Compound, latent heat storage material, latent heat storage body, electronic device, and power storage device

Abstract

To provide a compound having latent heat storage properties, a latent heat storage material, a latent heat storage body, an electronic device, and a power storage device.SOLUTION: The invention provides a compound represented by the formula (I) in the figure, and applications thereof. In formula (I), if n=m, then n is an integer from 1 to 30, and l represents an odd number less than 10; if n≠m, then n and m are each independently selected, with n being an integer from 0 to 30, m being an integer from 1 to 30, and l being an integer from 1 to 10.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a compound, a latent heat storage material, a latent heat storage body, an electronic device, and an electricity storage device. [Background technology]

[0002] In recent years, digital home appliances have become increasingly popular, and electronic devices that handle large amounts of information at high speeds are generating ever-increasing amounts of heat. In addition, as devices become smaller, lighter, and thinner, the importance of heat countermeasures, such as how to efficiently dissipate heat from components, is growing. In particular, mobile devices such as smartphones and tablet PCs (personal computers) are becoming more sophisticated and high-performance despite their small size, and the heat density is increasing significantly. In mobile devices, the increased heat density increases the risk of thermal runaway and accelerated fatigue due to thermal cycles of solder, and heat countermeasures are therefore required to improve reliability.

[0003] Passive cooling methods using phase change materials (PCMs) have been attracting attention as a cooling method for electronic devices. PCMs are also known as latent heat storage materials, and because they can absorb heat with almost no change in temperature due to their latent heat, the use of PCMs can provide a delay effect, which is the time it takes for the temperature to rise. Latent heat storage materials utilize the heat absorption and release that occurs when a substance changes state, and have the advantage that they can be used repeatedly and have a larger heat storage capacity than other heat storage materials. Examples of latent heat storage materials include paraffin [melting point: 36.4°C (eicosane: C 20 H 42), sodium acetate trihydrate (melting point: 58°C), erythritol (melting point: 119°C), and other compounds are known. Paraffins have a relatively high latent heat but are flammable, hydrates have poor recyclability, and erythritol has a high phase change temperature, among other drawbacks. In addition, 1-hexadecyl-3-methylimidazolium chloride, an imidazole-based ionic liquid, is known as a latent heat storage material (see, for example, Non-Patent Documents 1 and 2). All of these compounds are latent heat storage materials that utilize the latent heat of fusion that accompanies the phase change from solid to liquid. In addition, it is known that dicarboxylic acids with a short carbon number have a large amount of latent heat during phase change (see FIG. 1 and Non-Patent Document 3), but their phase change temperature is as high as 150°C or more, and they cannot be used for electronic device applications. However, it has been reported that diesterified dicarboxylic acids can lower their phase change temperature. (Non-Patent Documents 4 and 5) For example, Non-Patent Document 4 reports that a diester compound of tetradecanol with a dicarboxylic acid having 10-14 carbon atoms has a melting point of 50-58°C and a latent heat of 200 J / g or more. In addition, Non-Patent Document 5 reports that the melting points of succinic acid ditetradecyl ester (carbon number 14) and dioctadecyl ester (carbon number 18), which are dicarboxylic acids with 4 carbon atoms, are 47 and 64°C, respectively, and the latent heat at that time is 195 and 202 J / g, respectively. It has also been reported that the hysteresis during melting / solidification is small at 7°C or less, and that the repeatability is excellent. However, as is clear from the example of succinic acid, and this is a general tendency, as the number of carbon atoms in the alkyl group of the ester portion increases, the latent heat amount increases but the melting point also becomes higher, which is not desirable for application as a latent heat material for electronic components.

[0004] In recent years, electric vehicles equipped with high-performance batteries have become widespread in order to utilize energy more efficiently. As high-performance batteries to be installed in electric vehicles, lithium-ion batteries in particular have been actively developed, and efforts are being made to increase the output and capacity of lithium-ion batteries. However, excessively high temperatures due to high output and the large amount of heat generated during charging and discharging due to high capacity can significantly reduce the battery's lifespan, and in the worst case, there is a risk of fire and explosion. In general, lithium-ion batteries tend to show significant performance degradation in a usage temperature range exceeding 60°C (see, for example, Non-Patent Document 6). For this reason, a thermal management technology that maintains the temperature of the battery in an optimal temperature range (for example, 15°C to 60°C) is essential for optimizing battery characteristics, extending the battery's lifespan, and improving the safety of the battery, and therefore a further increase in the amount of latent heat is desired. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] E.Thomas, D.Thomas, S.Bhuvaneswari, KPVijayalakshmi, BKGeorge, “1-Hexadecyl-3-methylimidazolium chloride:Structure, thermal stability and decomposition mechanism”, J.Mol.Liq., vol.249(2018), pp.404-411. [Non-Patent Document 2] M. Bendova, M. Canji, MG Bogdanov, Z. Wagner, N. Zdolsek, F. Quirion, “Phase Transitions in Higher-Melting Ionic Liquids: Thermal Storage Materials or Liquid Crystals?” Chemical Engineering Transactions Vol.69,pp.37-42(2018)ISBN 978-88-95608-66-2(The penultimate “a” in the author’s name “M. Bendova” is an “a” with a charka, the “C” in “M. Canji” is an “C” with a charka, and the “s” in “N. Zdolsek” is an “s” with a charka.) [Non-Patent Document 3] NIST Chemistry WebBook,SRD 69 NIST Chemistry WebBook [Non-Patent Document 4] Ahmet Alper Aydin, “Diesters of high-chain dicarboxylic acids with 1-tetradecanol as novel organic phase change materials for thermal energy storage”Solar Energy Materials & Solar Cells Vol.104(2012)pp.102-108 [Non-Patent Document 5] Derya Kahraman Doguscu, “Synthesis and characterization of ditetradecyl succinate and dioctadecyl succinate as novel phase change materials for thermal energy storage” Solar Energy Materials & Solar Cells Vol.200(2019)110006 [Non-Patent Document 6] LMThompson, JEHarlow, A.Eldesoky, MKGBauer, JHCheng, WSStone, T.Taskovic, CRMMcFarlane and JRDahn, “Study of Electrolyte and Electrode Composition Changes vs Time in Aged Li-Ion Cells” J.Electrochem.Soc.Vol.168(2021)020532 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, latent heat storage materials used for cooling electronic devices are required to have a low phase change temperature and a large amount of latent heat. In addition, latent heat storage materials are required to have the property of absorbing heat due to a phase change and generating heat when cooled after the phase change, and then returning to the state before the phase change (so-called repeatability). In other words, if there is no heat generation after the phase change, the material cannot return to the state before the phase change.

[0007] The present disclosure has been made in consideration of the above circumstances. An object of one embodiment of the present disclosure is to provide a novel compound having latent heat storage properties. The problem to be solved by another embodiment of the present disclosure is to provide a latent heat storage material having excellent latent heat storage properties, preferably a latent heat storage material having a low phase change temperature of 78°C or less, a large amount of latent heat, and repeatability properties. Another problem to be solved by another embodiment of the present disclosure is to provide a latent heat storage body including the latent heat storage material, and an electronic device and an electricity storage device including the latent heat storage material. [Means for solving the problem]

[0008] In the course of repeated investigations to solve the above problems, the present inventors focused on dicarboxylic acids that have a large amount of latent heat during phase change. Then, after extensive research on dicarboxylic acid diester compounds with reference to Non-Patent Document 5, they found that there is an optimal value for the number of carbon atoms of dicarboxylic acid in dicarboxylic acid diester compounds. They also found that by making an asymmetric diester compound by changing the number of carbon atoms in the ester moiety, it is possible to have a high amount of latent heat and to lower the phase change temperature, in this case the melting point, and thus completed the present disclosure.

