Humidifying material and device

Abstract

A humidity control material containing a salt composed of a pyrazolium cation represented by formula (N1) and a phosphate anion. In formula (N1), RN1, RN2, RN3, RN4, and RN5 are each independently a hydrogen atom, or an alkyl group having 1-12 carbon atoms, which has or does not have a hydroxyl group and which contains or does not contain one or more oxygen atoms in the chain. And at least one of RN1 and RN2 substituted on a nitrogen atom constituting the five-membered ring is an alkyl group having 1-12 carbon atoms, which has or does not have a hydroxyl group and which contains or does not contain one or more oxygen atoms in the chain. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a humidity-controlling material used in, for example, an air conditioner or an absorption refrigerator, and to devices such as the air conditioner or the absorption refrigerator. Background Art

[0002] In a dehumidifying air conditioner, a liquid humidity-controlling material having the property of absorbing water vapor in the air is used. Non-patent documents 1 to 2 disclose liquid humidity-controlling materials using lithium chloride aqueous solution, calcium chloride aqueous solution, and triethylene glycol. Patent documents 1 to 4 and non-patent documents 3 to 7 disclose liquid humidity-controlling materials using ionic liquids, and as the above-mentioned ionic liquids, salts of bromide anions and tetrafluoroborate, dimethyl phosphate anions, methylsulfate anions and imidazolium cations, alkylphosphonium cations, quaternary ammonium cations, and choline cations are disclosed. Non-patent documents 8 and 9 disclose salts of dimethyl phosphate anions and choline cations, dicationic and cyclic quaternary ammonium cations.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2014-505586

[0006] Patent Document 2: Japanese Patent Application Publication No. 2017-221940

[0007] Patent Document 3: Japanese Patent Application Publication No. 2017-154076

[0008] Patent Document 4: Japanese Patent Application Publication No. 2016-052614

[0009] Non-patent literature

[0010] Non-patent document 1: L. Mei, YJ Dai, A technical review on use of liquid-desiccant dehumidification for air-conditioning application, Renewable and Sustainable Energy Reviews, 2008, 12, 662-689.

[0011] Paper 2:RPSingh,VKMishra,RKDas,Desiccant materials for air conditioning applications:A review,lop Conference Series.Materials Scienceand Engineering,404(2018),012005.

[0012] Interactions of Ionic Liquids andWater,J.Phy.Chem.B 114(2010)10496-10501.

[0013] Reactors 4: L. Jing, Z. Danxing, F. Lihua, W. Xianghong, D. Li, Vapor PressureMeasurement of the Ternary Systems H20+LiBr+[Dmim]Cl,H20+LiBr+[Dmim]BF4,H20+LiCl+[Dmim]Cl,and H20+LiCl+[Dmim]BF4,J.Chem.Eng.Data 56(2011)97-101.

[0014] Raw material 5:Y.Luo,S.Shao,H.Xu,C.Tian,Dehumidification performance of[EMIM]BF4,Appl.Thermal Eng.31(2011)2772-2777.

[0015] Materials 6:Y.Luo,S.Shao,F.Qin,C.Tian,H.Yang,Investigation onfeasibility of ionic liquids used in solar liquid desiccant air conditioningsystem,Solar Energy 86(2012)2718-2724.

[0016] Non-patent literature 7: Watanabe, H.; Komura, T.; Matsumoto, R.; Ito, K.; Nakayama, H.; Nokami, T.; Itoh, T. Design of Ionic Liquids as Liquid Desiccant for an AirConditioning System, Green Energy & Environment, 4 (2019), 139-145.

[0017] Non-patent literature 8: Maekawa, S.; Matsumoto, R.; Ito, K.; Nokami, T.; Li, JX.; Nakayama, H.; Itoh, T.

[0018] Non-patent document 9: Dicationic Type Quaternary Ammonium Salts as Candidates of Desiccants for an Air-Conditioning System, Itoh, T.; Hiramatsu, M.; Kamada, K.; Nokami, T.; Nakayama, H.; Yagi, K.; Yan, F.; Kim, HJ. ACS Sustainable Chem.Eng.,9(2021),14502-14514. Summary of the invention

[0019] Problems to be solved by the invention

[0020] The lithium chloride aqueous solution and calcium chloride aqueous solution disclosed in non-patent documents 1 and 2 have the advantage of being able to stably obtain low-humidity air. However, in general, aqueous solutions of alkali metals and alkaline earth metals of these halide ions are metallically corrosive. Therefore, when these substances are used as humidity-control materials, there is a problem that a material with high corrosion resistance, such as titanium, must be used in the part that contacts the humidity-control material in devices such as air conditioners and absorption refrigerators.

[0021] In addition, the humidity control materials disclosed in Patent Documents 1 to 5 and Non-Patent Documents 4 to 5 use an ionic liquid composed of imidazolium cations and bromide anions and tetrafluoroborate anions as constituent anions. Bromide anions and tetrafluoroborate anions are not only corrosive to metals, but also difficult to handle.

