Hindered aliphatic polyamine solutions for capturing carbon dioxide and applications
By embedding quaternary carbon steric groups into the framework of fatty polyamine absorbents, thermal and oxidative degradation are inhibited, solving the problem of easy loss of alkanolamine solutions and achieving efficient and low-energy carbon dioxide capture.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN UNIV OF TECH
- Filing Date
- 2024-05-28
- Publication Date
- 2026-06-09
AI Technical Summary
Existing amine solutions are prone to thermal and oxidative degradation during carbon dioxide capture, leading to decreased absorption efficiency and additional cost losses. How to construct a highly efficient absorption system resistant to thermal and oxidative degradation through structural modification has become a challenge.
By employing a sterically hindered fatty polyamine solution, quaternary carbon sterically hindered groups are inserted into the fatty polyamine absorbent skeleton to suppress side reactions such as dealkylation, Hoffmann elimination, hydroxyl oxidation, and Cope elimination, thereby improving the stability and regeneration efficiency of the absorbent.
Steric hindered fatty polyamine solutions maintain carbon dioxide absorption performance at high temperatures, reduce regeneration energy consumption, achieve efficient carbon dioxide capture, and reduce material and labor costs.
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Abstract
Description
Technical Field
[0001] This invention relates to a class of sterically hindered fatty polyamine solutions for capturing carbon dioxide and their applications. Background Technology
[0002] Currently, amine liquid chemical absorption (reaction formula 1), represented by alkanolamine solutions, is the most mature carbon capture strategy, possessing advantages such as high selectivity, rapid response, wide applicability, and low equipment cost. Multiple demonstration units have been installed and put into operation both domestically and internationally. However, due to the inherent molecular structure of alkanolamine absorbents, the chemical processes of thermal degradation and oxidative degradation into small-molecule volatile organic amines during regeneration cannot be avoided at the source. This necessitates the periodic replenishment of amine liquid in carbon capture facilities, resulting in additional cost losses and environmental pollution. Therefore, how to structurally modify inexpensive and readily available organic amine molecules through simple and easy-to-implement functionalization strategies to construct a highly efficient absorption system with resistance to thermal and oxidative degradation has become one of the urgent problems to be solved in the practical application of carbon dioxide capture technology.
[0003] Reaction 1:
[0004]
[0005] Degradation studies on alkanolamine absorbents show that during thermal degradation, alkanolamine molecules mainly undergo side reactions such as dealkylation and Hoffmann elimination; during oxidative degradation, they mainly undergo side reactions such as hydroxyl oxidation and Cope elimination. Both types of degradation processes of alkanolamine molecules produce volatile small-molecule organic amines, leading to decreased absorption efficiency and additional environmental pollution. Therefore, developing structural functionalization methods for organic amine carbon dioxide absorbents to enhance their anti-degradation performance at the molecular level is crucial, and can achieve the dual benefits of saving material and labor costs. Summary of the Invention
[0006] The purpose of this invention is to provide a type of low-loss, low-energy-consumption, sterically hindered fatty polyamine solution for capturing carbon dioxide and its application, in order to solve the problems of high energy consumption and easy thermal degradation and oxidative degradation and deactivation of existing alcohol amine solution absorption systems.
[0007] The technical solution of the present invention is as follows:
[0008] A type of sterically hindered fatty polyamine solution for capturing carbon dioxide comprises, by weight, 20-40 parts of sterically hindered fatty polyamine as an absorbent and 60-80 parts of water, wherein the fatty polyamine in the absorbent has a structural framework of N-type carbon intercalated with sterically hindered quaternary carbon. 1 -(2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine or N 1-(3-amino-2,2-dimethylpropyl)-2,2-dimethylpropyl-1,3-diamine.
[0009] Furthermore, the sterically hindered fatty polyamine is one or a mixture of two or more of the compounds shown in formula (I) and formula (II);
[0010]
[0011] Among them, R 1 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl;
[0012] R 2 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl;
[0013] R 3 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl;
[0014] R 4 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl;
[0015] R 5 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl;
[0016] R 6 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl.
