Metal extracting agent, metal ion separation and recovery method using same, and compound

Abstract

A compound represented by formula (I), a metal extractant, and a method for separating and recovering metal ions using the metal extractant. In formula (I), R1 and R2 each represent a substituent having a molecular weight of 100 or more, and at least one of the substituents has a molecular weight of 160 or more. YP represents an oxygen atom or a sulfur atom. Z represents a hydroxyl group, a sulfanyl group, or a hydroxyaryl group. L represents a single bond, but when n is 2 or more, L sandwiched between two adjacent Ps represents a single bond or a linking group. And n is an integer of 1-6. Formula (I)

Description

Technical Field

[0001] This invention relates to a metal extractant for extracting metal ions present in an aqueous phase into an oil phase, a method for separating and recovering metal ions using the metal extractant, and a compound. Background Technology

[0002] Valuable metals such as precious metals and rare earth metals are essential elements for precision equipment, making their stable and high-purity supply a major challenge. These valuable metals are typically mined as mixtures with other metals, necessitating the separation and purification (high-purity) of the target valuable metal from these mixtures. Furthermore, the amount of valuable metals that can be mined is limited, thus technologies for recovering valuable metals from industrial waste without relying on mining are gaining importance. In particular, with the increasing prevalence of electric vehicles, the amount of waste from lithium-ion batteries (LiB) is increasing annually. LiB uses positive electrode active materials containing metals such as cobalt and nickel, and the demand for cobalt and nickel is expected to increase significantly. To address the increasing demand for valuable metals accompanying this trend, it is desirable not only to increase mining volume but also to establish technologies for recovering metals from waste LiB.

[0003] Wet extraction (solvent extraction) is used as a method for separating and purifying target valuable metals from mining mixtures and for recovering metals from waste. In wet extraction, an organic phase containing a metal extractant is contacted with an aqueous solution (aqueous phase) containing metal ions (referred to as metal ions) and mixed. The mixture is then allowed to stand, causing the two phases to separate. This allows the metal ions coordinated with the metal extractant to move (extract) into the organic phase. The organic phase is then removed, and the metal ions are back-extracted. Purification is then performed as needed, thereby enabling the separation and purification of the target metal and the recovery of (high-purity) metals.

[0004] As a metal extractant used in this wet extraction method, Patent Document 1 describes, for example, a metal extractant composed of a phenylphosphonic acid monoester with 4 to 6 branched carbon atoms and a total carbon number of 16 to 20. Furthermore, Patent Document 2 describes, as a metal extractant for a wet extraction method that involves multi-stage contact between an organic phase containing the metal extractant and an aqueous phase, an alkylphosphonic acid monoalkyl ester where both alkyl groups are alkyl groups with 8 to 10 carbon atoms (however, this excludes cases where both alkyl groups are the same alkyl group with 8 carbon atoms).

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-184503

[0008] Patent Document 2: Japanese Patent Publication No. 61-58531 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] Patent documents 1 and 2 describe the following: when the metal extractants described in patent documents 1 and 2 are used in wet extraction, specific metal ions present in the aqueous phase can be extracted and recovered into the oil phase. However, the selectivity (separation ability) of the extracted metal ions in any metal extractant is insufficient. In wet extraction, it is desirable to have a metal extractant with high selectivity that can selectively separate and extract specific metal ions from the aqueous phase.

[0011] Furthermore, if the metal extractants described in Patent Documents 1 and 2 are used in wet extraction methods, the separation of the aqueous and oil phases requires a long time after contact and mixing. As a result, the productivity (metal ion separation and recovery efficiency) of wet extraction is low, and it is not suitable for continuous separation and recovery processes. In particular, the metal extractant described in Patent Document 2 requires multi-stage contact between the aqueous and oil phases, which presents productivity problems. Therefore, there is a need for metal extractants with high-speed phase separation that can rapidly separate the aqueous and oil phases after contact and mixing.

[0012] However, no research was conducted in patent documents 1 and 2 on further improving the selectivity of metal ions and increasing the phase separation rate.

[0013] The objective of this invention is to provide a metal extractant capable of rapidly separating an aqueous phase and an oil phase containing metal ions while selectively extracting specific metal ions present in the aqueous phase into the oil phase, and a method for separating and recovering metal ions using the metal extractant. Furthermore, the objective of this invention is to provide a compound that can become a metal extractant exhibiting the aforementioned superior properties.

[0014] means for solving technical problems

[0015] The inventors conducted in-depth research on metal extractants used in wet extraction methods and discovered that by preparing them using a basic structure derived from phosphate compounds (-P(=Y)... P Z-:Y P As described below, compounds with at least one active hydrogen atom remaining in their basic structure and two substituents having a specific molecular weight can achieve both high-speed phase separation and improved selectivity (separation ability), and can solve the problem of reduced selectivity of extracted metal ions when the phase separation rate is increased, which is a common problem in conventional wet extraction methods.

[0016] Based on these insights, the present invention underwent further and repeated research to complete the present invention.

[0017] That is, the above problems can be solved by the following solutions.

[0018] <1> A metal extractant, which is a metal extractant that extracts metal ions present in the aqueous phase into the oil phase, and is represented by the following formula (I),

[0019] [Chemical Formula 1]

[0020]

[0021] In equation (I), R 1 and R 2 Each represents a substituent with a molecular weight of 100 or more, wherein at least one of the substituents has a molecular weight of 160 or more.

[0022] Y P Represents oxygen or sulfur atoms.

[0023] Z represents hydroxyl, thioalkyl, or hydroxyaryl.

[0024] L represents a single bond; however, when n is 2 or more, L sandwiched between two adjacent P bonds represents a single bond or a linker.

[0025] n is an integer from 1 to 6.

[0026] <2> According to the metal extractant described in <1>, wherein R 1 and R 2 At least one of them is a substituent containing any one of nitrogen, oxygen and sulfur atoms.

[0027] <3> The metal extractant according to <1> or <2>, wherein n is 1.

[0028] <4> The metal extractant according to any one of <1> to <3>, wherein R 1 and R 2 At least one of them is a substituent with a branched structure.

[0029] <5> The metal extractant according to any one of <1> to <4>, wherein R 1 and R 2 At least one of them is a substituent containing a hydrocarbon group having 3 or more branched carbon atoms or a substituent containing a hydrocarbon group having 9 or more carbon atoms.

[0030] <6> The metal extractant according to any one of <1> to <5>, wherein R 1 and R 2 At least one of them is a substituent containing a hydrocarbon group having one or more branched carbon atoms and having a carbon number of nine or more.

[0031] <7> The metal extractant according to any one of <1> to <6>, wherein R 1 and R 2 At least one of them is a substituent containing a ring structure.

[0032] <8> The metal extractant according to any one of <1> to <7>, wherein the metal ion is an ion of a metal element belonging to Group 1 to Group 14 of the periodic table.

[0033] <9> The metal extractant according to any one of <1> to <8> is used to extract and separate two or more metal ions belonging to different groups in the periodic table.

[0034] <10> A method for separating and recovering metal ions, wherein an aqueous phase containing multiple metal ions and an oil phase containing any one of <1> to <9> are mixed.

[0035] <11> A compound represented by the following formula (I).

[0036] [Chemical Formula 2]

[0037]

[0038] In equation (I), R 1 and R 2 Each represents a substituent with a molecular weight of 100 or more, wherein at least one of the substituents has a molecular weight of 160 or more. R 1 and R 2 At least one of them represents a substituent with a branched structure.

[0039] Y P Represents oxygen or sulfur atoms.

[0040] Z represents hydroxyl, thioalkyl, or hydroxyaryl.

[0041] L represents a single bond; however, when n is 2 or more, L sandwiched between two adjacent P bonds represents a single bond or a linker.

[0042] n is an integer from 1 to 6.

[0043] Invention Effects

[0044] This invention provides a metal extractant capable of rapidly separating an aqueous phase and an oil phase containing metal ions while selectively extracting specific metal ions present in the aqueous phase into the oil phase, and a method for separating and recovering metal ions using the metal extractant. Furthermore, this invention provides a compound that can be a metal extractant exhibiting the aforementioned superior properties.

[0045] The above-described features and other features and advantages of the present invention will become more apparent from the accompanying drawings and from the following description. Attached Figure Description

[0046] Figure 1 It is the compound E-1 synthesized in the examples. 1 H-NMR spectrum. Detailed Implementation

[0047] In this invention, when numerical ranges are shown to describe the content, physical properties, etc. of a component, and the upper and lower limits of the numerical range are described separately, any appropriate combination of the upper and lower limits can be used to define a specific numerical range. On the other hand, when multiple numerical ranges represented by "~" are defined and described, the upper and lower limits forming the numerical range are not limited to a specific combination before and after "~" as a specific numerical range; a numerical range can be defined as an appropriate combination of the upper and lower limits of each numerical range. Furthermore, in this invention, the numerical range represented by "~" refers to a range that includes the values ​​before and after "~" as both the lower and upper limits.

[0048] In this invention, the designation of a compound (e.g., when referred to as a compound by appending a compound at the end) means that in addition to the compound itself, it also includes its salt and its ions. Furthermore, it means that, to a extent that it does not impair the effects of this invention, it includes derivatives that modify a portion by introducing substituents or the like.

[0049] In this invention, the term "substituent, linking group, etc." (hereinafter referred to as "substituent, etc.") that is not explicitly stated as substituted or unsubstituted refers to the possibility of having suitable substituents in the group. Therefore, in this invention, even when simply stated as a YYY group, the YYY group includes both the form without substituents and the form with substituents. This also applies to compounds that are not explicitly stated as substituted or unsubstituted. Preferred substituents include, for example, groups selected from the substituents GZ described later.

[0050] In this invention, when multiple substituents, etc., are represented by specific symbols, or when multiple substituents, etc., are defined simultaneously or selectively, it means that each substituent, etc., can be the same as or different from each other. Furthermore, even without specific explanation, when multiple substituents, etc., are adjacent, it means that they can connect or fused together to form a ring.

[0051] In addition, in this specification, "metallic elements belonging to different groups in the periodic table" are sometimes referred to as "different group metal elements", and in particular, "different group metal elements in the same period of the periodic table" are referred to as "different group metal elements in the same period". Furthermore, "ions of different group metal elements" and "ions of different group metal elements in the same period" are sometimes referred to as "different group metal ions" and "different group metal ions in the same period", respectively.

[0052] In this invention, unless otherwise specified, "ppm" indicating content, etc., is a quality standard and means "mass ppm".

[0053] [Metal Extractant]

[0054] The metal extractant of the present invention comprises a compound represented by formula (I) as described later, and may appropriately contain other components without impairing the effectiveness of the present invention. Furthermore, in addition to the compound represented by formula (I), the metal extractant of the present invention may also contain other compounds that function as metal ion extractants (other metal extractants). However, as described later, the compound represented by formula (I) exhibits the aforementioned superior properties as a metal extractant, and therefore it is preferable to contain only the compound represented by formula (I). In the present invention, the metal extractant of the present invention containing only the compound represented by formula (I) means containing only the compound represented by formula (I) and containing other metal extractants in an amount of 10% by mass or less relative to the total amount of the compound represented by formula (I).

