Application of hetero[3]arene crystal material in adsorptive separation of 3-methylthiophene and n-heptane mixture

Abstract

The application discloses application of a hetero[3]arene crystal material in adsorption separation of a 3-methyl thiophene and n-heptane mixture, and utilizes the non-porous self-adapting crystal material of the hetero[3]arene to adsorb and separate the 3-methyl thiophene and n-heptane mixture, so that energy consumption is low, a process is simple, and defects such as high energy consumption, a complicated process, the need to use high-purity desorption agents and high cost existing in a 3-methyl thiophene and n-heptane separation technology are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of adsorption technology, and more particularly, to application of a hetero[3]arene crystal material in adsorption separation of a 3-methylthiophene and n-heptane mixture. BACKGROUND

[0002] 3-methylthiophene and n-heptane exist in gasoline. Among them, with the development of social economy, sulfur oxides produced by combustion of 3-methylthiophene as a thiophene sulfide have caused great threat to the environment and human health, so removing the pollutant 3-methylthiophene has become an important research topic. In addition, n-heptane has the advantages of low energy ignition point and high combustion efficiency, and is used as fuel and solvent to improve the combustion efficiency of gasoline. In this study, 3-methylthiophene and n-heptane are used to simulate gasoline. At present, the common technology for removing 3-methylthiophene from gasoline is mainly extraction desulfurization, which consumes a lot of energy and is not conducive to the sustainable development of energy. In the past few decades, adsorption method has developed very rapidly, and a variety of porous adsorbents have been explored, such as zeolites, porous organic polymers, covalent organic frameworks, metal-organic frameworks, etc. Although their high specific surface area and rigid structure are conducive to the adsorption of guests, factors such as poor thermal stability, high energy consumption and complex design limit their application. Therefore, there is an urgent need to develop a new type of material with simple synthesis process, high stability and reusability to effectively separate 3-methylthiophene and n-heptane.

[0003] At present, the separation of thiophene substances from gasoline mainly relies on extraction desulfurization, membrane permeation desulfurization, etc. A marine fuel desulfurization extractant and its extraction desulfurization method are disclosed in Chinese Patent No. CN113684052A. The extractant is an ionic liquid extractant, which includes n-hexanol modified chlorohexadecyl pyridine and organic acid. However, this method has a complex device and high energy consumption. Chinese Patent No. CN118341272A discloses a PEG-ncp particle filled hybrid membrane loaded with Ag + , a preparation method and a pervaporation gasoline desulfurization method thereof, which uses a thiophene and n-octane mixed solution as simulated gasoline. The hybrid membrane for pervaporation desulfurization includes a support layer and a separation layer coated on the support layer. However, this method has problems such as complex preparation, poor film forming property, brittle quality, and high production cost. Chinese Patent No. CN112473573A discloses a preparation method of Pd(II)-DA-SiO2 composite aerogel and its application. This method uses tetraethyl orthosilicate as raw material, and introduces hydrochloric acid dopamine and Pb 2+ for modification. However, this method has problems such as complex preparation and high price. SUMMARY

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide an application of a hetero[3]aromatic hydrocarbon crystal material in the adsorption separation of a mixture of 3-methylthiophene and n-heptane. The hetero[3]aromatic hydrocarbon crystal material is used to adsorb and separate the mixture of 3-methylthiophene and n-heptane, with low energy consumption and a simple process, thereby avoiding the defects of the 3-methylthiophene and n-heptane separation technology, such as high energy consumption, complicated process, the need for a high-purity desorbent, and high cost.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] Application of hetero[3]arene crystal material in the adsorption separation of 3-methylthiophene and n-heptane mixture, wherein the chemical structure of the hetero[3]arene crystal material is as follows:

[0007]

[0008] The present invention also discloses a method for separating 3-methylthiophene and n-heptane, which utilizes hetero[3]arene crystal material to adsorb and separate the mixture of 3-methylthiophene and n-heptane. The chemical structure of the hetero[3]arene crystal material is as follows:

[0009]

[0010] Optionally, the specific steps of using hetero[3]arene crystal material to absorb and separate the mixture of 3-methylthiophene and n-heptane are as follows: placing the hetero[3]arene crystal material in a mixed vapor of 3-methylthiophene and n-heptane or a mixed solution of 3-methylthiophene and n-heptane for absorption and separation, and the temperature of the absorption and separation is less than 80°C.

