A eutectic material based on hetero[4]arene and its preparation method and application

Abstract

The present invention relates to a eutectic material based on hetero[4]arene and a preparation method and application thereof, and belongs to the field of adsorption materials. A eutectic material based on hetero[4]arene, with hetero[4]arene as an electron donor and 1,2,4,5-tetracyanobenzene as an electron acceptor, the electron donor and the electron acceptor are combined in a molar ratio of 1:1 to form a eutectic material based on hetero[4]arene. The eutectic preparation process provided by the present invention is simple and efficient, the eutectic produced has good stability, and has good adsorption and separation effect on chemical industry products. For example, the separation process for benzene / cyclohexane and toluene / pyridine mixed steam is simple to operate and has low equipment requirements; the separation process does not require distillation operation, has low energy consumption, saves energy, and reduces the production cost of benzene; the crystal material used has high stability, can be recycled, and the separation effect will not be reduced.

Description

Technical Field

[0001] The present invention relates to a eutectic material based on hetero[4]arene and a preparation method and application thereof, belonging to the field of adsorption materials. Background Art

[0002] Cocrystal engineering, which features non-covalent assembly of simple constituent units, has attracted great interest and has become an effective and versatile approach to construct functional materials, especially for the manufacture of novel and multifunctional materials, due to the cooperative strategies in different constituent units. Typically, organic cocrystals are assembled from two or more different chemical species through non-covalent intermolecular interactions, such as charge transfer (CT) interactions, π-π stacking, halogen bonds, and hydrogen bonds. Despite the fascination in this field, the development of functional cocrystals has actually been slow, which may be attributed to the structural mismatch of different component compounds, the ambiguous mechanism of cocrystals, and the fact that the overall properties may change in unpredictable ways. The patent specification with publication number CN 115894160 A discloses a method for achieving polar phase transition in organic cocrystals by introducing a third element. The method places a donor molecule, an acceptor molecule, and a third element material in an organic solvent to obtain a high-quality organic ternary crystal with polar phase transition, but its construction method is difficult and has no substantial application. The patent specification with publication number CN 116102460 A discloses a class of full-spectrum organic eutectic materials based on tetracyanobenzoquinone. The full-spectrum organic eutectic materials are formed by non-covalent assembly of organic acceptor molecule tetracyanobenzoquinone and donor molecule benzidine or aniline, and show excellent performance in photothermal conversion and water evaporation. However, they cannot purify or adsorb organic vapors, and their application in the chemical industry is weak.

[0003] The separation of benzene and cyclohexane is an important industrial process and is considered one of the most challenging tasks in the chemical industry. Benzene is widely used in synthetic chemistry, such as the production of dyes, plastics, and drugs, and cyclohexane is not only a raw material for the production of cyclohexanol and cyclohexanone, but is also used in varnishes and oils. In the production process of cyclohexane, it is mainly obtained by the catalytic hydrogenation reaction of benzene. However, because the catalytic hydrogenation reaction is incomplete, benzene cannot be completely converted into cyclohexane. Therefore, in order to obtain high-purity cyclohexane, it is crucial to separate the unreacted benzene from the reaction solution. However, the small difference of 0.7K between the boiling points of benzene (353.2K) and cyclohexane (353.9K) poses great challenges to various distillation and purification processes. Currently, extraction and azeotropic distillation have been used for industrial separation of benzene and cyclohexane. The patent specification with publication number CN 105601462 A discloses a method for purifying high-purity benzene. An adsorption column is prepared by molecular imprinting technology for adsorption. Relying on its specific adsorption capacity, thiophene in the benzene solution can be effectively removed. No solvent is required in the melt crystallization purification process, which avoids the contamination of the product by the solvent and reduces the solvent recovery process. The purity of the purified product is high. The patent specification with publication number CN 115651203 A discloses a supramolecular crystal framework material based on BN coordination bonds, its preparation method and application. The material has an electron-rich cavity, can selectively adsorb benzene in a benzene / cyclohexane mixed gas, and has good physical and chemical stability. The patent specification with publication number CN102617262A discloses an energy-saving process for separating cyclohexane-cyclohexene-benzene, which is an energy-saving process for obtaining cyclohexane, cyclohexene and benzene from a mixed raw material containing cyclohexane, cyclohexene and benzene by extractive distillation, respectively. The traditional four-tower, two-time extractive distillation process is changed to a single extractive distillation process, and the separation process of cyclohexene from cyclohexane and cyclohexene from benzene is completed while completing the cyclohexane / benzene extractive distillation separation, thereby reducing production costs. At present, these methods for separating benzene and cyclohexane are complicated in process operation, and both distillation and extraction are accompanied by a large amount of energy consumption, resulting in high operating costs.