[0017] Furthermore, the preparation method of the sterically hindered fatty polyamine absorbent includes the following steps:
[0018] S1. Bis(2-chloro-2-methylpropyl)amine hydrochloride, bis(2-chloro-2-methylpropyl)methylamine hydrochloride, bis(3-chloro-2,2-dimethylpropyl)amine hydrochloride, or bis(3-chloro-2,2-dimethylpropyl)methylamine hydrochloride, designated as component 1, and ammonia, methylamine solution, ethylamine solution, n-propylamine, isopropylamine, n-butylamine, isobutylamine, or 2-aminoethanol, designated as component 2, are sequentially added to a high-pressure reactor and reacted at 60–90°C for 8–14 h; the molar ratio of component 1 to component 2 is 1:4–40.
[0019] After soaking S2 in an ice-water bath in a high-pressure reactor for 0.5–1 h, the reaction mixture is transferred to a wide-mouth bottle cooled in an ice-water bath. NaOH is added in batches with stirring. The molar ratio of NaOH to component 1 is 4–16:1, and the stirring time is 10–40 min. Then, the entire mixture is transferred to a separatory funnel and allowed to stand. The lower aqueous phase is released, and the upper aqueous organic phase is collected.
[0020] S3 extracts the upper aqueous organic phase with dichloromethane. After combining the dichloromethane phases, the mixture is dried with anhydrous Na2SO4 for 8–14 h. The dichloromethane solvent is removed by rotary evaporation, and then the mixture is distilled under reduced pressure to obtain one of the compounds shown in formula (I) and formula (II).
[0021] The above-mentioned sterically hindered fatty polyamine solution is used for carbon dioxide capture. This sterically hindered fatty polyamine solution is applied to the decarbonization treatment of industrial waste gas and energy gas containing carbon dioxide.
[0022] Furthermore, industrial waste gas and energy gas containing carbon dioxide originate from power plant flue gas, oil refinery tail gas, steel plant tail gas, cement plant tail gas, chemical plant tail gas, water gas, biogas, natural gas, and carbonate ore decomposition gas.
[0023] Furthermore, the operating conditions for the sterically hindered fatty polyamine solution are as follows: gas pressure of 0.1–0.5 MPa, carbon dioxide concentration of 5%–80%, absorption temperature of 20.0–60.0 °C, absorption time of 0.1–0.8 h, regeneration temperature of 80–130 °C, and regeneration time of 0.1–0.8 h.
[0024] This invention specifically designs the absorbent structure at the molecular level by embedding quaternary carbon steric hindrance groups into the fatty polyamine absorbent skeleton: 1) On the one hand, it can inhibit thermal degradation and oxidative degradation processes represented by side reactions such as dealkylation, Hoffmann elimination, hydroxyl oxidation and Cope elimination, thereby enhancing the stability of the absorbent; 2) On the other hand, it can utilize the steric hindrance groups to regulate the interaction strength between the amine group and carbon dioxide, thereby improving the regeneration efficiency of the absorbent and reducing regeneration energy consumption while ensuring absorption capacity and absorption rate.
[0025] The beneficial effects of this invention are:
[0026] Compared with traditional alkanolamine solution absorption systems, this invention adopts a novel absorbent structure design strategy. By embedding quaternary carbon steric hindrance groups into the molecular backbone of aliphatic polyamines, it acquires the following superior properties: 1) It inhibits thermal and oxidative degradation processes, such as dealkylation, Hoffmann elimination, hydroxyl oxidation, and Cope elimination, thereby enhancing the stability of the absorbent. After being heated at 150°C for 120 hours in an air atmosphere within a closed system under saturated carbon dioxide absorption conditions, the absorbent's carbon dioxide absorption performance remains unchanged; 2) It utilizes steric hindrance groups to regulate the interaction strength between amine groups and carbon dioxide, improving the regeneration efficiency and reducing regeneration energy consumption while ensuring absorption capacity and absorption rate. Under 120°C conditions, the absorbent can achieve complete regeneration within 80 minutes, with a regeneration enthalpy in the range of 56–68 kJ / mol.
