylglucamine type chelating resin used in the present invention is usually 200 μm to 1000 μm.

[0032] The average particle size can be measured by a known method, for example, an image processing method (spreading a chelating resin on a petri dish, taking an image of the chelating resin with a microscope connected to a digital camera, and then processing the outline of the image to determine the particle size).

[0033] [Organic solvent to be treated] The organic solvent to be treated according to the present invention is an organic solvent before purification treatment, and contains an organic solvent and impurity cations. In this specification, the purification treatment means a treatment in which an organic solvent to be treated, which contains an organic solvent and impurity cations, is brought into contact with a first ion exchanger to remove the impurity cations.

[0034] In the present invention, the organic solvent may be any organic solvent as long as it does not impair the object of the present invention, and may be either a polar organic solvent or a non-polar organic solvent, but a polar organic solvent is preferred. A polar organic solvent is an organic solvent that has a polar group (hydrophilic group) in the molecule, and it is presumed that the polar group (hydrophilic group) acts on the N-methylglucamine group, thereby improving the adsorption ability of metal cations.

[0035] There are no limitations on the polar organic solvent as long as it is a compound having a polar group, and examples thereof include alcohols, ethers, formamides, pyrrolidones, ketones, lactones, esters, and sulfoxides having a polar group.

[0036] From the viewpoint of the performance of removing impurity cations by the N-methylglucamine type chelating resin, the polar organic solvent is preferably an alcohol, an ether, or an ester. Examples of alcohols include methanol, ethanol, isopropanol, and 1-methoxy-2-propanol. Examples of ethers include propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, and diethylene glycol butyl ether. Examples of esters include propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, tripropylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethylene glycol propyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol propyl ether acetate, and diethylene glycol butyl ether acetate; Examples include:

[0037] Among the organic solvents, the alcohols methanol, ethanol, isopropanol, and 1-methoxy-2-propanol, and the esters propylene glycol monomethyl ether acetate can be mentioned as suitable targets. At least one of these suitable targets of the organic solvent can be selected and used.

[0038] Furthermore, when the polar organic solvent is 1-methoxy-2-propanol or propylene glycol monomethyl ether acetate, it is possible to remove not only polyvalent metal cations but also monovalent metal cations (alkali metal ions), as shown in the examples.

[0039] [Impurity cations] In the present invention, the impurity cations are not particularly limited as long as they are cationic impurities that can be adsorbed and removed by the N-methylglucamine-type chelating resin, and any of metal cations, organometallic cations, and nonmetallic cations can be removed.

[0040] In the present invention, a typical example of an impurity cation is a metal cation. Specific examples of metal cations include monovalent metal cations obtained by ionizing lithium, sodium, potassium, etc., and polyvalent metal cations obtained by ionizing calcium, magnesium, strontium, barium, aluminum, tin, iron, nickel, copper, zinc, lead, cadmium, manganese, chromium, vanadium, molybdenum, chromium, zirconium, silver, mercury, antimony, titanium, bismuth, gallium, thallium, etc. The organic solvent to be treated may contain one or more of these metal cations. From the viewpoint of the removal performance of the N-methylglucamine type chelating resin, polyvalent metal cations (divalent or higher metal cations) are the preferred targets of the present invention.

[0041] In an organic solvent, the N-methylglucamine type chelating resin has an excellent ability to remove polyvalent metal cations among impurity cations, and among the polyvalent metal cations, heavy metal cations such as aluminum, calcium, chromium, titanium, manganese, iron, nickel, cobalt, copper, zinc, cadmium, and lead are the preferred targets of the present invention.

[0042] The content of each metal cation (impurity cation) in the organic solvent to be treated is not particularly limited, but is typically 100 ppt by mass to 300 ppb by mass.

[0043] In the present invention, the content of each metal cation (impurity cation) contained in the organic solvent can be measured by an inductively coupled plasma mass spectrometer (ICP-MS).

[0044] [Organic solvent purification methods (1) and (2)] As described above, N-methylglucamine-type chelating resins have excellent performance in removing polyvalent metal cations from organic solvents, but their performance in removing monovalent metal cations (alkali metal ions) may be inferior to that of polyvalent metal cations. In order to more effectively remove monovalent metal cations (alkali metal ions), the method for purifying an organic solvent of the present invention may use, in addition to the first ion exchanger, a second ion exchanger containing a cation exchange resin.

