Noble metal adsorption material

Abstract

To provide new technical means having excellent noble metal adsorption to various noble metals.SOLUTION: There is provided a noble metal adsorption material in which a silica carrier is modified with at least an amino group-containing group represented by formula (I) (wherein R1 is a divalent C1 to 20 carbohydrate moiety which may be substituted with one or more substituents, Z1 is a bond or NR2, R2 is a hydrogen or a C1 to 20 hydrocarbon group which may be substituted with one or more substituents, R3 is a divalent C1 to 20 carbohydrate moiety which may be substituted with one or more substituents, and R4 is a hydrogen or a C1 to 20 hydrocarbon group which may be substituted with one or more substituents).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to precious metal adsorbent materials. [Background technology]

[0002] Precious metals (e.g., platinum group metals) are used in a wide variety of applications, for example as raw materials for homogeneous and heterogeneous catalysts. However, it is known that these precious metals (or precious metal elements) can be undesirable if they are mixed into final products (e.g., medicines, foods, etc.), and are generally expensive. Furthermore, from the perspective of the SDGs, it can be said that the reuse of precious metals is required. Therefore, various technologies for recovering precious metals are being investigated.

[0003] For example, Patent Document 1 discloses that when an aqueous solution of a precious metal such as sodium tetrachloropalladate, tetrachloroplatinum, or tetrachloroauric acid is brought into contact with an amide compound having a specific structure, the amide compound acts as an extractant for the precious metal.

[0004] Patent Document 2 discloses that a platinum separating agent prepared by modifying silica gel with 3-aminopropyltrimethoxysilane and then treating it with 3,5-bis(trifluoromethyl)phenylboronic acid and ethylthioacetic acid separated precious metals from a hydrochloric acid solution containing platinum and palladium ions.

[0005] Furthermore, Patent Document 3 discloses a palladium adsorbent in which a porous hollow fiber membrane made of silica alumina is modified with 3-aminopropyltriethoxysilane. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-31719 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-133227 [Patent Document 3] International Publication No. 2017 / 204154 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have found through their investigations that the precious metal separation materials disclosed in Patent Documents 1 to 3 have large differences in adsorption rates depending on the pH of the solution, the compounds coexisting in the solution, the form of the precious metal in the solution (for example, the structure of the complex when a platinum group element forms a complex), etc., and that adsorption can be extremely difficult depending on the type of precious metal complex. Therefore, with conventional precious metal adsorption materials, it was necessary to use them appropriately depending on the form of the precious metal to be adsorbed, or in some cases adsorption was extremely difficult in the first place.

[0008] Therefore, one object of the present disclosure is to provide a new technical means having excellent noble metal adsorption for a wide range of noble metals. [Means for solving the problem]

[0009] The present inventors have found that a noble metal adsorption material in which specific amino group-containing groups are grafted onto a silica support can exhibit excellent noble metal adsorption properties. The present disclosure is based on this finding.

[0010] According to one embodiment of the present disclosure, the silica support comprises an amino group-containing group represented by formula (I): [ka] (In the formula, R1 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, Z1 is a bond or NR2; R2 is hydrogen or C optionally substituted with one or more substituents. 1~20 is a hydrocarbon group, R3 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, R4 is a C group optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) A precious metal adsorbent material is provided, which is at least modified with [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a precious metal adsorption material that can have excellent precious metal adsorption for a wide range of precious metals. DETAILED DESCRIPTION OF THE INVENTION

[0012] According to one embodiment of the present disclosure, the silica support comprises an amino group-containing group represented by formula (I): [ka] (In the formula, R1 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, Z1 is a bond or NR2; R2 is hydrogen or C optionally substituted with one or more substituents. 1~20 is a hydrocarbon group, R3 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, R4 is hydrogen or C optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) The precious metal-adsorbing material of the present disclosure is described in detail below.

[0013] [Silica support] The "silica carrier" of the present disclosure is not particularly limited as long as it is one to which the amino group-containing group represented by formula (I) can be grafted.

[0014] The silica support may be, for example, particulate, gel-like, or colloidal, but is preferably particulate from the viewpoint of ease of filtration of the noble metal adsorption material in the reaction system.

[0015] The shape of the silica carrier may be, for example, a molded geometric shape such as a sphere, a columnar shape, or a cylindrical shape, or the space may be partitioned by a wall of any shape. The silica carrier is preferably spherical from the viewpoint of more efficiently adsorbing the precious metal element and / or from the viewpoint of being less likely to cause clogging when filtering out the precious metal-adsorbing material.

[0016] The size of the silica carrier is not particularly limited as long as the objectives of the present disclosure can be achieved. When the geometric surface area per unit volume or per weight in bulk of the silica carrier is increased, more amino group-containing groups represented by formula (I) can be grafted. On the other hand, if the surface area of ​​the silica carrier is too large, efficient filtration may be hindered. From this perspective, the silica carrier may have, for example, a volume-based cumulative 10% particle diameter (D10 diameter) of about 10 to about 300 μm, preferably about 20 to about 200 μm, more preferably about 30 to about 100 μm, and even more preferably about 40 to about 80 μm. The D10 diameter in the present disclosure is a value measured using a laser diffraction particle size analyzer.

