CN113024834A

CN113024834A - DUT-67 and batch preparation method and application thereof

Info

Publication number: CN113024834A
Application number: CN202110302619.8A
Authority: CN
Inventors: 李松; 夏潇潇; 涂正凯; 蔡姗姗; 刘治鲁
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2021-03-22
Filing date: 2021-03-22
Publication date: 2021-06-25

Abstract

The invention belongs to the technical field related to preparation and application of porous materials, and discloses a DUT-67 and a batch preparation method and application thereof, wherein the method comprises the following steps: s1: dissolving metal salt and an organic ligand in a solvent to obtain a mixed solution, wherein the molar ratio of the organic ligand to the metal salt to the solvent is 1: 2: 100-1: 4: 400; s2: adding a regulator into the mixed solution, wherein the regulator is an alkaline regulator; s3: and heating the solution obtained in the step S2 to enable the metal salt and the organic ligand to react to obtain the DUT-67, wherein the heating temperature is 60-100 ℃. The method has the advantages of obviously shortening the preparation time of the DUT-67, improving the yield and reducing the energy required by the reaction.

Description

DUT-67 and batch preparation method and application thereof

Technical Field

The invention belongs to the technical field related to preparation and application of porous materials, and particularly relates to a DUT-67 and a batch preparation method and application thereof.

Background

The metal organic framework material is a porous material formed by self-assembling metal ions or metal clusters and organic ligands, has the advantages of high specific surface area, large pore volume, adjustable structure and the like, and has wide application prospect in the fields of adsorption refrigeration, gas storage, photoelectricity, catalysis and the like. DUT-67 is a zirconium-based metal organic framework material with high specific surface area and pore volume. In addition, DUT-67 also has good chemical and thermal stability.

The DUT-67 as a novel adsorbent has good application prospect in an adsorption refrigeration system, and the adsorption refrigeration performance of the adsorbent is far better than that of the traditional adsorbents such as zeolite, silica gel and active carbon. In the prior art, the DUT-67 is prepared by dissolving a metal salt in a solvent, performing ultrasonic treatment for 10 minutes, adding an organic ligand, performing ultrasonic treatment for 5 minutes, adding a glacial acetic acid regulator, performing ultrasonic treatment for 10 minutes, and then putting the mixture into a reaction vessel for high-temperature reaction, wherein ultrasonic treatment is required in each step of the method to occupy a lot of time, single reaction requires 48 hours to obtain a target product, the yield is low, each reaction only can obtain 200-300 mg of DUT-67, the reaction needs to be performed at high temperature and high pressure, the reaction temperature is above 120 ℃, the reaction needs to be performed in a closed vessel, and the pressure in the heated vessel is higher than the normal pressure, so that the industrial production and application of the DUT-67 are greatly reduced.

In view of the above technical problems, it is highly desirable to design a new method for mass production of DUT-67 to solve the technical problems of long reaction time, low yield, and high energy required for reaction in the prior art.

Disclosure of Invention

In view of the above drawbacks or needs for improvement in the prior art, the present invention provides a DUT-67, a batch manufacturing method and applications thereof, so as to solve the technical problems of long manufacturing time, low yield, high reaction energy requirement, and inability to perform industrial production and applications in the prior art.

To achieve the above object, according to one aspect of the present invention, there is provided a method of batch manufacturing DUTs-67, the method comprising: s1: dissolving metal salt and an organic ligand in a solvent to obtain a mixed solution, wherein the molar ratio of the organic ligand to the metal salt to the solvent is 1: 2: 100-1: 4: 400; s2: adding a regulator into the mixed solution, wherein the regulator is an alkaline regulator; s3: and heating the solution obtained in the step S2 to enable the metal salt and the organic ligand to perform a coordination reaction to obtain the DUT-67, wherein the heating temperature is 60-100 ℃.

Preferably, the alkaline regulator is one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide and ammonia water.

Preferably, the molar concentration ratio of the alkaline regulator to the solvent is 1: 55-1: 170.

Preferably, the metal salt is a zirconium metal salt.

Preferably, the molar ratio of the organic ligand, metal salt and solvent is 1: 3: 225.

Preferably, the step S3 further includes washing the obtained DUT-67, and then drying it firstly under the atmospheric pressure of 60-80 ℃ and then under the vacuum of 100-150 ℃.

According to another aspect of the present invention, there is provided a DUT-67 manufactured by the above method of manufacturing DUTs-67 in batches.

According to yet another aspect of the present invention, there is provided a use of the DUT-67 described above in a sorption refrigeration system.

