Separation method of furan and tetrahydrofuran

Abstract

The invention discloses a method for separating furan and tetrahydrofuran, and belongs to the field of adsorption materials. According to the invention, furan and tetrahydrofuran are selectively adsorbed and separated by using a eutectic material formed by using hetero [4] arene as an electron donor and 1, 2, 4, 5-tetracyanobenzene as an electron acceptor according to a molar ratio of 1: 1, the operation in the adsorption separation process is simple, and the requirement on equipment is relatively low; in the whole separation process, rectification operation is not needed, energy consumption is low, energy is saved, the production cost of tetrahydrofuran is reduced, and the problems that in an existing furan and tetrahydrofuran separation technology, energy consumption is large, the process is tedious, and a high-purity adsorbent needs to be used are solved.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials, and more specifically, to a method for separating furan and tetrahydrofuran. Background Technology

[0002] Furan and tetrahydrofuran are two extremely important organic chemicals and solvents. Furan is an aromatic unsaturated heterocyclic compound, and tetrahydrofuran is often prepared in industrial production through its catalytic hydrogenation. If the hydrogenation reaction is incomplete, the resulting tetrahydrofuran may contain unreacted furan precursors. These trace amounts of furan can affect the performance of tetrahydrofuran as a high-end solvent, and may even lead to the failure of subsequent reactions (such as polymerization and Grignard reactions). Conversely, if the furan used as a building block in synthesis contains tetrahydrofuran, it will dilute its effective concentration, thereby reducing the efficiency of subsequent synthetic reactions. In addition, tetrahydrofuran can generate explosive peroxides, which may increase the safety risks during its purification and storage. Therefore, developing an efficient separation technology for furan and tetrahydrofuran is of great significance for improving product value, achieving resource recycling, and ensuring production safety.

[0003] Patent CN119874644A discloses a method for purifying tetrahydrofuran. This method utilizes catalytic hydrogenation to hydrogenate dihydrofuran, an impurity in tetrahydrofuran, to tetrahydrofuran. Impurities n-butyraldehyde and isobutyraldehyde are hydrogenated to form alcohols that are easily separated from tetrahydrofuran. The purified tetrahydrofuran contains dihydrofuran at a concentration below 3 ppm, overcoming the cumbersome process of existing tetrahydrofuran refining techniques. However, this method suffers from problems such as complex equipment, high energy consumption, and high cost.

[0004] Patent CN119930548A discloses a method for separating a mixture of tetrahydrofuran / methanol / water by reactive distillation. Water is separated by reactive distillation, tetrahydrofuran by atmospheric or low-pressure extractive distillation, and methanol by extractive distillation. Partial thermal integration is achieved between the water reactive or methanol extractive distillation column and the tetrahydrofuran extractive distillation low-pressure column through heat exchange. In the water reactive distillation column, water and ethylene oxide react to produce ethylene glycol with a molar purity exceeding 99.9%, while the molar purity of tetrahydrofuran and methanol reaches over 99.5%. However, the entire process is complex, and both distillation and extraction involve significant energy consumption, resulting in high operating costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a method for separating furan and tetrahydrofuran. The method uses hetero[4] aromatic hydrocarbons as electron donors and 1,2,4,5-tetracyanobenzene as electron acceptors. The two are separated by a eutectic material formed in a molar ratio of 1:1 to selectively adsorb and separate furan and tetrahydrofuran, thus solving the problems of high energy consumption, complicated process and need for high-purity adsorbent in the existing furan and tetrahydrofuran separation technology.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for separating furan and tetrahydrofuran includes: placing a hetero[4]aromatic eutectic material in a mixture of furan and tetrahydrofuran at a temperature <80°C to selectively adsorb furan and achieve separation of furan and tetrahydrofuran; The eutectic material based on hetero[4]aromatics uses hetero[4]aromatics as an electron donor and 1,2,4,5 Tetracyanobenzene is an electron acceptor, and the eutectic material is formed by combining electron donors and electron acceptors in a molar ratio of 1:1. The hetero[4]aromatic hydrocarbon has the following structure: .