[0022] Patent document 1 reports that the hygroscopicity of the ionic liquid composed of choline cations and lactate anions is high, but the lactate anions are unstable and cannot tolerate long-term use. Non-patent document 3 reports that the hygroscopicity of imidazolium salt ionic liquids mainly depends on the anions, and it is also reported that the water absorption of acetate anions is good. However, only imidazolium cations have been studied as cations, and the aqueous solution of imidazolium ionic liquids has great metal corrosion to copper and the like (non-patent document 7). In addition, it is known that the ionic liquid of acetate anions is unstable and cannot tolerate long-term use (non-patent document 7). In order to solve such problems, in non-patent documents 7 to 9, the anions are selected from dimethylphosphoric acid and methylsulfuric acid. In non-patent document 7, it is clarified that the ionic liquid composed of the combination of phosphonium cations and dimethylphosphoric acid anions shows excellent hygroscopicity. In non-patent document 8, it is reported that the hygroscopicity of the ionic liquid aqueous solution composed of the combination of choline cations and dimethylphosphoric acid anions is large and the metal corrosion is low. In addition, non-patent document 9 reports that quaternary ammonium = dimethyl phosphate, among which dicationic ammonium, shows extremely high hygroscopicity. Although dicationic ammonium = dimethyl phosphate shows hygroscopicity exceeding all humidity-control materials reported in the past, it is known that the viscosity of the aqueous solution of dicationic ammonium = dimethyl phosphate is relatively high (non-patent document 9).

[0023] In particular, as described above, various humidity-controlling materials have been studied, and in recent years, new humidity-controlling materials having excellent hygroscopicity (moisture absorption capacity, water vapor exchange capacity) have been required.

[0024] An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a humidity-controlling material having remarkably excellent hygroscopicity.

[0025] Means for solving problems

[0026] The present inventors have conducted studies based on the above-mentioned problems and have found that the above-mentioned problems can be solved by using a humidity-controlling material including a salt composed of a pyrazolium cation having a specific structure and a phosphate anion.

[0027] Specifically, the above-mentioned problems were solved by the following means.

[0028] <1> A humidity-controlling material comprising a salt composed of a pyrazolium cation represented by the following formula (N1) and a phosphate ester anion.

[0029] [Chemistry 1]

[0030]

[0031] (In formula (N1), R N1 , R N2 , R N3 , R N4 and R N5 Each R is independently a hydrogen atom, or an alkyl group having 1 to 12 carbon atoms which may have a hydroxyl group and may contain one or more oxygen atoms in the chain. N1 , R N2 , R N3 , R N4 and R N5 They may be the same or different. N1 and R N2 At least one of them is an alkyl group having 1 to 12 carbon atoms which may or may not have a hydroxyl group and may or may not contain one or more oxygen atoms in the chain.

[0032] <2> like <1> The humidity-controlling material, wherein the phosphate anion is an anion represented by the following formula (N3).

[0033] [Chemistry 2]

[0034]

[0035] (In formula (N3), R 21 R is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a poly(alkyleneoxy group) having 10 or less carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or a poly(alkylenethio group) having 10 or less carbon atoms. 22 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a poly(alkyleneoxy group) having 10 or less carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or a poly(alkylenethio group) having 10 or less carbon atoms.

[0036] <3> like <1> or <2> The humidity-controlling material is characterized in that the pyrazolium cation (N1) is represented by any one of the following formulae (1) to (4).

[0037] [Chemistry 3]

[0038]

[0039] <4> like <1> ~ <3> The humidity-controlling material according to any one of the preceding claims, wherein the phosphate anion is represented by the following formula (17) or (18).

[0040] [Chemistry 4]

[0041]

[0042] <5> like <1> ~ <4> The humidity-controlling material described in any one of the preceding claims, wherein the viscosity of an aqueous solution of a salt composed of a pyrazolium cation represented by the above formula (N1) and a phosphate anion is 50 mPa·s or less at 25°C.

[0043] <6> like <1> ~ <5> The humidity-controlling material described in any one of the preceding claims, wherein the atmosphere in contact with the aqueous solution of the salt composed of the pyrazolium cation represented by the above formula (N1) and the phosphate anion has an equilibrium water vapor pressure of 100 hPa or less at 25° C. and an equilibrium water vapor pressure of 50 hPa or more at 50° C.

[0044] <7> like <1> ~ <6> The humidity-controlling material according to any one of the preceding claims, wherein the value (ΔVP) represents the difference between the equilibrium water vapor pressure at 50° C. and the equilibrium water vapor pressure at 25° C. of the atmosphere in contact with the aqueous solution of the salt composed of the pyrazolium cation represented by the above formula (N1) and the phosphate anion 50-25 ) is above 40hPa.

[0045] <8> A device comprising <1> ~ <7> The humidity-conditioning material described above.

