Hydrogel, dried hydrogel, catalyst, method for producing hydrogel, and method for producing catalyst

Abstract

Provided is a hydrogel for supporting metal species that is suitable for supporting metal species. [Solution] The provided hydrogel is a hydrogel for supporting metal species, which comprises a network A of first polymer chains, which are polymer chains of a precursor having vinyl polymerization properties, and a network B of second polymer chains having siloxane bonds in the main chain. The provided hydrogel may further comprise a metal species. The hydrogel further comprising a metal species may be used as a catalyst. One example of the catalyst is a hydrosilylation catalyst.

Description

[Technical Field]

[0001] The present invention relates to a hydrogel, a dried hydrogel, and a catalyst. The present invention also relates to a method for producing a hydrogel and a method for producing a catalyst. [Background technology]

[0002] Hydrogels are one type of gel. The molecular chain network of a typical hydrogel is usually in a state swollen with water. It is thought that water is contained in the hydrogel in a state where it is compatible with the molecular chains. A typical example of a hydrogel is silicone hydrogel, which is mainly used for contact lenses. Patent Document 1 discloses a silicone hydrogel obtained by polymerizing a polymerization solution containing silicone (meth)acrylamide monomers. The silicone hydrogel of Patent Document 1 has a network of polymer chains formed by polymerization of silicone (meth)acrylamide and a copolymerizable monomer. This polymer chain has a main chain consisting of -CC- bonds. Silicon (Si) atoms are located only in the side chains of the polymer chains, without forming a network separate from the polymer chains.

[0003] Hydrosilylation, the addition reaction of hydrosilanes to carbon-carbon unsaturated bonds, is an industrially important catalytic reaction used to synthesize organosilicon materials such as silicone materials and silane coupling agents. A platinum catalyst is typically used for hydrosilylation. The Karstedt catalyst is a well-known example. However, the Karstedt catalyst is a homogeneous catalyst, making it difficult to reuse, and the platinum after the reaction is discarded without being recovered. It has been reported that the amount of platinum discarded after hydrosilylation reaches 5.6 tons per year. In contrast, Patent Document 2, Non-Patent Document 1, and Non-Patent Document 2 disclose a heterogeneous catalyst technology in which transition metal complexes or platinum nanoparticles are supported on the surface of a porous gel. In Non-Patent Document 1 and Non-Patent Document 2, hard silica gel particles are used in the porous gel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-197196 [Patent Document 2] Japanese Patent Publication No. 2022-110295 [Non-patent literature]

[0005] [Non-Patent Document 1] Srinivas Komati et al., “Leach-resistant Pt nanoparticles on a silica support serving as a clean, efficient, and recyclable catalyst for solvent-free hydrosilylation”, Green Chem., 2021, 23, 9071-9077 [Non-patent document 2] Susannah A. Miller and Damien Guironnet, “Tunable Latency of Hydrosilylation Catalyst by Ligand Density on Nanoparticle Supports”, Angew. Chem. Int. Ed. 2023, 62, e202214267 Summary of the Invention [Problem to be solved by the invention]

[0006] It is conceivable to use hydrogel as a carrier for metal species such as catalysts. Patent Document 2, Non-Patent Document 1, and Non-Patent Document 2 do not consider the use of hydrogel as a carrier for metal species.

[0007] An object of the present invention is to provide a hydrogel for supporting metal species that is suitable for supporting metal species. [Means for solving the problem]

[0008] [1] The hydrogel according to an embodiment of the present invention comprises: a first polymer chain network A which is a polymer chain of a precursor having vinyl polymerizability; a second polymer chain network B having a siloxane bond in the main chain; Including, For carrying metal species. [2] In the hydrogel described in [1] above, the precursor may be at least one selected from the group consisting of monosubstituted ethylene, disubstituted ethylene, and diene compounds. [3] In the hydrogel described in [1] or [2] above, the precursor may be at least one selected from the group consisting of (meth)acrylic acid, (meth)acrylate, (meth)acrylamide, styrene, styrene derivatives, and isoprene. [4] In the hydrogel according to any one of the above [1] to [3], the second polymer chain may be a polysiloxane chain. [5] In the hydrogel according to any one of the above [1] to [4], the hydrogel may not have a bonding point that bonds the network A and the network B together by a covalent bond. [6] In the hydrogel according to any one of the above [1] to [5], the hydrogel may not have macropores. [7] The hydrogel according to any one of [1] to [6] above may further contain a metal species. [8] In the hydrogel according to the above [7], the metal species may be coordinated to at least one selected from the group consisting of the network A and the network B. [9] In the hydrogel according to the above [7] or [8], the metal species may be a first transition series element, a second transition series element, a third transition series element, or an alloy thereof.

[10] In the hydrogel described in any one of [7] to [9] above, the metal species may be Pd, Pt, Ag, Au, Rh, Ir, Re, Ru, Mn, Fe, Co, Ni, or Cu, or an alloy thereof.

[11] A dried hydrogel according to an embodiment of the present invention is a dried hydrogel according to any one of the above [1] to

[10] .

[12] The catalyst according to an embodiment of the present invention comprises: The hydrogel includes the hydrogel described in any one of [7] to

[10] above.

[13] The catalyst described in

[12] above may be a hydrosilylation catalyst.

[14] A method for producing a hydrogel according to an embodiment of the present invention includes: A solution system including a first precursor having vinyl polymerizability and a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, forming a hydrogel for supporting metal species, the hydrogel including the network A and the network B;

[15] In the manufacturing method described in

[14] above, the solvent of the solution system may be hydrophilic.

[16] In the manufacturing method according to the above

[14] or

[15] , the solution system may further contain a metal species, and the hydrogel may be formed by further containing the metal species.

[17] The manufacturing method described in

[16] above may further comprise reducing the metal species contained in the formed hydrogel.

[18] A method for producing a catalyst according to an embodiment of the present invention comprises: 1. A method for producing a catalyst comprising a hydrogel containing a metal species, comprising: A solution system including a first precursor having vinyl polymerizability, a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, and a metal species, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, forming a hydrogel comprising the network A and the network B, and the metal species. [Effects of the Invention]

[0009] According to an embodiment of the present invention, a hydrogel for supporting metal species that is suitable for supporting metal species can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating the hydrogel of the present invention. [Figure 2] FIG. 1 is a diagram illustrating the assumed coordination state of metal species in an example of the hydrogel of the present invention containing metal species. DETAILED DESCRIPTION OF THE INVENTION

[0011] <<1. Hydrogel>> A hydrogel 1 (first hydrogel) according to one embodiment of the present invention includes a network A of first polymer chains 11, which are polymer chains of a vinyl-polymerizable precursor (first precursor), and a network B of second polymer chains 12 having siloxane bonds in their main chains (see FIG. 1). The first polymer chains 11 and the second polymer chains 12 are different molecular chains. Each of the first polymer chains 11 and the second polymer chains 12 may or may not have branches. Each of Network A and Network B may be a one-dimensional, two-dimensional, or three-dimensional network. Branching of the polymer chains contributes to the formation of two-dimensional and three-dimensional networks. At least two types of networks selected from the group consisting of one-dimensional, two-dimensional, and three-dimensional may coexist within the hydrogel 1. Network A and Network B are typically entangled with each other. Each of Network A and Network B may have a mesh structure. The hydrogel 1 typically contains a liquid 13. The hydrogel 1 in FIG. 1 contains water as the liquid 13, as is the name of conventionally used hydrogels. However, as will be described later, the liquid 13 that the hydrogel 1 of this embodiment may contain is not limited to water. The liquid 13 is usually contained in the hydrogel 1 in a state where it has affinity with both the first polymer chains 11 and the second polymer chains 12. The liquid 13 may be held within the entangled structure of network A and network B. The hydrogel 1 is in a state swollen by the liquid 13. When the portion of the gel body formed by the network of molecular chains is expressed as the skeleton of the gel body, the liquid 13 can also be expressed as being contained within the skeleton of the hydrogel 1. In the hydrogel 1 of this embodiment, the liquid 13 may be contained only within the skeleton.

[0012] The inclusion of multiple networks with different properties, such as Network A and Network B, can contribute to improved properties compared to when only one type of network is included. Potentially improved properties include, for example, mechanical properties such as elastic modulus and strength, or swelling properties in liquid 13. Improved swelling properties in liquid 13 include swelling in both hydrophilic and hydrophobic liquids, and improving the balance of swelling properties between liquids with different properties. These improved properties can contribute to, for example, increasing the flexibility of applications for hydrogels containing metal species.

[0013] <1-1. First Polymer Chain> The first polymer chain 11 is a polymer chain of a first precursor having vinyl polymerizability. The first precursor has a vinyl polymerizable group. The vinyl polymerizable group is a group capable of forming a carbon-carbon single bond (-CC- bond) constituting the main chain of the polymer chain, and is a group containing a carbon-carbon double bond. Examples of the vinyl polymerizable group are a vinyl group and a (meth)acrylic group. However, the vinyl polymerizable group is not limited to the above examples. Note that (meth)acrylic means acrylic and methacrylic. (Meth)acrylate means acrylate and methacrylate. (Meth)acrylamide means acrylamide and methacrylamide.

[0014] The first precursor is, for example, at least one selected from the group consisting of monosubstituted ethylene, disubstituted ethylene, and diene compounds. Examples of monosubstituted ethylenes include styrene, styrene derivatives, vinyl alcohol, acrylic acid, acrylonitrile, vinyl esters such as acrylic acid esters (acrylates) and vinyl acetate, acrylamide and its derivatives, and vinyl halides such as vinyl chloride. Examples of disubstituted ethylenes include methacrylic acid, methacrylic acid esters (methacrylates), methacrylamide and its derivatives, and vinylidene halides such as vinylidene chloride and vinylidene fluoride. Examples of diene compounds include isoprene, 1,2-butadiene, 1,3-butadiene, divinylbenzene, and compounds in which at least a portion of the hydrogen atoms of the above diene compounds are substituted with substituents (hereinafter referred to as "diene derivatives"). Examples of the substituent that the styrene derivative may have include alkoxy groups such as methoxy and ethoxy groups, alkyl groups, phenyl groups, carboxyl groups, acyl groups, hydroxyl groups, amino groups, ester groups, cyano groups, nitro groups, sulfonyl groups, and halogen groups. Examples of the substituent that the diene derivative may have are the same as the examples of the substituent that the styrene derivative may have.

[0015] The first precursor may be at least one selected from the group consisting of (meth)acrylic acid, (meth)acrylate, (meth)acrylamide, styrene, a styrene derivative, and isoprene.

