CN115558121B - Porous coordination polymer and preparation and separation method for isotopologues - Google Patents

Abstract

本发明中的配位聚合物具有可以翻折运动的翻折单元，配位聚合物允许水的同位素体通过并控制其扩散，且水的同位素体在本发明中的配位聚合物中的扩散速率不同，从而实现了对水的同位素体的分离，298K下本发明中的配位聚合物从H₂O/HDO/D₂O三元混合体系中动态分离H₂O的分离系数高达约210。此外，本发明中的配位聚合物在水和有机溶剂中都具有较高的稳定性，从而保证了水同位素体分离的可实施性。The invention discloses a porous coordination polymer and a method for preparing and isotopologue separation. The coordination polymer is self-assembled by metal ions and organic ligands through coordination bonds, wherein the organic ligands The body has the general formula in formula (I) or formula (II),

The coordination polymer in the present invention has a folding unit that can fold and move, and the coordination polymer allows the isotopologue of water to pass through and controls its diffusion, and the diffusion of the isotopologue of water in the coordination polymer of the present invention The rate is different, so that the separation of isotope of water is realized. The coordination polymer in the present invention can dynamically separate H ₂ O from the H ₂ O/HDO/D ₂ O ternary mixed system at 298K. The separation coefficient is as high as about 210 . In addition, the coordination polymer in the present invention has high stability in both water and organic solvents, thereby ensuring the practicability of water isotopologue separation.

Description

A kind of porous coordination polymer and its preparation and isotopologue separation method

technical field

The invention relates to the technical field of isotopologue separation, in particular to a porous coordination polymer and a method for preparing and isotopologue separation.

Background technique

这使得利用主体材料进行吸附分离也相当困难。在过去的几十年里，化学家们一直尝试利用多孔材料中吸附性能的差异实现水的同位素体分离，然而至今未见一例成功的报道。Isotopologues are substances with exactly the same chemical composition but different in isotopic composition, such as hydrogen isotope D ₂ /H ₂ , water isotopologue D ₂ O/HDO/H ₂ O/H ₂ ¹⁸ O, etc. The development of effective methods for the identification and separation of isotopologues is extremely important in both basic research and industrial applications, but remains a major challenge in the field of chemistry. In order to apply isotopes widely in industry, biomedicine, and scientific research, chemists try to distinguish isotopes by molecular chemistry, such as using host materials including cage compounds or rigid porous materials to capture one of the isotopes. However, because isotopologues have the same chemical structure and size, and their thermodynamic properties are very similar, it is very difficult to separate isotopologues from each other, and the isotopologue of water is the most difficult to distinguish. Water (H ₂ O) and heavy water (D ₂ O) are two typical isotopes of water, their physical and chemical properties, such as melting point (273.15K vs. 276.94K), boiling point (373.15K vs. 374.56K), bond Energy (458.9kJ mol-1 bond-1 vs 466.4kJ mol-1 bond-1), etc. are very similar, resulting in the extremely low efficiency of high-temperature multi-stage rectification technology and electrolysis water technology used in industry to separate water isotope bodies (separation Factor 1.02 ~ 2.0). Furthermore, when H ₂ O and D ² O are mixed, through proton exchange chemical equilibrium, semi-heavy water (HDO) will be rapidly generated. At 298K, the equilibrium constant K=[HDO(liquid)] ² /{[H ₂ O(liquid)]·[D ₂ O(liquid)]}=3.85, and the three always coexist. Therefore, the thermodynamic methods of proton exchange equilibrium such as the Geib-Spevack method used in industry have extremely low efficiency in separating isotopologues of water (separation factor 1.2-2.0). Furthermore, the molecular dynamic diameters of _H2O and _D2O are very small and identical

This makes adsorption separation using host materials quite difficult. In the past few decades, chemists have been trying to realize the isotopologue separation of water by utilizing the difference in adsorption properties in porous materials, but no successful case has been reported so far.

时，可产生量子隧穿效应，从而可以放大这种差异，而水的同位素体即使在低温下扩散速率也没有表现出明显的差异，从而实现有效分离。迄今为止，控制水的同位素体扩散的材料还未曾报道。On the other hand, hydrogen isotopes can be effectively separated by the kinetic quantum sieving effect at low temperatures less than 40K, because hydrogen isotopes have slightly different diffusion rates at low temperatures, and by strictly controlling the micropore diameter of porous materials equal to _D2 de Broglie wavelength

When , the quantum tunneling effect can be produced, which can amplify this difference, and the isotope of water does not show a significant difference in diffusion rate even at low temperature, so as to achieve effective separation. So far, materials that control isotopologue diffusion of water have not been reported.

