Use of a metal-organic framework material for removing trace amounts of benzene from cyclohexane

Abstract

The application belongs to the technical field of metal organic coordination polymer materials and crystalline materials, and particularly relates to application of a metal organic framework material in removal of trace benzene in cyclohexane. The metal organic framework material Zn-Ade-TCPE is synthesized by 4,4',4'',4'''-(ethylene-1,1,2,2-tetrayl) tetrakisbenzoic acid, adenine and zinc nitrate hexahydrate under a solvent thermal condition. The Zn-Ade-TCPE has a slit-shaped pore structure, and the pore structure characteristics improve selective adsorption capacity of the material for benzene molecules. In addition, nitrogen, oxygen and other atoms or groups on the pore wall of the Zn-Ade-TCPE produce multiple interactions with the adsorbed benzene molecules, and the affinity between the two is improved. The synergistic effect of these factors makes the material exhibit excellent benzene / cyclohexane separation capacity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal-organic coordination polymer materials, and particularly relates to application of a metal-organic framework material in removal of trace benzene in cyclohexane. BACKGROUND

[0002] Benzene and cyclohexane are two important chemicals in the petrochemical industry, and their separation is crucial in various industrial processes. However, due to the close boiling points of the two compounds (benzene: 80.1℃, cyclohexane: 80.7℃), similar molecular sizes, and easy formation of azeotropes, traditional distillation methods are inefficient and energy-intensive, making the separation of the two compounds a great challenge. Cyclohexane is widely used in the production of adipic acid and caprolactam, which are precursors of nylon. The production of high-purity cyclohexane is crucial for nylon production and the production of some pharmaceutical intermediates and high-purity solvents. On the other hand, benzene is a class I carcinogen, and even a very low concentration of benzene in cyclohexane can pose a threat to public health and the environment. Industrially, cyclohexane is generally produced by the catalytic hydrogenation of benzene. The removal of trace amounts of unreacted benzene from the cyclohexane product is technically challenging and requires complex processes and cumbersome process operations, with extremely high energy consumption. Therefore, it is of great significance to develop efficient and energy-saving materials and methods to address this problem.

[0003] An ideal adsorbent for removing trace benzene from cyclohexane should at least have two characteristics: high benzene / cyclohexane adsorption selectivity and high adsorption capacity for trace benzene in benzene / cyclohexane mixtures. However, most reported adsorbents with high benzene / cyclohexane adsorption selectivity have low benzene adsorption capacity at low partial pressure. Without high adsorption selectivity, even if they have high benzene adsorption capacity at low partial pressure in single-component adsorption, their performance in benzene / cyclohexane mixture separation still cannot meet the actual needs. Currently, no adsorbent has been found to meet both requirements.

[0004] Among the various crystalline materials reported for this separation, MOFs have attracted much attention due to their high surface area, tunable pore size, and multiple functions. Some MOFs, such as MFM-300(Sc), Mn-DHBQ, and MAF-stu-13, have shown significant selectivity and adsorption capacity for benzene in cyclohexane. However, the removal performance of MOF adsorbents for very low concentration benzene in cyclohexane, especially under liquid phase conditions, has rarely been studied and confirmed. SUMMARY

[0005] In view of the problems of difficult separation of benzene and cyclohexane, high energy consumption and low purity in the prior art, the application provides application of a metal organic framework material in removal of trace benzene in cyclohexane.The MOF exhibits a molecular sieve effect in separation of benzene and cyclohexane, and can be used for capture and removal of low-concentration benzene, so that efficient purification of cyclohexane is realized.

[0006] The application is realized by the following technical scheme:

[0007] Application of a metal organic framework material in removal of trace benzene in cyclohexane.

[0008] Further, the metal organic framework material is a Zn(II)-based metal organic framework material Zn-Ade-TCPE constructed by mixed ligands, and the chemical formula is C 116 H 96 N 14 O 30 Zn 7， The yellow block crystal material is prepared by a solvothermal reaction of an organic ligand H4TCPE, adenine and Zn(NO3)2.6H2O, wherein H4TCPE is 4,4',4'',4'''-(ethylene-1,1,2,2-tetrayl) tetrabenzoic acid, and the molecular formula is C 30 H 20 O8。

[0009] Further, the molar ratio of the adenine, H4TCPE and Zn(NO3)2.6H2O is 1.5:1:2.5, the volume ratio of DMA and water in the mixed solvent is 1:1, and the volume (mL) of the solvent corresponding to each millimole of the organic ligand H4TCPE is 1:60.