[0016] Examples of (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, vinyl (meth)acrylate, Examples of suitable PEGMA compounds include hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, diethylene glycol methyl ether (meth)acrylate, diethylaminoethyl (meth)acrylate, trimethylsilyl (meth)acrylate, poly(ethylene glycol) acrylate, and poly(ethylene glycol) methacrylate (PEGMA). PEGMA is a compound represented by the following formula (1). In formula (1), n ​​is, for example, 1 to 20,000. n may be 2 or more, 5 or more, 10 or more, 25 or more, 50 or more, 75 or more, 100 or more, 150 or more, 200 or more, 250 or more, or even 300 or more. n may be 15,000 or less, 10,000 or less, 8,000 or less, 6,000 or less, 5,000 or less, 4,000 or less, 3,000 or less, 2,000 or less, 1,500 or less, or even 1,000 or less. However, the (meth)acrylate that can be the first precursor is not limited to the above examples.

[0017] [ka]

[0018] Examples of (meth)acrylamides include N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N,N'-methylenebis(meth)acrylamide, N-[tris(3-acrylamidopropoxymethyl)methyl]acrylamide, N,N'-bis(2-acrylamidoethyl)acrylamide, N,N'-1,2-ethanediylbis{N-[2-(acryloylamino)ethyl]acrylamide}, and 4-[(3-methacrylamidopropyl)dimethylammonio]butane-1-sulfonic acid. (Meth)acrylamides that can be the first precursor are not limited to the above examples.

[0019] Examples of styrene derivatives are styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, and chloromethylstyrene. The styrene derivatives that can be the first precursor are not limited to the above examples.

[0020] The first precursor may be a multifunctional precursor. A multifunctional precursor has two or more vinyl polymerizable groups, or at least one vinyl polymerizable group and at least one other polymerizable group. Examples of multifunctional precursors include multifunctional acrylates such as divinylbenzene, ethylene glycol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate, and multifunctional methacrylates such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, and methacryloxyethyl phosphate. Multifunctional precursors that can be the first precursor are not limited to the above examples.

[0021] The first precursor may be maleic anhydride, fumaric anhydride, vinyl sulfonic acid, styrene sulfonic acid and vinyl alcohol.

[0022] The first precursor may be hydrophobic. The solubility of the hydrophobic first precursor in water (at 25°C) is less than 2% by weight. The first precursor may be hydrophilic. The solubility of the hydrophilic first precursor in water (at 25°C) is 2% by weight or more.

[0023] The first precursor may be an oligomer of each of the compounds exemplified above, as long as it can be polymerized to form the first polymer chains 11. The average degree of polymerization of the oligomer is, for example, 1000 or less, and may be 750 or less, 500 or less, 400 or less, 300 or less, 200 or less, or even 100 or less. The lower limit of the average degree of polymerization of the oligomer is usually 2 or more, and may be 5 or more, or even 10 or more.

[0024] The first precursor may be a molecular compound. Examples of the first precursor that is a molecular compound are as described above.

[0025] The first precursor is not limited to the above examples.

[0026] The first polymer chain 11 may be a polymer chain of one type of first precursor, or a copolymer chain of two or more types of first precursors.

[0027] The first polymer chain 11, which is the polymer chain of the first precursor, has a -C-C- bond in its main chain formed by polymerization of a vinyl polymerizable group. The main chain of the first polymer chain 11 may have a portion with two or more consecutive -C-C- bonds, or may be composed of repeated -C-C- bonds. The first polymer chain 11 is a polymer chain different from the second polymer chain 12. The first polymer chain 11 usually does not have a siloxane bond in its main chain.

[0028] The average degree of polymerization of the first precursor in the first polymer chains 11 is, for example, 1,000 to 1,000,000, and may be 1,000 to 100,000, or even 2,000 to 50,000.

[0029] The first polymer chains 11 may or may not have branches. The first polymer chains 11 may have a cross-linked structure connecting two or more first polymer chains 11. The cross-linked structure may be formed by a physical bond such as a hydrogen bond, or by a covalent bond.

[0030] The network A and the hydrogel 1 may contain two or more first polymer chains 11 with different configurations.

[0031] <1-2. Second Polymer Chain> The second polymer chain 12 has a siloxane bond (-O-Si-) in its main chain. The main chain of the second polymer chain 12 may have a portion where two or more siloxane bonds are continuous. The main chain of the second polymer chain 12 may be composed of repeated siloxane bonds; in other words, the second polymer chain 12 may be a polysiloxane chain. The second polymer chain 12 is a polymer chain different from the first polymer chain 11. The second polymer chain 12 does not have to have a -C-C- bond in its main chain.

[0032] The second polymer chains 12 may or may not have branches. The second polymer chains 12 may have a cross-linked structure connecting two or more second polymer chains 12. The cross-linked structure may be formed by a physical bond such as a hydrogen bond, or by a covalent bond.

[0033] The polysiloxane chain that can be the second polymer chain 12 may or may not have branches of siloxane bonds originating from the Si atoms that constitute the chain. The names Q unit, T unit, and D unit are known to those skilled in the art as structural units of polysiloxane chains. These terms refer to a unit having two branches originating from one Si atom, a unit having one branch, and a unit with no branches, respectively. The polysiloxane chain usually contains D units. The polysiloxane chain may contain T units, Q units, or both T units and Q units. The T units and Q units can contribute to the formation of a two- or more-dimensional network B.

[0034] The polysiloxane chain that can be the second polymer chain 12 may be a polyorganosiloxane chain. The polyorganosiloxane chain has a structural unit in which at least one, typically one, organo group is bonded to each Si atom constituting the chain. The organo group may be a monovalent group. The organo group may be a non-polymerizable group, in other words, a non-polymerizable group, or a polymerizable group. The organo group may constitute a terminal group branched from the polysiloxane chain using the Si atom as a branching point. The structural unit to which the organo group is bonded may be a D unit. The polyorganosiloxane chain may be a chain composed of D units.

[0035] Examples of organo groups include alkyl groups such as methyl, ethyl, propyl, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; aromatic groups such as ethenyl (vinyl), ethynyl, and phenyl; amino groups, mercapto groups, aldehyde groups, hydroxyl groups, halogen groups, cyano groups, carboxyl groups, isocyanate groups, silyl groups, fluoroalkyl groups in which at least one hydrogen atom in an alkyl group is substituted with a fluorine atom, sulfonic acid groups, and phosphine groups. The aromatic groups may have a condensed ring or a heteroaromatic ring. Other examples of organo groups include ether groups, epoxy groups, and polyethylene glycol groups. The organo group may be a carbene. The organo group may be a group formed by combining two or more of the above groups, and the group formed by the combination may be a monovalent group. Examples of groups formed by this combination include a 2-(aminoethylamino)propyl group, a 2-(2-aminoethylamino)ethylamino group, and a 2-(diphenylphosphino)ethyl group, although the organo group is not limited to the above examples.

[0036] The second polymer chains 12 can be formed, for example, by polymerization of a precursor (second precursor) having an Si atom. In other words, the second polymer chains 12 may be polymer chains of a second precursor. An example of the second precursor is a compound having an Si atom to which two or more hydrolyzable functional groups are bonded. The second polymer chains 12 may be polymer chains formed by the progress of a hydrolysis reaction and a polycondensation reaction of the compound. The second precursor does not need to have vinyl polymerizability.

[0037] An example of the hydrolyzable functional group is an alkoxy group having 1 to 4 carbon atoms. From the viewpoint of stably proceeding the hydrolysis reaction and the subsequent polycondensation reaction, a methoxy group or an ethoxy group may be used. The two or more hydrolyzable functional groups possessed by the second precursor may be of only one type, in other words, all the same, or of two or more types.

[0038] An organo group may be further bonded to the Si atom of the second precursor. The number of organo groups bonded to the Si atom may be 1. The second precursor to which the organo group is further bonded is subjected to hydrolysis and polycondensation to form a second polymer chain 12, which is a polyorganosiloxane chain.

[0039] Examples of the second precursor include methyltrimethoxysilane, vinyltrimethoxysilane, dimethyldimethoxysilane, vinylmethyldimethoxysilane, 3-(diphenylphosphino)propyltriethoxysilane, glycidoxypropyltriethoxysilane, mercaptopropyltriethoxysilane, diethylaminoethyltriethoxysilane, and aminopropyltriethoxysilane. Other examples of the second precursor include [3-(2-aminoethylamino)propyl]trimethoxysilane and 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane. However, the second precursor is not limited to the above examples.

[0040] The average degree of polymerization of the second polymer chains 12, expressed by the number of siloxane bonds contained in the main chain of the second polymer chains 12, is, for example, 100 to 1,000,000, and may be 1,000 to 100,000, or even 2,000 to 50,000.

[0041] The network B and the hydrogel 1 may contain two or more second polymer chains 12 with different configurations.

[0042] <1-3.Liquid> The liquid 13 that may be contained in the hydrogel 1 is typically a substance that is in a liquid state at room temperature (25°C) and atmospheric pressure. The liquid 13 may be a solution-based solvent that forms the hydrogel 1 in the manufacturing method described below. There are no limitations on the liquid 13, as long as it can swell the hydrogel 1 without dissolving or shrinking it. Examples of the liquid 13 include water, alcohols such as methanol, ethanol, and propanol, acetone, acetonitrile, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, pentane, hexane, heptane, benzene, and toluene, and mixed solvents thereof. The liquid 13 may also be water.

[0043] The liquid 13 may be hydrophilic. In this specification, unless otherwise specified, hydrophilic means that the solubility in 100 g of water at 25°C is 1 g or more, preferably 5 g or more, and more preferably 10 g or more. The hydrophilic liquid 13 may be a liquid that is miscible with water at 25°C in any proportion. Examples of the hydrophilic liquid 13 include water, hydrophilic organic solvents, and mixed solvents thereof. Examples of the hydrophilic organic solvent are alcohols, acetone, and acetonitrile. However, the hydrophilic liquid 13 and the hydrophilic organic solvent are not limited to the above examples.

[0044] The hydrogel 1 of this embodiment, which includes multiple networks with different properties, Network A and Network B, may contain a hydrophobic liquid 13. In this specification, unless otherwise specified, hydrophobic means that the solubility in 100 g of water at 25°C is less than 1 g, preferably 0.1 g or less, and more preferably 0.01 g or less. An example of the hydrophobic liquid 13 is a hydrophobic organic solvent. The hydrophobic liquid 13 may also be a mixed solvent of two or more hydrophobic organic solvents. An organogel is known as a gel that is swollen with a hydrophobic liquid. In other words, the hydrogel 1 of this embodiment can also be called an organogel if the liquid 13 contained therein is hydrophobic.

[0045] The water content of liquid 13 may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, 92% by weight or more, 94% by weight or more, 95% by weight or more, 97% by weight or more, 99% by weight or more, 99.5% by weight or more, 99.7% by weight or more, or even 99.9% by weight or more. The water content of liquid 13 may be less than 10% by weight, 8% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 2% by weight or less, 1% by weight or less, 0.5% by weight or less, or even 0.1% by weight or less. Liquid 13 may be substantially free of water. "Substantially free" means that the content is, for example, 0.05% by weight or less, more preferably 0.03% by weight or less, and even more preferably 0.01% by weight or less.