[0017] The specific surface area of ​​the silica carrier is not particularly limited as long as the object of the present disclosure can be achieved. A silica carrier with a large specific surface area is advantageous in that the area per carrier weight that can be modified with the amino group-containing group represented by formula (I) is large, and therefore the noble metal can be adsorbed more efficiently. Furthermore, from the viewpoint of the stability of the silica carrier as a carrier and the density of the amino group-containing group represented by formula (I) that is modified on the carrier surface, it is advantageous that the specific surface area value is not too large. From this viewpoint, the specific surface area of ​​the silica carrier is, for example, about 200 to about 2000 m 2 / g, preferably about 300 to about 1500m 2 / g, more preferably about 500 to about 1000 m2 / g, more preferably about 600 to about 900m 2 / g. The specific surface area of ​​the silica carrier in the present disclosure is a value measured by a nitrogen gas adsorption method.

[0018] The pore volume of the silica carrier is not particularly limited as long as the object of the present disclosure can be achieved. The pore volume of the silica carrier may be, for example, about 0.3 to about 5 mL / g, preferably about 0.8 to about 3 mL / g, and more preferably about 1 to about 2 mL / g. The pore volume of the silica carrier in the present disclosure is a value measured by nitrogen gas adsorption method.

[0019] The average pore diameter of the silica carrier is not particularly limited as long as the object of the present disclosure can be achieved. The average pore diameter of the silica carrier may be, for example, about 1 to about 40 nm, preferably about 2 to about 20 nm, and more preferably about 3 to about 10 nm. The average pore diameter of the silica carrier in the present disclosure is a value measured by nitrogen gas adsorption method.

[0020] The water content of the silica carrier is not particularly limited as long as the objectives of the present disclosure can be achieved. The water content of the silica carrier can be appropriately adjusted using conventional methods such as drying or immersion in water. The water content of the silica carrier may be, for example, about 0.03 to about 3 wt%, preferably about 0.1 to about 1 wt%, and more preferably about 0.2 to about 0.5 wt%. If the water content of the silica carrier exceeds 3 wt%, the surface of the silica carrier may be covered with water molecules, which may prevent efficient grafting of the amino group-containing group represented by formula (I) and / or may cause aggregation of the silica carrier, resulting in uneven grafting of the amino group-containing group represented by formula (I). Note that the water content of the silica carrier in the present disclosure is determined by the mass difference between the silica carrier after drying at 110°C for 16 hours and the silica carrier before the treatment.

[0021] [Amino group-containing group represented by formula (I)] According to one embodiment of the present disclosure, the precious metal-adsorbing material of the present disclosure comprises an amino group-containing group represented by formula (I): [ka] (In the formula, R1 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, Z1 is a bond or NR2; R2 is hydrogen or C optionally substituted with one or more substituents. 1~20 is a hydrocarbon group, R3 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, R4 is hydrogen or C optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) It is said to be at least modified by

[0022] In this disclosure, 1~20 "Hydrocarbon group" means a group containing hydrogen atoms and 1 to 20 carbon atoms. 1~20 The hydrocarbon group may be linear, branched, or cyclic, and may be saturated or unsaturated. 1~20 The hydrocarbon group may contain one or more ring structures. 1~20 The hydrocarbon group is not particularly limited, but examples thereof include C 1~20 Aliphatic hydrocarbon group, C 5~20 Examples include aromatic hydrocarbon groups. 1~20 The hydrocarbon group may have one or more nitrogen atoms, oxygen atoms, sulfur atoms, etc. at its terminals or in the molecular chain.

[0023] In this disclosure, 1~20 The "aliphatic hydrocarbon group" may be linear, branched, or cyclic, may be saturated or unsaturated, and may contain one or more ring structures. 1~20 The aliphatic hydrocarbon group is not particularly limited, but may be any of C 1~20 Alkyl, C 2~20 Alkenyl, C 2~20 Alkynyl, C 3~20Cycloalkyl, C 3~20 Examples thereof include cycloalkenyl.

[0024] In this disclosure, 5~20 The "aromatic hydrocarbon group" may be either a monocyclic or polycyclic (e.g., bicyclic or tricyclic) group, or may be an aromatic heterocyclic group (also referred to as "heteroaryl" in the present disclosure). The "aromatic hydrocarbon group" is not particularly limited, but examples thereof include C 6~20 Aryl (e.g., phenyl, naphthyl), C 5~20 Examples include heteroaryl (for example, furyl, thienyl, pyridyl, indolyl, quinolyl, isoquinolyl, imidazolyl) and the like.

[0025] In this disclosure, 1~20 "Alkyl" means a saturated straight or branched chain hydrocarbon group containing one or more carbon atoms (including, but not limited to, for example, methyl, ethyl, propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, etc.).

