Gas storage and release compounds

Abstract

To provide a novel gas storage-release compound and a novel gas storage-release material which enable various gases to be stored or released excellently.SOLUTION: A gas storage-release compound comprises a structural unit represented by the formula (1) and a structural unit represented by the formula (2) (In the formula (1), R1 is a C4-30 divalent alicyclic hydrocarbon group. In the formula (2), R2 is a C2-30 divalent aliphatic hydrocarbon group. The formula (1) is bound to the formula (2) through an amide bond, but structural units in the same formula are not directly bound to each other).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to gas storage and release compounds capable of storing and releasing gas. [Background technology]

[0002] In order to solve environmental problems such as global warming, efforts are underway to develop clean energy sources to replace fossil fuels. Among these, hydrogen is considered one of the most promising energy sources because it is a diverse and abundant resource, has good combustion performance characteristics and calorific value, and has a low environmental impact as it does not emit carbon dioxide when generating electricity using fuel cells or internal combustion engines.

[0003] To use hydrogen as an energy source, it is necessary to build a hydrogen storage and release system that can flexibly respond to fluctuating demand. For example, it is necessary to build a hydrogen supply chain that transports hydrogen obtained by electrolyzing water using surplus electricity to utilization facilities. However, because hydrogen is a gas at room temperature and pressure, it is currently stored as high-pressure hydrogen gas in containers such as tanks and cylinders. Therefore, to use hydrogen until now, high-pressure hydrogen or liquefied hydrogen had to be transported by tank truck. Furthermore, hydrogen storage facilities required the development of large-scale infrastructure such as high-pressure hydrogen gas tanks.

[0004] When using hydrogen on-site instead of a high-pressure hydrogen gas storage and release system using a container, hydrogen storage and release systems using hydrogen storage materials are being considered, which can safely store and release large amounts of hydrogen at low pressures through the interaction between hydrogen and the material. Hydrogen storage materials are materials that can selectively and reversibly store and release hydrogen. Hydrogen storage alloys are considered promising hydrogen storage materials, but there are problems with their hydrogen storage capacity. There is also room for improvement in terms of performance degradation due to impurity gases and increased costs associated with using rare metals and high-purity metals as raw materials. Furthermore, hydrogen storage alloys are difficult to process, and the densities of the titanium and manganese that make up the alloys are only 4-8 g / cm. 3Since the hydrogen storage capacity is high, the weight of the storage body is large, and cooling is required when storing hydrogen and heating is required when releasing hydrogen, which poses a problem in terms of handling.

[0005] The following patents have been filed as examples of hydrogen storage / release compounds: Patent Document 1 describes a method for storing hydrogen by forming a hydrogen storage layer on the surface of a porous body such as activated carbon by electroless plating, sputtering deposition, or the like, of an alloy layer of palladium, lanthanum, or the like. However, it is difficult to achieve the desired pore surface area of ​​the porous body, and it is also difficult to form a hydrogen storage alloy with a consistent thickness on the material surface, making the reproducibility of the hydrogen storage capacity unstable. Patent Document 2 describes a method in which a carbon compound primarily composed of graphene is crushed by rotating it in a container together with grinding media (steel balls, ceramic balls, steel ingots, etc.), and then a carbon-metal compound is synthesized by mechanical milling in which metal particles are mixed in, and the resulting compound is used as a hydrogen storage material. However, the pressure required for hydrogen storage is as high as 100 atmospheres, and manufacturing a hydrogen storage system requires a large amount of auxiliary equipment such as pumps and piping, making it difficult to put this system into practical use in society. Patent Document 3 describes the use of a porous (microporous) material consisting of carbon-carbon bonds obtained by utilizing the pores in zeolite as a hydrogen storage material. However, to obtain a porous (microporous) material, zeolite must be dissolved using hydrofluoric acid (HF). Hydrofluoric acid is a strong acid strong enough to dissolve glass, making it dangerous and difficult to handle, so it is only applicable to small amounts handled on a laboratory scale. Furthermore, hydrogen storage requires a high pressure of 100 atmospheres, which is not practical. Patent Document 4 claims that a compound in which boron is bonded to the carbon of graphene has a large hydrogen storage capacity, but since a high temperature of about 600°C is required to obtain the compound, a great deal of energy is required to synthesize the material. In addition, a pressure of 50 atmospheres is required to store hydrogen, and the behavior of hydrogen storage is irregular, making it difficult to control. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-18973 [Patent Document 2] Japanese Patent Application Publication No. 2018-172231 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-199428 [Patent Document 4] Special Publication No. 2020-521718 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a novel gas storage and release compound having excellent storage and release properties for various gases, and a gas storage and release material containing the gas storage and release compound. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that a gas storage / release compound having a specific structural unit and a gas storage / release material containing the gas storage / release compound have excellent storage / release properties for various gases, particularly hydrogen, and that the above-mentioned problems can be solved by using them.