[0045] Hereinafter, in the method for purifying an organic solvent of the present invention, the method using only the first ion exchanger will be referred to as "method for purifying an organic solvent of the present invention (1)", and the method using the first ion exchanger and the second ion exchanger (above (A) to (C)) will be referred to as "method for purifying an organic solvent of the present invention (2)".

[0046] The method (1) for purifying an organic solvent of the present invention uses a first ion exchanger containing a chelating resin having an N-methylglucamine group to remove impurity cations from an organic solvent to be treated. The method (1) for purifying an organic solvent of the present invention uses only the first ion exchanger, and therefore the process can be simplified.

[0047] The treatment conditions in the method (1) for purifying an organic solvent of the present invention may be any conditions that can remove the target impurity cations, and can be appropriately determined depending on the type and amount of the first ion exchanger used, the type and amount of the organic solvent treated, the type and amount of the impurity cations contained (concentration), etc. The flow rate SV of the organic solvent to be treated is, for example, 0.1 to 50 h -1 , preferably 1 to 10 hours -1 The temperature of the organic solvent to be treated can be, for example, 0 to 50°C.

[0048] The method (2) for purifying an organic solvent of the present invention includes any one of the following treatments (A) to (C) using the first ion exchanger and a second ion exchanger containing a cation exchange resin: (A) A treatment in which the organic solvent to be treated containing the impurity cations is first contacted with a single bed of the first ion exchanger, and then contacted with a single bed of the second ion exchanger. (B) A treatment in which the organic solvent to be treated containing the impurity cations is first contacted with a single bed of the second ion exchanger, and then with a single bed of the first ion exchanger. (C) contacting the organic solvent containing the impurity cations with a mixed bed of the first ion exchanger and the second ion exchanger;

[0049] The method (2) for purifying an organic solvent of the present invention further uses a second ion exchanger containing a cation exchange resin in addition to the first ion exchanger, thereby making it possible to effectively remove impurity cations, particularly monovalent metal cations (alkali metal ions), from the organic solvent to be treated which cannot be sufficiently removed by the first ion exchanger containing an N-methylglucamine-type chelating resin alone.

[0050] In the method (2) for purifying an organic solvent of the present invention, the second ion exchanger containing a cation exchange resin may be any type as long as it does not impair the object of the present invention, and may be appropriately selected depending on the organic solvent to be treated.

[0051] The structure of the cation exchange resin contained in the second ion exchanger may be a gel type or a porous type (MP type (macroporous type) or MR type (macrotreticular type)), and it is preferable to use a cation exchange resin such as a styrene-based or acrylic-based resin.

[0052] The cation exchange resin contained in the second ion exchanger contains functional groups such as sulfonic acid groups, carboxylic acid groups, phosphonic acid groups, phosphinic acid groups, phenoxide groups, and arsenous acid groups, and is classified into strong acid cation exchange resins and weak acid cation exchange resins depending on the type of functional group. The cation exchange resin contained in the second ion exchanger may be either a strongly acidic cation exchange resin or a weakly acidic cation exchange resin, but a strongly acidic cation exchange resin, which has better performance in removing monovalent metal cations (alkali metal ions), is preferably used.

[0053] As the strongly acidic cation exchange resin, commercially available products may be used, such as MUROMAC (registered trademark) XSC series (manufactured by Muromachi Chemical Co., Ltd.), MUROMAC (registered trademark) XMC series (manufactured by Muromachi Chemical Co., Ltd.), AMBERLITE (registered trademark) HPR series (manufactured by DuPont), DIAION (registered trademark) SK series, PK series, UBK series (manufactured by Mitsubishi Chemical Corporation), OLITE (registered trademark) DS series (manufactured by Organo Corporation), and Lewatit (registered trademark) Monoplus series (manufactured by Lanxess KK).

[0054] The embodiment (A) of the method (2) for purifying an organic solvent of the present invention comprises a process of first contacting the organic solvent containing the impurity cations with a single bed of the first ion exchanger and then contacting the organic solvent with a single bed of the second ion exchanger.