[0026] In this disclosure, 3~20 "Cycloalkyl" means a saturated monocyclic or bicyclic hydrocarbon group containing three or more carbon atoms (including, but not limited to, for example, cyclopropyl, cyclobutyl, cyclohexyl, etc.).

[0027] In this disclosure, 2~20 "Alkenyl" means a straight or branched chain hydrocarbon group containing two or more carbon atoms and having at least one unsaturated double bond, including, but not limited to, for example, ethenyl, propenyl, isopropenyl, butenyl, pentenyl, hexenyl, and the like.

[0028] In this disclosure, 3~20"Cycloalkenyl" means a monocyclic or bicyclic hydrocarbon group containing three or more carbon atoms and having at least one unsaturated double bond, including, but not limited to, for example, cyclopropenyl, cyclobutenyl, cyclohexenyl, etc.

[0029] In this disclosure, 2~20 "Alkynyl" means a straight or branched chain hydrocarbon group containing two or more carbon atoms and having at least one unsaturated triple bond (including, but not limited to, acetinyl, propargyl, etc.).

[0030] In this disclosure, 1~20 "Alkoxy" means a group of the formula "-OC 1~20 "alkyl" means a group having the structure "alkyl" (including, but not limited to, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, etc.).

[0031] In this disclosure, "divalent C 1~20 The "hydrocarbon portion" is C 1~20 It means a hydrocarbon moiety with two bonds, which is formed by removing one hydrogen atom from a hydrocarbon group. For example, C 1~20 If the hydrocarbon group is a methyl group (-CH3), the corresponding divalent C 1~20 The hydrocarbon portion is methylene (-CH2-).

[0032] In the present disclosure, "C optionally substituted with one or more substituents" 1~20 "hydrocarbon group" or "divalent C optionally substituted with one or more substituents" 1~20 "Hydrocarbon moiety" refers to a hydrocarbon group or a hydrocarbon moiety in which one or more hydrogen atoms may or may not be substituted with any substituent, C 1~20 Hydrocarbon group or divalent C 1~20 Such optional substituents include, but are not limited to, C as defined in the present disclosure. 1~20Examples of such groups include hydrocarbon groups, amino groups (including primary amino groups and secondary amino groups), hydroxy groups, thiol groups, halogen groups (for example, fluorine, chlorine, bromine, iodine, etc.), carbonyl groups, and aldehyde groups.

[0033] According to one embodiment of the present disclosure, R1 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably methylene or ethylene, which may be substituted with one or more substituents.

[0034] According to one embodiment of the present disclosure, Z1 is a bond.

[0035] According to one embodiment of the present disclosure, Z1 is NR2. According to a preferred embodiment of the present disclosure, Z1 is NH.

[0036] According to one embodiment of the present disclosure, R3 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably ethylene or propylene, which may be substituted with one or more substituents.

[0037] According to one embodiment of the present disclosure, R4 is hydrogen or C 1~20 Alkyl (preferably C optionally substituted with one or more substituents) 1~10 alkyl, more preferably C optionally substituted with one or more substituents 1~5 alkyl, more preferably methyl or ethyl which may be substituted with one or more substituents, even more preferably methyl which may be substituted with one or more substituents).

[0038] According to one embodiment of the present disclosure, R1 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably methylene or ethylene optionally substituted by one or more substituents), and R3 is C optionally substituted by one or more substituents. 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably ethylene or propylene optionally substituted with one or more substituents), and R4 is hydrogen or C 1~20 Alkyl (preferably C optionally substituted with one or more substituents) 1~10 alkyl, more preferably C optionally substituted with one or more substituents 1~5 alkyl, more preferably methyl or ethyl which may be substituted with one or more substituents, even more preferably methyl which may be substituted with one or more substituents).

[0039] According to one embodiment of the present disclosure, R1 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably methylene or ethylene optionally substituted by one or more substituents), Z1 is NR2 (preferably NH), R3 is C optionally substituted by one or more substituents, 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5alkylene, more preferably ethylene or propylene optionally substituted with one or more substituents), and R4 is hydrogen or C 1~20 Alkyl (preferably C optionally substituted with one or more substituents) 1~10 alkyl, more preferably C optionally substituted with one or more substituents 1~5 alkyl, more preferably methyl or ethyl which may be substituted with one or more substituents, even more preferably methyl which may be substituted with one or more substituents).

[0040] According to a preferred embodiment of the present disclosure, the amino group-containing group represented by formula (I) is as follows: [ka] The compound contains at least one selected from the group consisting of:

[0041] According to a preferred embodiment of the present disclosure, the amino group-containing group represented by formula (I) is as follows: [ka] The compound contains at least one selected from the group consisting of:

[0042] According to a preferred embodiment of the present disclosure, the amino group-containing group represented by formula (I) is as follows: [ka] At least includes.

