Application of 4-aminopiperidine derivative in trapping sulfur dioxide in airflow

Abstract

The invention provides an application of a 4-aminopiperidine derivative in trapping sulfur dioxide in airflow. A 4-aminopiperidine derivative is used as a sulfur dioxide trapping agent, the 4-aminopiperidine derivative or inorganic acid salt or organic acid salt of the 4-aminopiperidine derivative is dissolved in a solvent to prepare a solution, then sulfur dioxide gas or gas containing sulfur dioxide is introduced, and after the sulfur dioxide is absorbed to be saturated, the sulfur dioxide trapping agent is obtained. The sulfur dioxide is desorbed by vacuum heating and N2 or high-temperature steam introduction methods. The 4-aminopiperidine derivative provided by the invention shows good sulfur dioxide absorption capacity and cycle performance, does not generate secondary pollutants in adsorption and regeneration processes, and has industrial application value.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection gas purification, and particularly relates to the application of a 4-aminopiperidine derivative in capturing sulfur dioxide in a gas stream. Background Art

[0002] With the increasing demand for electric power energy in industrial development, sulfur dioxide in the tail gas generated by coal combustion in power plants has become one of the main air pollutants. In addition, sulfur dioxide is generated during the high-temperature roasting or smelting of sulfide ores in the metallurgical industry, and sulfur dioxide is released in processes such as sulfuric acid manufacturing, petroleum refining, and sulfur recovery in chemical production.

[0003] Sulfur dioxide is oxidized to sulfur trioxide in the air, combines with water to form acid rain, and damages soil, water bodies, and buildings; sulfur dioxide reacts with ammonia and volatile organic compounds in the air to form sulfate aerosols; sulfur dioxide poses a serious hazard to human health, irritating the respiratory mucosa, triggering diseases such as asthma and bronchitis, damaging the respiratory system, and also causing cardiovascular diseases and having a carcinogenic risk.

[0004] Therefore, capturing sulfur dioxide from tail gas is of great significance for environmental protection. Currently, sulfur dioxide capture technologies mainly include dry, semi-dry, and wet desulfurization technologies. Dry desulfurization technology refers to that both the desulfurizer and the desulfurized product are solid powders or particulate matters. For example, using activated carbon to adsorb sulfur dioxide, the process operation is simple, but there are problems such as low adsorption capacity (<100mg / g), frequent replacement of the adsorbent required, high regeneration energy consumption (accounting for 30%-40% of the total system energy consumption), damage to the activated carbon caused by high-temperature regeneration, short service life, and high maintenance costs. Semi-dry desulfurization technology means that adding a small amount of water during the desulfurization process improves the desulfurization efficiency, and at the same time the desulfurized product is still solid. For example, spraying lime slurry into the flue gas, SO2 reacts with Ca(OH)2 to form CaSO3. Its disadvantages are low absorbent utilization rate (60%-80%), need for excessive dosing; sensitive to operating parameters (temperature, humidity), poor stability; complex composition of the desulfurized product, and difficult to recycle. Wet desulfurization technology dissolves the desulfurizer in a solvent, and then makes the gas stream containing sulfur dioxide fully contact with the solution containing the desulfurizer. The desulfurizer chemically reacts with sulfur dioxide to keep sulfur dioxide in the solution, thus achieving the desulfurization effect. This desulfurization technology has simple operation and strong applicability, and is currently the most widely used desulfurization technology. Wet desulfurization technology mainly includes limestone method, ammonia absorption method, and ionic liquid method, etc. The limestone method has the disadvantages of easy scaling and blockage of equipment pipelines, frequent maintenance required, low purity of the desulfurized product gypsum, limited economic value, a large amount of wastewater to be treated, and high operating costs. The ammonia absorption method has the risk of secondary pollution caused by easy volatilization of ammonia gas. The ionic liquid method has the disadvantages of difficult preparation, high acquisition cost, large viscosity, poor fluidity, or low absorption capacity per unit mass due to too large molecular weight, resulting in great limitations in industrial applications. For example, Patent CN102160963A discloses a method for desulfurization with azolium ionic liquid. The preparation method of azolium ionic liquid is complex, requires the use of ion exchange resin, and has a high cost. Moreover, the prepared azolium ionic liquid has a large molecular weight. For example, tetradecyltrihexylphosphonium imidazole, at 0.1Mpa SO2 and 20°C, its mass absorption capacity is only 0.558g SO2 / g substrate. As another wet desulfurization technology, the absorbent of the organic amine method is mainly piperazine derivatives, including 1,4-dihydroxyethylpiperazine, N-hydroxyethylpiperazine, 1,4-dihydroxypropylpiperazine. For example, Patent CN112107967A discloses a method for preparing 1,4-dihydroxyethylpiperazine as a sulfur dioxide absorbent, but it needs to use highly toxic ethylene oxide gas, and the obtained absorbent is a mixture. The impurities N-hydroxyethylpiperazine and trihydroxyethylpiperazine in it have a negative impact on the absorption capacity and desorption rate.