[0055] The embodiment (B) of the method (2) for purifying an organic solvent of the present invention comprises a process of first contacting the organic solvent containing the impurity cations with a single bed of the second ion exchanger and then contacting the organic solvent with a single bed of the first ion exchanger.

[0056] Moreover, embodiment (C) of the method (2) for purifying an organic solvent of the present invention comprises a treatment of contacting the organic solvent containing the impurity cations with a mixed bed of the first ion exchanger and the second ion exchanger.

[0057] The aspects (A) to (C) of the method (2) for purifying an organic solvent of the present invention will be explained in the system for purifying an organic solvent of the present invention described below.

[0058] The treatment conditions in the method for purifying an organic solvent (2) of the present invention may be any conditions that can remove the target impurity cations, and can be appropriately determined depending on the type and amount of the first ion exchanger and the second ion exchanger used, the type and amount of the organic solvent treated, the type and amount of the impurity cations contained (concentration), etc. The flow rate SV of the organic solvent to be treated is, for example, 0.1 to 50 h -1 , preferably 1 to 10 hours -1 The temperature of the organic solvent to be treated can be, for example, 0 to 50°C.

[0059] [Method of producing purified organic solvent] The method for producing a purified organic solvent of the present invention uses the method for purifying an organic solvent of the present invention to remove impurity cations from the organic solvent to be treated. That is, the method for producing a purified organic solvent of the present invention includes a step of using the method for purifying an organic solvent of the present invention. Hereinafter, the step of using the method for purifying an organic solvent of the present invention may be referred to as the "purification step of the present invention."

[0060] The method for producing a purified organic solvent of the present invention may comprise only the purification step of the present invention, or may comprise, in addition to the purification step of the present invention, any treatment step other than the purification step of the present invention, as long as the method can produce the desired purified organic solvent. The purified organic solvent according to the present invention is an organic solvent from which impurity cations have been removed by at least the purification step of the present invention. The purified organic solvent according to the present invention may be an organic solvent that has been subjected to any treatment step other than the purification step of the present invention, depending on the application or purpose. Examples of the treatment steps other than the purification step in the present invention include a filtration step, a precipitation step, an addition step, a neutralization step, and a dehydration step.

[0061] A purified organic solvent is produced by the method for producing a purified organic solvent of the present invention, and the purified organic solvent according to the present invention may contain any component (additional component such as a surfactant) in the target organic solvent, as long as the object of the present invention is not impaired.

[0062] In the present invention, one suitable example of the target purified organic solvent is a solvent for cleaning semiconductor substrates. Since the purified organic solvent according to the present invention has impurity cations removed through the purification process of the present invention, even when the purified organic solvent is used as a solvent for cleaning semiconductor substrates, the impurity cations do not adversely affect the semiconductor substrates, and the semiconductor substrates can be cleaned without any problems.

[0063] <2. Organic solvent purification system> As the organic solvent purification system for carrying out the organic solvent purification method of the present invention, any purification system can be used as long as it does not impair the object of the present invention, and can be appropriately determined depending on the type and treatment amount of the organic solvent, the type and content (concentration) of the impurity cations, etc. For example, this can be suitably carried out by the organic solvent purification system of the present invention described below.

[0064] The organic solvent purification system of the present invention is a system for purifying an organic solvent, which has a purification means equipped with a first ion exchanger through which an organic solvent and an organic solvent to be treated containing impurity cations are passed, and the first ion exchanger contains an N-methylglucamine-type chelating resin.

[0065] The organic solvent purification system of the present invention is a system for carrying out the organic solvent purification method of the present invention. In the following description of the organic solvent purification system of the present invention, descriptions overlapping with those of the organic solvent purification method of the present invention described above (such as the first ion exchanger, the second ion exchanger, and the organic solvent to be treated) may be omitted.

[0066] The organic solvent purification system of the present invention has a purification means equipped with a first ion exchanger through which an organic solvent to be treated containing an organic solvent and impurity cations is passed, and the first ion exchanger contains an N-methylglucamine-type chelating resin. The organic solvent purification system of the present invention can have any configuration as long as it is possible to pass an organic solvent to be treated containing an organic solvent and impurity cations through the first ion exchanger and remove the impurity cations. That is, the system for purifying an organic solvent of the present invention may use only the first ion exchanger as a purification means for carrying out the method for purifying an organic solvent (1) of the present invention, or may use the first ion exchanger and the second ion exchanger for carrying out the method for purifying an organic solvent (2) of the present invention.