[0004] The separation of toluene and pyridine is one of the most challenging tasks in the chemical industry. Pyridine is an important solvent and catalyst, which is widely used in petrochemical, agrochemical and pharmaceutical industries. Toluene can be used not only as a solvent, fuel additive and dealkylation reactant, but also in the synthesis of important chemical products such as dyes, fragrances, explosives and pharmaceutical intermediates. In industry, toluene is mainly obtained from coal and petroleum through catalytic reforming, hydrocarbon pyrolysis and coking. However, there are always a small amount of heterocyclic compounds such as pyridine remaining. Therefore, it is very important to separate high-purity toluene and pyridine from a mixture of toluene and pyridine. However, the boiling points of pyridine (388.3K) and toluene (383.8K) are very close. The separation of toluene from pyridine by distillation is accompanied by huge energy consumption, high cost, and it is difficult to obtain high-purity toluene. In addition, molecular sieves can achieve the separation of the two by adsorption separation. However, this process requires a high-purity desorbent, which is easy to cause environmental pollution. Therefore, it is very necessary to develop a low-cost and easy-to-operate efficient method to separate toluene and pyridine. The patent with publication number CN 214681644U discloses a device for extracting high-purity pyridine from crude toluene, including a connecting pipe and a reaction tower. The crude toluene pump and the crude toluene tank are connected in sequence in the reaction tower through the connecting pipe, and by changing the original separation and extraction system, not only the extraction effect of pyridine in crude toluene is improved, but also the energy consumption of the production system is reduced. An article published in the 11th issue of Volume 40 of Chemical Engineering in 2012 discloses a method for separating a small amount of pyridine from toluene by continuous extraction and distillation to obtain a toluene product with higher purity. According to the characteristics that pyridine is miscible with water and toluene is azeotropic with water, water is selected as the extractant. In view of the partial miscibility of this system, the NRTL thermodynamic method is used to investigate the effects of the feed ratio of the extractant to the raw material, the ratio of the condensation amount of the tower top steam to the raw material feed, and the feed position of the extractant to the raw material on the separation effect, so as to obtain the best process operation conditions. At present, these methods for separating toluene and pyridine are complicated in process operation, and both distillation and extraction are accompanied by a large amount of energy consumption, resulting in high operating costs. Although the device for treating organic industrial wastewater with cavitation technology can effectively separate toluene, its operation is cumbersome and expensive. Summary of the invention

[0005] The present invention provides a eutectic material based on hetero[4]arene, which can be effectively applied to the adsorption of toluene and benzene.

[0006] A eutectic material based on hetero[4]arene, characterized in that: hetero[4]arene is used as an electron donor, 1,2,4,5-tetracyanobenzene is used as an electron acceptor, and the electron donor and the electron acceptor are combined in a molar ratio of 1:1 to form a eutectic material based on hetero[4]arene, wherein:

[0007] The hetero[4]arene has the following general formula I:

[0008]

[0009] The eutectic material of the present invention is a monoclinic C crystal system, the space group is Fdd2, and the unit cell parameters of the eutectic material are: a=26.7226(9), b=35.7156(12), c=11.5081(4), α=90, β=90, γ=90.

[0010] The hetero[4]arene of the present invention is prepared by the following method:

[0011] Step 1: Under nitrogen protection, ethyl bromide and 2,6-dihydroxynaphthalene in a molar ratio of 10:1 are placed in a saturated sodium hydroxide methanol solution, and stirred at 60-65° C. for reaction; after the reaction is completed, the mixture is cooled to room temperature, filtered, washed, and dried to obtain an intermediate product;

[0012] Step 2: The intermediate product, 1,3-dimethoxybenzene and polyformaldehyde in a molar ratio of 1:1:2 are dissolved in chloroform, trifluoroacetic acid is added to catalyze the reaction during stirring at room temperature, and then heated to 60°C with stirring. After the reaction is complete and cooled to room temperature, a saturated sodium bicarbonate solution is added to quench the reaction. After separation, the hetero[4]aromatic macrocyclic compound is obtained by column chromatography.

[0013] Preferably, the step 1: putting ethyl bromide and 2,6-dihydroxynaphthalene in a molar ratio of 10:1 into a round-bottom flask, preparing a saturated sodium hydroxide methanol solution, and slowly pouring the sodium hydroxide methanol solution into the round-bottom flask after the temperature of the sodium hydroxide methanol solution drops, the reaction process requires nitrogen gas protection, heating to 60-65° C. and stirring the reaction; after the reaction is completed, cooling to room temperature, filtering out excess liquid, and then rinsing with methanol solvent 2-3 times, placing in a vacuum drying oven and heating to 40-50° C. to obtain an intermediate product after drying.

[0014] Preferably, in step 2, the column chromatography eluent is petroleum ether or dichloromethane.

[0015] Preferably, the hetero[4]arene macrocyclic compound obtained in step 2 is activated by removing solvent molecules by heating.