[0043] The amount of the amino group-containing group represented by formula (I) contained in the precious metal-adsorbing material of the present disclosure is not particularly limited, but may be, for example, about 0.01 to about 5 mmol, preferably about 0.1 to about 4 mmol, and more preferably about 0.5 to about 3 mmol, based on 1 g of silica carrier.

[0044] The total amount of amino groups (total amount of primary amino groups, secondary amino groups, and tertiary amino groups) contained in the precious metal-adsorbing material of the present disclosure is not particularly limited, but may be, for example, about 0.01 to about 10 mmol, preferably about 0.2 to about 8 mmol, and more preferably about 1 to about 6 mmol, based on 1 g of silica carrier. The amount of primary amino groups contained in the precious metal-adsorbing material of the present disclosure is not particularly limited, but may be, for example, about 0.01 to about 5 mmol, preferably about 0.1 to about 4 mmol, and more preferably about 0.5 to about 3 mmol, based on 1 g of silica carrier. Note that when the precious metal-adsorbing material of the present disclosure also contains an amino group-containing group represented by formula (II) described below, the amount of amino groups refers to the sum of the amino groups derived from the amino group-containing group represented by formula (I) and the amino group-containing group represented by formula (II).

[0045] [Amino group-containing group represented by formula (II)] According to one embodiment of the present disclosure, the noble metal-adsorbing material of the present disclosure is characterized in that the silica carrier is an amino group-containing group represented by formula (II): [ka] (In the formula, R5 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, Z2 is a bond or NR6; R6 is hydrogen or C optionally substituted with one or more substituents. 1~20 is a hydrocarbon group, R7 is a divalent C optionally substituted with one or more substituents. 1~20 (the hydrocarbon portion) In the noble metal adsorption material of the present disclosure, it is advantageous that the silica carrier is further modified with an amino group-containing group represented by formula (II) in order to exhibit better noble metal adsorption properties.

[0046] According to one embodiment of the present disclosure, R5 is a C 1~20Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably methylene or ethylene, which may be substituted with one or more substituents.

[0047] According to one embodiment of the present disclosure, Z2 is a bond.

[0048] According to one embodiment of the present disclosure, Z2 is NR6. According to a preferred embodiment of the present disclosure, Z2 is NH.

[0049] According to one embodiment of the present disclosure, R7 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably ethylene or propylene, which may be substituted with one or more substituents.

[0050] According to one embodiment of the present disclosure, R5 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably methylene or ethylene optionally substituted by one or more substituents), and R7 is C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably ethylene or propylene, which may be substituted with one or more substituents.

[0051] According to one embodiment of the present disclosure, R5 is a C 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably methylene or ethylene optionally substituted with one or more substituents, Z2 is NR2 (preferably NH), and R7 is C optionally substituted with one or more substituents. 1~20 Alkylene (preferably C, optionally substituted with one or more substituents) 1~10 alkylene, more preferably C optionally substituted with one or more substituents 1~5 alkylene, more preferably ethylene or propylene, which may be substituted with one or more substituents.

[0052] According to a preferred embodiment of the present disclosure, the amino group-containing group represented by formula (II) is as follows: [ka] The compound contains at least one selected from the group consisting of:

[0053] According to a preferred embodiment of the present disclosure, the amino group-containing group represented by formula (II) is as follows: [ka] The compound contains at least one selected from the group consisting of:

[0054] According to a preferred embodiment of the present disclosure, the amino group-containing group represented by formula (II) is as follows: [ka] At least includes.

[0055] The amount of the amino group-containing group represented by formula (II) contained in the precious metal-adsorbing material of the present disclosure is not particularly limited, but may be, for example, about 0.01 to about 5 mmol, preferably about 0.1 to about 4 mmol, and more preferably about 0.5 to about 3 mmol, based on 1 g of silica carrier.

[0056] The molar ratio of the amino group-containing groups represented by formula (I) to the amino group-containing groups represented by formula (II) on the silica support of the precious metal adsorption material of the present disclosure (amino group-containing groups represented by formula (II) / amino group-containing groups represented by formula (I)) is not particularly limited as long as the object of the present disclosure can be achieved. From the viewpoint of exhibiting better precious metal adsorption properties, the molar ratio (amino group-containing groups represented by formula (II) / amino group-containing groups represented by formula (I)) is preferably 0.1 to 10, more preferably 0.2 to 3, and even more preferably 0.3 to 2.

[0057] [Method for producing a precious metal adsorption material] The noble metal-adsorbing material of the present disclosure is not particularly limited as long as it is a method capable of grafting an amino group-containing group represented by formula (I) onto a silica support. According to one embodiment of the present disclosure, there is provided a method for producing the noble metal-adsorbing material, comprising the steps of: [ka] wherein R, Z, R, and R are as defined above, and each R is independently a C 1~20 (hydrocarbon radical) and a silica support (also referred to as the "contacting step" in the present disclosure). A method is provided, comprising:

[0058] <Compound represented by formula (III)> According to one embodiment of the present disclosure, preferred aspects of R1, Z1, R3 and R4 are as described above in formula (I).

