Carbon dioxide capturing agent and use thereof

Abstract

The application discloses a carbon dioxide capturing agent and application thereof, and the carbon dioxide capturing agent contains a compound as shown in the formula (I): in the formula (I), the substituent groups R1 and R2 are each independently selected from hydrogen, an alkyl group, a hydroxyl group or an alkoxy group, the substituent groups R3, R4, R5 and R6 are each independently selected from a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group or an i-butyl group, and n1 and n2 are integers from 1 to 4. The tertiary amine disclosed in the application has a carbon dioxide absorption effect which is obviously superior to that of the known N-methyldiethanolamine, N,N,N',N'-tetraethylmethylenediamine and N,N-diethylethanolamine and other commonly used tertiary amine carbon dioxide capturing agents.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide capture technology, specifically relating to a carbon dioxide capture agent and its application. Background Technology

[0002] The depletion of fossil resources (mainly coal, oil, and natural gas) has led to excessive emissions of the greenhouse gas carbon dioxide, which accumulates in the atmosphere and exacerbates the greenhouse effect. Currently, carbon dioxide capture methods mainly include chemical, physical, and physicochemical methods. Among these, the chemical method using amine solutions to capture carbon dioxide is a relatively mature technology. However, due to differences in molecular structure, including different electron-donating amino groups (primary amine RNH2, secondary amine R2NH, and tertiary amine R3N), chain lengths, and substituent types, the carbon dioxide capture performance of different amines varies. Based on the reaction mechanism between amines of different structural types and carbon dioxide, each equivalent of primary and secondary amines absorbs 0.5 equivalents of carbon dioxide, while each equivalent of tertiary amine can absorb 1 equivalent of carbon dioxide. Therefore, tertiary amines have the best capture effect and are currently the focus of carbon dioxide capture agent screening. Currently, the most commonly used tertiary amine carbon dioxide capture agent is N-methyldiethanolamine, which can absorb 45g of carbon dioxide per 1L of 30% aqueous solution (J. Chem. Eng. Data, 1992, 37, 100-104). In recent years, the literature has also reported some tertiary amine structures with better carbon dioxide capture performance than N-methyldiethanolamine. For example, in 2009, FAChowdhury et al. screened N,N,N',N'-tetraethylmethyldiamine through absorption experiments, which could absorb 114g of carbon dioxide per 1L of 30% aqueous solution (EnergyProcedia, 2009, 1, 1241-1248). In 2017, N. El Hadri et al. screened N,N-diethylethanolamine, which could absorb 96g of carbon dioxide per 1L of 30% aqueous solution (Applied Energy, 2017, 185, 1433-1449). As mentioned above, some progress has been made in the screening of carbon dioxide capture agents; however, researchers are still dedicated to screening or preparing carbon dioxide capture agents with even better absorption performance. Summary of the Invention

[0003] To address the above problems, the present invention aims to provide a carbon dioxide capture agent and its application.

[0004] The specific technical solution is as follows:

[0005] A carbon dioxide trap containing a compound as shown in formula (I):

[0006]

[0007] In formula (I), substituents R1 and R2 are each independently selected from hydrogen, alkyl, hydroxyl or alkoxy, preferably hydrogen, alkoxy or hydroxyl, more preferably hydrogen, hydroxyl or methoxy, substituents R3, R4, R5 and R6 are each independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl, preferably methyl or ethyl, n1 and n2 are integers from 1 to 4, preferably n1 and n2 are 1 or 2.

[0008] An application of the above-mentioned carbon dioxide capture agent is characterized by comprising the following steps: mixing a bromosubstituted amine as shown in formula (II) and formula (III) with an amine as shown in formula (IV), adding ethanol and N,N-diisopropylethylamine, stirring the reaction at a specific temperature and reaction time, monitoring the reaction by TLC until the reaction is completed, and separating and purifying the reaction solution to obtain a tertiary amine carbon dioxide capture agent as shown in formula (I). The reaction process is as follows:

[0009]

[0010] Furthermore, the molar ratio of the amines in formulas (II), (III), and (IV) is as follows:

[0011] 1:1:10.0~100.0, preferably 1:1:20.0~80.0.