[0027] 100g of N with a mass fraction of 25% 1 Taking a solution of (2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine as an example, its advantages include:
[0028] (1)N 1 The carbon dioxide mass absorption of the (2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine solution was 13.8 wt% after 80 min at 40 °C and 0.1 MPa, and 10.9 wt% after 30 min.
[0029] (2)N 1 The solution of (2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine can be completely regenerated within 80 min at 120 °C, with a regeneration ratio of 88% at 30 min and a regeneration enthalpy of 59 kJ / mol.
[0030] (3)N 1 The carbon dioxide absorption performance of a solution of (2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine remains unchanged after heating at 150°C for 120 hours in a closed system under air atmosphere under saturated carbon dioxide absorption conditions. Detailed Implementation
[0031] The present invention will be further described in detail below with reference to the appendix and specific examples.
[0032] Example 1
[0033] N 1 Synthesis of 1,2-(2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine
[0034]
[0035] Bis(2-chloro-2-methylpropyl)amine hydrochloride (200 mmol, 48.71 g) and ammonia (25 wt%, 240 mL) were sequentially added to a 500 mL high-pressure reactor. The reactor was sealed and reacted in an oil bath at 80 °C for 12 h with magnetic stirring at 600 rpm. After the reaction, the reactor was immersed in an ice-water bath for 0.5 h. The reaction solution was then transferred to a 1 L wide-mouth flask cooled in an ice-water bath, and NaOH (80 g) was added in portions with magnetic stirring (800 rpm). After stirring for 30 min, the solution was transferred to a 500 mL separatory funnel. The lower aqueous phase was removed, and the upper aqueous organic phase was extracted with dichloromethane (120 mL × 2). The dichloromethane phases were combined and dried over anhydrous Na₂SO₄ for 12 h. After removing the dichloromethane solvent using a rotary evaporator, N₂ was obtained by vacuum distillation. 1-(2-amino-2-methylpropyl)-2-methylpropyl-1,2-diamine, yield 55%. NMR characterization data: 1 H NMR (400MHz, CDCl3) δ = 1.35 (s, 12H), 2.58 (s, 4H).
[0036] Example 2
[0037] N 2 2-Dimethyl-N 1 Synthesis of 1,2-propanediamine (2-methylamino-2-methylpropyl)
[0038]
[0039] Bis(2-chloro-2-methylpropyl)amine hydrochloride (200 mmol, 48.71 g) and methylamine solution (40 wt%, 200 mL) were sequentially added to a 500 mL high-pressure reactor. The reactor was sealed and reacted in an oil bath at 80 °C for 12 h with magnetic stirring at 600 rpm. After the reaction, the reactor was immersed in an ice-water bath for 0.5 h. The reaction solution was then transferred to a 1 L wide-mouth flask cooled in an ice-water bath, and NaOH (80 g) was added in portions with magnetic stirring (800 rpm). After stirring for 30 min, the solution was transferred to a 500 mL separatory funnel. The lower aqueous phase was removed, and the upper aqueous organic phase was extracted with dichloromethane (120 mL × 2). The dichloromethane phases were combined and dried over anhydrous Na₂SO₄ for 12 h. After removing the dichloromethane solvent using a rotary evaporator, N₂ was obtained by vacuum distillation. 2 2-Dimethyl-N 1 -(2-methylamino-2-methylpropyl)-1,2-propanediamine, yield 72%. NMR characterization data: 1 H NMR (400MHz, CDCl3) δ = 1.34 (s, 12H), 2.52 (s, 6H), 2.61 (s, 4H).
