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

Abstract

The invention discloses application of a miscellaneous [3] aromatic hydrocarbon crystal material in adsorptive separation of a mixture of 3-methylthiophene and n-heptane, the miscellaneous [3] aromatic hydrocarbon non-porous self-adaptive crystal material is used for adsorptive separation of the mixture of 3-methylthiophene and n-heptane, the energy consumption is low, the process is simple, and the method is suitable for industrial production. The defects of high energy consumption, complicated process, need of using a high-purity desorption agent, high cost and the like in a 3-methylthiophene and n-heptane separation technology are overcome.

Description

Technical Field

[0001] The present invention relates to the field of adsorption technology, and more specifically to the application of a hetero[3]aromatic hydrocarbon crystal material in the adsorption separation of a mixture of 3-methylthiophene and n-heptane. Background Art

[0002] 3-Methylthiophene and n-heptane exist in gasoline. Among them, with the development of social economy, the sulfur oxides produced by the combustion of 3-methylthiophene, a thiophene sulfide, have posed a great threat to the environment and human health. Therefore, the removal of pollutants 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 a fuel and solvent to improve the combustion efficiency of gasoline. In this study, 3-methylthiophene and n-heptane were used to simulate gasoline. At present, the common technology for removing 3-methylthiophene from gasoline is mainly extractive desulfurization, which consumes huge energy and is not conducive to the sustainable development of energy. In the past few decades, the 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, it is urgent 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 thiophenes from gasoline mainly relies on extractive desulfurization, membrane permeation desulfurization, etc. Chinese patent publication number CN113684052A discloses a marine fuel desulfurization extractant and an extraction desulfurization method thereof, wherein the extractant is an ionic liquid extractant, and the ionic liquid extractant includes hexadecylpyridinium chloride modified with n-hexanol and an organic acid. However, the method is complex and energy-intensive. Chinese patent publication number CN118341272A discloses a Ag-loaded + A hybrid membrane filled with PEG-ncp particles, a preparation method and a pervaporation gasoline desulfurization method thereof, using a mixed solution of thiophene and n-octane 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 the problems of complex preparation, poor film-forming properties, brittleness, and high production cost. A Chinese patent with publication number CN112473573A discloses a preparation method and application of a Pd(II)-DA-SiO2 composite aerogel. The method uses tetraethyl orthosilicate as a raw material, introduces dopamine hydrochloride and Pb 2+ However, this method has the problems of complex preparation and high cost. Summary of the invention

[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 a mixture of 3-methylthiophene and n-heptane, which has 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, need for use of high-purity desorbent and high cost.

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

[0006] The application of hetero[3]aromatic crystal material in the adsorption separation of 3-methylthiophene and n-heptane mixture, wherein the chemical structure of the hetero[3]aromatic 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]aromatic hydrocarbon crystal materials to adsorb and separate a mixture of 3-methylthiophene and n-heptane. The chemical structure of the hetero[3]aromatic hydrocarbon crystal materials is as follows:

[0009]

[0010] Optionally, the specific steps of using hetero[3]aromatic hydrocarbon crystal material to adsorb and separate the mixture of 3-methylthiophene and n-heptane are: placing the hetero[3]aromatic hydrocarbon 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 temperature of the adsorption 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 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 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] Implementing the embodiments 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 has low equipment requirements; 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 has high stability 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 The TG data of the hetero[3]arene crystalline material of the present invention after adsorption of 3-methylthiophene vapor.

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

[0021] Figure 4 The 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 crystalline material of the present invention for adsorbing 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 TG data of the hetero[3]arene crystalline material of the present invention after adsorption of 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] Fig. 9 The 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 is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

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

[0029]

[0030] Specifically, due to the difference in the molecular structure of 3-methylthiophene and n-heptane, the hetero[3]arene crystalline material can form a host-guest complex with 3-methylthiophene in a stoichiometric ratio of 1:1. The host-guest complex will gradually decomplex when heated, releasing the adsorbed 3-methylthiophene. After the desorption process is completed, it can be reused without a decrease in selectivity.