[0046] Effects of the Invention

[0047] According to the present invention, a humidity-controlling material having high hygroscopicity can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a graph showing the measurement results of the water vapor absorption capacity of the specific salt (8) in Examples.

[0049] Figure 2 (a) is a graph showing the results of a test for measuring the equilibrium water vapor pressure of an 80 mass % aqueous solution of a specific salt (8) in an example, Figure 2 (b) is a graph showing the results of a test for measuring the equilibrium water vapor pressure of an 80 mass % aqueous solution of a specific salt (9) in an example, Figure 2 (c) is a graph showing the results of a test for measuring the equilibrium water vapor pressure of an 80 mass % aqueous solution of a specific salt (10) in Examples.

[0050] Figure 3 It is a graph showing the results of measuring the temperature-variable viscosity of a 70 mass % aqueous solution of specific salts (8), (9), (10) and [DETMC6][DMPO4]2 and 1-butyl-3-methylimidazolium=dimethyl phosphate (Bmim-DMPO4) as a comparative example. DETAILED DESCRIPTION

[0051] Hereinafter, specific embodiments will be described in detail. It should be noted that the following embodiments are examples for describing the present invention, and the present invention is not limited to the embodiments.

[0052] In addition, in this specification, "to" is used to mean that the numerical values ​​described before and after it are included as a lower limit and an upper limit.

[0053] In this specification, various physical property values ​​and characteristic values ​​are values ​​at 23°C unless otherwise specified.

[0054] In the description of the group (atomic group) in this specification, the description of not recording substitution and unsubstituted includes the group (atomic group) without substituent and the group (atomic group) with substituent. For example, "alkyl" not only includes the alkyl without substituent (unsubstituted alkyl), but also includes the alkyl with substituent (substituted alkyl). In this specification, the description of not recording substitution and unsubstituted is preferably unsubstituted.

[0055] When the standards shown in this manual differ in measurement methods etc. depending on the year, unless otherwise specified, they are based on the standards as of January 1, 2022.

[0056] The humidity-controlling material of the present embodiment is characterized in that it contains a salt (hereinafter referred to as a specific salt) composed of a pyrazolium cation represented by the following formula (N1) and a phosphate anion.

[0057] By using the above-mentioned specific salt, a humidity-controlling material having good hygroscopicity (hygroscopicity capacity, water vapor exchange capacity) can be obtained. In addition, the humidity-controlling material of this embodiment can show low viscosity. In addition, the humidity-controlling material of this embodiment can be a humidity-controlling material with low metal corrosion.

[0058] <Pyrazolium cation represented by formula (N1)>

[0059] The humidity-conditioning material of the present invention contains a salt composed of a pyrazolium cation represented by the following formula (N1) and a phosphate anion.

[0060] [Chemistry 5]

[0061]

[0062] (In formula (N1), R N1 , R N2 , R N3 , R N4 and R N5 Each R is independently a hydrogen atom, or an alkyl group having 1 to 12 carbon atoms which may have a hydroxyl group and may contain one or more oxygen atoms in the chain. N1 , RN2 , R N3 , R N4 and R N5 They may be the same or different. N1 and R N2 At least one of them is an alkyl group having 1 to 12 carbon atoms which may or may not have a hydroxyl group and may or may not contain one or more oxygen atoms in the chain.

[0063] In formula (N1), R N1 , R N2 , R N3 , R N4 and R N5 Each independently is a hydrogen atom, or an alkyl group having 1 to 12 carbon atoms, which may or may not have a hydroxyl group and contains or does not contain one or more oxygen atoms in the chain. In the present embodiment, it is preferred that there is no hydroxyl group. The number of carbon atoms of the above-mentioned alkyl group having 1 to 12 carbon atoms is more preferably 1 or more, and can be 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, or 7 or more, and can be 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, or 3 or less. By increasing the number of carbon atoms, there is a tendency for hygroscopicity to be further improved. In addition, by reducing the number of carbon atoms, there is a tendency for viscosity to be further reduced.

[0064] R N1 , R N2 , R N3 , R N4 and R N5 They may be the same or different. One or more R substituted on the nitrogen atom constituting the five-membered ring N1 , R N2 It is an alkyl group having 1 to 12 carbon atoms which may or may not have a hydroxyl group and may or may not contain one or more oxygen atoms in the chain. In addition, the number of oxygen atoms that may be contained in the alkyl group having 1 to 12 carbon atoms is preferably 0 to 8, more preferably 0 to 4, and further preferably 0 to 2. In the present embodiment, it is preferred that the alkyl group having 1 to 12 carbon atoms does not contain an oxygen atom.

[0065] R N1 , R N2 , R N3 , R N4 and R N5 As long as the performance is not significantly deteriorated, it may further have a substituent (e.g., a hydroxyl group, a thiol group (mercapto group), etc.). Alternatively, within the range that the performance is not significantly deteriorated, the carbon atom of the pyrazole parent core may have the above-mentioned substituent, a specific alkyl group, etc. However, in the present embodiment, it is preferred that there is no substituent.