[0059] According to one embodiment of the present disclosure, each R is independently a C optionally substituted with one or more substituents. 1~20 an alkyl group (preferably C which may be substituted with one or more substituents); 1~10 alkyl, more preferably methyl, ethyl, propyl, isopropyl or butyl, optionally substituted with one or more substituents, even more preferably methyl, optionally substituted with one or more substituents).

[0060] According to a preferred embodiment of the present disclosure, the compound represented by formula (III) comprises at least one selected from the group consisting of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, and N-(2-aminoethyl)-3-aminopropyldiethoxysilane. According to a preferred embodiment of the present disclosure, the compound represented by formula (III) comprises at least N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane.

[0061] According to one embodiment of the present disclosure, the contacting step comprises contacting a compound represented by formula (IV): [ka] wherein R, Z, and R are as defined above, and each R is independently a C group optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) further contacting the

[0062] <Compound represented by formula (IV)> According to one embodiment of the present disclosure, preferred aspects of R5, Z2 and R7 are as described above in formula (II).

[0063] According to one embodiment of the present disclosure, each R9 is independently a C 1~20 an alkyl group (preferably C which may be substituted with one or more substituents); 1~10 alkyl, more preferably methyl, ethyl, propyl, isopropyl or butyl, optionally substituted with one or more substituents, even more preferably methyl, optionally substituted with one or more substituents).

[0064] According to a preferred embodiment of the present disclosure, the compound represented by formula (IV) comprises at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane. According to a preferred embodiment of the present disclosure, the compound represented by formula (IV) comprises at least N-(2-aminoethyl)3-aminopropyltrimethoxysilane.

[0065] <Solvent> The contacting step is usually carried out in the presence of a solvent. Examples of the solvent include, but are not limited to, organic solvents such as aromatic hydrocarbons (e.g., toluene, xylene, etc.); saturated aliphatic hydrocarbons (e.g., pentane, hexane, paraffin, etc.); and alcohols (e.g., methanol, ethanol, etc.). These may be used alone or in combination. The ratio of the solvent to the silica carrier can be appropriately adjusted by those skilled in the art. If the amount of the solvent is too small, the silica carrier and the organosilicon compound may not be easily mixed. If the amount of the solvent is too large, the concentration of the organosilicon compound in the solvent may be diluted, requiring a long time for grafting of the amino group-containing group represented by formula (I) and / or, if present, the amino group-containing group represented by formula (III). The ratio of the solvent to the silica carrier (solvent:silica carrier) is, for example, about 1:10 to about 100:1 by volume, preferably about 1:5 to about 1:50, and more preferably about 1:1 to about 1:10.

[0066] <Temperature, time> The temperature at which the silica support is mixed with the compound represented by formula (III) and, if present, the compound represented by formula (IV) is not particularly limited, as long as it is a temperature at which the amino group-containing group represented by formula (I) and, if present, the amino group-containing group represented by formula (II) are grafted onto the silica support. The mixing temperature may be, for example, about 0 to about 200°C, preferably about 30 to about 150°C, and more preferably about 50 to about 120°C. Furthermore, one skilled in the art can appropriately adjust the reaction time, taking into consideration the temperature and the degree of grafting of the desired amino group-containing group represented by formula (I) and, if present, the amino group-containing group represented by formula (II) with the compound represented by formula (IV).

[0067] When the compound represented by formula (IV) is also contacted in the contacting step, the molar ratio of the compound represented by formula (III) to the compound represented by formula (IV) (compound represented by formula (IV) / compound represented by formula (III)) can be appropriately adjusted depending on the desired precious metal adsorption material. From the viewpoint of producing a precious metal adsorption material exhibiting better precious metal adsorption properties, the molar ratio (compound represented by formula (IV) / compound represented by formula (III)) is preferably 0.1 to 10, more preferably 0.2 to 3, and even more preferably 0.3 to 2. The molar ratio of the compound represented by formula (III) to the compound represented by formula (IV) in the contacting step is considered to correspond to the molar ratio of the amino group-containing group represented by formula (I) to the amino group-containing group represented by formula (II) that is graphed on the obtained precious metal adsorption material.

[0068] [Uses of precious metal adsorption materials] The precious metal adsorption material of the present disclosure is capable of adsorbing a precious metal element in a composition (e.g., in a solvent). The precious metal element may have any valence (i.e., it may be a low valence or a high valence). In this disclosure, "low valence" means that the valence is less than 2. In this disclosure, "high valence" means that the valence is 2 or more (e.g., 2 or 3).

[0069] In the present disclosure, the precious metal element may be a radioactive isotope. Furthermore, the precious metal element may be a free ion in the composition or may form a complex compound. The precious metal adsorption material of the present disclosure is advantageous in that it exhibits good adsorption even for precious metal elements in complex compounds. Therefore, according to one embodiment of the present disclosure, the precious metal adsorption material of the present disclosure is intended for adsorption of precious metal elements contained in complex compounds.