[0016] Preferably, the activation temperature is not less than 120° C., and the activation time is not less than 9 hours.

[0017] Another object of the present invention is to provide a method for preparing the above-mentioned hetero[4]arene-based eutectic material.

[0018] A method for preparing a eutectic material based on hetero[4]arene comprises placing hetero[4]arene and tetracyanobenzene in n-hexane at a molar ratio of 1:1, heating to boiling, adding n-hexane dropwise until all are dissolved, storing the solution at 0°C overnight, filtering and collecting the precipitated crystals, drying the obtained crystals in a vacuum at 50°C, and activating at 120°C for 9 hours to obtain an orange powder eutectic material of hetero[4]arene.

[0019] Another object of the present invention is to provide the use of the above-mentioned hetero[4]arene-based eutectic material as a benzene or toluene adsorbent.

[0020] A method for separating benzene and cyclohexane, characterized in that: a eutectic material based on hetero[4]arene is placed in a mixed vapor atmosphere of cyclohexane and benzene at a temperature less than 80°C, so that all benzene is adsorbed by the eutectic material.

[0021] Furthermore, the preferred temperature is 25 to 35°C.

[0022] The method comprises a step of regenerating the adsorbent, specifically: removing the mixture of benzene and cyclohexane adsorbed on the surface of the hetero[4]arene-based eutectic material by vacuum heating or reduced pressure heating at a temperature below 80°C, thereby achieving regeneration of the hetero[4]arene-based eutectic material;

[0023] Alternatively, at 80 to 100° C., heating desorption is used to remove the benzene adsorbed and complexed by the hetero[4]arene-based eutectic material, while achieving regeneration of the hetero[4]arene-based eutectic material.

[0024] Furthermore, preferably at 70 to 80°C, vacuum heating or reduced pressure heating is used to remove the mixture of benzene and cyclohexane adsorbed on the surface of the hetero[4]arene-based eutectic material, thereby achieving regeneration of the hetero[4]arene-based eutectic material.

[0025] A method for separating toluene and pyridine comprises placing the hetero[4]arene-based eutectic material in a mixed vapor atmosphere of pyridine and toluene at a temperature less than 80° C., so that all the toluene is adsorbed by the eutectic material.

[0026] Furthermore, the preferred temperature is 25 to 35°C.

[0027] The method comprises a step of regenerating the adsorbent, specifically: removing the mixture of toluene and pyridine adsorbed on the surface of the hetero[4]arene-based eutectic material by vacuum heating or reduced pressure heating at a temperature below 80°C, thereby achieving the regeneration of the hetero[4]arene-based eutectic material;

[0028] Alternatively, at 80 to 100° C., heating desorption is used to remove toluene adsorbed and complexed by the hetero[4]arene-based eutectic material, while achieving regeneration of the hetero[4]arene-based eutectic material.

[0029] Furthermore, preferably at 70 to 80° C., vacuum heating or reduced pressure heating is used to remove the toluene and pyridine mixture adsorbed on the surface of the hetero[4]arene-based eutectic material, thereby achieving regeneration of the hetero[4]arene-based eutectic material.

[0030] The beneficial effects of the present invention are as follows: compared with the prior art, the eutectic preparation process provided by the present invention is simple and efficient, the eutectic produced has good stability, and has good adsorption and separation effects on chemical industry products. For example, the separation process for benzene / cyclohexane and toluene / pyridine mixed vapor is simple to operate and has low equipment requirements; the separation process does not require distillation operation, has low energy consumption, saves energy, and reduces the production cost of benzene; the crystal material used is highly stable and can be recycled, and the separation effect will not be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the H NMR spectrum of hetero[4]arene compounds.

[0032] Figure 2 This is the carbon spectrum of hetero[4]arene compounds.

[0033] Figure 3 Mass spectrum of hetero[4]arene compounds.

[0034] Figure 4 PXRD pattern simulated from hetero[4]arene crystals.

[0035] Figure 5 This is the thermogravimetric curve of hetero[4]arene compounds.

[0036] Figure 6 This is the single crystal structure of a hetero[4]arene compound.