Contents of the invention

The present invention aims to solve at least one of the technical problems in the above-mentioned prior art. To this end, the present invention proposes a porous coordination polymer and its preparation method and application. The coordination polymer in the present invention has a folding unit that can be folded and moved. The unique pore structure and channels inside the coordination polymer allow The isotopologue of water passes through and controls its diffusion, and the diffusion rate of the isotopologue of water in the coordination polymer in the present invention is different, thereby realizing the separation of the isotopologue of water, and under 298K, the coordination polymer in the present invention The separation coefficient of the dynamic separation of H ₂ O by the coordination polymer from the H ₂ O/HDO/D ₂ O ternary mixed system is as high as about 210; in addition, the coordination polymer in the present invention has a high performance in both water and organic solvents stability, thus ensuring the practicability of water isotopologue separation.

The first aspect of the present invention provides a coordination polymer, which is self-assembled by metal ions and organic ligands through coordination bonds.

According to the content of the first aspect of the present invention, in some embodiments of the present invention, the organic ligand has the general formula in formula (I) or formula (II):

In some preferred embodiments of the present invention, the R ₁ to R ₆ are each independently selected from one of -H, -O, -CH ₃ , -C ₂ H ₅ , -OCH ₃ .

In some preferred embodiments of the present invention, the R ₇ to R ₁₄ are each independently selected from one of -H, -O, -CH ₃ , -C ₂ H ₅ , -OCH ₃ .

In some preferred embodiments of the present invention, the 5-position of the organic ligand isophthalic acid is composed of iminostilbene, iminodibenzyl, 5H-dibenzo[b,f]azepine- Substitution by at least one of 10(11H)-keto and 10-methoxyiminostilbene.

In some preferred embodiments of the present invention, the organic ligand contains units capable of flipping movement.

In some more preferred embodiments of the present invention, the organic ligand has a structure in formula (III) or formula (IV):

In some preferred embodiments of the present invention, the metal ion is selected from one of cobalt, zinc, nickel, copper, sodium, potassium and calcium.

In some more preferred embodiments of the invention, the metal ion is from a soluble metal salt.

In some more preferred embodiments of the present invention, the metal salt is selected from cobalt nitrate, zinc nitrate, nickel nitrate, copper nitrate, sodium nitrate, potassium nitrate, calcium nitrate, copper acetate, potassium acetate, cobalt acetate, zinc acetate, One of copper sulfate, zinc sulfate, sodium sulfate, cobalt sulfate, zinc sulfate, copper chloride, zinc chloride, cobalt chloride, nickel chloride, and calcium chloride.

In some preferred embodiments of the present invention, the coordination number of the coordination polymer is 2.

In some preferred embodiments of the present invention, the coordination polymer is a porous coordination polymer.

且所述孔径具有动态调节能力。In some more preferred embodiments of the present invention, the pore size of the coordination polymer is

And the aperture has the ability of dynamic adjustment.

反应得到的有机配体与含有金属离子的盐通过配位键自组装而成，其中X为卤素原子。The second aspect of the present invention provides a method for preparing the coordination polymer described in the first aspect of the present invention, the coordination polymer is obtained by

The organic ligand obtained by the reaction and the salt containing metal ions are self-assembled through coordination bonds, wherein X is a halogen atom.

According to the second aspect of the present invention, in some embodiments of the present invention, the metal ion is from a soluble metal salt.

In some preferred embodiments of the present invention, the metal salt is selected from cobalt nitrate, zinc nitrate, nickel nitrate, copper nitrate, sodium nitrate, potassium nitrate, calcium nitrate, copper acetate, potassium acetate, cobalt acetate, zinc acetate, sulfuric acid One of copper, zinc sulfate, sodium sulfate, cobalt sulfate, zinc sulfate, copper chloride, zinc chloride, cobalt chloride, nickel chloride, and calcium chloride.