[0066] The R used in this embodiment N1 and RN2 In one example, R N1 and R N2 One of them is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms (preferably 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms, and further preferably 1 carbon atom), and the other is an alkyl group having 1 to 12 carbon atoms (preferably 2 or more carbon atoms, more preferably 3 or more carbon atoms, further preferably 5 or more carbon atoms, further preferably 6 or more carbon atoms, and preferably 11 or less carbon atoms). With such a configuration, the effect of the present invention tends to be more effectively exerted.

[0067] In addition, R used in this embodiment N1 and R N2 In, R N1 The number of carbon atoms in the alkyl group is N2 The difference in the number of carbon atoms of the alkyl groups is preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more. The upper limit is, for example, 10 or less. With such a configuration, the effects of the present invention tend to be more effectively exhibited.

[0068] <Pyrazolium cation represented by formula (1-1)>

[0069] The pyrazolium cation represented by the above formula (N1) is preferably a pyrazolium cation represented by the following formula (1-1).

[0070] [Chemistry 6]

[0071]

[0072] In formula (1-1), R N1 and R N2 It has the same meaning as the above formula (N1).

[0073] The molecular weight of the pyrazolium cation used in the present embodiment is preferably 110 to 500.

[0074] Specific examples (1) to (4) of the pyrazolium cation used in the present embodiment are shown below, but the present invention is not limited to these examples as a matter of course.

[0075] [Chemistry 7]

[0076]

[0077] <Phosphate anion>

[0078] The type of the phosphate anion used in the present embodiment is not particularly limited as long as it can form a salt with a specific pyrazolium cation, but the phosphate anion represented by the formula (N3) is preferred.

[0079] By using such a phosphate anion, a stable salt can be formed with the pyrazolium cation represented by formula (N1), effectively suppressing the generation of odor. It should be noted that in the present invention, the term phosphate anion refers to anions of phosphonic acid (phosphite) esters or anions of phosphinate (phosphite) esters in addition to anions of phosphate esters.

[0080] [Chemistry 8]

[0081]

[0082] In formula (N3), R 21 It is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms (preferably 1 to 3), a hydroxyalkyl group having 1 to 6 carbon atoms (preferably 1 to 3), an alkoxy group having 1 to 6 carbon atoms (preferably 1 to 3), an alkenyl group having 2 to 6 carbon atoms (preferably 2 to 3), a poly(alkyleneoxy group) having 10 or less carbon atoms (preferably 3 to 8), an alkylthio group having 1 to 6 carbon atoms (preferably 1 to 3), or a poly(alkylenethio group) having 10 or less carbon atoms (preferably 3 to 8).

[0083] R 22 It is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms (preferably 1 to 3), an alkoxy group having 1 to 6 carbon atoms (preferably 1 to 3), an alkenyl group having 2 to 6 carbon atoms (preferably 2 to 3), a poly(alkyleneoxy) group having 10 or less carbon atoms (preferably 3 to 8), an alkylthio group having 1 to 6 carbon atoms (preferably 1 to 3), or a poly(alkylenethio) group having 10 or less carbon atoms (preferably 3 to 8).

[0084] Among them, R 21 and R 22 Preferred are alkyl groups having 1 to 6 carbon atoms (preferably 1 to 3) and alkoxy groups having 1 to 6 carbon atoms (preferably 1 to 3), more preferred are alkoxy groups having 1 to 6 carbon atoms (preferably 1 to 3), further preferred are alkoxy groups having 1 to 3 carbon atoms, and still more preferred are methoxy and ethoxy groups.

[0085] The molecular weight of the phosphoric acid ester used in the present embodiment is preferably 64 to 650.

[0086] Specific examples of the phosphate anion used in the present embodiment are shown below, but of course the phosphate anion in the present embodiment is not limited to these examples.

[0087] [Chemistry 9]

[0088]

[0089] [Chemistry 10]

[0090]

[0091] <Pyrazolium cation salt>

[0092] Specific examples of the pyrazolium alkyl phosphate as the specific salt are represented by the following formula (N4), and more specifically, salts represented by the following formulas (7), (8), (9) and (10) are preferred.

[0093] [Chemistry 11]

[0094]

[0095] R in formula (N4) N1 ~R N5 The meanings of the groups in formula (N1) are the same as those in formula (N4). 21 and R 22 It is a group having the same meaning as the group in formula (N3).

[0096] For example, typical examples of the salt composed of the pyrazolium cation represented by the above formula (1-1) and the dimethyl phosphate anion are the following chemical formulas (7) to (10).

[0097] [Chemistry 12]

[0098]

[0099] By making R N1 , R N2 Any of the alkoxy trialkyl phosphates in the formula (N1) acts on the pyrazolium cation except that R is omitted. N1 , R N2 The specific salt can be synthesized by oniumization of any of the pyrazole structures in the above-mentioned. The synthesis process is easy to react, so the specific salt can be synthesized extremely simply. In addition, since a metal exchange reaction and anion exchange using an ion exchange resin are not required, the mixing of halogens that cause corrosion can be suppressed.