[0055] Furthermore, the form of the metal extractant and the compound represented by formula (I) of the present invention is not particularly limited, and can be in the form of solid such as powder or granules, or in the form of liquid (solution) dissolved in the organic solvent described later.

[0056] The metal extractant of the present invention exhibits the function of extracting metal ions present in the aqueous phase into the oil phase, and is particularly preferred for use in wet extraction methods. When the metal extractant of the present invention is used in a wet extraction method, specific metal ions present in the aqueous phase can be extracted into the oil phase with high selectivity (preferably high recovery rate (high extraction rate)). In particular, this metal extractant can extract specific metal ions from a variety of metal ions present in the aqueous phase into the oil phase with high selectivity (preferably high recovery rate).

[0057] In this invention, the metal ion that can be extracted from the oil phase among multiple metal ions present in the aqueous phase is ideally a single specific metal ion, but sometimes it is two or more metal ions. Even in the case of two or more metal ions, one of the metal ions can be extracted (preferably with high recovery) into the oil phase with high selectivity (preferably with high recovery) relative to the other metal ions (including the metal ions extracted into the oil phase). For example, as ions of valuable metal elements, two or more heterogeneous metal ions, such as two or more metal ions belonging to Groups 1 to 14 of the periodic table (preferably two or more heterogeneous metal ions, especially heterogeneous metal ions of the same period, i.e., cobalt ions and nickel ions), can be extracted into the oil phase with high selectivity (preferably with high recovery) of one of the metal ions.

[0058] Because dissimilar metal ions within the same period exhibit similar physical and chemical behaviors, it is not easy to selectively separate and recover any one of them. However, in this invention, which uses a compound represented by formula (I) as a metal extractant, it is possible to extract both dissimilar metal ions within the same period with high selectivity (preferably high recovery rate) while simultaneously recovering one of the metal ions, particularly those belonging to Group 9 (especially cobalt ions) and Group 10 (especially nickel ions), which have become increasingly important due to the rapid proliferation of lithium-ion batteries in recent years. Therefore, this invention can greatly contribute to the further popularization of electric vehicles and, consequently, the construction of a sustainable society.

[0059] In this invention, the ability to selectively extract metal ions means being able to extract only one specific metal ion from a plurality of metal ions present in the aqueous phase. Furthermore, when extracting two or more metal ions in the oil phase, the ability to selectively extract metal ions means that, among the two or more metal ions extracted, the ratio of the extraction amount of the specific metal ion (usually one) as the extraction target to the total extraction amount of the other metal ions [(extraction amount of the specific metal ion) / (total extraction amount of the other metal ions)] can be extracted and separated from the other metal ions at a ratio (separation ability, selectivity) of 3.0 or higher. The aforementioned ratio (selectivity) is preferably 4.0 or higher, more preferably 5.0 or higher, and even more preferably 6.0 or higher. As an upper limit, there is no particular limitation; for example, it can be set to 50.

[0060] Furthermore, in this invention, high recovery rate of metal ions means that, regarding the metal ions extracted at the maximum extraction rate (the specific metal ion targeted for extraction), the ratio of the extraction amount of that metal ion in the oil phase to its content in the aqueous phase (before extraction) [(extraction amount of metal ions in the oil phase) / (content of that metal ion in the aqueous phase)] can be extracted at a rate of 60% or more. This ratio (recovery rate) is preferably 80% or more, more preferably 90% or more. There is no particular upper limit; ideally, the total amount of that metal ion present in the aqueous phase (100%) is present, for example, preferably 99% or less, and can also be set to 95% or less or 90% or less. The specific extraction amount, while also depending on the content of the metal ions present in the aqueous phase, can be set to, for example, 30,000 ppm by mass or less, preferably 20,000 ppm by mass or less.

[0061] In this invention, the time required for rapid liquid-phase separation (phase separation) after the aqueous and oil phases have come into contact and mixed is not uniquely determined based on the content of metal ions or metal extractants, the volume of the aqueous and oil layers, mixing conditions, etc. Rapid liquid-phase separation of the aqueous and oil phases means, for example, under the conditions described in the embodiments below, that the two phases have separated to a state where the phase interface can be visually confirmed after 5 minutes (after 5 minutes) following the cessation of mixing. In this invention, the time required until the liquid-phase separation of the two phases is complete (to a state where the phase interface can be visually confirmed) after contact and mixing of the aqueous and oil phases is called the phase separation time, and the rate at which the two phases separate after contact and mixing is called the phase separation rate.

[0062] (Compounds represented by formula (I))

[0063] The metal extractant of the present invention is composed of a compound having a chemical structure represented by the following formula (I) (sometimes referred to as the compound of the present invention). As described above, this compound exhibits excellent properties as a metal extractant.

[0064] [Chemical Formula 3]

[0065]

[0066] In equation (I), R 1 and R 2 These represent substituents with a molecular weight of 100 or more, wherein at least one of the substituents has a molecular weight of 160 or more. That is, R 1 and R 2 These are substituents with a molecular weight of 100 or more, wherein at least one of the substituents has a molecular weight of 160 or more. The basic structure in formula (I) above is "-P(=Y". P )Z-"(YP (And Z as described below.) Two substituents R with specific molecular weights are bonded to it. 1 and R 2 The compound became a metal extractant that exhibited the aforementioned excellent effects.

[0067] Examples of compounds represented by formula (I) having the above-described basic structure include compounds having 1 to 6 phosphate groups, phosphonic acid groups, hypophosphonic acid groups, and acid groups in which at least one oxygen atom of these acid groups is replaced by a sulfur atom. For example, phosphate ester compounds (R) are examples of compounds where n is 1 in formula (I). 1 OP(=O)(Z)-OR 2 ), phosphonate compounds (R 1 -P(=O)(Z)-OR 2 R 1 OP(=O)(Z)-R 2 ) or phosphonic acid compounds (R 1 -P(=O)(Z)-R 2 Phosphoric acid compounds, such as those containing at least one oxygen atom in each of the aforementioned phosphoric acid compounds, and thiophosphate compounds, which convert at least one oxygen atom in each of the aforementioned phosphoric acid compounds into a sulfur atom. Furthermore, the "Z" in each of the aforementioned compounds has the same meaning as Z in formula (I). From the viewpoint of achieving a higher level of balance between the selectivity of the metal extractant and the phase separation rate, compounds with n=1 represented by formula (I) are preferably phosphoric acid compounds, more preferably phosphate ester compounds, phosphonate compounds, and even more preferably phosphonate compounds, especially phosphonic acid monoester compounds.

[0068] Can be used as R 1 and R 2 All substituents are used with a molecular weight of 100 or higher. Furthermore, it can be used as R... 1 and R 2 The molecular weight of at least one of the substituents is set to 160 or higher. It can be used as R. 1 Substituents and can be used as R 2 The substituents all have a molecular weight of 100 or more, and at least one of them has a molecular weight of 160 or more, thus the compound represented by the above formula (I) becomes a metal extractant that exhibits high selectivity even with a fast phase separation rate.

[0069] From the perspective of the selectivity and phase separation rate of metal extractants, it can be used as R 1 and R 2 The molecular weight of the substituent is preferably 120 or more, more preferably 160 or more, and even more preferably 200 or more. On the other hand, there is no particular upper limit to the molecular weight of the substituent, and it can be appropriately determined. For example, it can be set to 400 or less, preferably 350 or less.

[0070] From the perspective of achieving a high level of balance between the selectivity of metal extractants and the phase separation rate, it can be used as R 1 and R 2 The molecular weight of the two substituents is preferably 160 or higher. From the viewpoint of achieving a higher level of balance between the selectivity of the metal extractant and the phase separation rate, it can be used as R... 1 and R 2 The substituents with a molecular weight of 160 or more preferably have a molecular weight of 200 or more, more preferably 220 or more, and even more preferably 240 or more. There is no particular upper limit on the molecular weight of the substituents with a molecular weight of 160 or more, and they can be configured to be used as R. 1 and R 2 The molecular weight of the substituents is limited to the aforementioned upper limit. In the case where it can be used as R... 1 and R 2 When all substituents have a molecular weight of 160 or more, it is preferable that at least one of the substituents has the above molecular weight.

[0071] In this invention, the molecular weight of a substituent refers to the total atomic weight of the atoms constituting the substituent. However, when the substituent has a polymer chain in its structure, it is set as the number-average molecular weight converted from standard polystyrene based on gel permeation chromatography (GPC) described later.

[0072] Can be used as R 1 and R 2 As long as the substituents meet the above molecular weight requirements, the total number of carbon atoms constituting each substituent is not particularly limited and can be appropriately determined. For example, from the viewpoint of the selectivity and phase separation rate of metal extractants, it can be used as R 1 and R 2 The total number of carbon atoms in the substituents (hereinafter simply referred to as the number of carbon atoms) is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and particularly preferably 14 or more. On the other hand, there is no particular limitation on the upper limit of the number of carbon atoms, and it can be appropriately determined. For example, it can be set to 30 or less, and preferably 24 or less.

[0073] From the perspective of achieving a higher level of balance between the selectivity of metal extractants and the phase separation rate, it can be used as R 1 and R 2 The substituent with a molecular weight of 160 or more preferably has 12 or more carbon atoms, more preferably 14 or more, even more preferably 15 or more, and particularly preferably 16 or more. There is no particular upper limit on the number of carbon atoms in the substituent with a molecular weight of 160 or more, and it can be configured to be used as R. 1 and R 2 The above-mentioned upper limit for the number of carbon atoms of the substituents.

[0074] As can be used as R 1 and R 2 The substituents are not particularly limited, and various substituents and groups formed by combinations of substituents can be cited. In this invention, the aforementioned "various substituents" refer to groups that are individually R 1 and R 2 The term "group formed by combining substituents" refers to a substituent formed by combining multiple substituents. Furthermore, to clearly distinguish between the aforementioned "various substituents" and the aforementioned "group formed by combining substituents," for convenience, the aforementioned "various substituents" are sometimes referred to as "individual substituents," and the aforementioned "group formed by combining substituents" is referred to as "complex substituents." Additionally, complex substituents are formed by removing a desired number of hydrogen atoms from the individual substituents constituting them, thereby bonding multiple individual substituents.

[0075] In complex substituents, there are no particular restrictions on the position at which a specific substituent is replaced by another substituent, and these positions can be appropriately determined. For example, when a phenyl group is replaced by another substituent, the substitution position relative to the bonding position of the phenyl group can be any position from the 2nd to the 4th position.

[0076] In this invention, it can be used as R 1 and R 2 Substituents should be interpreted as individual substituents whenever possible. For example, 2-ethylhexyl can also be interpreted as a complex substituent of ethyl-substituted hexyl, but as a branched alkyl group. Furthermore, hexyloxy can also be interpreted as a complex substituent formed by combining a hexyl group and an oxygen atom, but as an alkoxy group.