[0037] Figure 7 This is the NMR spectrum of the co-crystal material based on hetero[4]arene;

[0038] Figure 8 Thermogravimetric diagram of the eutectic material based on hetero[4]arene;

[0039] Fig. 9 Heat flow diagram for hetero[4]arene-based eutectic materials;

[0040] Fig.10 Diffuse reflectance spectra of hetero[4]arene-based cocrystal materials;

[0041] Fig.11 The PXRD pattern of the co-crystal material based on hetero[4]arene after adsorption of benzene and cyclohexane;

[0042] Fig.12 The selective adsorption effect of hetero[4]arene-based cocrystal materials on a mixture of benzene and cyclohexane;

[0043] Fig.13 for the cyclability of hetero[4]arene-based eutectic materials;

[0044] Fig.14 PXRD pattern of the co-crystal material based on hetero[4]arene after adsorption of toluene and pyridine;

[0045] Fig.15 The selective adsorption effect of hetero[4]arene-based cocrystal materials on toluene and pyridine mixtures;

[0046] Fig.16 Cyclic ability of hetero[4]arene-based eutectic materials. DETAILED DESCRIPTION

[0047] The following non-limiting embodiments may enable a person skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0048] The test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0049] One of the specific implementations:

[0050] In order to solve the defects of benzene and cyclohexane separation technology, such as high energy consumption, complicated process, and the need to use high-purity desorbent, a method for separating benzene and cyclohexane is provided, which uses a eutectic material based on hetero[4]arene to adsorb and separate a mixture of benzene and cyclohexane, with low energy consumption, simple process, and obvious color change. In addition, the method can be recycled.

[0051] The hetero[4]arene-based eutectic material obtained by recrystallization can be activated by removing solvent molecules by heating. Preferably, the activation temperature is not less than 120° C. and the activation time is not less than 9 hours. The activated hetero[4]arene-based eutectic material can be directly used for the adsorption separation of cyclohexane and benzene mixture.

[0052] The specific steps of using a hetero[4]arene-based eutectic material to adsorb and separate a mixture of benzene and cyclohexane are as follows: placing the hetero[4]arene-based eutectic material in a mixed vapor atmosphere of cyclohexane and benzene at a temperature less than 80°C. The adsorption time can vary with factors such as the sample amount and the proportion of benzene in the mixture. During the adsorption process, the hetero[4]arene-based eutectic material will undergo a change in crystal form. Due to the multiple non-covalent bond interactions between CH-π, CH-O, and CH-N, benzene in the mixed vapor will form a host-guest complex with the hetero[4]arene-based eutectic material, and the stoichiometric ratio of the eutectic polymer is 1:1:1.

[0053] After the hetero[4]arene-based eutectic material is completely adsorbed in the mixed vapor atmosphere of cyclohexane and benzene, the hetero[4]arene-based eutectic material is taken out, and then vacuum heating or reduced pressure heating can be used to remove the benzene and cyclohexane mixture adsorbed on the surface of the hetero[4]arene-based eutectic material. Preferably, the temperature of the vacuum heating or reduced pressure heating is less than 80°C. The heating time can be adjusted according to the sample amount. Under the condition of less than 80°C, the host-guest complex still exists stably, and the cyclohexane and benzene mixture adsorbed on the surface can be gradually removed. By removing the mixed vapor adsorbed on the surface, the purity of the benzene separated by adsorption can be further improved.

[0054] The benzene adsorbed and complexed by the hetero[4]arene-based eutectic material can be removed by heating and desorption, and the hetero[4]arene-based eutectic material can be regenerated at the same time. The desorption time can be adjusted according to the sample amount. Preferably, the heating temperature is 80 to 100°C. At this temperature, the eutectic polymer is unstable, and the adsorbed benzene molecules will gradually be released, while the hetero[4]arene-based eutectic material is stable, and only the crystal form changes during the desorption process. After the desorption is completed, the regenerated hetero[4]arene-based eutectic material is obtained, which can continue to be used for the adsorption separation of cyclohexane and benzene for the next cycle.

[0055] Specific implementation method 2:

[0056] In order to solve the defects of toluene and pyridine separation technology, such as high energy consumption, complicated process and the need to use high-purity desorbent, a method for separating toluene and pyridine is provided, which uses a eutectic material based on hetero[4]arene to adsorb and separate a mixture of toluene and pyridine, with low energy consumption, simple process and obvious color change. In addition, the method can be recycled.

[0057] The hetero[4]arene-based eutectic material obtained by recrystallization can be activated by removing solvent molecules by heating. Preferably, the activation temperature is not less than 120° C. and the activation time is not less than 9 hours. The activated hetero[4]arene-based eutectic material can be directly used for the adsorption separation of pyridine and toluene mixture.

[0058] The specific steps of using the hetero[4]arene-based eutectic material to adsorb and separate a mixture of toluene and pyridine are as follows: placing the hetero[4]arene-based eutectic material in a mixed vapor atmosphere of pyridine and toluene at a temperature less than 80° C. The adsorption time can be changed with changes in factors such as the sample amount and the proportion of toluene in the mixture. During the adsorption process, the hetero[4]arene-based eutectic material will undergo a change in crystal form.

