Guanidino functionalized ionic liquid and preparation method and application thereof

文档序号：460860 发布日期：2021-12-31 浏览：31次中文

阅读说明：本技术 一种胍基功能化离子液体及其制备方法和应用 (Guanidino functionalized ionic liquid and preparation method and application thereof ) 是由毛金银耿泽宇许芸蒋滨键耿嘉潞李畅刘沛霖于 2021-10-25 设计创作，主要内容包括：本发明公开了一种胍基功能化离子液体及其制备方法和应用,该离子液体的阳离子为1,1,3,3-四甲基胍阳离子,阴离子为甲氧基乙酸阴离子或乙氧基乙酸阴离子；在无水乙醇中加入1,1,3,3-四甲基胍,冰浴环境下缓慢滴入甲氧基乙酸或乙氧基乙酸,搅拌反应后,旋蒸移去无水乙醇和水得到含微量水的离子液体初品,真空干燥后即可得到胍基功能化离子液体。本发明的含胍基的离子液体用于捕集二氧化硫时,具有吸收容量较高、可重复利用等优点,且可在低温无溶剂条件下促进SO-(2)的有效转化,可用作烟气脱硫的有效吸收剂及SO-(2)与环氧化合物的环加成反应的催化剂。(The invention discloses a guanidino functionalized ionic liquid, a preparation method and application thereof, wherein cations of the ionic liquid are 1,1,3, 3-tetramethylguanidine cations, and anions are methoxy acetic acid anions or ethoxy acetic acid anions; adding 1,1,3, 3-tetramethyl guanidine into absolute ethyl alcohol, slowly dropping methoxyacetic acid or ethoxyacetic acid under ice bath environment, stirringAfter stirring reaction, removing anhydrous ethanol and water by rotary evaporation to obtain an ionic liquid primary product containing a small amount of water, and drying in vacuum to obtain the guanidino functionalized ionic liquid. When the guanidino-containing ionic liquid is used for capturing sulfur dioxide, the guanidino-containing ionic liquid has the advantages of high absorption capacity, reusability and the like, and can promote SO under the condition of low temperature and no solvent 2 Can be used as an effective absorbent and SO for flue gas desulfurization 2 A catalyst for cycloaddition reaction with an epoxy compound.)

1. A guanidino functionalized ionic liquid, which is characterized in that: the cation of the ionic liquid is 1,1,3, 3-tetramethylguanidine cation, and the anion is methoxy acetic acid anion or ethoxy acetic acid anion.

2. The guanidino-functionalized ionic liquid of claim 1, characterized in that: the ionic liquid has the viscosity of 184.4-295.2 cP at 30 ℃ and the density of 0.96962-1.25312 g.cm^-3。

3. A process for the preparation of a guanidino-functionalized ionic liquid according to claim 1, characterized in that: adding 1,1,3, 3-tetramethylguanidine into absolute ethyl alcohol, slowly dropping methoxyacetic acid or ethoxyacetic acid under an ice bath condition, stirring for reaction, removing the absolute ethyl alcohol and water by rotary evaporation, and drying an ionic liquid primary product in vacuum to obtain a guanidino functionalized ionic liquid; the anion of the ionic liquid is methoxy acetate ion or ethoxy acetate ion.

4. The method for preparing a guanidino-functionalized ionic liquid according to claim 3, characterized in that: the molar ratio of the 1,1,3, 3-tetramethylguanidine cation to the methoxy acetate ion or ethoxy acetate anion is 1: 1.

5. use of the guanidino-functionalized ionic liquid of claim 1 as an absorbent in flue gas desulfurization treatment.

6. Use according to claim 5, characterized in that it comprises the following steps: absorbing SO by using the prepared ionic liquid at the temperature of 30-60 ℃ and under the pressure of 1-100 kPa₂A gas; then desorbing SO by a regeneration method at the temperature of 30-60 ℃ and under the pressure of 0.001-1 kPa₂And recovering the ionic liquid.

7. Use according to claim 6, characterized in that: the regeneration method is to remove SO absorbed by the ionic liquid by a decompression or heating method₂。

8. The guanidino-functionalized ionic liquid of claim 1 in SO₂Use as a catalyst in a cycloaddition reaction with an epoxy compound.