[0046] <1-4.Characteristics> In the hydrogel 1 of this embodiment, the liquid 13 may be replaceable between a hydrophilic liquid and a hydrophobic liquid. Examples of the replacement include replacing the liquid 13 contained in the hydrogel 1 containing a hydrophilic liquid 13 with a hydrophobic liquid, or replacing the liquid 13 contained in the hydrogel 1 containing a hydrophobic liquid 13 with a hydrophilic liquid. The replacement may be performed via a third liquid that is compatible with both the liquid 13 before and the liquid 13 after replacement. In this case, for example, the hydrophilic liquid 13 may be replaced with the third liquid, and then the third liquid may be replaced with the hydrophobic liquid 13. In this specification, replacement is considered possible if at least one replacement is possible.

[0047] The amount of liquid 13 that the hydrogel 1 can contain can be determined using the swelling ratio of the hydrogel 1 as an indicator. For example, the swelling ratio of water in the hydrogel 1 can be used as an indicator of the amount of water and hydrophilic liquid 13 that the hydrogel 1 can contain. The swelling ratio of water at 25°C is, for example, 5% by weight or more, and may be 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or even 90% by weight or more. The upper limit of the swelling ratio is, for example, 100% by weight or less, or may be 99% by weight or less. The swelling ratio of water can be determined by the following method. (Method for evaluating swelling ratio) First, a test specimen is prepared by preparing a slice of the hydrogel 1 to be evaluated, weighing at least 0.1 g. Multiple slices may be prepared so that the total weight is 0.1 g or more. For hydrogels 1 that do not contain water as the liquid 13, the liquid 13 is replaced in advance with a highly hydrophilic liquid, such as an alcohol such as 2-propanol. Next, the test specimen is immersed in water to swell as much as possible. Pure water is preferably used. Immersion is performed at 25°C. The immersion time varies depending on the shape and size of the test specimen, but is typically 8 hours or more. Sufficient swelling can be determined by immersing the test specimen in a liquid with a volume 10 times or more of its volume three or more times. Next, any water adhering to the surface of the immersed test specimen is wiped off, and its weight, W0 (g), is measured. Next, the water contained in the test specimen is removed by drying, and the weight, W1 (g), of the dried test specimen is measured. Heating and / or reduced pressure can be used for drying. Drying conditions vary depending on the shape and size of the test piece, but are typically room temperature to 120°C for at least 8 hours. From the measured W0 and W1, the swelling ratio can be determined using the formula: swelling ratio (%) = {(W0 - W1) / W0} x 100. Measurements of W0 and W1 are carried out at 25°C.

[0048] The swelling ratio of the hydrogel 1 with heptane can be an indicator of the amount of hydrophobic liquid 13 that the hydrogel 1 can contain. The swelling ratio of heptane at 25°C is, for example, 5% by weight or more, and may be 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or even 90% by weight or more. The upper limit of the swelling ratio is, for example, 100% by weight or less, or even 99% by weight or less. The swelling ratio of heptane can be determined in the same manner as the swelling ratio of water, except that heptane is used instead of water. For hydrogels 1 that do not contain heptane as the liquid 13, the liquid 13 contained therein is replaced in advance with a liquid that is highly compatible with heptane, such as 2-propanol.

[0049] The hydrogel 1 may have the swelling ratio in water and the swelling ratio in heptane described above in any combination within the ranges exemplified.

[0050] For Hydrogel 1, the ratio of the swelling rate in heptane to the swelling rate in water [swelling rate in heptane] / [swelling rate in water] may be 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or even 0.9 or more. The upper limit of this ratio is, for example, 10 or less, and may be 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, 2 or less, or even 1 or less.

[0051] The hydrogel 1 may not have macropores. Furthermore, the hydrogel 1 may not have macropores or mesopores. In this specification, based on the IUPAC proposal, pores with a pore diameter (pore size) of more than 50 nm are referred to as macropores, and pores with a pore size of 2 nm or more and 50 nm or less are referred to as mesopores. The pore size can be determined by a general pore distribution measurement selected based on the pore size and expected pore size, such as mercury intrusion pore distribution measurement for macropores and nitrogen gas adsorption pore distribution measurement for mesopores.

[0052] The swelling ratio of the hydrogel 1 may be a value for the hydrogel 1 that does not have macropores, or may be a value for the hydrogel 1 that does not have macropores or mesopores.

[0053] It is also possible to intentionally provide macropores and / or mesopores in the hydrogel 1. The swelling ratio of the hydrogel 1 may be a value in a region of the hydrogel 1 that does not have macropores, or may be a value in a region of the hydrogel 1 that does not have macropores or mesopores.

[0054] 1, Network A and Network B are not covalently bonded, i.e., are independent of each other. Thus, the hydrogel 1 of this embodiment does not need to have a bonding point that covalently bonds Network A and Network B. However, Network A and Network B may be partially bonded by a covalent bond.

[0055] The hydrogel 1 may have flexibility. The low crosslinking density of the hydrogel 1 may contribute to the flexibility. The flexibility of the hydrogel 1, expressed in Young's modulus, may be, for example, 100 MPa or less, and may be 75 MPa or less, 50 MPa or less, 40 MPa or less, 30 MPa or less, 20 MPa or less, 15 MPa or less, 10 MPa or less, 8 MPa or less, 6 MPa or less, 5 MPa or less, 3 MPa or less, 1 MPa or less, 0.5 MPa or less, or even 0.1 MPa or less. The lower limit of the Young's modulus may be 0.05 MPa or more, 0.1 MPa or more, 0.2 MPa or more, 0.3 MPa or more, 0.4 MPa or more, 0.5 MPa or more, 0.7 MPa or more, 0.9 MPa or more, 1 MPa or more, 1.2 MPa or more, 1.4 MPa or more, or even 1.5 MPa or more. The Young's modulus can be determined by a compression test or a tensile test.

[0056] The hydrogel may have both the swelling property and Young's modulus described above.

[0057] The shape of the hydrogel 1 of this embodiment is not limited, and the hydrogel of this embodiment can take various shapes such as particles, sheets, and bulks (lumps) such as rectangular parallelepipeds and disks.

[0058] <1-5. Other ingredients> The hydrogel 1 of this embodiment may further contain materials other than those mentioned above.

[0059] An example of a material that the hydrogel 1 of this embodiment may further contain is a metal species. In other words, the hydrogel 1 may further contain a metal species. However, the materials that may further be contained are not limited to the above examples.

[0060] The metal species may be retained within at least one network selected from the group consisting of Network A and Network B of the hydrogel 1. Alternatively, the metal species may be coordinated to at least one network selected from the group consisting of Network A and Network B of the hydrogel 1. At least one network selected from the group consisting of Network A and Network B may have a functional group and / or chemical structure capable of functioning as a ligand for the metal species in its main chain and / or side chain. The functional group and chemical structure capable of functioning as a ligand varies depending on the type of metal species. For example, when the metal species is Pt (platinum), the functional group and chemical structure capable of functioning as a ligand include a vinyl group, an ether group, a structure having an amine group such as a diamine structure or a triamine structure, and a diphenylphosphino group. The ether group may be contained in, for example, a siloxane bond or an ethylene glycol structure. However, the functional group and chemical structure capable of functioning as a ligand are not limited to the above examples.

[0061] Being able to coordinate to a molecular chain network means that the metal species can be contained in hydrogel 1 in a state smaller than nanoparticles, in other words, without agglomerating to form nanoparticles. Nanoclusters, which are smaller than nanoparticles, can be in a mononuclear state consisting of one atom or in a cluster state consisting of several to several tens of atoms. In this specification, "nanoparticles" refers to particles with an average particle diameter of 3 nm or more and less than 1 μm as evaluated by transmission electron microscopy.

[0062] Examples of the metal species are first, second or third transition series elements, or alloys thereof. The metal species may be Pd (palladium), Pt, Ag (silver), Au (gold), Rh (rhodium), Ir (iridium), Re (rhenium), Ru (ruthenium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), or Cu (copper), or alloys thereof.

[0063] The valence of the metal species contained in the hydrogel 1 may be zero or other than zero. The metal species may be in the form of metal ions. The hydrogel 1 may contain two or more of the same metal species with different valences.

[0064] The content of the metal species in the hydrogel 1 containing the metal species is, for example, 0.01 to 20% by weight, and may be 0.1 to 10% by weight, 0.5 to 5% by weight, or even 1 to 3% by weight.

[0065] Another example of a material that the hydrogel 1 of this embodiment may further contain is a stabilizer for metal species, such as polymethylhydrosiloxane (PMHS).

[0066] The materials that may be further included are not limited to the examples given above.

[0067] <1-6.Applications> In view of the possibility of containing metal species, the hydrogel 1 according to this embodiment is for carrying metal species. In other words, the hydrogel 1 may be a carrier of metal species.

[0068] The hydrogel 1 containing metal species may be used as a catalyst by focusing on the catalytic action of the metal species. From this perspective, the hydrogel 1 may be used for a catalyst or a catalyst support, or may be a catalyst support. The hydrogel 1 has the property of being swellable by a liquid 13. The ability to swell can contribute to improving the permeability of reactants to the metal species located inside the hydrogel 1, more specifically, inside the skeleton of the hydrogel 1. In other words, the hydrogel 1 is suitable for use as a catalyst or catalyst support with high reaction efficiency.

[0069] The hydrogel of this embodiment may be a hydrogel obtained by the hydrogel manufacturing method described below.

[0070] <1-7. Different embodiments> A hydrogel according to a different embodiment of the present invention (hereinafter referred to as the "second hydrogel") may be the following hydrogel: a first polymer chain network A which is a polymer chain of a precursor having vinyl polymerizability; a second polymer chain network B having a siloxane bond in the main chain; Including, The hydrogel does not have any bonding points that bond the network A and the network B together by a covalent bond.

[0071] The second hydrogel can have the same configuration and properties as those described above in the description of the first hydrogel, including preferred examples, so long as it does not have covalently bonded connection points between Network A and Network B.

[0072] The use of the second hydrogel is not limited. Since the second hydrogel may contain metal species, it may be used to support metal species. The second hydrogel may also be used as a medical material, such as a drug-releasing material used in a drug delivery system, a tissue scaffold material used in regenerative medicine, a bioimplant material, or a wound protection agent. In other words, the second hydrogel may be for medical purposes.

[0073] <<2. Dried hydrogel>> The dried hydrogel according to the embodiment of the present invention is a dried hydrogel of the first or second hydrogel described above. The dried hydrogel can be formed by drying the first or second hydrogel, in other words, by removing the liquid contained in the hydrogel. Drying can be achieved by replacing the liquid with a more volatile liquid, heating, reducing pressure, or the like.

[0074] The dried hydrogel may have the same configuration as that described above in the description of the first hydrogel or the second hydrogel, except that it is substantially free of liquid.

[0075] The dried hydrogel may be one that can be restored to the first hydrogel or the second hydrogel by impregnation with a liquid, or may be a dried hydrogel that can be reversibly restored and further dried.

