KR101944000B1 - Metal-organic framework for adsorbents of an adsorption chiller and preparation method thereof - Google Patents

Abstract

The present invention relates to a metal organic-structure for an adsorbent of an adsorption refrigerator and a method for producing the same, and more particularly, to a process for preparing NH ₂ -MIL-125 through a precursor of a new Ti (IV) It can be applied as an adsorbent of an adsorption refrigerator excellent in absorption power and hydrothermal stability.

Description

Technical Field [0001] The present invention relates to a metal organic structure for an adsorbent of an adsorption refrigerator, and a method for preparing the same,

The present invention relates to a metal organic-structure for an adsorbent of an adsorption refrigerator and a process for preparing the same, and more particularly, to a process for producing NH ₂ -MIL-125 through a precursor of a new Ti (IV) To an application as an adsorbent.

The consumption of household energy accounts for approximately 20 to 50% of the world's total energy consumption. Air conditioners in buildings that use a significant portion of this energy are traditionally operated by continuous compression by electrical energy. Increased demand for electrical energy by maintaining a high standard of living over time and the emission of carbon dioxide associated with the use of electrical energy will encourage researchers to study higher energy efficiency systems that rely heavily on solar energy for buildings or low temperature industrial waste heat .

Adsorption heat transformation (AHT) systems can provide a technically feasible alternative to compression based air conditioning systems where, in AHT, the working fluid is evaporated, adsorbed by the porous material and then regenerated by low temperature heat. The cold produced by evaporation and the heat blocked by adsorption can be used for cooling and heating, respectively. In such systems, water is preferred as the working fluid due to its high evaporation enthalpy (2440 kJ / kg, 25 ° C) and non-toxic properties. Other fluids that are replaced in these systems are ammonia, ethanol, and methanol. Ideally, the porous adsorbent should be run between a relative humidity range of 0.05 <P / P ₀ <0.35 and have a lower desorption temperature (below 80 ° C). That is, the adsorbent for this thermal conversion system should have a high water absorption capacity at lower average humidity and a lower desorption temperature.

Zeolite and silica gel based systems are commercially available, but there are insufficient problems due to some limitations. For example, zeolites with a strong affinity for water are limited by low water uptake and higher desorption temperatures (up to 300 K). On the other hand, silica gel has low hydrophilicity and low desorption temperature is required for regeneration. However, there is a disadvantage in that the cycle exhibits a low water absorption capacity as a result. These limitations remind the researchers to develop new materials that are more hydrophilic and require lower desorption temperatures for regeneration.

On the other hand, a metal-organic framework (MOF) is a network-structured material assembled by metal ions and organic ligands. Many MOFs have been synthesized and have been studied in a variety of fields such as gas storage / separation, catalysts, adsorption heat conversion and drug delivery. Of these, adsorption heat conversion using metal-organic structures is limited due to hydrothermal sensitivity in water. Some metal-organic structures with high porosity and surface area have been found to have low hydrothermal susceptibility, which hinders their use in air conditioning systems.

Recently, new metal-organic structures with high water stability have been synthesized using arsenic materials such as Zr (IV) and Ti (IV). Because of the rapid water absorption at low relative humidity, NH ₂ -MIL-125 is considered a potential metal-organic structure material in adsorbent-based air conditioning systems. NH ₂ -MIL-125 is composed of basic units of Ti ₈ O ₈ (OH) ₄ - (O ₂ CC ₆ H ₅ -CO ₂ -NH ₂ ) ₆ and 2-aminobenzene dicarboxylic acid (NH ₂ -BDC) (Octamer) connected from a corner or edge share of the TiO ₅ (OH) octahedron, connected by 12 consecutive octamers through a linker (Fig. 1).

Accordingly, the present inventors have focused on the fact that NH ₂ -MIL-125 can be produced through a precursor of a new Ti (IV) and a reaction method and can be applied as an adsorbent of an adsorption refrigerator having a better water adsorption ability The present invention has been completed.

Non-Patent Document 1. Gordeeva et al. Energy 100 (2016): 18-24. Non-Patent Document 2. Dan-Hardi et al. J. Am. Chem. Soc. 131.31 (2009): 10857-10859.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a metal organic structure for an adsorbent of an adsorption refrigerator and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a method for adsorbing a metal adsorbent, comprising the steps of: (a) subjecting a solution containing titanium butoxide, aminobenzene dicarboxylic acid and a solvent to a solvent thermal reaction or reflux reaction; A method for producing an organic structure is provided.

