Ionic compound, absorbent, and absorption device

Abstract

To provide an ionic compound, an absorbent that shows high moisture-absorbing ability and low desorption temperature, and an absorption device.SOLUTION: An ionic compound has a structure represented by the formula (I): ABn, where A is any of the following and where B is any of the following.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to ionic compounds, absorbents, and absorption devices thereof.

Background Art

[0002] Liquid absorbents have several advantages. Liquid absorbents have high hygroscopicity, low regeneration temperature, and low energy consumption. Liquid absorbents are easy to transport and can utilize waste heat over long distances. Therefore, liquid absorbents are widely used in dehumidification systems. Liquid absorbent dehumidification systems are key facilities for reducing carbon emissions and can help improve a company's ESG score in the future.

[0003] A liquid absorbent is a liquid material that can directly absorb water vapor from the air to achieve a dehumidification effect. Its driving force is the difference between the water vapor pressure in the air and the saturated vapor pressure on the surface of the liquid absorbent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional liquid absorbents include aqueous solutions of lithium bromide, lithium chloride, calcium chloride, and magnesium chloride. However, since these salt solutions have strong corrosiveness to metals, they can have a great impact on the reliability and lifespan of the dehumidification system. To avoid corrosion, titanium can be used as the heat exchanger, but this will significantly increase the cost of constructing the dehumidification system. In addition, since conventional salt solutions are prone to crystallization and precipitation when saturated, it will cause a decrease in dehumidification performance and serious maintenance problems of the system, such as clogging of the circulation pump, etc.

[0006] Both the academic and industrial circles have proposed using ionic compounds as liquid absorbents. However, conventional ionic compounds used as liquid absorbents also still have corrosiveness to metals, and their water vapor absorption and desorption capabilities still require improvement.

Means for Solving the Problem

[0007] The present disclosure provides an ionic compound. The ionic compound has a structure represented by formula (I).

[0008] AB n Formula (I)

[0009] In the formula, A is any of the following.

[0010]

Chemical formula

[0011] B is any of the following.

[0012]

Chemical formula

[0013] R 1 、R 2 、R 3 、R 4 、R 5 、およびR 6 are each independently a C 1-6 alkyl group. n is 1 or 2.

[0014] According to an embodiment of the present disclosure, the present disclosure also provides an absorbent. The absorbent contains the ionic compound of the present disclosure.

[0015] According to an embodiment of the present disclosure, the present disclosure also provides an absorption device. The absorption device includes a chamber and the absorbent of the present disclosure, and the absorbent is disposed in the chamber.

Advantages of the Invention

[0016] The present disclosure provides an ionic compound, an absorbent, and an absorption device using the same. According to an embodiment of the present disclosure, the ionic compound is composed of a cationic part A and an anionic part B. The cationic part A may be a quaternary ammonium cationic part derived from 1,4-diazabicyclo[2.2.2]octane, and the anionic part B may be an anionic part derived from alkyl phosphate or alkyl sulfate. Due to the combination of a specific cationic part A and a specific anionic part B, the liquid absorbent using the ionic compound of the present disclosure exhibits higher moisture absorption capacity and lower desorption temperature (desorbable at 60 °C or lower), so the dehumidification efficiency of the absorption device using this absorbent is enhanced. In addition, the liquid absorbent using the ionic compound of the present disclosure has various advantages such as odorless, antibacterial, low corrosiveness, fluidity, and excellent room temperature stability, and thus can be widely applied to various dehumidification devices.

Brief Description of the Drawings

[0017] The present invention can be more fully understood by reading the following detailed description and examples with reference to the accompanying drawings.

Figure 1

Modes for Carrying Out the Invention

[0018] In the following description, the ionic compounds, absorbents, and absorption devices of the present disclosure will be described in detail. In the following detailed description, for the purpose of explanation, numerous specific details and embodiments are presented so that the present disclosure can be better understood. The specific components and configurations described in the following detailed description are presented to clearly illustrate the present disclosure. However, it will be apparent that the exemplary embodiments shown herein are for illustrative purposes only and that the inventive concept can be embodied in various forms without being limited to those exemplary embodiments. Additionally, in the drawings of the different embodiments, similar and / or corresponding components may be indicated using similar and / or corresponding numbers for the purpose of clearly explaining the present disclosure. However, the use of similar and / or corresponding numbers in the drawings of the different embodiments does not imply any correlation between the different embodiments. As used herein, the term "about" in terms of quantity refers to increasing or decreasing an amount that is normal and reasonable to those skilled in the art.