[0059] After the hetero[4]arene-based eutectic material is completely adsorbed in the mixed vapor atmosphere of pyridine and toluene, the hetero[4]arene-based eutectic material is taken out, and then vacuum heating or reduced pressure heating can be used to remove the toluene and pyridine mixture adsorbed on the surface of the hetero[4]arene-based eutectic material. Preferably, the temperature of the vacuum heating or reduced pressure heating is less than 80°C. The heating time can be adjusted according to the sample amount. Under the condition of less than 80°C, the host-guest complex still exists stably, while the pyridine and toluene mixture adsorbed on the surface can be gradually removed. By removing the mixed vapor adsorbed on the surface, the purity of the toluene separated by adsorption can be further improved.

[0060] The toluene adsorbed and complexed by the hetero[4]arene-based eutectic material can be removed by heating and desorption, and the hetero[4]arene-based eutectic material can be regenerated at the same time. The desorption time can be adjusted according to the sample amount. Preferably, the heating temperature is 80 to 100°C. At this temperature, the eutectic compound is unstable, and the adsorbed toluene molecules will gradually be released, while the hetero[4]arene-based eutectic material is stable, and only the crystal form changes during the desorption process. After the desorption is completed, the regenerated hetero[4]arene-based eutectic material is obtained, which can continue to be used for the adsorption and separation of toluene and pyridine for the next cycle.

[0061] In the following examples, the hetero[4]arene compounds were prepared by the following method: Preparation of hetero[4]arene compounds

[0062]

[0063] The first step of the reaction: put 6g of ethyl bromide and 3.6g of 2,6-dihydroxynaphthalene into a round-bottom flask, prepare 50ml of saturated sodium hydroxide methanol solution, and slowly pour the sodium hydroxide methanol solution into the round-bottom flask after the temperature drops to 25°C. The reaction process requires nitrogen gas protection, and the mixture is heated to 65°C and stirred for reaction. After the reaction is completed, cool to room temperature, filter out excess liquid, rinse with methanol solvent 2-3 times, place in a vacuum drying oven, heat to 40°C, and then dry to obtain the intermediate product;

[0064] The yield of the intermediate product in Example 1 was tested to be 95%.

[0065] The second step reaction: 2g of the intermediate product, 1g of 1,3-dimethoxybenzene and 0.6g of polyformaldehyde were dissolved in 200ml of chloroform. During stirring at room temperature, 10ml of trifluoroacetic acid was added to catalyze the reaction. The mixture was then heated to 60°C and stirred. After the reaction was complete and cooled to room temperature, 50ml of saturated sodium bicarbonate solution was added to quench the reaction. After separation, the hetero[4]aromatic hydrocarbons were obtained by column chromatography, with dichloromethane as the eluent.

[0066] The yield of hetero[4]arene product in Example 1 was tested to be 30%.

[0067] The product characterization data prepared in this example are as follows:

[0068] 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s, 2H), 4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).The 13 C NMR (400MHz, CD2Cl2, 293K) δ (ppm): 156.32, 152.75, 130.02, 128.78, 124.21, 122.72, 120.73, 116.87, 95.17, 66.53, 66.53, 56.18, 54.26, 54.04, 53.83, 53.61, 53.39, 24.11, 15.50. High resolution mass spectrometry value m / z: 755.2839, corresponding to [hetero[4]arene-H] - . Melting range: 240~241℃.

[0069] The PXRD test results are as follows Figure 4 As shown, the obtained hetero[4]arene materials have good crystallinity.

[0070] TG test results are as follows Figure 5 As shown, the obtained hetero[4]arene materials have good stability.

[0071] Single crystal structure and related parameters such as Figure 6 As shown, the obtained hetero[4]arene has a good crystal structure.

[0072] Example 1

[0073] Preparation of cocrystal material based on hetero[4]arene: Weigh 2 g of hetero[4]arene and 0.5 g of tetracyanobenzene into 20 mL of n-hexane, heat to boiling, add n-hexane dropwise until all dissolved, store the solution at 0°C overnight, collect the precipitated crystals by filtration, dry the obtained crystals in vacuo at 50°C, activate at 120°C for 9 hours, and obtain an orange powder, recorded as 1-TCNB.

[0074] The product characterization data prepared in this example are as follows:

[0075] 1-TCNB, 1H NMR (500MHz, CD2Cl2, 293K) (ppm): 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s, 2H) ,4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0076] The PXRD test results are as follows Figure 1 As shown, the obtained hetero[4]arene-based co-crystal material has good crystallinity.

[0077] Example 2

[0078] Adsorption of hetero[4]arene-based eutectic materials on single benzene or cyclohexane: Take two 20mL culture bottles, add 1mL of benzene and 1mL of cyclohexane respectively, named 1-TCNB@Bz and 1-TCNB@Cy, take 200mg of the hetero[4]arene-based eutectic material prepared in Example 1 and place it in two 5mL open culture bottles, place the two open 5mL culture bottles in two 20mL culture bottles respectively, seal the 20mL culture bottles, and place them in a 25℃ water bath for 30 hours.