[0010] Further, the solvothermal reaction temperature is 120 DEG C, and the reaction time is 24 hours.

[0011] Further, the metal organic framework material can realize removal of trace benzene in cyclohexane in gas phase and liquid phase.

[0012] Further, the metal organic framework material can be recycled.

[0013] Further, from the perspective of crystal structure, the Zn-Ade-TCPE belongs to an orthorhombic system, the space group is Pcca , the cell parameters are V = 14341(8) Å 3 , a = 32.5934(11) Å, b = 13.5555(4) Å, c= 32.4592(10)Å. The Zn-Ade-TCPE has a three-dimensional framework structure, which includes chain units formed by Zn atoms coordinated with N atoms on the adenine ring, and the chain units are connected by deprotonated H4TCPE to form a three-dimensional framework structure. There are two kinds of cavities in the three-dimensional framework structure of Zn-Ade-TCPE, and the cavities are connected by very narrow pore openings, about 4.2x6.7Å, in the form of slits. The thinner benzene molecules can pass through, and the thicker cyclohexane is inhibited from entering the cavities, so as to realize the high selective separation of the two.

[0014] Further, the method for activating the Zn-Ade-TCPE material is: washing the sample with DMA solvent, then soaking in methanol solvent, performing solvent exchange for 3-4 times, then drying the sample soaked in methanol at 60°C, and degassing the sample at 120°C for 8 hours to obtain a desolvated dry sample of the material.

[0015] Further, the purity of cyclohexane separated by the Zn-Ade-TCPE reaches more than 99.9%.

[0016] The beneficial technical effects of the present application are:

[0017] The present application provides a metal organic framework (MOF) adsorbent which exhibits molecular sieve effect on benzene and cyclohexane, and the MOF has extremely high benzene adsorption capacity and extremely low cyclohexane adsorption capacity under low pressure conditions. The Zn-Ade-TCPE performs well in selectively adsorbing benzene in cyclohexane, whether in gas phase or liquid phase, even when the concentration of benzene is as low as ppm level. The MOF has record-high benzene / cyclohexane adsorption selectivity (216, 723 and 1027) in liquid mixtures of benzene and cyclohexane (v / v = 1:1, 1:10 and 1:20), and can effectively capture benzene molecules even in low partial pressure gas phase (for example, 2.49 mmol / g at 8.2Pa) or in low concentration in liquid cyclohexane (for example, 128 mg / g at 20 ppm). Through the adsorbent, a simple room temperature stripping step can remove trace benzene (1000 ppm) in liquid cyclohexane, and produce cyclohexane with a purity of more than 99.999%.

[0018] The excellent benzene / cyclohexane separation performance of Zn-Ade-TCPE is attributed to its unique pore structure and its strong interaction with benzene molecules. Zn-Ade-TCPE is prepared from two ligands, zinc ions, adenine and 4,4',4'',4'''-(ethene-1,1,2,2-tetrayl) tetrabenzoic acid (H4TCPE). The resulting three-dimensional framework structure has two types of cavities with extremely narrow windows between the cavities, in the form of slits. The high selectivity of Zn-Ade-TCPE for adsorbing benzene molecules from cyclohexane is attributed to both the unique pore structure and the rich interactions with benzene molecules. The microporous pore walls formed by adenine can form multiple interactions with benzene molecules, such as π-π stacking and N-H···π interactions, to enhance the affinity between them. Both of the above reasons contribute to the high performance of Zn-Ade-TCPE in capturing benzene molecules. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 SEM image of Zn-Ade-TCPE crystals prepared in Example 1.

[0020] Figure 2 Structure and composition of Zn-Ade-TCPE: (a) molecular structure of the ligand; (b) 1D chain unit; (c) three-dimensional framework structure of Zn-Ade-TCPE. Zn is green; O is red; N is blue; C is black.

[0021] Figure 3 Pore distribution diagram of Zn-Ade-TCPE.

[0022] Figure 4 Thermogravimetric analysis diagram of Zn-Ade-TCPE.

[0023] Figure 5 Powder diffraction patterns of Zn-Ade-TCPE samples and samples after various treatments and tests.