The solvent is selected from the group consisting of dimethylformamide, methyl ethyl ketone, ethanol, diethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, dimethylacetamide, methanol, diethylether, diethylformamide, tetrahydrofuran And a mixture thereof.

The present invention also provides a metal-organic structure for an adsorbent of an adsorption refrigerator produced by the process according to the present invention.

The metal-organic structure may have a crystal domain size of 30 to 80 nm.

The metal-organic structure may have a BET surface area of 1,300 to 1,700 m ² / g.

The metal-organic structure may have micropores of 0.2 to 0.8 cm ³ / g and mesopores of 0.01 to 0.06 cm ³ / g.

According to the present invention, NH ₂ -MIL-125 is prepared through a new precursor of Ti (IV) and a reaction method, and can be applied as an adsorbent of an adsorption refrigerator excellent in water absorption capacity and hydrothermal stability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a crystal structure image of NH ₂ -MIL-125 (Ti) (a) and (b) a polyhedron simplified skeleton image.
2 is a graph showing the results of powder X-ray diffraction (a) of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 2 and Comparative Example 2 of the present invention (PXRD) graph and (b) scanning electron microscope (SEM) images.
3 is a graph showing X-ray diffraction patterns of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 2 and Comparative Example 2 of the present invention (PXRD) data is a close inspection image.
4 is a graph showing the results of powder X-ray diffraction (a) of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 1 and Comparative Example 1 of the present invention (PXRD) graph and (b) scanning electron microscope (SEM) images.
5 is a graph showing the results of powder X-ray diffraction analysis of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 1 of the present invention and Comparative Example 1 (PXRD) data is a close inspection image.
6 is a graph showing nitrogen adsorption isotherms of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 2 and Comparative Example 2 of the present invention.
7 is a graph showing the nitrogen adsorption isotherms of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 1 and Comparative Example 1 of the present invention.
8 is an absorption spectroscopy (UV-Vis) spectrum of NH ₂ -MIL-125 derived from Ti (BuO) ₄ synthesized from Examples 1 and 2 of the present invention.
Figure 9 shows the highest occupied molecular orbital (HOMO) - lowest occupied molecular orbital of NH ₂ -MIL-125 from Ti (BuO) ₄ synthesized from Examples 1 and 2 of the present invention. , LUMO) band gap graph.
10 is a graph showing adsorption isotherms of NH ₂ -MIL-125 (Ti) at 35 ° C.
Figure 11 is NH ₂ -MIL-125 (Ti) of (a) the case of having two amino groups, (b), if having a single amino group and (c) NH ₂ -MIL-125 through the pores in the absence of an amino group ( Ti).
12 is a graph showing the weight change obtained by repeating the adsorption of NH ₂ -MIL-125 (Ti) at 30 ° C and desorption at 80 ° C ten times, and (b) the moisture adsorption amount .
FIG. 13 is a schematic diagram showing a cooling system phenomenon due to water retention and water evaporation due to condensation of water using NH ₂ -MIL-125 (Ti). FIG.

In the following, various aspects and various embodiments of the present invention will be described in more detail.

The present invention provides a process for producing a metal-organic structure for an adsorbent of an adsorption refrigerator, comprising: (a) subjecting a solution containing titanium butoxide, aminobenzene dicarboxylic acid and a solvent to a solvent thermal reaction or a reflux reaction. Specifically, it was confirmed that the characteristics of the metal-organic structure synthesized according to the kind of the titanium precursor were changed, and the metal-organic structure (NH ₂ -MIL-125) synthesized using the titanium precursor titanium isopropoxide, (NH ₂ -MIL-125) synthesized by using titanium butoxide showed excellent water absorption and hydrothermal stability, and it was confirmed to be more suitable as an adsorbent for an adsorption refrigerator.

The solvent is selected from the group consisting of dimethylformamide, methyl ethyl ketone, ethanol, diethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, dimethylacetamide, methanol, diethylether, diethylformamide, tetrahydrofuran And mixtures thereof, but is not limited thereto. Preferably, dimethylformamide can be used.