[0077] Can be used as R 1 and R 2 The substituents (including single substituents and complex substituents) can be hydrocarbon groups consisting only of carbon and hydrogen atoms, or they can be heteroatom-containing substituents containing at least one type of heteroatom such as nitrogen, oxygen, or sulfur. It can be used as R 1 and R 2 At least one of the substituents is preferably a heteroatom-containing substituent. The heteroatom-containing substituent preferably contains an oxygen atom or a sulfur atom as a heteroatom, and more preferably contains an oxygen atom. Furthermore, the number of heteroatoms contained in the heteroatom-containing substituent is not particularly limited, and can be 1 to 4, preferably 1. In the heteroatom-containing substituent, the heteroatom can be present in any substituent, for example, it can be present inside the atomic chain constituting the substituent or at its end. In this invention, it is preferred that one heteroatom is present at the end of the atomic chain constituting the substituent and is bonded to P in the above formula (I).

[0078] There are no particular limitations on the substituents containing heteroatoms. Examples include individual substituents such as alkoxy, aryloxy, heterocyclic oxy, alkathio, arylthio, and heterocyclic thio, or complex substituents such as groups formed by combining these individual substituents with aryl groups (including substituents with ring structures).

[0079] As can be used as R 1 and R 2 The individual substituents are not particularly limited, and suitable substituents can be cited, for example, groups selected from the substituents GZ described below (however, the number of carbon atoms and molecular weight are not based on the number of carbon atoms and molecular weight of the substituent GZ, but on the aforementioned number of carbon atoms and molecular weight). Among them, alkyl, alkenyl, alkynyl, aryl, and other hydrocarbon groups, heterocyclic groups, alkoxy, aryloxy, heterocyclic alkoxy, alkylthio, arylthio, heterocyclic thio, amino, etc. are preferred. From the viewpoint of the selectivity of the metal extractant and the phase separation rate, alkyl, alkoxy, and alkoxy are more preferred, and alkyl or alkoxy are even more preferred.

[0080] Alkyl, alkenyl, and alkynyl groups, which can be used as individual substituents, can be straight-chain, branched-chain, or cyclic-chain, but branched-chain is preferred from the viewpoint of achieving a higher level of selectivity for metal extractants and phase separation rate. The molecular weight and number of carbon atoms of alkyl, alkenyl, and alkynyl groups all meet the above-mentioned ranges.

[0081] The aryl, heterocyclic, aryloxy, heterocyclic oxy, arylthio, heterocyclic thio, and amino groups that can be used as individual substituents are the same as the corresponding groups in the substituent GZ described later.

[0082] The alkyl groups that can be used as individual substituents, such as alkoxy and alkylthio groups, are the same as those that can be used as individual substituents.

[0083] As can be used as R 1 and R 2 The complex substituent is not particularly limited, and examples include (single) substituents, such as a group composed of multiple substituents selected from substituents GZ. The number of individual substituents constituting the complex substituent is not particularly limited, and can be set to 2 to 6, preferably 2 to 4.

[0084] Examples of complex substituents include groups formed by combining hydrocarbon groups (groups formed by combining alkyl, alkenyl, or alkynyl groups with aryl groups), groups formed by combining alkoxy or alkylthio groups with aryl groups, and groups formed by combining alkyl, alkenyl, or alkynyl groups with amino groups. Furthermore, when the complex substituent contains an oxygen atom or sulfur atom bonded to an alkyl group, the oxygen and sulfur atoms are interpreted as atoms derived from the alkoxy or alkylthio groups. For example, the complex substituent "alkyl-oxygen-phenyl-" in compounds E-4 and E-5 synthesized in the examples is interpreted as a group formed by combining an alkoxy group and a phenyl group, not as a group formed by combining an alkyl group and a phenoxy group, and not as a group formed by combining an alkyl group, an oxygen atom, and a phenyl group. The same interpretation applies to cases where the complex substituent contains an oxygen atom bonded to an alkenyl or alkynyl group.

[0085] From the viewpoint of achieving a higher level of selectivity and phase separation rate for the metal extractant, substituents containing ring structures are preferred as complex substituents. There are no particular limitations on the ring structure contained in the complex substituent; for example, ring structures derived from cycloalkyl, aryl, or heterocyclic groups can be cited. Ring structures derived from aryl or aromatic heterocyclic groups are preferred, and ring structures derived from aryl groups are more preferred from the viewpoint of metal extractant selectivity and phase separation rate. Specifically, as complex substituents containing ring structures, groups formed by combining alkyl and aryl groups, groups formed by combining alkoxy or alkylthio groups and aryl groups, etc., are preferred, alkoxyaryl groups are more preferred, and alkoxyphenyl groups are even more preferred.

[0086] As can be used as R 1 and R 2 In the above, from the viewpoint of the selectivity of the metal extractant and the phase separation rate, it is preferred to have individual substituents of alkyl, alkoxy, or alkylthio groups, or composite substituents containing a ring structure formed by combining alkoxy or alkylthio groups with aryl groups.

[0087] Among the preferred substituents mentioned above, from the viewpoint of the selectivity of the metal extractant and the phase separation rate, alkoxy, alkylthio, and complex substituents containing ring structures are preferably substituents with a molecular weight of 160 or more.

[0088] As can be used as R 1 Substituents and those that can be used as R 2 The combination of substituents is not particularly limited, and any appropriate combination can be used as R. 1 and R 2 The above-mentioned substituents are mutually substituents.

[0089] For example, there are no particular restrictions on the molecular structure of the substituents, but from the perspective of the selectivity and phase separation rate of metal extractants, they can be used as R 1 and R 2The substituents are preferably combinations of substituents having branched structures (at least one of which is a combination of substituents having branched structures), more preferably combinations of substituents having branched structures with each other, or combinations of substituents having branched structures with substituents containing ring structures (especially complex substituents). Here, there is no particular limitation on the substituents having branched structures. Examples of substituents include alkyl, alkenyl, alkynyl, and other hydrocarbon groups, single substituents containing hydrocarbon groups, or complex substituents. Preferably, there are single substituents such as alkyl, alkoxy, and arylthio groups, or complex substituents such as groups formed by combining alkoxy or alkoxy groups with aryl groups. More preferably, there are alkyl, alkoxy, or groups formed by combining alkoxy and aryl groups.

[0090] In this invention, the substituents with branched structures do not have to be substituents with a molecular weight of 160 or more or substituents with 12 or more carbon atoms. However, from the viewpoint of the selectivity of the metal extractant and the phase separation rate, substituents with a molecular weight of 160 or more or substituents with 12 or more carbon atoms are preferred.

[0091] Furthermore, there are no particular restrictions on the types of substituents that can be used as R. 1 and R 2 From the viewpoint of metal extractant selectivity and phase separation rate, the combination of substituents is preferably a combination of individual substituents or a combination of individual substituents and complex substituents.

[0092] In combinations of individual substituents, the same type of substituents can be combined, or different types of substituents can be combined. Examples of combinations of the same substituents include combinations of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, or alkylthio groups. In these combinations of the same substituents, the carbon chains of the individual substituents can be the same or different, but are preferably branched. Furthermore, the number of carbon atoms in the individual substituents can be the same or different.

[0093] On the other hand, as combinations of different substituents, combinations where one substituent is an alkoxy or alkathioyl group are preferred. From the viewpoint of metal extractant selectivity and phase separation rate, combinations of alkyl, alkenyl, or alkynyl groups with alkoxy or alkathioyl groups are more preferred, and combinations of alkyl groups with alkoxy groups are even more preferred. In the above-mentioned combinations of different substituents, the carbon chain of the alkyl, alkenyl, or alkynyl group may be the same as or different from the carbon chain of the alkyl group constituting the alkoxy or alkathioyl group, but both are preferably branched. Furthermore, the number of carbon atoms of the alkyl, alkenyl, or alkynyl group may be the same as or different from the number of carbon atoms of the alkyl group constituting the alkoxy or alkathioyl group. In the above-mentioned preferred combinations of different substituents, from the viewpoint of being able to balance metal extractant selectivity and phase separation rate at a higher level, alkoxy and alkathioyl groups preferably have a larger molecular weight and number of carbon atoms than alkyl, alkenyl, and alkynyl groups, and more preferably substituents with a molecular weight of 160 or more.

[0094] From the viewpoint of selectivity and phase separation rate of metal extractants, combinations of alkyl, alkenyl, alkynyl, alkoxy or alkylthio groups with complex substituents containing a ring structure are preferred as individual substituents and combinations of complex substituents. More preferably, combinations of alkyl, alkoxy or alkylthio groups with complex substituents formed by combining alkoxy and aryl groups are preferred.

[0095] As can be used as R 1 Substituents and those that can be used as R 2 The combination of substituents, in the above combinations, is particularly preferred to be the combination of alkoxy groups with each other, the combination of alkyl and alkoxy groups, and the combination of alkoxy and alkoxyaryl groups.

[0096] In the compounds represented by formula (I), it can be used as R. 1 and R 2 The substituents can be appropriately selected from the above-mentioned substituents, but considering the molecular structure and carbon number of the substituents, R is preferred from the viewpoint of achieving a high level of both selectivity of the metal extractant and phase separation rate. 1 and R 2 At least one of them is a substituent containing a hydrocarbon group having 3 or more branched carbon atoms or a substituent containing a hydrocarbon group having 9 or more carbon atoms, more preferably R 1 and R 2 All of these are substituents containing hydrocarbon groups with 3 or more branched carbon atoms or substituents containing hydrocarbon groups with 9 or more carbon atoms.

[0097] In this invention, substituents containing specific groups or ring structures include substituents consisting only of specific groups or ring structures and substituents consisting of specific groups or ring structures and other groups, atoms, or structures (details will be described later). For example, substituents containing hydrocarbon groups include substituents consisting only of hydrocarbon groups (the hydrocarbon group itself) and hydroxyl groups consisting of the hydrocarbon group and, for example, an oxygen atom.

[0098] There is no particular limitation on the hydrocarbon group having three or more branched carbon atoms. Examples of such groups include alkyl, alkenyl, or alkynyl groups with three or more branched carbon atoms (tertiary carbon atoms). The number of branched carbon atoms in the hydrocarbon group is not particularly limited as long as it is three or more; for example, it can be three to eight. From the viewpoint of selectivity and phase separation rate of the metal extractant, three to six is ​​preferred, and four to six is ​​more preferred. There are no particular limitations on the molecular weight and number of carbon atoms of the hydrocarbon group having three or more branched carbon atoms, and it can be appropriately selected within the above range. However, a molecular weight of 160 or more and a number of carbon atoms of 12 or more are preferred. As for the hydrocarbon group having three or more branched carbon atoms, alkyl groups with three or more branched carbon atoms are preferred, such as 2,5,7,7-tetramethyloctane and 2-(1,3,3-trimethyl-1-butyl)-5,7,7-trimethyl-octane.