[0009] Specific means for solving the above problems include the following aspects. <1> A compound represented by the following formula (I):

[0010] [ka]

[0011] In the formula (I), when n=m, n is an integer of 1 to 30, and l is an odd number less than 10. When n≠m, n and m are each independently an integer of 0 to 30, m is an integer of 10 to 30, and l is an integer of 1 to 10. <2> <1> A latent heat storage material comprising the compound according to claim 1. <3> Used in electronic devices or power storage devices <2> The latent heat storage material according to claim 1. <4> <2> A latent heat storage medium comprising the latent heat storage material according to claim 1. <5> <2> An electronic device comprising the latent heat storage material according to claim 1. <6> <2> An electricity storage device comprising the latent heat storage material according to claim 1. Effect of the Invention

[0012] According to one embodiment of the present disclosure, a novel compound having latent heat storage properties is provided. According to another embodiment of the present disclosure, there is provided a latent heat storage material that utilizes latent heat associated with a phase change, preferably having a low phase change temperature of 78°C or less, a large amount of latent heat, and repeatability characteristics. According to another embodiment of the present disclosure, there is provided a latent heat storage body including the latent heat storage material, and an electronic device and an electricity storage device including the latent heat storage material. [Brief description of the drawings]

[0013] [Figure 1] 1 is a graph showing the relationship between the number of carbon atoms 1 of the alkylene chain of a dicarboxylic acid, the latent heat, and the melting point. [Diagram 2] 1 is a graph showing the relationship between the latent heat and the melting point of dicarboxylic acid didodecyl esters having different carbon numbers 1 in Tables 1 and 2. [Diagram 3] 1 is a graph showing the relationship between the latent heat and the melting point of dioctadecyl dicarboxylates having different carbon numbers 1 in Tables 1 and 2. [Figure 4] 1 is a graph showing the relationship between the latent heat and the melting point of succinic acid diesters having different carbon numbers in the ester moiety of the dicarboxylate diester. [Diagram 5] 1 is a graph showing the relationship between the latent heat and the melting point of glutaric acid diesters having different numbers of carbon atoms in the ester moiety of dicarboxylate diesters. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The compound of the present disclosure, the latent heat storage material containing the compound, the latent heat storage body containing the latent heat storage material, and the electronic device and the power storage device containing the latent heat storage material will be described in detail below. The explanation of the requirements described below may be based on the representative embodiment of the present disclosure, but the present disclosure is not limited to such an embodiment, and can be implemented by making appropriate changes within the scope of the purpose of the present disclosure.

[0015] In the present disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the lower limit and upper limit, respectively. In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in the present disclosure. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0016] [Compound] The compound of the present disclosure is a compound represented by the following formula (I):

[0017] [ka]

[0018] In the formula (I), when n≠m, n and m each independently represent an integer of 0 to 30, m an integer of 1 to 30, and l an integer of 1 to 10. Preferably, n and m are each independently an integer of 0 to 24, m an integer of 10 to 24, and l an integer of 1 to 4. In the formula (I), when n=m, n is an integer of 1 to 30, and l is an odd number less than 10. Preferably, n is an integer of 10 to 24, and l is an odd number of 1 to 5.

[0019] The compound represented by the above formula (I) has latent heat storage properties. In the present disclosure, "latent heat storage properties" preferably means satisfying the properties of a phase change temperature of 78°C or lower and a latent heat amount of 120 J / g or more, and having repeatability.

[0020] [Method of synthesizing the compound represented by formula (I)] The method for synthesizing the compound represented by formula (I) is not particularly limited. Specifically, the compound represented by formula (I) can be synthesized by the method described in the Examples.

[0021] [Latent heat storage material] The latent heat storage material of the present disclosure contains the compound represented by the above-mentioned formula (I). Hereinafter, the latent heat storage material of the present disclosure containing the compound represented by formula (I) will be described. The latent heat storage material disclosed herein is a latent heat storage material that utilizes latent heat associated with a phase change, contains a compound represented by formula (I) described above, has a low phase change temperature of 78°C or less, a large amount of latent heat, and has repeatability.

[0022] The present inventors have found that, in the dicarboxylate diester represented by formula (I), by varying the number of carbon atoms in the ester moiety, it is possible to lower the phase change temperature while maintaining a high latent heat quantity. In addition, it has been found that, in the dicarboxylate diester compound, when the number of carbon atoms in the ester compound is the same, the optimum value of the latent heat quantity exists when the number of carbon atoms in the alkylene chain of the dicarboxylate is an odd number.

[0023] The latent heat storage material of the present disclosure preferably contains a compound represented by the following formula (I).

[0024] [ka]

[0025] In the formula (I), when n ≠ m, n and m each independently represent an integer of 0 to 30, m an integer of 1 to 30, and l an integer of 1 to 10. <1> The compound according to claim 1, Preferably, n and m are each independently an integer of 0 to 24, m an integer of 10 to 24, and l an integer of 1 to 4. In the formula (I), when n=m, n is an integer of 1 to 30, and 1 is an odd number less than 10. <1> Preferably, n is an integer of 10 to 24, and 1 is an odd number of 1 to 5.

[0026] The latent heat storage material of the present disclosure may contain only one type of compound represented by formula (I), or may contain two or more types.

[0027] The content of the compound represented by formula (I) in the latent heat storage material of the present disclosure is not particularly limited, but for example, it is preferably 10% by mass to 100% by mass, more preferably 30% by mass to 100% by mass, and even more preferably 50% by mass to 100% by mass, relative to the total solid content in the latent heat storage material. In the present disclosure, "total solid content in the latent heat storage material" means the total mass of the latent heat storage material when the latent heat storage material does not contain a solvent, and means the mass of the residue after removing the solvent from the latent heat storage material when the latent heat storage material contains a solvent. In this disclosure, "solvent" means diluents such as water and organic solvents.

[0028] 〔binder〕 The latent heat storage material of the present disclosure may contain a binder. Examples of binders include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include acrylic resins, polyacetal, polyamide, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polystyrene, polyphenylene sulfide, polyvinyl chloride, ABS (acrylonitrile butadiene styrene) resins, and AS (acrylonitrile styrene) resins. Examples of the thermosetting resin include phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester, diallyl phthalate resin, urethane resin, and silicone resin. The binder may contain, for example, an epoxy or acrylic monomer and a reaction initiator thereof. In this case, the binder can be polymerized by UV curing or heating and used as a latent heat storage material.

[0029] Moreover, rubbers can also be used as the binder. Examples of rubber include butadiene rubber, isoprene rubber, chloroprene rubber, halogenated butyl rubber, fluororubber, urethane rubber, acrylic rubber (ACM) obtained by copolymerization of an acrylic acid ester with another monomer, ethylene-propylene rubber obtained by coordination polymerization of ethylene and propylene using a Ziegler catalyst, butyl rubber (IIR) obtained by copolymerization of isobutylene and isoprene, styrene-butadiene rubber (SBR) obtained by copolymerization of butadiene and styrene, acrylonitrile-butadiene rubber (NBR) obtained by copolymerization of acrylonitrile and butadiene, and silicone rubber.