The reaction may be a solvothermal reaction. In the examples of the present invention, water absorption capacity and hydrothermal stability of a metal-organic structure (NH ₂ -MIL-125) synthesized through a solvent thermal reaction and a reflux reaction were compared. As a result, And the hydrothermal stability and water absorption were improved.

The present invention also provides a metal-organic structure for an adsorbent of an adsorption refrigerator produced by the process according to the present invention.

The metal-organic structure may have a crystal domain size of 30 to 80 nm, preferably 40 to 70 nm, more preferably 50 to 60 nm, and a BET surface area of 1,300 to 1,700 m ² / g, preferably 1400 To 1600 m &lt; ² &gt; / g, and more preferably from 1450 to 1550 m &lt; ² &gt; / g.

In addition, the metal-organic structure may have micropores of 0.2 to 0.8 cm ³ / g and mesopores of 0.01 to 0.06 cm ³ / g.

Hereinafter, production examples and embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

Example 1: Preparation of Ti (BuO) ₄  Originating NH ₂ Synthesis of MIL-125

In order to synthesize a NH ₂ -MIL-125 by the solvothermal reaction, was synthesized NH ₂ -MIL-125 with a little change in the conventional method was reported. NH ₂ -BDC (1.086 g, 6 mmol) was first dissolved in a solution of DMF (3.5 ml) and MeOH (3.5 ml) via sonication in a 25 ml vial. After dissolution was complete, titanium butoxide (Ti (BuO) ₄ ) (0.51 ml, 1.6 mmol) was added and the mixture was sonicated for 5 minutes. The solution was transferred to a Teflon lined bomb and held for 16 hours under an oven at 150 ° C. It was then allowed to cool naturally, and a yellow product was obtained by filtration. After washing with DMF to remove unreacted organic ligand, NH ₂ -MIL-125 derived from Ti (BuO) ₄ was synthesized by washing twice with methanol to replace DMF with methanol.

Example 2: Synthesis of Ti (BuO) ₄  Originating NH ₂ Synthesis of MIL-125

To synthesize NH ₂ -MIL-125 by a refluxing reaction, NH ₂ -BDC (3.85 g, 21.2 mmol) was dissolved in a dry 500 ml round-bottomed flask under an oil bath condition of 1 hour with stirring in anhydrous DMF (50 ml). Thereafter, anhydrous methanol (14 ml) was added, and the mixture was stirred for 1 hour under an oil bath at 100 ° C and refluxing conditions. Then, Ti (BuO) ₄ (4.2 ml, 12.3 mmole) was added to the solution and stirred at 108 ° C under reflux conditions for 72 hours. Thereafter, the reaction product was naturally cooled, and a yellow crystalline reaction product was obtained through filtration. This product was washed twice with DMF to remove excess unreacted ligand and washed twice with methanol to replace DMF with methanol to synthesize NH ₂ -MIL-125 derived from Ti (BuO) ₄ .

Example 3: Preparation of pellets

From Example 1 Ti (BuO) _{4-derived NH 2 NH 2 -BDC (16.29 g} , 89.9 mmol), Ti (BuO) 4 (7.42 ml, 22 mmol), DMF (105 a -MIL-125 in order to mass production ml) and MeOH (105 ml). 4.5 g of the product was mixed with carboxymethylcellulose (CMC, 0.5 g, 1%) and 3.5 ml of water was added dropwise and mixed. Thereafter, it was dried at room temperature for 24 hours and extruded to prepare pellet-shaped NH ₂ -MIL-125.

Comparative Example 1: Synthesis of Ti (iPrO) ₄  Originating NH ₂ Synthesis of MIL-125

But it performed in the same manner as in Example 1, using the titanium isopropoxide (Ti (iPrO) ₄₎ as the titanium precursor was prepared using Ti (iPrO) _4-derived NH ₂ -MIL-125.

Comparative Example 2: Synthesis of Ti (iPrO) ₄  Originating NH ₂ Synthesis of MIL-125

NH ₂ -MIL-125 derived from Ti (iPrO) ₄ was synthesized using titanium isopropoxide as a titanium precursor in the same manner as in Example 2.