[0024] Figure 6 Adsorption isotherm diagram of benzene and cyclohexane of Zn-Ade-TCPE.

[0025] Figure 7 Five-cycle adsorption isotherm test diagram of benzene of Zn-Ade-TCPE.

[0026] Figure 8 Vapor breakthrough curve of benzene and cyclohexane of Zn-Ade-TCPE (nitrogen stream containing about 0.51% benzene (Bz) and about 4.75% cyclohexane (Cy) vapor as inlet gas).

[0027] Figure 9GC-FID chromatograms of benzene and cyclohexane in the inlet or outlet gas (with a nitrogen stream containing approximately 0.51% benzene (Bz) and approximately 4.75% cyclohexane (Cy) vapors as the inlet gas).

[0028] Figure 10 Vapor breakthrough curves for benzene and cyclohexane in Zn-Ade-TCPE (benzene and cyclohexane 100 and 900 ppm; 500 and 500 ppm).

[0029] Figure 11 The GC-FID chromatograms of benzene and cyclohexane in the inlet or outlet gas are shown (the inlet gas contains 100 and 900 ppm of benzene and cyclohexane, respectively).

[0030] Figure 12 The graph shows the concentration of benzene (Bz) in the outlet gas monitored by GC-FID during the breakthrough experiment (the concentrations of benzene and cyclohexane in the inlet gas were 100 and 900 ppm, respectively).

[0031] Figure 13 The mass spectrometry signal intensity maps of benzene and cyclohexane released after the breakthrough experiment were obtained by heating the MOF sample with a nitrogen gas flow at 120°C (the concentrations of benzene and cyclohexane in the inlet gas of the breakthrough experiment were 500 and 500 ppm, respectively).

[0032] Figure 14 The substances adsorbed by Zn-Ade-TCPE 1 H NMR spectrum.

[0033] Figure 15 This is a comparison of the adsorption selectivity of Zn-Ade-TCPE for benzene / cyclohexane in the liquid phase.

[0034] Figure 16 The substances adsorbed by the Zn-Ade-TCPE sample after five consecutive adsorption experiments. 1 H NMR spectrum.

[0035] Figure 17 The data are the adsorption isotherms of Zn-Ade-TCPE on benzene in cyclohexane in the liquid phase (the data are the average values ​​of three sets of experiments).

[0036] Figure 18 The graph shows the change in benzene concentration in cyclohexane over time during liquid-phase adsorption (inset: enlarged view of the data from the last 200 minutes). Detailed Implementation

[0037] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0038] Example 1: Preparation of Zn-Ade-TCPE

[0039] Zn(NO3)2·6H2O (2.5 mmol), H4TCPE (500 mg, 1.0 mmol) and adenine (200 mg, 1.5 mmol) were dissolved in a mixture of 40 mL water and 40 mL N,N-dimethylacetamide (DMA). After ultrasonic treatment, the solids were completely dissolved. The solution was then transferred to a 100 mL autoclave and reacted in an oven at 120 °C for 24 h. After the reaction, the product Zn-Ade-TCPE crystalline sample was separated by centrifugation and washed with DMA, then soaked in methanol solvent, and the solvent exchange was continued for 3-4 times. The exchanged crystalline sample was transferred to fresh methanol solvent. The SEM image of Zn-Ade-TCPE crystals prepared in Example 1 is shown in Figure 1 .

[0040] A single crystal sample with appropriate size and high crystallinity prepared in Example 1 was selected, and diffraction data were collected at 220 K using a single crystal diffractometer, and then the crystal structure was refined using structure analysis software SHELX. The specific crystal data are shown in Table 1.

[0041] The crystal data of Zn-Ade-TCPE are as follows:

[0042] The structure diagram of the Zn-Ade-TCPE crystal is shown in Figure 2 . In the structure of Zn-Ade-TCPE, there are chain units formed by coordination of Zn atoms with N atoms on the adenine ring, and the chain units are connected by deprotonated H4TCPE to form a three-dimensional framework structure.

[0043] The three-dimensional framework structure of Zn-Ade-TCPE has a hierarchical pore structure, and the large pores and small pores are alternately connected to form an interlaced cavity structure. See Figure 3 for details. The interface of the large pore cavity is very narrow, about 4.25 x 6.73 Å, which allows relatively thin benzene molecules to pass through, and inhibits the entry of relatively thick cyclohexane into the cavity, so as to realize the high selective separation of the two.