[0070] Examples of noble metal elements include, but are not limited to, platinum group elements such as ruthenium, rhodium, palladium, osmium, iridium, and platinum; gold; silver; and rhenium. The noble metal element is preferably a platinum group element, and particularly preferably ruthenium, rhodium, palladium, or platinum. Therefore, the noble metal adsorption material of the present disclosure can be advantageously used, in particular, for adsorbing platinum group elements (preferably ruthenium, rhodium, palladium, and / or platinum) in a composition (e.g., in a solvent). Therefore, according to one embodiment of the present disclosure, the noble metal adsorption material of the present disclosure is intended for adsorbing platinum group elements (preferably ruthenium, rhodium, palladium, and / or platinum).

[0071] Furthermore, according to one embodiment of the present disclosure, the noble metal adsorption material of the present disclosure can be used as a scavenger for noble metal elements.

[0072] Examples of methods for adsorbing precious metal elements to the precious metal adsorption material of the present disclosure include mixing a composition (e.g., a solution) containing precious metal elements with the precious metal adsorption material of the present disclosure, and then leaving the mixture to stand, stirring, mixing, etc. for a desired time and temperature. By separating (e.g., filtering) the precious metal adsorption material of the present disclosure by a desired method, it is possible to recover the precious metal elements present in the composition. The recovered precious metal elements can be reused by a desired method.

[0073] The present disclosure encompasses the following. [1] The silica support is an amino group-containing group represented by formula (I): [ka] (In the formula, R1 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, Z1 is a bond or NR2; R2 is hydrogen or C optionally substituted with one or more substituents. 1~20 is a hydrocarbon group, R3 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, R4 is hydrogen or C optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) At least one precious metal adsorbent material modified with [2] R1 is C 1~20 The noble metal adsorption material according to [1], wherein the alkylene is alkylene. [3] The noble metal adsorption material according to [1] or [2], wherein Z1 is NR2. [4] R3 is C 1~20 The noble metal-adsorption material according to any one of [1] to [3], wherein the alkylene is alkylene. [5] R4 is C 1~20 The noble metal-adsorbing material according to any one of [1] to [4], wherein the noble metal-adsorbing material is alkyl. [6] The silica support is an amino group-containing group represented by formula (II): [ka] (In the formula, R5 is a divalent C optionally substituted with one or more substituents. 1~20 is a hydrocarbon moiety, Z2 is a bond or NR6; R6 is hydrogen or C optionally substituted with one or more substituents. 1~20 is a hydrocarbon group, R7 is a divalent C optionally substituted with one or more substituents. 1~20 (the hydrocarbon portion) The noble metal-adsorbing material according to any one of [1] to [5], further modified with [7] R5 is C 1~20 The noble metal-adsorbing material according to [6], wherein the alkylene is alkylene. [8] The precious metal adsorption material according to [6] or [7], wherein Z2 is NR6. [9] R7 is C 1~20 The noble metal-adsorption material according to any one of [6] to [8], wherein the alkylene is alkylene.

[10] The noble metal adsorption material according to any one of [6] to [9], wherein the molar ratio of the amino group-containing group represented by formula (I) to the amino group-containing group represented by formula (II) on the silica support (amino group-containing group represented by formula (II) / amino group-containing group represented by formula (I)) is 0.1 to 10.

[11] The noble metal-adsorbing material according to any one of [1] to

[10] , wherein the silica carrier has an average particle diameter (D10) of 10 to 300 μm.

[12] A method for producing the precious metal-adsorbing material according to any one of [1] to

[11] , Compounds of formula (III): [ka] wherein R1, Z1, R3 and R4 are as defined in claim 1, and each R8 is independently C optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) contacting the silica support with A method comprising:

[13] The method according to

[12] , wherein the compound represented by formula (III) comprises at least one selected from the group consisting of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, and N-(2-aminoethyl)-3-aminopropyldiethoxysilane.

[14] In the contacting step, a compound represented by formula (IV): [ka] wherein R5, Z2 and R7 are as defined in claim 1, and each R9 is independently C optionally substituted with one or more substituents. 1~20 (hydrocarbon radical) The method of

[12] or

[13] , further comprising contacting the

[15] The method according to

[14] , wherein the compound represented by formula (IV) includes at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane. [Example]

[0074] The method of the present disclosure will be described in more detail below using examples. However, the following examples are not intended to limit the method of the present disclosure in any way. Unless otherwise specified, percentages and ratios described herein are by mass. Furthermore, unless otherwise specified, units and measurement methods described herein are in accordance with the provisions of the Japanese Industrial Standards (JIS).