[0099] There is no particular limitation on the hydrocarbon group having 9 or more carbon atoms. Among the above-mentioned hydrocarbon groups, alkyl, alkenyl, or alkynyl groups are preferred, and alkyl groups are more preferred. There is no particular limitation on the molecular weight of the hydrocarbon group having 9 or more carbon atoms as long as it is 127 or more, and it is preferable to select one that is suitable within the above-mentioned range.

[0100] The hydrocarbon group with 9 or more carbon atoms can be straight-chain or branched, but branched is preferred. When the hydrocarbon group with 9 or more carbon atoms is branched, there is no particular restriction as long as the number of branched carbon atoms is 1 or more; examples include 1, 2, or 3 or more. In the case of 3 or more branched carbon atoms, from the viewpoint of selectivity of the metal extractant and phase separation rate, the number of branched carbon atoms is preferably the same as the number of branched carbon atoms in the hydrocarbon group having 3 or more of the aforementioned branched carbon atoms.

[0101] As a hydrocarbon group having 9 or more carbon atoms, an alkyl group having 9 or more carbon atoms is preferred, and a branched alkyl group having 9 or more carbon atoms is more preferred. Examples of straight-chain alkyl groups having 9 or more carbon atoms include n-nonyl, n-decyl, n-dodecyl, n-tetradecyl, and n-hexadecyl. Examples of alkyl groups having 9 or more carbon atoms and having 1 or 2 branched carbon atoms include 1-ethyl-1-methylhexane, 8-methylnonane, 2-butyloctane, 2-hexyldecane, 2-ethyldecane, 2-octyldecane, 2-hexyldodecane, 2-octyldodecane, and 2-decyltetradecane. Examples of alkyl groups having 9 or more carbon atoms and having 3 or more branched carbon atoms include 2-(1,3,3-trimethyl-1-butyl)-5,7,7-trimethyl-octane.

[0102] There are no particular limitations on the atoms or groups other than the hydrocarbon group that constitute the substituent containing the aforementioned hydrocarbon group. Examples include groups selected from the substituents GZ described below (substituents other than hydrocarbon groups) and the aforementioned heteroatoms. Among these, groups containing the aforementioned hydrocarbon group and an oxygen atom or a sulfur atom are preferred. Specifically, examples include alkoxy groups and alkathio groups.

[0103] In this approach, as can be used as R 1 Substituents and those that can be used as R 2 The combination of substituents is not particularly limited, as long as any one of the substituents is a hydrocarbon group containing 3 or more branched carbon atoms or a hydrocarbon group containing 9 or more carbon atoms, and these substituents can be combined with substances that are not suitable for use as R. 1 and R 2 The substituents mentioned above include suitable combinations of substituents comprising either a hydrocarbon group having three or more branched carbon atoms or a hydrocarbon group having nine or more carbon atoms. Substituents that do not belong to any of the above categories are not uniquely determined by substituents comprising a hydrocarbon group having three or more branched carbon atoms or substituents comprising a hydrocarbon group having nine or more carbon atoms; for example, straight-chain alkyl groups having eight carbon atoms can be cited.

[0104] In formula (I), Y P It represents an oxygen atom or a sulfur atom, preferably an oxygen atom.

[0105] In formula (I), Z represents hydroxyl, thioalkyl (mercapto) or hydroxyaryl. As a preferred first option for the group that can be used as Z, hydroxyl or thioalkyl is preferred, and hydroxyl is more preferred. On the other hand, as a preferred second option for the group that can be used as Z, hydroxyl or hydroxyaryl is preferred.

[0106] As the hydroxyaryl group that can be used as Z, any aryl group having at least one hydroxyl group is acceptable. Examples of aryl groups include the aryl group in the substituent GZ described later, with phenyl being preferred. The number of hydroxyl groups introduced into the aryl group is not particularly limited and can be from 1 to 4, preferably 1 or 2. The position of the aryl group into which the hydroxyl group is introduced is not particularly limited and can be appropriately set relative to the bonding position of the aryl group. For example, in the case of a phenyl group, it can be any one of the positions 2 to 4 relative to the bonding position, with position 2 being preferred. Examples of hydroxyaryl groups include 2-, 3-, or 4-hydroxyphenyl, dihydroxyphenyl, trihydroxyphenyl, tetrahydroxyphenyl, etc. From the viewpoint of selectivity of the metal extractant and phase separation rate, 2-, 3-, or 4-hydroxyphenyl is preferred.

[0107] Each group that can be used as Z can form a salt. There are no particular limitations on the cations that can form the salt; examples include metal cations, especially group 1 or 2 metal cations, and organic cations. There are no particular limitations on organic cations; examples include ammonium cations and alkylammonium cations.

[0108] In equation (I), L represents a single bond. However, when n is 2 or more, L sandwiched between two adjacent P bonds represents a single bond or a linker.

[0109] There are no particular limitations on the linker that can be used as L, and examples include alkylene groups (preferably 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 4), alkenyl groups (preferably 2 to 6 carbon atoms, more preferably 2 to 3), aryl groups (preferably 6 to 24 carbon atoms, more preferably 6 to 10), oxygen atoms, sulfur atoms, and imino groups (-NR). N -:R N This refers to a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, or a carbonyl group, or a group related to combinations thereof. As a linking group, preferably an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, or an imino group, or a group related to combinations thereof, more preferably an alkylene group. Here, the alkylene group and the alkenyl group can be any of a straight chain, a branched chain, or a cyclic chain, but are preferably straight chains or branched chains.

[0110] The number of groups, linkers, or atoms in the combination is not particularly limited; for example, it can be 2 to 15, preferably 2 to 10, and more preferably 2 to 5. Furthermore, the number of types of groups, linkers, or atoms in the combination is not particularly limited; for example, it can be 2 or more, preferably 2 or 3.

[0111] The number of connecting atoms in the aforementioned linking group is not particularly limited, but is preferably 15 or less, more preferably 10 or less, even more preferably 6 or less, and particularly preferably 4 or less. The lower limit is 1 or more. The aforementioned number of connecting atoms refers to the minimum number of atoms connecting two adjacent P atoms. The number of atoms constituting the aforementioned linking group (the number of constituting atoms) is not particularly limited, for example, it can be set to 3 to 30, preferably 3 to 20, and more preferably 3 to 10. For example, in the case where the linking group is -CH2-CH2-, the number of atoms constituting the molecular structure is 6, but the number of connecting atoms is 2.

[0112] In addition, when the compound represented by formula (I) has two or more linking groups, at least one linking group is sufficient to satisfy the above-mentioned number of linking atoms and number of constituent atoms, and preferably all linking groups satisfy the above-mentioned number of linking atoms and number of constituent atoms.

[0113] In equation (I), n is an integer from 1 to 6.

[0114] As a preferred first option for n, n is preferably an integer from 1 to 3.

[0115] As a second preferred method for n, n is preferably an integer from 1 to 3 to 6.

[0116] In both the first and second methods, n is more preferably 1.

[0117] Additionally, when n is an integer from 2 to 6, n Y P Z and L can be the same or different.

[0118] The compound represented by formula (I) can convert R in the formula 1 and R 2 Y P The symbols are formed by appropriately combining Z, L, and n, preferably by combining preferred symbols of each symbol with each other.

[0119] However, while the compound represented by formula (I) can be a basic compound, from the viewpoint of exhibiting excellent selectivity and high phase separation rate as a metal extractant, it is preferable to be an acidic compound having at least one active hydrogen atom; that is, the compound represented by formula (I) is equivalent to an acidic metal extractant. Examples of active hydrogen atoms in the compound include hydroxyl groups (including phenolic hydroxyl groups) and hydrogen atoms in thioalkyl groups. The active hydrogen atom can be present in R... 1 R 2It may be present in any of L, but preferably in Z above. The number of hydroxyl groups present in the compound is only one or more, and can be from one to four, preferably one or two. In the compound represented by formula (I), the group containing the active hydrogen atom can form a salt, and the active hydrogen atom is converted into a cation. There are no particular limitations on such cations, and examples of the cations described in Z above can be cited.

[0120] The compound represented by formula (I) can act as a polydentate ligand for specific metal ions present in the aqueous phase (the metal ions to be extracted), but from the viewpoint of selectivity and phase separation rate, it is preferred to act as a monodentate ligand.

[0121] The molecular weight of the compound represented by formula (I) is not particularly limited; for example, it can be set to 350 to 50,000, but from the viewpoint of solubility in the oil phase, it is preferably 400 to 10,000, and more preferably 500 to 1,000. In this invention, when the compound represented by formula (I) has a polymer chain, its molecular weight, unless otherwise specified, refers to the number-average molecular weight converted from standard polystyrene based on gel permeation chromatography (GPC).

[0122] -Measurement of molecular weight-

[0123] The method for determining the molecular weight of oligomers is generally set as the value determined by the method described in condition 1 or condition 2 (preferred). However, a suitable eluent can be selected and used according to the type of oligomer.

[0124] (Condition 1)

[0125] String: Connects 2 TOSOH TSKgel Super AWM-H (product name, manufactured by Tosoh Corporation)

[0126] Charge carriers: 10 mM LiBr / N-methylpyrrolidone

[0127] Temperature measured: 40℃

[0128] Carrier flow rate: 1.0 ml / min

[0129] Sample concentration: 0.1% by mass

[0130] Detector: RI (Refractive Index) Detector

[0131] (Condition 2)

[0132] Tube String: Use a tube string to connect TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation).

[0133] Support: Tetrahydrofuran

[0134] Temperature measured: 40℃

[0135] Carrier flow rate: 1.0 ml / min

[0136] Sample concentration: 0.1% by mass

[0137] Detector: RI (Refractive Index) Detector

[0138] The pKa of the compound represented by formula (I) is not particularly limited, and an appropriate value can be used, preferably 0.1 to 12. The pKa can be determined by neutralization titration.

[0139] The compound represented by formula (I) may have substituents, and among the substituents that may be present, groups selected from the substituents GZ described below can be cited.

[0140] The compound represented by formula (I) can be synthesized by reference to known synthetic methods, such as the synthetic method described in Patent Document 1, the synthetic method described in the examples described later, etc.

[0141] As specific examples of compounds represented by formula (I), in addition to the compounds synthesized in the examples, the following compounds may also be cited, but the present invention is not limited to these.

