Application of bromoethyl pillar [5] arene crystal material as adsorbent in n-butyraldehyde adsorption

Abstract

The invention relates to application of a bromoethyl pillar [5] arene crystal material as an adsorbent in n-butyraldehyde adsorption, and belongs to the technical field of adsorption separation materials. The bromoethyl pillar [5] arene crystal material is used as an adsorbent to efficiently adsorb n-butyraldehyde, the structural formula of the bromoethyl pillar [5] arene crystal material is shown in the specification, the chemical property of the bromoethyl pillar [5] arene crystal material is stable, n-butyraldehyde can be separated from gaseous butyraldehyde isomers with the purity of 99.1%, and the bromoethyl pillar [5] arene crystal material can be recycled without losing any performance. Moreover, the separation method of the butyraldehyde isomer is simple in process operation and low in equipment requirement; in addition, rectification operation is not needed, energy consumption is low, energy is saved, and the production cost of n-butyraldehyde and isobutyraldehyde is reduced.

Description

Technical Field

[0001] This invention relates to the application of bromoethyl column[5] aromatic crystalline material as an adsorbent in the adsorption of n-butyraldehyde, and belongs to the field of adsorption separation material technology. Background Technology

[0002] Butyraldehyde and its isomers are important solvents and chemical intermediates, widely used in the production of fragrances, coatings, plastics, and rubber, possessing extremely high application value and an indispensable position. Therefore, efficient separation of butyraldehyde isomers is crucial in industrial production processes, and its separation methods are receiving increasing attention. The synthesis of butyraldehyde via propylene carbonylation is an advanced process that is both efficient and environmentally friendly; however, the products generated by this method usually also contain n-butyraldehyde (…). n -BA) and isobutyraldehyde ( i -BA). Therefore, the effective separation of these two butyraldehyde isomers is particularly important. Currently, industrially, distillation and rectification are the main methods for separating butyraldehyde isomers from mixtures. However, due to... n -BA and i -BA have similar physical properties, especially their boiling points (n-butyraldehyde: 348.85 K, isobutyraldehyde: 337.65 K) and polarities, making traditional distillation methods often energy-intensive for separation. Currently, porous materials such as inorganic adsorbents, covalent organic frameworks, and metal-organic frameworks show great promise for isomer separation; however, these materials generally suffer from poor stability and low reusability, limiting their further application.

[0003] Patent CN 116920631A discloses a zirconium-based metal-organic framework membrane for separating hydrocarbon isomers, its preparation method, and its application. Based on the differences in molecular dynamics diameters of hydrocarbon isomers, a zirconium-based metal-organic framework membrane with a molecular size sieve window between hydrocarbon isomers with the same number of carbon atoms is selected for separating hydrocarbon isomers; alternatively, a polycrystalline membrane with crystallographic pore sizes between the substances to be separated is used. This zirconium-based metal-organic framework membrane overcomes the difficulty in separating large molecular isomers, but metal-organic frameworks are unstable under high temperature or acid / alkali conditions. Patent CN117861611A discloses a method for preparing an adsorbent for separating and purifying m- and p-cresol isomers. This method involves adsorption and desorption processes on a zeolite molecular sieve adsorbent. This patent involves loading a shaped adsorbent into a countercurrent simulated moving bed, continuously introducing m- and p-cresol material and a desorbent, and continuously collecting the extract and raffinate material to ultimately obtain high-purity m- and p-cresol products. This is a highly efficient method for separating single cresol isomers. However, molecular sieve adsorbents have limited adsorption capacity, and their preparation requires high-temperature calcination, resulting in significant energy consumption.

[0004] Therefore, developing a method for separating butyraldehyde isomers that combines high stability, high adsorption capacity, and low energy consumption has become an important research direction. Summary of the Invention

[0005] In response to the problems of high energy consumption, complicated process and need for high-purity desorbent in the existing butyraldehyde isomer separation technology, this invention provides the application of bromoethyl column[5] aromatic crystalline material as adsorbent in the adsorption of n-butyraldehyde. Specifically, it provides a method for adsorbing and separating butyraldehyde isomers using bromoethyl column[5] aromatic non-porous adaptive crystalline material, which has low energy consumption and simple process.