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

[0032]

[0033] In a specific embodiment, the specific steps of using hetero[3]aromatic hydrocarbon crystal materials to adsorb and separate a mixture of 3-methylthiophene and n-heptane are as follows: placing the hetero[3]aromatic hydrocarbon crystal materials 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 with the change of factors such as the sample amount 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 crystal form. Due to multiple non-covalent interactions, 3-methylthiophene in the mixture forms a host-guest complex with the hetero[3]arene, and the stoichiometric ratio of the host-guest complex is 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, under the condition of less than 80°C, the formed host-guest complex still exists stably, while the mixture of 3-methylthiophene and n-heptane adsorbed on the surface can be gradually removed. By removing the mixed vapor adsorbed on the surface, the purity of 3-methylthiophene separated by adsorption 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 will gradually be released, while the hetero[3]arene crystalline material is stable, and only the crystal form changes during the desorption process. After the desorption is completed, the regenerated hetero[3]arene crystalline material is obtained, which can continue to be used for adsorption and separation of 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 dissolved, storing the solution at 0°C overnight, filtering and collecting the precipitated crystals, vacuum drying and activating the obtained crystals once, and obtaining hetero[3]arene crystalline material.

[0043] In a specific embodiment, the activation temperature is 150° C. and the activation time is 2 h.

[0044] In a specific 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, 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]aromatic crystalline materials on individual 3-methylthiophene and n-heptane: Take three 20mL culture bottles, add 1mL of 3-methylthiophene and n-heptane respectively, name them a and b, take 20mg of the hetero[3]aromatic crystalline material prepared in Example 1 and place them in three 5mL open culture bottles, place the three open 5mL culture bottles in three 20mL culture bottles respectively, seal the 20mL culture bottles, and place them in a 25℃ 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, it is shown that 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 crystalline material, the PXRD spectrum of the hetero[3]aromatic crystalline 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 crystalline material; the spectrum of the hetero[3]aromatic crystalline 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 hardly changed, meaning that the hetero[3]aromatic crystalline 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 of hetero[3]aromatic crystalline material: Take a 20mL inoculum bottle, add 1mL 3-methylthiophene and 1mL n-heptane, named ab, take 20mg of the hetero[3]aromatic crystalline material prepared in Example 1 and place it in a 5mL open inoculum bottle, place the open 5mL inoculum bottle in the above 20mL inoculum bottle, and seal the 20mL inoculum bottle, place it in a 25℃ water bath for 24h, and place the resulting powder in a 45℃ vacuum oven for 30min.

[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]aromatic crystalline material, the PXRD spectrum of the hetero[3]aromatic crystalline material after being placed in the mixed vapor of 3-methylthiophene and n-heptane for a period of time shows an obvious change (1+ab), and the spectrum change is the same as a, which indicates that the hetero[3]aromatic crystalline 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] Recycling of hetero[3]arene crystalline material: 20 mg of hetero[3]arene crystalline 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 crystalline 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 culture bottles, add 1 mL of 3-methylthiophene and n-heptane respectively, and name them 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 culture bottles. Seal the 5 mL culture 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, it is shown that 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]aromatic crystal material, the PXRD spectrum of the hetero[3]aromatic 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]aromatic crystal material; the spectrum of the hetero[3]aromatic 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]aromatic crystal material has no adsorption capacity for n-heptane.

[0068] Example 6

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

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

[0071] The PXRD test results are as follows Figure 8 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 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 c, which indicates that the hetero[3]aromatic hydrocarbon crystal material can selectively adsorb 3-methylthiophene.

[0072] The results of headspace gas chromatography are as follows Fig. 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-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. Application of hetero[3]arene crystalline 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 a hetero[3]arene crystalline material, wherein the chemical structure of the hetero[3]arene crystalline material is as follows:

3. The method for separating 3-methylthiophene and n-heptane according to claim 1, characterized in that: The specific steps of using hetero[3]aromatic hydrocarbon crystal materials to adsorb and separate a mixture of 3-methylthiophene and n-heptane are as follows: placing the hetero[3]aromatic hydrocarbon crystal materials in a mixed vapor of 3-methylthiophene and n-heptane or a mixed solution of 3-methylthiophene and n-heptane for adsorption separation, wherein the temperature of the adsorption separation is less than 80°C.

4. The method for separating 3-methylthiophene and n-heptane according to claim 1, characterized in that: 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.

5. The method for separating 3-methylthiophene and n-heptane according to claim 1, characterized in that: The method of heating and desorption is used to remove the 3-methylthiophene adsorbed and complexed by the hetero[3]aromatic hydrocarbon crystal material, thereby achieving the regeneration of the hetero[3]aromatic hydrocarbon crystal material; the temperature of the heating and desorption is 80°C to 100°C.

6. The method for separating 3-methylthiophene and n-heptane according to claim 1, characterized in that: The method for preparing 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 of the mixture is 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.

7. The method for separating 3-methylthiophene and n-heptane according to claim 6, characterized in that: The activation temperature is 150° C. and the activation time is 2 h.

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

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