[0075] [Example 1: Production of precious metal adsorption material 1] In a reaction vessel filled with nitrogen gas, 850 mL of denatured alcohol and a silica support (specific surface area: 750 m 2400 g (dry weight) of silica gel (silica carrier) with a pore volume of 1.24 ml / g, average pore diameter of 6.6 nm, and average particle diameter (D10): 62 μm was mixed with 0.58 mol of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (Shin-Etsu Chemical Co., Ltd.), and the mixture was stirred for 1 hour while heating to 80°C. The resulting solution was evaporated under reduced pressure to remove the solvent, yielding the noble metal adsorbent of Example 1. The results of CHN elemental analysis and ICP atomic emission spectroscopy confirmed that primary amino groups had been grafted onto the silica carrier (primary amino groups per 1 g of silica carrier: 1 mmol).

[0076] [Example 2: Production of precious metal adsorption material 2] The same procedure was carried out as in Example 1, except that the amount of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane was changed to 1.16 mol, to obtain the precious metal adsorption material of Example 2. The results of CHN elemental analysis and ICP emission spectroscopy confirmed that primary amino groups had been grafted onto the silica carrier (primary amino groups per 1 g of silica carrier: 2 mmol).

[0077] [Example 3: Production of precious metal adsorption material 3] The same procedure was carried out as in Example 1, except that 0.29 moles of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and 0.29 moles of N-(2-aminoethyl)3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) were used instead of 0.58 moles of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, to obtain the precious metal adsorption material of Example 3 (molar ratio of N-(2-aminoethyl)3-aminopropyltrimethoxysilane / N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane: 1).

[0078] [Example 4: Production of precious metal adsorption material 4] The same procedure was carried out as in Example 3, except that the amount of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane was changed to 0.58 moles and the amount of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane was changed to 0.58 moles, thereby obtaining the precious metal adsorption material of Example 4 (molar ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane / N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane: 1).

[0079] [Comparative Example 1: Production of precious metal adsorption material 5] The same procedure was carried out as in Example 1, except that N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane was used instead of N-(2-aminoethyl)3-aminopropyltrimethoxysilane, to obtain the precious metal adsorption material of Comparative Example 1.

[0080] [Test Example 1: Precious Metal Adsorption Evaluation 1 (PT-VTS-IPA Solution)] 15 mL of denatured alcohol, 0.015 g of 3% PT-VTS-IPA solution (divinyltetramethyldisiloxane platinum complex isopropyl alcohol solution) manufactured by N.E. Chemcat Corporation, and 0.375 g of each precious metal adsorption material were mixed in a 20 mL sample tube and stirred for 1 hour. The precious metal adsorption material was then filtered, and the amount of precious metal element remaining in the filtrate was evaluated by ICP atomic emission spectroscopy. The mass of precious metal element adsorbed per 1 g of precious metal adsorption material was then calculated using the following formula. The results are shown in Table 1.

[0081]

number

[0082] [Test Example 2: Evaluation of Precious Metal Adsorption 2 (PdCl2(PhCN)2_PhCN Solution)] 15 g of a 1000 ppm solution of [dichlorobis(benzonitrile)palladium(II)] dissolved in benzonitrile and 100 mg of each precious metal adsorption material were mixed in a 20 mL sample tube and stirred for 24 hours. Thereafter, the mass of the precious metal element adsorbed per 1 g of the precious metal adsorption material was calculated using the same method as in Test Example 1. The results are shown in Table 1.

[0083] [Test Example 3: Evaluation of Precious Metal Adsorption 3 (Na2PdCl4 Solution)] In a 20 mL sample tube, 15 g of a 1000 ppm aqueous solution of sodium tetrachloropalladate (II) and 100 mg of each precious metal adsorption material were mixed and stirred for 24 hours. Thereafter, the mass of the precious metal element adsorbed per 1 g of the precious metal adsorption material was calculated using the same method as in Test Example 1. The results are shown in Table 1.

[0084] [Table 1]

[0085] From the results of Test Examples 1 to 3, the precious metal-adsorbing material of Example 1 (i.e., the precious metal-adsorbing material grafted with amino group-containing groups represented by formula (I)) exhibited superior precious metal adsorption for a wide range of precious metals compared to the precious metal-adsorbing material of Comparative Example 1 (i.e., the precious metal-adsorbing material grafted solely with amino group-containing groups represented by formula (II)). The precious metal-adsorbing material of Example 1 exhibited superior precious metal adsorption to that of Comparative Example 1, even though the molar amount of the grafted functional groups is thought to be equivalent to that of the precious metal-adsorbing material of Comparative Example 1. This is a completely unexpected result. Furthermore, from the results of Test Examples 2 and 3, the precious metal adsorption materials of Examples 3 and 4 (i.e., precious metal adsorption materials grafted with both amino group-containing groups represented by formula (I) and amino group-containing groups represented by formula (II)) each exhibited even better precious metal adsorption than the precious metal adsorption materials of Examples 1 and 2 (i.e., precious metal adsorption materials grafted with only amino group-containing groups represented by formula (I)). The precious metal adsorption materials of Examples 3 and 4 each exhibited better precious metal adsorption than Examples 1 and 2, respectively, despite the molar amount of the grafted functional groups being considered to be equivalent to those of the precious metal adsorption materials of Examples 1 and 2. This, too, is a completely unexpected result.