[0006] Due to the difference in molecular size between n-butyraldehyde and isobutyraldehyde, the bromoethyl column [5] aromatic crystal material can selectively form a host-guest complex with n-butyraldehyde in a stoichiometric ratio of 1:1 in the butyraldehyde isomer. This host-guest complex gradually de-complexes upon heating, releasing the adsorbed n-butyraldehyde. The bromoethyl column [5] aromatic crystal material is stable at the desorption temperature and can be reused after the desorption process is complete, without a decrease in selectivity.

[0007] The application of bromoethyl column[5] aromatic crystalline material as an adsorbent in the adsorption of n-butyraldehyde, the chemical structural formula of the bromoethyl column[5] aromatic crystalline material is shown below: .

[0008] The bromoethyl columnar aromatic crystalline material described in this invention[5] can be prepared by methods disclosed in the prior art.

[0009] Preferably, the bromoethyl[5]arene crystal material is prepared by the following method: bromoethyl[5]arene is placed in acetone, heated to boiling, and acetone is added dropwise until completely dissolved. The solution is stored at 0°C overnight, the precipitated crystals are collected by filtration, the obtained crystals are dried under vacuum at 50°C, and activated at 150°C for 2 h to obtain the final product.

[0010] Another objective of this invention is to provide a method for separating butyraldehyde isomers, wherein the separation method involves using a bromoethyl column[5] aromatic crystal material to selectively adsorb n-butyraldehyde in a mixture of n-butyraldehyde / isobutyraldehyde vapor for a certain period of time at room temperature, thereby achieving the separation of n-butyraldehyde and isobutyraldehyde.

[0011] The bromoethyl columnar [5] aromatic crystalline material described in this invention undergoes a change in crystal form during the adsorption of n-butyraldehyde. Due to multiple non-covalent interactions, n-butyraldehyde in the mixed vapor will form a host-guest complex with the bromoethyl columnar [5] aromatic, and the stoichiometric ratio of the host-guest complex is 1:1.

[0012] In the above technical solution, the placement time is ≥5 min.

[0013] The bromoethyl column[5] aromatic crystal material described in this invention requires as little as 5 minutes to adsorb n-butyraldehyde.

[0014] In the above technical solution, the separation method further includes: after selectively adsorbing n-butyraldehyde, removing the mixture of butyraldehyde isomers adsorbed on the surface of the bromoethyl column[5] aromatic crystal material by vacuum heating or reduced pressure heating.

[0015] Furthermore, the vacuum heating or reduced pressure heating temperature is ≤40℃, and the time is 30~40 min.

[0016] More preferably, the vacuum heating or reduced pressure heating is performed at a temperature of 35-40°C for 30 minutes.

[0017] At ≤40℃, the host-guest complex formed by n-butyraldehyde and bromoethyl column[5] aromatic hydrocarbon remains stable, while the mixture of butyraldehyde isomers adsorbed on the surface of bromoethyl column[5] aromatic hydrocarbon can be gradually removed. By removing the mixed vapor adsorbed on the surface, the purity of the n-butyraldehyde separated by adsorption can be further improved.

[0018] In the above technical solution, the bromoethyl column[5] aromatic crystal material that selectively adsorbs n-butyraldehyde is desorbed by vacuum heating to regenerate the bromoethyl column[5] aromatic crystal material.

[0019] Furthermore, the vacuum heating temperature is 80~100℃, and the time is 4~5 hours.