[0011] Optionally, after the adsorption is completed, vacuum heating or reduced pressure heating is used to remove the mixture of 3-methylthiophene and n-heptane adsorbed on the surface of the hetero[3]arene crystal material, and the temperature of the vacuum heating or reduced pressure heating is less than 80°C.

[0012] Optionally, heating desorption is used to remove the 3-methylthiophene adsorbed and complexed by the hetero[3]arene crystalline material, thereby achieving regeneration of the hetero[3]arene crystalline material; the heating desorption temperature is 80 to 100°C.

[0013] Optionally, the preparation method of the hetero[3]arene crystalline material comprises the following steps: placing the hetero[3]arene in acetone, heating to boiling, adding acetone dropwise until all the acetone is dissolved, storing the solution at 0°C overnight, filtering and collecting the precipitated crystals, and vacuum drying and activating the obtained crystals once to obtain the hetero[3]arene crystalline material.

[0014] Optionally, the activation temperature is 150° C. and the activation time is 2 h.

[0015] Optionally, the vacuum drying temperature is 50°C.

[0016] The implementation of the present invention will have the following beneficial effects:

[0017] The present invention utilizes hetero[3]arene crystal materials to separate 3-methylthiophene from a mixture of gaseous or liquid 3-methylthiophene and n-heptane with a purity of 100%, and the separation process is simple to operate and requires low equipment. The separation process does not require distillation operation, has low energy consumption, saves energy, and reduces the production cost of 3-methylthiophene. The crystal material used is highly stable and can be recycled without reducing the separation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The PXRD data of the hetero[3]arene crystalline material of the present invention after adsorption of 3-methylthiophene and n-heptane vapor.

[0019] Figure 2 This is the TG data of the hetero[3]arene crystalline material of the present invention after adsorption of 3-methylthiophene vapor.

[0020] Figure 3 This is the TG data of the hetero[3]arene crystalline material of the present invention after adsorption of n-heptane vapor.

[0021] Figure 4 This is a headspace gas chromatogram of the hetero[3]arene crystalline material of the present invention after adsorption of 3-methylthiophene and n-heptane mixed vapor.

[0022] Figure 5 This is a cyclic performance diagram of the hetero[3]arene crystal material of the present invention for adsorption of mixed vapor of 3-methylthiophene and n-heptane.

[0023] Figure 6 This is the TG data of the hetero[3]arene crystal material of the present invention after adsorption of 3-methylthiophene solution.

[0024] Figure 7 This is the TG data of the hetero[3]arene crystalline material of the present invention after adsorption on n-heptane solution.

[0025] Figure 8 The PXRD data of the hetero[3]arene crystalline material of the present invention after adsorption of 3-methylthiophene and n-heptane solution.

[0026] Figure 9 This is a headspace gas chromatogram of the hetero[3]arene crystalline material of the present invention after adsorption of a mixed solution of 3-methylthiophene and n-heptane. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0028] The present invention discloses an application of a hetero[3]arene crystal material in the adsorption separation of a mixture of 3-methylthiophene and n-heptane. The chemical structure of the hetero[3]arene crystal material is as follows:

[0029]

[0030] Specifically, due to the differences in the molecular structures of 3-methylthiophene and n-heptane, hetero[3]arene crystals can form a host-guest complex with 3-methylthiophene in a stoichiometric ratio of 1:1. This host-guest complex gradually decomplexes upon heating, releasing the adsorbed 3-methylthiophene. After the desorption process is complete, the material can be reused without loss of selectivity.