[0012] Furthermore, the molar ratio of the solvent ethanol to the substance of formula (II) is 50.0 to 200.0:1, preferably 100.0 to 150.0:1; the molar ratio of the solvent N,N-diisopropylethylamine to the substance of formula (II) is 1.0 to 8.0:1, preferably 2.0 to 5.0:1.

[0013] Furthermore, the reaction temperature is 25–120°C, preferably 40–80°C; the stirring reaction time is 10–30 hours, preferably 15–22 hours.

[0014] An application of a carbon dioxide trapping agent, wherein the application is the use of the carbon dioxide trapping agent in carbon dioxide capture.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The tertiary amine described in this invention has a significantly better carbon dioxide absorption effect than commonly used tertiary amine carbon dioxide capture agents such as N-methyldiethanolamine, N,N,N',N'-tetraethylmethyldiamine, and N,N-diethylethanolamine. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0018] Example 1 Synthesis of tertiary amine Ia (R1=OH, R2=H, R3, R4, R5, R6=methyl, n1, n2=1) 2-bromo-N,N-dimethylethane-1-amine (1 mmol), 3-amino-1-propanol (30 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.4 mmol) were weighed into a 25 mL flask and stirred at 65 °C. The reaction was monitored by TLC. After 18 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fraction collected at 77–79 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product 3-(bis(2-(dimethylamino)ethyl)amino)prop-1-ol) in a yield of 78%.

[0019] The compound 1 H NMR and HRMS (ESI) are as follows: 1 H NMR(400MHz, CDCl3)δ3.52(d,J=5.0Hz,2H),2.68(s,4H),2.62-2.47(m,6H),2.32(s,12H),1.94(s,2H).HRMS(ESI)calcd C 11 H 27 O1N3[M+H] + 217.0965, found 217.0954.

[0020] Example 2 Synthesis of tertiary amine Ib (R1 = methoxy, R2 = H, R3, R4, R5, R6 = methyl, n1, n2 = 1)

[0021] 2-Bromo-N,N-dimethylethane-1-amine (1 mmol), 3-methoxy-1-propanamine (20 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.0 mmol) were weighed into a 25 mL flask and stirred at 40 °C. The reaction was monitored by TLC. After 22 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fraction at 67–69 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product N. 1 -(2-(dimethylamino)ethyl)-N 1 -(3-Methoxypropyl)-N 2 N 2 -Dimethylethane-1,2-diamine, yield 65%.

[0022] The compound 1 H NMR and HRMS (ESI) are as follows: 1H NMR(400MHz, CDCl3)δ3.42(s,2H),3.27(s,3H),2.69(s,4H),2.58-2.45(m,6H),2.30(s,12H),1.96(s,2H).HRMS(ESI)calcdC 12 H 29 O1N3[M+H] + 231.0523, found 231.0514.

[0023] Example 3 Synthesis of tertiary amine Ic (R1 = methoxy, R2 = H, R3, R4, R5, R6 = ethyl, n1, n2 = 1)

[0024] 2-Bromo-N,N-diethylethane-1-amine (1 mmol), 3-methoxy-1-propanamine (20 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.0 mmol) were weighed into a 25 mL flask and stirred at 40 °C. The reaction was monitored by TLC. After 22 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fraction at 75–77 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product N. 1 -(2-(diethylamino)ethyl)-N 2 N 2 -Diethyl-N 1 -(3-methoxypropyl)ethane-1,2-diamine, yield 62%.

[0025] The compound 1 H NMR and HRMS (ESI) are as follows: 1 H NMR(400MHz, CDCl3)δ3.42(s,2H),3.24(s,3H),2.63-2.50(m,18H),2.01(s,2H),0.99(s,12H).HRMS(ESI)calcd C 16 H 37 O1N3[M+H] + 287.0624, found 287.0612.