[0067] When carrying out the above-mentioned method (1) for purifying an organic solvent of the present invention, the purification system for a purified organic solvent of the present invention can use a purification means having a single bed of a first ion exchanger.

[0068] When carrying out the above-mentioned method (2) for purifying a purified organic solvent of the present invention, the system for purifying an organic solvent of the present invention includes any one of the following purification means (A) to (C). (A) a purification means having a single bed of the first ion exchanger through which the organic solvent to be treated is passed, and a single bed of the second ion exchanger through which the treated liquid from the single bed of the first ion exchanger is passed; (B) a purification means having a single bed of the second ion exchanger through which the organic solvent to be treated is passed, and a single bed of the first ion exchanger through which the treated liquid from the single bed of the second ion exchanger is passed. (C) a purification means having a mixed bed containing the first ion exchanger and the second ion exchanger through which the organic solvent to be treated is passed;

[0069] Hereinafter, a system for purifying an organic solvent according to an embodiment of the present invention, which further uses a second ion exchanger containing a cation exchange resin, will be described with reference to the drawings. In addition, the dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In addition, in all drawings, similar components are given similar reference numerals, and descriptions thereof will be omitted as appropriate.

[0070] [First embodiment] FIG. 1 shows a system 1 for purifying an organic solvent according to a first embodiment of the present invention. The organic solvent purification system 1 includes a packed tower 10 which is a single bed of a first ion exchanger, a supply means (not shown) for supplying the organic solvent to be treated to the packed tower 10, and a recovery means (not shown) for recovering the purified organic solvent purified in the packed tower 10.

[0071] The first embodiment is an example in which a single bed of a first ion exchanger is used as a purification means to carry out the organic solvent purification method (1) of the present invention.

[0072] In the first embodiment, the first ion exchanger, the organic solvent to be treated, and the purified organic solvent are as described above in <1. Method for purifying organic solvent of the present invention>, and therefore description thereof will be omitted.

[0073] A conventionally known packed tower used in liquid purification technology is used as the packed tower 10, except that a first ion exchanger is used. The packed tower 10 is a tower packed with a single bed of the first ion exchanger. By passing the organic solvent to be treated through the packed tower 10, the organic solvent to be treated can be brought into contact with the first ion exchanger. The supplying means and the recovering means may be conventionally known devices used in liquid purification techniques. For example, the supplying means may be one equipped with a storage tank for storing the organic solvent to be treated, a pump for delivering the organic solvent to be treated, a liquid delivery pipe through which the organic solvent to be treated flows, etc. The recovering means may be one equipped with a liquid delivery pipe through which the purified organic solvent flows, a storage tank for storing the purified organic solvent, etc.

[0074] The organic solvent purification system 1 according to the first embodiment is suitable for cases in which the organic solvent to be treated does not contain any monovalent impurity cations (alkali metal ions), or if any are contained, the concentration is extremely low, or for cases in which it is not necessary to remove the monovalent impurity cations (alkali metal ions) contained in the purified organic solvent to an extremely low concentration.

[0075] [Second embodiment] FIG. 2 shows a system 1A for purifying an organic solvent according to a second embodiment of the present invention. The organic solvent purification system 1A includes a packed tower 10 which is a single bed of a first ion exchanger, a packed tower 20 which is a single bed of a second ion exchanger connected in series to the packed tower 10 via piping, a supply means (not shown) for supplying the organic solvent to be treated to the packed tower 10, and a recovery means (not shown) for recovering the organic solvent that has been purified through the packed towers 10 and 20.

[0076] The second embodiment is an example in which a purification means having a single bed of a first ion exchanger through which the organic solvent to be treated is passed and a single bed of the second ion exchanger through which the treated liquid from the single bed of the first ion exchanger is passed is used to carry out the aspect (A) of the purification method (2) of the present invention.

[0077] In the second embodiment, the first ion exchanger, the second ion exchanger, the organic solvent to be treated, and the purified organic solvent are as described in <1. Method for purifying organic solvent of the present invention> above, and therefore their description will be omitted.

