Preparation method and application of pyridine amino-functionalized deep-eutectic solvent

Abstract

The invention discloses a preparation method of a pyridine amino-functionalized deep-eutectic solvent and application of the pyridine amino-functionalized deep-eutectic solvent in absorption and removal of CO2. According to the pyridine amino-functionalized deep-eutectic solvent DESs, 2-aminopyridine is used as a hydrogen bond acceptor; ethanolamine MEA or diethanolamine DEA is used as a hydrogen bond donor, and the eutectic solvent which stably exists at room temperature is formed by simple heating and stirring. According to the invention, under the conditions of 25 DEG C and 1.0 bar, the absorption capacity of the amino-functionalized DESs to CO2 is up to 0.202 g / g; the synthesized DESs can basically realize CO2 absorption balance within 150 minutes; water content experiments show that after a certain amount of water is added, the CO2 absorption performance of DES is gradually reduced along with the increase of the water content, but good absorption performance is still kept. The amido-functionalized DESs disclosed by the invention not only has the characteristics of simplicity in synthesis, good cycle stability, environmental protection and the like, but also has excellent absorption performance at normal temperature and normal pressure, and can be applied to removal of CO2 in industrial tail gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas absorbent preparation, and particularly relates to a preparation method of a pyridine-based amino-functionalized deep eutectic solvent and its application in efficient CO2 absorption. Background Art

[0002] By absorbing CO2, the concentration of CO2 in the atmosphere can be reduced, thereby reducing the greenhouse effect and slowing down the rate of global temperature rise.

[0003] Carbon capture, utilization, and storage technology (CCUS) is a key technology to address global challenges such as climate change and carbon emissions. CO2 capture plays a crucial role in CCUS technology. CO2 capture technologies include pre-combustion capture, oxy-fuel combustion technology, and post-combustion capture. Among them, the post-combustion capture technology has mature processes and wide applications, and the chemical absorption method is one of the most commonly used methods. However, traditional organic amine absorbents have disadvantages such as strong volatility, low absorption efficiency, and strong pollution. The high viscosity, complex synthesis, and high cost of ionic liquids (ILs) also hinder their practical applications. As a green solvent similar to ILs, deep eutectic solvents (DESs) have advantages such as low vapor pressure, high thermal stability, easy degradation, and low cost, and are widely used in the field of gas capture and separation, especially showing advantages such as high absorption rate, low toxicity, and good renewability in CO2 capture. DESs are formed by hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs) through hydrogen bonding and other interactions, and are a kind of low-melting-point mixed solvent. DESs have the advantages of ionic liquids, such as low toxicity, renewability, simple preparation, and low cost, and are considered green solvents, showing excellent performance in CO2 absorption and separation. By reasonably designing and selecting HBAs and HBDs, efficient and green CO2 absorbents can be prepared to achieve high-performance selective absorption of CO2 in flue gas.

[0004] Pyridine-based compounds are a kind of nitrogen-containing six-membered heterocyclic compounds with aromaticity and uniform π electron cloud distribution. Therefore, pyridine-based compounds maintain the structural stability in many chemical reactions and practical applications and are not easily decomposed or deteriorated. Existing studies have shown that the pyridine nitrogen in aminopyridine is more likely to be deprotonated than the amino group. In addition, the hydrogen bond formed between aminopyridine and hydroxy-containing solvent molecules can increase the electron cloud density of the amine nitrogen atom, and this effect is beneficial to the deprotonation reaction of the amino group. Therefore, it is considered to use aminopyridine as HBAs to inhibit the increase in viscosity and improve the absorption and cycling ability of amino-functionalized DESs by changing the proton transfer site.