[0026] Example 4 Synthesis of tertiary amine Id (R1, R2 = OH, R3, R4, R5, R6 = methyl, n1, n2 = 1)

[0027] 2-Bromo-N,N-dimethylethane-1-amine (1 mmol), 3-amino-1,2-propanediol (30 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.4 mmol) were weighed into a 25 mL flask and stirred at 80 °C. The reaction was monitored by TLC. After 15 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fraction at 112–114 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product 3-(bis(2-(dimethylamino)ethyl)amino)propane-1,2-diol, with a yield of 73%.

[0028] The compound 1 H NMR and HRMS (ESI) are as follows: 1 H NMR (400MHz, CDCl3) δ3.79-3.61(m,3H),3.53(d,J=12.5Hz,1H),3.02(d,J=12.4Hz,1H),2 .73(d,J=12.4Hz,2H),2.63(d,J=12.3Hz,2H),2.54(s,4H),2.29(s,12H).HRMS(ESI)calcd C 11 H 27 O2N3[M+H] + 233.0165, found 233.0152.

[0029] Example 5 Synthesis of tertiary amine Ie (R1, R2 = OH, R3, R5, R4, R6 = ethyl, n1, n2 = 1)

[0030] 2-Bromo-N,N-diethylethane-1-amine (1 mmol), 3-amino-1,2-propanediol (80 mmol), ethanol (150 mmol), and N,N-diisopropylethylamine (5 mmol) were weighed into a 25 mL flask and stirred at 65 °C. The reaction was monitored by TLC. After 18 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fractions at 116–119 °C / 133.3 Pa were collected by vacuum distillation to obtain the target product 3-(bis(2-(diethylamino)ethyl)amino)propane-1,2-diol) in a yield of 55%.

[0031] The compound 1 H NMR and HRMS (ESI) are as follows: 1 H NMR(400MHz, CDCl3)δ3.79-3.63(m,3H),3.24-2.67(dd,2H),2.64-2.53(m,16H),0.99(s,12H).HRMS(ESI)calcdC 15 H 35O2N3[M+H] + 288.9594, found 288.9582.

[0032] Example 6 Synthesis of tertiary amine If (R1, R2 = OH, R3, R4, R5, R6 = methyl, n1, n2 = 2)

[0033] 3-Bromo-N,N-dimethyl-1-propanediol (1 mmol), 3-amino-1,2-propanediol (30 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.4 mmol) were weighed into a 25 mL flask and stirred at 65 °C. The reaction was monitored by TLC. After 18 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fraction at 129–131 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product 3-(bis(3-(dimethylamino)propyl)amino)propane-1,2-diol, with a yield of 70%.

[0034] The compound 1 H NMR and HRMS (ESI) are as follows: 1 H NMR(400MHz, CDCl3) δ3.89(dd,J=12.4,5.5Hz,1H),3.82-3.67(m,2H),2.86-2.72(m,2 H),2.69-2.52(m,4H),2.46(s,4H),2.31-2.28(s,12H),1.75(s,4H).HRMS(ESI)calcd C 13 H 31 O2N3[M+H] + 261.0364, found 261.0352.

[0035] Example 7 Synthesis of tertiary amine Ig (R1, R2 = OH, R3, R4, R5, R6 = ethyl, n1, n2 = 2)

[0036] 3-Bromo-N,N-diethyl-1-propanediol (1 mmol), 3-amino-1,2-propanediol (30 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.4 mmol) were weighed into a 25 mL flask and stirred at 65 °C. The reaction was monitored by TLC. After 18 h, the reaction was completed. The solvent was removed by concentration of the reaction solution, and the fraction at 135–137 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product 3-(bis(3-(diethylamino)propyl)amino)propane-1,2-diol, with a yield of 64%.