[0078] The packed towers 10 and 20 are conventionally known packed towers used in liquid purification technology, except that a first ion exchanger and a second ion exchanger are used, respectively. The packed tower 10 is a tower packed with a single bed of the first ion exchanger, and the packed tower 20 is a tower packed with a single bed of the second ion exchanger. By passing the organic solvent to be treated through the packed towers 10 and 20, the organic solvent to be treated can be brought into contact with the first ion exchanger and the second ion exchanger. Moreover, the supply means and the recovery means are as described above (first embodiment), and therefore the description thereof will be omitted.

[0079] The organic solvent purification system 1A according to the second embodiment is suitable for cases where the organic solvent to be treated contains a high concentration of monovalent impurity cations (alkali metal ions) or where it is necessary to remove the monovalent impurity cations (alkali metal ions) contained in the purified organic solvent to an extremely low concentration.

[0080] As shown in FIG. 2, in a purification system 1A for an organic solvent, the organic solvent to be treated containing impurity cations is first brought into contact with a packed tower 10 (first ion exchanger) and then with a packed tower 20 (second ion exchanger).

[0081] According to such a configuration, the organic solvent to be treated is first passed through a single bed (packed tower 10) of the first ion exchanger containing an N-methylglucamine-type chelating resin, and impurity cations are removed by the first ion exchanger, thereby reducing the ionic load on the single bed (packed tower 20) of the second ion exchanger containing a cation exchange resin located downstream.

[0082] In particular, the efficiency of removing impurity cations by the cation exchange resin can be increased by first removing impurity cations from the organic solvent to be treated using a first ion exchanger containing a chelating resin suitable for removing polyvalent impurity cations, and then using a second ion exchanger containing a cation exchange resin. In addition, the second ion exchanger containing a cation exchange resin can reliably remove monovalent impurity cations (alkali metal ions) that are relatively difficult to remove by the first ion exchanger containing an N-methylglucamine-type chelating resin.

[0083] [Third embodiment] FIG. 3 shows a system 1B for purifying an organic solvent according to a third embodiment of the present invention. The organic solvent purification system 1B includes a packed tower 20 having a single bed of a second ion exchanger, a packed tower 10 having a single bed of a first ion exchanger connected in series to the packed tower 10 via piping, a supply means (not shown) for supplying the organic solvent to be treated to the packed tower 20, and a recovery means (not shown) for recovering the purified organic solvent that has been purified through the packed tower 20 and the packed tower 10.

[0084] The third embodiment is an example in which a purification means having a single bed of a second ion exchanger through which the organic solvent to be treated is passed and a single bed of a first ion exchanger through which the treated liquid from the single bed of the second ion exchanger is passed is used to carry out the aspect (B) of the purification method (2) of the present invention.

[0085] In the third embodiment, the first ion exchanger, the second ion exchanger, the organic solvent to be treated, and the purified organic solvent are as described in <1. Method for purifying organic solvent of the present invention> above, and therefore their description will be omitted.

[0086] The packed towers 10 and 20 are as described above (in the second embodiment), and therefore the description thereof will be omitted. Moreover, the supply means and the recovery means are as described above (first embodiment), and therefore the description thereof will be omitted.

[0087] The organic solvent purification system 1B according to the third embodiment is suitable for cases in which the organic solvent to be treated contains a high concentration of monovalent impurity cations (alkali metal ions) or cases in which it is necessary to remove the monovalent impurity cations (alkali metal ions) contained in the purified organic solvent to an extremely low concentration.

[0088] As shown in FIG. 3, in a purification system 1B for an organic solvent, the organic solvent to be treated containing impurity cations is first brought into contact with a packed tower 20 (second ion exchanger) and then with a packed tower 10 (first ion exchanger).

[0089] According to such a configuration, the organic solvent to be treated is first passed through a single bed (packed tower 20) of the second ion exchanger containing a cation exchange resin, and impurity cations are removed, thereby reducing the ionic load on the single bed (packed tower 10) of the first ion exchanger containing an N-methylglucamine-type chelating resin in the downstream stage.

