Seven-membered cyclic organic polyamine, preparation method and application

Abstract

The invention provides seven-membered cyclic organic polyamine as well as a preparation method and application thereof, and relates to the technical field of carbon dioxide capture. The seven-membered cyclic organic polyamine provided by the invention can reversibly convert carbon dioxide into bicarbonate which is easy to decompose while keeping a relatively high thermodynamic driving force in an absorption process by utilizing a synergistic effect of compounding an external steric hindrance primary amine and an internal secondary amine / tertiary amine, so that the desorption rate is increased and the desorption energy consumption is reduced. The seven-membered cyclic organic polyamine absorbent provided by the invention is composed of seven-membered cyclic organic polyamine and water, and has the advantages of high carbon dioxide absorption capacity and rapid desorption.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and particularly relates to a heptacyclic organic polyamine absorbent, a preparation method and an application thereof. Background Art

[0002] Carbon dioxide is the greenhouse gas with the largest emissions and is one of the main causes of climate change represented by global warming. Carbon capture, utilization and storage technology (CCUS) is the most effective countermeasure to deal with excessive industrial carbon dioxide emissions at present. A rapid, high-capacity, low-energy-consuming and low-loss carbon capture process constitutes the material basis of CCUS technology and is also the fundamental prerequisite for determining the development and implementation of CCUS technology.

[0003] The chemical absorption method of carbon dioxide relying on amine solutions (Reaction Formula 1) is the most mature and widely used carbon capture strategy in the industrial field at present. It has the advantages of rapid response, high carbon dioxide selectivity, simple equipment and low amine solution cost. Many domestic and foreign related enterprises have completed multiple demonstration devices. However, due to the limitations of the structure of amine absorbents themselves, the reaction of their amino groups with carbon dioxide mostly generates carbamates with strong thermal stability, resulting in problems such as slow desorption rate and high desorption energy consumption. In addition, the amino group content of amine compounds is also relatively low, and most molecules contain only one active amino group, which also limits their carbon dioxide cyclic capture capacity in actual production.

[0004] Reaction Formula 1:

[0005]

[0006] The above-mentioned essential disadvantages at the molecular level have become bottlenecks that are difficult to overcome in the further optimization and development of amine-based carbon dioxide chemical absorbents. Therefore, the academic and industrial circles urgently need to design and develop a new chemical absorption system with higher desorption efficiency in order to fundamentally solve the deficiencies in the reactivity of amine molecules. Summary of the Invention

[0007] The purpose of the present invention is to provide a heptacyclic organic polyamine absorbent, a preparation method and an application thereof. The heptacyclic organic polyamine absorbent provided by the present invention has the advantages of high carbon dioxide absorption capacity and rapid desorption.

[0008] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0009] The present invention provides a heptacyclic organic polyamine having the structure shown in Formula I:

[0010]

[0011] In Formula I, R 1 、R2 and R 3 is H or a C1-C3 alkyl group.

[0012] Furthermore, it has the structure shown in any one of Formulas I-1 to I-12:

[0013]

[0014] The present invention provides a method for preparing the seven-membered cyclic organic polyamine described in the above solution, comprising the following steps:

[0015] Mix compound 1 and compound 2 in an organic solvent, carry out a cyclization reaction, and then add a transition metal catalyst to the reaction mixture and introduce hydrogen gas to carry out a pressurized hydrogenation reaction to obtain the seven-membered cyclic organic polyamine;

[0016]

[0017] In the said compound 1, R 1 is H or a C1-C3 alkyl group;

[0018] In the said compound 2, R 2 and R 3 are H or a C1-C3 alkyl group.

[0019] Furthermore, in the present invention, it is preferred to first dissolve compound 1 in an organic solvent, then add compound 2 and the organic solvent in which compound 1 is dissolved to a high-pressure reaction kettle, seal the reaction kettle and carry out a heating cyclization reaction. After the reaction is completed and the temperature is lowered, open the reaction kettle to add a transition metal catalyst, seal the reaction kettle again and purge the air in the kettle with nitrogen, and then introduce hydrogen gas after the purging is completed to carry out a pressurized heating hydrogenation reaction.