[0079] The product characterization data prepared in this example are as follows:

[0080] 1-TCNB@Bz, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 7.35 (s, 6H), 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0081] 1-TCNB@Cy, 1H NMR (500MHz, CD2Cl2, 293K) (ppm): 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s, 2H) ,4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0082] 1 H NMR results showed that the hetero[4]arene-based cocrystal material adsorbed benzene in a stoichiometric ratio of 1:1:1, but did not adsorb cyclohexane.

[0083] The PXRD test results are as follows Figure 1 As shown, compared with the PXRD spectrum of the initially activated hetero[4]arene-based eutectic material, the PXRD spectrum of the hetero[4]arene-based eutectic material after being placed in benzene vapor for a period of time changes, which indicates that its unit cell parameters have changed, meaning that benzene has been adsorbed into the hetero[4]arene-based eutectic material; the spectrum of the hetero[4]arene-based eutectic material after being placed in cyclohexane vapor for a period of time changes very little, indicating that its unit cell parameters have almost not changed, meaning that the hetero[4]arene-based eutectic material has no adsorption capacity for cyclohexane.

[0084] Example 3

[0085] Adsorption of a 1:1 mixture of benzene and cyclohexane by the eutectic material based on hetero[4]arene: Take a 20mL culture bottle, add 0.5mL of benzene and 0.5mL of cyclohexane, named 1-TCNB@Bz / Cy, take 200mg of the eutectic material based on hetero[4]arene prepared in Example 1 and place it in a 5mL open culture bottle, place the open 5mL culture bottle in the above 20mL culture bottle, seal the 20mL culture bottle, place it in a 25℃ water bath for 40 hours, and place the obtained powder in a 50℃ vacuum oven for 30 minutes.

[0086] The product characterization data prepared in this example are as follows:

[0087] 1-TCNB@Bz / Cy, 1H NMR (500MHz, CD2Cl2, 293K) (ppm): 7.35 (s, 6H), 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0088] exist 1 Only the signal of hydrogen atoms corresponding to benzene was found in the H NMR spectrum, which indicates that the cocrystal material based on hetero[4]arene can selectively adsorb benzene.

[0089] The PXRD test results are as follows Figure 1 As shown in the figure, compared with the PXRD spectrum of the initially activated hetero[4]arene-based cocrystal material, the PXRD spectrum of the hetero[4]arene-based cocrystal material after being placed in the mixed vapor of benzene and cyclohexane for a period of time changes, and the spectrum change is the same as that of 1-TCNB@Bz, which indicates that the hetero[4]arene-based cocrystal material can selectively adsorb benzene. The results of headspace gas chromatography are shown in Figure 2 As shown, the results indicate that the hetero[4]arene-based cocrystal material can selectively adsorb benzene with a selectivity of 100%.

[0090] Example 4

[0091] Regeneration of hetero[4]arene-based eutectic material: 200 mg of hetero[4]arene-based eutectic material saturated with benzene was heated in a vacuum oven at 120°C for 9 hours. The sample was designated as 1-TCNB-D.

[0092] The product characterization data prepared in this example are as follows:

[0093] 1-TCNB-D,1-TCNB@Cy, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s, 2H) ,4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0094] exist 1In the H NMR spectrum, it was found that the signal of the hydrogen atom corresponding to benzene had disappeared, which indicated that the cocrystal material based on hetero[4]arene had completed desorption and regeneration, and all benzene molecules had been released.

[0095] The PXRD test results are as follows Figure 1 As shown, compared with the PXRD spectrum of the initially activated hetero[4]arene-based eutectic material, the PXRD spectrum of the hetero[4]arene-based eutectic material after complete desorption changes very little, which indicates that the hetero[4]arene-based eutectic material has completed the desorption process and can be used for the next adsorption separation of benzene and cyclohexane.

[0096] Example 5

[0097] Recycling of hetero[4]arene-based eutectic material: Repeat Examples 3 and 4 with 200 mg of the regenerated hetero[4]arene-based eutectic material.

[0098] The results of headspace gas chromatography are as follows Figure 3 As shown, it is demonstrated that the cocrystal material based on hetero[4]arene can selectively adsorb benzene with a selectivity of up to 100%, and its selectivity does not decrease after being reused 5 times.

[0099] Example 6

[0100] Preparation of cocrystal material based on hetero[4]arene: Weigh 2 g of hetero[4]arene and 0.5 g of tetracyanobenzene into 20 mL of n-hexane, heat to boiling, add dichloromethane dropwise until all dissolved, store the solution at 0°C overnight, collect the precipitated crystals by filtration, dry the obtained crystals in vacuo at 50°C, activate at 120°C for 9 h, and obtain an orange powder, recorded as 1-TCNB.