[0142] [Chemical Formula 4]

[0143]

[0144] -Substituent GZ-

[0145] The alkyl group (preferably an alkyl group with 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, tert-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl (preferably an alkenyl group with 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl (preferably an alkynyl group with 2 to 20 carbon atoms, such as ethynyl, butyrynyl, phenylethynyl, etc.), cycloalkyl (preferably a cycloalkyl group with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.). When referred to as alkyl in this invention, it generally means... It includes cycloalkyl groups, but is described separately here. Aryl groups (preferably aryl groups with 6 to 26 carbon atoms, such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl groups (preferably aralkyl groups with 7 to 23 carbon atoms, such as benzyl, phenethyl, etc.), and heterocyclic groups (preferably heterocyclic groups with 2 to 20 carbon atoms, more preferably heterocyclic groups having at least one oxygen atom, sulfur atom, and nitrogen atom in a 5 or 6-membered ring). Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups. Examples include tetrahydropyranyl, tetrahydrofuranyl, 2-pyridyl, and 4-pyridyl. The following groups are listed: 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidone, etc.; alkoxy groups (preferably alkoxy groups with 1 to 20 carbon atoms, such as methoxy, ethoxy, isopropoxy, benzyloxy, etc.); aryloxy groups (preferably aryloxy groups with 7 to 26 carbon atoms, such as phenoxy, 1-naphthoxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.); heterocyclic oxy groups (groups with -O- groups bonded to the above heterocyclic groups); alkoxycarbonyl groups (preferably alkoxycarbonyl groups with 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecane, etc.). Oxycarbonyl, etc.), aryloxycarbonyl (preferably aryloxycarbonyl with 6 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthoxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), heterocyclic oxycarbonyl (a group with -O-CO- group bonded to the above heterocyclic group), amino (preferably amino, alkylamino, arylamino containing 0 to 20 carbon atoms, such as amino(-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, aniline, etc.), aminosulfonyl (preferably aminosulfonyl with 0 to 20 carbon atoms, such as N,N-dimethylaminosulfonyl, N-phenylaminosulfonyl, etc.), acyl groups (including alkyl carbonyl, alkenyl carbonyl, alkynyl carbonyl, aryl carbonyl, heterocyclic carbonyl, preferably acyl groups with 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryl, methacryl, crotonyl, benzoyl, naphthoyl, nicotinyl, etc.), acyloxy groups (including alkyl carbonyloxy, alkenyl carbonyloxy, alkynyl carbonyloxy, heterocyclic carbonyloxy, preferably acyloxy groups with 1 to 20 carbon atoms, such as acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyl, etc.), Acryloyloxy, methacryloyloxy, crotonyloxy, nicotinoxy, etc.), aromatic acryloyloxy (preferably aromatic acryloyloxy with 7 to 23 carbon atoms, such as benzoyloxy, naphthyloxy, etc.), carbamoyl (preferably carbamoyl with 1 to 20 carbon atoms, such as N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), amide (preferably amide with 1 to 20 carbon atoms, such as acetamido, benzoylamino, etc.), alkylthio (preferably alkylthio with 1 to 20 carbon atoms, such as methylthio, ethylthio, isopropylthio, benzylthio, etc.) Arylthioyl (preferably arylthioyl with 6 to 26 carbon atoms, such as phenylthioyl, 1-naphthioyl, 3-methylphenylthioyl, 4-methoxyphenylthioyl, etc.), heterocyclic thioyl (a group with -S- group bonded to the above heterocyclic group), alkylsulfonyl (preferably alkylsulfonyl with 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl (preferably arylsulfonyl with 6 to 22 carbon atoms, such as benzenesulfonyl, etc.), alkylsilyl (preferably alkylsilyl with 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, etc.). alkylsilyl, triethylsilyl, etc.), arylsilyl (preferably arylsilyl with 6 to 42 carbon atoms, such as triphenylsilyl), alkoxysilyl (preferably alkoxysilyl with 1 to 20 carbon atoms, such as monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl (preferably aryloxysilyl with 6 to 42 carbon atoms, such as triphenoxysilyl), phosphoryl (preferably phosphoric acid with 0 to 20 carbon atoms, such as -OP(=O)(R, P )2) Phosphonyl group (preferably a phosphonyl group with 0 to 20 carbon atoms, for example, -P(=O)(R P )2) Oxyphosphin group (preferably oxyphosphin group with 0 to 20 carbon atoms, for example, -P(R P 2) Phosphonic acid group (preferably a phosphonic acid group with 0 to 20 carbon atoms, for example, -PO(OR) P 2) Sulfonate (sulfonic acid group), carboxyl group, hydroxyl group, thioalkyl group, cyano group, halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom, etc.).

[0146] RP It is a hydrogen atom or a substituent (preferably a group selected from substituents G and Z).

[0147] Furthermore, each of the groups listed in these substituents GZ can be further replaced by the aforementioned substituents GZ.

[0148] The aforementioned alkyl, alkylene, alkenyl, alkenylene, ynyl and / or ynylene groups can be cyclic or chain-like, and can be straight-chain or branched.

[0149] Methods for the separation and recovery of metal ions

[0150] The metal ion separation and recovery method of the present invention (hereinafter, sometimes referred to as the separation and recovery method of the present invention) is a method of mixing an aqueous phase containing multiple metal ions and an oil phase containing the metal extractant of the present invention. This allows specific metal ions coordinated to the metal extractant of the present invention to move (extract) from the aqueous phase to the oil phase, and to be separated and recovered with high selectivity (preferably high recovery rate). Here, the metal ions extracted into the oil phase can be a portion of the multiple metal ions contained in the aqueous phase, or all types of heterometallic ions contained in the aqueous phase. In the separation and recovery method of the present invention, one type of metal ion, as a valuable metal element, can be extracted into the oil phase with high selectivity (preferably high recovery rate), but one type of heterometallic ion from two or more heterometallic ions, for example, belonging to groups 1 to 14 of the periodic table, can also be extracted into the oil phase with high selectivity (preferably high recovery rate). In particular, the separation and recovery method of the present invention can selectively (preferably with high recovery) extract one of two or more foreign metal ions belonging to Groups 9 to 12 of the periodic table into the oil phase, especially preferably one of cobalt ions and nickel ions, which are foreign metal ions of the same period.

[0151] In the separation and recovery method of the present invention, the metal extractant of the present invention extracts two or more metal ions from a group of multiple metal ions present in the aqueous phase into the oil phase in a wet extraction method. However, it has been found to have the characteristics and functions of being able to extract one metal ion with high selectivity (preferably with high recovery rate), and is suitable for the separation and recovery of two or more metal ions, especially heterogeneous metal ions.

[0152] <Water Phase>

[0153] There are no particular restrictions on the type of water used to form the aqueous phase, but (ultra)pure water, ion-exchanged water, etc., can be used.

[0154] The aqueous phase may contain at least two metal ions belonging to Groups 1 to 14 of the periodic table, preferably at least two metal ions belonging to Groups 3 to 14, and may also contain metal ions belonging to Groups 15 to 17.

[0155] In this invention, it is preferable to include two or more metal ions belonging to Groups 1 to 14, more preferably two or more metal ions belonging to Groups 3 to 14, and even more preferably ions containing at least one transition metal element (a metal element belonging to Groups 3 to 12). In the case of including at least one transition metal element, it is preferable to include two or more metal ions belonging to Groups 4 to 12, more preferably two or more metal ions belonging to Groups 4 to 10, even more preferably two or more metal ions belonging to Groups 8 to 12, particularly preferably two or more metal ions belonging to Groups 9 to 12, and most preferably two or more metal ions belonging to both Groups 9 and 10. There are no particular limitations on the groups of the metal ions, but metal ions belonging to Periods 4 to 6 of the periodic table are preferred, more preferably metal ions belonging to Period 4 or 5. Furthermore, there is no particular limitation on the number of metal ions as long as there are two or more types. For example, it can be set to 2 to 15 types, preferably 2 to 8 types, and more preferably 2 to 5 types.

[0156] There are no particular restrictions on the combination of multiple metal ions. For example, combinations of groups can be included, such as combinations of groups 9 and 10, groups 9 and 12, groups 9 and 11, groups 9, 10 and 12, groups 4 and 9, groups 7, 9 and 10, and groups 7, 8, 9 and 10.

[0157] In this invention, there may be two or more metal ions belonging to each group, but from the viewpoint of exhibiting high selectivity, one type is preferred.

[0158] Specific combinations of metal ions include, for example, combinations containing Co and Ni, combinations containing Co and Zn, combinations containing Co and Cu, combinations containing Rh and Ni, combinations containing Zr and Rh, combinations containing Mn, Co and Ni, combinations containing Mn, Fe, Co and Ni, etc.

[0159] The aqueous phase may contain both metal ions from the same group and metal ions from different groups. The aqueous phase may contain two or more types of metal ions from different groups, preferably two to four, and more preferably two.

[0160] There are no particular restrictions on which group of metallic elements belong, and appropriate atoms can be used. For example, as described below.

[0161] As metallic elements belonging to Group 1, Li, Na, Rb, and Cs are preferred examples.

[0162] As metallic elements belonging to Group 2, Mg, Ca, Sr, and Ba are preferred examples.

[0163] As metallic elements belonging to Group 3, Sc and Y are preferred examples.

[0164] As metallic elements belonging to Group 4, Ti, Zr, and Hf are preferred examples.

[0165] V, Nb, and Ta are preferred examples of metal elements belonging to Group 5.

[0166] As metallic elements belonging to Group 6, Cr, Mo, and W are preferred examples.

[0167] Mn and Tc are preferred examples of metal elements belonging to Group 7.

[0168] As metallic elements belonging to Group 8, Fe, Ru, and Os are preferred examples.

[0169] Co, Rh, and Ir are preferred examples of metal elements belonging to Group 9.

[0170] Ni, Pd, and Pt are preferred examples of metal elements belonging to Group 10.

[0171] As metallic elements belonging to Group 11, Cu, Ag, and Au are preferred examples.

[0172] Zn, Cd, and Hg are preferred examples of metallic elements belonging to Group 12.

[0173] As metallic elements belonging to Group 13, Al, Ga, In, and Tl are preferred examples.

[0174] As metallic elements belonging to Group 14, Ga, Sn, and Pb are preferred examples.

[0175] Sb and Bi are preferred examples of metallic elements belonging to Group 15.

[0176] As a metallic element belonging to Group 16, there are no particular restrictions, but Te is a preferred example.

[0177] As various metal ions, they can be appropriately prepared, for example, using various metal salts (salts of inorganic acids such as nitric acid and sulfuric acid of typical elements, or salts of organic acids such as acetic acid), mixtures of mined metals (ions), recyclables from metal waste, metal recyclables from other wastes (such as those from spent batteries (LiB)), and mixtures thereof. Examples of metal recyclables from spent LiB include those based on known methods such as wet processing and electrolysis.

[0178] The total content of various metal ions in the aqueous phase is not particularly limited and can be set appropriately. For example, it can be set to 1,000 to 1,000,000 ppm by mass, preferably 1,000 to 100,000 ppm by mass, more preferably 1,000 to 80,000 ppm by mass, and even more preferably 2,000 to 60,000 ppm by mass.

[0179] There is no particular limitation on the total content of metal ions belonging to Groups 9 to 12. It can be set appropriately, for example, it can be set to 1,000 to 80,000 ppm by mass, preferably 1,000 to 60,000 ppm by mass, and more preferably 2,000 to 60,000 ppm by mass.

