WO2016197439A1 - Catalytic system and method for preparing ethylene carbonate derivative by reaction of carbon dioxide and ethylene oxide derivative under extremely mild conditions - Google Patents

Abstract

An imidazole ionic liquid-ZnX2/base catalytic system and a method for catalytic preparation of an ethylene carbonate derivative with same. The catalytic system is composed of three ingredients, an imidazole ionic liquid, ZnX2 and a base and can catalyze a cycloaddition reaction of carbon dioxide and an ethylene oxide derivative under conditions of 0.5-1 atm., 15°C-35°C and a green solvent. The amounts of ZnX2 and the base are both 0.5%-5% of the molar amount of the ethylene oxide derivative, and the amount of the imidazole ionic liquid is 1-3 times the molar amount of the ethylene oxide derivative. The synthetic method has the characteristics of strictly mild reaction conditions, high catalytic activity, a single product, a high reaction yield, a reusable catalyst, a simple product purification operation and the like.

Description

Catalytic system for preparing ethylene carbonate derivative by reacting carbon dioxide with ethylene oxide derivative under extremely mild conditions and preparation method thereof Technical field

The invention relates to a catalytic system and a catalytic method for preparing an ethylene carbonate derivative by cycloaddition of an ethylene oxide derivative and carbon dioxide, in particular an imidazole ionic liquids-imidazole ionic liquids- ZnX ₂ /base) catalytic system and a method for the catalytic preparation thereof for ethylene carbonate derivatives.

Background technique

Carbon dioxide (CO ₂ ) is one of the most widely distributed, most abundant and cheapest carbon resources on the planet. It is estimated that there are about 10 ¹⁶ tons of carbon in the form of CO ₂ and carbonate. In addition, CO ₂ has many advantages such as stable nature, non-toxicity, non-corrosiveness, flame retardancy, and easy handling. The use of a carbon atom (ie C1) to replace petrochemical resources with limited reserves and non-renewable resources, and the use of chemical conversion to obtain useful compounds has always been one of the most concerned green chemistry topics, with important application value and theoretical significance. .

At present, the chemical utilization of CO ₂ has begun to take shape, and nearly 110 million tons of CO ₂ are chemically fixed each year. The synthesis of urea is the largest chemical method for the fixation of CO ₂ , which consumes more than 70 million tons of CO ₂ per year; followed by inorganic carbonates, which amount to 30 million tons per year; and the reduction of CO _{2 by} hydrogenation to 6 million tons. In addition, more than 20,000 tons of CO _{2 are} used each year for the synthesis of pharmaceutical intermediates salicylic acid and butyl acrylate. Although the chemical conversion method of CO ₂ has been applied in industrial production, it is not enough to solve the greenhouse effect caused by the increasingly severe CO ₂ emission due to the limitation of production scale and single method. It is an urgent problem for chemists to study the new CO ₂ chemical conversion method and increase the CO ₂ chemical conversion product in order to increase the conversion and utilization scale of CO ₂ .

CO ₂ can be reacted with ethylene oxide to form ethylene carbonate, in which CO ₂ is 100% utilized without the production of by-products. The obtained ethylene carbonate derivative is not only a kind of excellent aprotic solvent, electrolyte, fuel additive, but also can be used as a reaction intermediate for the synthesis of some fine chemical products, engineering plastics and drug synthesis. Therefore, the exploration in this aspect has important practical significance for the conversion and utilization of CO ₂ and is one of the hot research fields. After more than a decade of development, it has been found that a large number of catalysts can catalyze the reaction of CO ₂ with ethylene oxide. These catalysts include alkali metal salts, metal oxides, molecular sieves, montmorillonite, polyoxometallates, organotins, organic phosphonium, quaternary ammonium salt ionic liquids, imidazole type ionic liquids, transition metal compounds, and the like. However, these catalytic systems have some common disadvantages: such as high CO ₂ pressure (2-10 MPa), high temperature (40-120 ° C), long reaction time (several days), and adaptation to substrates - narrow In particular, it does not work for ethylene oxide with large steric hindrance, large catalyst loading, use of organic solvents, low yield, and non-recyclability of catalysts (X. Liu, C. Cao, Y. Li, P. Guan, L. Yang, Y. Shi, Synlett, 2012, 23, 1343-1348. MJAjitha, CHSuresh, Tetrahedron Lett., 2011, 52, 5403-5406.).

In 2012, Changsheng Cao and Yanhui Shi research group reported the use of NHC carbene precursor / ZnBr ₂ and K ₂ CO ₃ as a catalytic system to carry out the reaction of CO ₂ with ethylene oxide to form ethylene carbonate derivatives. The reaction can use 0.1 MPa (i.e., 1 atm) of CO ₂ , and the yield is high, but the reaction still needs to be carried out at 80 ° C, and DMSO is used as a solvent (X. Liu, C. Cao, Y. Li, P. Guan, L. Yang, Y. Shi, Synlett, 2012, 23, 1343-1348.).

The use of organic solvents not only increases the cost of the reaction, but also poses certain difficulties for the post-treatment of the product, and is potentially dangerous to the environment, and the ionic liquid is composed of positively charged and negatively charged ions. It is non-toxic, non-flammable, easy to prepare, and can be used as a solvent or catalyst or catalyst active carrier for many chemical reactions . It exhibits good solubility for a large number of inorganic and organic substances, and has the dual functions of solvent and catalyst. Therefore, it is necessary and important to study the use of ionic liquids instead of organic solvents for the above reactions.