[0005] Therefore, it is very necessary to develop a new type of sulfur dioxide capture technology with high efficiency and recyclability. Summary of the Invention

[0006] The object of the present invention is to provide a method for capturing sulfur dioxide in a gas stream by using 4-aminopiperidine derivatives to overcome the defects of the above-mentioned prior art. The present invention aims to provide a new application of 4-aminopiperidine derivatives in capturing sulfur dioxide in a gas stream.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] The present invention provides an application of 4-aminopiperidine derivatives in capturing sulfur dioxide in a gas stream. Specifically, 4-aminopiperidine derivatives are used as sulfur dioxide capture agents.

[0009] The present invention provides a method for capturing sulfur dioxide in a gas stream by using 4-aminopiperidine derivatives, which includes the following steps: dissolving 4-aminopiperidine derivatives or their inorganic salts or organic salts in a solvent to form a solution, and then introducing sulfur dioxide gas or a gas containing sulfur dioxide until the sulfur dioxide is absorbed by the solution.

[0010] Further, the general structural formula of the 4-aminopiperidine derivative is as follows:

[0011]

[0012] where n = 1, 2, 4.

[0013] Preferably, the 4-aminopiperidine derivative is 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol, 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol, 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol.

[0014] Further, the inorganic acids include hydrochloric acid, sulfuric acid, and phosphoric acid. The organic acids include formic acid, acetic acid, lactic acid, malic acid, and citric acid.

[0015] Further, the solvent is water and / or sulfolane.

[0016] Further, the mass ratio of the 4-aminopiperidine derivative to the solvent is 1:0.5 - 19, preferably 1:1 - 9.

[0017] Further, the molar ratio of the 4-aminopiperidine derivative to the inorganic acid or organic acid is 1:(0.2 - 4), preferably 1:(0.3 - 0.7).

[0018] Further, the absorption temperature of sulfur dioxide is 20 - 60 °C, and the absorption time is 0.5 - 3 h.

[0019] The method of the present invention can selectively absorb SO2 in the gas stream and has a very low or no absorption of CO2 in the gas stream.

[0020] In the method of the present invention, by introducing N2 or water vapor into the solution that has absorbed sulfur dioxide or heating it at 60-80 °C for 0.5-2 h under vacuum conditions, sulfur dioxide can be desorbed, and the regenerative recycling of the capturer 4-aminopiperidine derivative can be realized.

[0021] The present invention also provides an absorbent for capturing sulfur dioxide, which absorbent contains the described 4-aminopiperidine derivative or their inorganic salts or organic salts.

