Novel compound and heat storage material

Abstract

To provide a novel compound having heat storage properties.SOLUTION: The compound of the present invention is represented by formula (1) (R1-R4 are each independently an acyl group derived from a C10-22 linear saturated fatty acid).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a novel compound, particularly to a novel compound that can be used as a phase change material (PCM). The present invention also relates to a heat storage material. [Background technology]

[0002] Heat storage technologies are classified as thermochemical technologies that utilize the sensible or latent heat of materials. The most common heat storage material today is water, which utilizes its sensible heat. Heat is stored for long periods in large water tanks, and its operation is based on the sensible heat, i.e., the specific heat capacity of water. Hot water tanks require efficient insulation, and their low energy density results in significant heat loss over long-term storage. On the other hand, latent heat storage is based on the utilization of latent heat of fusion and the crystallization of PCMs. When molecules transition from a kinetic state to a crystalline, immobile state, their kinetic energy is converted into thermal energy, which manifests as heat generation (heat dissipation). Generally, when a material is gradually cooled from a high temperature, molecular motion slows down, resulting in crystallization accompanied by heat generation (heat dissipation). Furthermore, when heat is applied to crystallized molecules, i.e., when the temperature is increased, the molecules absorb external thermal energy as kinetic energy (heat storage), causing the crystalline state to melt. In other words, melting occurs through an endothermic reaction (heat storage reaction). PCM heat storage materials utilize this heat generation (heat dissipation) and heat absorption (heat storage).

[0003] Some PCMs exhibit unusual behavior. For example, some compounds crystallize when heated, absorbing heat from their surroundings and generating additional heat. The crystals formed in this way are called cold crystals. The mechanism of cold crystallization involves amorphization (vitrification), in which molecules randomly align and their mobility decreases, rather than the usual crystallization in which molecules regularly align when cooled from a high temperature. Amorphous compounds maintain this amorphous state during cooling. During the heating process, the amorphous regions melt and molecular mobility increases as the temperature rises. This increased molecular mobility transforms the molecules into a more stable state (a molecularly aligned state), resulting in exothermic crystallization. This is cold crystallization (post-crystallization or cold crystallization). Further increasing the temperature causes these crystals to melt, absorbing heat. Polymers are generally known as compounds that exhibit this type of cold crystallization. Polymers contain both crystalline and amorphous regions within large molecules, and the molecular mobility of these amorphous regions leads to amorphization and cold crystallization. The heat generated (heat dissipation) during cold crystallization is utilized in heat storage materials that utilize the latent heat of PCMs. Known PCMs used as heat storage materials include glacial acetic acid (Patent Document 1), sodium pyrophosphate decahydrate (Patent Document 2), specific organic ligand polymers (Patent Document 3), specific N-salicylideneamine compounds (Patent Document 4), 2-amino-2-methyl-1,3-propanediol (Patent Document 5), and sugar alcohols such as erythritol (Patent Documents 6 and 7). Differential scanning calorimetry (DSC) is typically used to observe cold crystallization.

[0004] Incidentally, Non-Patent Documents 1 to 3 and Patent Document 8 describe compounds prepared by esterifying the hydroxyl group at the 6-position of glucono-δ-lactone (D-glucono-1,5-lactone). However, they do not describe whether the ester compounds are PCMs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-107035 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-219557 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-97530 [Patent Document 4] Japanese Patent Application Laid-Open No. 2013-216876 [Patent Document 5] Japanese Patent Application Publication No. 2019-77831 [Patent Document 6] Special Publication No. 2020-511555 [Patent Document 7] Japanese Patent Application Laid-Open No. 2016-69510 [Patent Document 8] U.S. Patent No. 5,505,938 [Non-patent literature]

[0006] [Non-Patent Document 1] Carbohydrate Research (1995), 274, 111-121. [Non-patent document 2] Journal of Carbohydrate Chemistry (1995), 14(2), 265-270. [Non-patent document 3] Comptes Rendus Chimie (2004), 7(6-7), 607-610. Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional PCMs are limited in variety and lack the versatility to be used for various purposes. Therefore, an object of the present invention is to provide novel compounds that can be used as PCMs. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems and have found that a compound of the following formula (1) exhibits a specific phase change temperature in DSC, thereby completing the present invention. That is, the present invention provides the following compound and heat storage material. [1] Formula (1): [ka] (1) (R 1 ~R 4 are each independently an acyl group derived from a linear saturated fatty acid having 10 to 22 carbon atoms. Compound. [2] Formula (2): [ka] (2) (R 1 ~R 4 The definition of is as described in [1] above. The compound according to [1] above, represented by the formula: [3] R 1 ~R 4 are all the same acyl group. [4] A composition comprising the compound according to any one of [1] to [3] above. [5] A heat storage material containing the compound according to any one of [1] to [3] above. [6] A method for producing the compound according to any one of the above [1] to [3], comprising the steps of: Formula (3): [ka] (3) The compound of formula (1): is reacted with a source of acyl group derived from a linear saturated fatty acid having 10 to 22 carbon atoms to obtain a compound of formula (1): [ka] (1) (R 1 ~R 4The definition of is as described in [1] above. A method of producing a compound of formula (I). [7] The production method according to [6] above, wherein the acyl group source comprises at least one selected from the group consisting of acid halides, acid anhydrides, and esters of linear saturated fatty acids having 10 to 22 carbon atoms. [Effects of the Invention]