[0020] Furthermore, in the present invention, both the heating cyclization reaction and the pressurized heating hydrogenation reaction are preferably carried out under stirring conditions. The present invention has no special requirements for the stirring rate, and specifically it is 500 r / min in the examples of the present invention.

[0021] Furthermore, after completing the pressurized heating hydrogenation reaction, the present invention preferably cools the obtained reaction stock solution and filters it, washes the filter cake with an organic solvent, combines the washing liquid and the filtrate, removes the solvent completely using a rotary evaporator, and performs vacuum distillation to obtain the seven-membered cyclic organic polyamine.

[0022] Furthermore, the molar ratio of compound 1 to compound 2 is 1:(0.1-10), preferably 1:(0.5-5), and more preferably 1:(0.8-2).

[0023] Furthermore, the transition metal catalyst is a nickel-based catalyst or a palladium-based catalyst. The nickel-based catalyst is preferably Raney nickel or nickel powder; the palladium-based catalyst is preferably palladium on carbon, palladium-aluminum oxide or palladium-silica. The mass of the transition metal catalyst is 0.01-20% of the total mass of Compound 1 and Compound 2, preferably 1-15%, more preferably 2-10%.

[0024] Furthermore, the organic solvent is one or a mixture of two or more of methanol, ethanol, isopropanol, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, and ethyl acetate. There is no special requirement for the dosage of the organic solvent in the present invention, as long as it can dissolve the raw materials.

[0025] Furthermore, the temperature of the heating cyclization reaction is 20-80°C, preferably 20-60°C, more preferably 30-50°C; the time of the heating cyclization reaction is 1-24 h, preferably 5-18 h, more preferably 8-16 h.

[0026] Furthermore, the temperature of the pressurized heating hydrogenation reaction is 20-120°C, preferably 20-80°C, more preferably 30-60°C; the time of the pressurized heating hydrogenation reaction is 1-48 h, preferably 6-36 h, more preferably 10-20 h; the hydrogen pressure is 0.1-10 MPa, preferably 1-5 MPa.

[0027] The present invention provides the use of the seven-membered cyclic organic polyamine described in the above solution or the seven-membered cyclic organic polyamine prepared by the preparation method described in the above solution as an absorbent in the absorption of carbon dioxide.

[0028] Furthermore, when the seven-membered cyclic organic polyamine absorbent of the present invention is used to absorb carbon dioxide, the volume concentration of carbon dioxide is preferably 1-80%, the pressure of the mixed gas stream is preferably 0.05-4 MPa; the absorption temperature is preferably 20-80°C, and the absorbent regeneration temperature is preferably 70-120°C.

[0029] Furthermore, the present invention has no special requirement for the source of the carbon dioxide, and any well-known source in the art can be used, such as power plant flue gas, refinery tail gas, steel mill tail gas, cement plant tail gas, petrochemical plant tail gas, water gas, biogas, natural gas or carbonate ore decomposition gas. The present invention can achieve the purpose of capturing carbon dioxide or removing carbon dioxide from the carbon dioxide-containing mixed gas stream by absorbing carbon dioxide.

[0030] The present invention provides a heptacyclic organic polyamine absorbent, which, by mass percentage, comprises 1-50% (specifically, it can be 10%, 15%, 20%, 25%, 30%, 40%, 50%, not enumerated here one by one) of the heptacyclic organic polyamine described in the above solution or the heptacyclic organic polyamine prepared by the preparation method described in the above solution, and 50-99% of water. In the embodiments of the present invention, the heptacyclic organic polyamine absorbent is composed of 30 wt% of the heptacyclic organic polyamine and 70 wt% of water.

[0031] Furthermore, the present invention has no special requirements for the preparation method of the heptacyclic organic polyamine absorbent, and it can be directly prepared by uniformly mixing the heptacyclic organic polyamine and water.

[0032] The heptacyclic organic polyamine provided by the present invention utilizes the synergistic effect of the combination of exocyclic sterically hindered primary amines and endocyclic secondary / tertiary amines. During the absorption process, while maintaining a relatively high thermodynamic driving force, it reversibly converts carbon dioxide into bicarbonate that is easy to decompose, thereby increasing the desorption rate and reducing the desorption energy consumption.

[0033] The present invention provides a preparation method of the heptacyclic organic polyamine described in the above technical solution. The preparation method provided by the present invention uses commercial reaction raw materials, has few operation steps, and a simple production process, and is suitable for large-scale industrial synthesis.