[0019] According to an embodiment of the present disclosure, the present disclosure provides an ionic compound. The ionic compound has a structure represented by formula (I).

[0020] AB n Formula (I)

[0021] In the formula, A may be any of the following.

[0022]

Chemical formula

[0023] B may be any of the following.

[0024]

Chemical formula

[0025] R1 , R 2 , R 3 , R 4 , R 5 , and R 6 is independently H, C 1-6 an alkyl group, and n is 1 or 2.

[0026] According to an embodiment of the present disclosure, the C 1-6 alkyl group may be a straight-chain or branched alkyl group. For example, the C 1-6 alkyl group of the present disclosure may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, pentyl or hexyl. Therefore, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may independently be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, pentyl or hexyl.

[0027] According to an embodiment of the present disclosure, the ionic compound may be composed of a cationic part A and an anionic part B. According to an embodiment of the present disclosure, the cationic part A may be a monovalent quaternary ammonium cationic part derived from 1,4-diazabicyclo[2.2.2]octane, for example, any of the following.

[0028] [Chemical formula]

[0029] In addition, according to an embodiment of the present disclosure, the cationic part A may be a divalent quaternary ammonium cationic part derived from 1,4-diazabicyclo[2.2.2]octane, for example, any of the following.

[0030] [Chemical formula]

[0031] According to an embodiment of the present disclosure, the anion moiety B may be an anion moiety derived from an alkyl phosphate such as any of the following, for example.

[0032]

Chemical formula

[0033] In addition, according to an embodiment of the present disclosure, the anion moiety B may be an anion moiety derived from an alkyl sulfate such as any of the following, for example.

[0034]

Chemical formula

[0035] According to an embodiment of the present disclosure, the ionic compound has a structure represented by formula (I).

[0036] AB n Formula (I)

[0037] In the formula, A may be any of the following.

[0038]

Chemical formula

[0039] B may be any of the following.

[0040]

Chemical formula

[0041] n can be 1. R 1 , R 4 , R 5 , and R 6 may each independently be H, C 1-6 alkyl group.

[0042] For example, the ionic compound of the present disclosure may be any of the following.

[0043]

Chemical formula

[0044] According to an embodiment of the present disclosure, a method for producing an ionic compound having a monovalent quaternary ammonium cation moiety may include the following steps. First, 1,4-diazabicyclo[2.2.2]octane and an anion precursor are mixed to obtain a mixture. According to an embodiment of the present disclosure, the anion precursor is an alkyl phosphate (e.g.,

Chemical formula

Chemical formula

[0045] According to an embodiment of the present disclosure, before performing a heating process on the mixture, the mixture and a solvent are mixed to obtain a solution. According to an embodiment of the present disclosure, the solvent may be toluene, methanol, ethanol, propanol, butanol, ethyl acetate, anisole, butyl acetate, or a combination thereof. According to an embodiment of the present disclosure, the solid content of the solution is from about 5 wt% to 95 wt%, for example 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, or 90 wt%. Here, the solid content means the weight percentage of the components of the solution excluding the solvent with respect to the total weight of the solution.

[0046] According to an embodiment of the present disclosure, the ionic compound has a structure represented by formula (I).

[0047] AB n Formula (I)

[0048] In the formula, A may be the following.

[0049]

Chemical formula

[0050] B may be any of the following.

[0051]

Chemical formula

[0052] n is 2. R 2 、R 3 、R 4 、R 5 、and R 6 may independently be H, C 1-6 alkyl group.

[0053] For example, the ionic compound of the present disclosure may be any of the following.