In some more preferred embodiments of the present invention, the organic ligand is prepared by the following steps:

2-二环己基磷-2′,4′,6′-三异丙基联苯、碳酸铯和三(二亚苄基丙酮)二钯(0)置于容器中，在惰性气体的保护下加入溶剂进行反应；S1. Will

2-Dicyclohexylphosphine-2′,4′,6′-triisopropylbiphenyl, cesium carbonate and tris(dibenzylideneacetone)dipalladium(0) are placed in a container under the protection of an inert gas Add solvent to react;

完全消失时停止反应，加入乙酸乙酯和硅藻土，滤掉固体后得到的有机相进行萃取；S2. When

Stop the reaction when it disappears completely, add ethyl acetate and diatomaceous earth, and extract the organic phase obtained after filtering off the solid;

S3. After collecting the organic phase, perform column chromatography separation and elution to obtain compound 1

S4. After compound 1 is dissolved in an organic solvent, NaOH aqueous solution is added for reflux reaction;

S5. Remove the organic solvent after cooling, adjust the pH value, filter out the solid, wash and dry to obtain the organic ligand.

In some preferred embodiments of the present invention, the solvent described in step S1 is ultra-dry toluene.

In some preferred embodiments of the present invention, the reaction temperature in step S1 is 110-120°C.

In some preferred embodiments of the present invention, the reaction time in step S1 is 14-18 hours.

In some preferred embodiments of the present invention, the reaction is monitored by thin-layer chromatography in step S2.

In some preferred embodiments of the present invention, the sequence of extraction in step S2 is three extractions with ethyl acetate and three extractions with saturated brine.

In some preferred embodiments of the present invention, in step S3, the organic phase is dried before column chromatography separation.

In some preferred embodiments of the present invention, the drying treatment method may be drying using anhydrous magnesium sulfate.

In some preferred embodiments of the present invention, the eluent eluted in step S3 is ethyl acetate/n-hexane.

In some more preferred embodiments of the present invention, the volume ratio of ethyl acetate to n-hexane is (3-6):1.

In some preferred embodiments of the present invention, the yield of compound 1 in step S3 is 55-60%.

In some preferred embodiments of the present invention, the organic solvent in step S4 is a mixture of tetrahydrofuran (THF) and methanol (MeOH).

In some more preferred embodiments of the invention, the volume ratio of THF and MeOH is 1:1.

In some preferred embodiments of the present invention, the concentration of the NaOH aqueous solution in step S4 is 1-3M.

In some preferred embodiments of the present invention, the time of the reflux reaction in step S4 is 14-18 hours.

In some preferred embodiments of the present invention, the method for removing the organic solvent in step S5 includes a spin drying method.

In some preferred embodiments of the present invention, the pH value in step S5 is 1-2.

In some more preferred embodiments of the invention, glacial hydrochloric acid is used for pH adjustment.

In some preferred embodiments of the present invention, the solid is washed with water for 2-4 times in step S5.

In some preferred embodiments of the present invention, the drying temperature in step S5 is 50-70°C.

In some preferred embodiments of the present invention, the drying time in step S5 is 10-14 hours.

The content of the third aspect of the present invention provides the application of the coordination polymer described in the first aspect of the present invention in the separation of isotopologues of water.

According to the content of the third aspect of the present invention, in some embodiments of the present invention, the coordination polymer needs to be activated before use.

In some preferred embodiments of the present invention, the activation method is standing in vacuum at a temperature of 353K-393K for 8-15 hours.

Wherein, the appropriate high temperature is to fully volatilize the solvent in the pores of the coordination polymer of the present invention, thereby increasing the adsorption capacity of the coordination polymer to water and realizing more effective separation of water isotopologues.

In some preferred embodiments of the present invention, the coordination polymer is separated at a temperature of 278K-473K.

In some preferred embodiments of the present invention, the adsorption capacity of the coordination polymer in water is 50-70 mL/g.

In some preferred embodiments of the present invention, the isotopologues of water include D ₂ O, HDO, H ₂ O, H ₂ ¹⁸ O.

In some preferred embodiments of the present invention, the coordination polymer is used to separate two or more isotopologues of water.

The inventor proposes a "diffusion control" strategy with low energy consumption to achieve effective separation of isotopologues of water. The essence of this strategy is to control the diffusion of water isotopologues and amplify the difference in the diffusion rate of water isotopologues by using a dynamic "locally flexible" framework material. The dynamic "local flexible" framework material will preferentially adsorb one isotopologue molecule from the water isotopologue mixture according to the kinetic difference, so as to realize the effective recognition of the water isotopologue in dynamics. The specific method is to establish a "locally flexible" porous coordination polymer system in which the molecular diffusion process of the isotopologue of water is controlled by the folding movement of the ligand group. A temperature-responsive dynamic "switch" programmed into the cage-like pore walls of porous coordination polymers (PCPs) with a rigid framework exhibits a temperature-responsive adsorption behavior, which can amplify the subtle differences in the diffusion rate between isotopologues of water to achieve Highly selective adsorption of _H2O . At 298K _, the coordination polymer in the present invention can dynamically separate H 2 O from the H ₂ O/HDO/D ₂ O ternary mixed system, and the separation coefficient is as high as about 210.