[0008] This invention also discloses the application of a hetero[4]aromatic eutectic material in the adsorption and separation of a mixture of furan and tetrahydrofuran, wherein the hetero[4]aromatic eutectic material uses hetero[4]aromatics as an electron donor and 1,2,4,5 Tetracyanobenzene is an electron acceptor, and the eutectic material formed by combining the electron donor and the electron acceptor in a molar ratio of 1:1; the application includes: placing the eutectic material based on hetero[4] aromatics in a mixture of furan and tetrahydrofuran at a temperature <80°C to selectively adsorb furan, thereby achieving the separation of furan and tetrahydrofuran; the hetero[4] aromatics have the following structure: .

[0009] Implementing the embodiments of the present invention will have the following beneficial effects: Compared with the prior art, the preparation process of the eutectic material based on hetero[4]aromatic hydrocarbons provided by the present invention is simple and efficient, the eutectic produced has good stability, and has a good adsorption and separation effect on the mixture of furan and tetrahydrofuran. The separation process has obvious color change. After adsorbing furan, the color of the eutectic changes from orange to black. The operation is simple and the equipment requirements are low. The separation process does not require distillation, the energy consumption is low, energy is saved, and the production cost of furan is reduced. The crystal material used has high stability and can be recycled. The separation effect will not be reduced. Attached Figure Description

[0010] Figure 1 The image shows the powder X-ray diffraction (PXRD) pattern of the eutectic material based on hetero[4] aromatics after adsorption of furan and tetrahydrofuran.

[0011] Figure 2 The selective adsorption effect of the eutectic material based on hetero[4] aromatic hydrocarbons on the mixture of furan and tetrahydrofuran.

[0012] Figure 3 The recycling capacity of eutectic materials based on hetero[4] aromatic hydrocarbons. Detailed Implementation

[0013] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0014] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0015] In order to solve the defects of high energy consumption, complicated process and need for high purity desorbent in the separation technology of furan and tetrahydrofuran, this invention discloses a method for separating furan and tetrahydrofuran, including: placing a eutectic material based on hetero[4]aromatics in a mixture of furan and tetrahydrofuran under the condition of temperature <80°C to selectively adsorb furan and achieve the separation of furan and tetrahydrofuran.

[0016] Specifically, during the adsorption process, the crystalline structure of the eutectic material based on hetero[4]arene will change. Due to the multiple non-covalent interactions between CH-π, CH-O, and CH-N, the furan in the mixture will form a host-guest complex with the eutectic material based on hetero[4]arene, and the stoichiometric ratio of the eutectic polymer is 1:1.

[0017] Furthermore, the eutectic material based on hetero[4]aromatics uses hetero[4]aromatics as electron donors and 1,2,4,5 Tetracyanobenzene is an electron acceptor, and the eutectic material is formed by combining the electron donor and electron acceptor in a molar ratio of 1:1; wherein, hetero[4]aromatic hydrocarbons have the following structure: .

[0018] In one specific embodiment, the preparation method of the eutectic material based on hetero[4]aromatics includes: placing hetero[4]aromatics and 1,2,4,5-tetracyanobenzene in n-hexane at a molar ratio of 1:1, heating to boiling, adding n-hexane dropwise until completely dissolved, storing the solution at 0°C overnight, filtering and collecting the precipitated crystals, drying the obtained crystals under vacuum at 50°C, and activating at 120°C for 9 hours to obtain an orange powder eutectic material. The activated eutectic material can be directly used for the adsorption and separation of a mixture of tetrahydrofuran and furan.

[0019] In one specific embodiment, the eutectic material is a monoclinic C crystal system with space group Fdd2, and the 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.

[0020] In one specific embodiment, the temperature for selective adsorption of furan is 25~35°C.

[0021] In one specific embodiment, the selective adsorption time of furan can be varied by factors such as the amount of sample and the proportion of furan in the mixture.

[0022] In one specific embodiment, the furan and tetrahydrofuran mixture is a mixture of furan and tetrahydrofuran vapors.

[0023] In one specific embodiment, the volume ratio of furan to tetrahydrofuran in the furan and tetrahydrofuran mixture is 1:1.

[0024] In one specific embodiment, the method further includes: after selective adsorption of furan is completed, removing the furan and tetrahydrofuran mixture from the surface of the eutectic material by vacuum heating or reduced pressure heating; the temperature of vacuum heating or reduced pressure heating is <80°C.