[0054]

Chemical formula

[0055] According to an embodiment of the present disclosure, a method for producing an ionic compound having a divalent quaternary ammonium cation moiety may include the following steps. First, 1,4-diazabicyclo[2.2.2]octane and an anion precursor are mixed to obtain a mixture. The molar ratio of 1,4-diazabicyclo[2.2.2]octane to the anion precursor is from 1:2 to 1:3 (for example, 1:2.2, 1:2.3, 1:2.4, 1:2.5, or 1:2.8). According to an embodiment of the present disclosure, the anion precursor is an alkyl phosphate (for example [Chemical formula] , wherein R 7 , R 8 , and R 9 may independently be H, C 1-6 alkyl groups. ) or an alkyl sulfate (for example [Chemical formula] , wherein H, R 10 and R 11 may independently be C 1-6 alkyl groups. ). Then, a heating process is performed on the mixture to obtain the ionic compound of the present disclosure. According to an embodiment of the present disclosure, the temperature of the heating process is from about 50°C to 150°C, for example 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or 140°C. According to an embodiment of the present disclosure, the time of the heating process is from 1 hour to 24 hours, for example 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 16 hours, or 20 hours.

[0056] According to an embodiment of the present disclosure, before performing a heating process on a mixture, first the mixture is mixed with a solvent to obtain a solution. According to an embodiment of the present disclosure, the solvent may be toluene, methanol, ethanol, propanol, butanol, ethyl acetate, anisole, butyl acetate, or a combination thereof. According to an embodiment of the present disclosure, the solid content of the solution can be from about 5 wt% to 95 wt%, for example 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, or 80 wt%. Here, the solid content means the weight percentage of the components of the solution excluding the solvent with respect to the total weight of the solution.

[0057] According to an embodiment of the present disclosure, the present disclosure also provides an absorbent. According to an embodiment of the present disclosure, the absorbent may be composed of the ionic compound of the present disclosure.

[0058] According to an embodiment of the present disclosure, the absorbent of the present disclosure contains the ionic compound and the solvent of the present disclosure so that the ionic compound of the present disclosure is uniformly dispersed or dissolved in the solvent. According to an embodiment of the present disclosure, the weight ratio of the ionic compound to the solvent can be from about 1:9 to 9:1, for example, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, or 8:2. According to an embodiment of the present disclosure, the solvent may be water, methanol, ethanol, propanol, butanol, ammonia, or a combination thereof.

[0059] According to an embodiment of the present disclosure, the absorbent of the present disclosure contains an ionic compound and water, and the weight ratio of the ionic compound to water is 4:1. Here, the viscosity of the absorbent can be from 50 cP to 220 cP at 15 °C, for example 60 cP, 80 cP, 100 cP, 120 cP, 150 cP, 180 cP, or 220 cP.

[0060] According to an embodiment of the present disclosure, in the temperature range of 5 °C to 90 °C, the state of the absorbent is liquid, that is, the viscosity of the absorbent is in the range of 10 cP to 1,500 cP.

[0061] According to embodiments of the present disclosure, within a specific temperature range (for example, in the range from 15°C to 50°C, or in the range from 15°C to 60°C), the vapor pressure difference of the absorbent of the present disclosure is relatively large, and the absorbent exhibits high dehumidification efficiency and high desorption capacity at low temperatures.

[0062] According to embodiments of the present disclosure, the present disclosure also provides an absorption device. As shown in the figure, the absorption device 100 may include a chamber 10 and the absorbent 20 of the present disclosure, and the absorbent 20 is disposed in the chamber. According to embodiments of the present disclosure, the chamber may be an absorption chamber, and water vapor is absorbed by the absorbent in the absorption chamber to achieve the purpose of reducing the water vapor content. Since the metal corrosiveness of the absorbent of the present disclosure is extremely low, the installation cost of the absorption device can be reduced. Further, since the absorbent of the present disclosure is a fluid in the temperature range from 5°C to 90°C, it is suitable for use in an absorption device employing a spray or liquid flow process.

[0063] Exemplary embodiments will be described in detail below with reference to the accompanying drawings so as to be easily understood by those of ordinary skill in the art. The inventive concept can be embodied in various forms without being limited to the exemplary embodiments shown herein. Descriptions of well-known parts are omitted, and like reference numerals denote like components throughout.