[0034] The present invention provides a heptacyclic organic polyamine absorbent, which comprises the above-mentioned heptacyclic organic polyamine and water. Compared with the traditional alkanolamine absorption method, the present invention conducts targeted design and optimization of the absorbent structure at the molecular level, and has the following excellent properties: realizing the polyamine group synergistic effect by introducing the combination of exocyclic sterically hindered primary amines and endocyclic secondary / tertiary amines, that is, regulating the reaction path during the carbon dioxide absorption process to generate bicarbonate that is easier to decompose and has a higher carbon dioxide mass content. As shown by the test results of the examples, under the conditions of 40 °C and 0.1 MPa, the carbon dioxide absorption capacity of the absorbent provided by the present invention can reach up to 1.78 mol CO2 / mol absorbent within 50 minutes, and the desorption rate is 0.030 mol CO2 / mol / min. This shows that the absorbent provided by the present invention has a high absorption capacity and rapid desorption. Specific Embodiments

[0035] The following combines examples to elaborate in detail on the heptacyclic organic polyamine absorbent provided by the present invention, its preparation method and application, but they cannot be construed as limiting the protection scope of the present invention.

[0036] Example 1

[0037] Synthesis of 1,4-diazepan-6-amine I-1

[0038]

[0039] 2-Nitropropanediol (100 mmol, 12.11 g), ethylenediamine (100 mmol, 6.01 g) and methanol (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 50 °C for 12 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reactor was opened and 1 g of 20 wt% palladium-carbon was added. After sealing again, nitrogen was introduced to displace air, and finally hydrogen (3 MPa) was introduced. The high-pressure reactor was reacted at 40 °C for 12 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reaction solution was filtered, and the filter cake was washed with methanol (30 mL × 2). After the washing solution and the filtrate were combined, the solvent methanol was removed completely by a rotary evaporator, and 1,4-diazacycloheptan-6-amine was obtained by vacuum distillation. NMR characterization data: 1 H NMR (400 MHz, CDCl3) δ = 2.90 - 2.81 (m, 4H), 2.73 (d, 2H), 2.68 (d, 2H), 2.53 (m, 1H), which is consistent with the target product.

[0040] Example 2

[0041] Synthesis of 6-Methyl-1,4-diazacycloheptan-6-amine I-2

[0042]

[0043] 2-Nitro-2-methyl-propanediol (100 mmol, 13.51 g), ethylenediamine (100 mmol, 6.01 g) and ethanol (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 60 °C for 10 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reactor was opened and 2 g of Raney nickel was added. After sealing again, nitrogen was introduced to displace air, and finally hydrogen (4 MPa) was introduced. The high-pressure reactor was reacted at 50 °C for 16 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reaction solution was filtered, and the filter cake was washed with ethanol (30 mL × 2). After the washing solution and the filtrate were combined, the solvent ethanol was removed completely by a rotary evaporator, and 6-methyl-1,4-diazacycloheptan-6-amine was obtained by vacuum distillation. NMR characterization data: 1 H NMR (400 MHz, CDCl3) δ = 2.92 - 2.86 (m, 2H), 2.82 - 2.76 (m, 2H), 2.71 (d, 2H), 2.55 (d, 2H), 1.32 (s, 3H), which is consistent with the target product.

[0044] Example 3

[0045] Synthesis of 6-ethyl-1,4-diazepan-6-amine I-3

[0046]

[0047] 2-Nitro-2-ethyl-1,3-propanediol (100 mmol, 14.92 g), ethylenediamine (100 mmol, 6.01 g) and tetrahydrofuran (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 50 °C for 14 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Subsequently, the reactor was opened and 1.5 g of Raney nickel was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (5 MPa) was introduced. The high-pressure reactor was reacted at 50 °C for 14 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Subsequently, the reaction solution was filtered, and the filter cake was washed with tetrahydrofuran (30 mL × 2). After the washing solution and the filtrate were combined, the solvent tetrahydrofuran was removed completely using a rotary evaporator, and 6-ethyl-1,4-diazepan-6-amine was obtained by vacuum distillation. NMR characterization data: 1 H NMR (400 MHz, CDCl3) δ = 2.94 - 2.88 (m, 2H), 2.84 - 2.78 (m, 2H), 2.71 (d, 2H), 2.59 (d, 2H), 1.35 (q, 2H), 0.87 (t, 3H), which is consistent with the target product.

