Electron-rich aryl substituted thioester-based carbon dioxide absorbents

Abstract

The application discloses an electron-rich aryl-substituted thioester type carbon dioxide absorbent, and the carbon dioxide composite absorbent prepared by introducing the electron-rich aryl-substituted thioester has high carbon dioxide absorption rate and high carbon dioxide desorption rate, and the carbon dioxide desorption temperature is reduced, and the problems of small absorption capacity and difficult desorption of a single ethanol amine absorbent are solved.

Description

Technical Field

[0001] This invention relates to a technology in the field of carbon dioxide capture, separation and purification, specifically an electron-rich aryl substituted thioester carbon dioxide absorbent. Background Technology

[0002] Chemical absorption methods, represented by organic amines, capture carbon dioxide through a chemical reaction between the absorbent and carbon dioxide. Desorption can occur under specific conditions (such as high temperature and low pressure), separating high concentrations of carbon dioxide gas while simultaneously regenerating the absorbent solution. Organic amine absorption is currently the dominant carbon dioxide capture technology; however, it remains hampered by high desorption and regeneration energy consumption. Finding a suitable absorbent is the core issue in carbon dioxide capture. In chemical absorption methods, the absorbent determines the quality of absorption and desorption performance. Traditional single absorbents rarely possess excellent absorption and desorption properties simultaneously. High absorption rates and large saturation loadings of absorbents are often accompanied by high desorption energy consumption and difficult regeneration; conversely, low regeneration energy consumption may be associated with slow absorption rates and small saturation loadings. Summary of the Invention

[0003] This invention addresses the shortcomings of existing absorbents, such as poor absorption rate and insufficient overall absorption capacity for carbon dioxide. It proposes an electron-rich aryl-substituted thioester carbon dioxide absorbent. By introducing electron-rich aryl-substituted thioesters, the prepared carbon dioxide composite absorbent possesses both high carbon dioxide absorption rate and high desorption rate, while simultaneously reducing the carbon dioxide desorption temperature. This improves upon the shortcomings of single ethanolamine absorbents, such as low absorption capacity and difficulty in desorption.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to an electron-rich aryl-substituted thioester carbon dioxide absorbent, which is obtained by mixing an electron-rich aryl-substituted thioester, an alkanolamine, and a stabilizer.

[0006] The structural formula of the electron-rich aryl substituted thioester is as follows: , where: R 1 It is methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, methoxy, ethoxy, tert-butoxy, dimethylamino, or trimethylsilyl; R 2 It is hydrogen, hydroxyethyl, isopropyl, n-butyl, phenyl, cyclohexyl or benzyl, preferably thio-4-methoxybenzoic acid, butyl thio-4-tert-butoxybenzoate, hydroxyethyl thio-4-dimethylaminobenzoate, benzyl thio-4-methoxybenzoate or a combination thereof.

[0007] The alkanolamine is 2-aminoethanol (MEA), di(2-hydroxyethyl)amine (DEA), N-(2-hydroxyethyl)ethylenediamine (AEEA) or a combination thereof, preferably 2-aminoethanol (MEA) and N-(2-hydroxyethyl)ethylenediamine (AEEA) or a combination thereof.

[0008] The stabilizer is potassium acetate, potassium carbonate, sodium metavanadate, sodium sulfite, sodium citrate, pyridine, N-methylmorpholine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or a combination thereof, preferably sodium metavanadate, sodium citrate and N-methylmorpholine or a combination thereof.

[0009] The electron-rich aryl substituted thioester accounts for 5%-40% of the total mass of the absorbent product, the alcohol amine accounts for 5%-40% of the mass, the stabilizer accounts for 0.5%-10% of the mass, and the remaining component is water.

[0010] The preferred mass fraction of the electron-rich aryl substituted thioester in the total mass of the absorbent product is 10%-25%, the preferred mass fraction of the alkanolamine is 20%-30%, the preferred mass fraction of the stabilizer is 1%-3%, and the remaining component is water.

[0011] The composite absorbent has an absorption temperature of 288-333 K and a desorption temperature of 353-423 K, preferably an absorption temperature of 298-313 K and a desorption temperature of 368-398 K.