[0040] Example 3
[0041] N 1 -(3-Methylamino-2,2-dimethylpropyl)-N 3 Synthesis of 2,2-trimethylpropyl-1,3-diamine
[0042]
[0043] Bis(3-chloro-2,2-dimethylpropyl)amine hydrochloride (200 mmol, 52.53 g) and methylamine solution (40 wt%, 200 mL) were sequentially added to a 500 mL high-pressure reactor. The reactor was sealed and reacted in an oil bath at 80 °C for 12 h with magnetic stirring at 600 rpm. After the reaction, the reactor was immersed in an ice-water bath for 0.5 h. The reaction solution was then transferred to a 1 L wide-mouth flask cooled in an ice-water bath, and NaOH (80 g) was added in portions with magnetic stirring (800 rpm). After stirring for 30 min, the solution was transferred to a 500 mL separatory funnel. The lower aqueous phase was removed, and the upper aqueous organic phase was extracted with dichloromethane (120 mL × 2). The dichloromethane phases were combined and dried over anhydrous Na₂SO₄ for 12 h. After removing the dichloromethane solvent using a rotary evaporator, N₂ was obtained by vacuum distillation. 1 -(3-Methylamino-2,2-dimethylpropyl)-N 3 2,2-Trimethylpropyl-1,3-diamine, yield 85%. NMR characterization data: 1 H NMR (400MHz, CDCl3) δ = 1.02 (s, 12H), 2.36 (s, 4H), 2.38 (s, 4H), 3.17 (s, 6H).
[0044] Example 4
[0045] N 1 -(3-Methylamino-2,2-dimethylpropyl)-N 1 N 3 Synthesis of 2,2-Tetramethylpropyl-1,3-diamine
[0046]
[0047] Bis(3-chloro-2,2-dimethylpropyl)methylamine hydrochloride (200 mmol, 55.33 g) and methylamine solution (40 wt%, 200 mL) were sequentially added to a 500 mL high-pressure reactor. The reactor was sealed and reacted in an oil bath at 80 °C for 12 h with magnetic stirring at 600 rpm. After the reaction, the reactor was immersed in an ice-water bath for 0.5 h. The reaction solution was then transferred to a 1 L wide-mouth flask cooled in an ice-water bath, and NaOH (80 g) was added in portions with magnetic stirring (800 rpm). After stirring for 30 min, the solution was transferred to a 500 mL separatory funnel. The lower aqueous phase was removed, and the upper aqueous organic phase was extracted with dichloromethane (120 mL × 2). The dichloromethane phases were combined and dried over anhydrous Na₂SO₄ for 12 h. After removing the dichloromethane solvent using a rotary evaporator, N₂ was obtained by vacuum distillation. 1 -(3-Methylamino-2,2-dimethylpropyl)-N 1 N 32,2-Tetramethylpropyl-1,3-diamine, yield 89%. NMR characterization data: 1 HNMR (400MHz, CDCl3) δ = 1.01 (s, 12H), 2.06 (s, 3H), 2.19 (s, 4H), 2.35 (s, 4H), 3.21 (s, 6H).
[0048] Example 5
[0049] Add 25g of the sterically hindered fatty polyamine absorbent obtained in Examples 1-4 and 75g of deionized water to a 250mL round-bottom flask. After stirring evenly, slowly introduce a carbon dioxide-nitrogen mixture with a carbon dioxide volume content of 15%. The flow rate of the mixture is 100mL / min, the pressure is 0.1MPa, and the oil bath temperature is 40℃. Record the inlet and outlet flow rates in real time using a gas flow meter. The test results of the carbon dioxide absorption performance of the sterically hindered fatty polyamine absorbent solution are shown in Table 1.
[0050] Table 1. Carbon dioxide absorption performance of sterically hindered fatty polyamine absorbent solutions
[0051]
[0052] Example 6
[0053] Under magnetic stirring, 100g of the sterically hindered fatty polyamine absorbent solution saturated with carbon dioxide from Example 5 was placed in an oil bath, and the oil bath temperature was raised to 120°C. The inlet and outlet gas flow rates were recorded in real time using a gas flow meter. The regeneration performance test results of the sterically hindered fatty polyamine absorbent solution are shown in Table 2.