[0030] Moreover, examples of the binder include thermoplastic elastomers (TPE). Examples of the thermoplastic elastomer include an olefin-based thermoplastic elastomer (TPO), a styrene-based thermoplastic elastomer (TPS), an amide-based thermoplastic elastomer (TPA), and a polyester-based thermoplastic elastomer (TPC).

[0031] In addition, polyethylene glycol (PEG) having a molecular weight of 600 or more and modified products thereof, or polyurethanes in which PEG is crosslinked with diisocyanate as described in Non-Patent Document 7 have a latent heat of about 100 to 150 J / g, and are therefore preferable as binders to be used in combination with the compound represented by formula (I) of the present disclosure.

[0032] [Non-patent literature] Non-Patent Document 7: C. Alkan, E. Gunther, S. Hiebler, Oemer F. Ensari, D. Kahraman, “Polyurethanes as solid-solid phase change materials for thermal energy storage,” Solar Energy vol. 86 (2012) pp. 1761-1769

[0033] When the latent heat storage material of the present disclosure contains a binder, it may contain only one type of binder, or may contain two or more types of binder.

[0034] When the latent heat storage material of the present disclosure contains a binder, the content of the binder is not particularly limited, but is, for example, preferably 5% by mass to 95% by mass, more preferably 10% by mass to 50% by mass, and even more preferably 10% by mass to 30% by mass, relative to the total solid content in the latent heat storage material.

[0035] [Other ingredients] The latent heat storage material of the present disclosure may contain components (so-called other components) other than the components described above, as necessary, to the extent that the effects of the latent heat storage material are not impaired. Examples of other components include various additives such as dispersants, dispersion aids, antifungal agents, antistatic agents, antioxidants, binders, thermally conductive materials, electrically conductive materials, flame retardant materials, etc. The additives may be ones that perform two or more functions.

[0036] When the latent heat storage material of the present disclosure contains other components, the content of the other components can be appropriately set within a range that does not impair the effect of the latent heat storage material of the present disclosure.

[0037] Phase change temperature and latent heat The phase change temperature of the latent heat storage material of the present disclosure is preferably 8° C. or lower, more preferably 65° C. or lower, and even more preferably 60° C. or lower. In particular, when the phase change temperature of the latent heat storage material of the present disclosure is 78° C. or lower, there is a tendency that deterioration in performance of an article to which the latent heat storage material is applied (eg, an electronic device, a battery, or other article) can be particularly effectively suppressed. The lower limit of the phase change temperature of the latent heat storage material of the present disclosure is not particularly limited, but is, for example, preferably 25°C or higher, more preferably 30°C or higher, and even more preferably 35°C or higher. Furthermore, since the smaller the difference between the melting temperature and the solidification temperature, or the hysteresis, the more advantageous it is for the expression of repeatability, the temperature is preferably 15° C. or less, and more preferably 10° C. or less.

[0038] The latent heat quantity of the latent heat storage material of the present disclosure is not particularly limited, but is, for example, more preferably 150 J / g or more, and even more preferably 200 J / g or more. The higher the latent heat amount of the latent heat storage material of the present disclosure, the more preferable it is, and there is no particular upper limit.

[0039] The phase change temperature of the latent heat storage material of the present disclosure is the endothermic peak temperature during heating measured under the following conditions using a differential scanning calorimeter (DSC) as a measuring device. The latent heat quantity of the latent heat storage material of the present disclosure is the heat quantity of the endothermic peak during temperature rise measured under the following conditions using a differential scanning calorimeter as a measuring device. The differential scanning calorimeter used for the measurements was a Hitachi High-Tech Science differential scanning calorimeter (model: DSC7020), but the type of differential scanning calorimeter is not limited to this.

[0040] -conditions- Measurement temperature range: 30℃~150℃ or 30℃~200℃ Heating rate: 10℃ / min Atmosphere gas: Nitrogen Measurement sample amount: Accurately weigh out approx. 6.0 mg

[0041] <Applications of latent heat storage materials> The application of the latent heat storage material of the present disclosure is not particularly limited. The latent heat storage material of the present disclosure is a latent heat storage material that utilizes the latent heat associated with a phase change from a solid phase to a liquid phase, i.e., due to melting, and particularly when it contains a compound represented by formula (I), it has a low phase change temperature of 78°C or less, a large amount of latent heat, small hysteresis, and repeatability, making it suitable as a latent heat storage material for use in electronic devices or electricity storage devices. Specific examples of the electronic device and the power storage device will be described later, and therefore will not be described here.

[0042] The preferred latent heat storage material of the present disclosure (a latent heat storage material containing a compound represented by formula (I)) has a low phase change temperature of 78°C or less, a large amount of latent heat, small hysteresis, and a repeatability characteristic, and therefore can maintain the characteristics, life, and safety of electronic devices and electricity storage devices for a long period of time. The preferred latent heat storage material of the present disclosure is particularly suitable as a latent heat storage material used in high-output and high-capacity electricity storage devices that are accompanied by high temperatures and the generation of large amounts of heat.

[0043] [Latent heat storage material] The latent heat storage body of the present disclosure includes the latent heat storage material of the present disclosure. Since the latent heat storage medium of the present disclosure contains the latent heat storage material of the present disclosure, it preferably has a low phase change temperature of 78° C. or less, a large amount of latent heat, small hysteresis, and repeatability.

[0044] The shape of the latent heat storage material of the present disclosure is not particularly limited and can be appropriately set depending on the purpose. The latent heat storage material of the present disclosure may have a planar shape or a three-dimensional shape. Examples of the planar shape include a sheet shape and a film shape. The three-dimensional shape is not particularly limited, and can be appropriately set according to, for example, the shape of an object to which the latent heat storage material of the present disclosure is applied.

[0045] The method for producing the latent heat storage material of the present disclosure is not particularly limited. The latent heat storage medium of the present disclosure can be produced, for example, by a known method using the latent heat storage material of the present disclosure and a solvent.

[0046] The latent heat storage material of the present disclosure can be produced, for example, by the following method X.

[0047] (Method X) A latent heat storage body forming composition containing the latent heat storage material of the present disclosure containing a compound represented by formula (I) and a binder, and a solvent is applied onto a temporary support to form a coating film of the latent heat storage body forming composition. Next, the coating film of the latent heat storage body forming composition is dried to form a latent heat storage body on the temporary support. Next, the temporary support is peeled off from the latent heat storage body to produce a planar latent heat storage body. Alternatively, a composition consisting of the compound represented by formula (I) and, for example, an epoxy or acrylic monomer and an initiator (for example, an imidazole compound in the former case, or a peroxide in the latter case) is applied to form a coating film of the composition for forming a latent heat storage material. It is then polymerized by irradiation with ultraviolet light or heating to form a latent heat storage material.

[0048] The solvent in method X is not particularly limited. Examples of the organic solvent include aprotic polar solvents such as alcohol solvents (e.g., methanol, ethanol, n-propanol, and i-propanol), ketone solvents (e.g., acetone, methyl ethyl ketone, and cyclohexanone), chlorine solvents (e.g., chloroform and dichloromethane), tetrahydrofuran, acetonitrile, ethyl acetate, toluene, dimethylformamide, and hexamethylphosphoric triamide. A mixture of organic solvents is also acceptable.