The beneficial effects of the present invention are:

(1) The coordination polymer in the present invention has a folding unit that can fold and move, and the coordination polymer allows the isotopologue of water to pass through and controls its diffusion, and the isotopologue of water in the coordination polymer of the present invention Diffusion rate in different, so as to realize the separation of isotope of water, coordination polymer in the present invention under 298K from H ₂ O/HDO/D ₂ O ternary mixed system dynamic separation coefficient of H ₂ O separation Up to about 210.

(2) The coordination polymer in the present invention has higher stability in water and various organic solvents, no matter after soaking at normal temperature or high temperature, the powder X-ray diffraction analysis of the coordination polymer in the present invention (PXRD) spectrograms did not change significantly, thereby ensuring the practicability of water isotopologue separation.

Description of drawings

Fig. 1 is the hydrogen spectrogram of the organic ligand IDB-ipa in the embodiment of the present invention 2;

Fig. 2 is the carbon spectrogram of organic ligand IDB-ipa in the embodiment of the present invention 2;

Fig. 3 is the mass spectrogram of organic ligand IDB-ipa in the embodiment of the present invention 2;

Fig. 4 is the folding motion potential energy curve of the DBAP ring in the organic ligand of Example 1 of the present invention and the IDB ring in the organic ligand of Example 2 of the present invention;

Fig. 5 is the optical microscope photograph of the coordination polymer prepared in the embodiment of the present invention;

Figure 6 is the activated crystal structure of FDC-1a and FDC-2a;

Fig. 7 is the PXRD spectrum of the coordination polymer prepared in the embodiment of the present invention soaked in different solvents for 7 days;

Fig. 8 is the adsorption-desorption curve and time-dependent adsorption curve of the coordination polymer in the embodiment of the present invention for _H2O and _D2O at 298K;

Fig. 9 is a panoramic view of the pressure-diffusion rate-adsorption amount of the coordination polymer adsorbing H ₂ O and D ₂ O in the examples of the present invention at different temperatures;

Fig. 10 is the McCabe-Thiele diagram of the separation of water isotopologues by the coordination polymer in the embodiment of the present invention at a temperature of 298K;

Fig. 11 shows the variation of the H ₂ O separation factor in the adsorption phase of FDC-1a and FDC-2a in the examples of the present invention with the H ₂ O content in the raw material steam at a temperature of 298K.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments, and the advantages and characteristics of the present invention will become clearer along with the description. However, these embodiments are only exemplary and do not constitute any limitation to the scope of the present invention. Those skilled in the art should understand that the details and forms of the technical solutions of the present invention can be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the protection scope of the present invention.

The synthesis of embodiment 1 organic ligand

The synthetic route of the organic ligand in embodiment 1 is:

Concrete preparation steps are:

其质量为11.18g，产率为58％。将含有化合物/>

(5.0g,12.95mmol)的THF/MeOH(100mL,1/1v/v)溶液加入500mL圆底烧瓶中，然后加入2M的NaOH水溶液(100mL,200mmol)，回流反应16h。冷却至室温后，旋转蒸发除掉有机溶剂，再用3％的冰盐酸调节溶液pH至1-2，滤出固体，用去离子水洗涤三次。60℃真空干燥12h，得到白色粉末/>

记为DBAP-ipa，其质量为9.1g，产率为98％。Dimethyl 5-iodoisophthalate (19.20g, 60.0mmol, 1.2eq), iminostilbene (9.66g, 50.0mmol, 1.0eq), 2-dicyclohexylphosphine-2′,4′,6 '-triisopropylbiphenyl (XPhos, 1.19g, 2.5mmol, 0.05eq), cesium carbonate ( _Cs2CO3 , _32.58g , 100.0mmol, 2.5eq) and tris(dibenzylideneacetone)dipalladium ( 0) (Pb ₂ (dba) ₃ , 1.37g, 1.5mmol, 0.03 equivalents) was placed in a 500mL round bottom flask, the air in the flask was evacuated and filled with argon, and under the protection of argon, 200mL of ultra-dry toluene was added (toluene), stirred at 115°C for 16h. Adopt thin-layer chromatography (TLC) to monitor the reaction, stop the reaction when the raw material iminostilbene completely disappears and cool to room temperature, add 50mL ethyl acetate and diatomaceous earth in the flask, filter off the solid after stirring, the organic phase is washed with ethyl acetate Esters (200mL×3 times) and saturated brine (100mL×3 times) were extracted. Collect the organic phase, dry it with anhydrous magnesium sulfate, spin dry and load the sample for column chromatography separation, elute with ethyl acetate/n-hexane (volume ratio (3-6): 1), and vacuum-dry at 80°C for 12h to obtain a powder