[0076] The use of the dried hydrogel is not limited, and may be for supporting metal species after restoration, or for medical use, such as for use as a medical material after restoration.

[0077] <<3. Catalyst>> A catalyst according to an embodiment of the present invention includes a hydrogel 1 further comprising a metal species. The hydrogel 1 further comprising a metal species is as described above.

[0078] In the hydrogel 1 contained in the catalyst of this embodiment, the metal species may be held inside at least one selected from the group consisting of network A and network B of the hydrogel 1, or may be coordinated to at least one selected from the group consisting of network A and network B.

[0079] The catalyst of this embodiment contains the hydrogel 1, and therefore can be used as a heterogeneous catalyst. The fact that it can be used as a heterogeneous catalyst can contribute to the application of not only chemical reactions in a liquid phase but also chemical reactions in a gas phase or a gas-liquid mixed phase. Furthermore, the fact that it can be used as a heterogeneous catalyst can contribute to the recovery of metal species after a reaction.

[0080] The catalyst of this embodiment may be applied to various chemical reactions. Examples of applicable reactions include oxidation reactions, reduction reactions, addition reactions, elimination reactions, condensation reactions, and cyclization reactions. Other examples of reactions include CH activation reactions, coupling reactions, and metathesis reactions. More specific examples include hydrosilylation reactions, cross-coupling reactions, Sonogashira coupling, Hiyama coupling, Suzuki-Miyaura coupling, Mizoroki-Heck coupling, ZACA reaction, and Wacker oxidation. However, applicable reactions are not limited to the above examples. The catalyst of this embodiment may be a hydrosilylation catalyst or a Mizoroki-Heck coupling catalyst.

[0081] The type of metal species may be selected depending on the chemical reaction to which the catalyst is applied.

[0082] The valence of the metal species contained in the catalyst of this embodiment may be zero or a non-zero value. The metal species contained in the catalyst of this embodiment may be a metal ion. The catalyst of this embodiment may contain two or more of the same metal species but with different valences.

[0083] The amount of the metal species supported in the catalyst of this embodiment varies depending on the chemical reaction to be applied, but may be, for example, 0.01 to 20% by weight, 0.1 to 10% by weight, 0.2 to 8% by weight, 0.3 to 7% by weight, 0.35 to 6.5% by weight, 0.4 to 6% by weight, 0.5 to 5% by weight, or even 1 to 4% by weight. When the metal species is at least one selected from the group consisting of Pt, Pd, Ni, Co, and Fe, a catalyst with a supported amount within the above range is particularly suitable for application to hydrosilylation reactions.

[0084] The metal species in the catalyst of this embodiment may be contained in the hydrogel 1 in a state where they have a size smaller than nanoparticles, in other words, without agglomerating to form nanoparticles.

[0085] The catalyst of this embodiment can exhibit high catalytic activity, which is thought to be due to the presence of metal species in the hydrogel 1, which can swell with the liquid 13. The high catalytic activity may be due to the ability of reactants to penetrate into the interior of the hydrogel 1, in other words, the ability to increase the density of metal species that can come into contact with the reactants. For example, in conventional catalysts in which metal species, typically metal nanoparticles, are supported on the surface of a porous gel skeleton, even if metal species are present inside the skeleton, the metal species that can come into contact with the reactants are limited to those located on or near the surface of the skeleton. The catalyst of this embodiment can achieve a TOF value that is one order of magnitude higher in a hydrosilylation reaction than a Karlstedt catalyst, depending on the configuration of the hydrogel 1 and the catalyst and the reaction conditions.

[0086] In the catalyst of this embodiment, metal species are held inside the hydrogel 1. Holding the metal species inside the hydrogel 1 can contribute to suppressing desorption (leaching) of the metal species from the catalyst. For example, the catalyst of this embodiment can suppress desorption of the metal species more effectively than conventional catalysts in which metal species, typically metal nanoparticles, are supported on the surface of a porous gel skeleton.

[0087] The catalyst of this embodiment can have both the high catalytic activity and the effect of suppressing the desorption of metal species.

[0088] The shape of the catalyst of this embodiment is not limited, and can take various shapes such as particles, sheets, and bulks (lumps) such as rectangular parallelepipeds and disks.

[0089] The catalyst of this embodiment may further contain materials other than the hydrogel 1 as long as the catalyst has a catalytic effect.

[0090] The catalyst of this embodiment may be a catalyst obtained by the catalyst production method described below.

[0091] The catalyst of this embodiment may contain a second hydrogel containing a metal species instead of the hydrogel 1 (first hydrogel) containing a metal species.

[0092] <<4. Hydrogel manufacturing method>> A hydrogel (first hydrogel) according to one embodiment of the present invention can be produced, for example, by the following production method.

[0093] The method for producing the hydrogel of this embodiment includes: A solution system including a first precursor having vinyl polymerizability and a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, forming a hydrogel for supporting metal species, the hydrogel including the network A and the network B;

[0094] <4-1. First precursor and second precursor> Examples of the first precursor and the second precursor that the solution system may contain in the method for producing the hydrogel of this embodiment, including preferred examples, are the same as the examples described above in the description of the hydrogel of this embodiment.

[0095] <4-2. Polymerization of the first precursor> For example, radical polymerization can be selected for the polymerization of the first precursor. However, the polymerization method is not limited to the above examples. Radical polymerization can be carried out by any polymerization method such as solution polymerization, emulsion polymerization, suspension polymerization, etc. Solution polymerization is particularly suitable for efficiently proceeding with the polymerization of the first precursor along with the hydrolysis reaction and polycondensation reaction of the second precursor.

[0096] The solution system may contain a substance for promoting polymerization of the first precursor. An example of such a substance is a polymerization initiator. Various initiators such as azo-based, peroxide-based, and redox-based initiators can be selected as the polymerization initiator. Examples of the azo polymerization initiator include 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis[N-(2-propenyl)2-methylpropionamide], 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide). Examples of peroxide-based polymerization initiators include t-butyl peroxybenzoate and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, but the polymerization initiator is not limited to these examples.

[0097] The amount of the polymerization initiator added to the solution system is, for example, 0.01 to 10 parts by weight, and may be 0.1 to 1 part by weight, relative to 100 parts by weight of the first precursor.

[0098] The polymerization of the first precursor may be carried out under temperature conditions of, for example, 20 to 120° C., or further, 30 to 80° C. The polymerization time is, for example, 0.5 to 20 hours.

[0099] Photoradical polymerization may be selected as the polymerization of the first precursor. When photoradical polymerization is selected, the solution system may contain a photopolymerization initiator. Examples of photopolymerization initiators include acetophenone-based compounds such as diethoxyacetophenone; benzoin-based compounds such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acylphosphine oxide-based compounds such as 2,4,6-trimethylbenzoin diphenylphosphine oxide; benzophenone-based compounds such as benzophenone and hydroxybenzophenone; thioxanthone-based compounds such as 2-isopropylthioxanthone and 2,4-dimethylthioxanthone; aminobenzophenone-based compounds such as 4,4'-diethylaminobenzophenone; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, and camphorquinone. However, the photopolymerization initiator is not limited to the above examples.

[0100] The amount of the photopolymerization initiator added to the solution system is, for example, 0.01 to 10 parts by weight, and may be 0.1 to 1 part by weight, relative to 100 parts by weight of the first precursor.

[0101] When photoradical polymerization is selected, a photopolymerization accelerator may be combined with the photopolymerization initiator. Examples of photopolymerization accelerators include benzoic acid compounds such as 4-dimethylaminobenzoic acid, ethyl 4-dimethylaminobenzoate, n-butoxyethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and 2-ethylhexyl 4-dimethylaminobenzoate; and tertiary amine compounds such as triethanolamine, methyldiethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone, and 4,4'-diethylaminobenzophenone. However, the photopolymerization accelerator is not limited to the above examples.

[0102] When a photopolymerization accelerator is used in combination, the amount of the photopolymerization accelerator added to the solution system is, for example, 0.01 to 10 parts by weight, or may be 0.1 to 1 part by weight, relative to 100 parts by weight of the first precursor.

[0103] The photoradical polymerization of the first precursor may be carried out at a temperature of, for example, 0 to 50° C. The polymerization time is, for example, 0.02 to 60 minutes. The light source can be selected from those capable of irradiating light having a peak wavelength in the wavelength range of 380 to 780 nm, preferably 430 to 485 nm.

[0104] <4-3. Hydrolysis reaction and polycondensation reaction of the second precursor> The hydrolysis and polycondensation reactions of the second precursor are typically carried out by a sol-gel process, which is particularly suitable for carrying out the hydrolysis and polycondensation reactions of the second precursor simultaneously with the polymerization of the first precursor.

[0105] The solution system may contain a substance for promoting the hydrolysis reaction and polycondensation reaction of the second precursor. Examples of such substances include an acid catalyst or a basic catalyst. Both an acid catalyst and a basic catalyst may be selected. In this case, the acid catalyst may be added to the solution system to promote the hydrolysis reaction, and then the basic catalyst may be added to the solution system to promote the polycondensation reaction. The acid catalyst and the basic catalyst release hydrogen ions and hydroxide ions, respectively, to change the pH of the solution system and promote the hydrolysis reaction and polycondensation reaction of the second precursor.

[0106] Examples of acid catalysts are hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, perchloric acid, acetic acid, citric acid, trifluoroacetic acid, and trifluoromethanesulfonic acid. Examples of basic catalysts are sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, ammonium hydroxide, pyridine, triethylamine, alkylammonium hydroxide, and urea. The basic catalyst may be a quaternary ammonium hydroxide. Examples of quaternary ammonium hydroxides are tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide, and tetrapropylammonium hydroxide. The basic catalyst may be TMAOH.

[0107] The total amount of the acid catalyst and basic catalyst added to the solution system is, for example, 0.1 to 30 parts by weight, 0.5 to 20 parts by weight, or even 1 to 10 parts by weight, per 100 parts by weight of the second precursor.

[0108] The hydrolysis reaction and polycondensation reaction in the sol-gel method can proceed continuously. The reaction temperature is, for example, 0 to 120° C., and may be 20 to 100° C., or even 30 to 80° C. The reaction time is, for example, 1 to 120 hours, and may be 1 to 72 hours.

[0109] It is preferable that the polymerization of the first precursor and the hydrolysis reaction and polycondensation reaction of the second precursor proceed simultaneously. To allow the reactions to proceed simultaneously, the temperature and polymerization (reaction) time can be adjusted. The temperature of the solution system suitable for simultaneous proceeding is, for example, 20 to 120°C, or may be 30 to 80°C. The polymerization (reaction) time suitable for simultaneous proceeding is, for example, 1 minute to 72 hours, or may be 1 hour to 24 hours.