[0031] The present invention also discloses a method for separating 3-methylthiophene and n-heptane, which utilizes hetero[3]arene crystal material to adsorb and separate the mixture of 3-methylthiophene and n-heptane. The chemical structure of the hetero[3]arene crystal material is as follows:

[0032]

[0033] In a specific embodiment, the specific steps of using hetero[3]arene crystal material to separate 3-methylthiophene and n-heptane mixture by adsorption are as follows: placing the hetero[3]arene crystal material in a mixed vapor of 3-methylthiophene and n-heptane or a mixed solution of 3-methylthiophene and n-heptane for adsorption separation, and the adsorption separation temperature is less than 80°C.

[0034] In a specific embodiment, the adsorption time can be changed according to factors such as the amount of sample and the ratio of 3-methylthiophene in the mixture.

[0035] Specifically, during the adsorption process, the hetero[3]arene crystalline material undergoes a change in crystalline form. Due to multiple non-covalent interactions, 3-methylthiophene in the mixture forms a host-guest complex with the hetero[3]arene, with a stoichiometric ratio of 1:1.

[0036] In a specific embodiment, after the adsorption is completed, vacuum heating or reduced pressure heating is used to remove the 3-methylthiophene and n-heptane mixture adsorbed on the surface of the hetero[3]arene crystal material, and the temperature of the vacuum heating or reduced pressure heating is less than 80°C.

[0037] In one embodiment, the heating time can be adjusted according to the sample amount.

[0038] Specifically, at temperatures below 80°C, the formed host-guest complex remains stable, while the adsorbed 3-methylthiophene and n-heptane mixture can be gradually removed. By removing the adsorbed mixed vapor, the purity of the adsorbed 3-methylthiophene can be further improved.

[0039] In a specific embodiment, heating desorption is used to remove 3-methylthiophene adsorbed and complexed by the hetero[3]arene crystalline material, thereby achieving regeneration of the hetero[3]arene crystalline material; the heating desorption temperature is 80°C to 100°C.

[0040] Specifically, at a heating desorption temperature of 80°C to 100°C, the host-guest complex is unstable, and the adsorbed 3-methylthiophene molecules are gradually released. However, the hetero[3]arene crystalline material is stable, and only undergoes a change in crystalline form during the desorption process. After desorption, the regenerated hetero[3]arene crystalline material is obtained, which can be used to adsorb and separate the 3-methylthiophene and n-heptane mixture for the next cycle.

[0041] In one embodiment, the heating desorption time can be adjusted according to the sample amount.

[0042] In a specific embodiment, the preparation method of hetero[3]arene crystalline material comprises the following steps: placing hetero[3]arene in acetone, heating to boiling, adding acetone dropwise until all the acetone is dissolved, storing the solution at 0°C overnight, filtering and collecting the precipitated crystals, and vacuum drying and activating the obtained crystals to obtain hetero[3]arene crystalline material.

[0043] In one embodiment, the activation temperature is 150° C. and the activation time is 2 hours.

[0044] In one embodiment, the vacuum drying temperature is 50°C.

[0045] The following are specific embodiments

[0046] Example 1

[0047] Preparation of hetero[3]arene crystalline material: Weigh 2 g of hetero[3]arene and place it in 20 mL of acetone. Heat to boiling, add acetone dropwise until it is completely dissolved, store the solution at 0°C overnight, filter and collect the precipitated crystals, dry the obtained crystals in a vacuum at 50°C, and activate at 150°C for 2 h to obtain a white powder, which is recorded as 1.

[0048] The product characterization data prepared in this example are as follows:

[0049] 1, 1H NMR (600MHz, CDCl3, 293K, ppm) δ7.11(d,J=6Hz,2H),6.66(d,J=6Hz,2H),6.28(s,2H),6.22(s,2H), 4.11–3.97(m,8H),3.83(s,6H),3.64(s,6H),3.57(s,6H),3.40(d,J=18Hz,2H),1.39(t,J=6Hz,6H).

[0050] The PXRD test results are as follows Figure 1 As shown, the obtained hetero[3]arene crystalline material has good crystallinity.