All chemicals and solvents were used without any purification, PXRD (powder x-ray diffraction ) profile in the scan rate of 0.5 ° min ^-1, Cu sealed tube Rigaku D / max 2500PC diffractometer having a (λ = 1.54178 Å) (DRUV-Vis) spectra were measured with a SolidSpec-3700 instrument (Shimadzu), and the nitrogen and water adsorption isotherms were measured using a scanning electron microscope (SEM) Volume was measured by ELSORP-MAX and BELSORP-AQUA3 (Bel Japan), respectively. The pore accessibility of NH ₂ -MIL-125 was determined by simulation using Materials Studio program.

2 is a graph showing the results of powder X-ray diffraction (a) of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 2 and Comparative Example 2 of the present invention (PXRD) graph and (b) scanning electron microscope (SEM) images. Referring to FIG. 2, the PXRD profile of all NH ₂ -MIL-125 (Ti) samples was in good agreement with the simulation pattern generated from the reported crystal structure, which proved to be a highly pure two porous material.

3 is a graph showing X-ray diffraction patterns of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 2 and Comparative Example 2 of the present invention (PXRD) data is a close inspection image. Referring to FIG. 3, in a close inspection of the PXRD profile of the NH ₂ -MIL-125 sample, the normalized (101) main peak of the two samples appeared to have different peak width broadening, which correlates with product crystallinity. Also, Ti (BuO) _4-derived sample is Ti (iPrO) I had a peak of a narrow width than the _four-derived sample, which is than the NH _2- MIL-125 synthesized from Ti (BuO) ₄ synthesized from Ti (iPrO) ₄ And has a higher crystallinity. The SEM analysis of these samples (Figure 2b) also confirmed that the samples from Ti (iPrO) ₄ had an irregular shape while the samples from Ti (BuO) ₄ had regular square plate sizes of several hundreds of nm in size, Ti (BuO) _4, the crystal domain size of the resulting sample indicates that the Ti (iPrO) more than ₄ sample derived growth, consistent with the results from the checking PXRD.

4 is a graph showing the results of powder X-ray diffraction (a) of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 1 and Comparative Example 1 of the present invention (PXRD) graph and (b) scanning electron microscope (SEM) images. Referring to FIG. 4, the Ti (BuO) ₄ and Ti (iPrO) ₄ -derived products synthesized by the solvent thermal reaction exhibit higher crystallinity and purity, as shown in the PXRD analysis and peaks, as compared to the reflux reaction. Also, as expected, the solvent thermal reaction with the fixed crystallization process has larger crystal grains than by the reflux reaction. Also, SEM images show that NH ₂ -MIL-125 (Ti) synthesized by solvent thermolysis has a more pronounced crystal form of truncated bipyramid than by the reflux method.

5 is a powder X-ray diffraction analysis (PXRD) of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 1 and Comparative Example 1 of the present invention. ) It is a close inspection image. 5, according to syereo bangjeoksik, the crystal domain size of the sample synthesized by a solvothermal reaction Ti (BuO) ₄ derived from the NH ₂ -MIL-125 and Ti (iPrO) _4-derived NH ₂ -MIL-125 Were about 58 and 43 nm, respectively. Ti (BuO) ₄ is derived from crystal domain size was calculated larger than Ti (iPrO) ₄ resulting crystal domain size. 3, the second embodiment and the comparative crystal domain size calculated of the sample synthesized by a reflux method of Example 2, Ti (BuO) _4-derived NH ₂ -MIL-125 and Ti (iPrO) _4-derived NH ₂ - MIL-125 were about 46 and 27 nm, respectively.

6 is a graph showing nitrogen adsorption isotherms of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 2 and Comparative Example 2 of the present invention.

7 is a graph showing the nitrogen adsorption isotherms of NH ₂ -MIL-125 derived from Ti (BuO) ₄ and NH ₂ -MIL-125 derived from Ti (iPrO) ₄ synthesized from Example 1 and Comparative Example 1 of the present invention. Nitrogen adsorption experiments were carried out at a temperature of 77 K to confirm the specific surface area and pore volume of NH ₂ -MIL-125 (Ti) prepared by the reflux reaction and the solvent thermal reaction.

Table 1 summarizes the BET surface area, total pore volume, micropore volume, and mesopore volume of NH ₂ -MIL-125 (Ti) prepared from Examples 1 and 2 and Comparative Examples 1 and 2 of the present invention .