[0012] Compared with existing technologies, this invention enhances the internal mass transfer of the system by introducing an electron-rich aryl-substituted thioester with tunable electrons into the carbon dioxide absorbent, significantly reducing the energy barrier of the carbon dioxide transfer process, and achieving rapid adsorption and mild desorption of carbon dioxide, making it suitable for industrial applications. Detailed Implementation Example 1

[0013] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 20 wt% 2-aminoethanol, 20 wt% thio-4-methoxybenzoic acid, 1 wt% sodium metavanadate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 2

[0014] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 20 wt% 2-aminoethanol, 10 wt% phenyl thio-4-ethylbenzoate, 1 wt% sodium metavanadate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 3

[0015] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 25 wt% 2-aminoethanol, 15 wt% butyl thio-4-ethoxybenzoate, 2 wt% sodium metavanadate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 4

[0016] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 30 wt% N-(2-hydroxyethyl)ethylenediamine, 15 wt% butyl thio-4-tert-butoxybenzoate, 2 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 5

[0017] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 20 wt% N-(2-hydroxyethyl)ethylenediamine, 20 wt% isopropyl thio-4-tert-butoxybenzoate, 2 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 6

[0018] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 20 wt% 2-aminoethanol, 10 wt% benzyl thio-4-isopropylbenzoate, 1 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 7

[0019] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 30 wt% 2-aminoethanol, 10 wt% benzyl thio-4-tert-butylbenzoate, 2 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 8

[0020] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 20 wt% N-(2-hydroxyethyl)ethylenediamine, 15 wt% benzyl thio-4-methoxybenzoate, 1 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 9

[0021] The electron-rich aryl substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 25 wt% 2-aminoethanol, 15 wt% phenyl thio-4-cyclohexylbenzoate, 2 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 10

[0022] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 25 wt% N-(2-hydroxyethyl)ethylenediamine, 10 wt% hydroxyethyl thio-4-dimethylaminobenzoate, 3 wt% sodium metavanadate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 11

[0023] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 20 wt% N-(2-hydroxyethyl)ethylenediamine, 15 wt% hydroxyethyl thio-4-trimethylsilylbenzoate, 2 wt% sodium metavanadate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 12

[0024] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 25 wt% 2-aminoethanol, 15 wt% isopropyl thio-4-phenoxybenzoate, 2 wt% sodium metavanadate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 13

[0025] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 30 wt% N-(2-hydroxyethyl)ethylenediamine, 15 wt% phenyl thio-4-methylbenzoate, 1 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 14

[0026] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 25 wt% 2-aminoethanol, 15 wt% cyclohexyl thio-4-methoxybenzoate, 2 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1. Example 15

[0027] The electron-rich aryl-substituted thioester carbon dioxide absorbent involved in this embodiment is prepared by uniformly mixing 30 wt% N-(2-hydroxyethyl)ethylenediamine, 15 wt% butyl thio-4-methylbenzoate, 1 wt% sodium citrate, and water. Its carbon dioxide absorption and desorption performance is shown in Table 1.

[0028] The present invention tests the performance indicators of the absorbents prepared in the above embodiments in the following ways, specifically including:

[0029] Step 1: Add 1000 grams of the prepared composite absorbent to the carbon dioxide absorption reactor. Turn on the constant temperature stirring device and set the absorption temperature between 298 and 313 K. Once the reactor reaches the set temperature, open the carbon dioxide cylinder and monitor and regulate the gas flow rate using a flow controller. Carbon dioxide enters the reactor and reacts with the absorbent. Uniform stirring ensures even gas-liquid contact. The remaining gas after the gas-liquid reaction exits the reactor and enters the flow meter.

[0030] Step 2: The flow meter automatically records the instantaneous flow data every 5 seconds. When the readings of the flow meters at both ends are the same, it is considered that the absorption is saturated. The absorption rate is calculated from the difference in the values ​​of the flow meters at both ends. , where: v abs The absorption rate is expressed in mol carbon dioxide·(mol amine·min). -1 Q in The inlet gas flow rate of the reactor is expressed in m³ / s. 3 ·min -1 Q out The inlet gas flow rate of the reactor is expressed in m³ / s. 3 ·min -1 P is atmospheric pressure, in Pa; n is the amount of alkanolamine in the absorbent, in mol; R is the gas constant, in J·(mol·K). -1 T represents the temperature of the absorbent liquid, in K.