[0044] Figure 4 The thermogravimetric analysis (TGA) diagram of Zn-Ade-TCPE shows that Zn-Ade-TCPE has high thermal stability, and no obvious collapse of the MOF framework structure is observed before 350 °C. The mass loss before 200 °C is speculated to be the removal of the guest molecules coordinated in the pores.

[0045] Figure 5 The powder diffraction diagram of Zn-Ade-TCPE shows that the structure of Zn-Ade-TCPE has good stability, and still maintains good crystallinity and no obvious collapse of the structure after adsorption / penetration and various treatments.

[0046] Example 2 Static vapor adsorption tests

[0047] Before the adsorption tests, the sample obtained in Example 1, which was soaked in methanol, was dried at 60 °C and degassed at 120 °C for 8 h to obtain a desolvated dry sample of the material. 50-60 mg of the activated sample was loaded into an adsorption tube and connected to the adsorption instrument for the adsorption isotherm test and the adsorption cycle test.

[0048] The adsorption isotherms of benzene and cyclohexane on Zn-Ade-TCPE were measured at 298 K, respectively. The results are shown in Figure 6 The adsorption capacity of Zn-Ade-TCPE for benzene is high throughout the pressure range, while the adsorption of cyclohexane is almost negligible (see Figure 6 a). At 12.4 kPa (0.95 P / P 0 , P 0= 13.019 kPa), the adsorption of cyclohexane is only 0.23 mmol / g, which only produces adsorption on the external surface, in contrast, the adsorption of benzene increases sharply at low pressure (<0.01 kPa) (see Figure 6 b). At 8.2 Pa (6.4 x 10 −4 P / P 0 , P 0= 12.695 kPa), the adsorption of benzene reaches 2.49 mmol / g, and gradually increases to 3.79 mmol / g as the pressure approaches the saturation pressure (12.2 kPa, 0.95 P / P 0 ) of benzene. This indicates that Zn-Ade-TCPE has a high affinity for benzene and strong interactions with benzene molecules. The very low adsorption of cyclohexane indicates that Zn-Ade-TCPE has very weak interaction forces for cyclohexane.

[0049] In addition, the benzene adsorption of Zn-Ade-TCPE is completely reversible, and the benzene adsorption isotherm was measured five times by reactivating the MOF sample by vacuum heating at 120 °C in each cycle, and the adsorption of benzene remains essentially unchanged (see Figure 7 ). The results of the static vapor adsorption experiment show that Zn-Ade-TCPE has high potential in the separation of benzene and cyclohexane vapor.

[0050] Example 3 Dynamic breakthrough experiment

[0051] Before conducting the breakthrough test, the sample obtained in Example 1, which had been immersed in methanol, was dried at 60°C and degassed at 120°C for 8 hours to obtain a desolventized dry sample. 30-200 mg of this activated sample was placed in a breakthrough tube and connected to the breakthrough device for testing.

[0052] A nitrogen stream (partial pressure ratio) containing approximately 0.51% benzene and approximately 4.75% cyclohexane vapor was passed through a quartz column packed with a Zn-Ade-TCPE sample. The cyclohexane vapor immediately penetrated the Zn-Ade-TCPE column, but the benzene had a long residence time of approximately 520 min / g (see [link to article]). Figure 8 The corresponding benzene adsorption capacity was approximately 1.18 mmol / g. Gas chromatography-flame ionization detector (GC-FID) analysis showed that the purity of cyclohexane in the outlet gas exceeded 99.99% at 300 min / g (see [reference]). Figure 9 a, b).

[0053] Even when the concentrations of benzene and cyclohexane vapors in the inlet gas changed, even decreasing to the ppm level, similar breakthrough curves were still obtained (see...). Figure 10 a, b). At benzene and cyclohexane concentrations of 100 and 900 ppm, respectively, the Zn-Ade-TCPE sample still captured trace amounts of benzene vapor, with a capture capacity as high as approximately 1.34 mmol / g (breakthrough begins at approximately 15000 min / g), but adsorbed almost no cyclohexane (see [reference needed]). Figure 10 b). GC-FID analysis showed that benzene was undetectable in the outlet gas before 5000 min / g, after which the benzene concentration increased slightly, from 0.07 ppm to 0.21 ppm at 6000 min / g to 12000 min / g, and to 6.16 ppm at 13000 min / g (see [link to analysis]). Figure 11 a, b and Figure 12 Before reaching 12000 min / g, the purity of cyclohexane in the outlet gas was consistently above 99.97%. Adsorbed benzene (containing a small amount of cyclohexane) could be recovered by heating the Zn-Ade-TCPE sample in a nitrogen stream at 120°C (see...). Figure 13 These results confirm that Zn-Ade-TCPE can effectively separate real vapor mixtures of benzene and cyclohexane at room temperature, even under low pressure.