[0086] Without being bound by theory, it is believed that compounds represented by formula (III) (e.g., silane coupling agents having dialkoxysilyl groups) undergo two-dimensional crosslinking upon hydrolysis and condensation, which reduces self-polymerization between compounds represented by formula (III) and the amount of multilayer support on the silica carrier. Therefore, it is believed that a precious metal adsorption material in which the silica carrier is modified with amino group-containing groups represented by formula (I) has a reduced proportion of amino groups that cannot come into contact with the precious metal to be adsorbed, compared to a precious metal adsorption material in which the silica carrier is modified with amino group-containing groups represented by formula (II). Without being bound by theory, it is believed that by using a compound represented by formula (III) in combination with a compound represented by formula (IV) (e.g., a silane coupling agent having a trialkoxysilyl group), the amino group-containing group represented by formula (II) serves as a polyfunctional branching agent, thereby adequately adjusting the contact with the support and the functional group density. Therefore, it is believed that by using a compound represented by formula (III), excellent noble metal adsorption properties can be obtained even for targets that are poorly adsorbed by a compound represented by formula (IV) (in other words, an amino group-containing group represented by formula (II)). Furthermore, it is believed that by using a compound represented by formula (III) in combination with a compound represented by formula (IV) (in other words, by forming a noble metal adsorption material in which the amino group-containing group represented by formula (I) and the amino group-containing group represented by formula (II) are graphed), noble metal adsorption properties superior to those obtained by using each compound alone can be obtained for a wide range of noble metals.

Claims

1. The silica support is an amino group-containing group represented by formula (I): 【Chemistry 1】 (In the formula, R １ is a divalent C optionally substituted with one or more substituents １～２０ is a hydrocarbon moiety, Z １ is a bond or NR ２ and R ２ is hydrogen or C optionally substituted with one or more substituents １～２０ is a hydrocarbon group, R ３ is a divalent C optionally substituted with one or more substituents １～２０ is a hydrocarbon moiety, R ４ is hydrogen or C optionally substituted with one or more substituents １～２０ hydrocarbon group) At least one precious metal adsorbent material modified with

2. R １ is C １～２０ The noble metal adsorption material according to claim 1 , which is an alkylene.

3. Z １ NR ２ The noble metal adsorption material according to claim 1 ,

4. R ３ is C １～２０ The noble metal adsorption material according to claim 1 , which is an alkylene.

5. R ４ is C １～２０ The noble metal adsorption material according to claim 1 , wherein the noble metal adsorption material is an alkyl.

6. The silica support is an amino group-containing group represented by formula (II): 【Chemistry 2】 (In the formula, R ５ is a divalent C optionally substituted with one or more substituents １～２０ is a hydrocarbon moiety, Z ２ is a bond or NR ６ and R ６ is hydrogen or C optionally substituted with one or more substituents １～２０ is a hydrocarbon group, R ７ is a divalent C optionally substituted with one or more substituents １～２０ hydrocarbon portion) The precious metal adsorption material according to claim 1 , further modified with

7. R ５ is C １～２０ The noble metal adsorption material according to claim 6 , which is an alkylene.

8. Z ２ NR ６ The noble metal-adsorbing material according to claim 6,

9. R ７ is C １～２０ The noble metal adsorption material according to claim 6 , which is an alkylene.

10. 7. The noble metal-adsorption material according to claim 6, wherein the molar ratio of the amino group-containing groups represented by formula (I) to the amino group-containing groups represented by formula (II) on the silica support (amino group-containing groups represented by formula (II) / amino group-containing groups represented by formula (I)) is 0.1 to 10.

11. 2. The noble metal adsorption material according to claim 1, wherein the silica carrier has an average particle diameter (D10) of 10 to 300 μm.

12. A method for producing the precious metal-adsorbing material according to any one of claims 1 to 11, Compounds represented by formula (III): 【Transformation 3】 (In the formula, R １ , Z １ , R ３ and R ４ is as defined in claim 1, and each R ８ each independently represents a C optionally substituted with one or more substituents; １～２０ hydrocarbon group) contacting the silica support with A method comprising:

13. The method of claim 12, wherein the compound represented by formula (III) comprises at least one selected from the group consisting of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, and N-(2-aminoethyl)-3-aminopropyldiethoxysilane.

14. In the contacting step, a compound represented by formula (IV): 【Chemistry 4】 (In the formula, R ５ , Z ２ and R ７ is as defined in claim 1, and each R ９ each independently represents a C optionally substituted with one or more substituents; １～２０ hydrocarbon group) 13. The method of claim 12, further comprising contacting

15. The method according to claim 14, wherein the compound represented by formula (IV) comprises at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane.

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