[0005] In addition, previous studies have shown that the hydrogen bond formed between aminopyridine and hydroxy solvents can increase the electron density on the amine nitrogen atom and contribute to the deprotonation process of the amino group. Based on this, the present invention further uses an amine solution containing a hydroxyl group as the HBD, which is used in combination with aminopyridine, and can further improve the carbon dioxide absorption capacity of the amino-functionalized DES. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the pyridine nitrogen of aminopyridine is more prone to deprotonation than the amino group. In addition, the hydrogen bond formed between aminopyridine and hydroxy solvent molecules can increase the electron cloud density of the amine nitrogen atom, and this effect is beneficial to the deprotonation reaction of the amino group. Therefore, the present invention uses aminopyridine as the HBAs to inhibit the increase in viscosity and improve the absorption and cycling ability of amino-functionalized DESs by changing the proton transfer site.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A pyridine-based amino-functionalized deep eutectic solvent absorbent, including hydrogen bond acceptors HBAs and hydrogen bond donors HBDs, or including hydrogen bond acceptors HBAs, hydrogen bond donors HBDs and water, is prepared by a simple heating and stirring method.

[0009] The hydrogen bond acceptor HBAs is 2-aminopyridine (2-AP);

[0010] The hydrogen bond donor HBDs is ethanolamine (MEA) or diethanolamine (DEA);

[0011] When the pyridine-based amino-functionalized deep eutectic solvent absorbent contains water, the water content is 5-20 wt% of the total mass of the hydrogen bond acceptor and the hydrogen bond donor.

[0012] The structural formulas of the above compounds are as follows:

[0013]

[0014] Among them, in the pyridine-based amino-functionalized DESs, the molar ratio of HBAs:HBDs is 1:1 to 1:7.

[0015] Among them, the pyridine-based amino-functionalized DESs are homogeneous liquids at room temperature, and the melting point is much lower than that of the single component.

[0016] Among them, the MEA and DEA are directly purchased from reagent suppliers and do not require further purification.

[0017] The preparation method of the above pyridine-based amino-functionalized DESs absorbent is as follows:

[0018] Add a hydrogen bond donor and a hydrogen bond acceptor, or a hydrogen bond acceptor, a hydrogen bond donor, and water, in proportion to a glass bottle. After sealing, transfer it to a constant temperature oil bath and stir strongly at 600 - 800 rpm for 3 - 4 h under the condition of 80 - 100 °C. After turning off the heating, take out the glass bottle and let it stand. After it naturally cools to room temperature, the formed homogeneous solution is the pyridine-based amino-functionalized deep eutectic solvent DESs.

[0019] Regarding the application of the amino-functionalized deep eutectic solvent absorbent described in the present invention for absorbing and removing CO2, the specific absorption application method is as follows:

[0020] Use a "double-chamber" gas capture device to conduct an absorption experiment on CO2. Weigh a certain mass (w) of the pyridine-based amino-functionalized deep eutectic solvent absorbent with an analytical balance (accuracy of ±0.0001 g) and put it into the absorption tank. After sealing the device, place it in a constant temperature water bath. Set the required temperatures (25 °C, 40 °C, 60 °C, and 80 °C in sequence) to conduct gas absorption experiments at different temperatures.

[0021] Similarly, weigh a certain mass of the pyridine-based amino-functionalized deep eutectic solvent absorbent after adding water and put it into the absorption tank. After sealing the device, place it in a constant temperature water bath and set the required temperature to conduct a gas absorption comparison experiment with different water contents.

[0022] In the pyridine-based amino-functionalized deep eutectic solvent absorbent after adding water, the water addition amount is 0 - 20% of the mass of the pyridine-based amino-functionalized deep eutectic solvent absorbent.

[0023] The present invention has the following advantages:

[0024] (1) The prepared pyridine-based amino-functionalized DESs absorbent has a simple and easy synthesis process, low production cost, and does not cause environmental pollution during the preparation process.

[0025] (2) The prepared pyridine-based amino-functionalized DESs absorbent exhibits excellent CO2 absorption performance.

[0026] (3) The prepared pyridine-based amino-functionalized DESs absorbent not only has good recycling performance but also strong stability.