Examples

[0064] Preparation of Ionic Compound (1)

[0065] Example 1 Trimethyl phosphate (0.20 mol) and 1,4-diazabicyclo[2.2.2]octane (0.20 mol) were placed in a reaction flask, and toluene (60 mL) (used as a solvent) was added to the reaction flask. After heating at 100 °C for 12 hours, the reaction flask was cooled to room temperature, and the obtained solid was collected. Then, the obtained solid was dissolved in water (50 mL), and water and toluene were removed by a rotary concentrator. Then, the obtained product was subjected to a lyophilization process to obtain an ionic compound (1) (having the following structure.) (white solid, yield 98%)

[0066]

Chem.

[0067] The synthetic route of the above reaction was as follows.

[0068]

Chem.

[0069] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (1) are shown below. 1 H NMR (400 MHz, ppm, CD3OD): δ 3.50 (d, J = 8.4 Hz, 6H), 3.354 (t, J = 6.0 Hz, 6H), 3.20 (t, J = 6.0 Hz, 6H), 3.04 (s, 3H)

[0070] Example 2 Trimethyl phosphate (0.84 mol) and 1,4-diazabicyclo[2.2.2]octane (0.8 mol) were placed in a reaction flask, and 1-butanol (n-BuOH) (50 mL) (used as a solvent) was added to the reaction flask. After heating at 60 °C for 12 hours, the reaction flask was cooled to room temperature. Then, 1-butanol was removed by a rotary concentrator. Then, the obtained product was placed in a vacuum oven and baked at 110 °C for 12 hours to obtain an ionic compound (1) (white solid, yield 98%). The synthetic route of the above reaction was as follows.

[0071]

Chem.

[0072] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (1) are shown below. 1 H NMR(400MHz, ppm, CD3OD): δ 3.50 (d, J = 8.4Hz, 6H), 3.354 (t, J = 6.0Hz, 6H), 3.20 (t, J = 6.0Hz, 6H), 3.04 (s, 3H)

[0073] Preparation of the ionic compound (2)

[0074] Example 3 Trimethyl phosphate (0.22 mol) and 1,4-diazabicyclo[2.2.2]octane (0.10 mol) were placed in a reaction flask, and toluene (40 mL) (used as a solvent) was added to the reaction flask. After heating at 100 °C for 12 hours, the reaction flask was cooled to room temperature, and the obtained solid was collected. Next, the obtained solid was dissolved in water (50 mL), and water and toluene were removed by a rotary concentration device. Then, the obtained product was subjected to a freeze-drying process to obtain the ionic compound (2) (having the following structure.) (white solid, yield 92%)

[0075]

Chem.

[0076] The synthetic route of the above reaction was as follows.

[0077]

Chem.

[0078] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (2) are shown below. 1 H NMR(400MHz, ppm, CD3OD): δ 4.02 (s, 12H), 3.58 (s, 6H), 3.56 (s, 6H), 3.36 (s, 6H)

[0079] Example 4 Trimethyl phosphate (0.44 mol) and 1,4-diazabicyclo[2.2.2]octane (0.2 mol) were placed in a reaction flask, and 1-butanol (n-BuOH) (50 mL) (used as a solvent) was added to the reaction flask. After heating at 60 °C for 12 hours, the reaction flask was cooled to room temperature. Then, 1-butanol was removed by a rotary evaporator. Next, the obtained product was placed in a vacuum oven and baked at 110 °C for 12 hours to obtain an ionic compound (2) (white solid, yield 98%). The synthetic route of the above reaction was as follows.