[0054] Example 4 Liquid phase separation experiment

[0055] Since the separation of benzene and cyclohexane is mainly carried out in the liquid phase, the performance of Zn-Ade-TCPE in the separation of benzene / cyclohexane in the liquid phase was tested.

[0056] Before conducting the liquid phase separation experiment, the sample obtained in Example 1, which was immersed in methanol, was dried at 60°C and degassed at 120°C for 8 hours to obtain a desolventized dry sample of the material. The Zn-Ade-TCPE sample was placed in a liquid mixture of benzene and cyclohexane with a volume ratio of 1:1, 1:10, and 1:20.

[0057] After shaking at room temperature for 6 hours, the MOF sample was collected by filtration and dried at 40°C to remove residual liquid. The MOF-adsorbed molecular guests were extracted with deuterated methanol and then subjected to further processing. 1 The results obtained from H NMR spectroscopy analysis are as follows: Figure 14 As shown, a strong peak is observed at 7.3 ppm, corresponding to the hydrogen atom of benzene, while the peak of the cyclohexane hydrogen atom at 1.5 ppm is almost undetectable. The estimated molar ratio of benzene to cyclohexane adsorbed at a 1:1 ratio is approximately 262. The adsorption selectivity of benzene / cyclohexane in the liquid phase is calculated using the formula (q1 / C2) / (q2 / C1), where q1 and q2 are the adsorption capacities of benzene and cyclohexane (in mmol / g), respectively, and C1 and C2 are their molar fractions in the liquid mixture, which are 216, 723, and 1027, respectively (see [reference needed]). Figure 15 This means that for mixtures with low benzene content, the Zn-Ade-TCPE sample even provides higher benzene / cyclohexane adsorption selectivity. The adsorption selectivity results described above represent the highest benzene / cyclohexane liquid-phase adsorption selectivity achieved under similar conditions with a solid adsorbent.

[0058] Five consecutive liquid-phase adsorption experiments were conducted using the same Zn-Ade-TCPE sample. The results showed that the Zn-Ade-TCPE sample maintained good adsorption selectivity for benzene / cyclohexane after repeated use. (See figure) Figure 16 .

[0059] Example 5: Separation and testing of trace benzene in liquid phase cyclohexane

[0060] To confirm the ability of the Zn-Ade-TCPE sample to capture trace amounts of benzene in liquid-phase cyclohexane, the following experiment was conducted to obtain the liquid-phase adsorption isotherm of benzene at room temperature. The Zn-Ade-TCPE sample was placed in cyclohexane with an initial benzene content ranging from 10 to 1000 ppm (mass ratio), with an adsorbent-to-solvent ratio of 1 g / L. After 12 hours of shaking to reach equilibrium, the benzene content in the mixture was analyzed by gas chromatography-flame ionization detector (GC-FID), and the adsorption capacity was calculated. Figure 17As shown, the adsorption capacity of benzene increases sharply at a content lower than 100 ppm and reaches a plateau value of 226 mg / g (2.90 mol / g) at about 280 ppm. This liquid benzene adsorption capacity is close to the benzene vapor adsorption capacity at low pressure, for example, 229 mg / g (2.93 mol / g) at a pressure close to 28 Pa (see Table 1). The adsorption capacity of benzene on Zn-Ade-TCPE is much higher than that on other porous materials, such as activated carbon (0.5 mol / g) and zeolite 5A (1.1 mol / g) (see Table 1). Figure 6 b), which indicates that the pores of Zn-Ade-TCPE are not blocked by liquid cyclohexane.