[0048] Example 4

[0049] Synthesis of 6-propyl-1,4-diazepan-6-amine I-4

[0050]

[0051] 2-Nitro-2-propyl-propanediol (100 mmol, 16.32 g), ethylenediamine (100 mmol, 6.01 g) and ethylene glycol dimethyl ether (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 55 °C for 15 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reactor was opened and 3.5 g of Raney nickel was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (4.5 MPa) was introduced. The high-pressure reactor was reacted at 65 °C for 22 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reaction solution was filtered, and the filter cake was washed with ethylene glycol dimethyl ether (30 mL × 2). After the washing solution and the filtrate were combined, the solvent ethylene glycol dimethyl ether was removed completely by a rotary evaporator, and 6-propyl-1,4-diazepan-6-amine was obtained by vacuum distillation. NMR characterization data: 1 H NMR (400 MHz, CDCl3) δ = 2.93 - 2.86 (m, 2H), 2.85 - 2.75 (m, 2H), 2.73 (d, 2H), 2.61 (d, 2H), 1.42 (t, 2H), 1.30 (m, 2H), 0.85 (t, 3H), which is consistent with the target product.

[0052] Example 5

[0053] Synthesis of 1,4,6-Trimethyl-1,4-diazepan-6-amine I-5

[0054]

[0055] 2-Nitro-2-methyl-propanediol (100 mmol, 13.51 g), dimethylethylenediamine (100 mmol, 8.82 g) and dioxane (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 60 °C for 12 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reactor was opened and 2 g of nickel powder was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (5 MPa) was introduced. The high-pressure reactor was reacted at 50 °C for 20 h with a magnetic stirring speed of 500 r / min. After the reaction, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Then, the reaction solution was filtered, and the filter cake was washed with dioxane (30 mL × 2). After the washing solution and the filtrate were combined, the solvent dioxane was removed completely by a rotary evaporator, and 1,4,6-trimethyl-1,4-diazepan-6-amine was obtained by vacuum distillation. NMR characterization data: 11H NMR (400 MHz, CDCl3) δ = 2.90 - 2.85 (m, 2H), 2.81 - 2.74 (m, 2H), 2.69 (d, 2H), 2.51 (d, 2H), 2.31 (s, 6H), 1.33 (s, 3H), which is consistent with the target product.

[0056] Example 6

[0057] Synthesis of 1,4 - diethyl - 6 - methyl - 1,4 - diazaheptan - 6 - amine I - 6

[0058]

[0059] 2 - Nitro - 2 - methyl - propanediol (100 mmol, 13.51 g), diethyl ethylenediamine (100 mmol, 11.62 g) and methanol (100 mL) were successively added to a 300 mL high - pressure reactor. After sealing, the reaction was carried out at 70 °C for 16 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high - pressure reactor was immersed in an ice - water bath for 0.5 h. Then, the reactor was opened and 2.5 g of 10 wt% palladium on alumina was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (4 MPa) was introduced. The high - pressure reactor was reacted at 60 °C for 24 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high - pressure reactor was immersed in an ice - water bath for 0.5 h. Then, the reaction solution was filtered, and the filter cake was washed with methanol (30 mL × 2). After the washing solution and the filtrate were combined, the solvent methanol was removed completely using a rotary evaporator, and 1,4 - diethyl - 6 - methyl - 1,4 - diazaheptan - 6 - amine was obtained by vacuum distillation. NMR characterization data: 1 1H NMR (400 MHz, CDCl3) δ = 2.96 (q, 4H), 2.91 - 2.86 (m, 2H), 2.83 - 2.78 (m, 2H), 2.66 (d, 2H), 2.55 (d, 2H), 1.35 (s, 3H), 1.16 (t, 6H), which is consistent with the target product.