[0080]

Chemical formula

[0081] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (2) are shown below. 1 H NMR (400 MHz, ppm, CD3OD): δ 4.02 (s, 12H), 3.58 (s, 6H), 3.56 (s, 6H), 3.36 (s, 6H)

[0082] Preparation of ionic compound (3)

[0083] Example 5 Triethyl phosphate (0.2 mol) and 1,4-diazabicyclo[2.2.2]octane (0.2 mol) were placed in a reaction flask, and toluene (60 mL) (used as a solvent) was added to the reaction flask. After heating at 100 °C for 12 hours, the reaction flask was cooled to room temperature, and the lower layer liquid was collected. Then, the obtained lower layer liquid was dissolved in water (100 mL). After extracting three times with diethyl ether (60 mL), the aqueous phase was collected, and activated carbon (1 g) was added. After heating at 50 °C for 4 hours, the obtained product was filtered. Then, the filtrate was concentrated, dehydrated, and subjected to a freeze-drying process to obtain an ionic compound (3) (having the following structure) (pale yellow liquid, yield 93%).

[0084]

Chem.

[0085] The synthesis route of the above reaction was as follows.

[0086]

Chem.

[0087] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (3) are shown below. 1 H NMR(400MHz,ppm,CD3OD):δ3.94 - 3.82(m,4H),3.31 - 3.27(m,8H),3.18 - 3.14(m,6H),1.32(t,J = 5.6Hz,3H),1.21(t,J = 5.6Hz,6H)

[0088] Example 6 Triethyl phosphate (0.42 mol) and 1,4-diazabicyclo[2.2.2]octane (0.4 mol) were placed in a reaction flask, and 1-butanol (n-BuOH) (40 mL) (used as a solvent) was added to the reaction flask. After heating at 100 °C for 12 hours, the reaction flask was cooled to room temperature. Then, extraction was performed 3 times with ethyl acetate (50 mL), the lower layer liquid was collected, and the solvent was removed using a rotary evaporator. Next, the obtained product was placed in a vacuum oven and baked at 110 °C for 12 hours to obtain the ionic compound (3) (pale yellow liquid, yield 92%). The synthesis route of the above reaction was as follows.

[0089]

Chem.

[0090] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (3) are shown below. 11H NMR (400 MHz, ppm, CD3OD): δ 3.94 - 3.82 (m, 4H), 3.31 - 3.27 (m, 8H), 3.18 - 3.14 (m, 6H), 1.32 (t, J = 5.6 Hz, 3H), 1.21 (t, J = 5.6 Hz, 6H)

[0091] Preparation of Ionic Compound (4)

[0092] Example 7 Triethyl phosphate (0.25 mol) and 1,4-diazabicyclo[2.2.2]octane (0.1 mol) were placed in a reaction flask, and toluene (40 mL) (used as a solvent) was added to the reaction flask. After heating at 100 °C for 12 hours, the reaction flask was cooled to room temperature, and the lower layer liquid was collected. Then, the lower layer liquid was dissolved in water (80 mL). After extracting three times with diethyl ether (50 mL), the aqueous phase was collected, and activated carbon (1 g) was added. After heating at 50 °C for 4 hours, the resulting product was filtered. Then, the filtrate was concentrated, dehydrated, and subjected to a freeze-drying process to obtain ionic compound (4) (having the following structure) (pale yellow liquid, yield 90%).

[0093]

Chemical Structure

[0094] The synthetic route of the above reaction was as follows.

[0095]

Chemical Structure

[0096] The measurement results of the nuclear magnetic resonance spectrum of ionic compound (4) are shown below. 1 1H NMR (400 MHz, ppm, CD3OD): δ 3.95 (s, 12H), 3.88 (quint, J = 5.6 Hz, 8H), 3.64 (q, J = 5.6 Hz, 4H), 1.43 (t, J = 5.6 Hz, 6H), 1.23 (t, J = 5.6 Hz, 12H).

[0097] Example 8 Triethyl phosphate (0.25 mol) and 1,4-diazabicyclo[2.2.2]octane (0.1 mol) were placed in a reaction flask, and 1-butanol (n-BuOH) (20 mL) (used as a solvent) was added to the reaction flask. After heating at 140 °C for 12 hours, the reaction flask was cooled to room temperature. Then, extraction was performed three times using ethyl acetate (40 mL), the lower layer liquid was collected, and the solvent was removed using a rotary evaporation device. Next, the obtained product was placed in a vacuum oven and baked at 110 °C for 12 hours to obtain an ionic compound (4) (pale yellow liquid, yield 92%). The synthetic route of the above reaction was as follows.