[0009] According to the present invention, a novel compound that can be used as a PCM is provided, thereby increasing the options for PCMs that can also be used as heat storage materials. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows a DSC curve of the compound of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will now be described in further detail. The present invention relates to a compound of formula (1): [ka] (1) The compounds of the present invention are derivatives of glucono-1,4-lactone or stereoisomers thereof.

[0012] In formula (1), R 1 ~R 4 are each independently an acyl group derived from a linear saturated fatty acid having 10 to 22 or 12 to 18 carbon atoms. 4 forms an ester with the hydroxyl group at position 6, which is the most reactive group in the glucono-1,4-lactone structure. 3 It is believed that the formation of an ester in R increases the stability of the five-membered ring structure of glucono-1,4-lactone. 1 ~R 4 are all the same acyl group.

[0013] When the compounds of the present invention are subjected to DSC in a heating-cooling cycle, they exhibit an exothermic peak upon heating. This indicates the occurrence of cold crystallization, making the compounds of the present invention PCMs. Note that the term "phase change material (PCM)" used herein refers to a substance that releases or absorbs sufficient energy during a phase transition to generate usable heat or cooling. During the phase change, the temperature of the PCM remains constant at the phase change temperature. Therefore, PCMs can be used as heat storage materials and are useful for controlling repeated temperature differences (controlling temperature rise and fall), countering heat generation, and mitigating sudden temperature changes.

[0014] In one embodiment, the compound of the present invention has the formula (2): [ka] (2) In formula (2), R 1 ~R 4 is as defined above for formula (1). More specifically, the compounds of the present invention include, for example, 2,3,5,6-tetra-O-decanoyl-D-glucono-1,4-lactone (C10GL), 2,3,5,6-tetra-O-dodecanoyl-D-glucono-1,4-lactone (C12GL), 2,3,5,6-tetra-O-tetradecanoyl-D-glucono-1,4-lactone (C14GL), 2,3,5,6-tetra-O-palmitoyl-D-glucono-1,4-lactone (C16GL), 2,3,5,6-tetra-O-stearoyl-D-glucono-1,4-lactone (C18GL), 2,3,5,6-tetra-O-docosanoyl-D-glucono-1,4-lactone (C22GL), 2,3,5-tri-O-decanoyl-6-O-dodecanoyl-D-glucono-1,4-lactone (6LauC10GL), and 6-O-Palmitoyl-2,3,5-tri-O-stearoyl-D-glucono-1,4-lactone (6PalC18GL) etc. may also be used.

[0015] In another aspect, the present invention relates to a method for preparing a compound of formula (1) as described above as one aspect of the present invention, said method comprising the steps of: Formula (3): [ka] (3) with a source of acyl groups derived from linear saturated fatty acids having 10 to 22 or 12 to 18 carbon atoms to obtain a compound of formula (1): [ka] (1) (R 1 ~R 4 The definition of is as above) The method includes the step of producing a compound of formula (I).

[0016] The acyl group source can be any source commonly used in the art without any particular limitation, and may include, for example, at least one selected from the group consisting of acid halides, acid anhydrides, and esters of linear saturated fatty acids having 10 to 22 or 12 to 18 carbon atoms. Since the hydroxyl groups of the compound of formula (3) have different reactivities depending on the position, when acyl group sources having different carbon numbers are reacted simultaneously or successively, ester bonds having different acyl groups depending on the position can be formed.

[0017] The production method of the present invention may further include any step commonly used in the art, such as a step of isolating the compound of formula (1) produced, as long as the step does not impair the object of the present invention.

[0018] In another aspect, the present invention relates to a composition or a heat storage material comprising the compound of formula (1) described above as one aspect of the present invention. The composition or heat storage material of the present invention may further comprise any excipient and / or additive commonly used in the art, and may further comprise other PCMs, as long as the objective of the present invention is not impaired.