[0051] Example 2

[0052] Adsorption of hetero[3]arene crystalline materials on individual 3-methylthiophene and n-heptane: Take three 20 mL inoculum bottles, add 1 mL of 3-methylthiophene and n-heptane respectively, and name them as a and b. Take 20 mg of the hetero[3]arene crystalline material prepared in Example 1 and place them in three 5 mL open inoculum bottles respectively. Place the three open 5 mL inoculum bottles in three 20 mL inoculum bottles respectively. Seal the 20 mL inoculum bottles and place them in a 25°C water bath for 24 hours.

[0053] The product characterization data prepared in this example are as follows:

[0054] TG test results are as follows Figure 2 、 3 As shown, the hetero[3]arene crystal material has a significant adsorption effect on 3-methylthiophene, but no adsorption on n-heptane.

[0055] The PXRD test results are as follows Figure 1 As shown, compared with the PXRD spectrum of the initially activated hetero[3]aromatic hydrocarbon crystal material, the PXRD spectrum of the hetero[3]aromatic hydrocarbon crystal material after being placed in 3-methylthiophene vapor for a period of time changes (1+a), which indicates that its unit cell parameters have changed, meaning that 3-methylthiophene has been adsorbed into the hetero[3]aromatic hydrocarbon crystal material; the spectrum of the hetero[3]aromatic hydrocarbon crystal material after being placed in n-heptane vapor for a period of time changes very little (1+b), indicating that its unit cell parameters have almost no change, meaning that the hetero[3]aromatic hydrocarbon crystal material has no adsorption capacity for n-heptane.

[0056] Example 3

[0057] Adsorption of a 1:1 (v:v) mixture of 3-methylthiophene and n-heptane in a 20 mL inoculum bottle was performed. 1 mL of 3-methylthiophene and 1 mL of n-heptane were added to a 20 mL inoculum bottle, which was named ab. 20 mg of the hetero[3]arene crystalline material obtained in Example 1 was placed in a 5 mL open inoculum bottle. The open 5 mL inoculum bottle was placed in the above 20 mL inoculum bottle, and the 20 mL inoculum bottle was sealed and placed in a 25°C water bath for 24 h. The resulting powder was placed in a 45°C vacuum oven for 30 min.

[0058] The product characterization data prepared in this example are as follows:

[0059] The PXRD test results are as follows Figure 1 As shown, compared with the PXRD spectrum of the initially activated hetero[3]arene crystal material, the PXRD spectrum of the hetero[3]arene crystal material after being placed in the mixed vapor of 3-methylthiophene and n-heptane for a period of time shows obvious changes (1+ab), and the spectrum changes are the same as a, which indicates that the hetero[3]arene crystal material can selectively adsorb 3-methylthiophene.

[0060] The results of headspace gas chromatography are as follows Figure 4 As shown, the results indicate that hetero[3]arene crystalline materials can selectively adsorb 3-methylthiophene with a selectivity of 100%.

[0061] Example 4

[0062] Reuse of hetero[3]arene crystal material: 20 mg of hetero[3]arene crystal material saturated with 3-methylthiophene was heated in a vacuum oven at 100°C for 2 h to obtain regenerated hetero[3]arene. The regenerated hetero[3]arene crystal material was used to repeat Example 4. Figure 5 It is shown that the selectivity does not decrease after being reused 5 times.

[0063] Example 5

[0064] Adsorption of hetero[3]arene crystalline materials on separate 3-methylthiophene and n-heptane solutions: Take three 5 mL inoculum bottles, add 1 mL of 3-methylthiophene and n-heptane respectively, and designate them as c and d. Take 20 mg of the hetero[3]arene crystalline material prepared in Example 1 and place it in three 5 mL open inoculum bottles respectively. Seal the 5 mL inoculum bottles and place them in a 25°C water bath for 60 min.

[0065] The product characterization data prepared in this example are as follows:

[0066] TG test results are as follows Figure 6 、 7 As shown, the hetero[3]arene crystal material has a significant adsorption effect on 3-methylthiophene, but no adsorption on n-heptane.