[0090] In particular, when the organic solvent to be treated contains monovalent and polyvalent impurity cations as impurity cations, the impurity cations are first removed using a second ion exchanger containing a cation exchange resin suitable for removing monovalent impurity cations, and then the first ion exchanger containing a chelating resin is used, thereby making it possible to increase the efficiency of removing impurity cations by the chelating resin. In addition, the second ion exchanger containing a cation exchange resin can reliably remove monovalent impurity cations (alkali metal ions) that are relatively difficult to remove by the first ion exchanger containing an N-methylglucamine-type chelating resin.

[0091] [Fourth embodiment] FIG. 4 shows a system 1C for purifying an organic solvent according to a fourth embodiment of the present invention. The organic solvent purification system 1C includes a packed tower 30 which is a mixed bed of a first ion exchanger and a second ion exchanger, a supply means (not shown) for supplying the organic solvent to be treated to the packed tower 30, and a recovery means (not shown) for recovering the organic solvent that has been purified through the packed tower 30. In the third embodiment, the first ion exchanger, the second ion exchanger, the organic solvent to be treated, and the purified organic solvent are as described in <1. Method for purifying organic solvent of the present invention> above, and therefore their description will be omitted.

[0092] A conventionally known packed tower used in liquid purification technology is used as the packed tower 30, except that the first ion exchanger and the second ion exchanger are used. The packed tower 30 is a tower packed with a mixed bed of the first ion exchanger and the second ion exchanger. By passing the organic solvent to be treated through the packed tower 30, the organic solvent to be treated can be brought into contact with the first ion exchanger and the second ion exchanger. Moreover, the supply means and the recovery means are as described above (first embodiment), and therefore the description thereof will be omitted.

[0093] The organic solvent purification system 1C according to the fourth embodiment is suitable for cases in which the organic solvent to be treated contains a high concentration of monovalent impurity cations (alkali metal ions) or cases in which it is necessary to remove the monovalent impurity cations (alkali metal ions) contained in the purified organic solvent to an extremely low concentration.

[0094] As shown in FIG. 4, in a purification system 1C for an organic solvent, a treatment is performed by contacting an organic solvent to be treated that contains impurity cations with a packed tower 30 that is a mixed bed of the first ion exchanger and the second ion exchanger.

[0095] According to such a configuration, the organic solvent to be treated, which contains monovalent and polyvalent impurity cations as impurity cations, is passed through the packed tower 30 which is a mixed bed of the first ion exchanger and the second ion exchanger, and the chelating resin (second ion exchanger) suitable for removing polyvalent impurity cations can efficiently remove the polyvalent impurity cations, while the cation exchange resin (first ion exchanger) can efficiently remove the monovalent impurity cations. In addition, the organic solvent purification system 1C of this embodiment can remove impurity cations in the organic solvent to be treated using only the packed tower 30 packed with a mixed bed of the first ion exchanger and the second ion exchanger without using multiple packed towers, so that the equipment can be made more compact and simple in configuration.

[0096] The mixing ratio of the mixed bed containing the first ion exchanger and the second ion exchanger according to the present invention is arbitrary as long as it does not impair the object of the present invention. For example, the ratio (volume) of the first ion exchanger to the second ion exchanger is 1:0.1-10.

[0097] The treatment conditions in the first to fourth embodiments of the organic solvent purification system of the present invention may be any conditions that can remove the target impurity cations, and can be appropriately determined depending on the type and amount of the first ion exchanger and the second ion exchanger, the type and amount of the organic solvent to be treated, the type and amount of the impurity cations to be treated (concentration), etc. The flow rate SV of the organic solvent to be treated is, for example, 0.1 to 50 h -1 , preferably 1 to 10 hours -1 The temperature of the organic solvent to be treated may be, for example, 0 to 50° C. The resin layer height (packed layer length) of the first ion exchanger and the second ion exchanger may be, for example, 10 to 300 cm, and preferably 20 to 200 cm.

[0098] Although the organic solvent purification system of the present invention has been described above using the drawings and the like, the present invention is not limited to the above-mentioned embodiment, and various modifications are possible within the scope of the gist of the present invention. Furthermore, matters not explicitly disclosed in the above-mentioned embodiment do not deviate from the scope of ordinary practice by a person skilled in the art, and values ​​that can be easily assumed by a person skilled in the art can be adopted.