[0009] That is, the present invention that solves the above problems mainly includes the following configurations. [Item 1] A gas storage and release compound having a structural unit represented by formula (1) and a structural unit represented by formula (2). [ka] [ka] (In formula (1), R 1 is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms. 2is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. Formula (1) and formula (2) are bonded by an amide bond, and structural units of the same formula are not directly bonded. [Item 2] The gas storage and release compound according to Item 1, wherein the gas storage and release compound has a network structure. [Item 3] A method for producing a gas storage / release compound, comprising reacting a polyamine compound containing at least an alicyclic diamine compound represented by formula (3) with a polycarboxylic acid compound containing at least an aliphatic dicarboxylic acid compound represented by formula (4). [ka] [ka] (In formula (3), R 1 is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms. 2 is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms, and X 1 and X 2 are each independently OH, halogen, or OR 3 (R 3 is an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different.) or NHR 4 (R 4 represents an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different. [Section 4] Item 1 or 2. A gas storage and release material comprising the gas storage and release compound. [Section 5] Item 5. The gas storage and release material according to item 4, wherein the gas is one or more selected from the group consisting of hydrogen, carbon dioxide, nitrogen, a noble gas, and a hydrocarbon gas. [Section 6] Item 6. The gas storage and / or release material according to item 4 or 5, wherein the gas is stored and / or released by a method comprising one or more means selected from the group consisting of pressurization, decompression, temperature increase, temperature decrease, application of electric potential, and irradiation with energy waves. [Section 7] Item 7. The gas storage and release material according to any one of Items 4 to 6, wherein the gas storage and release material is in the form of particles, fibers, a film, a nonwoven fabric, a woven fabric, a porous body, or a molded body. [Effects of the Invention]

[0010] The present invention provides a novel gas storage and release compound having excellent storage and release properties for various gases, and a gas storage and release material containing the gas storage and release compound. The gas storage and release compound of the present invention and the gas storage and release material containing the gas storage and release compound have particularly excellent hydrogen storage and release properties. The gas storage / release compound of the present invention and the gas storage / release material containing the gas storage / release compound can store larger amounts of hydrogen and have a lower density than hydrogen storage alloys. Furthermore, while hydrogen storage alloys require cooling to store hydrogen and heating to release hydrogen, the gas storage / release compound of the present invention and the gas storage / release material containing the gas storage / release compound require less energy when cooling to store hydrogen or when heating to release hydrogen, making it easier to control hydrogen storage and release.

[0011] The gas storage / release compound and gas storage / release material containing the gas storage / release compound of the present invention are polymeric materials obtained by a simple synthesis method using commercially available compound raw materials, making them inexpensive and highly versatile. Furthermore, because they are polymeric materials with a lower density than hydrogen storage alloys, they are easy to handle and enable efficient hydrogen transport. Furthermore, because the conditions for heating / cooling, pressurization / depressurization, etc. during hydrogen storage and release can be kept mild, they can be used under low energy usage. Furthermore, it is possible to safely and inexpensively establish a hydrogen supply chain in which hydrogen obtained by electrolyzing water using surplus electricity is sorbed inside a polymer storage tank, and the tank is loaded onto a truck and transported to a hydrogen utilization facility. In this case, the gas storage / release compound of the present invention and the gas storage / release material containing the gas storage / release compound are composed of a lightweight polymer material, which leads to reduced fuel costs during transportation and is easy to handle. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the hydrogen storage and release characteristics of a gas storage and release material containing a gas storage and release compound of the present invention and a hydrogen storage alloy. [Figure 2] FE-SEM (field emission scanning electron microscope) photograph of the surface of the gas storage and release compound of the present invention. [Figure 3] FIG. 1 is a diagram showing the endothermic behavior of the gas storage / release compound of the present invention during temperature increase using a differential scanning calorimetry (DSC). DETAILED DESCRIPTION OF THE INVENTION

[0013] The gas storage and release compound of the present invention and the gas storage and release material containing the same will be described below. [Gas storage and release compounds] The gas storage and release compound of the present invention has a structural unit represented by formula (1) and a structural unit represented by formula (2). [ka]

[0014] [ka] (In formula (1), R 1 is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms. 2 is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. Formula (1) and formula (2) are bonded by an amide bond, and structural units of the same formula are not directly bonded.

[0015] The structural unit represented by formula (1) can be based on, for example, an alicyclic diamine compound represented by formula (3). [ka] (In formula (3), R 1 is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms.

[0016] R in equation (3) 1 Examples of the divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms include a cycloalkylene group and a cycloalkylidene group. The number of carbon atoms in the divalent alicyclic group is 4 to 30, preferably 5 to 15, and more preferably 5 to 10. As the divalent alicyclic hydrocarbon group, for example, one or more groups independently selected from the group consisting of a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecalene group, a methylcyclohexylene group, a methylenebis(cyclohexyl) group, a cyclohexanediylbis(methylene) group, a norbornene group, an adamantylene group, a norbornane group, a tetracyclodecalene group, and the like are preferred for each repeating unit. 1 When R is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms, a space of an appropriate size for storing gas can be formed within the molecule, thereby increasing the gas storage and release capacity. 1 If the number of carbon atoms exceeds 30, the resulting gas storage and release compound may be gel-like, and the specific surface area of ​​the resulting gas storage and release compound may be small, which may result in a decrease in hydrogen storage rate.

[0017] The alicyclic diamine compound represented by formula (3) may be a commercially available product or may be synthesized. In the present invention, it is preferable to use one or more compounds selected from the group consisting of 1,2-diaminocyclopentane, 1,3-diaminocyclopentane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,2-diaminocycloheptane, 1,3-diaminocycloheptane, 1,2-diaminocyclooctane, 1,5-diaminocyclooctane, isophoronediamine, norbornanediamine, 4,4'-diaminodicyclohexylmethane, 1,3-diaminoadamantane, bis(aminomethyl)norbornane, 4,4'-methylenebis(2-methylcyclohexane-1-amine), decahydro-1,4-naphthalenediamine, and 4,4'-oxobis(cyclohexane-1-amine). Particularly preferably, one or more selected from the group consisting of 1,2-diaminocyclopentane, 1,2-diaminocyclohexane, 1,2-diaminocycloheptane, 1,3-diaminoadamantane, bis(aminomethyl)norbornane, and the like can be used.