[0110] <4-4. Solvent> The solution solvent may be the same as the liquid 13 contained in the hydrogel to be finally obtained. A solvent different from the liquid 13 may also be selected, in which case the solution solvent contained in the formed hydrogel may be replaced with the liquid 13. In this respect, the method for producing a hydrogel of this embodiment may further include replacing the solution solvent contained in the formed hydrogel with the liquid 13. The replacement may be performed via a third solvent that is miscible with both the solution solvent and the liquid 13. Examples of the solution solvent are the same as the examples of the liquid 13 described above in the description of the hydrogel 1. The solution solvent may be hydrophilic. In this case, the method for producing a hydrogel may further include replacing the hydrophilic solvent contained in the formed hydrogel with the hydrophobic liquid 13. The replacement may be performed via a third solvent that is miscible with both the hydrophilic solvent and the liquid 13.

[0111] <4-5. Other substances> The solution system may contain other substances as long as they are capable of forming the hydrogel of this embodiment. One example of such other substances is a phase separation inhibitor. For example, a substance that has affinity for both the solvent of the solution system and the polymer chains of the first precursor and the second precursor can be selected as the phase separation inhibitor. Examples of phase separation inhibitors include nonionic surfactants, cationic surfactants, quaternary ammonium halide salts having two or more carbon atoms, and block copolymers. The phase separation inhibitor may be at least one selected from the group consisting of n-hexadecyltrimethyl chloride, n-hexadecyltrimethyl bromide, sodium n-hexadecylate, polyethylene oxide-block-polypropylene oxide-block-polyethylene oxide, and polyoxyethylene alkyl ethers having two or more carbon atoms.

[0112] Another example of the other substance is a metal species. In the method for producing a hydrogel of this embodiment, a hydrogel further containing a metal species may be formed from a solution system containing the metal species. A hydrogel may be formed that further contains a metal species held inside at least one selected from the group consisting of Network A and Network B, or a hydrogel may be formed that further contains a metal species coordinated to at least one selected from the group consisting of Network A and Network B.

[0113] Examples of metal species that the solution system may contain are the same as those described above in the description of hydrogel 1. The metal species may be contained in the solution system as a metal salt. Examples of metal salts include oxides, hydroxides, fluorides, chlorides, bromides, iodides, carbonates, phosphates, sulfates, nitrates, perchlorates, acetates, acetylacetonates, tetrafluoroborane salts, hexafluorophosphine salts, cyclopentadiene salts, trifluoromethanesulfonates, triphenylphosphine salts, and amine salts of the above-mentioned metal species. The metal salt may be a double salt with an alkali metal such as sodium or potassium. The metal species may be contained in a phase separation inhibitor.

[0114] Depending on the structure of the hydrogel and the type of metal species, a hydrogel containing a metal species can also be formed by immersing the hydrogel formed by the above method in a solution containing the metal species. The metal species contained in the solution may be a metal salt. Examples of metal salts are as described above.

[0115] After forming a hydrogel containing a metal salt, the metal species contained in the formed hydrogel may be reduced. In this respect, the manufacturing method of this embodiment may further include reducing the metal species contained in the formed hydrogel. The reduction may reduce the valence of the metal species contained in the hydrogel to zero. The reduction of the metal species may contribute to improving catalytic activity, depending on, for example, the type and reaction conditions of the applied chemical reaction.

[0116] The reduction of the metal species can be carried out, for example, by immersing the hydrogel in a solution containing a reducing agent. Alternatively, the metal species can be reduced by adding a reducing agent to the solution system in which the hydrogel is formed. Alternatively, the formed hydrogel can be removed from the solution system and then immersed in another solution containing a reducing agent to reduce the metal species.

[0117] Examples of reducing agents include hydrosilane compounds such as triethylsilane and polymethylhydrosiloxane (PMHS), hydrazine, sodium borohydride, lithium aluminum hydride, diisobutylaluminum hydride, sodium cyanoborohydride, potassium graphite, oxalic acid, formic acid, 3,4,5-trihydroxybenzoic acid, methanol, ethanol, propanol, butanol, sugars, iron (II) compounds, tin (II) compounds, sulfite compounds, borane compounds such as borane-tetrahydrofuran complex, and hydrogen. However, the reducing agent is not limited to the above examples. The amount of reducing agent to be added varies depending on the type and amount of metal species contained in the hydrogel, but may be, for example, 0.001 to 100 parts by weight, 0.01 to 10 parts by weight, or even 0.1 to 1 part by weight per 100 parts by weight of the hydrogel.

[0118] Another example of other substances that the solution system may contain is a stabilizer for the metal species.

[0119] The method for producing a hydrogel according to the present embodiment may include any step other than those described above, as long as the method can produce the hydrogel described above. An example of such a step is a washing step for removing unreacted components remaining in the formed hydrogel. A solution capable of swelling the hydrogel can be used in the washing step.

[0120] <4-6. Second hydrogel manufacturing method> The second hydrogel can be produced, for example, by the following production method.

[0121] The second method for producing a hydrogel comprises: A solution system including a first precursor having vinyl polymerizability and a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, The method may include forming a hydrogel that includes the network A and the network B, but does not have any covalent bonding points between the network A and the network B.

[0122] The method for producing the second hydrogel can be carried out in the same manner as the method for producing the first hydrogel, so long as it forms a hydrogel that does not have a bonding point that covalently bonds Network A and Network B. To form the hydrogel that does not have a bonding point, for example, the type of the first precursor and / or the second precursor may be selected.

[0123] <<5. Catalyst manufacturing method>> The catalyst according to the embodiment of the present invention can be produced, for example, by the following production method.

[0124] The method for producing a catalyst of this embodiment includes: 1. A method for producing a catalyst comprising a hydrogel containing a metal species, comprising: A solution system including a first precursor having vinyl polymerizability, a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, and a metal species, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, forming a hydrogel comprising the network A and the network B, and the metal species.

[0125] A more specific example of the method for forming a hydrogel containing metal species in the method for producing a catalyst according to this embodiment is the same as the example described above in the description of the first method for producing a hydrogel.

[0126] The method for producing a catalyst according to this embodiment may include forming a hydrogel containing a metal species by the first method for producing a hydrogel or the second method for producing a hydrogel described above.

[0127] The method for producing the catalyst according to this embodiment may include any steps other than those described above, as long as the catalyst according to this embodiment can be formed. [Example]

[0128] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0129] [Group 1: Examples that do not contain metal species] Example 1 3 mL of hydroxyethyl methacrylate (HEMA, manufactured by Tokyo Chemical Industry Co., Ltd.) as the first precursor and 38 mg of 4,4'-azobis(4-cyanovaleric acid) as the polymerization initiator were added to 3.3 mL of aqueous acetic acid solution containing acetic acid as an acid catalyst at a concentration of 5 mmol / L and stirred to homogenize. Next, 1.0 mL of methyltrimethoxysilane (MTMS) as the second precursor was added and stirred for 10 minutes to promote the hydrolysis reaction of MTMS. Next, 3 g of poly(oxyethylene) 2-ethylhexyl ether (Nonion EH-208, manufactured by NOF Corporation) as a nonionic surfactant and 0.2 mL of tetramethylammonium hydroxide (TMAOH) at a concentration of 0.5 mol / L as a basic catalyst were added and stirred to homogenize. The mixture was then heated to 60°C to gel the entire mixture, and then left to stand at 60°C for 24 hours for aging. Next, the aged gel was immersed in 100 mL of 2-propanol and left to stand at 60°C for 8 hours (solvent exchange) three times to remove unreacted components remaining inside the gel. In this way, the hydrogel of Example 1 was obtained.

[0130] The hydrogel of Example 1 contained a first polymer chain network A, which was HEMA polymer chains, a second polymer chain network B, which was MTMS polymer chains, and 2-propanol as a liquid. The hydrogel of Example 1 was always in a swollen state, including when immersed in 2-propanol. Visual inspection of the hydrogel of Example 1 revealed that it was translucent. Furthermore, given its composition, it was difficult for the hydrogel of Example 1 to have covalent bonding points between Network A and Network B, and observation with an electron microscope after drying revealed that it had no macropores.

[0131] <Examples 2 to 24, Comparative Examples 1 to 14> Hydrogels of Examples 2 to 24 and Comparative Examples 1 to 14 were prepared in the same manner as in Example 1, except that the types and amounts of the first and second precursors were changed as shown in Tables 1A and 1B below. The second precursor was not used in the formation of Comparative Examples 1 to 14. Furthermore, for Comparative Examples 4 to 8, although gels were initially formed, they were all dissolved by solvent exchange, and ultimately no hydrogels were obtained. In the "Type" column of each of the following tables, including Tables 1A and 1B, a " / " indicates that the precursor listed to the left of the " / " and the precursor listed to the right were used in combination. Furthermore, the left and right sides of the " / " in the "Amount Used" column indicate the amount of precursor used that is listed to the left of the " / " and the amount of precursor used that is listed to the right of the " / " in the "Type" column, respectively.

[0132] [Table 1A]

[0133] [Table 1B]

[0134] The abbreviations in Tables 1A and 1B are as follows: (First precursor) HEMA: 2-hydroxyethyl methacrylate PEGMA360: Poly(ethylene glycol) methacrylate / average molecular weight 360 acacMA: (2-acetoacetoxy)ethyl methacrylate BzMA: benzyl methacrylate IPMA: Isopropyl methacrylate DEAEMA: 2-(diethylamino)ethyl methacrylate AA: acrylic acid VyMA: vinyl methacrylate (EO)2MA: Ethylene oxide methacrylate (Second precursor) MTMS: Methyltrimethoxysilane VTMS: vinyltrimethoxysilane PTMS: Phenyltrimethoxysilane DMDMS: dimethoxydimethylsilane TMOS: Tetramethoxysilane

[0135] <Evaluation> The following evaluations were carried out for each of the hydrogels of Examples 1 to 24 and Comparative Examples 1 to 3 and 9 to 14. For Comparative Examples 4 to 8, no hydrogel was obtained, so evaluation could not be carried out.

[0136] Young's Modulus The hydrogel was cut into a rectangular column (8 mm × 8 mm square base, 20 mm high) to form a test specimen, which was then placed in a mold (rectangular column, 8 mm × 8 mm internal dimensions, 40 mm high). The measuring part (circular, 2.0 mm diameter) of a spring-loaded scale hardness tester (Oba Keiki Seisakusho, 0-300 g) was then pressed against the top surface of the test specimen, and the stress value was read when the pressed part sank 2 mm, i.e., when the compressive strain reached 10%. The Young's modulus was calculated from the read stress value and the cross-sectional area of ​​the measuring part, and this was determined as the Young's modulus of the hydrogel. The upper limit of the hardness tester was 6.2 MPa.

[0137] [Swelling rate] (Water swelling rate, heptane swelling rate, swelling rate balance) The swelling ratios in water and heptane were evaluated using the method described above. The test specimen weighed 0.1 g. If necessary, the specimen was immersed in water or heptane for three 8-hour periods. Pure water was used. The weight of the test specimen after drying, W1, was the weight of the specimen dried at 60°C for 24 hours. The ratio [heptane swelling ratio] / [water swelling ratio] was calculated to determine the hydrophobic / hydrophilic balance of the swelling ratio.