[0180] The total content of metal ions belonging to Groups 3 to 7 and Groups 13 to 16 is not particularly limited and can be set appropriately, but for example, it can be set to 1,000 to 60,000 ppm by mass, preferably 1,000 to 30,000 ppm by mass.

[0181] The content of metal ions belonging to each group is not particularly limited and can be appropriately set. For example, it can be set to 1,000 to 60,000 ppm by mass, preferably 1,000 to 50,000 ppm by mass, and more preferably 2,000 to 30,000 ppm by mass. In addition, when two or more metal ions belonging to each group are contained, the content of metal ions belonging to each group is the total content.

[0182] In this invention, when the aqueous phase contains metal ions from different groups, the content of metal ions belonging to a certain group can be more or less than the content of metal ions belonging to other groups. In the separation and recovery method of this invention, since metal ions can be separated and recovered with high selectivity, it is not necessary to set the content of metal ions belonging to different groups at a specific ratio. For example, the mass ratio of the content of metal ions belonging to another group (e.g., metal ions other than those extracted at maximum extraction rate (including unextracted metal ions)) to the content of metal ions belonging to a specific group (e.g., metal ions extracted at maximum extraction rate) [content of metal ions belonging to a specific group: content of metal ions belonging to another group] can be set to, for example, 100:1 to 10,000, preferably 100:10 to 5,000, more preferably 100:50 to 1,000, and even more preferably 100:70 to 250.

[0183] There are no particular restrictions on the pH of the aqueous phase, and it can be set appropriately. However, if the solubility of metal ions and the formation of complex ions are taken into account, it is preferred to set it to 0.1 to 10, and more preferably to set it to 2.0 to 9.0.

[0184] The pH of the aqueous phase can be adjusted using acids or bases, for example. As an acid, known acids can be used without particular limitation, including inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, as well as organic acids such as formic acid, acetic acid, oxalic acid, organic phosphoric acid, and organic sulfonic acid. As a base, known bases can be used without particular limitation, including inorganic bases and organic bases, with inorganic bases being preferred. Examples of inorganic bases include metal bases such as hydroxides and carbonates of Group 1 or Group 2 metals, and further examples include ammonia and ammonium chloride. Examples of organic bases include organic ammonium salts.

[0185] There are no particular restrictions on the temperature of the aqueous phase; for example, it can be set to 10–60°C.

[0186] The aqueous phase may contain ligands (compounds) that coordinate with metal ions or compounds that generate ligands, as needed.

[0187] The aqueous phase can be prepared by dissolving metal ions in water. There are no particular limitations on the preparation conditions. For example, the preparation temperature can be set between 10 and 60°C.

[0188] In addition to the metal ions mentioned above, the aqueous phase may also contain a masking agent. Known masking agents can be used without particular limitation. Examples include monodentate ligands such as ammonia and chelating agents such as dithizone.

[0189] <Oil phase>

[0190] In the separation and recovery method of the present invention, an oil phase (organic phase) containing one or more metal extractants of the present invention is used for the above-mentioned aqueous phase.

[0191] The metal extractant of the present invention exhibits its solubility in organic solvents and exists in the oil phase to coordinate and bond with metal ions present near the interface between the aqueous and oil phases, thereby demonstrating the function of moving the metal ions into the oil phase. In this invention, solubility relative to organic solvents refers to the property of the metal extractant to dissolve in an organic solvent at a concentration described later.

[0192] There are no particular limitations on the organic solvent used to form the oil phase; any suitable organic solvent can be used. Examples include alcohol solvents, ether solvents, hydrocarbon solvents (aromatic solvents, aliphatic solvents), and halogen solvents. Among these, hydrocarbon solvents are preferred, and various solvents that are fractionation components of petroleum are more preferred. Hydrocarbon solvents such as aromatics, paraffins, cycloalkanes, kerosene, gasoline, naphtha, kerosene, and light oils are even more preferred.

[0193] The content of the metal extractant in the oil phase is appropriately set considering factors such as the content of metal ions and the coordination amount with metal ions. For example, the content in the oil phase can be set to 20 to 10,000 mmol / L (mM), preferably 50 to 1,000 mmol / L, and more preferably 100 to 500 mmol / L.

[0194] There are no particular restrictions on the temperature of the oil phase; for example, it can be set to 10–60°C.

[0195] In addition to the acidic metal extractant of this invention, the oil phase may also contain appropriate components.

[0196] The oil phase can be prepared by dissolving the metal extractant in an organic solvent. There are no particular limitations on the preparation conditions of the oil phase; for example, the preparation temperature can be set to 10–60°C.

[0197] (Contact, Mixing)

[0198] In the separation and recovery method of the present invention, the above-mentioned aqueous phase and oil phase are mixed and allowed to stand.

[0199] There are no particular restrictions on the mixing and settling conditions at this time, and they can be set appropriately. For example, various mixing devices can be used for mixing. Examples of mixing devices include using a magnetic stirrer (stirrer tip), using a mechanical stirrer, and using a mixer. The mixing conditions (stirring speed, stirring time, etc.) are only required to mix the aqueous and oil phases (conditions for coordination bonding between the metal extractant and metal ions), and can be set appropriately according to the combination of metal ions and metal extractant, the mixing temperature, and the mixing device. For example, the stirring speed, such as the rotation speed of a magnetic stirrer, can be set to 80 rpm or more, preferably 100 to 200 rpm. The stirring time is not uniquely determined based on the mixing conditions, but can be set to, for example, 10 minutes to 24 hours. In this invention, since the aqueous and oil phases can be separated at a high phase separation rate, the stirring speed can be set to a high speed, and the stirring time can be set to a long time. There are no particular restrictions on the mixing temperature, and it can be set to, for example, 10 to 60°C.

[0200] The settling conditions are not particularly limited as long as the aqueous and oil phases separate into two layers, and can be appropriately set. In wet extraction, the settling time is typically set to 10 minutes to 24 hours after mixing stops. However, in this invention, the aqueous and oil phases can be separated at a high rate, thus allowing the settling time to be set shorter than usual to improve the productivity of the wet extraction method. For example, the settling time can be set to less than 5 minutes after mixing stops, preferably less than 4 minutes. The settling temperature is not particularly limited, and can be set to, for example, 10 to 60°C.

[0201] In the mixing of the aqueous and oil phases, the mixing ratio of the aqueous and oil phases is appropriately set according to the content (concentration) of metal ions and the content (concentration) of the metal extractant, and is not uniquely determined. For example, when mixing aqueous and oil phases that meet the above-mentioned concentrations, the ratio of the oil phase to 100 mL of the aqueous phase can be set to 50 to 2,000 mL, preferably 80 to 1,000 mL, and more preferably 80 to 200 mL. On the other hand, if the metal ions present in the aqueous phase are of interest, the oil phase is preferably mixed at a ratio of 0.5 to 20 moles of the metal extractant relative to the total content (moles) of the metal ions, more preferably at a ratio of 0.5 to 10 moles of the metal extractant. Furthermore, the content of the metal extractant relative to the total content of metal ions that the metal extractant can coordinate with (also called the mixing amount; the ratio of the number of moles of the metal extractant to the total number of moles of the metal ions: molar ratio) can be set, for example, to 0.5 to 10.0 equivalents, preferably 0.5 to 6.0 equivalents. Here, the metal ions that can be coordinated by the metal extractant refer to the metal ions that are coordinated by the metal extractant and extracted into the oil phase.

[0202] In the mixing of the aqueous and oil phases, the pH of the mixed system can also be adjusted. Here, the pH set for the specific metal ion being extracted is not unique, but rather appropriately determined considering factors such as the pKa of the metal extractant, the complexation constant between the metal extractant and the metal ion, and the coordination number of the metal ion. The pH of the mixed system is preferably set to 0.01–14, for example, more preferably 0.1–10. From the viewpoint of selectivity and phase separation rate, and further from the viewpoint of recovery rate, it is even more preferably set to 0.5–7.0, particularly preferably 1.0–6.5, and most preferably 2.5–6.5. In the case of separating and recovering metal ions belonging to Group 9 and Group 10, the pH of the aqueous phase is most preferably set to 3.0–6.5 within the above range.

[0203] pH can be prepared using the aforementioned acids or bases or their aqueous solutions, but the use of ammonia or ammonium salts is one of the preferred methods.

[0204] When adjusting the pH of the mixing system during the mixing of aqueous and oil phases, the mixing of the aqueous and oil phases and the subsequent settling are carried out after pH adjustment.

[0205] The two-phase separated fluid (solvent extraction phase, solvent extraction system) obtained by mixing the aqueous and oil phases and allowing them to stand exists in a layered phase separation state with the aqueous and oil phases in contact. Moreover, the metal ions coordinated and bonded by the metal extractant among the aforementioned metal ions exist (move) in the oil phase.

[0206] Ideally, the number of metal ions extracted into the oil phase is one, but sometimes it is two or more. In such cases, for example, it can be set to 2 to 10, preferably 2 to 6, and more preferably 2 or 3. There is no particular limitation on the number of metal ions extracted into the oil phase from a variety of metal ions. For example, it is preferable that they are the same as the two or more heterometallic ions (combinations) contained in the aqueous phase as described above.

[0207] The simple method of mixing the aqueous phase and oil phase and allowing them to stand in the separation and recovery method of the present invention enables the separation, recovery and extraction of specific metal ions from a variety of metal ions with high selectivity (preferably with high recovery rate), especially the extraction of ions of two or more metal elements and the separation and recovery of one of the metal ions with high selectivity (preferably with high recovery rate).

[0208] The specific metal ion that can be selectively separated and recovered (preferably with high recovery) is not uniquely determined based on the metal ion's group or period, its content, or the type of metal extractant. For example, when extracting both Group 9 and Group 10 metal ions into the oil phase, Group 9 metal ions can be selectively separated and recovered (preferably with high recovery). In particular, when extracting Co ions as Group 9 and Ni ions as Group 10, Co ions can be selectively separated and recovered (preferably with high recovery). Furthermore, when extracting both Group 9 and Group 11 metal ions into the oil phase, Group 11 metal ions can be selectively separated and recovered (preferably with high recovery). Furthermore, when metal ions belonging to Group 9, Group 10, and Group 12 are extracted into the oil phase, metal ions belonging to Group 10 are usually not extracted, and metal ions belonging to Group 12 can be separated and recovered with high selectivity (preferably with high recovery).

[0209] As described above, the separation and recovery method of the present invention can selectively (preferably with high recovery) extract one or more metal ions from a variety of metal ions present in the aqueous phase into the oil phase and recover them. In particular, the separation and recovery method of the present invention can extract two or more metal ions while simultaneously recovering one of them with high selectivity (preferably with high recovery). Therefore, by further providing the aqueous phase containing two or more metal ions, which has been back-extracted from the oil phase, to the separation and recovery method of the present invention, the selectivity of the single metal ion can be further improved without significantly impairing the recovery rate. As a result, high-purity metal ions can be recovered with a preferably high recovery rate.

[0210] This separation and recovery method of the present invention can also be called an extraction method for two or more metal ions.