[0025] In one specific embodiment, the vacuum heating or reduced-pressure heating time can be adjusted according to the sample volume. At temperatures below 80°C, the host-guest complex remains stable, while the furan and tetrahydrofuran mixture adsorbed on the surface of the eutectic material can be gradually removed. By removing the surface-adsorbed mixture, the purity of the adsorbed and separated furan can be further improved.

[0026] In one specific embodiment, the method further includes: desorbing the adsorbed furan complexed by the eutectic material by vacuum heating to regenerate the eutectic material; the vacuum heating temperature is 100~120℃, at which temperature the eutectic polymer is unstable and the adsorbed furan molecules will be gradually released, while the eutectic material based on hetero[4]aromatics is stable and only the crystal form changes during the desorption process. After desorption, the regenerated eutectic material based on hetero[4]aromatics is obtained, which can be used to adsorb and separate tetrahydrofuran and furan for the next cycle.

[0027] In one specific embodiment, the heating desorption time can be adjusted according to the sample amount.

[0028] This invention also discloses the application of a hetero[4]aromatic eutectic material in the adsorption and separation of a mixture of furan and tetrahydrofuran. The hetero[4]aromatic eutectic material uses hetero[4]aromatics as an electron donor and 1,2,4,5 Tetracyanobenzene is an electron acceptor, and the eutectic material formed by combining the electron donor and the electron acceptor in a molar ratio of 1:1; the application includes: placing the eutectic material based on hetero[4] aromatics in a mixture of furan and tetrahydrofuran under the condition of temperature <80°C to selectively adsorb furan and achieve the separation of furan and tetrahydrofuran; [4]Aromatic hydrocarbons, having the following structure: .

[0029] The following are specific embodiments. Example 1 Preparation of eutectic material based on hetero[4] aromatic hydrocarbons: Weigh 2 g of hetero[4] aromatic hydrocarbons (prepared according to paragraphs 0061-0065 of the specification with publication number CN116606196A) and 0.5 g of 1,2,4,5-tetracyanobenzene and place them in 20 mL of n-hexane. Heat to boiling and add n-hexane dropwise until completely dissolved. Store the solution at 0 °C overnight, filter and collect the precipitated crystals, dry the obtained crystals under vacuum at 50 °C, and activate at 120 °C for 9 h to obtain an orange powder, denoted as H4-TCNB.

[0030] The characterization data of the product prepared in this embodiment are as follows: H4-TCNB, 1 H NMR (400 MHz, CDCl3, 293 K) (ppm): 7.27 (d, J = 10 Hz, 4H), 6.83 (d, J = 10 Hz, 4H), 6.61 (s, 2H), 5.80 (s, 2H), 4.58 (s, 2H), 4.54 (s,2H), 3.99 (s, 12H), 3.95 – 3.93 (m, 4H), 3.91 – 3.88 (m, 4H), 3.74 (s, 2H),3.70 (s, 2H), 1.24 (t, J = 15 Hz, 12H). PXRD test results are as follows Figure 1 As shown, the obtained eutectic material based on hetero[4] aromatic hydrocarbons has good crystallinity.

[0031] Example 2 Adsorption of furan or tetrahydrofuran by eutectic material based on hetero[4] aromatics: Take two 20 mL culture bottles, add 1 mL of furan and 1 mL of tetrahydrofuran respectively, and name them H4-TCNB@Furan and H4-TCNB@THF. Take 200 mg of the eutectic material based on hetero[4] aromatics prepared in Example 1 and place it in two 5 mL open culture bottles. Place the two open 5 mL culture bottles in two 20 mL culture bottles respectively. Seal the 20 mL culture bottles and place them in a 25 ℃ water bath for 30 h.