[0022] In some embodiments, the 4-aminopiperidine derivative solution can be a sulfolane solution of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol. In some embodiments, the 4-aminopiperidine derivative solution can be an aqueous solution of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol. In some embodiments, the 4-aminopiperidine derivative solution can be an aqueous hydrochloric acid solution of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol. In some embodiments, the 4-aminopiperidine derivative solution can be an aqueous sulfuric acid solution of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol. In some embodiments, the 4-aminopiperidine derivative solution can be an aqueous lactic acid solution of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0023] In the molecule of the 4-aminopiperidine derivative of the present invention, there are two tertiary amine structures. Tertiary amines have the ability to efficiently capture sulfur dioxide, and compared with primary amines and secondary amines, the energy consumption in the regeneration process of tertiary amines is lower. Therefore, it is very suitable as a sulfur dioxide capturer.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention uses 4-aminopiperidine derivatives as sulfur dioxide capturers. The 4-aminopiperidine derivatives have a large absorption capacity, low regeneration energy consumption, and good adsorption and desorption cycle performance, and can still maintain a high adsorption capacity after multiple adsorption and desorption cycles.

[0026] 2. The present invention uses 4-aminopiperidine derivatives as sulfur dioxide capturers. Its preparation method is simple, the raw materials are easy to obtain, and it has the advantage of low cost. The 4-aminopiperidine derivatives with the specific structures provided by the present invention all have a certain desulfurization effect, and can achieve a good desorption rate at a relatively low temperature, thereby realizing the recycling of the capturer, and having the characteristics of environmental friendliness and low cost, no secondary pollutants are generated, and it has a good application prospect. Description of the Drawings

[0027] Figure 11H-NMR spectrum of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0028] Figure 2 1H-NMR spectrum of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol.

[0029] Figure 3 1H-NMR spectrum of 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol.

[0030] Figure 4 Flow chart of the sulfur dioxide capture method provided by the present invention.

[0031] Detailed Description of Specific Embodiments

[0032] The present invention will be described in detail below with reference to specific drawings and embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0033] The 4-aminopiperidine derivative (Compound I) used in the present invention is prepared according to the method described in Patent Application No. 202410665367.9:

[0034]

[0035] Wherein, n = 1, 2, 4.

[0036] This method uses a 4-aminopyridine quaternary ammonium salt derivative as a raw material, and catalytic hydrogenation is carried out in the presence of Raney nickel and an inorganic base to obtain Compound I.

[0037] Other reagents including sulfur dioxide gas (99%), carbon dioxide gas (99%), simulated flue gas (1000 ppm SO2, 15% CO2, 84.9% N2) can all be purchased from the market or can be prepared by the methods described in the present invention.

[0038] In the present invention, h represents hour; min represents minute; g represents gram; ml represents milliliter.

[0039] In the present invention, the absorption capacity is expressed as gSO2 / (g substrate), and the substrate is a 4-aminopiperidine derivative.

[0040] In the present invention, the definition of the desorption rate:

[0041]

[0042] Desorption rate iIt represents the percentage of the absorption capacity at the i-th regeneration to the absorption capacity at the first absorption, where i is an integer greater than or equal to 1.

[0043] Example 1

[0044] Synthesis of 4-aminopiperidine derivatives:

[0045]

[0046] where n = 1, 2, 4;

[0047] 82 g of aqueous formaldehyde solution was added to the reaction flask, the temperature was lowered to 0 - 5 °C, 208.3 mmol of Compound I was added, and the mixture was stirred for 30 min. Then, 105.5 g of formic acid was added dropwise. After the addition was completed, the temperature was raised to 60 °C and the reaction was carried out for 24 h. Hydrochloric acid was added until pH = 2, and the mixture was concentrated under reduced pressure. Sodium hydroxide solution was added to the residue until pH = 12, and then extracted with dichloromethane. After standing and separating, the organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the target Compound II.

[0048] When n = 1, the obtained Compound II was specifically 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol: 35 g, yield 97%. Figure 1 It is the 1H-NMR spectrum of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol, and the identification data are as follows: 1 H NMR(401MHz,DMSO)δ3.60–3.51(m,1H),3.46(t,J=6.4Hz,1H),2.86(d,J=11.0Hz,2H),2.42(dd,J=11.7,5.8Hz,1H),2.33(t,J=6.4Hz,1H),2.15(d,J=13.0Hz,6H),1.99(dd,J=9.3,5.7Hz,1H),1.89(t,J=11.0Hz,2H),1.68(d,J=11.0Hz,2H),1.33(q,J=11.9Hz,2H).