[0027] (4) The prepared pyridine-based amino-functionalized DESs absorbent can achieve efficient CO2 absorption at room temperature and is suitable for removing carbon dioxide from most industrial tail gases. Description of the Drawings

[0028] Figure 1Schematic diagram of the gas absorption experimental device (R1-R4: regulating valve; PV and SV: pressure sensors; WB: constant temperature water bath; GB: gas buffer tank; GA: gas capture tank; MS: magnetic stirrer; CP: computer; VP: vacuum pump)

[0029] Figure 2 The CO2 absorption capacity of the obtained DESs when using different molar ratios of 2-AP:MEA;

[0030] Figure 3 The effect of different absorption temperatures on the CO2 absorption capacity of DESs (2-AP:MEA=1:5);

[0031] Figure 4 The effect of water content on the CO2 absorption capacity of DESs (2-AP:MEA=1:5);

[0032] Figure 5 This is the cyclic absorption performance of DESs (2-AP:MEA=1:5). DETAILED DESCRIPTION

[0033] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0034] In this study, a "double-chamber" gas capture device was used to conduct CO2 absorption and desorption experiments on DESs. The schematic diagram of the device is shown in Figure 1 The device consists of two stainless steel pressure vessels, of which the gas buffer tank (GB) has an effective volume of 122.100 cm 3 , recorded as VGS. The other is a gas capture tank (GA) with a volume of 46.390cm 3 (VGA), with a built-in magnetic stirrer of fixed volume. Both tanks are placed in a high-precision constant temperature water bath device (WB, temperature control accuracy ±0.1K), which can achieve constant temperature control in the range of 273.15-353.15K. The bottom of the capture tank is equipped with a magnetic stirrer (MS) with a speed set to 800rpm. The cache tank and the capture tank are respectively connected to high-precision pressure sensors (SV, PV, accuracy ±0.2%), which collect and transmit the air pressure data in the two tanks in real time to the electronic computer (CP) for online analysis. The vacuum pump (VP) is used for vacuuming the device and residual CO2 treatment.

[0035] Before the experiment, the sample to be tested with the target mass (m) was accurately weighed using an electronic balance and placed at the bottom of the gas capture tank (GA). After encapsulating the gas buffer tank (GB) and the capture tank (GA), they were horizontally placed in a constant temperature water bath device, and the capture tank was adjusted to be located in the central area of the magnetic stirrer. First, the water bath temperature was set to the experimental required conditions. After the temperature stabilized (fluctuation ≤ ±0.1 K), the vacuum pump was started, with R1 and R2 closed. R3 and R4 were sequentially opened to make the PV reading negative, that is, the device was kept in a vacuum state. After maintaining for 20 min, the initial pressure pGA of the capture tank was recorded. Subsequently, R3 and R4 were closed and the air extraction was stopped. CO2 gas was filled into the buffer tank by controlling R1 until the pressure stabilized for 2 min, and then the air pressure pGB of the buffer tank was recorded. Then, by adjusting R3, the required amount of CO2 gas pressure was introduced into the capture tank. Immediately after that, the magnetic stirrer was turned on to stir the DESs to make it fully contact with CO2. Finally, after the readings of the pressure sensor tended to be stable, the air pressure values of the capture tank were recorded as pa (a = 2, 3, 4, …, n) and the air pressure of the buffer tank was recorded as pb (b = 2, 3, 4, …, n). Then the partial pressure of CO2 gas in the capture tank was pGAa = pa - pGA, and the partial pressure of CO2 gas in the buffer tank was pGBb = pb - pGb. The absorption amount μ of CO2 was calculated by the following formula:

[0036]

[0037] Among them, respectively represent the CO2 gas density (g / cm 3 ) at pGB, pGBb, and pGAa. The specific values can be referred to the NIST Chemistry WebBook database. m represents the mass (g) of the sample to be tested, ρ represents the density (g / cm 3 ) of the sample to be tested, and VGA and VGB respectively represent the effective volumes (cm 3 ) of the gas capture tank and the buffer tank.

[0038] Example 1:

[0039] 1.2314 g of 2-AP and 2200 μL of MEA were taken and added to a glass bottle, placed in a 20 mL reaction flask, and a magnetic stir bar was put in. After sealing, it was transferred to a constant temperature oil bath. After preheating for 5 min to promote the melting of the components, it was continuously stirred at 80 °C at a speed of 600 rpm for 3 h. After stopping heating and stirring, it was naturally cooled to room temperature. Finally, a clear and transparent homogeneous solution was formed, which was the required pyridine-based DESs absorbent (2-AP:MEA = 1:1).