[0032] The characterization data of the product prepared in this embodiment are as follows: H4-TCNB@Furan, 1 H NMR (400 MHz, CDCl3, 293 K) (ppm): 7.45 (t, 2 H),7.29 (d, J = 10 Hz, 4H), 6.81 (d, J = 10 Hz, 4H), 6.61 (s, 2H), 6.40 (t, 2 H),5.80 (s, 2H), 4.58 (s, 2H), 4.54 (s, 2H), 3.99 (s, 12H), 3.92 – 3.89 (m, 4H),3.85 – 3.82 (m, 4H), 3.74 (s, 2H), 3.70 (s, 2H), 1.23 (t, J = 15 Hz, 12H). H4-TCNB@THF, 1 H NMR (400 MHz, CDCl3, 293 K) (ppm): 7.29 (d, J = 10 Hz, 4H), 6.83 (d, J = 10 Hz, 4H), 6.61 (s, 2H), 5.80 (s, 2H), 4.58 (s, 2H), 4.54(s, 2H), 3.99 (s, 12H), 3.93 – 3.89 (m, 4H), 3.85 – 3.81 (m, 4H), 3.74 (s,2H), 3.70 (s, 2H), 1.24 (t, J = 15 Hz, 12H). 1 H NMR results showed that the eutectic material based on hetero[4] aromatics adsorbed furan in a stoichiometric ratio of 1:1, but did not adsorb tetrahydrofuran.

[0033] PXRD test results are as follows Figure 1 As shown, compared with the PXRD spectrum of the initially activated hetero[4]aromatic eutectic material, the PXRD spectrum of the hetero[4]aromatic eutectic material after being placed in furan vapor for a period of time changed, indicating that its unit cell parameters had changed, meaning that furan had been adsorbed into the hetero[4]aromatic eutectic material; the spectrum of the hetero[4]aromatic eutectic material after being placed in tetrahydrofuran vapor for a period of time changed very little, indicating that its unit cell parameters hardly changed, meaning that the hetero[4]aromatic eutectic material has no adsorption capacity for tetrahydrofuran.

[0034] Example 3 Adsorption of mixed vapors of furan and tetrahydrofuran (v:v=1:1) by eutectic material based on hetero[4] aromatics: Take a 20 mL culture bottle, add 0.5 mL of furan and 0.5 mL of tetrahydrofuran, named H-TCNB@Furan / THF, take 200 mg of the eutectic material based on hetero[4] aromatics prepared in Example 1 and place it in a 5 mL open culture bottle, place the open 5 mL culture bottle in the above 20 mL culture bottle, seal the 20 mL culture bottle, place it in a 25 ℃ water bath for 40 h, and place the obtained powder in a 45 ℃ vacuum oven for 30 min.

[0035] The characterization data of the product prepared in this embodiment are as follows: H-TCNB@Furan / THF, 1 H NMR (400 MHz, CDCl3, 293 K) (ppm): 7.46 (t, 2 H),7.29 (d, J = 10 Hz, 4H), 6.83 (d, J = 10 Hz, 4H), 6.61 (s, 2H), 6.40 (t, 2 H),5.80 (s, 2H), 4.58 (s, 2H), 4.54 (s, 2H), 3.99 (s, 12H), 3.92 – 3.88 (m, 4H),3.85 – 3.82 (m, 4H), 3.74 (s, 2H), 3.70 (s, 2H), 1.23 (t, J = 15 Hz, 12H). exist 1 The H NMR spectrum only showed the signal of hydrogen atoms corresponding to furan, which indicates that the eutectic material based on hetero[4] aromatic hydrocarbons can selectively adsorb furan.

[0036] PXRD test results are as follows Figure 1As shown, compared with the PXRD spectrum of the initially activated hetero[4]aromatic cocrystal material, the PXRD spectrum of the hetero[4]aromatic cocrystal material placed in a mixed vapor of furan and tetrahydrofuran for a period of time changed, and the spectrum change was the same as that of H-TCNB@Furan. This indicates that the hetero[4]aromatic cocrystal material can selectively adsorb furan. The headspace gas chromatography results are as follows: Figure 2 As shown, the results indicate that the eutectic material based on hetero[4] aromatics can selectively adsorb furan with a selectivity of 96.3%.

[0037] Example 4 Regeneration based on hetero[4]aromatic eutectic material: 200 mg of eutectic material based on hetero[4]aromatic eutectic material with saturated adsorption of furan was heated in a vacuum oven at 120℃ for 9 h, and the sample was recorded as H4-TCNB-D.