[0049] When n = 2, the obtained Compound II was specifically 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol: 33 g, yield 86%. Figure 2 It is the 1H-NMR spectrum of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol, and the identification data are as follows: 11H NMR (400 MHz, DMSO) δ 3.42 (dd, J = 13.4, 7.1 Hz, 2H), 2.90 (d, J = 11.5 Hz, 2H), 2.40–2.27 (m, 2H), 2.24–2.11 (m, 7H), 1.88 (t, J = 11.3 Hz, 2H), 1.74 (d, J = 12.0 Hz, 2H), 1.61–1.50 (m, 2H), 1.38 (dt, J = 20.8, 10.4 Hz, 2H).

[0050] When n = 4, the obtained compound II is specifically 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol: 32 g, yield 71%, Figure 3 It is the 1H-NMR spectrum of 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol, and the identification data are as follows: 1 1H NMR (400 MHz, DMSO) δ 3.43 (ddd, J = 19.3, 13.7, 6.3 Hz, 2H), 2.85 (d, J = 11.2 Hz, 2H), 2.25–2.18 (m, 2H), 2.16 (s, 6H), 2.04–1.92 (m, 1H), 1.80 (t, J = 11.4 Hz, 2H), 1.70 (d, J = 12.0 Hz, 2H), 1.59–1.21 (m, 8H).

[0051] Figure 4 It is the flow chart of the sulfur dioxide capture method provided by the present invention, including processes such as preparing an absorbent containing a 4-aminopiperidine derivative, adsorption, desorption, and recovery of the 4-aminopiperidine derivative. The following examples are carried out according to this process.

[0052] Example 2

[0053] 1. Prepare the absorbent: Add 2 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 18 g of sulfolane and stir to dissolve.

[0054] 2. Transfer the absorbent into a gas absorption bottle, then place the absorption bottle in a constant temperature water bath, and introduce sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 0.5 h.

[0055] 3. When the sulfur dioxide content in the absorbent is saturated, carry out desorption of the rich absorption liquid at -0.95 Mpa and 60 °C for 1 h, and the sulfur dioxide concentration in the absorbent decreases to become the lean liquid.

[0056] 4. Cool the lean absorption liquid and then carry out the operation of step 2. After absorption saturation, carry out desorption again.

[0057] 5. Repeat the above absorption and desorption processes. Finally, complete 5 absorptions and 4 desorptions, and the obtained results are listed in the following table.

[0058]

[0059] Among them, the substrate is 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0060] Example 3

[0061] 1. Prepare the absorbent: Add 2 g of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol to 8 g of sulfolane and stir to dissolve.

[0062] 2. Transfer the absorbent into a gas absorption bottle, then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 1.5 h.

[0063] 3. When the sulfur dioxide content in the absorbent is saturated, carry out desorption of the rich absorbent solution at -0.95 Mpa and 60 °C for 1 h, and the sulfur dioxide concentration in the absorbent decreases to become the lean solution.

[0064] 4. Cool down the lean absorbent solution and then perform the operation in step 2. After absorption saturation, perform desorption again.

[0065] 5. Repeat the above absorption and desorption processes. Finally, complete 5 absorptions and 4 desorptions, and the obtained results are listed in the following table.

[0066]

[0067] Among them, the substrate is 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol.

[0068] Example 4

[0069] 1. Prepare the absorbent: Add 2 g of 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol to 6 g of sulfolane and stir to dissolve.

[0070] 2. Transfer the absorbent into a gas absorption bottle, then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 3 h.

[0071] 3. When the sulfur dioxide content in the absorbent is saturated, carry out desorption of the rich absorbent solution at -0.95 Mpa and 60 °C for 1 h, and the sulfur dioxide concentration in the absorbent decreases to become the lean solution.

[0072] 4. Cool down the lean absorbent solution and then perform the operation in step 2. After absorption saturation, perform desorption again.

[0073] 5. Repeat the above absorption and desorption processes until 5 absorptions and 4 desorptions are finally completed. The obtained results are listed in the following table.