9. Use according to claim 8, characterized in that it comprises the following steps: firstly, the prepared ionic liquid is used as an absorbent to trap SO₂And then reacting the mixture with an epoxy compound for 1-5 hours at 40-45 ℃, and extracting the product with diethyl ether after the reaction is finished to respectively obtain a separated product and ionic liquid.

10. Use according to claim 8, characterized in that: the epoxy compound comprises any one of 1, 2-epoxybutane, epoxypropanol, epichlorohydrin, epoxypropane, 2-methyl epoxypropane, 1, 2-epoxycyclohexane, 2, 3-epoxypropyl methyl ether, styrene oxide and epoxypropyl phenyl ether.

Technical Field

The invention belongs to capture and conversion of sulfur dioxide, and particularly relates to a guanidino functionalized ionic liquid capable of efficiently capturing and converting sulfur dioxide and a preparation method thereof.

Background

SO₂Mainly derived from the combustion of fossil fuels worldwide, and mainly removed by Flue Gas Desulfurization (FGD) technology. The traditional flue gas desulfurization methods are limited to limestone washing, ammonia washing and organic amine aqueous solution absorption, but the methods cannot recycle byproducts and organic steam, and are easy to cause secondary pollution. In recent years, a variety of new and effective absorbents have been used to absorb and trap SO₂Such as novel metal organic frameworks, low co-melting solvents, ionic liquids, and the like. The ionic liquid as room temperature molten salt has the advantages of negligible volatility, designability, stability of physicochemical properties and the like, and can absorb SO₂The aspect presents great advantages.

Existing studies have shown that functionalized ionic liquids including hydroxylammonium, imidazole/pyridine, etc. are very potential smoke absorbers. Despite the advances made in capturing sulfur dioxide by ionic liquids, little research has been done on direct capture of sulfur dioxide by ionic liquids and conversion of epoxides. The ionic liquid reported to have high viscosity and block SO₂The mass transfer and absorption diffusion from the gas phase to the liquid phase absorbent cause the ionic liquid to react with SO₂Overall lower absorption capacity, showing effective but limited SO₂The absorption capacity. So as to functionalize the ionic liquidWhen the absorbent is used for flue gas desulfurization, more energy is required to be consumed in the desorption process to achieve recoverability, and the problem of sulfur dioxide gas storage is easily caused. Thus, the ionic liquid is captured and converted to SO₂Process coupling is critical to reducing energy requirements.

Disclosure of Invention

The purpose of the invention is as follows: the first purpose of the invention is to provide a method for mixing SO₂The high-absorption-capacity guanidino functionalized ionic liquid combines trapping and conversion; the second purpose of the invention is to provide a preparation method of the guanidino functionalized ionic liquid; the third purpose of the invention is to provide the application of the guanidino functionalized ionic liquid as an absorbent in flue gas desulfurization; the fourth purpose of the invention is to provide the guanidino functionalized ionic liquid in SO₂Use as a catalyst in a cycloaddition reaction with an epoxy compound.

The technical scheme is as follows: the cation of the guanidino functionalized ionic liquid is 1,1,3, 3-tetramethylguanidine cation, and the anion is methoxy acetate anion or ethoxy acetate anion.

Further, the ionic liquid has the viscosity of 184.4-295.2 cP at 30 ℃ and the density of 0.96962-1.25312 g.cm^-3。

The invention also further protects the preparation method of the guanidino functionalized ionic liquid, which comprises the steps of adding 1,1,3, 3-tetramethylguanidine into absolute ethyl alcohol, slowly dropping methoxyacetic acid or ethoxyacetic acid under an ice bath condition, stirring, reacting, removing absolute ethyl alcohol and water through rotary evaporation, and drying an initial product in vacuum to obtain the guanidino functionalized ionic liquid; the anionic liquid is methoxy acetate or ethoxy acetate.

Further, the molar ratio of the 1,1,3, 3-tetramethylguanidine cation to the methoxy acetic acid or ethoxy acetic acid anion is 1: 1.

the invention also protects the application of the guanidino functionalized ionic liquid as an absorbent in flue gas desulfurization treatment.

Further, the method comprises the following steps: under the conditions of 30-60 ℃ and 1-100 kPaSO is absorbed by prepared ionic liquid₂A gas; then desorbing SO by a regeneration method at the temperature of 30-60 ℃ and under the pressure of 0.001-1 kPa₂And recovering the ionic liquid.