[0019] The present invention will be specifically explained below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0020] [Synthesis Example] The compound of the present invention was synthesized by introducing an acyl group into D-glucono-1,5-lactone according to the following scheme (see items (1) to (6) below for details). [ka]

[0021] (1) Synthesis of 2,3,5,6-tetra-O-decanoyl-D-glucono-1,4-lactone (C10GL; Compound 1) D-glucono-1,5-lactone (250 mg) was mixed with 4 equivalents of 4-dimethylaminopyridine (DMAP) (686 mg) and dissolved in 8 equivalents of pyridine (908 μL). 7.5 mL of toluene was added, and the mixture was stirred with a stirrer while adding 6 equivalents of decanoyl chloride (C 10 H 19 OCl (1.75 mL) was added and the mixture was stirred at room temperature under a nitrogen atmosphere for 1 day. After confirming the completion of the reaction by TLC (AcOEt:toluene = 1:20), 1 mL of water was added and the mixture was stirred at room temperature for 30 minutes. After extraction with chloroform, the concentrated liquid was purified by silica gel column chromatography (toluene) to obtain 265 mg of compound 1 (C10GL) (yield 24%). The chemical structure and properties of compound 1 were confirmed by nuclear magnetic resonance (NMR), mass spectrometry (MS), and optical rotation measurement. HMBC-NMR indicated that compound 1 was the desired five-membered ring compound cyclized by 1-4. TIFF2025131147000011.tif85170

[0022] (2) Synthesis of 2,3,5,6-tetra-O-dodecanoyl-D-glucono-1,4-lactone (C12GL; Compound 2) Four equivalents of DMAP (686 mg) were added to D-glucono-1,5-lactone (250 mg) and dissolved in 8 equivalents of pyridine (908 μL). 7.5 mL of toluene was added, and then 6 equivalents of lauroyl chloride (C 12 H 23 OCl (1.95 mL) was added and stirred at room temperature under a nitrogen atmosphere for 1 day. After confirming the completion of the reaction by TLC (AcOEt:toluene = 1:20), 1 mL of water was added and stirred at room temperature for 30 minutes. After acidifying the reaction with 6 mL of 2N-HCl, the reaction mixture was crystallized by adding 30 mL of methanol and 10 mL of ethanol. The resulting crystals were filtered through filter paper and washed with methanol to obtain 803 mg of compound 2 (C12GL) (yield 63%). HMBC-NMR revealed that compound 2 was the desired five-membered ring compound cyclized by 1-4. TIFF2025131147000012.tif85170

[0023] (3) Synthesis of 2,3,5,6-tetra-O-tetradecanoyl-D-glucono-1,4-lactone (C14GL; Compound 3) Four equivalents of DMAP (686 mg) were added to D-glucono-1,5-lactone (250 mg) and dissolved in 8 equivalents of pyridine (908 μL). 7.5 mL of toluene was added, and then 6 equivalents of myristoyl chloride (C 14 H 27 OCl (2.29 mL) was added and stirred at room temperature under a nitrogen atmosphere for 1 day. After confirming the completion of the reaction by TLC (AcOEt:toluene = 1:20), 1 mL of water was added and stirred at room temperature for 30 minutes. After acidifying the reaction with 6 mL of 2N-HCl, the reaction mixture was crystallized by adding 30 mL of acetone and 10 mL of ethanol. The resulting crystals were filtered through filter paper and washed with acetone to obtain 1.098 g of compound 3 (C14GL) (77% yield). HMBC-NMR indicated that compound 3 was the desired five-membered ring compound cyclized by 1-4. TIFF2025131147000013.tif85170

[0024] (4) Synthesis of 2,3,5,6-tetra-O-palmitoyl-D-glucono-1,4-lactone (C16GL; Compound 4) Four equivalents of DMAP (1.4 g) were added to D-glucono-1,5-lactone (500 mg) and dissolved in 8 equivalents of pyridine (1.82 mL). After adding 15 mL of toluene, the mixture was stirred with a stirrer and then dissolved in 6 equivalents of palmitoyl chloride (C 16 H 31 The mixture was added with 5.10 mL of AcOEt and stirred at room temperature under a nitrogen atmosphere for 1 day. After confirming the completion of the reaction by TLC (AcOEt:toluene = 1:20), acetone (30 mL) was added for crystallization. The resulting crystals were filtered through filter paper and washed with acetone. NMR analysis revealed that DMAP remained in the crystals. Therefore, the crystals were dissolved in toluene (20 mL), and 10 mL of 2N HCl was added. The mixture was stirred at room temperature for 30 minutes. 30 mL of acetone was added and crystallization was resumed. The resulting crystals were filtered through filter paper and washed with acetone to obtain 1.923 g of compound 4 (C16GL) (61% yield). HMBC-NMR analysis indicated that compound 4 was a five-membered ring cyclized by 1-4. TIFF2025131147000014.tif86170