In general, compared with the prior art, the DUT-67 and the batch preparation method and application thereof provided by the invention have at least the following advantages:

1. the regulator can reduce the activation energy of the reaction, so that more molecules become activated molecules, and further, the reaction can obtain higher reaction rate at the temperature of lower than 100 ℃ and under the normal pressure, the reaction condition is reduced, and the reaction efficiency is improved.

2. The regulator is an alkaline regulator, the organic ligand is acidic after being dissolved, the solubility of the organic ligand can be reduced by adding the acidic regulator, the reaction is limited to milligram level, and the DUT-67 can not be prepared in large batch, the alkaline regulator can effectively increase the solubility of the organic ligand and increase the effective collision of reactant molecules, and the reactant molecules after the effective collision are combined together to form crystal nuclei, so that the nucleation probability of crystals is increased, and the DUT-67 can be prepared in large batch; meanwhile, the regulator can enable metal salts and the like to form a hydration state in the solution, so that the entropy of the solution is reduced, the growth driving force of crystals is reduced, and the growth of the crystals is facilitated.

3. The mol ratio of the organic ligand, the metal salt and the solvent is controlled to be 1: 2: 100-1: 4: 400, and the coordination number of the metal salt is higher than that of the organic ligand in the ratio, so that the concentration of the active sites can be effectively improved, the reaction is facilitated, and unnecessary waste of reactants is avoided.

4. The molar concentration ratio of the alkaline regulator to the solvent is 1: 55-1: 170, so that the activation energy of the reaction can be effectively reduced, and the pH value of the solution can not be obviously changed, so that the normal operation of the reaction can not be influenced.

5. The alkaline regulator is adopted and the appropriate concentration ratio is guaranteed, so that the reaction can be carried out at a lower temperature, and meanwhile, the metal salt and the organic ligand can be dissolved and reacted while being dissolved without being completely dissolved, so that the time is saved without ultrasonic treatment compared with the prior art.

Drawings

FIG. 1 shows a method step diagram for batch manufacturing of DUTs-67 according to an embodiment of the present disclosure;

FIG. 2 shows an X-ray diffraction pattern of DUT-67 obtained in example 1 of the present disclosure;

FIG. 3 shows a graph of nitrogen desorption of DUT-67 obtained in example 1 of the present disclosure at a temperature of 77K;

FIG. 4 shows an aperture profile of a DUT-67 obtained in example 1 of the present disclosure;

FIG. 5 shows a scanning electron microscope image of DUT-67 obtained by embodiment 1 of the present disclosure;

FIG. 6 shows an X-ray diffraction pattern of DUT-67 obtained in example 5 of the present disclosure;

FIG. 7 shows a graph of nitrogen desorption at a temperature of 77K for the DUT-67 obtained in example 5 of the present disclosure;

FIG. 8 shows an aperture profile of a DUT-67 obtained by embodiment 5 of the present disclosure;

FIG. 9 shows a scanning electron microscope image of DUT-67 obtained by embodiment 5 of the present disclosure;

FIG. 10 shows an X-ray diffraction pattern of DUT-67 obtained in example 4 of the present disclosure;

FIG. 11 shows a graph of nitrogen desorption at a temperature of 77K for the DUT-67 obtained in example 4 of the present disclosure;

FIG. 12 shows an aperture profile of a DUT-67 obtained in embodiment 4 of the present disclosure;

FIG. 13 shows a scanning electron microscope image of DUT-67 obtained by embodiment 4 of the present disclosure;

FIG. 14 shows an X-ray diffraction pattern of a prior art DUT-67;

FIG. 15 shows a graph of nitrogen desorption at a temperature of 77K for a prior art DUT-67;

FIG. 16 shows a prior art resulting aperture profile of a DUT-67;

FIG. 17 shows the water vapor adsorption curve of DUT-67 obtained in example 4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to FIG. 1, the present invention provides a method for batch manufacturing of DUTs-67, including the following steps S1-S3.

S1: dissolving metal salt and an organic ligand in a solvent to obtain a mixed solution, wherein the molar ratio of the organic ligand to the metal salt to the solvent is 1: 2: 100-1: 4: 400.

In this embodiment, first, the metal salt is dissolved in a certain amount of solvent, and the metal salt is completely dissolved by stirring to obtain a uniform metal salt solution. Then adding a proper amount of organic ligand, stirring and mixing.