[0018] The structural unit represented by formula (2) can be obtained, for example, from an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof. [ka] (In formula (4), R 2 is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms, and X 1 and X 2 are each independently OH, halogen, or OR 3 (R 3 is an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different.) or NHR 4 (R 4 represents an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different.

[0019] R in equation (4) 2The divalent aliphatic hydrocarbon group having from 2 to 30 carbon atoms includes a linear aliphatic hydrocarbon group or a branched aliphatic hydrocarbon group, for example, a linear alkylene group or a branched alkylene group. The number of carbon atoms in the divalent aliphatic hydrocarbon group is from 2 to 30, preferably from 4 to 18, and more preferably from 8 to 16. Examples of the divalent alicyclic hydrocarbon group include, independently for each repeating unit, -(CH2)2-, -(CH2)3-, -CH(CH3)CH2-, -CH2-C(CH3)2-CH2-, -(CH2)4-, -(CH2)6-, -(CH2)8-, -(CH2) 10 -, -(CH2) 12 -, -(CH2) 18 -, -(CH2) 24 -, etc. 2 When R is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms, a space of an appropriate size for storing gas can be formed within the molecule, thereby increasing the gas storage and release capacity. 2 If the number of carbon atoms in R is less than 2, the gas storage / release compound is easily oxidized, and the specific surface area becomes small, which may result in a decrease in the hydrogen storage rate. 2 If the number of carbon atoms exceeds 30, the internal high-order structure of the resulting gas storage / release compound may be lost, and the hydrogen storage rate may decrease.

[0020] The aliphatic dicarboxylic acid compound represented by formula (3) may be a commercially available product or may be synthesized. In the present invention, one or more polycarboxylic acid compounds selected from the group consisting of succinic acid, methylmalonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, hexadecanedioic acid, pentadecanedioic acid, hexadecenedioic acid, octadecanedioic acid, octadecenedioic acid, eicosenedioic acid, eicosenedioic acid, docosenedioic acid, diglycolic acid, 2,2,4- / 2,4,4-trimethyladipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, and tetradecanedioic acid, or reactive derivatives thereof (such as acid halides, esters, amidations, and acid anhydrides) may be used.

[0021] The gas storage / release compound of the present invention may contain copolymerized units in addition to the structural units represented by formulas (1) and (2). Examples of copolymer units that the gas storing and releasing compound of the present invention may contain include those represented by the following formulas (5) to (7), other than the structural units represented by formula (1) or (2). -HN-R 5 (-NH-) w ···(5) -OC-R 6 (-CO-) x ···(6) (-HN-) y R 7 (-CO-) z ···(7) (In formulas (5) to (7), w is an integer of 1 to 3, x is an integer of 1 to 3, y is 1 or 2, and z is 1 or is 2, R 5 is a w+1 valent organic group, R 6 is an organic group with a valence of x+1, R 7 is an organic group with a valence of y+z. Note that formula (5) is not the same as formula (1), and formula (6) is not the same as formula (2). The structural units represented by formula (1), formula (2), and formulas (5) to (7) are bonded together by forming an amide bond (-HN-CO- or >N-CO-). In the present invention, the structural unit represented by formula (5) can be obtained from a polyamine compound that does not constitute the structural unit represented by formula (1), the structural unit represented by formula (6) can be obtained from a polycarboxylic acid or a reactive derivative thereof that does not constitute the structural unit represented by formula (2), and the structural unit represented by formula (7) can be obtained from a (di)amino(di)carboxylic acid, a reactive derivative thereof, or a lactam.

[0022] R 5 , R 6 and R 7Examples of the groups independently include a divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and an aromatic heterocyclic group having 6 to 20 carbon atoms and containing N and / or O and / or S. Preferred examples of the groups independently include an alkylene group, a phenylene group, etc. having 2 to 6 carbon atoms.

[0023] R is a w+1 valent organic group in formula (5) 5 Examples of the aromatic diamines include 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2,6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino-1,2-diphenylethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, and 3,3'-diaminodiphenyl sulfone; ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, and 1,6-hexanediamine. It is preferable that the compound is based on one or more polyamine compounds selected from the group consisting of aliphatic diamines such as diamines, 1,7-heptanediamine, 1,9-nonanediamine, 1,12-dodecamethylenediamine, and metaxylenediamine; heterocyclic diamines such as piperazine; polyamine phenols such as 2,2-bis(3-amino-4-hydroxyphenyl)propane, 9,9-bis(3-amino-4-hydroxyphenyl)fluorene, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; and polyfunctional amines such as 1,2,4-triaminobenzene, 3,4,4'-triaminodiphenyl ether, tris(2-aminoethyl)amine, tris(3-aminotrimethylene)amine, tris(4-aminobutyl)amine, tris(6-aminohexyl)amine, and tris(aminopropyl)amine.

[0024] R is an organic group with a valence of x+1 in formula (6). 6 Examples of the dibasic acids include aromatic dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and 2,7-pyrenedicarboxylic acid; aliphatic dibasic acids such as oxalic acid, maleic acid, fumaric acid, malic acid, tartaric acid, thiomalic acid, and diglycolic acid; alicyclic dibasic acids such as 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, dicyclohexanemethane-4,4'-dicarboxylic acid, and norbornanedicarboxylic acid; trimellitic acid, 1,2,3-benzenetricarboxylic acid, trimesic acid, hemilic acid, 1,2,4-naphthalenetricarboxylic acid, and 1,4,5-naphthalenetricarboxylic acid.