[0020] Within a temperature range of 80 to 100°C, the host-guest complex formed by n-butyraldehyde and bromoethyl[5]arene is unstable. The adsorbed n-butyraldehyde molecules will be gradually released, while the bromoethyl[5]arene crystal material remains stable, with only a change in crystal form. After desorption, the individual bromoethyl[5]arene crystal material can be obtained and used to continue adsorbing and separating butyraldehyde isomers for the next cycle.

[0021] This invention utilizes bromoethyl column[5] aromatic crystal material to achieve efficient separation of n-butyraldehyde from gaseous butyraldehyde isomers with a purity of 99.1% and in a short time (5 min).

[0022] The beneficial effects of this invention are as follows: This invention uses bromoethyl column[5] aromatic crystalline material as an adsorbent to efficiently adsorb n-butyraldehyde. The bromoethyl column[5] aromatic crystalline material has stable chemical properties and can not only separate n-butyraldehyde from gaseous butyraldehyde isomers with a purity of 99.1%, but can also be recycled without any loss of performance. Furthermore, the separation method of butyraldehyde isomers described in this invention is simple to operate and has low equipment requirements; in addition, it does not require distillation, has low energy consumption, saves energy, and reduces the production cost of n-butyraldehyde and isobutyraldehyde. Attached Figure Description

[0023] Figure 1 The image shows the PXRD data of the bromoethyl columnar aromatic crystalline material obtained in Example 1 [5].

[0024] Figure 2 The PXRD data results of n-butyraldehyde and isobutyraldehyde vapor adsorption by the bromoethyl column[5] aromatic crystal material in Example 2 are shown.

[0025] Figure 3 The image shows the PXRD data of the bromoethyl column[5] aromatic crystal material in Example 3 after adsorption of a mixture of n-butyraldehyde and isobutyraldehyde isomers by vapor.

[0026] Figure 4 The bromoethyl column[5] aromatic crystal material in Example 3 was used to react with the mixed vapor of n-butyraldehyde and isobutyraldehyde isomers ( v : v = 1 : 1) Headspace gas chromatogram after adsorption.

[0027] Figure 5 The diagram shows the cyclic performance of the bromoethyl column[5] aromatic crystal material in Example 4 for the adsorption of mixed vapors of n-butyraldehyde and isobutyraldehyde isomers.

[0028] Figure 6 The graph shows the time dependence of the adsorption of n-butyraldehyde and isobutyraldehyde isomers by the bromoethyl column[5] aromatic crystal material in Example 5. Detailed Implementation

[0029] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0030] 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.

[0031] Example 1 The preparation method of bromoethyl[5]arene crystal material includes the following steps: weigh 2 g of bromoethyl[5]arene and place it in 20 mL of acetone, heat to boiling, add acetone dropwise until completely dissolved, store the solution at 0℃ overnight, filter and collect the precipitated crystals, dry the obtained crystals under vacuum at 50℃, activate at 150℃ for 2 h to obtain a white powder, which is denoted as BrP5. α .

[0032] The characterization data of the product prepared in this embodiment are as follows: BrP5 α , 1 H NMR (600 MHz, CDCl3, 298 K, ppm) δ 6.91 (s, 10 H), 4.23 (q, 20 H), 3.84 (s, 10 H), 3.63 (t, 20 H).

[0033] The chemical structural formula of the bromoethyl column[5] aromatic crystalline material is as follows:

[0034] The PXRD test results of the product prepared in this embodiment are as follows: Figure 1 As shown, it can be seen that the obtained bromoethyl columnar aromatic crystalline material [5] has good crystallinity.

[0035] Example 2 The bromoethyl column[5] aromatic crystal material obtained in Example 1 adsorbed n-butyraldehyde vapor and isobutyraldehyde vapor respectively: Add 1 mL of n-butyraldehyde and isobutyraldehyde to two separate 20 mL bottles, and name them BrP5. α - n -BA and BrP5 α - i -BA. Then, 5 mg of the bromoethyl column[5] aromatic crystal material prepared in Example 1 was placed into two 5 mL open bottles, and these two open bottles were placed into bottles containing n-butyraldehyde and isobutyraldehyde. After sealing, the two bottles were placed in a 25°C water bath for 24 h to carry out the adsorption experiment. After the experiment, the bromoethyl column[5] aromatic crystal material that adsorbed n-butyraldehyde and isobutyraldehyde vapors was named BrP5. α - n -BA and BrP5 α - i -BA.