Wherein the metal salt is zirconium metal salt such as zirconium tetrachloride and zirconium oxychloride. The solvent is deionized water, ethanol, N-dimethylacetamide, N-methylpyrrolidone, N-diethylformamide and the like. The molar ratio of the organic ligand to the metal salt to the solvent is 1: 2: 100-1: 4: 400. The coordination number of the metal salt is higher than that of the organic ligand in the proportion, so that the concentration of the activation site can be effectively improved, the reaction is facilitated, and meanwhile, unnecessary waste of reactants is avoided. The concentration of the metal salt is higher, so that the concentration of the activated molecules is improved, the effective collision is increased, and the reaction rate is favorably improved; meanwhile, the concentration of the metal salt is higher than the saturated concentration, so that the metal salt cannot be completely dissolved, and the concentration of the metal salt can also influence the pH value of the solution and further influence the dissolution of the organic ligand. The preferred stirring speed is 300-1000 rpm, and the stirring time is 10-30 min.

S2: adding a regulator into the mixed solution, wherein the regulator is an alkaline regulator.

The alkaline regulator is preferably one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide and ammonia water, and in the case of sodium hydroxide and potassium hydroxide, the concentration is preferably 1 mol/L.

The molar concentration ratio of the alkaline regulator to the solvent is 1: 55-1: 170, so that the activation energy of the reaction can be effectively reduced, and the pH value of the solution can not be obviously changed, so that the normal operation of the reaction can not be influenced.

The regulator can reduce the activation energy of the reaction, so that more molecules become activated molecules, and the reaction efficiency can be improved. The organic ligand is acidic after being dissolved, the solubility of the organic ligand can be reduced by adding the acidic organic ligand, the reaction is limited to milligram level, the DUT-67 can not be prepared in large batch, the solubility of the organic ligand can be effectively increased by the alkaline regulator, the effective collision of reactant molecules is increased, the reactant molecules after effective collision are combined together to form crystal nuclei, and the probability of crystal nucleation is increased, so the DUT-67 can be prepared in large batch; meanwhile, the regulator can enable metal salts and the like to form a hydration state in the solution, and the entropy of the solution is reduced, so that the growth driving force of the crystal is reduced, and the growth of the crystal is facilitated.

S3: and heating the solution obtained in the step S2 to enable the metal salt and the organic ligand to react to obtain the DUT-67, wherein the heating temperature is 60-100 ℃.

The stirring speed in this step may be 300 to 1000 rpm. The alkaline regulator reduces the activation energy of the reaction, and simultaneously can increase the solvent degree of the organic ligand so as to promote the reaction, so that the reaction of the metal salt and the organic ligand can be carried out at low temperature and normal pressure. The heating temperature is 60-100 ℃, the reaction time is 2-6 hours, and the reaction pressure is normal pressure.

And separating the reacted solution to obtain a solid product, and carrying out aftertreatment on the solid product to obtain the DUT-67.

And naturally cooling the reacted solution to room temperature, separating the generated solid product from the reaction mother liquor, washing impurities in the solid by adopting a certain amount of solvent or solution, and drying the solid to obtain the required DUT-67.

The solid product can be separated from the reaction mother liquor by centrifugation or filtration. The solvent or solution used for removing impurities is ethanol, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone, N-diethylformamide, sodium acetate solution, sodium formate solution, sodium carbonate solution, sodium bicarbonate solution, etc.

The drying treatment in this step includes drying under normal pressure and then drying under vacuum. The drying temperature under normal pressure is 60-80 ℃, and the drying time under normal pressure is 6-12 hours. The vacuum drying pressure is less than 150Pa, the vacuum drying temperature is 100-150 ℃, and the vacuum drying time is 6-12 hours.

Through the above treatment, the ratio of each reactant, solvent and solution is controlled within the above range, and parameters such as the speed, time, temperature and the like of stirring, centrifuging and drying treatment are adjusted within the above range, so that the reaction can be carried out under normal pressure, the preparation time of the DUT-67 is effectively shortened, and the yield of the DUT-67 is improved.

In another aspect, the present application provides a DUT-67 that is fabricated using the above method for batch fabrication of DUTs-67.

In yet another aspect, the present application provides for the use of the DUT-67 described above, with the DUT-67 being particularly useful in adsorption refrigeration systems.

Example 1

The metal salt in this example is zirconium tetrachloride.

(1) Firstly, dissolving 81.60mmol of zirconium tetrachloride into 4.08mol of ethanol, and stirring at the speed of 300rpm for 10min to completely dissolve the zirconium tetrachloride to obtain a uniform solution;

(2) 40.80mmol of organic ligand is added into the solution, and the solution is stirred for 10min at the rotating speed of 300rpm to be mixed uniformly.