[0040] Weigh 0.1899 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:1) and place it in the absorption tank, then stir it with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.083 g / g.

[0041] Example 2:

[0042] Take 2.2107 g of 2-AP and 2830 μL of MEA and add them to a glass bottle placed in a 20 mL reaction flask, then put in a magnetic stirrer. After sealing, transfer it to a constant-temperature oil bath. After preheating for 5 min to promote the melting of the components, stir continuously at 80 °C and 600 rpm for 3 h. After stopping heating and stirring, let it cool naturally to room temperature. The finally formed clear and transparent homogeneous solution is the required pyridine-based DESs absorbent (2-AP:MEA = 1:2).

[0043] Weigh 0.2188 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:2) and place it in the absorption tank, then stir it with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.092 g / g.

[0044] Example 3:

[0045] Take 2.2107 g of 2-AP and 3943 μL of MEA and add them to a glass bottle placed in a 20 mL reaction flask, then put in a magnetic stirrer. After sealing, transfer it to a constant-temperature oil bath. After preheating for 5 min to promote the melting of the components, stir continuously at 80 °C and 600 rpm for 3 h. After stopping heating and stirring, let it cool naturally to room temperature. The finally formed clear and transparent homogeneous solution is the required pyridine-based DESs absorbent (2-AP:MEA = 1:3).

[0046] Weigh 0.2182 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:3) and place it in the absorption tank, then stir it with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.121 g / g.

[0047] Example 4:

[0048] Take 1.9504 g of 2-AP and 4988 μL of MEA and add them to a glass bottle placed in a 20 mL reaction flask, then put a magnetic stirrer. After sealing, transfer it to a constant temperature oil bath. After preheating for 5 min to promote the melting of the components, continuously stir at 80 °C and 600 rpm for 3 h. After stopping heating and stirring, naturally cool to room temperature. The finally formed clear and transparent homogeneous solution is the required pyridine-based DESs absorbent (2-AP:MEA = 1:4).

[0049] Weigh 0.1923 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:4) and place it in the absorption tank, then stir it with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.128 g / g.

[0050] Example 5:

[0051] Take 0.6008 g of 2-AP and 1920 μL of MEA and add them to a glass bottle placed in a 20 mL reaction flask, then put a magnetic stirrer. After sealing, transfer it to a constant temperature oil bath. After preheating for 5 min to promote the melting of the components, continuously stir at 80 °C and 600 rpm for 3 h. After stopping heating and stirring, naturally cool to room temperature. The finally formed clear and transparent homogeneous solution is the required pyridine-based DESs absorbent (2-AP:MEA = 1:5).

[0052] Weigh 0.2958 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:5) and place them in an absorption tank, then stir with a magnetic stir bar. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (∼2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the highest CO2 absorption capacity is 0.202 g / g.

[0053] After absorption saturation, evacuate the residual gas in the stainless-steel tank, and raise the temperature of the constant temperature water bath to 80 °C. After continuously evacuating for 120 min, introduce N2 to exhaust all the CO2 gas in the stainless-steel tank. Lower the temperature to 25 °C. After the temperatures of all parts are stable, continue the above absorption experiment. After repeating this process multiple times, the cyclic use performance can be investigated. After the absorbent is reused 6 times, the absorption capacity can still reach 0.184 g / g. See specifically Figure 5 。

[0054] Example 6:

[0055] Take 1.2844 g of 2-AP and 4927 μL of MEA and add them to a glass bottle placed in a 20 mL reaction flask, then put in a magnetic stir bar. After sealing, transfer it to a constant temperature oil bath. After preheating for 5 min to promote the melting of the components, stir continuously at 80 °C at a speed of 600 rpm for 3 h. After stopping heating and stirring, cool naturally to room temperature. The finally formed clear and transparent homogeneous solution is the required pyridine-based DESs absorbent (2-AP:MEA = 1:6).

[0056] Weigh 0.1825 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:6) and place them in an absorption tank, then stir with a magnetic stir bar. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (∼2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the highest CO2 absorption capacity is 0.179 g / g.