[0060] Example 7

[0061] Synthesis of 1,4 - diisopropyl - 6 - methyl - 1,4 - diazaheptan - 6 - amine I - 8

[0062]

[0063] 2-Nitro-2-methyl-1,3-propanediol (100 mmol, 13.51 g), diisopropylethylenediamine (100 mmol, 14.43 g) and methanol (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 80 °C for 24 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Subsequently, the reactor was opened and 2 g of 20 wt% palladium on carbon was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (3 MPa) was introduced. The high-pressure reactor was reacted at 80 °C for 24 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Subsequently, the reaction solution was filtered, and the filter cake was washed with methanol (30 mL × 2). After the washing solution and the filtrate were combined, the solvent methanol was removed completely using a rotary evaporator, and 1,4-diisopropyl-6-methyl-1,4-diazepan-6-amine was obtained by vacuum distillation. NMR characterization data: 1 1H NMR (400 MHz, CDCl3) δ = 2.94 - 2.88 (m, 2H), 2.84 - 2.78 (m, 2H), 2.76 (m, 2H), 2.68 (d, 2H), 2.52 (d, 2H), 1.34 (s, 3H), 1.08 (d, 12H), which is consistent with the target product.

[0064] Example 8

[0065] Synthesis of 1,6-dimethyl-1,4-diazepan-6-amine I-9

[0066]

[0067] 2-Nitro-2-methyl-1,3-propanediol (100 mmol, 13.51 g), methylethylenediamine (100 mmol, 7.41 g) and dioxane (100 mL) were successively added to a 300 mL high-pressure reactor. After sealing, the reaction was carried out at 30 °C for 10 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Subsequently, the reactor was opened and 1.5 g of Raney nickel was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (3 MPa) was introduced. The high-pressure reactor was reacted at 30 °C for 16 h with a magnetic stirring speed of 500 r / min. After the reaction was completed, the high-pressure reactor was immersed in an ice-water bath for 0.5 h. Subsequently, the reaction solution was filtered, and the filter cake was washed with dioxane (30 mL × 2). After the washing solution and the filtrate were combined, the solvent dioxane was removed completely using a rotary evaporator, and 1,6-dimethyl-1,4-diazepan-6-amine was obtained by vacuum distillation. NMR characterization data: 11H NMR (400 MHz, CDCl3) δ = 2.88 - 2.83 (m, 2H), 2.82 - 2.73 (m, 2H), 2.68 (d, 2H), 2.52 (d, 2H), 2.20 (s, 3H), 1.29 (s, 3H), which is consistent with the target product.

[0068] Example 9

[0069] Synthesis of 6 - ethyl - 1,4 - dimethyl - 1,4 - diazaheptan - 6 - amine I - 11

[0070]

[0071] 2 - Nitro - 2 - ethyl - propanediol (100 mmol, 14.92 g), dimethylethylenediamine (100 mmol, 8.82 g) and ethyl acetate (100 mL) were successively added to a 300 mL high - pressure reactor. After sealing, the reaction was carried out at 60 °C for 16 h with a magnetic stirring speed of 500 r / min. After the reaction, the high - pressure reactor was immersed in an ice - water bath for 0.5 h. Then, the reactor was opened and 3 g of 10 wt% palladium on silica was added. After sealing again, nitrogen was introduced to displace the air, and finally hydrogen (5 MPa) was introduced. The high - pressure reactor was reacted at 50 °C for 24 h with a magnetic stirring speed of 500 r / min. After the reaction, the high - pressure reactor was immersed in an ice - water bath for 0.5 h. Then, the reaction solution was filtered, and the filter cake was washed with ethyl acetate (30 mL × 2). After combining the washing solution and the filtrate, the solvent ethyl acetate was removed completely using a rotary evaporator, and 6 - ethyl - 1,4 - dimethyl - 1,4 - diazaheptan - 6 - amine was obtained by vacuum distillation. NMR characterization data: 1 1HNMR (400 MHz, CDCl3) δ = 2.92 - 2.84 (m, 2H), 2.83 - 2.75 (m, 2H), 2.74 (d, 2H), 2.54 (d, 2H), 2.25 (s, 6H), 1.32 (q, 2H), 0.88 (t, 3H), which is consistent with the target product.