[0098]

Chemical formula

[0099] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (4) are shown below. 1 H NMR (400 MHz, ppm, CD3OD): δ 3.95 (s, 12H), 3.88 (quint, J = 5.6 Hz, 8H), 3.64 (q, J = 5.6 Hz, 4H), 1.43 (t, J = 5.6 Hz, 6H), 1.23 (t, J = 5.6 Hz, 12H)

[0100] Comparative Example 1 Triethyl phosphate (0.3 mol) and 1-methylimidazole (0.3 mol) were placed in a reaction flask. After heating at 140 °C for 12 hours, the reaction flask was cooled to room temperature, and the obtained product was dissolved in water (80 mL). After extraction three times using diethyl ether (50 mL), the aqueous phase was collected, and activated carbon (1 g) was added. After heating at 50 °C for 4 hours, the obtained product was filtered. Next, the filtrate was concentrated, dehydrated, and subjected to a freeze-drying process to obtain an ionic compound (5) (having the following structure) (pale yellow liquid, yield 90%).

[0101]

Chemical formula

[0102] The synthetic route of the above reaction was as follows.

[0103]

Chemical formula

[0104] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (5) are shown below. 1 H NMR(400MHz,ppm,CD3OD):δ8.95(s,1H),7.66(s,1H),7.59(s,1H),4.27(q,J=6.0Hz,2H),3.94(s,3H),3.91(quint,J=5.6Hz,4H),1.55(t,J=6.0Hz,3H),2.26(t,J=5.6Hz,6H)

[0105] Comparative Example 2 2-(N,N-dimethylamino)ethanol (DMAE) (0.1 mol) was placed in a reaction flask. Subsequently, trimethyl phosphate (0.1 mol) was added dropwise to the reaction flask. After heating at 55 °C for 24 hours, the reaction flask was cooled to room temperature to obtain a white solid. The solid was dissolved in water (50 mL). After extracting three times with diethyl ether (30 mL), the aqueous phase was collected. After dehydration using a rotary evaporator, the obtained product was placed in a vacuum oven at 60 °C for 12 hours to obtain an ionic compound (6) (having the following structure) (pale yellow liquid, yield 92%).

[0106]

Chemical formula

[0107] The synthetic route of the above reaction was as follows.

[0108]

Chemical formula

[0109] The measurement results of the nuclear magnetic resonance spectrum of the ionic compound (6) are shown below. 11H NMR (400 MHz, ppm, CD3OD): δ 3.99 - 3.96 (m, 2H), 3.55 (s, 3H), 3.53 (s, 3H), 3.48 - 3.46 (m, 2H), 3.20 (s, 9H)

[0110] Preparation of the absorbent

[0111] Example 9 The ionic compound (1) and water were mixed. The weight ratio of the ionic compound (1) to water was 4:1. After stirring uniformly, the absorbent (1) was obtained.

[0112] Examples 10 - 12 Examples 10 - 12 were carried out in the same manner as Example 9, except that the ionic compound (1) was replaced with ionic compounds (2) - (4) respectively, to obtain absorbents (2) - (4).

[0113] Comparative Examples 3 and 4 Comparative Examples 3 and 4 were carried out in the same manner as Example 9, except that the ionic compound (1) was replaced with ionic compounds (5) and (6) respectively, to obtain absorbents (5) and (6).

[0114] Comparative Example 5 The ionic compound (7) (having the following structure) was prepared. The ionic compound (7) and water were mixed. The weight ratio of the ionic compound (7) to water was 4:1. After stirring uniformly, the absorbent (7) was obtained.

[0115]

Chemical formula

[0116] Comparative Example 6 The ionic compound (8) (having the following structure) was prepared. The ionic compound (8) and water were mixed. The weight ratio of the ionic compound (8) to water was 4:1. After stirring uniformly, the absorbent (8) was obtained.