[0049] The content of the solvent in the latent heat storage material forming composition is not particularly limited, and can be appropriately set depending on, for example, the types and amounts of components blended in the latent heat storage material forming composition.

[0050] In the composition for forming a latent heat storage material, the compound represented by formula (I) and the binder may simply be mixed together. The method for mixing the compound represented by formula (I) and the binder is not particularly limited, and examples thereof include a method in which they are mixed by stirring. The stirring means is not particularly limited, and a general stirring device can be used. Examples of the stirring device include a roll mill, a three-one motor equipped with a stirrer, a mixer such as a paddle mixer or an impeller mixer, and a mechanical stirring device. The stirring time is not particularly limited and can be appropriately set depending on the type of stirring device, the composition of the latent heat storage material forming composition, etc. Heating can also be performed as necessary.

[0051] The temporary support is not particularly limited. Examples of the temporary support include a metal plate, a glass plate, a resin sheet, and various films. The surface of the resin sheet may be subjected to a release treatment.

[0052] The size of the temporary support is not particularly limited, and can be appropriately set according to, for example, the size of the latent heat storage medium. The thickness of the temporary support is not particularly limited, and is appropriately set in consideration of, for example, workability.

[0053] The method for applying the latent heat storage material forming composition onto the temporary support is not particularly limited, and examples include methods using a spray coater, dip coater, gravure coater, reverse coater, die coater, knife coater, applicator, doctor blade, bar coater, etc.

[0054] The method for drying the coating film of the latent heat storage material-forming composition is not particularly limited, and examples thereof include a method using a heating device such as an oven. The drying temperature and drying time are not particularly limited as long as they can volatilize the solvent contained in the coating film of the latent heat storage material forming composition.

[0055] The latent heat storage material of the present disclosure can be produced by, for example, the following method Y in addition to the above method X.

[0056] (Method Y) The latent heat storage material of the present disclosure, which contains the compound represented by formula (I) and a binder, and a mixture containing a solvent as necessary, are kneaded using a kneader while being heated to obtain a kneaded product. The kneaded product is then molded to produce the latent heat storage material of the present disclosure.

[0057] The solvent in the method Y has the same meaning as the solvent in the method X.

[0058] When the mixture contains a solvent, the content of the solvent in the mixture is not particularly limited and can be set appropriately depending on, for example, the types and amounts of components blended in the mixture.

[0059] In the mixture, the compound represented by formula (I) and the binder do not necessarily have to be compatible with each other, but they may simply be mixed together. The method for mixing the compound represented by formula (I) and the binder is not particularly limited, and examples thereof include a method in which they are mixed by stirring. The stirring means is not particularly limited, and a general stirring device can be used as in method X.

[0060] The heating temperature of the mixture is not particularly limited and can be appropriately set depending on, for example, the type of binder. The heating temperature is preferably a temperature at which the binder can be melted, and can be, for example, 130°C to 170°C.

[0061] The kneading means is not particularly limited, and a general kneading device can be used. Examples of the kneading device include a mixer, a two-roll mill, and a kneader. The kneading conditions are not particularly limited and can be appropriately set depending on the type of kneading device, the composition of the mixture, and the like.

[0062] Examples of the molding process include press molding, extrusion molding, injection molding, in-mold molding, and molding using a three-dimensional modeling machine. The molding conditions are not particularly limited, and can be appropriately set depending on, for example, the type of molding device, the composition of the mixture, and the size of the latent heat storage medium.

[0063] [Electronic Devices] The electronic device of the present disclosure includes the latent heat storage material of the present disclosure, and may include a latent heat storage body containing the latent heat storage material of the present disclosure (i.e., the latent heat storage body of the present disclosure). Since the electronic device of the present disclosure includes the latent heat storage material of the present disclosure, the characteristics, lifespan, and safety of the electronic device can be maintained for a long period of time. Examples of electronic devices according to the present disclosure include semiconductor devices such as integrated circuits (ICs) and IC modules, and light emitting diode (LED) devices.

[0064] The form in which the electronic device of the present disclosure includes the latent heat storage material of the present disclosure is not particularly limited. In the case where the electronic device of the present disclosure is, for example, a semiconductor device, a planar (for example, sheet-shaped) latent heat storage material of the present disclosure (i.e., a latent heat storage material containing the latent heat storage material of the present disclosure) is disposed between the semiconductor device and a heat sink. According to such an embodiment, the heat generated in the semiconductor device is absorbed as latent heat by the compound represented by formula (I) contained in the latent heat storage material of the present disclosure, and the compound represented by formula (I) undergoes a phase change. During the phase change, the temperature is kept constant, so that the semiconductor device can be kept at a constant temperature. The heat stored by the compound represented by formula (I) can also be transported by, for example, a heat sink and dissipated.

[0065] [Electricity storage device] The power storage device of the present disclosure includes the latent heat storage material of the present disclosure, and may include a latent heat storage body containing the latent heat storage material of the present disclosure (i.e., the latent heat storage body of the present disclosure). Since the electricity storage device of the present disclosure includes the latent heat storage material of the present disclosure, the characteristics, lifespan, and safety of the electricity storage device can be maintained for a long period of time. An example of the power storage device of the present disclosure is a battery. Examples of the battery include a lithium ion battery and an all-solid-state battery thereof.

[0066] The embodiment in which the power storage device of the present disclosure includes the latent heat storage material of the present disclosure is not particularly limited, and for example, the embodiment shown in Non-Patent Document 8 can be used. That is, when the power storage device of the present disclosure is, for example, a lithium ion battery, an embodiment in which a three-dimensional latent heat storage body of the present disclosure (i.e., a latent heat storage body including the latent heat storage material of the present disclosure) is arranged between the battery cells and / or between the battery cells and the heat sink so as to cover all or a part of the battery cells can be exemplified. According to such an embodiment, the compound represented by formula (I) contained in the latent heat storage material of the present disclosure absorbs the heat generated in the battery cells as latent heat, and the compound represented by formula (I) undergoes a phase change. Since the temperature is kept constant during the phase change, the inside of the battery module can be kept at a constant temperature. The heat stored by the compound represented by formula (I) is, for example, thermally transported by a heat sink and dissipated. [Non-patent literature] [Non-Patent Document 8] Qian Wang, Bin Jiang, Bo Li, Yuying Yan, “A critical review of thermal management models and solutions of lithium-ion batteries for the development of pure electric vehicles Renewable and Sustainable Energy Reviews” Vol.64(2016)pp.106-128 EXAMPLES

[0067] The compounds and latent heat storage materials of the present disclosure will be described in more detail below with reference to examples. The present disclosure is not limited to the following examples as long as they do not depart from the gist of the disclosure.

[0068] The nuclear magnetic resonance (NMR) spectrum of each compound was measured using a Varian nuclear magnetic resonance spectrometer (model: UNITY INOVA 500 (500 MHz)). The infrared absorption spectrum of each compound was measured using a JASCO Fourier transform infrared spectrophotometer (model: FT / IR-400).

[0069] [Synthesis of dialkyl dicarboxylates, n=m] [Synthesis Example 1] Compound 1: Didodecyl malonate [C 12 H 25 OOCCH 2 COOC 12 H 25 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of dodecanol, 0.5 molar equivalent of malonic acid to the dodecanol, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 15 hours. After the heating and refluxing, the dichloromethane solution was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the target compound 1.