[0049] Preferred are groups derived from one or more polycarboxylic acid compounds selected from the group consisting of anthracene tricarboxylic acid, 1,3,6-naphthalene tricarboxylic acid or 2,3,6-naphthalene tricarboxylic acid, 1,2,8-naphthalene tricarboxylic acid, 2,3,6-anthracene tricarboxylic acid, 3,4,4'-benzophenone tricarboxylic acid, 3,4,4'-biphenyl ether tricarboxylic acid, 3,4,4'-biphenyl tricarboxylic acid, 2,3,2'-biphenyl tricarboxylic acid, 3,4,4'-biphenyl methane tricarboxylic acid, 3,4,4'-biphenyl sulfone tricarboxylic acid, hydrogenated trimellitic acid, pyromellitic acid, hydrogenated pyromellitic acid, benzophenone tetracarboxylic acid, and the like, or reactive derivatives thereof (acid halides, esterified products, amidated products, acid anhydrides, etc.).

[0025] R is an organic group with a valence of y+1 in formula (7). 7Preferred examples of the carboxylic acid include one or more (di)amino(di)carboxylic acids selected from the group consisting of 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminocapric acid, 11-aminoundodecanoic acid, aminobenzoic acid, diaminobenzoic acid, 1,5-diamino-2,4-dicarboxylbenzene, ε-caprolactam, ω-enantholactam, ω-undecalactam, ω-laurolactam, α-pyrrolidone, α-piperidone, and the like, reactive derivatives thereof, and groups derived from lactams.

[0026] The gas storage / release compound of the present invention may be composed only of the structural unit represented by formula (1) and the structural unit represented by formula (2), or may contain one or more structural units represented by formulas (5) to (7) in addition to the structural unit represented by formula (1) and the structural unit represented by formula (2). The content of the structural unit represented by formula (1) relative to the total amount of all structural units in the gas storage / release compound (structural units represented by formula (1), structural units represented by formula (2), structural units represented by formula (5), structural units represented by formula (6), and structural units represented by formula (7), hereinafter, these may be collectively referred to as "all structural units") is, for example, 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and for example, 60 mol% or less, preferably 50 mol% or less. If it is less than 1 mol% or more than 60 mol%, the gas storage / release properties may be reduced.

[0027] The content of the structural unit represented by formula (2) relative to the total amount of all structural units in the gas storage / release compound is, for example, 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and for example, 60 mol% or less, preferably 50 mol% or less. If it is less than 1 mol% or exceeds 60 mol%, the gas storage / release properties may be reduced.

[0028] The content of the structural unit represented by formula (5) relative to the total amount of all structural units in the gas storage / release compound is, for example, 30 mol% or less, preferably 20 mol% or less, more preferably 10 mol% or less. If it exceeds 30 mol%, the gas storage / release properties may be reduced. The content of the structural unit represented by formula (6) relative to the total amount of all structural units in the gas storage / release compound is, for example, 30 mol% or less, preferably 20 mol% or less, more preferably 10 mol% or less. If it exceeds 30 mol%, the gas storage / release properties may be reduced. The content of the structural unit represented by formula (7) relative to the total amount of all structural units in the gas storage / release compound is, for example, 40 mol% or less, preferably 20 mol% or less, more preferably 10 mol% or less. If it exceeds 40 mol%, the gas storage / release properties may be reduced.

[0029] The weight-average molecular weight of the gas storage / release compound of the present invention is not particularly limited, but is, for example, 5,000 or more, preferably 10,000 or more, and for example, 3,000,000 or less, preferably 2,000,000 or less, and more preferably 1,500,000 or less. If the weight-average molecular weight is less than 5,000, the gas storage / release compound may become liquid, and the gas may be adsorbed only on the surface of the gas storage / release compound, resulting in a decrease in storage / release capability. If the weight-average molecular weight exceeds 3,000,000, the compound may become brittle due to hydrogen gas, and the chemical stability of the gas storage / release compound may be lost.

[0030] [Method for producing gas storage and release compounds] The gas storage / release compound of the present invention can be obtained by reacting at least a polyamine component containing an alicyclic diamine compound represented by formula (3) with a polycarboxylic acid component containing an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof, using a known polyamide polymerization reaction means.

[0031] [ka] (In formula (3), R1 is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms.

[0032] [ka] (In formula (4), R 2 is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms, and X 1 and X 2 are each independently OH, halogen, or OR 3 (R 3 is an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different.) or NHR 4 (R 4 represents an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different.

[0033] <Polyamine ingredient> The alicyclic diamine compound represented by formula (3) contained in the polyamine component is the same as the alicyclic diamine compound represented by formula (3) that constitutes the structural unit represented by formula (1). Furthermore, the polyamine or reactive derivative thereof other than the alicyclic diamine compound represented by formula (3), which may be contained in the polyamine component, is, for example, a polyamine compound constituting a structural unit represented by formula (5).

[0034] The content of the alicyclic diamine compound represented by formula (3) in the polyamine component is, for example, 10 mol% or more, preferably 50 mol% or more and 100 mol% or less. If it is less than 10 mol%, the gas storage space in the polymer structure will be reduced, which may result in a decrease in gas storage and release properties.