[0072] Application Example 1

[0073] 30 g of the heptacyclic organic polyamine obtained in Examples 1 - 9 and 70 g of deionized water were added to a 250 mL round - bottom flask. After stirring evenly, a carbon dioxide - nitrogen mixture with a carbon dioxide volume content of 15% was slowly introduced. The flow rate of the mixture was 100 mL / min, the pressure was 0.1 MPa, and the oil bath temperature was 40 °C. The inlet and outlet flow rates were recorded in real - time using a gas flowmeter. The test results of the carbon dioxide absorption performance of the heptacyclic organic polyamine absorbent are shown in Table 1:

[0074] Table 1 Carbon Dioxide Absorption Performance of Heptacyclic Organic Polyamine Absorbent

[0075]

[0076]

[0077] As can be seen from Table 1, the heptacyclic organic polyamine absorbent provided by the present invention has excellent absorption effect on carbon dioxide.

[0078] Application Example 2

[0079] Under the condition of magnetic stirring, a 250 mL round-bottom flask containing 100 g of the heptacyclic organic polyamine absorbent saturated with carbon dioxide in Application Example 1 was placed in an oil bath, and the temperature of the oil bath was raised to 120 °C. The inlet and outlet gas flows were recorded in real time with a gas flowmeter. The test results of the regeneration performance of the heptacyclic organic polyamine absorbent are shown in Table 2:

[0080] Table 2 Regeneration performance of the heptacyclic organic polyamine absorbent

[0081]

[0082]

[0083] As can be seen from Table 2, the heptacyclic organic polyamine absorbent provided by the present invention desorbs carbon dioxide quickly and completely.

[0084] In view of this, the object of the present invention is to provide a class of heptacyclic organic polyamines as carbon dioxide absorbents and a preparation method of such heptacyclic organic polyamines. The heptacyclic organic polyamine absorbent provided by the present invention has a high absorption capacity, rapid desorption, and excellent cyclic use performance.

[0085] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

[0086] The numerical values and ranges used in the present invention are clarifying rather than restrictive. Although the data and data ranges stated in the specific embodiments of the present invention have been measured and recorded as accurately as possible, these data and data ranges inevitably contain certain errors, which are necessarily caused by the standard deviations commonly existing in various tests.

Claims

1. A heptacyclic organic polyamine, characterized in that, It has the structure shown in Formula I: In the formula I, R 1 , R 2 and R 3 are H or C1-C3 alkyl.

2. The heptacyclic organic polyamine according to claim 1, characterized in that, It has the structure shown in any one of Formulae I-1 to I-12:

3. The preparation method of a heptacyclic organic polyamine according to claim 1 or 2, characterized in that, It includes the following steps: Mix Compound 1 and Compound 2 in an organic solvent, carry out a cyclization reaction, then add a transition metal catalyst to the reaction mixture and introduce hydrogen to carry out a pressure hydrogenation reaction to obtain the seven-membered cyclic organic polyamine; In the said Compound 1, R 1 is H or C1-C3 alkyl; In the said Compound 2, R 2 and R 3 are H or C1-C3 alkyl groups.

4. The preparation method according to claim 3, characterized in that, The molar ratio of Compound 1 to Compound 2 is 1:(0.1 to 10).

5. The preparation method according to claim 3, characterized in that, The transition metal catalyst is a nickel-based catalyst or a palladium-based catalyst; the added mass of the transition metal catalyst is 0.1 to 20% of the total mass of Compound 1 and Compound 2.

6. The preparation method according to any one of claims 3, characterized in that, The temperature of the cyclization reaction is from 20 to 80 °C and the time is from 1 to 24 h.

7. The preparation method according to any one of claims 3, characterized in that, The temperature of the pressure hydrogenation reaction is from 20 to 120 °C, the time is from 1 to 48 h, and the hydrogen pressure is from 0.1 to 10 MPa.

8. The preparation method according to any one of claims 3, characterized in that, The organic solvent is one or a mixture of two or more of methanol, ethanol, isopropanol, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, and ethyl acetate.

9. Use of the seven-membered cyclic organic polyamine according to claim 1 or 2 or the seven-membered cyclic organic polyamine prepared by the preparation method according to any one of claims 3 to 8, characterized in that The seven-membered cyclic organic polyamine is used as an absorbent in the absorption of carbon dioxide.

10. The application according to claim 9, characterized in that The absorbent includes a seven-membered cyclic organic polyamine and water. By mass percentage, the mass percentage of the seven-membered cyclic organic polyamine is 1 to 50%, and water accounts for 50 to 99%.

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