[0070] The obtained compound 1 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, which identify compound 1 as didodecyl malonate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.145(4H t / J=7.0Hz),3.362(2H s * ), 1.565(4H quintet * / J=7.5Hz), 1.336-1.280(36H m * ), 0.877(6H t * / J=7.0Hz) FT-IR νmax(cm -1 ):2918,2849,1735,1464,1360,1185 *Here, s is a singlet, t is a triplet, quintet is a quintet, m is a multiplet, and J is a coupling constant. FT-IR is shown in wave numbers.

[0071] [Synthesis Example 2] Compound 2: Dioctadecyl malonate [C 18 H 37 OOCCH 2 COOC 18 H 37 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of octadecanol, 0.5 equivalents of malonic acid, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 15 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 2.

[0072] The obtained compound 2 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 2 as dioctadecyl malonate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.131(4H t / J=7.0Hz),3.362(2H s),1.549(4H quintet / J=7.5Hz),1.344-1.252(60H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2849,1736,1473,1463,1359,1185 [Synthesis Example 3] Compound 3: Didodecyl glutarate [C 12 H 25 OOCC 3 H 6 COOC 12 H 25 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of dodecanol, 0.5 molar equivalent of glutaric acid to the dodecanol, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 15 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the target compound 3.

[0073] The obtained compound 3 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 3 as didodecyl glutarate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.073(4H t / J=7.0Hz),2.378(4H t / J=7.5Hz),1.960(2H quintet / J=7.0Hz),1.624(4H quintet / J=7.0Hz) 1.336‐1.252(36H m),0.878(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2918,2849,1738,1474,1281,1170

[0074] [Synthesis Example 4] Compound 4: Dioctadecyl glutarate [C 18 H 37 OOCC 3 H 6 COOC 18 H 37 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of octadecanol and 0.5 molar equivalent of glutaric acid to the above octadecanol, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour, and then heated and refluxed for 20 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture, and the solvent was removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the target compound 4.

[0075] The obtained compound 4 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 4 as dioctadecyl glutarate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.059(4H t / J=6.8Hz),2.362(4H t / J=7.5Hz),1.945(2H quintet / J=7.3Hz),1.610(4H quintet / J=7.0Hz) 1.339‐1.254(60H m),0.878(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2849,1737,1474,1174

[0076] [Synthesis Example 5] Compound 5: Dieicosyl glutarate [C 20 H 41 OOCC 3 H 6 COOC 20 H 41 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of eicosanol, 0.5 molar equivalent of glutaric acid to the above eicosanol, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 20 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 5.

[0077] The obtained compound 5 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and from these results, compound 5 is identified as dioctadecyl glutarate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.056(4H t / J=6.8Hz),2.364(4H t / J=7.5Hz),1.944(2H quintet / J=7.3Hz),1.607(4H quintet / J=7.0Hz)1.400‐1.200(68H m),0.874(6H t / J=6.8Hz) FT-IR νmax(cm -1 ):2917,2849,1738,1474,1282,1176 [Synthesis of dialkyl dicarboxylates, n ≠ m]

[0078] [Synthesis Example 6] Compound 6: Succinic acid monooctadecyl ester [C 18 H 37 OOCC 2 H 4 COOH] Octadecanol and an equimolar amount of succinic anhydride were dissolved in toluene and reacted under reflux for 2 hours. After the reaction was completed, the mixture was cooled and the solvent was removed under reduced pressure to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 6.

[0079] The obtained compound 6 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 6 as succinic acid monooctadecyl ester. 1 H-NMR (500 MHz, CDCl 3)δ(ppm):4.086(2H t / J=6.8Hz),2.698-2.669(2H m),2.637-2.607(2H m),1.629-1.600(2H m)1.400-1.150(30H m),0.878(3H t / J=7.0Hz) FT-IR νmax(cm -1 ):3323,2917,2849,1735,1716,1473,1359,1185

[0080] [Synthesis Example 7] Compound 7: Succinic acid octadecyl dodecyl ester [C 18 H 37 OOCC 2 H 4 COOC 12 H 25 ] The succinic acid monooctadecyl ester synthesized in Synthesis Example 6 in an equimolar amount to dodecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 7.

[0081] The obtained compound 7 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 7 as succinic acid octadecyl dodecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.074(4H t / J=6.8Hz),2.618(4H s),1.610(4H quintet / J=7.0Hz)1.360‐1.200(48H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2849,1737,1474,1174

[0082] [Synthesis Example 8] Compound 8: Octadecyltetradecyl succinate [C 18 H 37 OOCC 2 H 4 COOC 14 H 29 ] The succinic acid monooctadecyl ester synthesized in Synthesis Example 6 in an equimolar amount to tetradecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 8.

[0083] The obtained compound 8 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 8 as succinic acid octadecyl tetradecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.075(4H t / J=6.8Hz),2.619(4H s),1.641(4H quintet / J=7.0Hz)1.380-1.200(52H m),0.878(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2919,2850,1738,1474,1289,1174

[0084] [Synthesis Example 9] Compound 9: Succinic acid octadecyl hexadecyl ester [C 18 H 37 OOCC 2 H 4 COOC 16 H 33 ] The succinic acid monooctadecyl ester synthesized in Synthesis Example 6 in an equimolar equivalent to hexadecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, it was heated to reflux for 20 hours. After heating to reflux and cooling to room temperature, it was washed with an aqueous sodium hydrogen carbonate solution and water, anhydrous sodium sulfate was added to remove moisture, and then the solvent was removed to obtain colorless crystals. Recrystallization of the obtained crystals using n-hexane gave the target compound 9.

[0085] For the obtained compound 9 1 The results of the absorption spectra by 1H-NMR spectrum and Fourier transform infrared spectroscopy (FT-IR) are shown below. From these results, it was identified that compound 9 is octadecyl hexadecyl succinate. 1 1H-NMR (500 MHz, CDCl 3 3) δ (ppm): 4.065 (4H t / J = 6.8 Hz), 2.620 (4H s), 1.615 (4H quintet / J = 7.0 Hz) 1.380 - 1.200 (56H m), 0.876 (6H t / J = 7.0 Hz) FT-IR νmax (cm -1 -1): 2917, 2849, 1737, 1474, 1174

[0086] [Synthesis Example 10] Compound 10: Octadecyl eicosyl succinate [C 18 H 37 OOCC 2 H 4 COOC 20 H 41 The succinic acid monooctadecyl ester synthesized in Synthesis Example 6 in an equimolar equivalent to eicosanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, it was heated to reflux for 20 hours. After heating to reflux and cooling to room temperature, it was washed with an aqueous sodium hydrogen carbonate solution and water, anhydrous sodium sulfate was added to remove moisture, and then the solvent was removed to obtain colorless crystals. Recrystallization of the obtained crystals using n-hexane gave the target compound 10.

[0087] ​The obtained compound 10 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 10 as succinic acid octadecyl eicosyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.070(4H t / J=6.8Hz),2.618(4H s),1.640(4H quintet / J=7.0Hz)1.380-1.200(64H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2849,1737,1474,1174

[0088] [Synthesis Example 11] Compound 11: Succinic acid octadecyl docosyl ester [C 18 H 37 OOCC 2 H 4 COOC 22 H 45 ] The succinic acid monooctadecyl ester synthesized in Synthesis Example 6 in an equimolar amount to docosanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 11.