[0035] <Polycarboxylic acid component> The aliphatic dicarboxylic acid compound represented by formula (4) or its reactive derivative contained in the polycarboxylic acid component is the same as the aliphatic dicarboxylic acid compound represented by formula (4) constituting the structural unit represented by formula (2). In the present invention, it is preferable to use an aliphatic dicarboxylic acid halide as the aliphatic dicarboxylic acid compound represented by formula (4) or its reactive derivative from the viewpoint of reactivity, etc. Furthermore, the polycarboxylic acid or its reactive derivative other than the aliphatic dicarboxylic acid compound represented by formula (4) or its reactive derivative, which may be contained in the polycarboxylic acid component, is, for example, a polycarboxylic acid compound constituting a structural unit represented by formula (6).

[0036] The content of the aliphatic dicarboxylic acid compound represented by formula (4) or its reactive derivative in the polycarboxylic acid component is, for example, 10 mol% or more, preferably 50 mol% or more and 100 mol% or less. If it is less than 10 mol%, the gas storage space in the polymer structure will be reduced, which may result in a deterioration in gas storage and release properties.

[0037] <Other reaction components> In the present invention, in addition to the polycarboxylic acid component and the polyamine component, (di)amino(di)carboxylic acid compounds (diaminocarboxylic acid compounds, diaminodicarboxylic acid compounds, aminodicarboxylic acid compounds), lactams, etc. can be used as other reaction components as needed during the polyamide polymerization reaction. The (di)amino(di)carboxylic acid and lactam are, for example, (di)amino(di)carboxylic acid and lactam constituting the structural unit represented by formula (7).

[0038] <Reaction ratio of each component> In the present invention, the reaction molar ratio of the polyamine component containing the alicyclic diamine compound represented by formula (3) to the polycarboxylic acid component containing the aliphatic dicarboxylic acid compound represented by formula (4) or its reactive derivative is, for example, 0.8 moles or more, preferably 0.9 moles or more, more preferably 0.95 moles or more, and for example, 1.7 moles or less, preferably 1.6 moles or less, more preferably 1.45 moles or less, per mole of the alicyclic diamine compound represented by formula (3). If the amount of the polycarboxylic acid component containing the aliphatic dicarboxylic acid compound represented by formula (4) or its reactive derivative is more than 1.7 moles or less than 0.8 moles, the molecular weight of the gas storage / release compound may not be sufficiently large, and the gas storage / release properties may be reduced.

[0039] [Polymerization method] In the present invention, a known polyamide polymerization reaction means can be used as a method for reacting at least a polyamine component containing an alicyclic diamine compound represented by formula (3) with a polycarboxylic acid component containing an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof. for example, (i) A method of converting an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof into an aromatic tricarboxylic acid chloride and reacting the resulting aromatic tricarboxylic acid chloride with a polyamine component containing an alicyclic diamine compound represented by formula (3); (ii) A method in which an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof is converted into a dicarboxylic acid diester and reacted with a polyamine component containing an alicyclic diamine compound represented by formula (3) in the presence of a metal catalyst; (iii) A method in which an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof is converted into a dicarboxylic acid and reacted with a polyamine component containing an alicyclic diamine compound represented by formula (3) in the presence of a carbodiimide catalyst; Examples include: In the present invention, it is preferable to use a method in which an aliphatic dicarboxylic acid compound represented by formula (4) or a reactive derivative thereof is converted into a dicarboxylic acid chloride and reacted with a polyamine component containing an alicyclic diamine compound represented by formula (3).

[0040] The gas storage / release compound of the present invention has a network structure because it contains a structural unit represented by formula (1) and a structural unit represented by formula (2). It is speculated that this network structure acts like a wall that holds hydrogen molecules, thereby exhibiting the function of storing and releasing gas, for example, hydrogen molecules (hydrogen gas), but the present invention is not limited by this speculation.

[0041] [Gas storage and release materials] The gas storage / release material of the present invention contains one or more of the gas storage / release compounds in an amount of 1 to 100% by mass, preferably 10 to 100% by mass, and more preferably 50 to 100% by mass. If the content of the gas storage / release compound is less than 1% by mass, the gas storage properties may not be fully exhibited. Examples of components other than the gas storage and release compound having structural units represented by formulas (1) and (2) that may be contained in the gas storage and release material of the present invention include resins, fillers, various additives, etc.

[0042] The resin is not particularly limited, but examples thereof include polyolefin resins, polyester resins, acrylic resins, polyamide resins, urethane resins, etc. The filler is not particularly limited, but examples thereof include silica, talc, clay, calcium carbonate, barium sulfate, titanium oxide, glass flakes, carbon fiber, glass fiber, metal fiber, organic fiber, organic nanofiber, inorganic nanofiber, metal nanofiber, etc. The various additives are not particularly limited, but examples thereof include colorants such as organic pigments, inorganic pigments, and dyes, adsorbents such as zeolite and activated carbon, plasticizers, antibacterial agents, and conductive materials.