6 and with reference to Table 1, in the case of a reflux reaction, Ti (BuO) ₄ sample specific surface area (about 1509 m ² / g) was Ti (iPrO) ₄ specific surface area of the resulting sample (about 1358 m ² / g) of . Similarly also solvothermal reaction, Ti (BuO) ₄ specific surface area of the resulting sample (about 1553 m ² / g) is slightly higher than that of Ti (iPrO) ₄ specific surface area of the resulting sample (about 1340 m ² / g). These values are similar to those synthesized by the reflux method. Differences in specific surface area contribute to micropores. That is, Ti by a solvothermal reaction (BuO) ₄ and derived from Ti (iPrO) _4, each derived from 0.6077 cm ³ / g and 0.5312 cm is ³ / g, whereas, Ti by a reflux reaction (BuO) ₄ and derived from Ti (iPrO) _4, respectively 0.5969 and 0.5443 cm ³ / g results.

These properties indicate that, regardless of the synthesis method, NH ₂ -MIL-125 that is There Ti (iPrO) _4, rather than Ti (BuO) ₄ suitable for manufacturing the (Ti). In this case, it is not possible to exclude the possibility that the alkoxy group of the titanium precursor is an important requirement that can affect crystal growth and pore formation when NH ₂ -MIL-125 (Ti) is formed. For example, in the sol-gel reaction of titanium alkoxide, it has been reported that the alkoxy group apparently affects the kinetic of the hydrolysis and condensation reaction, and the effect of the alkoxy group on crystal growth and pore formation is still uncertain. However, the fact that the sample formed using Ti (BuO) ₄ has a higher degree of crystallinity and a regular pore structure allows the nitrogen gas to be easily accessible to the micropores in the sample formed using Ti (BuO) ₄ Lt; / RTI &gt; Therefore, Ti (BuO) ₄ is preferable to Ti (iPrO) ₄ as a precursor regardless of the synthesis method.

Synthesis method Ti (IV) precursor BET surface area
(m ² / g) Total pore volume
(cm ³ / g,
P / P ₀ = 0.990) Micro pore volume (cm ³ / g) Mesopore volume (cm ³ / g) Reflux reaction Ti (BuO) ₄ 1,509 0.6622 0.5969 0.0653 Ti (iPrO) ₄ 1,358 0.5803 0.5443 0.0360 Solvent thermal reaction Ti (BuO) ₄ 1,553 0.6359 0.6077 0.0282 Ti (iPrO) ₄ 1,340 0.5426 0.5312 0.0114

8 is an absorption spectroscopy (UV-Vis) spectrum of NH ₂ -MIL-125 derived from Ti (BuO) ₄ synthesized from Examples 1 and 2 of the present invention. Referring to FIG. 8, the UV / Vis spectra of NH ₂ -MIL-125 synthesized using Ti (BuO) ₄ were different according to the synthesis method.

Figure 9 shows the highest occupied molecular orbital (HOMO) - lowest occupied molecular orbital of NH ₂ -MIL-125 from Ti (BuO) ₄ synthesized from Examples 1 and 2 of the present invention. , LUMO) band gap graph. 9, the HOMO-LUMO bandgap of NH ₂ -MIL-125 derived from Ti (BuO) ₄ , measured by the Kubelka-Munk function from the UV-vis absorption spectrum, was found to be 2.71 eV by the solvent thermal reaction, And 2.75 eV due to the reflux reaction. The NH ₂ -MIL-125 derived from Ti (BuO) ₄ synthesized by the solvent thermal reaction showed a slightly narrower bandgap than that due to the reflux reaction. This narrow band gap to indicate the strong orbital interaction of Ti (IV) and 2-amino-terephthalic-laid (2-amino terephthalate), probably This Ti (BuO) _4-derived NH ₂ -MIL-125 is a high degree of crystallization is produced in . In fact, NH ₂ -MIL-125 synthesized by solvent thermal reaction has larger crystal grains than by the reflux method.