[0100] It should be noted that the specific salt may be solid or liquid at room temperature (so-called room-temperature molten salt (ionic liquid)).

[0101] <Humidity Control Materials>

[0102] The humidity-controlling material may contain one specific salt, or may contain two or more specific salts in which one or both of the above-mentioned cation and the above-mentioned anion are different.

[0103] The humidity-controlling material may further contain other components generally used in humidity-controlling materials within a range that does not inhibit the effects of the present embodiment.

[0104] The humidity control material may be an aqueous solution. In this case, the specific salt is contained in the form of the above-mentioned cation and the above-mentioned anion.

[0105] The humidity control material of this embodiment can be applied to, for example, a dehumidification air conditioner or an absorption refrigerator. It should be noted that the humidity control material of this embodiment can be used in either an open system or a closed system. When used in an open system, the humidity control material whose anions constituting the specific salt are the above-mentioned phosphate anions is particularly suitable from the aspect of suppressing odor.

[0106] In another embodiment, the salt is preferably an ionic liquid. An ionic liquid is a substance having a melting point of 100° C. or less at 1 atmosphere. In particular, the humidity-controlling material of this embodiment is preferably a liquid at least in the range of 0 to 5° C.

[0107] As described above, the humidity control material of the present embodiment can be an aqueous solution, preferably an aqueous solution. In this case, as described above, the specific salt is contained in the state of the above-mentioned cation and the above-mentioned anion. The amount of water is preferably 10% by mass or more, more preferably 15% by mass or more relative to the total amount of the above-mentioned salt (ionic liquid) and water. In addition, the amount of water is preferably 95% by mass or less, more preferably 80% by mass or less, and particularly preferably 60% by mass or less.

[0108] Furthermore, the humidity-controlling material of the present embodiment may further contain other components generally used in humidity-controlling materials within a range not impairing the effects of the present invention.

[0109] The humidity control material of this embodiment can be used in devices such as air conditioners and absorption refrigerators. As examples of such devices, reference can be made to the records of Japanese Patent Publication No. 2006-142121, Japanese Patent Publication No. 2018-144029, Japanese Patent Publication No. 2020-30004, etc. In particular, since the generation of odor can be suppressed, it is particularly suitable for use in open systems such as dehumidifying air conditioners.

[0110] The humidity-controlling material of this embodiment can be preferably applied to, for example, a dehumidifying air conditioner or an absorption refrigerator. It should be noted that the humidity-controlling material of this embodiment can be used in either an open system or a closed system. When used in an open system, the humidity-controlling material whose anions constituting the specific salt are the above-mentioned phosphate anions is particularly suitable from the aspect of suppressing odor.

[0111] The pyrazolium phosphate solution constituting the humidity control material of the present embodiment is preferably low in viscosity. In terms of viscosity at 25°C, the viscosity of its aqueous solution (e.g., a 70% by mass aqueous solution) is preferably 50 mPa·s or less, more preferably 40 mPa·s or less, further preferably 30 mPa·s or less, further preferably 25 mPa·s or less, and further preferably 20 mPa·s or less. By making the viscosity of the pyrazolium phosphate low, it is expected that the transport efficiency of the humidity control material aqueous solution will be improved, and the water vapor exchange efficiency brought about by contact with the external air will be improved. The lower limit is, for example, 5 mPa·s or more at 25°C.

[0112] The difference between the viscosity at 20°C and the viscosity at 50°C of the aqueous solution of the present embodiment (e.g., 70% by mass aqueous solution) is preferably 40 mPa·s or less, more preferably 20 mPa·s or less. The difference between the viscosity at 20°C and 50°C can be reduced by shortening the chain of the alkyl group of the pyrazolium cation.

[0113] The lower limit of the viscosity difference is preferably more than 0 mPa·s.

[0114] The humidity control material of this embodiment is a humidity control material with low corrosion to various metals such as zinc, copper, aluminum, stainless steel, etc. In this embodiment, since a pyrazolium salt is used, the acidity of hydrogen at the position sandwiched by N does not increase, and there is a tendency to be able to more effectively suppress metal corrosion.

[0115] According to the above configuration, a humidity-controlling material having a high moisture absorption rate can be obtained. In addition, since the generation of odor can be suppressed, it is particularly suitable for use in an open system such as a dehumidifying air conditioner.

[0116] Example

[0117] The present invention is described in more detail below by giving examples. The materials, usage, ratio, processing content, processing sequence, etc. shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. In addition, Et in the structural formula shown below is an ethyl group, and Me is a methyl group.

[0118] When the measuring equipment used in the examples is difficult to obtain due to discontinuation of production or the like, other equipment having equivalent performance may be used for the measurement.

[0119] Unless otherwise specified, the present examples were conducted under an environment of 23° C. and a relative humidity of 40%.