[0043] The gas storage and release material may have any shape, such as particles, fibers, films, nonwoven fabrics, woven fabrics, porous bodies, molded bodies, and the like. In the case of particles, the average particle diameter can be arbitrarily adjusted within the range of, for example, 0.1 μm to 20 mm. The average particle diameter of the gas storage / release material in the present invention is the volume-based cumulative particle diameter D at 50% cumulative volume by a laser diffraction / scattering particle size distribution measurement method. 50 is the value. In the case of fibers, the length can be adjusted arbitrarily within the range of 1 mm to 3 m, the diameter of 0.1 mm to 5 mm, and the denier number of 0.5 d to 20 d. In the case of a film, the thickness can be adjusted arbitrarily within the range of, for example, 2 μm to 5 mm. The width and length of the film can be arbitrarily set. In the case of nonwoven or woven fabric, for example, the basis weight is 5 g / m 2 ~200g / m 2 It can be adjusted arbitrarily within the range. In the case of a porous body, for example, an apparent density of 0.1 g / m 3 ~1.2g / m 3 The porosity can be adjusted arbitrarily within the range of 5 to 80 vol %. In the case of a molded article, any molding means such as extrusion molding or injection molding may be used to prepare a molded article of any shape. The gas storage / release material of the present invention is preferably in the form of particles, porous bodies, nonwoven fabrics, films, or fibers, from the viewpoints of ease of production, adjustment of the area in contact with gases such as hydrogen, and improved handling.

[0044] [Gas] The gas (gas) stored and released by the gas storage / release compound or gas storage / release material of the present invention is not particularly limited. Examples include one or more gases selected from the group consisting of hydrogen, carbon dioxide, nitrogen, rare gases (helium, neon, argon, krypton, radon), hydrocarbon gases (methane, ethane, propane, butane, acetylene, etc.), oxygen, and halogen gases (fluorine, chlorine). Preferably, the gas is one or more gases selected from the group consisting of hydrogen, nitrogen, carbon dioxide, argon, methane, ethane, propane, and acetylene, and particularly preferably hydrogen.

[0045] [Gas storage and release method] The method for storing (associating) and releasing (desorbing) a gas (gas) in the gas storage / release compound or gas storage / release material of the present invention can be a known method for storing and releasing hydrogen in a gas storage / release compound or gas storage / release material, particularly a hydrogen storage material. For example, the method may include one or more means selected from the group consisting of pressurization, decompression, temperature increase (heating), temperature decrease (cooling), application of electric potential, and irradiation with energy waves such as ultraviolet rays, infrared rays, and electromagnetic waves.

[0046] The storage means is preferably a method including one or more means selected from the group consisting of pressurization, depressurization, temperature increase (heating), temperature decrease (cooling), application of electric potential, and ultraviolet irradiation, and more preferably a method including one or more means selected from the group consisting of pressurization, depressurization, temperature increase (heating), and temperature decrease (cooling). In the present invention, a method including pressurization means is particularly preferred. The releasing means is preferably a method including one or more means selected from the group consisting of decompression, pressurization, temperature increase (heating), temperature decrease (cooling), application of electric potential, and ultraviolet irradiation, and more preferably a method including one or more means selected from the group consisting of decompression, pressurization, temperature increase (heating), and temperature decrease (cooling). In the present invention, a method including a decompression means is particularly preferred.

[0047] [Use of gas storage and release compounds or gas storage and release materials] The gas storage / release compound or gas storage / release material of the present invention can safely store a gas at room temperature (25°C ± 20°C) under atmospheric pressure for a long period of time and can release the stored gas by a simple means. The gas storage / release compound or gas storage / release material of the present invention is particularly useful as a hydrogen storage material because it can safely store hydrogen at room temperature (25°C ± 20°C) under atmospheric pressure for a long period of time and can release the stored hydrogen by a simple means. Furthermore, the alloy exhibits excellent hydrogen storage and release properties even under low pressure conditions below atmospheric pressure, where hydrogen storage alloys do not exhibit such properties, and from this point of view, the alloy is also useful as a hydrogen storage material. Furthermore, due to its excellent moldability, it can be easily processed into any shape, and due to its light weight, it can be easily transported and stored.

[0048] For example, electricity generated at a wind power plant is used to produce hydrogen in a water electrolysis hydrogen production device, and the hydrogen is stored in the gas storage / release compound or gas storage / release material of the present invention housed in an on-board container. The container containing the gas storage / release compound or gas storage / release material with stored hydrogen is loaded onto a vehicle and transported to a hot spring facility equipped with a hydrogen storage material tank and a pure hydrogen fuel cell, and hydrogen is transferred from the gas storage / release compound or gas storage / release material to these facilities. The electricity and hot water generated by the fuel cell will be used in the hot spring facility, and "heat cascade utilization" will be implemented during hydrogen transport, with the heat generated on the hydrogen storage side being used to heat the hydrogen release side. Furthermore, the heat required to release hydrogen from the hydrogen storage material tank can be provided by utilizing low-temperature waste heat from the building, improving energy efficiency. [Example]

[0049] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0050] [Synthesis of gas storage and release compounds] Example 1 A 200 ml round-bottom flask was charged with 5 ml of N,N-dimethylformamide, followed by the addition of 3.00 g of dodecane dioyl dichloride (molecular weight 267; 0.011 mol) and 1.25 g of 1,2-diaminocyclohexane (cis- and trans-mixture) (molecular weight 114; 0.11 mol). The mixture was stirred at 25°C for 1 hour. Next, 4 ml of 10% aqueous ammonia was added until the pH reached 7 on pH test paper. The precipitate was collected by suction filtration using a G3 glass filter, and washed with 10 ml of water added three times over the filter cake. After adding 5 ml of acetone, the mixture was air-dried for 1 hour. The resulting solid was then vacuum-dried at 80°C for 1 day using a vacuum dryer (Yamato Scientific, Model DP200) to obtain a gas storage-release compound.