[0211] In the separation and recovery method of the present invention, the metal extractant can independently coordinate with a metal ion to extract the metal ion into the oil phase. Therefore, the aqueous phase and the oil phase may not contain compounds that coordinate with the metal ion or compounds that generate ligands, or other compounds that synergistically act with the metal extractant of the present invention to extract the metal ion, such as known metal extractants. In the separation and recovery method of the present invention, an aqueous phase containing a specific metal ion as an essential component and an oil phase containing the metal extractant of the present invention as an essential component are typically used.

[0212] The separation and recovery method of the present invention can include steps other than the step of mixing the aqueous and oil phases and allowing them to stand. Examples include steps such as pre-mixing the aqueous and oil phases before adjusting the pH, back-extracting (separating) metal ions from the oil phase obtained in the step of mixing the aqueous and oil phases and allowing them to stand (a step of back-extracting metal ions from the oil phase and recovering the metal extractant), recovering the back-extracted metal ions as a compound (salt), purifying the back-extracted metal ions or their compounds, purifying the recovered metal extractant, and pre-removing ions belonging to Group 1 or Group 2 of the periodic table. As a method for back-extracting (separating) metal ions from the oil phase, known methods can be used without particular limitation; for example, the liquid phase can be acidic, for example, at pH 2 to 4, by using inorganic acids such as sulfuric acid, hydrochloric acid, or nitric acid. As a method for recovering the back-extracted metal ions as a compound, known methods can be used without particular limitation.

[0213] Furthermore, the separation and recovery method of the present invention can be carried out through intermittent processing or through continuous processing.

[0214] There are no particular limitations on the apparatus used to implement the separation and recovery method of the present invention, and known equipment can be used. For example, a separating funnel or a mixing settling device can be used. Furthermore, contact and mixing devices that utilize a liquid delivery device, such as a flow synthesis device or an emulsion flow device, can also be used. The contact, mixing, and settling conditions in continuous processing can be applied according to the above-mentioned conditions. In addition, the amount of flowing aqueous phase used can be set to be greater than the mixing ratio of the aqueous layer and the oil phase described above.

[0215] Example

[0216] The present invention will now be described in further detail with reference to embodiments, but the explanation of the present invention is not limited thereto.

[0217] In the following examples, the terms "parts" and "%" of composition are based on mass unless otherwise stated. In this invention, "room temperature" means 25°C.

[0218] [Synthesis and preparation of compounds]

[0219] The compounds shown below were synthesized or prepared.

[0220] In addition, the PC-88A ((2-ethylhexyl)phosphonic acid mono-2-ethylhexyl) shown below uses a commercially available product (manufactured by Tokyo Chemical Industry Co., Ltd.), and the VA-10 shown below uses a commercially available product (Versatic acid 10, manufactured by HEXION Corporation).

[0221] [Chemical Formula 5]

[0222]

[0223] <Synthesis of Compound E-1>

[0224] Compound E-1 was synthesized as follows.

[0225] Specifically, 89 g of diethyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) and 450 g of tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added to a 1 L three-necked flask and stirred thoroughly. While the flask was chilled, 23.2 g of sodium hydride (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added, and the mixture was stirred for 20 minutes under chilled conditions. Then, the reaction mixture was heated and stirred under reflux for 30 minutes. Next, while the flask was chilled, 70.0 g of 1-bromo-2-ethylhexane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to the obtained reaction mixture over 20 minutes, and the mixture was stirred at an internal temperature of 45°C for 24 hours. After adding 300 g of water to the thus obtained reaction mixture, the mixture was extracted with toluene, and the solvent was distilled under reduced pressure to obtain 107 g of a yellow liquid.

[0226] Next, the obtained yellow liquid and 400 g of dichloromethane (manufactured by FUJIFILM WakoPure Chemical Corporation) were added to a 1 L three-necked flask and stirred thoroughly. 113 g of trimethylbromosilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was further added to the flask, and the mixture was stirred at room temperature for 4 hours. After distilling the solvent from the obtained reaction solution under reduced pressure, 530 g of methanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added, and the mixture was stirred at an internal temperature of 40 °C for 3 hours. 200 mL of a 4 mol / L sodium hydroxide aqueous solution was added to the thus obtained reaction solution, and the aqueous layer was washed twice with toluene. 65 mL of concentrated hydrochloric acid was added to the obtained aqueous solution, and after extraction with toluene, the solvent was distilled under reduced pressure to obtain 43.6 g of compound A (62% yield, 2 steps).

[0227] Add 20.0 g of compound A and FINEOXOCOL 1600K (branched C) to a 500 mL three-necked flask. 16 H 3325.0 g of OH (manufactured by Nissan Chemical Corporation) and 120 g of tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation) were stirred and heated to reflux. After 3 hours, a solution of 23.4 g of dicyclohexylcarbodiimide (manufactured by FUJIFILM Wako Pure Chemical Corporation) dissolved in 120 g of tetrahydrofuran was added dropwise, and the mixture was stirred for 4 hours. The resulting reaction solution was brought to room temperature, and the solvent was distilled off under reduced pressure from the filtrate obtained after filtering to remove the white solid. The crude product was dissolved in toluene, washed with water, and the solvent was distilled off under reduced pressure to obtain 32.0 g (74% yield) of compound E-1 as a pale yellow liquid.

[0228] The following describes the identification of compound E-1, which was synthesized in this manner.

[0229] That is, compound E-1 is dissolved in deuterated chloroform and the concentration is determined. 1 H-NMR (device: BLUKER400), the obtained graphs are shown in... Figure 1 .

[0230] δ (ppm): 9.65 (1H, br s), 3.89 (2H, t, J = 5.6Hz), 1.80-1.21 (36H, m), 0.91-0.86-(12H, m)

[0231] Furthermore, the m / z 419 obtained by HPLC-MS is similar to [M+H] + Consistent (E-1 precise molecular weight 418).

[0232] Based on the above, the obtained compound was identified as having the structure shown in E-1 above.

[0233] <Synthesis of compounds E-2 to E-6 and E-9>

[0234] In the synthesis of compound E-1, 1-bromo-2-ethylhexane or FINEOXOCOLl 1600K was replaced with R as shown in Table 1 below, which has the same chemical formula as above. 1 and R 2 The corresponding group halides or alcohols, except that compounds E-2 to E-6 and E-9 were synthesized in the same manner as compound E-1.

[0235] <Synthesis of Compound E-7>

[0236] Add FINEOXOCOL 1600K (branched C) to a 500mL three-necked flask. 16H 33 30.0 g of triphenylphosphine (manufactured by Nissan Chemical Corporation), 49.2 g of carbon tetrabromide (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 160 g of dichloromethane (manufactured by FUJIFILM Wako Pure Chemical Corporation) were mixed and stirred while being cooled in an ice bath. After 10 minutes, a solution consisting of 48.7 g of triphenylphosphine (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 130 g of dichloromethane was added dropwise to the obtained reaction solution. The reaction solution was then heated to room temperature and stirred for 2 hours. A 4M sodium hydroxide solution was added to the solution, and after extraction with dichloromethane, the solvent was distilled under reduced pressure to obtain a pale yellow liquid product (branched C). 16 H 33 Br)(yield of 90%).

[0237] 1.9 g of magnesium (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 100 g of diethyl ether were added to a 300 mL three-necked flask and stirred at room temperature. 22.0 g of the product was then added dropwise, generating Grignard reagent. Next, while maintaining the reaction solution temperature below 15 °C, 5.0 g of dibutyl phosphite was added, and the reaction solution was heated and stirred under reflux for 5 hours. While cooling the obtained reaction solution in an ice bath, 10% sulfuric acid was added dropwise, the organic layer was washed with a 15% sodium carbonate aqueous solution, and the solvent was distilled under reduced pressure. The crude product was purified by column chromatography, yielding a colorless, transparent liquid containing branched C16 chains with two hydroxyl groups each substituted for one of the two hydroxyl groups. 16 H 33 Phosphorous acid of the base (yield 84%).

[0238] 78 g of hydrogen peroxide solution (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 10.0 g of the aforementioned phosphorous acid were added to a 200 mL three-necked flask, and the mixture was stirred at room temperature. The reaction mixture was then heated to 65 °C and stirred for 24 hours. After adding 100 g of saturated sodium thiosulfate aqueous solution, the mixture was extracted with toluene, and the solvent was distilled under reduced pressure to obtain compound E-7 in a colorless, transparent liquid state (yield 96%).

[0239] <Synthesis of Compound E-8>

[0240] Add 17.4 g of vinyl diphosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and FINEOXOCOL 180 (branched C) to a 1 L three-necked flask. 18 H 37 49.5g of OH (manufactured by Nissan Chemical Corporation) and 200g of tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation) were stirred and dissolved under reflux.

[0241] In addition, 41.6 g of N,N'-dicyclohexylcarbodiimide (DCC, manufactured by FUJIFILM WakoPure Chemical Corporation) and 180 g of tetrahydrofuran were added to a 500 mL graduated cylinder and mixed to prepare a DCC solution.

[0242] The DCC solution was added dropwise to the three-necked flask over 3 hours, and the mixture was stirred for an additional 5 hours after the addition was completed. The resulting solution was allowed to cool naturally at room temperature, filtered to remove the precipitated white crystals, and washed with toluene. The solvent was then distilled from the filtrate under reduced pressure to obtain a colorless, transparent liquid, compound E-8 (98% yield).

[0243] <Synthesis of Compound T-1>

[0244] Compound T-1 was synthesized with reference to Example 1 of Patent Document 1.

[0245] <Synthesis of Compound T-2>

[0246] In the synthesis of compound E-1, FINEOXOCOL 1600K was replaced with isodecanol. Otherwise, compound T-2 was synthesized in the same manner as compound E-1. Compound T-2 was identified in the same way as compound E-1.

[0247] The compounds synthesized in the above manner were identified in the same way as compound E-1.

[0248] Regarding the synthesized or prepared compound, its molecular weight and its relationship with R... 1 and R 2 The molecular weights and carbon number of the corresponding substituents are shown in Table 1. Additionally, in Table 1, for the "P" atom in the basic structure of the chemical formula, the substituent on the left is designated as R. 1 Set the substituent on the right side to R. 2 .

[0249] [Table 1]

[0250]

[0251] [Preparation of aqueous solutions containing metal ions]

[0252] 81.1 g of cobalt(II) sulfate heptahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 81.3 g of nickel(II) sulfate heptahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added to a 1 L volumetric flask, dissolved in ultrapure water, and stirred at 40 °C to prepare an aqueous solution (W1) containing metal ions.

[0253] Furthermore, based on the combinations of metal ions shown in the "Metal ion concentration (ppm) in the aqueous phase before extraction" column of Table 2-1, each sulfate was dissolved in ultrapure water to prepare aqueous solutions (W2) to (W4) containing metal ions.

[0254] The following shows the pH results of the prepared aqueous solutions (W1) to (W4) containing metal ions, measured using a pH meter (SK-620pHII, manufactured by SATOTECH).