The regeneration method is to remove SO absorbed by the ionic liquid by a decompression or heating method₂。

The invention also protects the guanidino functionalized ionic liquid in SO₂Use as a catalyst in a cycloaddition reaction with an epoxy compound.

Further, the method comprises the following steps: the prepared ionic liquid is used for trapping SO₂And then reacting the mixture with an epoxy compound for 1-5 hours at the temperature of 30-50 ℃, and extracting the product with diethyl ether after the reaction is finished to respectively obtain a separated product and regenerated ionic liquid.

Further, the epoxy compound includes any one of 1, 2-epoxybutane, epoxypropanol, epichlorohydrin, epoxypropane, 2-methylepoxypropane, 1, 2-epoxycyclohexane, 2, 3-epoxypropylmethyl ether, styrene oxide and epoxypropylphenyl ether.

In the ionic liquid, cations contain guanidyl, anions are organic acid radicals, and the ionic liquid is alkaline as a whole and can capture SO through chemical absorption and physical absorption₂And promoting SO at low temperature without solvent₂The epoxide is converted into the cyclic sulfite with value-added benefit. Guanidinium cation and SO in guanidinium functionalized ionic liquid₂Form strong hydrogen bond effect and can chemically trap SO in a mode of molar ratio of 1:1₂The organic acid radical anion part can be reversible to carboxylic acid to capture SO through hydrogen bond action₂In addition, the guanidino functionalized ionic liquid can physically dissolve SO₂. Therefore, the ionic liquid can be used as an effective absorbent for flue gas desulfurization and has higher absorption capacity. In addition, the ionic liquid can be used as SO due to the regeneration effect of the ionic liquid₂A catalyst generated by cycloaddition reaction of the cyclic sulfite and an epoxy compound, thereby preparing cyclic sulfite; the ionic liquid does not change in the reaction process, andcan promote SO₂The yield of the cyclic sulfite compound is improved.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: (1) the functionalized ionic liquid has low viscosity which is lower than 300Cp at 30 ℃, and is beneficial to SO treatment₂Absorption and trapping; (2) the functionalized ionic liquid of the invention is used for SO₂The absorption capacity of the catalyst is higher and can reach 2.26mol of SO₂Per mol of ILs; (3) the functionalized ionic liquid can promote SO at low temperature without any other solvent₂The cyclic oxide is converted into the cyclic sulfite with added value, and the cyclic sulfite can be recycled and has certain commercial value and potential.

Drawings

FIG. 1 shows SO absorption by ionic liquid according to the present invention₂Front and back infrared spectra;

FIG. 2 is a structural and mass spectrum of a transformed product of example 8 of the present invention;

FIG. 3 is a structural and mass spectrum of a transformed product of example 14 of the present invention;

FIG. 4 shows the structure and mass spectrum of the transformed product of example 15 of the present invention;

FIG. 5 shows the structure and mass spectrum of the transformed product of example 16 of the present invention;

FIG. 6 shows the structure and mass spectrum of the transformed product of example 17 of the present invention;

FIG. 7 is a structural and mass spectrum of a transformed product of example 18 of the present invention;

FIG. 8 is a structural and mass spectrum of a transformed product of example 19 according to the present invention;

FIG. 9 shows the structure and mass spectrum of the transformed product of example 20 of the present invention;

FIG. 10 is a structural and mass spectrum of a transformed product of example 21 of the present invention;

FIG. 11 is a graph showing the results of the test of repeating the absorption-desorption in example 7 of the present invention.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and examples.

Example 1

5.76g (0.05mol) of 1,1,3, 3-tetramethylguanidine are added to 50mL of absolute ethanol, dissolved in a 250mL flask, 4.50g (0.05mol) of methoxyacetic acid are slowly added dropwise in an ice-water bath, stirred, and after 24 hours of reaction, ethanol and water are removed by rotary evaporation, and the residue is a crude product. Then vacuum drying for at least 48h under 323.2K to obtain the ionic liquid 1,1,3, 3-tetramethyl guanidine methoxy acetate [ TMG ] [ MOAc ].