[0067] The PXRD test results are as follows Figure 8 As shown, compared with the PXRD spectrum of the initially activated hetero[3]arene crystal material, the PXRD spectrum of the hetero[3]arene crystal material after being placed in the 3-methylthiophene solution for a period of time shows obvious changes (1+c), which means that 3-methylthiophene has been adsorbed into the hetero[3]arene crystal material; the spectrum of the hetero[3]arene crystal material after being placed in the n-heptane solution for a period of time changes very little, indicating that its unit cell parameters have almost no change (1+d), which means that the hetero[3]arene crystal material has no adsorption capacity for n-heptane.

[0068] Example 6

[0069] Adsorption of a 1:1 (v:v) mixed solution of hetero[3]arene crystalline material 3-methylthiophene and n-heptane: Take a 5 mL inoculum bottle, add 1 mL 3-methylthiophene and 1 mL n-heptane, and name it cd. Take 20 mg of the hetero[3]arene crystalline material prepared in Example 1 and place it in the 5 mL open inoculum bottle. Seal the 5 mL inoculum bottle and place it in a 25°C water bath for 30 minutes. The resulting powder is placed in a 45°C vacuum oven for 60 minutes.

[0070] The product characterization data prepared in this example are as follows:

[0071] The PXRD test results are as follows Figure 8 As shown in FIG, compared with the PXRD spectrum of the initially activated hetero[3]arene crystal material, the PXRD spectrum of the hetero[3]arene crystal material after being placed in a mixed solution of 3-methylthiophene and n-heptane for a period of time changes (1+cd), and the spectrum change is the same as that in FIG. This indicates that the hetero[3]arene crystal material can selectively adsorb 3-methylthiophene.

[0072] The results of headspace gas chromatography are as follows Figure 9 As shown, the results indicate that hetero[3]arene crystalline materials can selectively adsorb 3-methylthiophene with a selectivity of 100%.

[0073] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. Application of hetero[3]arene crystal material in the adsorption separation of 3-methylthiophene and n-heptane mixture, characterized in that: The chemical structural formula of the hetero[3]arene crystalline material is as follows: 。 2. A method for separating 3-methylthiophene and n-heptane, characterized in that: A mixture of 3-methylthiophene and n-heptane is separated by adsorption using hetero[3]arene crystal materials, wherein the chemical structure of the hetero[3]arene crystal materials is as follows: ； The specific steps of using hetero[3]arene crystal material to absorb and separate a mixture of 3-methylthiophene and n-heptane are as follows: placing the hetero[3]arene crystal material in a mixed vapor of 3-methylthiophene and n-heptane or a mixed solution of 3-methylthiophene and n-heptane for absorption and separation, wherein the temperature of the absorption and separation is less than 80°C; After the adsorption is completed, vacuum heating or reduced pressure heating is used to remove the 3-methylthiophene and n-heptane mixture adsorbed on the surface of the hetero[3]arene crystal material, and the temperature of the vacuum heating or reduced pressure heating is less than 80 °C.

3. The method for separating 3-methylthiophene and n-heptane according to claim 2, wherein: The 3-methylthiophene adsorbed and complexed by the hetero[3]arene crystal material is removed by heating desorption, thereby achieving the regeneration of the hetero[3]arene crystal material; the heating desorption temperature is 80°C to 100°C.

4. The method for separating 3-methylthiophene and n-heptane according to claim 2, characterized in that: The preparation method of hetero[3]arene crystalline material comprises the following steps: The hetero[3]arene is placed in acetone, heated to boiling, and acetone is added dropwise until all dissolved. The solution is stored at 0°C overnight, and the precipitated crystals are collected by filtration. The obtained crystals are vacuum dried and activated once to obtain the hetero[3]arene crystalline material.

5. The method for separating 3-methylthiophene and n-heptane according to claim 4, characterized in that: The activation temperature is 150° C. and the activation time is 2 h.

6. The method for separating 3-methylthiophene and n-heptane according to claim 4, characterized in that: The vacuum drying temperature is 50°C.

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