10 is a graph showing adsorption isotherms of NH ₂ -MIL-125 (Ti) at 35 ° C. The water adsorption isotherms of NH ₂ -MIL-125 (Ti) with high surface area and crystallinity synthesized from Ti (BuO) ₄ by solvent thermal reaction were measured by volume measurement at relative pressure. Referring to FIG. 10, NH ₂ -MIL-125 (Ti) shows an S-shaped curve that increases sharply in the range of 0.2 <P / P ₀ <0.3, which is the operating pressure of the adsorption cryogenic chiller. The water adsorption power of NH ₂ -MIL-125 (Ti) at P / P ₀ = 0.3 and 35 ° C is 0.53 g / g which is known to be the highest among the S-shaped isothermal porous materials Value. The S-shaped isotherm can be explained by a pore structure with a narrow neck and a large internal void space. Pores with narrow necks prevent rapid diffusion of water in the initial stage, and then allow rapid water absorption below a certain pressure.

Figure 11 is NH ₂ when having (a) the two amino groups of -MIL-125 (Ti), ( b) NH 2 -MIL-125 through the pores in the case, and (c) if there is no group having a single amino group (Ti). In order to evaluate pore accessibility with water, the window size of NH ₂ -MIL-125 was measured by a modeling program. Referring to FIG. 11, there are three types of pores due to an amino group disorder, and the pore sizes in the absence of two amino groups, one amino group, and amino group are 3.4, 3.8, and 4.2 A, respectively. This is slightly greater than the kinetic diameter of water (2.6 A). As a model study, the water absorption capacity of MIL-125 with the same topology was measured under the same conditions. The water isotherms of MIL-125 also showed similar S-shaped curves due to the pore structure with narrow neck and large voids. Therefore, it can be seen that this type of pore structure has a significant influence on having an S-shaped curve.

FIG. 12 is a graph of the weight change obtained by repeating the adsorption of NH ₂ -MIL-125 (Ti) at 30 ° C and the desorption at 80 ° C ten times, (b) the moisture adsorption amount . Referring to FIG. 12, it can be seen that the moisture adsorption amount of NH ₂ -MIL-125 (Ti) is constant at 45.2% by weight.

As in Example 3, pellets were prepared by mixing 1% carboxymethylcellulose (CMC) as a binder with NH ₂ -MIL-125 in order to obtain a sample of high density in the adsorption cryogenic chiller. The BET surface area and micropore volume of the pellets were 955 m ² / g and 0.3775 cm ³ / g, respectively. These values were lower than the powder samples, but the density of the pellets (0.3 g / ml) was higher than the density of the powder samples (0.27 g / ml). Also, it was confirmed that the water absorption capacity of the pellet had a P / P _{0 of} 0.3 to 0.40 g / g, and that the NH ₂ -MIL-125 pellet had lower water absorption than the powder. In addition, it was confirmed that the water absorption capacity of the pellets was decreased as the amount of CMC increased.

In order to confirm the water stability of NH ₂ -MIL-125, a sample having a high water absorption capacity was injected into 10 cycles of the adsorption / desorption cycle under the temperature condition of adsorption chiller (T _ads = 30 ° C, T _desp = 80 ° C) Respectively. Figure 12 shows that it is stable without a change in the amount of moisture adsorption during the 10-time repeated adsorption / desorption experiments.

Therefore, according to the present invention, it is possible to provide NH ₂ -MIL-125 through a new precursor of Ti (IV) and a reaction method, and can be applied as an adsorbent of an adsorption refrigerator excellent in water absorption ability and hydrothermal stability.

Claims (6)

(a) refluxing a solution comprising titanium butoxide, aminobenzene dicarboxylic acid, and a solvent to produce a metal-organic structure for an adsorbent of an adsorption refrigerator. ◈ Claim 2 is abandoned due to payment of registration fee. The method according to claim 1,
The solvent is selected from the group consisting of dimethylformamide, methyl ethyl ketone, ethanol, diethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, dimethylacetamide, methanol, diethylether, diethylformamide, tetrahydrofuran And mixtures thereof. &Lt; Desc / Clms Page number 24 &gt; 6. A method for producing a metal-organic structure for an adsorbent of an adsorption refrigerator, comprising the steps of: A metal-organic structure for an adsorbent of an adsorption refrigerator produced by the process according to claim 1. The method of claim 3,
Wherein the metal-organic structure has a crystal domain size of 30 to 80 nm. The method of claim 3,
Wherein the metal-organic structure has a BET surface area of 1,300 to 1,700 m ² / g. The method of claim 3,
Wherein the metal-organic structure has micropores of 0.2 to 0.8 cm ³ / g and mesopores of 0.01 to 0.06 cm ³ / g.

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