[0057] Example 7:

[0058] Take 1.800 g of 2-AP and 8056 μL of MEA and add them to a glass bottle placed in a 20 mL reaction flask. Then put a magnetic stir bar into the flask, seal it, and transfer it to a thermostatic oil bath. After preheating for 5 min to promote the melting of the components, stir continuously at 80 °C and 600 rpm for 3 h. After stopping heating and stirring, let it cool naturally to room temperature. Finally, a clear and transparent homogeneous solution is formed, which is the required pyridine-based DESs absorbent (2-AP:MEA = 1:7).

[0059] Weigh 0.2133 g of the above-prepared amino-functionalized DESs (2-AP:MEA = 1:7) and place it in an absorption tank and stir it with a magnetic stir bar. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After absorbing for 240 min (1.0 bar), the maximum CO2 absorption capacity is 0.163 g / g.

[0060] Example 8:

[0061] Weigh 0.2541 g of the amino-functionalized DESs (2-AP:MEA = 1:5) prepared in the same method as in Example 5 and place it in an absorption tank and stir it with a magnetic stir bar. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 40 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After absorbing for 240 min (1.0 bar), the maximum CO2 absorption capacity is 0.185 g / g.

[0062] Example 9:

[0063] Weigh 0.2710 g of the amino-functionalized DESs (2-AP:MEA = 1:5) prepared in the same method as in Example 5 and place it in an absorption tank and stir it with a magnetic stir bar. After sealing the absorption tank and the gas storage tank, place them in a super-constant temperature water bath with precise temperature control at 60 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After absorbing for 240 min (1.0 bar), the maximum CO2 absorption capacity is 0.154 g / g.

[0064] Example 10:

[0065] Weigh 0.2090 g of the amino-functionalized DESs (2-AP:MEA = 1:5) prepared by the same method as in Example 5 and place them in an absorption tank, then stir with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super constant temperature water bath with precise temperature control at 80 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.138 g / g.

[0066] Example 11:

[0067] Weigh 0.9500 g of the amino-functionalized DESs (2-AP:MEA = 1:5) prepared in Example 5 and place them in a glass bottle. Drop 0.0500 g of pure water into it and stir evenly with a magnetic stirrer, denoted as 2-AP:MEA = 1:5 + 5 wt% H2O. Then weigh 0.2120 g of 2-AP:MEA = 1:5 + 5 wt% H2O and place it in an absorption tank, and stir with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.183 g / g.

[0068] Example 12:

[0069] Weigh 0.9000 g of the amino-functionalized DESs (2-AP:MEA = 1:5) prepared in Example 5 and place them in a glass bottle. Drop 0.1000 g of pure water into it and stir evenly with a magnetic stirrer, denoted as 2-AP:MEA = 1:5 + 10 wt% H2O. Then weigh 0.1916 g of 2-AP:MEA = 1:5 + 10 wt% H2O and place it in an absorption tank, and stir with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.172 g / g.

[0070] Example 13:

[0071] Weigh 0.8000 g of the amino-functionalized DESs (2-AP:MEA = 1:5) prepared in Example 5 and place it in a glass bottle. Drop 0.2000 g of pure water into it and stir evenly with a magnetic stir bar, denoted as 2-AP:MEA = 1:5 + 20 wt% H2O. Then weigh 0.2150 g of 2-AP:MEA = 1:5 + 20 wt% H2O and place it in an absorption tank, and stir with a magnetic stir bar. After sealing the absorption tank and the gas storage tank, place them in a super constant temperature water bath with precise temperature control at 25°C. First, fill the gas storage tank with enough CO2 (∼2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.154 g / g.

[0072] Figure 2 It can be seen that compared with Examples 1-7, when 2-AP:MEA = 1:5, the pyridine-based DESs have the best absorption effect on CO2.

[0073] Figure 3 It can be seen that compared with Examples 5, 8-10, the pyridine-based DESs at different absorption temperatures have different absorption effects on CO2, and have the best absorption effect at 25°C.

[0074] Figure 4 It can be seen that compared with Examples 5, 11-13, the water content will affect the absorption effect of amino-functionalized DESs on CO2. Trace water (<5 wt%) has limited influence on the CO2 gas absorption performance of pyridine-based DESs, but excessive water will significantly reduce its absorption capacity.