[0089] The obtained compound 11 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 11 as succinic acid octadecyl docosyl ester. 1 H-NMR (500 MHz, CDCl 3)δ(ppm):4.075(4H t / J=6.8Hz),2.617(4H s),1.642(4H quintet / J=7.0Hz)1.380-1.210(68H m),0.878(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2916,2847,1735,1471,1173

[0090] [Synthesis Example 12] Compound 12: Glutaric acid monooctadecyl ester [C 18 H 37 OOCC 3 H 6 COOH] Octadecanol and an equimolar amount of glutaric anhydride were dissolved in toluene and reacted under reflux for 2 hours. After the reaction was completed, the mixture was cooled and the solvent was removed under reduced pressure to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 12.

[0091] The obtained compound 12 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 12 as glutaric acid monooctadecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.086(2H t / J=6.8Hz),2.698-2.669(2H m),2.637-2.607(2H m),1.629-1.600(2H m)1.400-1.150(30H m),0.878(3H t / J=7.0Hz) FT-IR νmax(cm -1 ):3444,2918,2850,1730,1694,1463,1298,1183

[0092] [Synthesis Example 13] Compound 13: Octadecyltetradecyl succinate [C 18 H 37 OOCC 3 H 6 COOC 14 H 29] The glutaric acid monooctadecyl ester synthesized in Synthesis Example 12 in an equimolar amount to tetradecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 13.

[0093] The obtained compound 13 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 13 as glutaric acid octadecyl tetradecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.056(4H t / J=6.8Hz),2.362(4H t / J=7.3Hz),1.943(2H quintet / J=7.3Hz),1.607(4H quintet / J=7.0Hz)1.390‐1.195(52H m),0.875(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2919,2850,1738,1474,1289,1174

[0094] [Synthesis Example 14] Compound 14: Glutaric acid octadecyl hexadecyl ester [C 18 H 37 OOCC 3 H 6 COOC 16 H 33 ] The glutaric acid monooctadecyl ester synthesized in Synthesis Example 12 in an equimolar amount to hexadecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. The mixture was stirred at room temperature for 1 hour, and then heated under reflux for 20 hours. After heating under reflux, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 14.

[0095] The obtained compound 14 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 14 as glutaric acid octadecyl hexadecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.061(4H t / J=6.8Hz),2.366(4H t / J=7.5Hz),1.948(2H quintet / J=7.3Hz),1.612(4H quintet / J=7.0Hz)1.380‐1.200(56H m),0.879(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2850,1736,1474,1175

[0096] [Synthesis Example 15] Compound 15: Glutaric acid octadecyl heptadecyl ester [C 18 H 37 OOCC 3 H 6 COOC 17 H 35 ] The glutaric acid monooctadecyl ester synthesized in Synthesis Example 12 in an equimolar amount to heptadecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 15.

[0097] The obtained compound 15 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 15 as glutaric acid octadecylheptadecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.059(4H t / J=6.8Hz),2.362(4H t / J=7.5Hz),1.945(2H quintet / J=7.5Hz),1.609(4H quintet / J=7.0Hz)1.380‐1.200(58H m),0.876(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2849,1739,1283,1175

[0098] [Synthesis Example 16] Compound 16: Glutaric acid octadecyl nonadecyl ester [C 18 H 37 OOCC 3 H 6 COOC 19 H 39 ] The glutaric acid monooctadecyl ester synthesized in Synthesis Example 12 in an equimolar amount to nonadecanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 16.

[0099] The obtained compound 16 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 16 as glutaric acid octadecylnonadecyl ester. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.059(4H t / J=6.8Hz),2.362(4H t / J=7.3Hz),1.945(2H quintet / J=7.3Hz),1.609(4H quintet / J=7.0Hz)1.390‐1.200(62H m),0.876(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2918,2849,1739,1727,1474,1284,1175

[0100] [Synthesis Example 17] Compound 17: Glutaric acid octadecyl eicosyl ester [C 18 H 37 OOCC 3 H 6 COOC 20 H 41 ] The glutaric acid monooctadecyl ester synthesized in Synthesis Example 12 in an equimolar amount to eicosanol was dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated and refluxed for 20 hours. After heating and refluxing, the mixture was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired compound 17.

[0101] The obtained compound 17 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below, and the results identify compound 17 as glutaric acid octadecyl eicosyl ester. 1H-NMR (500 MHz, CDCl 3 ) δ (ppm): 4.055 (4H t / J = 7.0 Hz), 2.360 (4H t / J = 7.3 Hz), 1.942 (2H quintet / J = 7.5 Hz), 1.607 (4H quintet / J = 7.3 Hz) 1.400 - 1.200 (64H m), 0.878 (6H t / J = 7.0 Hz) FT-IR νmax (cm -1 ): 2849, 1739, 1474, 1286, 1175

[0102] [Synthesis Example 18] Compound 18: Octadecyl docosyl glutarate [C 18 H 37 OOCC 3 H 6 COOC 22 H 45 An equimolar equivalent of the monooctadecyl glutarate synthesized in Synthesis Example 12 and docosanol were dissolved in dichloromethane, and a small amount of concentrated sulfuric acid was added. After stirring at room temperature for 1 hour, the mixture was heated to reflux for 20 hours. After heating to reflux and cooling to room temperature, the mixture was washed with an aqueous sodium hydrogen carbonate solution and water, anhydrous sodium sulfate was added to remove moisture, and then the solvent was removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the target compound 18.

[0103] The 1 results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) of the obtained Compound 18 are shown below. From these results, it is identified that Compound 16 is octadecyl docosyl glutarate. 1 H-NMR (500 MHz, CDCl 3 ) δ (ppm): 4.056 (4H t / J = 6.8 Hz), 2.363 (4H t / J = 7.5 Hz), 1.944 (2H quintet / J = 7.5 Hz), 1.602 (4H quintet / J = 7.0 Hz) 1.380 - 1.200 (68H m), 0.875 (6H t / J = 7.0 Hz) FT-IR νmax (cm -1 ​):2918,2849,1738,1474,1288,1174

[0104] [Comparative Synthesis Example 1] Comparative compound 1: Didodecyl succinate [C 12 H 25 OOCCH 2 CH 2 COOC 12 H 25 ] It was synthesized in the same manner as in Non-Patent Document 9 below.

[0105] [Comparative Synthesis Example 2] Comparative compound 2: Dioctadecyl succinate [C 18 H 37 OOCCH 2 CH 2 COOC 18 H 37 ] As in Comparative Synthesis Example 1, synthesis was carried out in the same manner as in Non-Patent Document 9. [Prior art documents]

[0106] [Non-Patent Document 9] Derya Kahraman Doguscu, “Synthesis and characterization of ditetradecyl succinate and dioctadecyl succinate as novel phase change materials for thermal energy storage” Solar Energy Materials & Solar cells vol.200(2019)110006)

[0107] [Comparative Synthesis Example 3] Comparative compound 3: Didodecyl adipate [C 12 H 25 OOC(CH 2 ) 4 COOC 12 H 25 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of dodecanol, 0.5 molar equivalent of adipic acid to the dodecanol, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 20 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired comparative compound 3.