[0051] <Structural analysis> (FT-IR) The FT-IR of the obtained gas storage / release compound was measured by the single reflection ATR method using a Fourier transform infrared spectrophotometer FT / IR-6800 manufactured by JASCO Corporation. The results are as follows. CO: 1735, 1774 (cm -1 ) CH2: 1490, 2926, 2989 (cm -1 ) NH: 1756, 1792 (cm -1 ) COC: 1636, 1692 (cm -1 )

[0052] (Weight average molecular weight) For the obtained gas storage / release compound, a gel permeation chromatography (GPC) apparatus manufactured by Shimadzu Corporation was equipped with an HPLC column Shim-pack GPC-805 manufactured by Shimadzu GLC Co., Ltd., and the gas storage / release compound dissolved in N,N'-dimethylformamide solvent was injected and the column retention time was measured. From the obtained column retention time, the polystyrene-equivalent molecular weight was calculated by comparison with a calibration curve prepared in advance by measuring polystyrene whose molecular weight was known.

[0053] The gel permeation chromatography device manufactured by Shimadzu Corporation has the following configuration: ·system Nexera GPC System System Controller CBM-40 Liquid delivery unit LC40D Online degassing unit DGU-403 Autosampler SIL-40C Column oven CTO-40C Detector RID-20ABLK, LabSolutions GPC software, LC workstation PC, LabSolutions LC Single LC ·column Shim-pack GPC-805 ·solvent N,N'-dimethylformamide

[0054] (Structural analysis results) From the results of these FT-IR and weight average molecular weight measurements, it was confirmed that the gas storage / release compound according to the example was a network polyamide compound having at least the following two types of structural units (1A) and (2A), in which these structural units were linked in a network form by amide bonds, and having a weight average molecular weight of 186,000. [ka] [ka]

[0055] <Evaluation of hydrogen storage and release capacity> The hydrogen storage and release capacity was evaluated using the PCT (Pressure Composition Temperature) method. The test powder was filled into a stainless steel sample tube, and the PCT (Hydrogen Pressure-Composition-Isomers) measurement device (Suzuki Shokan, PCT-4SDWIN) was used to observe the PCT curve at 25°C. The PCT characteristic measurement device, also known as a Sieverts apparatus, measures the characteristics (P: pressure, C: storage amount (absorption amount), T: temperature) when a substance absorbs and releases hydrogen. The relationship between the pressure and the amount of hydrogen stored (Adsorption: mass %) and released (Desorption: mass %) of the gas storage and release compounds according to the examples is shown in Figure 1. The storage amount and release amount referred to here are the amount of hydrogen stored (absorption) or released relative to the mass of the gas storage and release compound, expressed as mass %. As a result, it was found that the gas storage / release compound having a network structure synthesized in Example 1 had a higher hydrogen storage capacity than the graphene oxide of the comparative example.

[0056] <Scanning electron microscope observation> The resulting powder of the gas storage / release compound was dried in a vacuum at 40°C for 1 hour, and then an observation sample was prepared using a dispersion method. The surface of the gas storage / release compound was observed using a field emission scanning electron microscope (FE-SEM). The results are shown in Figure 2. From Figure 2, it can be seen that there are many pores of about 30 nm to 100 nm on the surface of the polymer particles, and it can be inferred that gas molecules are adsorbed into the interior of the polymer chains through these pores. The conditions for the scanning electron microscope observation are as follows: Field emission scanning electron microscope Zeiss Merlin Applied voltage 0.8kV Sample preparation The sample was dried at 40°C (in vacuum) for 1 hour, and then subjected to a dispersion method to prepare an observation sample.

[0057] <Endothermic behavior during temperature rise> The endothermic behavior of the obtained gas storage / release compound during heating was observed using a differential scanning calorimetry (DSC), and the results are shown in Figure 3. As shown in Figure 3, endothermic events were observed at 90°C and 270°C, indicating a phase transition phenomenon in the internal structure of the polymer. From this, it can be inferred that the gas storage / release compound has a higher-order structure, forming a hydrogen-encapsulating space.

[0058] The conditions for observing the endothermic behavior during temperature rise are as follows: ·DSC device SII Nano Technology DSC7020 Temperature range Room temperature~300℃ Heating rate 10℃ / min Atmospheric gas N2

[0059] <Comparative Example> 50 ml of a palladium chloride aqueous solution (5% by mass in 10% by mass HCl) was diluted 10-fold in a volumetric flask, and 30 ml of the solution was poured into a 200 ml round-bottom flask. 3.0 g of graphene oxide was added, and the round-bottom flask was immersed in an ultrasonicator (AS ONE dual-frequency, resin-cased type MCD-2P) and ultrasonicated for 2 hours. Then, 1% aqueous ammonia was added dropwise to the round-bottom flask until the pH indicator paper indicated a pH of 7. The entire solution was filtered through a G3 glass filter and washed with 10 ml of water. The resulting powder was placed in a Kenis Co., Ltd. MT-90mm pot mill, mounted on an AS ONE benchtop pot mill stand PM-001 2-7816-01, and processed at 300 rpm for 2 hours to obtain graphene oxide. The obtained graphene oxide was separated using a sieve (Tokyo Screen, test sieve JTS-200-45-48, mesh: plain weave, mesh size: 0.053 mm) to prepare a sample for evaluating hydrogen storage / release capacity. The hydrogen storage and release capacity of the obtained sample for evaluating hydrogen storage and release capacity was evaluated in the same manner as in Example 1. The results are also shown in Figure 1. As a result, the gas storage compound of Example 1 (gas storage and release material containing it) exhibited higher hydrogen storage and release capacity than the graphene oxide of Comparative Example 1.