[0101] The product characterization data prepared in this example are as follows:

[0102] 1-TCNB, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 8.24 (s, 2H), 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0103] The PXRD test results are as follows Figure 1 As shown, the obtained hetero[4]arene-based co-crystal material has good crystallinity.

[0104] Example 7

[0105] Adsorption of toluene or pyridine by the cocrystal material based on hetero[4]arene: Take two 20mL culture bottles, add 1mL toluene and 1mL pyridine respectively, and name them 1-TCNB@Tol and 1-TCNB@Py. Take 200mg of the cocrystal material based on hetero[4]arene prepared in Example 1 and place them in two 5mL open culture bottles respectively. Place the two open 5mL culture bottles in two 20mL culture bottles respectively. Seal the 20mL culture bottles and place them in a 25℃ water bath for 30h.

[0106] The product characterization data prepared in this example are as follows:

[0107] 1-TCNB@Tol, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 8.24 (s, 2H), 7.25 (t, J = 15Hz, 2H), 7.35 (s, 6H), 7 .24(d,J=10Hz,4H),7.17(d,J=10Hz,2H),7.15(t,J=15Hz,1H)6.85(d,J=10Hz,4H), 6.63(s,2H),5.71(s,2H),4.51(s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H ),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),2.34(s,3H),1.24(t,J=15Hz,12H).

[0108] 1-TCNB@Py, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 8.24 (s, 2H), 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0109] 1 H NMR results showed that the hetero[4]arene-based cocrystal material adsorbed toluene in a stoichiometric ratio of 1:1:1, but did not adsorb pyridine.

[0110] The PXRD test results are as follows Figure 1As shown, compared with the PXRD spectrum of the initially activated hetero[4]arene-based eutectic material, the PXRD spectrum of the hetero[4]arene-based eutectic material after being placed in toluene vapor for a period of time changes, which indicates that its unit cell parameters have changed, meaning that toluene has been adsorbed into the hetero[4]arene-based eutectic material; the spectrum of the hetero[4]arene-based eutectic material after being placed in pyridine vapor for a period of time changes very little, indicating that its unit cell parameters have almost not changed, meaning that the hetero[4]arene-based eutectic material has no adsorption capacity for pyridine.

[0111] Example 8

[0112] Adsorption of a 1:1 mixture of toluene and pyridine by the hetero[4]arene-based eutectic material: Take a 20mL culture bottle, add 0.5mL toluene and 0.5mL pyridine, named 1-TCNB@Bz / Cy, take 200mg of the hetero[4]arene-based eutectic material prepared in Example 1 and place it in a 5mL open culture bottle, place the open 5mL culture bottle in the above 20mL culture bottle, seal the 20mL culture bottle, and place it in a 25℃ water bath for 40h. Place the obtained powder in a 50℃ vacuum oven for 30 minutes.

[0113] The product characterization data prepared in this example are as follows:

[0114] 1-TCNB@Tol / Py, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 8.24 (s, 2H), 7.25 (t, J = 15Hz, 2H), 7.35 (s, 6H), 7 .24(d,J=10Hz,4H),7.17(d,J=10Hz,2H),7.15(t,J=15Hz,1H)6.85(d,J=10Hz,4H), 6.63(s,2H),5.71(s,2H),4.51(s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H ),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),2.34(s,3H),1.24(t,J=15Hz,12H).

[0115] exist 1 Only the signal of hydrogen atoms corresponding to toluene was found in the H NMR spectrum, which indicates that the cocrystal material based on hetero[4]arene can selectively adsorb toluene.

[0116] The PXRD test results are as follows Figure 1As shown, compared with the PXRD spectrum of the initially activated hetero[4]arene-based eutectic material, the PXRD spectrum of the hetero[4]arene-based eutectic material after being placed in the mixed vapor of toluene and pyridine for a period of time changes, and the spectrum change is the same as that of 1-TCNB@Tol, which indicates that the hetero[4]arene-based eutectic material can selectively adsorb toluene.

[0117] The results of headspace gas chromatography are as follows Figure 2 As shown, the results indicate that the hetero[4]arene-based cocrystal material can selectively adsorb toluene with a selectivity of 100%.

[0118] Example 9

[0119] Regeneration of hetero[4]arene-based eutectic material: 200 mg of hetero[4]arene-based eutectic material saturated with toluene was heated in a vacuum oven at 120°C for 9 h. The sample was designated as 1-TCNB-D.

[0120] The product characterization data prepared in this example are as follows:

[0121] 1-TCNB-D, 1 H NMR (500MHz, CD2Cl2, 293K) (ppm): 8.24 (s, 2H), 7.24 (d, J = 10Hz, 4H), 6.85 (d, J = 10Hz, 4H), 6.63 (s, 2H), 5.71 (s, 2H), 4.51 (s,2H),4.47(s,2H),3.99(s,12H),3.95–3.93(m,4H),3.91–3.88(m,4H),3.70(s,2H),3.66(s,2H),1.24(t,J=15Hz,12H).