[0108] The obtained comparative compound 3 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below. From these results, comparative compound 3 is identified as didodecyl adipate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.089(4H t / J=7.0Hz),2.320(4H m),1.665-1.565(8H m),1.345-1.254(36H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2918,2850,1735,1463

[0109] [Comparative Synthesis Example 4] Comparative Compound 4: Dioctadecyl adipate [C 18 H 37 OOC(CH 2 ) 4 COOC 18 H 37 Synthesis of A small amount of concentrated sulfuric acid was added dropwise to a mixture of octadecanol, 0.5 equivalents of adipic acid, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 22 hours. The dichloromethane solution after heating under reflux was cooled to room temperature, washed with aqueous sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired comparative compound 4.

[0110] The obtained comparative compound 4 1 The results of the H-NMR spectrum and the absorption spectrum by Fourier transform infrared spectroscopy (FT-IR) are shown below. From these results, comparative compound 4 is identified as dioctadecyl adipate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.085(4H t / J=7.0Hz),2.322(4H m),1.665-1.565(8H m),1.400-1.200(60H m),0.887(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2851,1732,1463

[0111] [Comparative Synthesis Example 5] Comparative compound 5: Didodecyl suberate [C 12 H 25 OOC(CH 2 ) 6 COOC 12 H 25 ] A small amount of concentrated sulfuric acid was added dropwise to a mixture of dodecanol, 0.5 molar equivalent of suberic acid to the dodecanol, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 20 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired comparative compound 5.

[0112] The obtained comparative compound 5 1 The results of H-NMR spectrum and Fourier transform infrared spectroscopy (FT-IR) absorption spectrum are shown below, which identify Comparative Compound 5 as didodecyl suberate. 1 H-NMR (500 MHz, CDCl 3)δ(ppm):4.048(4H t / J=6.8Hz),2.286(4H t / J=7.5Hz),1.635-1.552(8H m),1.336-1.280(40H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2916,2849,1736,1464,1360,1185

[0113] [Comparative Synthesis Example 6] Comparative Compound 6: Dioctadecyl Suberate [C 18 H 37 OOC(CH 2 ) 6 COOC 18 H 37 ]

[0114] A small amount of concentrated sulfuric acid was added dropwise to a mixture of octadecanol, 0.5 equivalents of suberic acid, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 20 hours. The dichloromethane solution after heating under reflux was cooled to room temperature, washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired comparative compound 6. The obtained comparative compound 6 1 The results of H-NMR spectrum and Fourier transform infrared spectroscopy (FT-IR) absorption spectrum are shown below. From these results, comparative compound 6 is identified as dioctadecyl suberate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.050(4H t / J=7.0Hz),2.282(4H t / J=7.5Hz),1.640-1.555(8H m),1.334-1.282(64H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2918,2849,1726,1464,1360,1185

[0115] [Comparative Synthesis Example 7] Comparative Compound 7: Dioctadecyl Sebacate [C 18 H 37 OOC(CH 2 ) 8 COOC 18 H 37 ]

[0116] A small amount of concentrated sulfuric acid was added dropwise to a mixture of octadecanol, 0.5 equivalents of sebacic acid, and dichloromethane. After the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 20 hours. After the dichloromethane solution was cooled to room temperature, it was washed with an aqueous solution of sodium bicarbonate and water, and anhydrous sodium sulfate was added to remove moisture. The solvent was then removed to obtain colorless crystals. The obtained crystals were recrystallized using n-hexane to obtain the desired comparative compound 7. The obtained comparative compound 7 1 The results of H-NMR spectrum and Fourier transform infrared spectroscopy (FT-IR) absorption spectrum are shown below. From these results, comparative compound 6 is identified as dioctadecyl suberate. 1 H-NMR (500 MHz, CDCl 3 )δ(ppm):4.046(4H t / J=7.0Hz),2.280(4H t / J=7.5Hz),1.640-1.555(8H m),1.334-1.282(68H m),0.877(6H t / J=7.0Hz) FT-IR νmax(cm -1 ):2917,2851,1731,1464,1360,1185

[0117] [evaluation] (Examples 1 to 18 and Comparative Examples 1 to 7) The phase change temperature (unit: °C) and latent heat (unit: J / g) were measured for compounds 1 to 18 (Examples 1 to 18) synthesized in Synthesis Examples 1 to 18, comparative compounds 1 to 7 (Comparative Examples 1 to 7) synthesized in Comparative Synthesis Examples 1 to 7, and malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, and sebacic acid (Comparative Examples 8 to 13) before modification, and the presence or absence of repeatability was confirmed. The results are shown in Tables 1 and 2, and some of them are shown in Figures 2 to 5. The phase change temperature and latent heat were measured under the following conditions using a Hitachi High-Tech Science differential scanning calorimeter (model: DSC7020) as the measuring device. The phase change temperature is the endothermic peak temperature during heating, and the temperature difference between this and the exothermic peak during cooling is shown as hysteresis. The latent heat is the heat quantity of the endothermic peak during heating. The presence or absence of cycle characteristics was judged based on whether heat generation occurred during cooling. Specifically, if heat generation did not occur when the material was heated to 150°C and then cooled to 30°C over about one hour, it was judged not to have cycle characteristics. In this case, if the material exhibited cycle characteristics, they were shown as hysteresis temperatures in Tables 1 and 2.

[0118] -conditions- Measurement temperature range: 30°C to 150°C (30°C to 200°C for Reference Examples 1 to 3) Heating rate: 10℃ / min Atmosphere gas: Nitrogen Measurement sample amount: Accurately weigh out approx. 6.0 mg

[0119] The results of Examples 1 to 14 are shown in Table 1, and the results of Comparative Examples 1 to 9 are shown in Table 2.

[0120] [Table 1]

[0121] [Table 2]

[0122] The latent heats and melting points of dicarboxylic acid didodecyl esters with different carbon numbers per carbon in Tables 1 and 2, i.e., Example 1 (Compound 1), Example 3 (Compound 3), Comparative Example 1 (Comparative Compound 1), Comparative Example 3 (Comparative Compound 3), and Comparative Example 5 (Comparative Compound 5), are shown in Figure 2. Similarly, the latent heats and melting points of dioctadecyl esters, i.e., Example 2 (Compound 2), Example 4 (Comparative Compound 4), Comparative Example 2 (Comparative Compound 2), Comparative Example 4 (Comparative Compound 4), Comparative Example 6 (Comparative Compound 6), and Comparative Example 7 (Comparative Compound 7), are shown in Figure 3.

[0123] From FIG. 2, it is clear that the melting point is greatly reduced compared to the dicarboxylic acids (Reference Examples 1 to 6) shown in FIG. 1, and it can be seen that they are applicable to electronic device applications where a low melting point is desired. In addition, the melting points of the dicarboxylic acids in FIG. 1 are higher when the carbon number is even than when the carbon number is odd, and there is an even-odd effect. In other words, in the cases of succinic acid (l=2) and adipic acid (l=4), they are both higher than malonic acid (l=1) and glutaric acid (l=3), which are odd numbers. However, it can be seen that by esterification, the melting point is almost the same when l≧2, but is lower when l is 1 compared to l≧2. In addition, with regard to the amount of latent heat, Examples 1 and 3, which have odd numbers of l, are higher than Comparative Examples 1, 3, and 5, which have even numbers of l, and it can be seen that Examples 1 and 3 are more suitable for electronic device applications than Comparative Examples 1, 3, and 5.