[0061] To further verify the feasibility of Zn-Ade-TCPE for removing trace benzene in liquid cyclohexane, a Zn-Ade-TCPE sample was placed in a liquid cyclohexane containing 1000 ppm benzene, with a sorbent-to-solvent ratio of 10 g / L (sorbent excess), and the benzene content was monitored while the mixture was shaken. The benzene content decreased rapidly to 24 ppm within the first 2 hours, and then further decreased to 7.5 ppm within the following 4 hours (see Fig. 2b), corresponding to a benzene removal rate of up to 99.3%. Figure 18

[0062] After 10 g of Zn-Ade-TCPE was used to perform the adsorption-desorption process for 1 L of cyclohexane with a purity of 99.9% (containing benzene as an impurity), the cyclohexane was deeply purified to a purity of >99.999%. Similar liquid adsorption experiments were also performed on a 1 :99 benzene / cyclohexane liquid mixture, with a sorbent-to-solvent ratio of 100 g / L. After 6 hours of adsorption, the benzene concentration decreased to 0.047% (>95% removal), resulting in cyclohexane with a purity of >99.95%. These results confirm the high performance of Zn-Ade-TCPE in the separation of liquid benzene / cyclohexane, especially in removing trace benzene from cyclohexane.

[0063] Separation mechanism:

[0064] Cyclohexane molecules cannot enter the large and small pores in the Zn-Ade-TCPE structure, but benzene molecules can. This molecular sieving effect originates from the unique interpenetrated cavity structure of Zn-Ade-TCPE and the subtle differences in the molecular structures of benzene and cyclohexane. The cyclohexane molecule is non-planar and significantly thicker than the planar benzene molecule, making it more difficult for the cyclohexane molecule to pass through the narrow gaps between the larger pores in Zn-Ade-TCPE than for the planar benzene molecule. In addition, for each adsorbed benzene molecule, there are multiple weak C-H···π, C-H···O (carboxylic acid oxygen atom), and / or C-H···N (adenine N atom) interactions with the framework and adjacent adsorbed benzene molecules. That is, there are abundant weak interactions between the structural framework of Zn-Ade-TCPE and the Bz molecules, which should be the reason why Zn-Ade-TCPE exhibits a high Bz adsorption capacity even at low pressure.​

Claims

1. An application of a metal-organic framework material in the removal of trace benzene from cyclohexane, characterized in that: The metal-organic framework material is a Zn(II)-based metal-organic framework material, Zn-Ade-TCPE, constructed from mixed ligands, with the chemical formula C2. 116 H 96 N 14 O 30 Zn7 is a pale yellow, blocky crystalline material prepared by a solvothermal reaction of the organic ligand H4TCPE, adenine, and Zn(NO3)2·6H2O. H4TCPE is 4,4',4'',4'''-(ethylene-1,1,2,2-tetramethyl)tetrabenzoic acid, with the molecular formula C. 30 H 20 O8.

2. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The molar ratio of adenine, H4TCPE and Zn(NO3)2·6H2O is 1.5:1:2.

5. The volume ratio of N,N-dimethylacetamide (DMA) and water in the mixed solvent of the solvothermal reaction is 1:

1. The volume ratio of solvent used per millimole of organic ligand H4TCPE is 1:60 mL.

3. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The solvothermal reaction temperature was 120℃, and the reaction time was 24 hours.

4. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The activation method of the Zn-Ade-TCPE material is as follows: the sample is washed with N,N-dimethylacetamide (DMA) solvent, then immersed in methanol solvent, and solvent exchange is performed for 3-4 times. The sample immersed in methanol is then dried at 60°C and degassed at 120°C for 8 hours to obtain a desolventized dry sample of the material.

5. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The Zn-Ade-TCPE has a three-dimensional framework structure, which includes chain units formed by coordination of Zn atoms with N atoms on the adenine ring. The chain units are connected by deprotonated H4TCPE to form the three-dimensional framework structure. In the three-dimensional framework structure of Zn-Ade-TCPE, there are two types of cavities, which are connected by extremely narrow openings, forming a slit-like structure.

6. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The metal-organic framework material can achieve the removal of trace amounts of benzene from cyclohexane in both the gas and liquid phases.

7. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The metal-organic framework material can be recycled.

8. The application of the metal-organic framework material according to claim 1 in the removal of trace benzene from cyclohexane, characterized in that: The purity of cyclohexane after Zn-Ade-TCPE separation reached over 99.9%.

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