[0099] For example, in the system for purifying an organic solvent of the present invention, the configuration of a single bed of the first ion exchanger, a single bed of the second ion exchanger, and a mixed bed containing the first ion exchanger and the second ion exchanger may be any configuration as long as it does not impair the object of the present invention.

[0100] When only a single bed of the first ion exchanger is used, one or more single beds of the first ion exchanger may be used. When two or more single beds of the first ion exchanger are combined, any number of single beds may be arranged in series and / or parallel.

[0101] When a single bed of the first ion exchanger and a single bed of the second ion exchanger are used in combination, one or more of each single bed may be used. When a single bed of the first ion exchanger and a single bed of the second ion exchanger are used in combination, any number of single beds may be used in series and / or parallel.

[0102] When only a mixed bed containing the first ion exchanger and the second ion exchanger is used, one or more mixed beds containing the first ion exchanger and the second ion exchanger may be used. When two or more mixed beds containing the first ion exchanger and the second ion exchanger are combined, any number of mixed beds may be arranged in series and / or parallel. When a single bed of the first ion exchanger, a single bed of the second ion exchanger, and a mixed bed containing the first ion exchanger and the second ion exchanger are used in combination, any number of single beds and / or mixed beds may be configured in series and / or parallel. EXAMPLES

[0103] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples. Note that the values ​​of various manufacturing conditions and evaluation results in the following examples have the meaning of preferred upper or lower limit values ​​in the embodiment of the present invention, and the preferred ranges have the meaning of the preferred upper or lower limit values ​​described above, and the preferred ranges may be ranges defined by the combination of the upper or lower limit values ​​and the values ​​of the following examples or the values ​​of the examples.

[0104] <1. Organic solvent to be treated and ion exchanger> Organic solvents A to C to be treated were prepared by adding simulated impurity cations (hereinafter, metal cations) to the organic solvent. (Organic solvent A to be treated) Organic solvent: 1-methoxy-2-propanol (Organic solvent B to be treated) Organic solvent: Methanol (Organic solvent C to be treated) Propylene glycol monomethyl ether acetate

[0105] The columns, chelating resins, and cation exchange resins used are as follows: Column: Teflon (registered trademark), inner diameter 16 mm, length 50 cm Chelate resin: N-methylglucamine type chelating resin (Muromac XMS-5119-FB, Muromachi Chemical Co., Ltd.) Cation exchange resin: Strongly acidic cation exchange resin (Muromac XSC-1191-H, manufactured by Muromachi Chemical Co., Ltd.)

[0106] <2. Evaluation and Results> [2-1. Experimental Example 1] The column was filled with 50 mL of chelating resin, and the organic solvent A to be treated was passed through the column at a flow rate of SV5h. -1The organic solvent A was passed through the column at a rate of 5 times the amount of resin per hour. When 10 BV of the organic solvent A was passed through the column, the organic solvent was sampled, and the content of metal cations in the purified organic solvent after passing through the column was measured using an ICP-MS (Agilent Technologies, Agilent 8900 ICP-QQQ). The results are shown in Table 1.

[0107] [Table 1]

[0108] As shown in Table 1, all of the added metal cations were removed except for alkali metal ions (Li, Na, K) and Pb. The concentrations of alkali metal ions (Li, Na, K) and Pb detected in the purified organic solvent were reduced to less than half of those contained in the treated organic solvent.

[0109] [2-2. Experimental Example 2] The same procedure as in Experimental Example 1 was repeated, except that a column packed with 50 mL of cation exchange resin was connected in series to the rear stage of a column packed with 50 mL of chelating resin. The results are shown in Table 2.

[0110] [Table 2]

[0111] As shown in Table 2, all of the added metal cations could be removed.

[0112] [2-3. Experimental Example 3] The same procedure as in Experimental Example 1 was repeated, except that a column packed with 50 mL of cation exchange resin was connected in series to the front stage of a column packed with 50 mL of chelating resin. The results are shown in Table 3.

[0113] [Table 3]

[0114] As shown in Table 3, all of the added metal cations could be removed.

[0115] [2-4. Experimental Example 4] The same procedure as in Experimental Example 1 was repeated, except that a column packed with 50 mL of cation exchange resin was used instead of the column packed with 50 mL of chelating resin. The results are shown in Table 4.