The chemical structural formula is as follows:

the prepared ionic liquid has the viscosity of 295.2cP and the density of 1.09623g.cm at 30 ℃ through detection^-3。

And (3) characterization results: [ TMG][MOAc]:¹H NMR(300MHz,CDCl₃)δ3.83-3.82(d,2H),3.69-3.66(dddd,J＝12.2,7.0,5.1,2.3Hz,1H),3.37–3.36(m,3H),2.98–2.97(m,12H),1.24-1.17(m,1H).¹³C NMR(75MHz,CDCl₃)δ175.2,162.2,72.6,58.2,57.1,39.5,18.2.HRMS(EI⁺)Calcd for[C₅H₁₄N₃](M⁺):116.11822,found 116.11833；HRMS(EI-)Calcd for[C₃H₅O₃](M^-):89.02442,found 89.02471.IR(ATR):3417.0,2942.2,2823.5,2137.2,1609.5,1453.1,1411.6,1411.6,1326.1,1288.5,1239.8,1197.5,1112.1,1065.7,1038.7,986.3,940.3,905.5,877.8,708.1.

Example 2

In a manner similar to example 1, 5.76g (0.05mol) of 1,1,3, 3-tetramethylguanidine were added to 50mL of anhydrous ethanol, dissolved in a 250mL flask, 5.21g (0.05mol) of ethoxyacetic acid were slowly added dropwise under an ice-water bath, stirred, and after 24 hours of reaction, ethanol and water were removed by rotary evaporation to give a crude product as a residue. Then dried for at least 48h under 323.2K in vacuum to obtain the ionic liquid 1,1,3, 3-tetramethyl guanidine ethoxy acetate [ TMG ] [ EOAc ].

The chemical structural formula is as follows:

the prepared ionic liquid has the viscosity of 184.4cP and the density of 1.06359g.cm at 30 ℃ through detection^-3。

And (3) characterization results:¹H NMR(300MHz,CDCl₃)δ3.88(d,J＝0.7Hz,2H),3.72-3.70(qd,J＝7.0,0.7Hz,1H),3.58-3.51(qd,J＝7.1,0.6Hz,2H),2.98(s,12H),1.25-1.18(tdd,J＝7.1,3.8,0.6Hz,4H).¹³C NMR(75MHz,CDCl₃)δ175.8,162.4,77.6,77.2,76.7,70.8,65.9,57.5,39.6,18.3,15.1.HRMS(EI⁺)Calcd for[C₅H₁₄N₃](M⁺):116.11822,found 116.11855；HRMS(EI^-)Calcd for[C₄H₇O₃](M^-):103.04007,found 103.04007.IR(ATR):3439.4,3176.1,2973.8,2933.5,2910.2,2879.7,2855.0,1603.1,1571.8,1445.1,1422.5,1411.0,1364.4,1319.1,1264.6,1244.7,1123.0,1066.4,1037.1,929.9,894.2,880.6,854.4,700.3,608.4.

example 3

1,1,3, 3-tetramethylguanylmethoxyacetate [ TMG ] synthesized in example 1 was weighed][MOAc]Placing 1g of the powder into an absorption tank, vacuumizing the absorption tank, and introducing SO into the absorption tank under the constant temperature of 30 DEG C₂Absorbing, and when the pressure in the absorption cell is kept balanced for 30min, indicating that the ionic liquid absorbs SO₂Saturation has been reached. After experiments, when SO is used₂SO at a partial pressure of 100kPa₂Has an absorption amount of 2.00mol SO₂/mol ILs(9.76mol SO₂/kg ILs)。

[TMG][MOAc]Absorption of SO₂The mechanism of (2) is as follows:

see FIG. 1, [ TMG][MOAc]Absorption of SO₂Front and back infrared spectra. Comparative absorption of SO₂Front and back spectra at 583.1 and 508.8cm^-1A new peak appeared due to S ═ O shear bending vibration at 957.9cm^-1A new peak occurs, which is the asymmetric stretching vibration of S ═ O. In [ TMG ]][MOAc]Absorption of SO₂The infrared spectrum of the product is 1732.2cm^-1And 1569.4cm^-1Two C ═ O and C ═ N vibrational peaks appear, indicating that small amounts of ILs react reversibly to give amines and acids. Results of FTIR and hypothetical [ TMG][MOAc]In SO₂The capture mechanism is consistent.