[0060] The inventors speculate as follows about the reason why the gas storage and release properties of the gas storage and release compounds of the Examples are high. Graphene oxide is a carbon compound formed by stacking layers of six-membered rings consisting of carbon-carbon bonds that are spread two-dimensionally. The distance between layers is in the range of 0.5 to 2.0 nm, and it can capture hydrogen molecules by applying a pressure of 10 MPa or more. On the other hand, the gas storage / release compound of the present invention is a polymer in which aromatic rings having π electron clouds are arranged in a network pattern, and hydrogen molecules can easily enter the interior of the polymer structure. It is presumed that hydrogen molecules are polarized into δ+ and δ- by the π electrons, and that this allows the hydrogen molecules to be easily captured inside the polymer structure (between the aromatic rings) due to the interaction between the π electron clouds, even under pressure of about 1 MPa. However, the present invention is not limited to this presumption.

[0061] These results demonstrate that the gas storage / release compound of the present invention and the gas storage / release material containing it have a higher mass % of hydrogen storage (absorption) and release relative to the mass of the gas storage / release compound, and thus a higher hydrogen storage / release capacity, compared to the graphene oxide of the comparative example. This confirms that the gas storage / release compound of the present invention and the gas storage / release material containing the same are useful as materials capable of storing and releasing gas, particularly hydrogen.

Claims

1. A gas storage / release compound having a network structure and a structural unit represented by formula (1) and a structural unit represented by formula (2). 【Chemical 1】 【Chemistry 2】 (In formula (1), R １ is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms. ２ is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. Formula (1) and formula (2) are bonded by an amide bond, and structural units of the same formula are not directly bonded.

2. A gas storage and release compound having a structural unit represented by formula (1) and a structural unit represented by formula (2). 【Chemistry 3】 【Chemistry 4】 (In formula (1), R 1 is based on one or more alicyclic diamine compounds selected from the group consisting of 1,2-diaminocyclopentane, 1,3-diaminocyclopentane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,2-diaminocycloheptane, 1,3-diaminocycloheptane, 1,2-diaminocyclooctane, 1,5-diaminocyclooctane, isophoronediamine, norbornanediamine, 4,4'-diaminodicyclohexylmethane, 1,3-diaminoadamantane, bis(aminomethyl)norbornane, 4,4'-methylenebis(2-methylcyclohexane-1-amine), decahydro-1,4-naphthalenediamine, and 4,4'-oxobis(cyclohexane-1-amine). In formula (2), R 2 is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. Formula (1) and formula (2) are bonded by an amide bond, and structural units of the same formula are not directly bonded.

3. A method for producing a gas storage-release compound having a network structure, comprising reacting a polyamine compound containing at least an alicyclic diamine compound represented by formula (3) with a polycarboxylic acid compound containing at least an aliphatic dicarboxylic acid compound represented by formula (4). 【Chemistry 5】 【Chemistry 6】 (In formula (3), R １ is a divalent alicyclic hydrocarbon group having 4 to 30 carbon atoms. ２ is a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms, and X １ and X ２ are each independently OH, halogen, OR ３ (R ３ represents an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different. ４ (R ４ represents an alkyl group having 1 to 6 carbon atoms, and when there are a plurality of alkyl groups, they may be the same or different.

4. A method for producing a gas storage / release compound, comprising reacting a polyamine compound containing at least an alicyclic diamine compound represented by formula (3) with a polycarboxylic acid compound containing at least an aliphatic dicarboxylic acid compound represented by formula (4), wherein the alicyclic diamine compound represented by formula (3) is selected from the group consisting of 1,2-diaminocyclopentane, 1,3-diaminocyclopentane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,2-diaminocycloheptane, and 1,3-diaminocyclohexane. the gas storage-and-release compound is one or more selected from the group consisting of norbornanediamine, 4,4'-diaminodicyclohexylmethane, 1,3-diaminoadamantane, bis(aminomethyl)norbornane, 4,4'-methylenebis(2-methylcyclohexane-1-amine), decahydro-1,4-naphthalenediamine, and 4,4'-oxobis(cyclohexane-1-amine). 【Chemistry 7】 【Chemistry 8】 In formula (4), R 2 is a divalent aliphatic hydrocarbon group having from 2 to 30 carbon atoms, and X 1 and X 2 each independently represent OH, halogen, OR 3 (R 3 is an alkyl group having 1 to 6 carbon atoms, and when there are multiple R 3 s, they may be the same or different), or NHR 4 (R 4 is an alkyl group having 1 to 6 carbon atoms, and when there are multiple R 4 s, they may be the same or different).

5. A gas storage and release material comprising the gas storage and release compound of claim 1 or 2.

6. 6. The gas storage and release material according to claim 5, wherein the gas is at least one selected from the group consisting of hydrogen, carbon dioxide, nitrogen, a noble gas, and a hydrocarbon gas.

7. 7. The gas storage and / or release material according to claim 5 or 6, wherein the gas is stored and / or released by a method comprising one or more means selected from the group consisting of pressurization, depressurization, temperature increase, temperature decrease, application of electric potential, and irradiation with energy waves.

8. 8. The gas storage and release material according to claim 5, which is in the form of particles, fibers, a film, a nonwoven fabric, a woven fabric, a porous body, or a molded body.

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