[0124] The same is true for the dioctadecyl ester shown in FIG. 3, where it can be seen that when l is 1, the melting point can be lowered compared to l≧2. In addition, the amount of latent heat is higher in Examples 2, 4, and 5, where l is an odd number, compared to Comparative Examples 2, 4, 6, and 7, where l is an even number, and it was found that when the carbon number l is an odd number of 1 and 3, a higher amount of latent heat can be realized compared to when it is an even number, and this phenomenon can be generalized. In addition, as can be seen from the results of Examples 1 to 5, when the carbon number of the ester portion is increased, the amount of latent heat increases, but the melting point also tends to increase, which requires a new design guideline for electronic device applications where a low melting point is desired. In that sense, the malonic acid diester with l=1 is a more preferred design method.

[0125] As a phase change material, a method is known in which multiple substances with different carbon numbers of long-chain hydrocarbon compounds are mixed to lower the phase change temperature (melting point). For example, in the method of mixing myristic acid and caproic acid described in Non-Patent Document 9, the eutectic melting point is lowered, but the amount of latent heat is also known to be lowered. Also, Non-Patent Document 10 describes a mixture of caproic acid and octadecanol, which has multiple eutectic melting points, meaning that the difference between the melting point and the freezing point is large and the hysteresis is large, and this tendency is not suitable for application to cooling systems for electronic devices. [Prior art documents]

[0126] [Non-Patent Document 9] Dongyi Zhou, Yuhong Zhou, Yicai Liu, Xianzhi Luo, Jiawei Yuan, “Preparation and Performance of Capric-Myristic Acid Binary Eutectic Mixtures for Latent Heat Thermal Energy Storages”, Journal of Nanomaterials Vol.2019, Article ID 2094767, 9 pages [Non-Patent Document 10] Peixian Zuo, Zhong Liu, Hua Zhang, Dasong Dai, Ziyan Fu, Jorge Corker, Mizi Fan, “Formulation and phase change mechanism of Capric acid / Octadecanol binary composite phase change materials,” Energy Vol.270(2023)126943

[0127] In this disclosure, we propose to lower the melting point by mismatching the ester hydrocarbon chains in the dicarboxylate molecule. If there is a mismatch in the number of carbon atoms in the molecule, the latent heat does not decrease and hysteresis may also be reduced. The change in Gibbs free energy at the melting point is expressed by equation (1), ΔG m = ΔH m - T m ΔS m Formula (1) ΔG during melting m = 0, so the melting point T m is expressed as the relationship between enthalpy and entropy, as shown in the following equation (2), which suggests that the melting point can be lowered by increasing the entropy during melting. TIFF2025079755000006.tif1986Factors that affect entropy include molecular symmetry, flexibility, and eccentricity, and it has been reported that molecules with high symmetry have high melting points, as described in Non-Patent Document 10. Therefore, we considered changing the number of carbon atoms in the ester portion of the synthesized dicarboxylate diester to disrupt the symmetry within the molecule and lower the melting point. [Non-Patent Document 11] Samuel H. Yalokowsky, "Carnelley's Rule and the Prediction of Melting Point" J. Pharmaceutical Sciences Vol. 103 (2014) pp. 2629-26 The results of latent heat and melting point when the carbon number of the ester part of the newly synthesized dicarboxylate diester is different, that is, when n ≠ m, are summarized in Examples 6 to 18 in Table 1. The relationship between the latent heat and melting point of succinic acid diester is shown in Examples 7 to 11 and Comparative Example 2 in FIG. 4. Specifically, the carbon number of one ester is fixed to 18, and the carbon number of the other is changed from 12 to 24. From this, the latent heat increases as the carbon number increases, but the melting point decreases beyond 18. In other words, compared to the dioctadecyl ester (Comparative Example 2) in which both carbon numbers are 18, the esters in which one carbon number is 20 and 22 can reduce the melting point despite the high latent heat. In addition, the hysteresis is small, at 7°C or less.

[0128] The relationship between the latent heat and the melting point in the case of glutaric acid diester is shown in Fig. 5 for Example 4 and Examples 13 to 18. Similarly, in this case, the tendency that the latent heat increases as the carbon number increases remains unchanged, but the melting point decreases after reaching a maximum of 18. In addition, the hysteresis is small, and the decrease in melting point due to a mismatch in the number of ester hydrocarbons in the dicarboxylate diester molecule can be generalized.

[0129] For example, when comparing the latent heat amounts when the melting point is 65°C or less, Comparative Examples 2, 4, and 6 have melting points of 64°C and latent heat amounts of 186 to 202 J / g, whereas Examples 16 to 18 have melting points of 60 to 63°C, which are low, but have latent heat amounts of 228 to 238 J / g, which are large compared to the comparative examples. In addition, when comparing the amounts of latent heat when the melting point is 50°C or less, the amounts of latent heat are 169 to 171 J / g in Comparative Examples 1, 3, and 5, whereas the amounts of latent heat are 195 to 203 J / g in Examples 7, 8, and 13, which are larger than the amounts in the Comparative Examples. In other words, when the carbon number of the diester in Table 1 is n ≠ m, it is possible to increase the carbon number to increase the latent heat while suppressing the increase in the melting point. This design method is more suitable for electronic device applications that require a high latent heat and a low melting point.

[0130] As disclosed herein, the decrease in melting point due to the mismatch of ester hydrocarbon chains in the dicarboxylate molecule does not decrease the latent heat and has small hysteresis compared to the case of a mixture, and is therefore considered to have high application value.

[0131] Similarly, in the case of the compounds in Examples 6 and 12 in which only one of the dicarboxylic acids is esterified, the melting points were 72°C and 78°C, respectively, while maintaining a high latent heat compared to the case of dicarboxylic acids, and were significantly reduced compared to the 183°C and 98°C before modification. In addition, while dicarboxylic acids do not generate heat when cooling, hysteresis is observed in the case of esterification on only one side, and therefore the repeated cycling characteristics have been improved.

[0132] From the above, it was found that in the dicarboxylate compound represented by formula (I), when the number of carbon atoms in the alkyl chain of the ester in formula (I) is n=m, malonic acid and glutaric acid with an odd number of l have a larger latent heat than those with an even number of l. In addition, when n≠m, the melting point can be reduced even if the number of carbon atoms is increased, and the latent heat can be further improved at a low melting point. In other words, these phase change materials provide latent heat storage materials with a low phase change temperature of 78°C or less, a large amount of latent heat, and repeatability. These results suggest that the same effect can be achieved regardless of the number of carbon atoms l, m, and n in formula (I).

Claims

Claim 1 A compound represented by the following formula (I). 【Chemical 1】 In the formula (I), when n = m, n is an integer from 1 to 30, l is an odd number less than 10; when n ≠ m, n and m are each independently, n is an integer from 0 to 30, m is an integer from 1 to 30, and l is an integer from 1 to 10. Claim 2 A latent heat storage material containing the compound according to Claim 1. Claim 3 The latent heat storage material according to Claim 2, which is used in an electronic device or an electric energy storage device. Claim 4 A latent heat storage body containing the latent heat storage material according to Claim 2. Claim 5 An electronic device provided with the latent heat storage material according to Claim 2. Claim 6 An electric energy storage device provided with the latent heat storage material according to Claim 2.

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