[0117]

Chemical formula

[0118] Comparative Example 7 An ionic compound (9) (having the following structure) was prepared. The ionic compound (9) and water were mixed. The weight ratio of the ionic compound (9) to water was 4:1. After uniformly stirring, absorbent (9) was obtained.

[0119]

Chemical formula

[0120] Comparative Example 8 Lithium chloride (LiCl) was prepared. Lithium chloride and water were mixed. The weight ratio of lithium chloride to water was 1:2. After uniformly stirring, absorbent (10) was obtained.

[0121] Measurement of water vapor pressure The water vapor pressures of absorbents (1) to (4) were measured at 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, and 60°C, and the vapor pressure differences of absorbents (1) to (4) at each temperature were determined. The results are shown in Table 1. Further, the water vapor pressures of absorbents (5) to (10) were measured at 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, and 60°C, and the vapor pressure differences of absorbents (5) to (10) at each temperature were determined. The results are shown in Table 2.

[0122] The method for measuring the vapor pressure of the absorbent used the melting-point model (reference: J. Chem. Eng. Data 2004, 49, 1550 - 1553) and included the following steps. The absorbent was placed in a container and cooled to 5°C. Vacuum was applied until the evaporation of water vapor began, and then the vacuum system was switched off and the container was heated. The vapor pressure was measured every 5°C using a pressure gauge (EJX310A, YOKOGAWA).

[0123]

Table 1

[0124]

Table 2

[0125] The measured water vapor pressure of the absorbent (10) (lithium chloride aqueous solution) of the present disclosure is consistent with the values reported in the relevant literature (Applied Thermal Engineering 2017, 124, 271-278).

[0126] The dehumidifying ability of the absorbent can be evaluated by its water vapor pressure. When the absorbent operates in an absorption device, it absorbs water vapor from the surrounding environment to reduce humidity, which is driven by the difference between the water vapor pressure in the air and the saturated vapor pressure on the surface of the absorbent. The minimum relative humidity of air dehumidification by the absorbent can be evaluated based on the water vapor pressure of the absorbent. The lower the water vapor pressure of the absorbent, the stronger the moisture absorption ability of the absorbent (i.e., the ionic compound aqueous solution) at a specific temperature.

[0127] As shown in Table 1, it was observed that the absorbent made from the ionic compound of the present disclosure has a water vapor pressure of 1.1 kPa or less at 5 to 20 °C.

[0128] In addition, the lower the water vapor pressure, the stronger the affinity for water (the more difficult it is to desorb water), and the water vapor pressure increases with the increase in temperature. Therefore, the absorbent is more excellent in the ability to absorb and desorb water within a specific temperature range as the vapor pressure difference within the specific temperature range is larger (i.e., the dehumidifying ability is higher). Therefore, when the absorbent shows a larger vapor pressure difference within a specific temperature range, its dehumidification efficiency is higher (i.e., the dehumidifying ability of the absorbent is higher).

[0129] As shown in Table 2, the lithium chloride aqueous solution has a low water vapor pressure at low temperatures (i.e., good water affinity), but the vapor pressure difference (Vp 60-15) is low. This indicates that the lithium chloride aqueous solution retains water vapor even at 60 °C, and further heating to a higher temperature is required for effective desorption, resulting in an increase in energy consumption for absorbent regeneration.

[0130] As shown in Tables 1 and 2, the absorbents prepared from the ionic compounds of the present disclosure (i.e., absorbents (1) to (4)) have a larger vapor pressure difference between 15 °C and 50 °C (Vp 50-15 ), and between 15 °C and 60 °C (Vp 60-15 ) compared to the lithium chloride aqueous solution (absorbent (10)). Therefore, the ionic compounds of the present disclosure have the potential to reduce the energy consumption required for absorbent regeneration and increase the dehumidification efficiency of the absorbent.

[0131] Corrosion test Copper foil (C1100P) (size 10 × 10 × 2 mm 3 ) was prepared and weighed. Then, the copper foil was placed in sample vials containing each absorbent (i.e., absorbents (1) to (10)) (8 mL) and tap water, respectively. After stirring at 80 °C for 2 days, the copper foil was taken out, dried, weighed, and the weight increase / decrease rate of the copper foil was determined. The results are shown in Table 3. Then, the copper foil was replaced with aluminum foil (A5052) (size 10 × 10 × 2 mm 3 ) and stainless steel foil (SUS304) (size 10 × 10 × 2 mm 3 ), and the above steps were repeated. The results are shown in Table 3.