It has a mass of 11.18 g and a yield of 58%. will contain compound />

(5.0g, 12.95mmol) in THF/MeOH (100mL, 1/1v/v) was added to a 500mL round bottom flask, then 2M NaOH aqueous solution (100mL, 200mmol) was added, and the reaction was refluxed for 16h. After cooling to room temperature, the organic solvent was removed by rotary evaporation, and the pH of the solution was adjusted to 1-2 with 3% glacial hydrochloric acid, and the solid was filtered out and washed three times with deionized water. Vacuum drying at 60°C for 12 hours to obtain a white powder/>

Recorded as DBAP-ipa, its mass is 9.1g, and the yield is 98%.

The synthesis of embodiment 2 organic ligands

替换为/>

The synthetic route of the organic ligand in embodiment 2 is similar to embodiment 1, difference is that compound

replace with />

Concrete synthetic route is:

The obtained organic ligand is recorded as IDB-ipa, its mass is 9.1 g, and the yield is 98%.

Figures 1 to 3 are the hydrogen spectrum, carbon spectrum and mass spectrum of the organic ligand IDB-ipa, which is capable of turning over and moving. It can be seen from the figures that the organic ligand IDB- ipa, also calculated the relationship between the folding energy barrier and the dihedral angle (C ₁ N ₁ C ₂ C ₃ ) in the organic ligand DBAP-ipa and IDB-ipa in Examples 1 and 2 of the present invention, wherein the dihedral Angle (C ₁ N ₁ C ₂ C ₃ ) ranges from 100°-160° (10° interval), as shown in Figure 4, wherein, Figure 4a is the folding energy of the DBAP ring in the organic ligand DBAP-ipa The relationship between the barrier and the dihedral angle C ¹ N ¹ C ² C ³ , Figure 4b shows the relationship between the folding energy barrier and the dihedral angle C ¹ N ¹ C ² C ³ of the IDB ring in the organic ligand IDB-ipa. It can be seen from Fig. 4 that no matter it is the DBAP ring or the IDB ring, the energy change (ΔE) of the turning motion is very small, and the change ΔE relative to the dihedral angle of 20° is less than 20kJ mol ^-1 . The above results show that the energy change of the DBAP ring or IDB ring in the organic ligand in the embodiment of the present invention is small when it is turned over, and it can effectively occur at a very low temperature, and the turning motion will increase with the increase of temperature. amplitude increased.

Synthesis of embodiment 3 coordination polymer

Dissolve 500 mg (1.40 mmol) of DBAP-ipa in Example 1 in 50 mL of dimethylacetamide (DMA) at 30°C, then add 676 mg (2.80 mmol) of Cu(NO ₃ ) ₂ ·3H ₂ O aqueous solution (50 mL). The mixed solution was heated in an oven at 80°C for 24 hours to obtain a dark green block single crystal with a size close to 1mm, as shown in Figure 5a, the crystal was filtered, washed with DMA and water three times, and dried at 30°C to obtain Cu(DBAP) (Denoted as FDC-1, 538 mg, yield 78%).

The synthesis of embodiment 4 coordination polymer

500mg (1.40mmol) of IDB-ipa in Example 2 was dissolved in 50mL of DMA at 30°C, and then 676mg (2.80mmol) of Cu(NO ₃ ) ₂ ·3H ₂ O aqueous solution (50mL) was added. The mixed solution was heated in an oven at 80°C for 24 hours to obtain a dark green block single crystal with a size close to 1mm, as shown in Figure 5b, the crystal was filtered, washed with DMA and water three times, and dried at 30°C to obtain Cu(IDB) (Denoted as FDC-2, 538 mg, yield 80%).

Of course, those skilled in the art can synthesize other organic ligands according to the above steps, and self-assemble with different metal ions through coordination bonds to prepare other coordination polymers.