[0138] The evaluation results are shown in Tables 2A and 2B below.

[0139] [Table 2A]

[0140] [Table 2B]

[0141] As shown in Tables 2A and 2B, the hydrogels of the Examples were improved in at least one property selected from Young's modulus, swelling ratio in water, and swelling ratio in heptane, compared to the hydrogels of the Comparative Examples.

[0142] [Group 2: Examples including metal species] Example 31: Example of supporting metal species by post-addition Hydrogels were prepared in the same manner as in Example 1, except that the types and amounts of the first precursor and second precursor were changed as shown in Table 3 below.

[0143] [Table 3]

[0144] 0.2 g of the prepared hydrogel was immersed in 1.6 mL of a 4 mmol / L aqueous solution of potassium platinum chloride (K2PtCl4) and allowed to stand at 40°C for 3 days. The hydrogel was then washed by immersing it in 2-propanol and leaving it overnight at 40°C three times to remove the reaction by-product KCl. The washed hydrogel was then immersed in 20 mL of 2-propanol containing 0.1 mL of polymethylhydrosiloxane (PMHS; average molecular weight 1400-1800) as a reducing agent and allowed to stand at 40°C for 3 hours to reduce the Pt inside the gel. After confirming that hydrogen generation by reduction had ceased, the hydrogel was immersed in 100 mL of 2-propanol at 25°C for washing, thereby removing unreacted PMHS. This yielded the hydrogel of Example 31, which contained Pt as the metal species and 2-propanol as the liquid. The hydrogel of Example 31 remained swollen at all times, including when immersed in a K2PtCl4 aqueous solution, 2-propanol, and a 2-propanol solution containing PMHS. Furthermore, the hydrogel of Example 31 was visually translucent, and the brown color due to visible light absorption caused by plasmon resonance, which is characteristic of Pt nanoparticles, was not observed. This confirmed that Pt was retained within the gel at sizes smaller than nanoparticles. Pt was estimated to be coordinated in Network A and Network B in the form of mononuclei or small clusters. Possible coordination states are shown in Figure 2. The Pt loading, calculated from the weight ratio of the materials used, was 1 wt% of the hydrogel weight.

[0145] <Examples 32 to 35: Examples of supporting metal species by post-addition> The hydrogels of Examples 32 to 35 were obtained in the same manner as in Example 31, except that the concentration of the K2PtCl4 aqueous solution was changed as shown in Table 4 below. All of the hydrogels of Examples 32 to 35 remained swollen at all times, including when immersed in a K2PtCl4 aqueous solution, 2-propanol, and a 2-propanol solution containing PMHS. Furthermore, the hydrogels of Examples 32 to 35 were translucent when visually inspected. The hydrogels of Examples 32 and 33 were brown in color, indicating that Pt grown as nanoparticles was retained within the gel. The hydrogels of Examples 34 and 35 were white in color, confirming that Pt was retained within the gel at a size smaller than nanoparticles. The Pt loadings calculated from the weight ratios of the materials used were 10 wt% (Example 32), 5 wt% (Example 33), 2 wt% (Example 34), and 0.5 wt% (Example 35) of the hydrogel weight.

[0146] [Table 4]

[0147] <Examples 36 and 37: Examples of supporting metal species by blending into a solution system> A hydrogel was obtained in the same manner as in Example 31, except that an aqueous acetic acid solution containing 454 mg of K2PtCl (the acetic acid concentration was the same at 5 mmol / L) was used instead of the 5 mmol / L aqueous acetic acid solution. The obtained hydrogel contained a first polymer chain network A, which was a PEGMA polymer chain, a second polymer chain network B, which was a VTMS polymer chain, and 2-propanol as a liquid. The obtained hydrogel remained in a swollen state at all times, including when immersed in 2-propanol. The obtained hydrogel was translucent when visually inspected.

[0148] Next, the resulting hydrogel was immersed in 20 mL of a 2-propanol solution containing 0.5 mL of PMHS (average molecular weight 1400-1800) as a reducing agent and allowed to stand at 40 °C for 3 hours to reduce the Pt inside the gel. After confirming that hydrogen generation by reduction had ceased, the hydrogel was immersed in 100 mL of 2-propanol at 25 °C and then in 100 mL of acetone at 25 °C for washing, yielding hydrogels of Examples 36 and 37, which contained Pt as the metal species and contained acetone as the liquid. Note that the hydrogels of Examples 36 and 37 were identical in gel form; only the reaction time in the catalytic activity test described below differed. The hydrogels of Examples 36 and 37 remained swollen throughout the entire process, including immersion in a 2-propanol solution containing PMHS, immersion in 2-propanol, and immersion in acetone. The hydrogels of Examples 36 and 37 were visually transparent, and it was confirmed that Pt particles smaller than nanoparticles were retained inside the gel. The amount of Pt supported, calculated from the weight ratio of the materials used, was 1 wt% of the weight of the hydrogel.

[0149] Example 38 The hydrogel of Example 38, in which Pt was supported, was obtained in the same manner as in Examples 36 and 37, except that PEGMA (PEGMA500) with an average molecular weight of 500 was used as the first precursor and reduction with a reducing agent was not performed.

[0150] Example 39 The hydrogel of Example 39 carrying Pt was obtained in the same manner as in Examples 36 and 37, except that PEGMA having an average molecular weight of 500 was used as the first precursor.

[0151] <Example 40> The hydrogel of Example 40, in which Pt was supported, was obtained in the same manner as in Examples 36 and 37, except that PEGMA with an average molecular weight of 500 was used as the first precursor, a mixture of VTMS and methyltrimethoxysilane (MTMS) (volume ratio 1:1) was used as the second precursor, and reduction with a reducing agent was not performed.

[0152] <Example 41> The hydrogel of Example 41, carrying Pt, was obtained in the same manner as in Examples 36 and 37, except that PEGMA with an average molecular weight of 500 was used as the first precursor and a mixture of VTMS and methyltrimethoxysilane (MTMS) (volume ratio 1:1) was used as the second precursor.

[0153] The hydrogels of Examples 38 to 41 all contained a first polymer chain network A, which was PEGMA polymer chains, a second polymer chain network B, which was VTMS polymer chains, and acetone as a liquid. Each hydrogel was always in a swollen state, including when immersed in a 2-propanol solution containing PMHS, 2-propanol, and acetone.

[0154] Furthermore, visual inspection of each hydrogel confirmed that it was white and that Pt was retained within the gel at sizes smaller than nanoparticles. Pt was estimated to be coordinated in Network A and Network B in the form of mononuclear or small clusters. The amount of Pt supported, calculated from the weight ratio of the materials used, was 1 wt% of the weight of each hydrogel.

[0155] <Examples 42 to 54> The hydrogels of Examples 42 to 54 were obtained in the same manner as in Examples 36 and 37, except that the substances shown in Table 5 below were used as the first precursor and second precursor.

[0156] [Table 5]

[0157] The abbreviations in Table 5 are as follows: (First precursor) BzMA: benzyl methacrylate IPMA: Isopropyl methacrylate VyMA: vinyl methacrylate HEMA: 2-hydroxyethyl methacrylate AA: acrylic acid DVB: Divinylbenzene PEGMA360: Poly(ethylene glycol) methacrylate / average molecular weight 360 IPN: Isoprene (Second precursor) VTMS: vinyltrimethoxysilane MTMS: Methyltrimethoxysilane TMOS: Tetramethoxysilane PTMS: Phenyltrimethoxysilane

[0158] The hydrogels of Examples 42 to 54 all contained a first polymer chain network A, which was polymer chains of a first precursor, a second polymer chain network B, which was polymer chains of a second precursor, and acetone as a liquid. Each hydrogel was always in a swollen state, including when immersed in a 2-propanol solution containing PMHS, 2-propanol, and acetone.

[0159] Furthermore, each hydrogel was visually confirmed to be transparent, and it was confirmed that Pt was retained inside the gel at sizes smaller than nanoparticles. Pt was estimated to be coordinated in Network A and Network B in the form of mononuclear or small clusters. The amount of Pt loaded, calculated from the weight ratio of the materials used, was 1 wt% of the weight of each hydrogel.

[0160] <Evaluation> The hydrogels of Examples 31 to 54 were evaluated as follows.

[0161] [Catalytic activity test - hydrosilylation reaction] An arbitrary amount of hydrogel ranging from 0.003 to 0.03 g was weighed into a glass bottle, and 0.8 mL (2.5 mmol) of deoxygenated 1-octene and 0.65 mL (3.0 mmol) of 1,1,1,3,5,5,5-heptamethyltrisiloxane were added under an argon atmosphere. The glass bottle was heated to 50°C in a dry block bath and held for 1, 6, or 15 minutes, after which the solution components in the glass bottle were recovered. The recovered solution components were analyzed by high-performance liquid chromatography (HPLC) and hydrogen nuclear magnetic resonance analysis (HNMR). 1 The progress of the reaction was analyzed by 1 H-NMR.

[0162] The HPLC analysis was carried out under the following measurement conditions. Mobile phase: Acetonitrile and water mixture (volume ratio 95:5) Mobile phase flow rate: 1.6 mL / min Column: GL Sciences Inertsil ODS-3 (φ3 × 100 mm) Column oven: 40℃ Sample injection volume: 1 μL Detector: RI (differential refractive index) detector and ultraviolet-visible photodiode array detector

[0163] 1 The H-NMR analysis was carried out under the following measurement conditions. Reference substance: deuterated chloroform Parameters used in the analysis: Proton intensity at the α-position of 1-octene (δ4.0-5.0 ppm, dd) Decrease in the integral value of Si-H (δ4.63 ppm, s) for 1,1,1,3,5,5,5-heptamethyltrisiloxane Increase in the integral value of the α-position proton intensity (δ0.64 ppm, m) of the main product of the reaction

[0164] The following parameters were evaluated in the above analysis: Ptmol% Pt mol% is a value calculated by the formula: (number of moles of Pt in the hydrogel catalyst / number of moles of 1-octene before the start of the reaction) × 100 (%), and indicates the ratio of the number of atoms in the catalyst to the number of atoms in the substrate used in the reaction. Conversion rate The conversion rate is a value calculated by the formula: {[(number of moles of 1-octene before the start of the reaction) - (number of moles of 1-octene remaining after the reaction)] / number of moles of 1-octene before the start of the reaction} x 100 (%), and indicates the ratio of the converted substrate to the substrate used in the reaction. Selectivity The selectivity is a value calculated by the formula: [number of moles of main product / (number of moles of main product+number of moles of by-products)]×100 (%), and indicates the ratio of the main product to all products produced by the reaction. Turnover number (TON) TON is a value calculated by the formula: (number of moles of 1-octene before the reaction starts) / (number of moles of Pt in the hydrogel catalyst) × conversion rate, and indicates the ratio of the substrate reacted per mole of Pt species. Turnover rate (TOF) TOF is a value calculated by the formula: TON×selectivity / reaction time, and indicates the ratio of the main reaction product obtained per mole of Pt species and per unit time.