[0132]

Table 3

[0133] As shown in FIG. 3, lithium chloride and absorbents (5) to (10) exhibit different degrees of corrosiveness with respect to stainless steel foil, aluminum foil, and copper foil. Further, according to Table 3, absorbents (absorbents (1) to (4)) made from the ionic compounds of the present disclosure exhibit minimal corrosiveness with respect to stainless steel foil and aluminum foil, and also exhibit lower corrosiveness with respect to copper foil.

[0134] Viscosity measurement The viscosities of absorbents (1) to (4) at each temperature were measured with a viscometer (DV-II+Pro, Brookfield). The results are shown in Table 4.

[0135]

Table 4

[0136] Viscosity is also an important parameter for evaluating absorbents. If the viscosity of the absorbent is too low, liquid carryover occurs, and it becomes easy for the liquid to be entrained in the air and carried out, resulting in environmental pollution. On the other hand, if the viscosity of the absorbent is too high, the fluidity of the absorbent decreases, and the energy consumption of the pump increases. As shown in Table 4, the absorbents made from the ionic compounds of the present disclosure have viscosities at 15°C of 50 cP to 220 cP, and are suitable for use in a dehumidification system employing a spray or liquid flow process.

[0137] Odor and decomposition evaluation Since the air drawn in by the dehumidification system comes into direct contact with the absorbent, it can be said that if the ionic compound produces an odor, it is not suitable for use in an air conditioning system. Absorbents (1) to (4) made from the ionic compounds of the present disclosure were stored at room temperature and normal pressure for 180 days. And when the evaluation was carried out, absorbents (1) to (4) did not undergo degradation and did not produce any objectionable odor.

[0138] In summary, the absorbent containing the ionic compound of the present disclosure has a higher moisture absorption capacity and a lower desorption temperature, so the dehumidification efficiency of the absorption device using this absorbent is improved. In addition, the liquid absorbent containing the ionic compound of the present disclosure provides advantages such as odorlessness, antibacterial property, low corrosiveness, fluidity, and excellent room temperature stability, and thus can be widely applied to various dehumidification devices.

[0139] It will be apparent that various modifications and changes can be made to the disclosed methods and substances. The specification and examples are intended to be regarded merely as illustrative, and the true scope of the present disclosure is indicated by the following claims and their equivalents.

Explanation of Signs

[0140] 10…Chamber 20…Absorbent 100…Absorption device

Claims

1. An ionic compound having a structure represented by formula (I). AB ｎ Formula (I) (In the formula, A is any of the following.) 【Chemical 1】 B is as follows. 【Chemical 2】 R １ , R ２ , R ３ , R ４ , and R ５ are independently C1-6 alkyl groups, and n is 1 or 2.)

2. The ionic compound according to claim 1, wherein A is any of the following. [Chemical Formula 3]

3. The ionic compound according to claim 1, wherein B is any of the following. 【Chemical Formula 4】

4. A is as follows, 【Chemical Formula 5】 B is as follows [[Chemical Formula 6]] n is 1, and R １ , R ４ , and R ５ are independently C １－６ alkyl groups, the ionic compound according to claim 1.

5. A is as follows, 【Chemical Formula 7】 B is as follows, 【Chemical 8】 n is 2, and R ２ , R ３ , R ４ , and R ５ are independently C １－６ alkyl groups, the ionic compound according to claim 1.

6. An absorbent containing an ionic compound, wherein the ionic compound is the ionic compound according to any one of claims 1 to 5.

7. Further comprising a solvent, The absorbent according to claim 6, wherein the weight ratio of the ionic compound to the solvent is from 1:9 to 9:

1.

8. A chamber, An absorbent disposed in the chamber, An absorption device comprising: The absorption device, wherein the absorbent is the absorbent according to claim 6.

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