[0120] <Synthesis of Specific Pyrazolium Salt>

[0121] Example 1: Synthesis of 1-ethyl-2-methylpyrazolium dimethyl phosphate (8)

[0122] [Chemistry 13]

[0123]

[0124] Sodium hydride (NaH) (12.4 g, ca. 60% in mineral oil, 310 mmol) was weighed in a 500 mL three-necked eggplant flask equipped with a serpentine condenser and a 100 mL cylindrical dropping funnel. After argon replacement, dry hexane was added at room temperature, and the supernatant was removed (twice) to remove the mineral oil component. Next, 100 mL of dry tetrahydrofuran (THF) was added at room temperature to prepare a suspension. The flask was immersed in an ice bath, and a solution of pyrazole (21) (20.42 g, 300 mL) in dry THF (100 mL) was added dropwise at 0°C. At this time, since hydrogen gas was generated, the solution was added dropwise over 1 hour while releasing the generated hydrogen gas to generate the sodium salt (23). After the addition was completed, the mixture was stirred at room temperature for 1 hour, and then a solution of iodoethane (51.47 g, 330 mmol) in dry THF (100 mL) was added dropwise over 30 minutes at room temperature. After the addition was completed, the mixture was refluxed at 70°C for 19 hours. After natural cooling, 5.58 g (310 mmol) of borneol was added at 0°C, and the mixture was stirred at room temperature for 30 minutes. The precipitated sodium iodide was removed by diatomaceous earth filtration, and the contents were transferred to a 500 mL single-necked eggplant flask, and concentrated under reduced pressure using a rotary evaporator. After THF as a solvent was roughly distilled off, a vigreux tube was installed, and Claisen distillation was performed under reduced pressure to obtain 1-ethylpyrazole (24) (bp 72-75°C / 22 hPa, 21.17 g, 220 mmol) with a yield of 73%.

[0125] 1 H NMR (500MHz, ppm, CDCl3) δ1.47(3H,t,J=7.2Hz), 4.17(2H,q,J=7.2Hz), 6.22(1H,t,J=2.4Hz), 7.37(1H,d,J=4.0Hz), 7.48(1H,d,J=2.4Hz); 13 C NMR (20MHz, ppm, CDCl3) δ15.6, 45.8, 105.2, 128.1, 139.0ppm.

[0126] 1-Ethylpyrazole (24) (20.60 g, 214 mmol) was weighed into a 200 mL two-necked eggplant flask equipped with a serpentine condenser, trimethyl phosphate (33.1 g, 236 mmol) was added from a side tube at room temperature, and the reaction system was replaced with argon after flash evaporation, and stirred at 120°C for 72 hours. After cooling naturally to room temperature, 100 mL of pure water was added to prepare an aqueous solution, and the aqueous layer was washed with ether three times, freeze-dried, and then dried at 50°C and 7.1 hPa for 7 hours. As a result, pyrazolium salt (8) (49.29 g, 209 mmol) was obtained as a semi-molten colorless oil with a yield of 97%.

[0127] 1 H NMR (500MHz, ppm, CDCl3) δ1.60 (3H, t, J = 7.2Hz), 3.56 (3H, s), 3.71 (3H, s), 4.42 (2H, q, J = 7.2Hz), 6.80 (1H, t, J = 2.4Hz), 8.16 (2H, t, J = 3.2Hz); 13 C NMR((20MHz,ppm,CDCl3)δ13.1,36.5,45.3,53.0,53.2,107.3,137.1,139.6ppm.HRMS(ESI)C6H 11 N2 + 111.09227; found 111.0922; HRMS(ESI)calcd for C2H6O4P - 125.000382; found 124.9995.

[0128] The structures and chemical formula numbers of pyrazolium salts as specific salts synthesized by the same method are represented by the above-mentioned specific salts (9) and (10).

[0129] Example 2: Synthesis of 1-methylpyrazolium dimethyl phosphate (7)

[0130] [Chemistry 14]

[0131]

[0132] Trimethyl phosphate (1.54 g, 11 mmol) was added to pyrazole (21) (0.68 g, 10.0 mmol) at room temperature, and the mixture was reacted at 85°C for 24 hours in an argon atmosphere, and then naturally cooled to room temperature. The residue was washed with hexane and diethyl ether, and then dried under reduced pressure at 55°C (8.5 hPa) for 3 hours using a rotary evaporator and then a vacuum pump to obtain a specific salt (7) in the form of a colorless oil with a yield of 81% (1.69 g, 8.12 mmol). The aqueous solution of the specific salt (7) showed acidity (pH 3.4), so only the hygroscopicity was investigated. It should be noted that even if more than 2 equivalents of trimethyl phosphate were added, no dimethylpyrazolium salt was generated.

[0133] 1 H NMR (80MHz, ppm, CDCl3) δ3.57(3H,s),3.76(3H,s),4.33(3H,s),6.73(1H,t,J=3.2Hz),8.47(1H,d,J=2.4Hz),10.55(2H,s); 13 C NMR ((20MHz,ppm,CDCl3)δ37.0,53.1,53.3,107.3,138.3ppm.