[0074]

[0075] Among them, the substrate is 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol.

[0076] Example 5

[0077] 1. Prepare the absorbent: Add 1.5 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 21.3 g of water, and then add 0.87 g of concentrated hydrochloric acid, and stir to dissolve.

[0078] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 0.5 h.

[0079] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at 20 °C with a N2 flow rate of 100 ml / min for desorption for 0.5 h, and the sulfur dioxide concentration in the absorbent decreases to become a lean solution.

[0080] 4. Perform the operation in step 2 on the lean absorbent solution again. After absorption saturation, perform desorption again.

[0081] 5. Repeat the above absorption and desorption processes until 5 absorptions and 4 desorptions are finally completed. The obtained results are listed in the following table.

[0082]

[0083] Among them, the substrate is 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0084] Example 6

[0085] 1. Prepare the absorbent: Add 1.56 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 8 g of water, and then add 0.44 g of sulfuric acid, and stir to dissolve.

[0086] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 0.5 h.

[0087] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at 20 °C with a N2 flow rate of 100 ml / min for desorption for 0.5 h, and the sulfur dioxide concentration in the absorbent decreases to become a lean solution.

[0088] 4. Re-perform the operation in Step 2 on the lean absorbent solution. After absorption saturation, perform desorption.

[0089] 5. Repeat the above absorption and desorption processes. Finally, complete 5 times of absorption and 4 times of desorption, and the obtained results are listed in the following table.

[0090]

[0091] Among them, the substrate is 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0092] Example 7

[0093] 1. Prepare the absorbent: Add 3 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 3 g of water, and then add 0.85 g of sulfuric acid, and stir to dissolve.

[0094] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 0.5 h.

[0095] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at 20 °C with a N2 flow rate of 100 ml / min for 0.5 h of desorption, and the sulfur dioxide concentration in the absorbent decreases and becomes the lean solution.

[0096] 4. Re-perform the operation in Step 2 on the lean absorbent solution. After absorption saturation, perform desorption.

[0097] 5. Repeat the above absorption and desorption processes. Finally, complete 5 times of absorption and 4 times of desorption, and the obtained results are listed in the following table.

[0098]

[0099] Among them, the substrate is 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0100] Example 8

[0101] 1. Prepare the absorbent: Add 1.75 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 8.75 g of water, and then add 0.3 g of phosphoric acid, and stir to dissolve.

[0102] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 0.5 h.

[0103] 3. When the sulfur dioxide content in the absorbent is saturated, introduce N2 into the rich absorbent solution at a temperature of 20°C and an N2 flow rate of 100 ml / min for 0.5 h of desorption, and the sulfur dioxide concentration in the absorbent decreases to become the lean solution.

[0104] 4. Perform the operation in step 2 on the lean absorbent solution again. After absorption saturation, perform desorption again.

[0105] 5. Repeat the above absorption and desorption processes. Finally, complete 5 absorptions and 4 desorptions, and the obtained results are listed in the following table.

[0106]

[0107] Among them, the substrate is 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol.

[0108] Example 9

[0109] 1. Prepare the absorbent: Add 2.12 g of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol to 8.5 g of water, and then add 0.36 g of formic acid, and stir to dissolve.

[0110] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Introduce sulfur dioxide at 20°C with a flow rate of 100 ml / min. The absorption time is 2.5 h.

[0111] 3. When the sulfur dioxide content in the absorbent is saturated, introduce N2 into the rich absorbent solution at a temperature of 20°C and an N2 flow rate of 100 ml / min for 0.5 h of desorption, and the sulfur dioxide concentration in the absorbent decreases to become the lean solution.

[0112] 4. Perform the operation in step 2 on the lean absorbent solution again. After absorption saturation, perform desorption again.

[0113] 5. Repeat the above absorption and desorption processes. Finally, complete 5 absorptions and 4 desorptions, and the obtained results are listed in the following table.

[0114]

[0115] Among them, the substrate is 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol.