[0036] The characterization data of the product prepared in this embodiment are as follows: BrP5 α - n -BA, 1H NMR (400 MHz, CDCl3) δ 9.76 (s, 1 H), 6.91 (s, 10 H), 4.23 (t, 20 H), 3.84 (s, 10 H), 3.63 (t, 20 H), 2.41–2.37 (m, 2 H), 1.65 (d, 2 H), 0.96 (t, 3 H); BrP5 α - i -BA, 1 H NMR (400 MHz, CDCl3) δ 9.64 (d, 1 H), 6.91 (s, 10 H), 4.23 (t, 20 H), 3.84 (s, 10 H), 3.63 (t, 20 H), 2.45–2.42 (m, 1 H), 1.13 (d, 6 H).

[0037] 1 1H NMR results showed that the bromoethyl column[5] aromatic crystal material had different degrees of adsorption effect on n-butyraldehyde and isobutyraldehyde.

[0038] The PXRD test results of the product prepared in this embodiment are as follows: Figure 2 As shown, it can be seen that the PXRD spectrum of the bromoethyl column[5] aromatic crystal material after being placed in n-butyraldehyde and isobutyraldehyde vapor for a period of time shows a significant change compared to the PXRD spectrum of the initially activated bromoethyl column[5] aromatic crystal material. This phenomenon indicates that its cell parameters have changed, which further indicates that n-butyraldehyde and isobutyraldehyde have been adsorbed into the bromoethyl column[5] aromatic crystal material. It can be seen that the bromoethyl column[5] aromatic crystal material has a significant adsorption capacity for both n-butyraldehyde and isobutyraldehyde.

[0039] Example 3 The bromoethyl column[5] aromatic crystal material obtained in Example 1 reacts with the mixed vapors of n-butyraldehyde and isobutyraldehyde ( v : v Adsorption at a ratio of 1:1: 1 mL of n-butyraldehyde and 1 mL of isobutyraldehyde were mixed at a volume ratio of 1:1 and added to a 20 mL bottle. Then, 5 mg of the bromoethyl column [5] aromatic crystal material prepared in Example 1 was placed in a 5 mL open bottle and placed in a bottle containing the mixture of n-butyraldehyde and isobutyraldehyde. After sealing, the bottle was placed in a 25°C water bath for 24 h. After the 24 h test, the powder obtained was dried in a 40°C vacuum oven for 30 min and named BrP5. α - n -BA / i -BA.

[0040] The characterization data of the product prepared in this embodiment are as follows: BrP5 α - n -BA / i -BA, 1 H NMR (400 MHz, CDCl3) δ 9.76 (s, 1 H), 6.91 (s, 10 H), 4.23 (t, 20 H), 3.84 (s, 10 H), 3.63 (t, 20 H), 2.41–2.37 (m, 2 H), 1.65 (d, 2 H), 0.96 (t, 3 H).

[0041] The above characterization data only showed the signal of the hydrogen atom corresponding to n-butyraldehyde, which indicates that the bromoethyl column[5] aromatic crystal material can selectively adsorb n-butyraldehyde.

[0042] The PXRD test results of the product prepared in this embodiment are as follows: Figure 3 As shown, it can be seen that the PXRD spectrum of the bromoethyl column[5] aromatic crystal material changed after being placed in a mixed vapor of n-butyraldehyde and isobutyraldehyde for a period of time, compared to the PXRD spectrum of the initially activated bromoethyl column[5] aromatic crystal material. Furthermore, the spectrum changes were consistent with those of BrP5. α - n -BA is the same, which indicates that the bromoethyl column[5] aromatic crystal material can selectively adsorb n-butyraldehyde.