[0031] Step 3: After the absorption experiment, perform acid-base titration on the rich solution to determine the carbon dioxide loading C0. Plot the change of carbon dioxide loading over time, and perform linear fitting on the approximately linear portion of the initial absorption phase. The slope of the resulting line is approximately the initial absorption rate of the absorbent.

[0032] Step 4: The desorption process of the absorbent is as follows: Take 1000 grams of the carbon dioxide-rich solution into the reactor, open the nitrogen cylinder, and use the flow controller to monitor and regulate the gas flow rate to purge the rich solution. Set the desorption temperature between 368 and 398 K, and maintain the reactor temperature stable at the set temperature to carry out the desorption reaction. The absorbent will release carbon dioxide again under high temperature and nitrogen. When the flow meter reading at the outlet no longer changes and is equal to the nitrogen flow rate at the inlet, it indicates that the carbon dioxide has been completely released, and the desorption experiment is complete.

[0033] Step 5: Perform acid-base titration on the desorbed lean solution to determine the carbon dioxide loading C1. Desorption rate. Where: C0 is the carbon dioxide loading of the enriched solution after absorption, in g·L. -1 C1 represents the carbon dioxide loading of the lean solution after desorption, in g·L. -1.

[0034] Table 1. Carbon dioxide absorption and desorption performance of thioester composite absorbents

[0035]

[0036] Compared with existing technologies, this invention introduces an electron-rich aryl-substituted thioester with tunable electron properties into the carbon dioxide absorbent. By employing a thioester composite strategy, on the one hand, the high-energy thioester bond has a kinetic advantage in binding carbon dioxide; on the other hand, the bonding between the composite absorbent and carbon dioxide is in dynamic change, which enhances the internal mass transfer of the system, significantly reduces the energy barrier of the carbon dioxide transfer process, and achieves rapid adsorption and mild desorption of carbon dioxide, making it suitable for industrial applications.

Claims

1. An electron-rich aryl-substituted thioester carbon dioxide absorbent, characterized in that, It is obtained by mixing an electron-rich aryl-substituted thioester, an alkanolamine, and a stabilizer; The structural formula of the electron-rich aryl substituted thioester is as follows: , where: R 1 It is methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, methoxy, ethoxy, tert-butoxy, dimethylamino, or trimethylsilyl; R 2 It can be hydrogen, hydroxyethyl, isopropyl, n-butyl, phenyl, cyclohexyl, or benzyl; The alkanolamine is 2-aminoethanol (MEA), di(2-hydroxyethyl)amine (DEA), N-(2-hydroxyethyl)ethylenediamine (AEEA), or a combination thereof; The stabilizer is potassium acetate, potassium carbonate, sodium metavanadate, sodium sulfite, sodium citrate, pyridine, N-methylmorpholine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or a combination thereof; The electron-rich aryl substituted thioester accounts for 5%-40% of the total mass of the absorbent product, the alcohol amine accounts for 5%-40% of the mass, the stabilizer accounts for 0.5%-10% of the mass, and the remaining component is water.

2. The electron-rich aryl-substituted thioester carbon dioxide absorbent according to claim 1, characterized in that, The electron-rich aryl substituted thioesters are thio-4-methoxybenzoic acid, thio-4-tert-butoxybenzoic acid butyl ester, thio-4-dimethylaminobenzoic acid hydroxyethyl ester, thio-4-methoxybenzoic acid benzyl ester, or a combination thereof.

3. The electron-rich aryl-substituted thioester carbon dioxide absorbent according to claim 1, characterized in that, The alkanolamine is 2-aminoethanol (MEA) and N-(2-hydroxyethyl)ethylenediamine (AEEA) or a combination thereof.

4. The electron-rich aryl-substituted thioester carbon dioxide absorbent according to claim 1, characterized in that, The stabilizer used is sodium metavanadate, sodium citrate, and N-methylmorpholine or a combination thereof.

5. The electron-rich aryl-substituted thioester carbon dioxide absorbent according to claim 1, characterized in that, The electron-rich aryl substituted thioester accounts for 10%-25% of the total mass of the absorbent product, the alcohol amine accounts for 20%-30% of the mass, the stabilizer accounts for 1%-3% of the mass, and the remaining component is water.

6. The electron-rich aryl-substituted thioester carbon dioxide absorbent according to claim 1, characterized in that, The absorption temperature of the absorbent is 288-333 K, and the desorption temperature is 353-423 K.

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