[0134] <Moisture absorption test, Example 3>

[0135] A petri dish into which 1.0038 g of the specific salt (8) of Example 1 was dispensed was placed together with a hygrometer (illumination, ultraviolet, temperature, and humidity data logger TR-74Ui manufactured by T&D Co., Ltd.) in a zippered container with a volume of 1110 cm 2 The sample was placed in a plastic bag (Ziploc (registered trademark), 273 mm × 268 mm, manufactured by Asahi Kasei Household Products Co., Ltd.) and sealed. The bag was placed in a 30°C constant temperature chamber and the humidity change in the plastic bag was measured until the humidity in the plastic bag reached an equilibrium state. The results are shown in Figure 1 .like Figure 1 As shown, it can be seen that the humidity decreases with the passage of time, and the specific salt (8) has hygroscopicity.

[0136] In the same manner, 1.000 g of the specific salts (7), (9) and (10) after vacuum drying were placed in a petri dish and subjected to the same moisture absorption test as that of the specific salt (8).

[0137] Comparison of the hygroscopic performance of [DETMC6][DMPO4]2, which has the highest hygroscopic performance ever, as described in Non-Patent Document 9, and calcium chloride currently used in dehumidifiers [Table 1]

[0138]

[0139] Compared with Comparative Example 4-1 using calcium chloride for drying and Comparative Example 4-2 using silica gel for drying shown in Table 1, which are currently widely used as desiccants, specific salts (7) to (10) showed exceptionally high hygroscopicity. In addition, compared with Bmim-DMPO4 (Comparative Example 4-4) which is a general ionic liquid, specific salts (7) with the lowest hygroscopicity among the specific salts synthesized this time showed 1.5 times (DC (mol) per mole) compared with Bmim-DMPO4, and specific salt (10) with the highest hygroscopicity among the monocationic pyrazolium salts showed 3.5 times (DC (mol) in terms of molar ratio. The hygroscopicity per mole of specific salts (7) to (10) was in the order of (10) > (9) > (8) > (7), and the hygroscopicity per gram was in the order of (10) > (9) > (8) > (7).

[0140] [DETMC6][DEPO4]2 was the world's highest level of hygroscopic compound at the time the paper was published, and it is believed that the hygroscopic performance of the specific salt (10) exceeds that of all previously reported humidity-control materials.

[0141] Although it is reported that the hygroscopicity of an ionic liquid is high when the cationic part is small (Non-Patent Document 3), it is found that the specific salts (7) to (10) as pyrazolium salt ionic liquids cannot be predicted based on this rule.

[0142] <Equilibrium Vapor Pressure Measurement, Example 4>

[0143] 80 mass % aqueous solutions of the specific salts (8), (9) and (10) synthesized in Example 1 were prepared, and the equilibrium water vapor pressure at each temperature from 20°C to 60°C was measured. The results are shown in Figure 2 .

[0144] In the same manner, specific salts (8), (9), (10), 80 mass % aqueous solutions of [DETMC6][DEPO4]2, and 30 mass % aqueous solutions of lithium chloride were prepared, and their equilibrium water vapor pressures were measured at 25°C and 50°C. The equilibrium water vapor pressures are shown in Table 2.

[0145] Equilibrium water vapor pressures of specific salts (8) to (10), [DETMC6] [DEPO4] 2 and lithium chloride at 25°C and 50°C [Table 2]

[0146]

[0147] As shown in Examples 5-1 to 5-3 of Table 2, it can be seen that the equilibrium water vapor pressure of 80 mass % aqueous solutions of specific salts (8) to (10) shows very low values ​​of 19 hPa or 21 hPa at 25°C, which is slightly lower than the 30 mass % lithium chloride aqueous solution shown in Comparative Example 5-2 of Table 2.

[0148] The humidity-control material used in liquid dehumidification air conditioners needs to smoothly absorb and release water vapor between the contacting external air. Therefore, it is preferred that the equilibrium water vapor pressure is low at low temperatures and high at high temperatures. From this aspect, the equilibrium water vapor pressure at 25°C is preferably below 100 hPa, more preferably below 70 hPa, further preferably below 50 hPa, and further preferably below 20 hPa. The lower limit is not particularly limited, but is actually above 5 hPa. The equilibrium water vapor pressure at 50°C is preferably above 50 hPa, more preferably above 80 hPa, and particularly preferably above 100 hPa. The upper limit is not particularly limited, but is actually below 800 hPa.

[0149] The value (ΔVP) represents the difference between the equilibrium water vapor pressure at 50°C and the equilibrium water vapor pressure at 25°C. 50-25 ) is preferably 20 hPa or more, more preferably 30 hPa or more, further preferably 40 hPa or more, further preferably 75 hPa or more, and further preferably 100 hPa or more. There is no particular upper limit, but the actual ΔVP 50-25 Below 200hPa.