[0165] [Method for measuring dissolved metals] A portion of the solution components recovered from the catalytic activity test was placed in a glass container, and the solvent was removed by heating at 120°C under reduced pressure. 0.5 mL of aqua regia was added to the container, and the residue was dissolved by heating at 80°C for 30 minutes. The dissolved solution was diluted with purified water to a volume of 10 mL, and the amount of Pt eluted from the hydrogel during the hydrosilylation reaction was evaluated by inductively coupled plasma (ICP) emission spectroscopy of the resulting diluted solution.

[0166] [Repeated activity test] 0.024 g of the hydrogels from Examples 36 and 37 were weighed into a glass bottle, and 0.8 mL (2.5 mmol) of 1-octene and 0.65 mL (3.0 mmol) of 1,1,1,3,5,5,5-heptamethyltrisiloxane, both of which had been deoxygenated under an argon atmosphere, were added. The glass bottle was then heated to 50°C in a dry block bath and held for 15 minutes, after which the solution components in the glass bottle were recovered. The process of adding 1-octene and 1,1,1,3,5,5,5-heptamethyltrisiloxane, heating and holding the glass bottle, and recovering the solution components was repeated two more times. The solution components recovered in each of the three times, including the first, were analyzed by HPLC and HPLC. 1 The progress of the reaction was analyzed by 1 H-NMR.

[0167] The evaluation results are shown in Tables 6 and 7 (repeated activity test) below.

[0168] [Table 6]

[0169] [Table 7]

[0170] As explained above and shown in Table 6, each of the hydrogels in Examples 31 to 54 remained swollen without shrinking during the Pt loading process using an aqueous solution, the washing process using hydrophilic organic solvents 2-propanol and acetone, and the chemical reaction process with hydrophobic organic solvents 1-octene and 1,1,1,3,5,5,5-heptamethyltrisiloxane. Furthermore, each hydrogel can be used as a heterogeneous catalyst and exhibited good catalytic activity. More specifically, (1) the hydrosilylation reaction proceeded despite the low Pt content (approximately 0.001 to 0.01 mol%) and the low temperature of 50°C, (2) the selectivity was 99% or higher in all cases, and (3) the TON value was 10 3 ~10 5 The level and TOF value are 10 4 ~10 6 / hour, which was very good. For hydrosilylation reactions, several homogeneous catalysts that are said to have excellent catalytic activity have been known. The TOF value of Pt-based homogeneous catalysts that have been reported to have excellent catalytic activity is 10 times that of the Karstedt catalyst. 4 ~10 5 / hr, 10 of N-heterocyclic carbene-platinum complexes 3 / hr, 10 of styrene-platinum complex 4 ~10 5 / hour. It was confirmed that the hydrogels of the examples can exhibit TOF values ​​equivalent to or higher than these catalysts. It was also confirmed that, despite being heterogeneous catalysts, they can exhibit catalytic activity superior to that of homogeneous catalysts. Furthermore, in all examples, the amount of eluted Pt was at the lower limit of detection, confirming that Pt desorption was extremely suppressed.

[0171] Furthermore, as shown in Table 7, the hydrogels of the examples maintained their catalytic performance even after repeated use.

[0172] The TOF values ​​of Pt-based homogeneous catalysts are reported in the following documents: ·Marko, IE et al. Selective and efficient platinum(0)-carbene complexes as hydrosilylation catalysts. Science 298, 204-206 (2002) ·Troadec, T. et al. Silacyclopropylideneplatinum(0) complex as a robust and efficient hydrosilylation catalyst. Inorg. Chem. 55, 8234-8240 (2016) ·Buisine, O. et al. Second generation N-heterocyclic carbene-Pt(0) complexes as efficient catalysts for the hydrosilylation of alkenes. Chem. Commun. 0, 3856-3858 (2005) ·Iimura, T., Akasaka, N., Kosai, T. & Iwamoto, T. A Pt(0) complex with cyclic (alkyl)(amino)silylene and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane ligands: synthesis, molecular structure, and catalytic hydrosilylation activity. Dalton Trans. 46, 8868-8874 (2017)

[0173] A reference example in which a conventional catalyst is used in a hydrosilylation reaction is shown below.

[0174] <Reference Example 1: Example using Karstedt catalyst> 1.2 mg of a xylene solution of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (Pt concentration 2 wt%, Sigma-Aldrich) was weighed into a glass bottle, and 0.8 mL (2.5 mmol) of 1-octene and 0.65 mL (3.0 mmol) of 1,1,1,3,5,5,5-heptamethyltrisiloxane, which had been deoxygenated under an argon atmosphere, were added. The addition of 1-octene and 1,1,1,3,5,5,5-heptamethyltrisiloxane spontaneously generated heat due to the reaction between the two, but this ceased within approximately 10 minutes as the reaction finished. After the reaction, the solution components in the glass bottle were collected and passed through a mercapto group-supported silica gel column (φ5.5 × 10 mm) to adsorb and remove the reacted Pt complex. Then, the solution was analyzed by HPLC and HPLC. 1 The progress of the reaction was analyzed by H-NMR. The analytical methods and items were as described above.

[0175] When the Karlstedt catalyst was used, the Pt mol% was 0.005%, the conversion rate was 94%, and the TOF value was 1.9 × 10 4 / hour. Furthermore, an attempt was made to recover the Pt complex adsorbed and removed by the silica gel column from the solution components eluted by reacting the adsorbed silica gel with hot aqua regia. However, the amount of recovered Pt obtained by evaluating the solution components using the above-mentioned measurement method was 2.0 μg, and it was confirmed that it would be difficult to recover the entire amount of Pt (24 μg) added as a homogeneous system. Even if recovery to the silica gel column were possible, it was thought that the recovery operation of Pt bound to mercapto groups in the column would require many steps, including treatment with hot aqua regia.

[0176] <Reference Example 2: Example using Pt-loaded activated carbon> The catalytic activity in the hydrosilylation reaction was evaluated by the same method as above, except that a Pt-loaded activated carbon catalyst (Sigma-Aldrich, Pt loading 5 wt%) was used instead of the hydrogel. The reaction conditions were 50°C and 6 minutes. After the reaction, the solution components in the glass bottle were collected through a PTFE membrane filter (0.22 μm). The conversion rate was 2%, and the TOF value was 1.5 × 10 4 / hour. In addition, the amount of eluted Pt obtained by evaluating a portion of the solution components using the above-mentioned measurement method was 0.0 μg. Although no elution of Pt was confirmed, the conversion rate was low at a single digit, and the activity value was one digit lower than the TOF values ​​of the hydrogels of Examples 31 to 54.

[0177] <Reference Example 3: Example using Pt-supported vinylated-aminated silica gel> 0.2 g of silica gel particles C-300 (Fujifilm Wako Pure Chemical Industries, Ltd., particle size 38-63 μm, pore size 6 nm) was dried overnight at 100°C and then immersed in 2 mL of dry toluene. Then, 0.1 mL of trimethoxyvinylsilane and 0.1 mL of aminopropyltrimethoxysilane were added and heated at 100°C for 8 hours. The reaction mixture was washed with 2-propanol to remove unreacted material, and 0.5 mL of a potassium platinum chloride-water-2-propanol solution (Pt concentration 70 mmol / mL, solvent volume ratio 50:50) was added and reacted overnight at 60°C. The resulting gel was washed with 2-propanol and then with acetone to prepare Pt-loaded silica gel particles. The Pt loading was 2.2 wt%.

[0178] The catalytic activity in the hydrosilylation reaction was evaluated by the same method as above, except that the Pt-loaded silica gel particles prepared above were used instead of the hydrogel. The reaction conditions were 60°C and 6 minutes. The conversion rate was 100%, but the TOF value was 4.8 × 10 3 The amount of Pt eluted was 2.8 μg.

[0179] <Reference Example 4: Example using Pt-supported vinylated-phosphine-modified silica gel> A porous silica gel monolith (through pore diameter 5 μm, fine pore diameter 7 nm, BET specific surface area 556 m) was prepared with reference to the description in K. Nakanishi, Y. Yamasaki, H. Kaji and N. Soga, JSST, 1994, 2, 227-231. 2A Pt-loaded silica gel monolith (0.2 g) was prepared. After drying 0.2 g of the prepared silica gel monolith overnight at 100°C, it was impregnated with 2 mL of dry toluene, and then 20 μL each of trimethoxyvinylsilane and diphenylphosphinopropyltriethoxysilane was added and heated at 100°C for 8 hours. The reactant was washed with 2-propanol to remove unreacted materials, and 80 mg of a potassium platinum chloride-water-2-propanol solution (Pt concentration 3.7 mmol / L, solvent volume ratio 50:50) was added and impregnated, followed by a reaction at 60°C overnight. The gel after the reaction was washed with 2-propanol and then with acetone to obtain a Pt-loaded silica gel monolith. Vinyl and phosphine groups were introduced as ligands into this monolith. The Pt loading was 0.19 wt%.

[0180] The catalytic activity in the hydrosilylation reaction was evaluated by the same method as above, except that the Pt-supported monolith prepared above was used instead of the hydrogel. The reaction conditions were 60°C and 6 minutes. The conversion rate was 47%, and the TOF value was 4.8 × 10 3 / hour. The amount of Pt eluted was 0.2 μg. In Reference Example 4, although elution of Pt was suppressed, the conversion rate and TOF value were low.

[0181] A comparative example will be shown below.

[0182] Comparative Example 21: Example using organic-inorganic hybrid Pt-supported gel prepared from an organic silane compound and an inorganic silane compound To 3.5 mL of an aqueous acetic acid solution (acetic acid concentration: 5 mmol / L) containing potassium platinum chloride at a concentration of 7.3 mmol / L, 1.5 mL of vinyltrimethoxysilane and 0.8 mL of vinylmethyldimethoxysilane were added and stirred for 10 minutes until a homogeneous solution was obtained. Next, 1.5 mL of poly(oxyethylene) 2-ethylhexyl ether (Nonion EH-208, NOF Corporation) and 0.2 mL of aminopropylmethyldimethoxysilane were added and stirred to obtain a homogeneous solution. The container was then sealed and heated to 60°C to promote gelation. The resulting gel was then immersed in 100 mL of 2-propanol and allowed to stand overnight at 60°C. This washing procedure was repeated three times to obtain a hard gel of Comparative Example 1. The resulting hard gel was subjected to the above-mentioned catalytic activity test, but the hard gel of Comparative Example 1 showed no catalytic activity.