[0075] Example 14:

[0076] Take 0.9375 g of 2-AP and 4775 μL of DEA and add them to a glass bottle placed in a 20 mL reaction flask and put a magnetic stir bar. After sealing, transfer it to a thermostatic oil bath. After preheating for 5 min to promote the melting of the components, stir continuously at 80°C at a speed of 600 rpm for 3 h. After stopping heating and stirring, cool it naturally to room temperature. The finally formed clear and transparent homogeneous solution is the required pyridine-based DESs absorbent (2-AP:DEA = 1:5).

[0077] Weigh 0.1972 g of the above-prepared amino-functionalized DESs (2-AP:DEA = 1:5) and place them in the absorption tank, then stir with a magnetic stirrer. After sealing the absorption tank and the gas storage tank, place them in a super constant temperature water bath with precise temperature control at 25 °C. First, fill the gas storage tank with enough CO2 (~2.0 bar). After the pressure stabilizes, fill the absorption tank with CO2. The absorption time for every 0.1 bar is about 20 min. After 240 min of absorption (1.0 bar), the maximum CO2 absorption capacity is 0.086 g / g.

Claims

1. A pyridine-based amino-functionalized deep eutectic solvent, characterized in that, Comprising a hydrogen bond acceptor and a hydrogen bond donor; or, comprising hydrogen bond acceptors (HBAs), hydrogen bond donors (HBDs) and water; The hydrogen bond acceptors (HBAs) are 2-aminopyridine (2-AP); The hydrogen bond donors (HBDs) are monoethanolamine (MEA) or diethanolamine (DEA); Wherein, the molar ratio of HBAs:HBDs is 1:1 to 1:

7.

2. The pyridine-based amino-functionalized deep eutectic solvent according to claim 1, wherein When the pyridine-based amino-functionalized deep eutectic solvent absorbent contains water, the water content is 5-20 wt% of the total mass of the hydrogen bond acceptor and the hydrogen bond donor.

3. The pyridine-based amino-functionalized deep eutectic solvent according to claim 1, wherein, It is a homogeneous liquid at room temperature, and its melting point is much lower than that of the single component.

4. The preparation method of the pyridine-based amino-functionalized deep eutectic solvent according to any one of claims 1 to 3, characterized in that, The steps are as follows: Add the hydrogen bond donor and the hydrogen bond acceptor, or, the hydrogen bond acceptor, the hydrogen bond donor and water, into a glass bottle in proportion, seal it and transfer it to a constant temperature oil bath and stir. After stirring is completed, turn off the heating and take out the glass bottle and let it stand. After it cools naturally to room temperature, the formed homogeneous solution is the pyridine-based amino-functionalized deep eutectic solvent (DESs).

5. The preparation method of the pyridine-based amino-functionalized deep eutectic solvent according to claim 4, wherein, The temperature of the oil bath is 80-100 °C.

6. The preparation method of the pyridine-based amino-functionalized deep eutectic solvent according to claim 4, wherein, The stirring speed is 600-800 rpm and the time is 3-4 h.

7. The preparation method of the pyridine-based amino-functionalized deep eutectic solvent according to claim 4, characterized in that, The hydrogen bond acceptors (HBAs) are 2-aminopyridine (2-AP); the hydrogen bond donors (HBDs) are monoethanolamine (MEA) or diethanolamine (DEA), Wherein, the molar ratio of HBAs:HBDs is 1:1 to 1:7; The water content is 5-20 wt% of the total mass of the hydrogen bond acceptor and the hydrogen bond donor.

8. Application of the pyridine-based amino-functionalized deep eutectic solvent according to claim 1 in the absorption and removal of CO2.

9. The application according to claim 8, characterized in that, The steps are: Use a "double-chamber" gas capture device, weigh a certain mass of the pyridine-based amino-functionalized deep eutectic solvent as an absorbent and put it into the absorption tank, seal the device and put it into a constant temperature water bath. After setting the required temperature, carry out gas absorption experiments at different temperatures.

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