[0150] The results shown in Example 5-1 of Table 2 show that the function of the specific salt (8) as a humidity control material is equivalent to that of a 30 mass % lithium chloride aqueous solution in the case of an 80 mass % aqueous solution, indicating that water vapor exchange can be smoothly performed through contact with external air.

[0151] The experimental results shown in Examples 5-2 and 5-3 of Table 2 show that the 80 mass % aqueous solution of the specific salt (9) and the specific salt (10) function as a humidity control material better than the 30 mass % lithium chloride aqueous solution at low temperatures. However, it is known that the equilibrium water vapor pressure at 50°C is also low, and the equilibrium water vapor pressure is low compared to the 30 mass % lithium chloride aqueous solution in terms of water vapor exchange caused by contact with the external air, and the water vapor exchange performance is low.

[0152] <Viscosity Test, Example 5>

[0153] The humidity control material used in liquid dehumidification air conditioners is expected to have as low viscosity as possible. Figure 3 As shown, the viscosity of the specific salt of the present invention is low. Figure 3Among them, [DETMC6][DMPO4]2, specific salt (10), specific salt (9), specific salt (8), and Bmim-DMPO4 are shown in the order of high viscosity (Viscosity) at a temperature (Temp.) of 20°C.

[0154] like Figure 3 As shown, it can be seen that among the 70 mass % aqueous solutions of specific salts (8) to (10), the viscosity of specific salt (10) is high, but the hygroscopic performance of Bmim-DMPO4 is low (Comparative Example 4-4 in [Table 1]), which is only about 40% of that of specific salt (8) in terms of molar ratio. In addition, it can be seen that at any temperature, the viscosity of the 70 mass % aqueous solutions of specific salts (8) to (10) is much lower than that of the 70 mass % aqueous solution of [DETMC6][DMPO4] (Comparative Example 4-3 in [Table 1]) as a comparative example. In a liquid dehumidification air conditioner, the humidity of the external air and the air conditioning temperature are controlled by contacting the external air with the humidity control material aqueous solution. Therefore, in order to reduce the resistance in the piping of the humidity control material aqueous solution and improve the contact efficiency with the external air, the viscosity of the humidity control material aqueous solution is preferably low. The 70 mass % aqueous solutions of specific salts (8) to (10) have low viscosities at various temperatures and can effectively control the humidity by contacting with the external air.

[0155] In addition, the viscosity is measured in accordance with ISO 23581:2020.

Claims

1. A humidity-controlling material comprising a salt composed of a pyrazolium cation and a phosphate anion represented by the following formula (N1), [Chemistry 1] In formula (N1), R N1 , R N2 , R N3 , R N4 and R N5 Each independently represents a hydrogen atom, or an alkyl group having 1 to 12 carbon atoms which may have a hydroxyl group and may contain one or more oxygen atoms in the chain; R N1 , R N2 , R N3 , R N4 and R N5 They may be the same or different from each other; R substituted on the nitrogen atom constituting the five-membered ring N1 and R N2 At least one of the groups is an alkyl group having 1 to 12 carbon atoms which may have a hydroxyl group and may contain one or more oxygen atoms in the chain.

2. The humidity-controlling material according to claim 1, wherein The phosphate anion is an anion represented by the following formula (N3), [Chemistry 2] In formula (N3), R 21 is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a poly(alkyleneoxy group) having 10 or less carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or a poly(alkylenethio group) having 10 or less carbon atoms; R 22 It is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a poly(alkyleneoxy group) having 10 or less carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or a poly(alkylenethio group) having 10 or less carbon atoms.

3. The humidity-controlling material according to claim 1 or 2, wherein The pyrazolium cation (N1) is represented by any one of the following formulae (1) to (4), [Chemistry 3] 4. The humidity-controlling material according to any one of claims 1 to 3, wherein The phosphate anion is represented by the following formula (17) or (18), [Chemistry 4] 5. The humidity-controlling material according to any one of claims 1 to 4, wherein The viscosity of an aqueous solution of a salt composed of a pyrazolium cation represented by the formula (N1) and a phosphate anion is 50 mPa·s or less at 25°C.

6. The humidity-controlling material according to any one of claims 1 to 5, wherein The atmosphere in contact with the aqueous solution of the salt composed of the pyrazolium cation represented by the formula (N1) and the phosphate anion has an equilibrium water vapor pressure of 100 hPa or less at 25°C and an equilibrium water vapor pressure of 50 hPa or more at 50°C.

7. The humidity-controlling material according to any one of claims 1 to 6, wherein The difference between the equilibrium water vapor pressure at 50°C and the equilibrium water vapor pressure at 25°C of the atmosphere in contact with the aqueous solution of the salt composed of the pyrazolium cation represented by the formula (N1) and the phosphate anion, ΔVP, is represented by 50-25 Above 40hPa. 8 . A device comprising the humidity-controlling material according to claim 1 .

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