Application of FDC-1 and FDC-2 in Water Isotopologue Separation

1. Experimental process

1. Sample loading and activation: the coordination polymer (0.40g) in embodiment 3 or 4 is packed in the cylindrical sample cell (diameter is 8mm), vacuum-dried and activated at 393K temperature for 10h, then the sample cell is installed On the BEL-CAT II instrument, activate in situ on the instrument for 1h, and purge helium at a constant rate of 10sccm for 1h during the activation process; the activation process needs to ensure that the solvent adsorbed by the sample is completely removed, and the activated samples are respectively recorded as FDC -1a and FDC-2a.

2. Adsorption process: Cool down from 393K to 298K at a rate of 10K min ^-1 . When the temperature reaches the specified temperature, the mixed steam blows through the sample at a rate of 10 sccm (the flow rate of the mixed steam is controlled by a mass flow meter). During the adsorption process, the temperature Always stay at 298K.

3. Exhaust the unadsorbed vapor in the sample cell: at a temperature of 298K, continuously purge helium at a flow rate of 10 sccm for 1 hour, and discharge the excess vapor in the sample cell and pipeline.

4. Desorption and separation detection of adsorbed gas: Raise the temperature of the sample cell to 393K at a speed of 10K min ^-1 , at this time, the vapor adsorbed inside the sample is desorbed, and at the same time, the helium gas is continuously purged at a speed of 10 sccm to desorb the gas. The attached vapor is sent to the detector, and the desorbed water vapor is detected by mass spectrometry. The ratio of released _H2O , HDO and _D2O was calculated by integrating the area of the current signal after subtracting the baseline.

Those skilled in the art can also choose different activation temperatures according to actual needs, not limited to 393K.

Those skilled in the art can also select the adsorption temperature according to actual needs, for example, the adsorption temperature can also be 278K, 288K, 308K, 323K or 393K.

Among them, the _H2O separation factor is defined as:

In the formula, X _H2O represents the concentration of H ₂ O in the adsorption phase; Y _H2O represents the concentration of H ₂ O in the feed gas; X _HDO represents the concentration of HDO in the adsorption phase; Y _HDO represents the concentration of HDO in the feed gas; X _D2O represents The concentration of D ₂ O in the adsorption phase; Y _D2O represents the concentration of D ₂ O in the feed gas.

2. Experimental results

1. Crystal structures of activated FDC-1a and FDC-2a

的三角形“门”，这个“门”由两个间苯二甲酸和DBAP中两个苯环围绕而成。同样，FDC-2a中的“门”是由两个间苯二甲酸和IDB中两个苯环围绕而成，尺寸为/>

略小于FDC-1a。由此可见，配体结构上的微调带来扩散通道的尺寸变化，这一变化虽然微小，但是对于分离具有非常小的分子动力学直径/>

的水同位素体分子来说至关重要。The crystal structures of FDC-1a and FDC-2a in the activated state are shown in Figure 6, where Figure 6a is the activated crystal structure of FDC-1a and FDC-2a, and Figure 6b is the pore structure in FDC-1a and FDC-2a , Figure 6c is the diffusion channel and structure of FDC-1a, Figure 6d is the diffusion channel and structure of FDC-2a, as can be seen from Figure 6, FDC-1a and FDC-2a are composed of many nanopore cages of the same size and Composed of extremely narrow diffusion channels, there are 6 identical diffusion channels from one cell cage to the adjacent cell cage. One of all diffusion channels in FDC-1a

The triangular "gate" is formed by two isophthalic acid and two benzene rings in DBAP. Similarly, the "gate" in FDC-2a is surrounded by two isophthalic acid and two benzene rings in IDB, with a size of />

Slightly smaller than FDC-1a. It can be seen that the fine-tuning of the ligand structure brings about a change in the size of the diffusion channel, which is small, but has a very small molecular dynamics diameter for separation />

It is very important for the water isotopologue molecules.

2. Crystal stability of activated FDC-1a and FDC-2a

FDC-1a and FDC-2a were immersed in water (298K or 363K), methanol (298K or 333K) and N,N-dimethylformamide (DMF) (298K or 393K) for 7 days, respectively. Figure 7 is the PXRD spectrum of FDC-1a and FDC-2a soaked in different solvents for 7 days, wherein, Figure 7a is the PXRD spectrum of FDC-1a soaked in different solvents for 7 days, Figure 7b is FDC-2a in different solvents The PXRD spectrogram after soaking in the solvent for 7 days, as can be seen from Figure 7, the PXRD curves of FDC-1a and FDC-2a after soaking in water, methanol and DMF are basically unchanged, indicating that FDC-1a and FDC-2a show Excellent hydrothermal and solvent stability.