Example 4

1,1,3, 3-tetramethylguanethoxy acetate [ TMG ] synthesized in example 2 was accurately weighed][EOAc]Placing 1g of the powder into an absorption tank, vacuumizing the absorption tank, and introducing SO into the absorption tank under the constant temperature of 30 DEG C₂Absorbing, and when the pressure in the absorption cell is kept balanced for 30min, indicating that the ionic liquid absorbs SO₂Saturation has been reached. After experiments, when SO is used₂SO at a partial pressure of 100kPa₂Has an absorption amount of 2.26mol SO₂/mol ILs(10.33mol SO₂/kg ILs). Absorption of SO₂The mechanism of (3) is similar to that of example 3.

Example 5

1,1,3, 3-tetramethylguanidineacetate [ TMG ] [ Ac ] was synthesized by replacing methoxyacetic acid with acetic acid according to the preparation method of example 1.

Synthesizing 1,1,3, 3-tetramethylguanidine acetate [ TMG ]][Ac]Placing 1g of the powder into an absorption tank, vacuumizing the absorption tank, and introducing SO into the absorption tank under the constant temperature of 30 DEG C₂Absorbing, and when the pressure in the absorption cell is kept balanced for 30min, indicating that the ionic liquid absorbs SO₂Saturation has been reached. After experiments, when SO is used₂SO at a partial pressure of 100kPa₂Has an absorption amount of 1.82mol SO₂/mol ILs(10.42mol SO₂/kg ILs)。

Example 6

Synthesis of 1,1,3, 3-tetramethylguanylfluoroborate [ TMG ] according to the preparation method of example 1, substituting methoxyacetic acid for fluoroboric acid][BF₄]。

Synthesizing 1,1,3, 3-tetramethylGuanidine fluoroborate [ TMG ]][BF₄]Placing 1g of the powder into an absorption tank, vacuumizing the absorption tank, and introducing SO into the absorption tank under the constant temperature of 30 DEG C₂Absorbing, and when the pressure in the absorption cell is kept balanced for 30min, indicating that the ionic liquid absorbs SO₂Saturation has been reached. After experiments, when SO is used₂SO at a partial pressure of 100kPa₂Has an absorption amount of 0.58mol SO₂/mol ILs(3.60mol SO₂/kg ILs)。

By SO of example 5 and example 6₂The absorption data show that when the anion of the ionic liquid is replaced by other organic acid, the SO of the obtained ionic liquid₂The significant decrease in the amount of absorption indicates the SO of the present invention₂The absorption mechanism is the result of the combined action of anions and cations.

Example 7

The SO is absorbed in example 3₂The ion liquid after equilibrium was desorbed at 30 ℃ and a pressure of 0.01kPa for 1 hour, the operation of example 3 was repeated with the desorbed ion liquid, and the absorption equilibrium was again reached after 1 hour, and absorption-desorption was repeated four times, as shown in FIG. 11, [ TMG ]][MOAc]Absorption of SO₂The amount is reduced by 11% of the first absorption maximum. Will [ TMG ]][MOAc]For the catalytic reaction of epoxy compound, after the reaction is finished, some ether is added into the reaction system, the product is collected from the upper organic layer, and the [ TMG ] can be recovered from the lower layer][MOAc]Recycled TMG][MOAc]Without any special treatment. [ TMG][MOAc]Can be repeatedly used for 5 times without obvious loss of catalytic activity. Visible [ TMG ]][MOAc]After regeneration, SO is trapped₂The reduction in capacity has no effect on catalytic activity. Thus, [ TMG ]][MOAc]Is a good cycloaddition solvent and catalyst.

Example 8

1,1,3, 3-tetramethylguanylmethoxyacetic acid [ TMG ] synthesized in example 1 was weighed][MOAc]0.05g was added to a 10mL Schlenk flask and SO was trapped at room temperature₂. The air in the bottle is pumped out by a vacuum pump, and then a needle is inserted into the bottle cap of the bottle for SO₂Bubbling, absorption rate about 8 ml/min, after 10 min 5.75mmol (0.5ml) of 1, 2-epoxybutane was injected into Schlenk's flask using a syringeAnd (5) performing reaction for 5 hours at 40 ℃ after sealing the flask. After the reaction is finished, after the schlenk bottle is cooled, the mixture is extracted by ethyl ether for three times, the product exists in the ethyl ether phase, and the separated ionic liquid can be regenerated and reused. The extracted product is measured by a gas chromatography-mass spectrometer by taking dodecane as an internal standard, and the gas yield of the converted 1, 2-epoxybutane can reach more than 99 percent through detection.