[0038] The characterization data of the product prepared in this embodiment are as follows: H4-TCNB-D, 1 H NMR (400 MHz, CDCl3, 293 K) (ppm): 7.27 (d, J = 10 Hz, 4H), 6.83 (d, J = 10 Hz, 4H), 6.61 (s, 2H), 5.80 (s, 2H), 4.58 (s, 2H), 4.54 (s,2H), 3.99 (s, 12H), 3.95 – 3.93 (m, 4H), 3.91 – 3.89 (m, 4H), 3.74 (s, 2H), 3.70 (s, 2H), 1.23 (t, J = 15 Hz, 12H). exist 1 The H NMR spectrum showed that the signal of the hydrogen atom corresponding to furan had disappeared, which indicates that the eutectic material based on hetero[4] aromatic hydrocarbons has completed desorption and regeneration, and all furan molecules have been released.

[0039] Example 5 Reuse of eutectic materials based on hetero[4] aromatics: 200 mg of the regenerated eutectic material based on hetero[4] aromatics was reused in Examples 3 and 4.

[0040] The results of reuse are as follows Figure 3 As shown, this eutectic material can selectively adsorb furan, and its selectivity does not decrease after being used five times.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for separating furan and tetrahydrofuran, characterized in that, include: Under the condition of temperature <80°C, the eutectic material based on hetero[4] aromatic hydrocarbons was placed in a mixture of furan and tetrahydrofuran to selectively adsorb furan and achieve the separation of furan and tetrahydrofuran; The eutectic material based on hetero[4]aromatics uses hetero[4]aromatics as an electron donor and 1,2,4,5 Tetracyanobenzene is an electron acceptor, and the eutectic material is formed by combining electron donors and electron acceptors in a molar ratio of 1:

1. The hetero[4]aromatic hydrocarbon has the following structure: 。 2. The method for separating furan and tetrahydrofuran according to claim 1, characterized in that, The preparation method of the eutectic material based on hetero[4]aromatics includes: The hetero[4] aromatic hydrocarbon and 1,2,4,5-tetracyanobenzene were placed in n-hexane at a molar ratio of 1:1, heated to boiling, and n-hexane was added dropwise until completely dissolved. The solution was stored at 0°C overnight, and the precipitated crystals were collected by filtration. The obtained crystals were dried under vacuum at 50°C and activated at 120°C for 9 hours to obtain the eutectic material based on hetero[4] aromatic hydrocarbon.

3. The method for separating furan and tetrahydrofuran according to claim 1, characterized in that, The temperature for selectively adsorbing furan is 25~35℃.

4. The method for separating furan and tetrahydrofuran according to claim 1, characterized in that, The furan and tetrahydrofuran mixture is a mixture of furan and tetrahydrofuran vapors.

5. The method for separating furan and tetrahydrofuran according to claim 1, characterized in that, The volume ratio of furan to tetrahydrofuran in the furan and tetrahydrofuran mixture is 1:

1.

6. The method for separating furan and tetrahydrofuran according to claim 1, characterized in that, The method further includes: after selective adsorption of furan is completed, removing the furan and tetrahydrofuran mixture from the surface of the eutectic material by vacuum heating or reduced pressure heating; the temperature of the vacuum heating or reduced pressure heating is <80°C.

7. The method for separating furan and tetrahydrofuran according to claim 1, characterized in that, The method further includes: using vacuum heating to desorb the furan adsorbed and complexed by the eutectic material to regenerate the eutectic material; the temperature of the vacuum heating is 100~120℃.

8. An application of a hetero[4]aromatic eutectic material in the adsorption and separation of a mixture of furan and tetrahydrofuran, characterized in that, The eutectic material based on hetero[4]aromatics uses hetero[4]aromatics as an electron donor and 1,2,4,5 Tetracyanobenzene is an electron acceptor, and the eutectic material is formed by combining electron donors and electron acceptors in a molar ratio of 1:

1. The application includes: placing a hetero[4]aromatic eutectic material in a mixture of furan and tetrahydrofuran at a temperature <80°C to selectively adsorb furan and achieve separation of furan and tetrahydrofuran; The hetero[4]aromatic hydrocarbon has the following structure: 。

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