(3) Then adding 24.00mmol of sodium hydroxide solution, and stirring;

(4) heating to 60 ℃, stirring at the rotating speed of 300rpm for 2 hours to completely react, naturally cooling to room temperature after the reaction is finished, centrifuging to separate solids, and washing out impurities in the solids by using 20.40mol of sodium formate solution;

(5) the resulting solid was first dried at 80 ℃ for 9 hours at atmospheric pressure and then dried at 120 ℃ for 9 hours under vacuum to give 16g of DUT-67 as material 1.

Example 2

The metal salt in this example is zirconium tetrachloride.

(2) 20.40mmol of organic ligand was added to the above solution and stirred at 300rpm for 10min to mix well.

(3) Then adding 24.00mmol of sodium hydroxide solution, and stirring;

(5) the resulting solid was first dried at 80 ℃ for 9 hours under atmospheric pressure and then dried at 120 ℃ for 9 hours under vacuum to give 10.5g of DUT-67.

Example 3

The metal salt in this example is zirconium tetrachloride.

(2) 27.20mmol of organic ligand was added to the above solution and stirred at 300rpm for 10min to mix well.

(3) Then adding 24.00mmol of sodium hydroxide solution, and stirring;

(5) the resulting solid was first dried at 80 ℃ for 9 hours under atmospheric pressure and then dried at 120 ℃ for 9 hours under vacuum to yield 13.3g of DUT-67.

Example 4

The metal salt in this example is zirconium tetrachloride.

(1) Dissolving 0.84mol of zirconium tetrachloride into 84.00mol of deionized water, and stirring for 30min at the rotating speed of 1000rpm to completely dissolve the zirconium tetrachloride to obtain a uniform solution;

(2) adding 0.21mol of organic ligand into the solution obtained in the step (1), and stirring at the rotating speed of 1000rpm for 30min to uniformly mix the organic ligand and the solution;

(3) adding 0.76mol of sodium bicarbonate solution;

(4) heating to 85 ℃, stirring at 1000rpm for 6 hours to completely react;

(5) after the reaction is finished, naturally cooling to room temperature, filtering to separate the solid, and washing out impurities in the solid by using 42.00mol of ethanol;

(6) the solid obtained is dried under normal pressure at 60 ℃ for 12 hours, and then dried under vacuum at 100 ℃ for 12 hours. Drying gave 90g of DUT-67 as material 3.

Example 5

The metal salt in this example is zirconium oxychloride.

(1) Dissolving 0.16mol of zirconium oxychloride into 11.00mol of N, N-dimethylacetamide, and stirring at the rotating speed of 600rpm for 20min to completely dissolve the zirconium oxychloride to obtain a uniform solution;

(2) adding 53.33mmol of organic ligand into the solution obtained in the step (1), and stirring at the rotating speed of 600rpm for 20min to uniformly mix;

(3) adding 0.20mol of sodium carbonate solution;

(4) heating to 100 ℃, stirring at the rotating speed of 600rpm for 4 hours to completely react;

(5) after the reaction is finished, naturally cooling to room temperature, centrifuging to separate the solid, and washing out impurities in the solid by 16.50mol of N, N-dimethylacetamide;

(6) the solid obtained is dried under normal pressure for 6 hours at 100 ℃, and then dried under vacuum for 6 hours at 150 ℃. After drying, 25g of DUT-67 was obtained, as material 2.

The regulator in the prior art is glacial acetic acid, which is not beneficial to the dissolution of the organic ligand, so that the organic ligand needs to be completely dissolved by using ultrasound to assist the dissolution of the organic ligand, then the mixture is sealed in a reaction kettle at 120 ℃ for reaction for 48 hours, and 230.0mg of zirconium tetrachloride reacts with 110.0mg of the organic ligand to obtain 225.1mg of DUT-67 which is marked as material 4. It can be seen that the yield is very low, the reaction time is very long and the efficiency is low. It can be seen that the preparation method in the present application can significantly improve the yield and can significantly shorten the preparation time.

And (3) analyzing a crystal structure:

the crystal structures of material 1, material 2, material 3 and material 4 obtained in the examples of the present invention were characterized by an Empyrean X-ray diffractometer. The operating conditions were: 40kV, 40mA, step size 0.01313 DEG, and the measured X-ray diffraction patterns are shown in FIG. 2, FIG. 6, FIG. 10 and FIG. 14. As can be seen from the figure, the characteristic peak of the prepared DUT-67 completely coincides with the position of the theoretical characteristic peak, which shows that the DUT-67 with uniform phase and perfect crystal structure is obtained by the equal embodiment.