3. Research on the adsorption behavior of FDC-1a and FDC-2a and the kinetics of the adsorption process:

First, the adsorption-desorption curves of FDC-1a and FDC-2a for H ₂ O and D ₂ O were studied under different relative pressures (P/Ps) at 298K. The results are shown in Figure 8a and Figure 8b, where the abscissa represents the pressure, and the ordinate represents the amount of adsorption. It can be seen from Figure 8a and Figure 8b that at a temperature of 298K, when the P/Ps is 0.98, FDC-1a and FDC-2a adsorb H ₂ O/D ₂ O The ratios are 1.39 and 1.64, respectively, indicating that FDC-1a and FDC-2a will preferentially adsorb H ₂ O in the water isotope. The adsorption and desorption curves of FDC-1a and FDC-2a for H ₂ O and D ₂ O under different exposure times were further studied, as shown in Figure 8c and 8d, it can be seen from the figure that with the prolongation of exposure time, The adsorption capacity of FDC-1a to H ₂ O and D ₂ O was significantly increased to about 60mL g ^-1 , and the adsorption capacity of FDC-2a to H ₂ O and D ₂ O was increased to about 55 mL g ^-1 , indicating that FDC-1a and FDC- The diffusion kinetics of 2a are determined by the diffusion time. Figure 9 is a panorama of the pressure-diffusion rate-adsorption amount of the coordination polymer adsorbing H ₂ O and D ₂ O in the examples of the present invention at different temperatures, where the x-axis is the pressure, the y-axis is the diffusion rate, and the z-axis is Adsorption amount, along the direction of the arrow, the temperature increases from 278K to 323K in turn, where Figure 9a is the pressure-diffusion rate-adsorption volume panorama of FDC-1a adsorbing H ₂ O, and Figure 9b is FDC-1a adsorption D ₂ O The pressure-diffusion rate-adsorption volume panorama of FDC-2a, Figure 9c is the pressure-diffusion rate-adsorption volume panorama of FDC-2a adsorbed H ₂ O, Figure 9d is the pressure-diffusion rate-adsorption volume of FDC-2a adsorption D ₂ O It can be seen from Figure 9 that when the temperature increases from 278K to 323K, the adsorption capacity of FDC-1a for H ₂ O increases significantly from 1.7mL g ^-1 to 32.6mL g ^-1 , and FDC-2a for H 2 O The adsorption capacity of ₂ O increased from 1.3 mL g ^-1 to 15.1 mL g ^-1 , the adsorption capacity of FDC-1a on D ₂ O increased from 0.6 mL g ^-1 to 24.4 mL g ^-1 , the adsorption of FDC-2a on D2O The amount increased from 0.5 mL g ^-1 to 11.8 mL g ^-1 . As the temperature increased, the adsorption amounts of H ₂ O and D ₂ O in FDC-1a and FDC-2a increased significantly, indicating that their adsorption behavior was controlled by temperature. Unlike conventional porous materials, where the gas/vapor adsorption capacity decreases with increasing temperature, the opposite adsorption behavior of this system is typical of diffusion-controlled systems.

4. Diffusion rate of H ₂ O and D ₂ O at different temperatures

Further studied the diffusion rate of _H2O and _D2O in the coordination polymer in the embodiment of the invention (the determination method of the isotopologue diffusion rate of water is to measure its adsorption curve at a certain temperature, record The raw data of the pressure over time at each measurement point are then solved by the Crank equation to finally obtain the diffusion rate (Ds) of the water isotope at different temperatures). The results of the diffusion rates of H ₂ O and D ₂ O at different temperatures are shown in Fig. 9. It can be seen from Fig. 9 that the diffusion rates of FDC-1a and FDC-2a for H ₂ O or D ₂ O are all the same at low temperatures. Small, the diffusion rates of FDC-1a and FDC-2a towards H ₂ O or D ₂ O gradually increased with increasing temperature and pressure. At 298K, the diffusion rates Ds of H ₂ O in FDC-1a and FDC-2a are 1.56×10 ^-2 and 1.11×10 ^-2 R ² s ^-1 , and D ₂ O in FDC-1a and FDC-2a The values of diffusion rate Ds are 2.05×10 ^-3 and 1.37×10 ^-3 R ² s ^-1 respectively. It is obvious that in FDC-1a and FDC-2a, the diffusion rate of H ₂ O is far greater than that of D ₂ O, They are 7.6 and 8.1 times that of D ₂ O, respectively. On the other hand, at 298K, the diffusion rates of H ₂ O and D ₂ O in FDC-1a were 1.4 and 1.5 times that of FDC-2a, indicating that the diffusion kinetics of FDC-1a was faster and FDC-2a was faster than that of FDC-2a. 1a has smaller diffusion channels and lower diffusion rates.