[0025] (5) Synthesis of 2,3,5,6-tetra-O-stearoyl-D-glucono-1,4-lactone (C18GL; Compound 5) Four equivalents of DMAP (686 mg) were added to D-glucono-1,5-lactone (250 mg) and dissolved in 8 equivalents of pyridine (908 μL). 7.5 mL of toluene was added, and then 6 equivalents of stearoyl chloride (C 18 H 35HCl (2.84 mL) was added and stirred at room temperature under a nitrogen atmosphere for 1 day. After confirming the completion of the reaction by TLC (AcOEt:toluene = 1:20), 1 mL of water was added and stirred at room temperature for 30 minutes. After acidifying the reaction with 6 mL of 2N-HCl, the reaction mixture was crystallized by adding 20 mL of acetone / DMF (4:1). The resulting crystals were filtered through filter paper and washed with acetone / DMF (4:1), yielding 1.605 g of compound 5 (C18GL) (92% yield). HMBC-NMR indicated that compound 5 was a five-membered ring cyclized by 1-4. TIFF2025131147000015.tif87170

[0026] (6) Synthesis of 2,3,5,6-tetra-O-docosanoyl-D-glucono-1,4-lactone (C22GL; Compound 6) First, 6 equivalents of behenic acid (C 22 H 44 O2 (2.87 g) and 6 equivalents of DMF (652 μL) were dissolved in 20 mL of 1,2-dichloroethane, to which 30 equivalents of thionyl chloride (3.0 mL) was added and stirred at room temperature for 3 hours. The resulting solution was concentrated under reduced pressure and then dried in vacuo to obtain behenoyl chloride, which was then dissolved in 10 mL of toluene.

[0027] Next, 4 equivalents of DMAP (686 mg) were added to D-glucono-1,5-lactone (250 mg) and dissolved in 8 equivalents of pyridine (908 μL). After adding 7.5 mL of toluene, the mixture was stirred with a stirrer and the previously prepared behenoyl chloride (C 22 H 43The entire amount of AcOEt (OCl) was added, and the mixture was stirred at room temperature for 1 day under a nitrogen atmosphere. The reaction was monitored by TLC (AcOEt:toluene = 1:20) while stirring for an additional 4 hours at 80 °C. After confirming that the reaction was no longer proceeding, 1 mL of water was added and the mixture was stirred at room temperature for 30 minutes. The reaction mixture was acidified with 6 mL of 2N HCl, and then crystallized with 20 mL of acetone. The resulting crystals were filtered through filter paper and washed with acetone / DMF (4:1). The crystals were purified by silica gel chromatography (toluene) to obtain 403 mg of compound 6 (C22GL) (yield 20%). HMBC-NMR analysis confirmed that compound 6 was the desired five-membered ring compound cyclized by 1-4. TIFF2025131147000016.tif86170

[0028] [Test example] To investigate the thermal properties of C10GL, C12GL, C14GL, C16GL, C18GL, and C22GL, DSC was performed with successive heating-cooling cycles as shown in Table 1. [Table 1]

[0029] Figure 1 shows the DSC curves for step 3 (second cooling) and step 4 (second heating). No change was observed in the DSC curves even after steps 3 and 4 were repeated. All compounds showed an exothermic peak, i.e., a cold crystallization peak, in step 4 (second heating). The exothermic peak (cold crystallization peak) temperatures, i.e., phase change temperatures, for each compound are shown in Table 2. [Table 2]

[0030] It was found that C10GL, C12GL, C14GL, C16GL, C18GL, and C22GL all fall under the category of PCM. From the above measurement results, it can be understood that the phase change temperature increases as the number of carbon atoms in the substituent increases, suggesting that PCMs can be designed according to the desired phase change temperature.

[0031] From the above, it was found that the compound of the present invention can be used as a PCM, which can increase the options for PCMs that can also be used as heat storage materials.

Claims

1. Formula (1): 【Chemical 1】 （１） (R 1 ~R 4 are each independently an acyl group derived from a linear saturated fatty acid having 10 to 22 carbon atoms. Compound.

2. Formula (2): 【Chemistry 2】 （２） (R 1 ~R 4 The definitions are as set forth in claim 1. The compound according to claim 1, represented by:

3. R 1 ~R 4 The compound of claim 1 , wherein all of are the same acyl group.

4. A composition comprising the compound according to any one of claims 1 to 3.

5. A heat storage material comprising the compound according to any one of claims 1 to 3.

6. A method for producing the compound according to any one of claims 1 to 3, comprising the steps of: Formula (3): 【Chemistry 3】 （３） is reacted with a source of an acyl group derived from a linear saturated fatty acid having 10 to 22 carbon atoms to produce a compound of formula (1): 【Chemistry 4】 （１） (R 1 ~R 4 The definitions are as set forth in claim 1. A method of producing a compound of formula (I).

7. The method according to claim 6, wherein the acyl group source comprises at least one selected from the group consisting of an acid halide, an acid anhydride, and an ester of a linear saturated fatty acid having 10 to 22 carbon atoms.

Images