[0116] [Table 4]

[0117] As shown in Table 4, among the added metal cations, alkali metal ions (Li, Na, K, etc.) could be removed, but some metal cations such as Cr and Fe remained in greater amounts than in Experiments 1 to 3, in which the liquid was passed through a column packed with a chelating resin.

[0118] [2-5. Experimental Example 5] The same procedure as in Experimental Example 1 was repeated, except that the organic solvent B was used instead of the organic solvent A. The results are shown in Table 5.

[0119] [Table 5]

[0120] As shown in Table 5, all of the added metal cations were removed except for alkali metal ions (Li, Na, K), alkaline earth metals (Mg, Ca), and Pb. The alkaline earth metals (Mg, Ca) and Pb detected in the refined organic solvent were removed to less than half of the concentrations contained in the organic solvent to be treated. The concentrations of alkali metal ions (Li, Na, K) in the organic solvent to be treated and the refined organic solvent were almost the same.

[0121] [2-6. Experimental Example 6] The same procedure as in Experimental Example 1 was repeated, except that the organic solvent C was used instead of the organic solvent A. The results are shown in Table 6.

[0122] [Table 6]

[0123] As shown in Table 6, all of the added metal cations could be removed. [Explanation of symbols]

[0124] 1,1A,1B,1C Organic Solvent Purification System 10 Packed column (single bed of first ion exchanger) 20 Packed column (single bed of second ion exchanger) 30 Packed column (mixed bed of first ion exchanger and second ion exchanger)

Claims

1. The method includes a step of contacting an organic solvent to be treated, the organic solvent containing the organic solvent and the impurity cations, with a first ion exchanger to remove the impurity cations, The method for purifying an organic solvent, wherein the first ion exchanger contains a chelating resin having an N-methylglucamine group.

2. 2. The method for purifying an organic solvent according to claim 1, wherein the impurity cation is a polyvalent metal cation.

3. 2. The method for purifying an organic solvent according to claim 1, wherein the organic solvent is one or more organic solvents selected from the group consisting of methanol, ethanol, isopropanol, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate.

4. 2. The method for purifying an organic solvent according to claim 1, A method for purifying an organic solvent, comprising any one of the following treatments (A) to (C) using the first ion exchanger and a second ion exchanger containing a cation exchange resin: (A) A treatment in which the organic solvent to be treated containing the impurity cations is first contacted with a single bed of the first ion exchanger, and then with a single bed of the second ion exchanger. (B) A treatment in which the organic solvent to be treated containing the impurity cations is first contacted with a single bed of the second ion exchanger, and then with a single bed of the first ion exchanger. (C) contacting the organic solvent containing the impurity cations with a mixed bed of the first ion exchanger and the second ion exchanger;

5. 5. The method for purifying an organic solvent according to claim 4, wherein the second ion exchanger comprises a cation exchange resin having one or more functional groups selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, a phosphinic acid group, a phenoxide group, and an arsenous acid group.

6. A method for producing a purified organic solvent, comprising a step of using the method for purifying an organic solvent according to claim 1 .

7. 7. The method for producing a purified organic solvent according to claim 6, wherein the purified organic solvent is a solvent for cleaning semiconductor substrates.

8. a purification means having a first ion exchanger through which an organic solvent and an organic solvent to be treated containing impurity cations are passed, A system for purifying an organic solvent, characterized in that the first ion exchanger contains a chelating resin having an N-methylglucamine group.

9. The system for purifying an organic solvent according to claim 8, A system for purifying an organic solvent, comprising: a first ion exchanger and a second ion exchanger containing a cation exchange resin; and any one of the following purification means (A) to (C): (A) a purification means having a single bed of the first ion exchanger through which the organic solvent to be treated is passed, and a single bed of the second ion exchanger through which the treated liquid from the single bed of the first ion exchanger is passed. (B) a purification means having a single bed of the second ion exchanger through which the organic solvent to be treated is passed, and a single bed of the first ion exchanger through which the treated liquid of the single bed of the second ion exchanger is passed. (C) a purification means having a mixed bed containing the first ion exchanger and the second ion exchanger through which the organic solvent to be treated is passed;

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