[0116] Example 10

[0117] 1. Prepare the absorbent: Add 1.59 g of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol to 14.3 g of water, and then add 0.51 g of acetic acid, and stir to dissolve.

[0118] 2. Transfer the absorbent into a gas absorption flask, then place the absorption flask in a constant temperature water bath. Pass sulfur dioxide at 60 °C with a flow rate of 100 ml / min. The absorption time is 1.5 h.

[0119] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at a temperature of 20 °C with a N2 flow rate of 100 ml / min for desorption for 0.5 h, and the sulfur dioxide concentration in the absorbent decreases to become a lean solution.

[0120] 4. Perform the operation in step 2 on the lean absorbent again, and perform desorption after absorption saturation.

[0121] 5. Repeat the above absorption and desorption processes, and finally complete 5 absorptions and 4 desorptions. The obtained results are listed in the following table.

[0122]

[0123] Among them, the substrate is 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol.

[0124] Example 11

[0125] 1. Prepare the absorbent: Add 1.76 g of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol to 8.8 g of water, and then add 0.26 g of lactic acid, and stir to dissolve.

[0126] 2. Transfer the absorbent into a gas absorption flask, then place the absorption flask in a constant temperature water bath. Pass sulfur dioxide at 40 °C with a flow rate of 100 ml / min. The absorption time is 2.5 h.

[0127] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at a temperature of 20 °C with a N2 flow rate of 100 ml / min for desorption for 0.5 h, and the sulfur dioxide concentration in the absorbent decreases to become a lean solution.

[0128] 4. Perform the operation in step 2 on the lean absorbent again, and perform desorption after absorption saturation.

[0129] 5. Repeat the above absorption and desorption processes, and finally complete 5 absorptions and 4 desorptions. The obtained results are listed in the following table.

[0130]

[0131] Among them, the substrate is 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol.

[0132] Example 12

[0133] 1. Preparation of absorbent: Add 1.94 g of 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol to 15.5 g of water, and then add 0.7 g of malic acid, and stir to dissolve.

[0134] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 1.5 h.

[0135] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at 20 °C with an N2 flow rate of 100 ml / min for desorption for 0.5 h, and the sulfur dioxide concentration in the absorbent decreases to become a lean solution.

[0136] 4. Perform the operation in step 2 on the lean absorbent solution again, and perform desorption after absorption saturation.

[0137] 5. Repeat the above absorption and desorption processes, and finally complete 5 absorptions and 4 desorptions. The obtained results are listed in the following table.

[0138]

[0139] Among them, the substrate is 3-(4-(dimethylamino)piperidin-1-yl)propan-1-ol.

[0140] Example 13

[0141] 1. Preparation of absorbent: Add 2.4 g of 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol to 12 g of water, and then add 0.72 g of citric acid, and stir to dissolve.

[0142] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 3 h.

[0143] 3. When the sulfur dioxide content in the absorbent is saturated, pass 110 °C steam into the rich absorbent solution with a steam flow rate of 100 ml / min for desorption for 20 min, and the sulfur dioxide concentration in the absorbent decreases to become a lean solution.

[0144] 4. Perform the operation in step 2 on the lean absorbent solution again, and perform desorption after absorption saturation.

[0145] 5. Repeat the above absorption and desorption processes, and finally complete 5 absorptions and 4 desorptions. The obtained results are listed in the following table.

[0146]

[0147] Among them, the substrate is 5-(4-(dimethylamino)piperidin-1-yl)pentan-1-ol.

[0148] Example 14

[0149] 1. Prepare the absorbent: Add 1.56 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 8 g of water, and then add 0.44 g of sulfuric acid, and stir to dissolve.

[0150] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass the simulated flue gas at 20 °C with a flow rate of 100 ml / min. The absorption time is 1 h.

[0151] 3. Weigh and calculate the absorption capacity to be 86 mg SO2 / g of the substrate.

[0152] Comparative Example 1

[0153] 1. Prepare the absorbent: Add 2.2 g of 1,4-bis(2-hydroxyethyl)piperazine to 8.8 g of water, and then add 0.62 g of sulfuric acid, and stir to dissolve.