[0043] The headspace gas chromatography results of the product prepared in this embodiment are as follows: Figure 4 As shown, the results indicate that the bromoethyl column[5] aromatic crystal material can selectively adsorb n-butyraldehyde with a selectivity of 99.1%.

[0044] Example 4 Experimental verification of the reusability of bromoethyl columnar [5] aromatic crystal material: 5 mg of bromoethyl columnar [5] aromatic crystal material saturated with n-butyraldehyde was heated in a vacuum oven at 100°C for 2 h to obtain regenerated bromoethyl columnar [5] aromatic material. 5 mg of the regenerated bromoethyl columnar [5] aromatic crystal material was then repeated in Example 3. The results are as follows: Figure 5 As shown, it can be seen that the selectivity did not decrease after being used 5 times.

[0045] Example 5 Verification of the efficiency of bromoethyl column [5] aromatic crystal material in separating butyraldehyde isomers: 1 mL of n-butyraldehyde and 1 mL of isobutyraldehyde were mixed at a volume ratio of 1:1 and added to a 20 mL bottle. Then, 5 mg of bromoethyl column [5] aromatic crystal material prepared in Example 1 was placed in a 5 mL open bottle and placed in a bottle containing a mixture of n-butyraldehyde and isobutyraldehyde. After sealing, the bottle was placed in a 25°C water bath for adsorption for 0~24 h, and 8 time points were tested. The bromoethyl column [5] aromatic crystal material obtained after adsorption for different times was placed in a 40°C vacuum oven and dried for 30 min. Then, the adsorption amount of butyraldehyde isomers was measured and time-dependent curves were plotted. The results are as follows. Figure 6 As shown, it can be seen that the bromoethyl column[5] aromatic crystal material can selectively adsorb n-butyraldehyde at 5 min.

Claims

1. Use of a bromoethyl pillar[5]arene crystal material as an adsorbent in the adsorption of n-butyraldehyde, characterized in that: The chemical structural formula of the bromoethyl pillar[5]arene crystal material is as follows: 。 2. Use according to claim 1, characterized in that: The bromoethyl pillar[5]arene crystal material is prepared by the following method: placing bromoethyl pillar[5]arene in acetone, heating to boiling, adding acetone dropwise until completely dissolved, placing the solution in a 0°C refrigerator overnight, filtering to collect the precipitated crystals, and drying the obtained crystals at 50°C under vacuum, and activating at 150°C for 2 hours.

3. A method for separating butyraldehyde isomers, characterized by: At room temperature, the bromoethyl pillar[5]arene crystal material selectively adsorbs n-butyl aldehyde in n-butyl aldehyde / isobutyl aldehyde mixed steam for a certain time to separate n-butyl aldehyde and isobutyl aldehyde.

4. The separation method of claim 3, wherein: The placement time is ≥5 min.

5. The separation method of claim 3, wherein: The separation method further comprises: after selectively adsorbing n-butyl aldehyde, removing the adsorbed butyl aldehyde isomer mixture on the surface of the bromoethyl pillar[5]arene crystal material by vacuum heating or reduced pressure heating.

6. The separation method of claim 5, wherein: The temperature of the vacuum heating or reduced pressure heating is ≤40°C, and the time is 30-40 min.

7. The separation method of claim 6, wherein: The temperature of the vacuum heating or reduced pressure heating is 35-40°C, and the time is 30 min.

8. The separation method of claim 3, wherein: The bromoethyl pillar[5]arene crystal material selectively adsorbing n-butyl aldehyde is subjected to vacuum heating to desorb the adsorbed n-butyl aldehyde, thereby regenerating the bromoethyl pillar[5]arene crystal material.

9. The separation method of claim 8, wherein: The temperature of the vacuum heating is 80-100°C, and the time is 4-5 h.

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