5. Results of water isotopologue separation

The dynamic separation performance of FDC-1a and FDC-2a to the mixed vapor of water isotopologue was studied by temperature programmed adsorption-desorption (TPD)-mass spectrometry at 298K. Fig. 10 is the McCabe-Thiele diagram of the separation of water isotopologues by the coordination polymer in the embodiment of the present invention at a temperature of 298K, wherein the abscissa is the steam content ratio of the water isotopologue raw material, and the ordinate is water in the adsorption phase Isotopologue adsorption ratio, Fig. 10a is the McCabe-Thiele plot of FDC-1a for the separation of water isotopologues, and Fig. 10b is the McCabe-Thiele plot of FDC-2a for the separation of water isotopologues, from Fig. 10a and Fig. 10b, it can be clearly seen that in the ternary blend steam of H ₂ O/HDO/D ₂ O, FDC-1a and FDC-2a selectively change from H ₂ O/HDO/D Adsorption of H ₂ O in the ₂ O mixture resulted in obvious enrichment of H ₂ O. Even in the mixed steam of H ₂ O:HDO:D ₂ O=0.3:9.3:90.4, the H ₂ O adsorption ratios of FDC-1a and FDC-2a still reached 26.8% and 38.6%, respectively, and the corresponding H ₂ O The separation factors are 124 and 212 respectively, as shown in Figure 11. Figure 11 shows the change of the H ₂ O separation factor in the adsorption phase of the coordination polymer in the embodiment of the present invention with the H ₂ O content in the raw material steam at a temperature of 298K. Wherein, the abscissa is the proportion of H ₂ O in the water isotopologue raw material, and the ordinate is the separation factor of H ₂ O. It can be seen from the figure that the adsorption ratio of FDC-2a to H ₂ O and the separation factor of H ₂ O are higher than that of FDC-1a, which is attributed to the stricter diffusion control of water isotopologues in FDC-2a, which further amplifies the Small differences in diffusion rates of water isotopologues.

Through the above research, it can be shown that the reason why the coordination polymer in the embodiment of the present invention can separate the isotope of water in the range of 278 ~ 473K is that the coordination polymer in the embodiment of the present invention can allow the isotope of water By controlling its diffusion, it is possible to amplify the subtle difference in the diffusion rate between water isotopologues and achieve highly selective adsorption and separation of H ₂ O.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (8)

1. A coordination polymer, characterized in that the coordination polymer is self-assembled by a metal ion and an organic ligand through coordination bonds, wherein the organic ligand has a general formula in formula (i) or formula (ii):

；/>

；

wherein the R is ₁ ~R ₆ Are independently selected from-H, -CH ₃ 、-C ₂ H ₅ 、-OCH ₃ One of the R ₇ ~R ₁₄ Are independently selected from-H, -CH ₃ 、-C ₂ H ₅ 、-OCH ₃ One of the following; the metal ion is copper; the pore diameter of the coordination polymer is 2.55-2.65A.

2. The coordination polymer of claim 1 wherein said organic ligand intermediate phthalic acid is substituted in the 5-position with at least one of iminostilbene, iminodibenzyl, 10-methoxyiminostilbene.

3. The coordination polymer of claim 1 wherein the organic ligand has a structure in formula (iii) or formula (iv):

；/>

。

4. the coordination polymer of claim 1 wherein the coordination polymer has a coordination number of 2.

5. A method for producing a coordination polymer according to any one of claims 1 to 4, wherein the coordination polymer is produced by

And->

Or (b)

The organic ligand obtained by the reaction and the salt containing metal ions are self-assembled through coordination bonds, wherein X is a halogen atom.

6. The use of the coordination polymer according to any one of claims 1 to 4 for isotopologue separation of water.

7. The use according to claim 6, wherein the coordination polymer is isolated at a temperature of 278K-473K.

8. The use of claim 6, wherein the isotopologue of water comprises D ₂ O、HDO、H ₂ O、H ₂ ¹⁸ O。

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