[0122] exist 1 In the H NMR spectrum, it was found that the signal of the hydrogen atom corresponding to toluene had disappeared, which indicated that the cocrystal material based on hetero[4]arene had completed desorption and regeneration, and all benzene molecules had been released.

[0123] The PXRD test results are as follows Figure 1 As shown, compared with the PXRD spectrum of the initially activated hetero[4]arene-based eutectic material, the PXRD spectrum of the hetero[4]arene-based eutectic material after complete desorption changes very little, which indicates that the hetero[4]arene-based eutectic material has completed the desorption process and can be used for the next adsorption separation of toluene and pyridine.

[0124] Example 10

[0125] Recycling of hetero[4]arene-based eutectic material: Repeat Examples 3 and 4 with 200 mg of the regenerated hetero[4]arene-based eutectic material.

[0126] The results of headspace gas chromatography are as follows Figure 3 As shown, it is demonstrated that the cocrystal material based on hetero[4]arene can selectively adsorb benzene with a selectivity of up to 100%, and its selectivity does not decrease after being reused 5 times.

Claims

1. A eutectic material based on hetero[4]arene, characterized in that: A hetero[4]arene is used as an electron donor and 1,2,4,5-tetracyanobenzene is used as an electron acceptor. The electron donor and the electron acceptor are combined in a molar ratio of 1:1 to form a eutectic material based on hetero[4]arene, wherein: The hetero[4]arene has the following structure: The eutectic material is a monoclinic C crystal system, the space group is Fdd2, and the unit cell parameters of the eutectic material are: a=26.7226(9), b=35.7156(12), c=11.5081(4), α=90, β=90, γ=90.

2. The hetero[4]arene-based eutectic material according to claim 1, characterized in that: The hetero[4]arene is prepared by the following method: Step 1: Under nitrogen protection, ethyl bromide and 2,6-dihydroxynaphthalene in a molar ratio of 10:1 are placed in a saturated sodium hydroxide methanol solution, and stirred at 60-65° C. for reaction; after the reaction is completed, the mixture is cooled to room temperature, filtered, washed, and dried to obtain an intermediate product; Step 2: The intermediate product, 1,3-dimethoxybenzene and polyformaldehyde in a molar ratio of 1:1:2 are dissolved in chloroform, trifluoroacetic acid is added to catalyze the reaction during stirring at room temperature, and then heated to 60°C with stirring. After the reaction is complete and cooled to room temperature, a saturated sodium bicarbonate solution is added to quench the reaction. After separation, the hetero[4]arene is obtained by column chromatography.

3. A method for preparing a eutectic material based on hetero[4]arene according to claim 1, characterized in that: Hetero[4]arene and tetracyanobenzene were placed in n-hexane at a molar ratio of 1:1, heated to boiling, and n-hexane was added dropwise until all dissolved. The solution was stored at 0°C overnight, and the precipitated crystals were collected by filtration. The obtained crystals were vacuum dried at 50°C, and activated at 120°C for 9 hours to obtain an orange powder eutectic material of hetero[4]arene.

4. Use of the hetero[4]arene-based eutectic material according to claim 1 or 2 as a benzene or toluene adsorbent.

5. A method for separating benzene and cyclohexane, characterized in that: Placing the hetero[4]arene-based eutectic material according to claim 1 or 2 in a mixed vapor atmosphere of cyclohexane and benzene at a temperature less than 80° C., so that all the benzene is adsorbed by the eutectic material; At a temperature of less than 80° C., vacuum heating or reduced pressure heating is used to remove the mixture of benzene and cyclohexane adsorbed on the surface of the hetero[4]arene-based eutectic material, thereby achieving regeneration of the hetero[4]arene-based eutectic material; Alternatively, at 80 to 100° C., heating desorption is used to remove the benzene adsorbed and complexed by the hetero[4]arene-based eutectic material, while achieving regeneration of the hetero[4]arene-based eutectic material.

6. A method for separating toluene and pyridine, characterized in that: Placing the hetero[4]arene-based eutectic material according to claim 1 or 2 in a mixed vapor atmosphere of pyridine and toluene at a temperature less than 80° C., so that all the toluene is adsorbed by the eutectic material; At a temperature of less than 80° C., vacuum heating or reduced pressure heating is used to remove the toluene and pyridine mixture adsorbed on the surface of the hetero[4]arene-based eutectic material, thereby achieving regeneration of the hetero[4]arene-based eutectic material; Alternatively, at 80 to 100° C., heating desorption is used to remove toluene adsorbed and complexed by the hetero[4]arene-based eutectic material, while achieving regeneration of the hetero[4]arene-based eutectic material.

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