[0255] Aqueous solution containing metal ions (W1): 6.6

[0256] Aqueous solution containing metal ions (W2): 6.2

[0257] Aqueous solution containing metal ions (W3): 6.5

[0258] Aqueous solution containing metal ions (W4): 7.0

[0259] <Preparation of Metal Extractant Solution (Oil Phase)>

[0260] Each synthesized or prepared compound was added to a 100 mL volumetric flask and brought to a final volume using kerosene (manufactured by FUJIFILM Wako PureChemical Corporation) at room temperature, thereby preparing metal extractant solutions (Y1) to (Y9) and (Yc1) to (Yc4) (concentration 450 mM) containing each compound as a metal extractant.

[0261] [Example 1]

[0262] In a 30 mL vial, 10 mL of the prepared aqueous solution (W1) containing metal ions was added to 10 mL of the extractant solution (Y1), and stirred at 25°C (150 rpm) for 30 minutes (premixing) using a stirrer tip (6 mm in diameter, 20 mm in length). At this point, the mixed amount (in equivalents) of compound E-1 relative to the total content of the coordinateable metal ions (with the same meaning as the extracted metal ions, Co and Ni in Example 1) was 0.78. Then, 10 M sodium hydroxide aqueous solution or 10 M hydrochloric acid was added to adjust the pH of the mixture to the value shown in the "pH at Mixing" column of Table 2-2, and the mixture was further stirred at 25°C for 30 minutes (150 rpm), followed by standing at the same temperature for 1 hour. After confirming separation into an organic phase (oil phase) and an aqueous phase, the aqueous phase was separated and collected, thus achieving the separation and recovery of metal ions.

[0263] In addition, the pH of the mixture was measured using a pH meter (SK-620pHII, manufactured by SATOTECH).

[0264] The metal ions extracted in Example 1 are shown in the "Type" column of the "Extracted Metal Ions" column in Table 2-2, and the metal ions extracted at the maximum extraction amount are shown in the "Maximum Extracted Ions" column of the same column in Table 2-2.

[0265] <Examples 2-12 and Comparative Examples 1-4>

[0266] In Example 1, the aqueous solution containing metal ions and the extractant solution were changed to the combinations shown in the "Aqueous Phase" column of Table 2-1 and the "Oil Phase" column of Table 2-2 (hereinafter, Table 2-1 and Table 2-2 are collectively referred to as Table 2). The pH of the aqueous and oil phases was set to the value shown in the "pH at Mixing" column of Table 2-2. The mixture was then allowed to stand. Otherwise, the separation and recovery of metal ions in Examples 2-12 and Comparative Examples 1-4 were performed in the same manner as in Example 1. In each example, the extracted metal ions are shown in the "Type" column of the "Extracted Metal Ions" column of Table 2-2, and the metal ions extracted at the maximum extraction rate are shown in the "Maximum Extracted Ions" column of the same column in Table 2-2.

[0267] For each aqueous phase used in the examples and comparative examples, and for each aqueous phase after extraction, the content of dissolved metal ions was quantified using an inductively coupled plasma optical emission spectrometry (ICP-OES) apparatus (Optima 7300D (trade name), manufactured by PerkinElmer Co., Ltd.). The measured values ​​of dissolved metal ion content in each aqueous phase used in the examples and comparative examples are shown in the "Metal ion concentration in the aqueous phase before extraction (ppm)" column of Table 2-1, and the measured values ​​of dissolved metal ion content in each aqueous phase after mixing in the examples and comparative examples are shown in the "Metal ion concentration in the aqueous phase after extraction (ppm)" column of Table 2-1. Note that the comma in the metal ion concentration table indicates a decimal point, not a digit separator.

[0268] <Evaluation 1: Evaluation of Selectivity (Separation Ability)>

[0269] In each embodiment and comparative example, the extraction amount (differential, unit: ppm) of each metal ion was calculated based on the metal ion concentration in the aqueous phase before extraction and the metal ion concentration in the aqueous phase after extraction. The selection ratio was calculated by dividing the extraction amount (ppm) of the metal ion with the highest extraction amount by the total extraction amount (ppm) of the other metal ions. The results are shown in the "Selection Ratio" column of Table 2-2.

[0270] In this experiment, the higher the selectivity ratio, the better the selectivity (separation ability) of a specific metal ion; a ratio of 3.0 or higher is considered acceptable.

[0271] <Evaluation 2: Phase Separation Velocity>

[0272] In each embodiment and comparative example, after stirring at 25°C for 30 minutes and then standing at the same temperature, the time elapsed until the two phases separated was measured, and the phase separation rate of the aqueous phase and the oil phase was evaluated.

[0273] In this experiment, the shorter the time, the higher the phase separation rate, and the evaluation standard "D" and above is the qualified level.

[0274] -Evaluation Criteria-

[0275] A: Less than 2 minutes

[0276] B: More than 2 minutes but less than 3 minutes

[0277] C: More than 3 minutes but less than 4 minutes

[0278] D: More than 4 minutes but less than 5 minutes

[0279] E: More than 5 minutes but less than 10 minutes

[0280] F: 10 minutes or more

[0281] [Table 2-1]

[0282]

[0283] [Table 2-2]

[0284]

[0285] The following information can be gleaned from the results shown in Table 2.

[0286] In the separation and recovery of metal ions based on wet extraction, Comparative Examples 1 to 4, which used conventional metal extractants PC-88A, VA-10, T-1, and T-2, only extracted two metal ions present in the aqueous solution (W1) containing metal ions into the oil phase. Furthermore, not only Co but also Ni were extracted in large quantities, resulting in a low selectivity for Co ions with the maximum extraction yield. Moreover, in Comparative Examples 1 to 4, the time required for separation into two phases was long (low phase separation rate), leading to poor productivity of the wet extraction method.

[0287] In contrast, Examples 1-12, which used compounds E-1 to E-9 of the present invention as metal extractants, extracted two metal ions present in the aqueous solution containing metal ions into the oil phase. However, the metal ions with the highest extraction yield (Examples 1-5, 8, and 10-12: Co ions, Example 6: Zn ions, Example 7: Cu ions, Example 9: Rh ions) could extract almost all of the metal ions other than those with the highest extraction yield from the aqueous phase to the oil phase with a high selectivity (high recovery rate). Moreover, in Examples 1-12, the time until separation into two phases was short (high phase separation rate), which improved the productivity of the wet extraction method.

[0288] In addition, the concentration of metal ions in the water layer was reduced to 1 / 5. Otherwise, the experiment was conducted in the same manner as in Examples 1-12 and Comparative Examples 1-4, and the same results were obtained.

[0289] Thus, it is known that if the compound of the present invention is used as a metal extractant in a wet extraction method, it is possible to rapidly separate the aqueous phase from the oil phase while simultaneously separating and recovering metal ions present in the aqueous phase with high selectivity and high recovery rate. Furthermore, it is known that among two or more metal ions belonging to different groups with similar physical and chemical behaviors, it is possible to rapidly separate the aqueous phase from the oil phase while simultaneously separating and recovering a specific metal ion with high selectivity and high recovery rate, particularly capable of separating and recovering one metal ion belonging to Group 9 and Group 10 that can be recovered from waste LiB.

[0290] Based on the above results, it can be seen that by back-extracting the oil phase obtained in the above embodiments under normal methods and conditions, metal ions extracted into the oil phase with high selectivity and high recovery rate can be separated and recovered simply and with high productivity without compromising high selectivity.

[0291] In techniques for recovering a specific metal ion from an aqueous phase containing multiple metal ions, it is often difficult to recover the specific metal ion with high selectivity and recovery rate. Maintaining high selectivity often results in a decrease in recovery rate, thus requiring multiple separation and recovery operations to achieve the desired recovery rate. In contrast, this invention can extract almost the entire amount of one of two different metal ions from the aqueous phase to the oil phase using a simple and highly productive method. Therefore, considering the fact that this invention recovers one metal ion from the obtained oil phase with high recovery rate and further improved selectivity through a reverse extraction process or similar steps, while simultaneously achieving high productivity with few and simple steps, the technical significance of this invention is also significant.

[0292] The invention and its methods have been described together, but unless specifically stated otherwise, it is not intended to limit the invention to any of the details described, and it is to be interpreted broadly without departing from the spirit of the invention as shown in the appended claims.

[0293] This application claims priority based on Japanese Patent Application 2023-050476, filed on March 27, 2023, the contents of which are incorporated herein by reference and are part of the description herein.

Claims

1. A metal extractant for extracting metal ions present in an aqueous phase into an oil phase, and represented by the following formula (I), [Chemical Formula 1] In equation (I), R 1 and R 2 These represent substituents with a molecular weight of 100 or more, wherein at least one of the substituents has a molecular weight of 160 or more. Y P Represents oxygen or sulfur atoms. Z represents hydroxyl, thioalkyl, or hydroxyaryl. L represents a single bond; however, when n is 2 or more, L sandwiched between two adjacent P bonds represents a single bond or a linker. n is an integer from 1 to 6.

2. The metal extractant according to claim 1, wherein, The R 1 and R 2 At least one of them is a substituent containing any one of nitrogen, oxygen and sulfur atoms.

3. The metal extractant according to claim 1, wherein, The value of n is 1.

4. The metal extractant according to claim 1, wherein, The R 1 and R 2 At least one of them is a substituent with a branched structure.

5. The metal extractant according to claim 1, wherein, The R 1 and R 2 At least one of them is a substituent containing a hydrocarbon group having 3 or more branched carbon atoms or a substituent containing a hydrocarbon group having 9 or more carbon atoms.

6. The metal extractant according to claim 1, wherein, The R 1 and R 2 At least one of them is a substituent containing a hydrocarbon group having one or more branched carbon atoms and having a carbon number of nine or more.

7. The metal extractant according to claim 1, wherein, The R 1 and R 2 At least one of them is a substituent containing a ring structure.

8. The metal extractant according to claim 1, wherein, The metal ions are ions of metal elements belonging to groups 1 to 14 of the periodic table.

9. The metal extractant according to claim 1, used for extracting and separating two or more metal ions belonging to different groups in the periodic table from the metal ions.

10. The metal extractant according to claim 6, used for extracting and separating two or more metal ions belonging to different groups in the periodic table from the metal ions.

11. A method for separating and recovering metal ions, comprising mixing an aqueous phase containing multiple metal ions and an oil phase containing a metal extractant as described in any one of claims 1 to 10.

12. A compound represented by the following formula (I), [Chemical Formula 2] In equation (I), R 1 and R 2 These represent substituents with a molecular weight of 100 or more, wherein at least one of the substituents has a molecular weight of 160 or more, R 1 and R 2 At least one of them represents a substituent with a branched structure. Y P Represents oxygen or sulfur atoms. Z represents hydroxyl, thioalkyl, or hydroxyaryl. L represents a single bond; however, when n is 2 or more, L sandwiched between two adjacent P bonds represents a single bond or a linker. n is an integer from 1 to 6.

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