And (3) analyzing the pore structure:

the DUT-67 in the above example was subjected to pore structure analysis using an Autoosorb-iQ fully automated gas adsorption analyzer. The nitrogen desorption isotherms of the DUT-67 measured at 77K are shown in fig. 3, 7, 11 and 15, and the specific surface area and pore volume calculated from the adsorption curves are shown in table 1 below, and it can be seen that the scheme in this example has a larger specific surface area and is more favorable for adsorption than the prior art.

DUT-67	Specific surface area (m)²/g)	Pore volume (cm)³/g)
			Material 1	1104	0.492
Material 2	1080	0.481
			Material 3	1152	0.513
Material 4	955	0.425

TABLE 1

The pore size distribution is shown in FIG. 4, FIG. 8, FIG. 12 and FIG. 16, and the pore size of the DUT-67 prepared in the example is centered around 0.89nm, which is a microporous material.

Scanning electron microscope analysis:

the shapes of the material 1, the material 2 and the material 3 obtained in the example are characterized by a Nova NanoSEM450 type scanning electron microscope, and as shown in FIGS. 5, 9 and 13, the obtained DUT-67 has a polyhedral structure consistent with the guidance in the literature.

The refrigeration performance of the DUT-67 obtained in the embodiment 4 in an adsorption refrigeration system is evaluated, the evaluation parameters are the refrigeration performance coefficient and the unit refrigeration capacity, the automatic sorb-iQ full-automatic gas adsorption analyzer is used for measuring the water vapor adsorption curve of the DUT-67 obtained in the embodiment 4, the test temperature is 298K, and the test relative pressure is 0.001-0.9, as shown in FIG. 17. The water vapor adsorption curve of the DUT-67 is used for calculating the refrigeration performance coefficient and the unit refrigeration capacity. When the adsorption temperature is 303K, the condensation temperature is 303K, the evaporation temperature is 283K, and the desorption temperature is 335K, the calculated refrigeration performance coefficient and the unit refrigerating capacity are respectively 0.78 kJ/kg and 152 kJ/kg. Other temperatures are unchanged, the evaporation temperature is increased, and the refrigeration performance coefficient and the unit refrigeration capacity are obviously increased. When the evaporation temperature is increased to 295K, the refrigeration performance coefficient and the unit refrigerating capacity are respectively 0.97 and 649kJ/kg, which are much higher than those of the traditional adsorbent. Taking silica gel as an example, when the adsorption temperature is 303K, the condensation temperature is 303K, the evaporation temperature is 295K and the desorption temperature is 335K, the refrigeration performance coefficient and the unit refrigeration capacity are respectively 0.60 kJ/kg and 130 kJ/kg.

In conclusion, the reaction can be carried out at lower temperature and pressure by adopting a proper raw material ratio and adding the alkaline regulator, the reaction can be promoted, and then a large amount of DUT-67 can be rapidly prepared, so that the industrial production and application are facilitated.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method of batch manufacturing DUTs-67, the method comprising:

s1: dissolving metal salt and an organic ligand in a solvent to obtain a mixed solution, wherein the molar ratio of the organic ligand to the metal salt to the solvent is 1: 2: 100-1: 4: 400;

s2: adding a regulator into the mixed solution, wherein the regulator is an alkaline regulator;

s3: and heating the solution obtained in the step S2 to enable the metal salt and the organic ligand to perform a coordination reaction to obtain the DUT-67, wherein the heating temperature is 60-100 ℃.

2. The method of claim 1, wherein the alkaline regulator is one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide and ammonia water.

3. The method according to claim 1 or 2, wherein the molar concentration ratio of the alkaline regulator to the solvent is 1: 55 to 1: 170.

4. The method of claim 1, wherein the metal salt is a zirconium metal salt.

5. The method of claim 1, wherein the organic ligand, metal salt, and solvent are present in a molar ratio of 1: 3: 225.

6. The method of claim 1, wherein step S3 further comprises washing the obtained DUT-67, and sequentially drying the DUT-67 at 60-80 ℃ under normal pressure and 100-150 ℃ under vacuum.

7. DUT-67 produced by the method of batch production of DUTs-67 according to any of claims 1 to 6.

8. The use of the DUT-67 of claim 7, wherein the DUT-67 is used in a sorption refrigeration system.