[0037] The compound 1 H NMR and HRMS (ESI) are as follows:1 H NMR (400MHz, CDCl3) δ3.82-3.61(m,3H),3.05(d,J=12.3Hz,2H),2.61-2.53(m,8H),2. 46-2.51(m,4H),2.45-2.36(m,4H),1.91-1.77(m,4H),1.00(s,12H).HRMS(ESI)calcd C 17 H 39 O2N3[M+H] + 317.0466, found 317.0457.

[0038] Example 8 Synthesis of tertiary amine Ih (R1 = OH, R2 = H, R3, R4 = methyl, R5, R6 = ethyl, n1, n2 = 1)

[0039] 2-Bromo-N,N-dimethylethane-1-amine (1 mmol), 2-bromo-N,N-diethylethane-1-amine (1 mmol), 3-amino-1-propanol (30 mmol), ethanol (100 mmol), and N,N-diisopropylethylamine (2.4 mmol) were weighed into a 25 mL flask and stirred at 65 °C. The reaction was monitored by TLC. After 18 h, the reaction was completed. The reaction solution was concentrated to remove the solvent, and the fraction at 78–80 °C / 133.3 Pa was collected by vacuum distillation to obtain the target product 3-(2-(diethylamino)ethyl)(2-(dimethylamino)ethyl)amino)prop-1-ol, with a yield of 53%.

[0040] The compound 1 H NMR and HRMS (ESI) are as follows: 1 H NMR (400MHz, CDCl3) δ3.53(d,J=5.1Hz,2H),2.68(d,J=6.9Hz,4H),2.60-2.58(d,J=9.8Hz ,6H),2.50-2.48(d,J=8.5Hz,4H),2.30(s,6H),1.92(s,2H),0.99(s,6H).HRMS(ESI)calcd C 13 H 31 O1N3[M+H] + 245.0256, found245.0245.

[0041] Example 9: Testing of Carbon Dioxide Capture Performance

[0042] The carbon dioxide capture performance of the tertiary amine compounds synthesized in Examples 1–8 was tested experimentally. The test concentrations were 1.0 mol / L, 3.0 mol / L, and 5.0 mol / L, respectively. The aforementioned tertiary amines with good carbon dioxide absorption capacity reported in the literature—N,N,N',N'-tetraethylmethyldiamine, N,N-diethylethanolamine, and N-methyldiethanolamine—were used as controls.

[0043] The specific experimental procedure is as follows: First, the tertiary amine is mixed with water to prepare an amine solution of the required concentration in 100 mL. A mixture of 20% carbon dioxide and 80% nitrogen gas is bubbled into a water saturator, and then bubbled into the prepared amine solution for carbon dioxide absorption. After a period of time, the weight difference before and after absorption is measured, and the carbon dioxide loading is calculated and recorded using the following formula.

[0044]

[0045] The test results are shown in Table 1.

[0046] Table 1. Absorption performance of tertiary amine compounds for carbon dioxide in different examples at different concentrations.

[0047]

[0048]

[0049] As shown in Table 1, the tertiary amines presented in the embodiments of this invention exhibited good carbon dioxide absorption capacity at all tested concentrations, with significantly better carbon dioxide absorption rates than the tertiary amines shown in control groups 1, 2, and 3. The results in the table indicate that tertiary amines at different concentrations have different carbon dioxide absorption capacities, with the carbon dioxide absorption capacity at a concentration of 3.0 mol / L being superior to that at 1.0 mol / L and 5.0 mol / L concentrations. At a concentration of 3.0 mol / L, the carbon dioxide saturation loading of tertiary amines Id and Ie was higher than that at 2.80 mol CO2 / mol amine. In summary, the tertiary amine compounds presented in this invention are highly efficient carbon dioxide traps.

[0050] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A carbon dioxide trap, characterized in that, It contains compounds as shown in formula (I): ， In formula (I), substituents R1 and R2 are each independently selected from hydroxyl or methoxy, substituents R3, R4, R5, and R6 are each independently selected from methyl or ethyl, and n1 and n2 are 1 or 2.

2. The application of the carbon dioxide trap as described in claim 1, characterized in that, The application described is the use of carbon dioxide trapping agents in carbon dioxide capture.

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