[0154] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass sulfur dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 1 h.

[0155] 3. When the sulfur dioxide content in the absorbent is saturated, pass N2 into the rich absorbent solution at 20 °C with an N2 flow rate of 100 ml / min for desorption for 0.5 h, and the sulfur dioxide concentration in the absorbent decreases and becomes the lean solution.

[0156] 4. Perform the operation in step 2 on the lean absorbent solution again, and perform desorption after absorption saturation.

[0157] 5. Repeat the above absorption and desorption processes, and finally complete 5 absorptions and 4 desorptions. The obtained results are listed in the following table.

[0158]

[0159] Among them, the substrate is 1,4-bis(2-hydroxyethyl)piperazine.

[0160] Comparative Example 2

[0161] 1. Prepare the absorbent: Add 1.56 g of 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol to 7.8 g of water, and then add 0.44 g of sulfuric acid, and stir to dissolve.

[0162] 2. Transfer the absorbent into a gas absorption bottle, and then place the absorption bottle in a constant temperature water bath. Pass carbon dioxide at 20 °C with a flow rate of 100 ml / min. The absorption time is 0.5 h.

[0163] 3. Weigh the absorption flask. The weight gain due to carbon dioxide absorption is zero, indicating that the absorbent does not absorb carbon dioxide but has good selectivity for sulfur dioxide.

[0164] As can be seen from the above, the 4-aminopiperidine derivative provided by the present invention has good sulfur dioxide absorption capacity and cycling performance, and has good selectivity for carbon dioxide. Among them, by comparing Example 6 and Comparative Example 1, it can be seen that 2-(4-(dimethylamino)piperidin-1-yl)ethan-1-ol has a 16% higher first absorption capacity and an 11% higher fourth desorption rate than Comparative Example 1, 1,4-bis(2-hydroxyethyl)piperazine. The former has a larger absorption capacity and better cycling performance.

Claims

1. The use of 4-aminopiperidine derivatives in capturing sulfur dioxide in a gas stream, characterized in that: 4-aminopiperidine derivatives are used as sulfur dioxide scavengers. 4-aminopiperidine derivatives or their inorganic acid salts or organic acid salts are dissolved in a solvent to prepare a solution, and then sulfur dioxide gas or a gas containing sulfur dioxide is introduced, and the sulfur dioxide is absorbed by the solution.

2. The use according to claim 1, characterized in that: The general structural formula of the 4-aminopiperidine derivative is as follows: Among them, n=1,2,4.

3. The use according to claim 1, characterized in that: The 4-aminopiperidine derivatives are 2-(4-(dimethylamino)piperidin-1-yl)ethane-1-ol, 3-(4-(dimethylamino)piperidin-1-yl)propane-1-ol, and 5-(4-(dimethylamino)piperidin-1-yl)pentane-1-ol.

4. The use according to claim 1, characterized in that: The inorganic acid includes hydrochloric acid, sulfuric acid, and phosphoric acid; the organic acid includes formic acid, acetic acid, lactic acid, malic acid, and citric acid.

5. The use according to claim 1, characterized in that: The solvent is water and / or sulfolane.

6. The use according to claim 1, characterized in that: The mass ratio of the 4-aminopiperidine derivative to the solvent is 1:0.5-19.

7. The use according to claim 1, characterized in that: The molar ratio of the 4-aminopiperidine derivative to the inorganic acid or organic acid is 1:(0.2-4).

8. The use according to claim 1, characterized in that: The absorption temperature of sulfur dioxide is 20-60°C, and the absorption time is 0.5-3h.

9. The use according to claim 1, characterized in that: The sulfur dioxide can be desorbed by passing N2 or water vapor into the solution that has absorbed sulfur dioxide, or by heating at 60-80°C for 0.5-2h under vacuum conditions, thereby achieving the recycling regeneration of the capture agent 4-aminopiperidine derivative.

10. An absorbent for capturing sulfur dioxide, characterized in that: The invention comprises the 4-aminopiperidine derivatives according to claim 1 or their inorganic acid salts or organic acid salts.

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