[0054] Table 2. Regeneration performance of sterically hindered fatty polyamine absorbent solutions
[0055]
[0056] Example 7
[0057] 100g of the sterically hindered fatty polyamine absorbent solution saturated with carbon dioxide from Example 5 was added to a 500mL high-pressure reactor. After sealing in air, the reactor was heated in a 150℃ oil bath for 120h. The reactor was then immersed in an ice-water bath for 1h. The absorbent solution was transferred to a 250mL round-bottom flask, and nitrogen gas was slowly introduced for 30min with magnetic stirring at a flow rate of 100mL / min, a pressure of 0.1MPa, and an oil bath temperature of 40℃. After purging residual carbon dioxide, a carbon dioxide-nitrogen mixture with a volume content of 15% was slowly introduced with magnetic stirring at a flow rate of 100mL / min, a pressure of 0.1MPa, and an oil bath temperature of 40℃. The inlet and outlet flow rates were recorded in real time using a gas flow meter. After stability testing, the carbon dioxide absorption capacity of the sterically hindered fatty polyamine absorbent solution did not change significantly, demonstrating good resistance to thermal and oxidative degradation.
[0058] The examples above are merely some specific embodiments of the present invention. Obviously, the embodiments described in this invention can have many variations; therefore, all variations derived directly or indirectly by those skilled in the art from the disclosure of this invention should be considered within the scope of protection of this invention.
Claims
1. A type of sterically hindered fatty polyamine solution for capturing carbon dioxide, characterized in that: By weight, it includes 20-40 parts of sterically hindered fatty polyamine as an absorbent and 60-80 parts of water, wherein the sterically hindered fatty polyamine is one or more of the compounds shown in formula (I) and formula (II). Equation (I) Equation (II) Among them, R 1 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl; R 2 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl; R 3 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl; R 4 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl; R 5 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl; R 6 It can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or 2-hydroxyethyl.
2. The sterically hindered fatty polyamine solution according to claim 1, characterized in that: The preparation method of the sterically hindered fatty polyamine includes the following steps: S1. Bis(2-chloro-2-methylpropyl)amine hydrochloride, bis(2-chloro-2-methylpropyl)methylamine hydrochloride, bis(3-chloro-2,2-dimethylpropyl)amine hydrochloride, or bis(3-chloro-2,2-dimethylpropyl)methylamine hydrochloride, designated as component 1, and ammonia, methylamine solution, ethylamine solution, n-propylamine, isopropylamine, n-butylamine, isobutylamine, or 2-aminoethanol, designated as component 2, are sequentially added to a high-pressure reactor and heated to 60-90°C. o The reaction is carried out at C for 8-14 h; the molar ratio of the effective reactants of component 1 and component 2 is 1:4-40; After soaking the high-pressure reactor in an ice-water bath for 0.5-1 h, the reaction mixture is transferred to a wide-mouth bottle cooled in an ice-water bath. NaOH is added in batches with stirring. The molar ratio of NaOH to component 1 is 4-16:1, and the stirring time is 10-40 min. Then, the entire mixture is transferred to a separatory funnel and allowed to stand. The lower aqueous phase is released, and the upper aqueous organic phase is collected. S3 extracts the upper aqueous organic phase with dichloromethane. After combining the dichloromethane phases, the mixture is dried with anhydrous Na2SO4 for 8-14 h. The dichloromethane solvent is removed by rotary evaporation, and then the mixture is distilled under reduced pressure to obtain one of the compounds shown in formula (I) and formula (II).
3. The application of a sterically hindered fatty polyamine solution according to any one of claims 1-2 in carbon dioxide capture, characterized in that: This sterically hindered fatty polyamine solution is used for the decarbonization treatment of industrial waste gas or energy gas containing carbon dioxide.
4. The application according to claim 3, characterized in that, Industrial waste gas or energy gas containing carbon dioxide comes from power plant flue gas, oil refinery tail gas, steel plant tail gas, cement plant tail gas, chemical plant tail gas, water gas, biogas, natural gas, or carbonate ore decomposition gas.
5. The application according to claim 3, characterized in that: The operating conditions for sterically hindered fatty polyamine solutions are: gas pressure of 0.1~0.5 MPa, carbon dioxide concentration of 5%~80%, and absorption temperature of 20.0~60.0 °C. o C, absorption time is 0.1~0.8 h, regeneration temperature is 80~130℃ o C, the regeneration time is 0.1~0.8 h.