[0183] <Comparative Example 22> 3 mL of 2-hydroxyethyl methacrylate (HEMA) as the first precursor and 38 mg of 4,4'-azobis(4-cyanovaleric acid) as the polymerization initiator were added to 3.3 mL of aqueous acetic acid solution containing acetic acid at a concentration of 5 mmol / L and stirred until homogeneous. Next, 3 g of poly(oxyethylene) 2-ethylhexyl ether (Nonion EH-208, NOF Corporation) as a nonionic surfactant and 0.2 mL of tetramethylammonium hydroxide (TMAOH) at a concentration of 0.5 mol / L as a basic catalyst were added without adding the second precursor and stirred until homogeneous. Next, argon gas was introduced into the container containing the stirred solution, which was then sealed and heated to 60 °C to gel the entire mixture. The mixture was then left to age at 60 °C for 24 hours. Next, the aged gel was immersed in 100 mL of 2-propanol and left to stand at 60°C for 24 hours. This washing procedure was repeated three times to remove any unreacted components remaining inside the gel, thereby obtaining the hydrogel of Comparative Example 2.

[0184] <Comparative Examples 23 to 30> Hydrogels of Comparative Examples 23 to 30 were obtained in the same manner as in Comparative Example 22, except that the substances shown in Table 8 below were used instead of HEMA as the first precursor.

[0185] [Table 8]

[0186] The abbreviations in Table 8 are as follows: HEMA: 2-hydroxyethyl methacrylate PEGMA360: Poly(ethylene glycol) methacrylate / average molecular weight 360 (EO)2MA: Ethylene oxide methacrylate VyMA: vinyl methacrylate BzMA: benzyl methacrylate IPMA: Isopropyl methacrylate

[0187] The above-mentioned catalytic activity test was carried out on each of the hydrogels of Comparative Examples 22 to 30, but each hydrogel showed no catalytic activity whatsoever.

[0188] <Examples of supporting other metal species> Pd loading The same procedures as in Examples 36 and 37 were carried out, except that an aqueous acetic acid solution containing 30 mg of palladium acetate (the concentration of acetic acid was the same) was used instead of 454 mg of K2PtCl. As a result, hydrogels similar to those in Examples 36 and 37 could be prepared, except that Pd was supported instead of Pt.

[0189] Au-supported The same procedures as in Examples 36 and 37 were carried out, except that an aqueous acetic acid solution containing KAuCl4 (same acetic acid concentration) was used instead of K2PtCl4. As a result, hydrogels similar to those in Examples 36 and 37 were produced, except that Au was supported instead of Pt.

[0190] <Examples 55 to 64> The hydrogels of Examples 55 to 64 were obtained in the same manner as in Examples 36 and 37, except that the substances shown in Table 9 below were used as the first precursor and the second precursor, and an acetic acid aqueous solution containing 30 mg of palladium acetate (the concentration of acetic acid was the same) was used instead of 54 mg of KPtCl.

[0191] [Table 9]

[0192] The abbreviations in Table 9 are as follows: (First precursor) HEMA: 2-hydroxyethyl methacrylate BzMA: benzyl methacrylate IPMA: Isopropyl methacrylate AA: acrylic acid (EO)2MA: Ethylene oxide methacrylate (Second precursor) VTMS: vinyltrimethoxysilane DPPTES: 2-(diphenylphosphino)ethyltriethoxysilane APTES: 3-aminopropyltriethoxysilane N2TES: N-2-(aminoethyl)-3-aminopropyltriethoxysilane N3TES: 3-[2-(2-aminoethylamino)ethylamino]propyltriethoxysilane PTMS: Phenyltrimethoxysilane

[0193] The hydrogels of Examples 55 to 64 all contained a first polymer chain network A, which was polymer chains of a first precursor, a second polymer chain network B, which was polymer chains of a second precursor, and acetone as a liquid. Each hydrogel was always in a swollen state, including when immersed in a 2-propanol solution containing PMHS, 2-propanol, and acetone.

[0194] Furthermore, each hydrogel was visually confirmed to be transparent, and it was confirmed that Pd was retained inside the gel at sizes smaller than nanoparticles. Pd was estimated to be coordinated in the form of mononuclear or small clusters in Network A and Network B. The amount of Pd supported, calculated from the weight ratio of the materials used, was 1 wt% of the weight of each hydrogel.

[0195] <Evaluation> The hydrogels of Examples 55 to 64 were evaluated as follows.

[0196] [Catalytic activity test: Mizoroki-Heck coupling reaction] An arbitrary amount of hydrogel between 0.01 and 0.1 g was weighed into a glass bottle, and iodobenzene (0.204 g, 1.0 mmol), methyl methacrylate (0.0947 g, 1.1 mmol), diisopropylethylamine (0.194 g, 1.5 mmol), and 1 mL of dimethylformamide were added thereto. The bottle was sealed and reacted at 100°C for 0.5 hours. After the reaction, 10 μL of the supernatant was diluted with 1 mL of 2-propanol to prepare an analytical sample, which was then analyzed by HPLC to determine the progress of the reaction.

[0197] The HPLC analysis was carried out under the following measurement conditions. Mobile phase: Acetonitrile and water mixture (volume ratio 80:20) Mobile phase flow rate: 1.6 mL / min Column: GL Sciences Inertsil ODS-3 (φ3 × 100 mm) Column oven: 40℃ Sample injection volume: 1 μL Detector: UV-visible photodiode array detector

[0198] The following parameters were evaluated in the above analysis: Pdmol% Pdmol% is a value calculated by the formula: (number of moles of Pd in ​​the hydrogel catalyst / number of moles of iodobenzene before the start of the reaction) × 100 (%), and indicates the ratio of the number of atoms of the catalyst to the number of atoms of the substrate used in the reaction. Conversion rate The conversion rate is a value calculated by the formula: {[(number of moles of iodobenzene before the start of the reaction) - (number of moles of iodobenzene remaining after the reaction)] / number of moles of iodobenzene before the start of the reaction} × 100 (%), and indicates the ratio of the converted substrate to the substrate used in the reaction. Selectivity The selectivity is a value calculated by the formula: [number of moles of main product / (number of moles of main product+number of moles of by-products)]×100 (%), and indicates the ratio of the main product to all products produced by the reaction. Turnover number (TON) TON is a value calculated by the formula: (number of moles of iodobenzene before the reaction starts) / (number of moles of Pd in ​​the hydrogel catalyst) x conversion rate, and indicates the ratio of the substrate reacted per mole of Pd species. Turnover rate (TOF) TOF is a value calculated by the formula: TON×selectivity / reaction time, and indicates the ratio of the main reaction product obtained per mole of Pd species and per unit time.

[0199] [Method for measuring eluted Pd] The solution components after the catalytic activity test were filtered through a PTFE filter (pore size 0.22 μm) and placed in a glass container. The solvent was removed by heating at 160 °C under reduced pressure. 0.5 mL of aqua regia was added to the container after removal and allowed to react for 30 minutes to dissolve the residue in the container. The dissolved solution was diluted with purified water to a volume of 10 mL, and the amount of Pd eluted from the hydrogel during the Mizoroki-Heck coupling reaction was evaluated by inductively coupled plasma (ICP) emission spectroscopy of the resulting diluted solution.

[0200] The evaluation results are shown in Table 10 below.

[0201] [Table 10]

[0202] As shown in Table 10, each of the hydrogels in Examples 55 to 64 can be used as a heterogeneous catalyst and exhibited good catalytic activity for the Mizoroki-Heck coupling reaction. Furthermore, each hydrogel suppressed the amount of Pd leakage to almost zero to approximately 2 μg.

[0203] A reference example of the use of a conventional catalyst in the Mizoroki-Heck coupling reaction is shown below.

[0204] <Reference Example 5: Example using Pd-loaded activated carbon> The catalytic activity in the Mizoroki-Heck coupling reaction was evaluated by the same method as above, except that a Pd-loaded activated carbon catalyst (Sigma-Aldrich, Pd loading 5 wt%) was used instead of the hydrogel. The TON value was 50, and the TOF value was 10 l / h. The amount of eluted Pd evaluated by the above measurement method was 33.0 μg.

[0205] <Reference Example 6: Example using Pd-supported silica gel> The catalytic activity in the Mizoroki-Heck coupling reaction was evaluated using the same method as above, except that a Pd-loaded silica gel catalyst (Sigma-Aldrich, Pd loading 2 wt%) was used instead of hydrogel. The TON value was 238, and the TOF value was 476 / h. The amount of eluted Pd evaluated using the above measurement method was 3.7 μg. [Industrial Applicability]

[0206] The hydrogel of the present invention is expected to be applicable to various technical fields including the fields of catalysis and medicine.

Claims

1. a first polymer chain network A which is a polymer chain of a precursor having vinyl polymerizability; a second polymer chain network B having a siloxane bond in the main chain; Including, For carrying metal species, Hydrogel.

2. 2. The hydrogel according to claim 1, wherein the precursor is at least one selected from the group consisting of monosubstituted ethylenes, disubstituted ethylenes, and diene compounds.

3. The hydrogel according to claim 1, wherein the precursor is at least one selected from the group consisting of (meth)acrylic acid, (meth)acrylate, (meth)acrylamide, styrene, a styrene derivative, and isoprene.

4. The hydrogel of claim 1 , wherein the second polymer chain is a polysiloxane chain.

5. The hydrogel of claim 1 , wherein the hydrogel does not have any covalent bond points between the network A and the network B.

6. The hydrogel of claim 1 , wherein the hydrogel does not have macropores.

7. The hydrogel of claim 1 further comprising a metal species.

8. The hydrogel according to claim 7 , wherein the metal species is coordinated to at least one selected from the group consisting of the network A and the network B.

9. 8. The hydrogel of claim 7, wherein the metal species is a first transition series element, a second transition series element, or a third transition series element, or an alloy thereof.

10. The hydrogel of claim 7, wherein the metal species is Pd, Pt, Ag, Au, Rh, Ir, Re, Ru, Mn, Fe, Co, Ni, or Cu, or an alloy thereof.

11. A dried hydrogel according to any one of claims 1 to 10. Dried hydrogel.

12. A catalyst comprising the hydrogel according to any one of claims 7 to 10.

13. 13. The catalyst of claim 12 which is a hydrosilylation catalyst.

14. A solution system including a first precursor having vinyl polymerizability and a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, forming a hydrogel for supporting metal species, the hydrogel including the network A and the network B; Method for producing hydrogels.

15. The method for producing a hydrogel according to claim 14 , wherein the solvent of the solution system is hydrophilic.

16. the solution system further comprises a metal species; The method for producing a hydrogel according to claim 14 , further comprising forming the hydrogel further comprising the metal species.

17. The method of claim 16, further comprising reducing the metal species contained in the formed hydrogel.

18. 1. A method for producing a catalyst comprising a hydrogel containing a metal species, comprising: A solution system including a first precursor having vinyl polymerizability, a second precursor having a silicon atom to which two or more hydrolyzable functional groups are bonded, and a metal species, Proceeding polymerization of the first precursor and hydrolysis and polycondensation of the second precursor, A network A of first polymer chains, which are polymer chains of the first precursor, and a network B of second polymer chains, which are polymer chains of the second precursor and have siloxane bonds in their main chains, are formed together, forming a hydrogel comprising the network A and the network B, and the metal species; Catalyst manufacturing method.

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