In 2003, the HSKim team used the ionic liquid-ZnBr ₂ system to catalyze the reaction of CO ₂ with ethylene oxide. The advantage is that the use of the organic solvent is omitted and the reaction time is shortened (1 h), but the disadvantage is that the reaction pressure is too large, and 2.1 to 3.5 MPa of CO ₂ is required, and the reaction is carried out at 100 ° C (HSKim, JJ Kim, H. Kim, HGJang, J. Catalysis, 2003, 220, 44-46).

In view of the above, it is highly desirable to develop a catalytic system which allows CO ₂ and ethylene oxide derivatives to form ethylene carbonate derivatives under very mild conditions. This application invents a simple imidazole ionic liquids-ZnX ₂ /base catalytic system to achieve a) green solvent (ie imidazole-type ionic liquid, eliminating the use of organic solvents) )) b) Catalyst (ie imidazole-type ionic liquid) is easy to prepare, non-toxic, recyclable, c) low in cocatalyst loading (0.5-5 mol% ZnX ₂ and base), d) room temperature range (15-35 ° C) Under the conditions, e) a short time (1-5h), f) 0.05-0.1MPa (ie 0.5-1 atm) reaction of CO ₂ with an ethylene oxide derivative. In addition, g) the system has a wide range of adaptation to substrates, especially for ethylene oxide with high steric hindrance, which has rarely been reported in previous studies. The yield of the reaction is high. The yield of the reaction is above 90% as carried out under the preferred experimental conditions.

Summary of the invention

It is an object of the present invention to provide an imidazole ionic liquids-ZnX ₂ /base catalytic system and a process for the catalytic preparation thereof.

Imidazole-type ionic liquid-zinc halide/base catalyst system consisting of imidazole-type ionic liquid (as catalyst and green solvent), zinc halide and alkali. It can be in the range of 0.5-1 atm and room temperature (15-35 °C). Under the conditions, the cycloaddition reaction of carbon dioxide with an ethylene oxide derivative is catalyzed.

The imidazole-type ionic liquid is a salt of 1,3-dialkyl-substituted imidazole or imidazole such as chlorine, bromine or iodine, and the structural formula is represented by the following formulas (1) and (2):

n, m = 1, 2, 3, ... a positive integer;

Q = Cl, Br, I, OH, OAc, OTs, OTf, NO ₃ , BF ₄ , PF ₆ ;

Y = H, F, Cl, Br, I, OH, NH ₂ , SH, CN.

The zinc halide is ZnCl ₂ , ZnBr ₂ or ZnI ₂ .

The base is an inorganic base or an organic base.

The inorganic base is NaCO ₃ , K ₂ CO ₃ , Ce ₂ CO ₃ , NaHCO ₃ , NaOAc, etc.; the organic base is H ₂ NEt, HNEt ₂ , NEt ₃ , HN(i-Pr) ₂ , H ₂ N(t-Bu), HNCy ₂ , NMeCy ₂ , H ₂ NCH ₂ CH ₂ NH ₂ , H ₂ N(CH ₂ ) ₆ NH ₂ , PhNH ₂ , (p-CH ₃ )C ₆ H ₄ NH ₂ , NMe ₂ Ph, pyridine, piperididine, 1-methylpiperidine, DBU, DBN, and the like.

Imidazole-type ionic liquid-zinc halide/alkali system catalyzed preparation of ethylene carbonate derivatives, imidazole-type ionic liquid-zinc halide/base catalyst system, imidazole-type ionic liquid, zinc halide and alkali are mixed in proportion, and then introduced into CO ₂ or with a CO ₂ balloon, ethylene oxide or ethylene oxide derivative, and reacted at room temperature (15-35 ° C) for 1-5 h, the corresponding ethylene carbonate derivative can be obtained.

The amount of the zinc halide and the base is 0.5 to 5% by mole of the ethylene oxide derivative, and the amount of the imidazole-type ionic liquid is 1 to 3 times the molar amount of the ethylene oxide derivative.

The CO ₂ pressure is 0.05-0.1 MPa (i.e., 0.5-1 atm).

Further preferably, the ethylene oxide derivative (1 eq.) is a reaction substrate, 1-butyl-3-methylimidazolium salt ([Bmim]Br) (2 eq.) is used as the imidazole-type ionic liquid, and the zinc halide is ZnBr. ₂ (3 mol%), the base was reacted with K ₂ CO ₃ (3 mol%) at 25 ° C for ₂ h under a 1 atm CO ₂ atmosphere. The yield of the reaction at this time was all above 90%.

The oxirane derivative may be any one of the compounds represented by the following formula (3), formula (4), or formula (5);

Wherein: R ¹ , R ² , R ³ , R ⁴ =H, a saturated and unsaturated hydrocarbon group, Ar, (CH ₂ ) _n Cl, (CH ₂ ) _n Br, (CH ₂ ) _n OH, (CH ₂ ) _n NH ₂ , (CH ₂ ) _n OR, (CH ₂ ) _n OAr, (CH ₂ ) _n OCOR, (CH ₂ ) _n NHR, (CH ₂ ) _n NR ₂ , (CH ₂ ) _n OCOAr, (CH _{2 n} O(CH ₂ ) _m R, (CH ₂ ) _n O(CH ₂ ) _m Ar, COOR, COOAr, NR ₂ , NHR, SR;

n, m = 1, 2, 3, ... a positive integer;

Z=CH ₂ , NH, O, S, S=O, SO ₂ ;

R is a saturated, unsaturated hydrocarbon group, CN;

Ar is a substituted or unsubstituted aromatic group;

Substituents on the aromatic group include F, Cl, Br, I, OH, OTs, CN, NO ₂ , CHO, COOH, OSO ₃ H, alkoxy, ester, saturated and unsaturated hydrocarbon groups;

The aromatic compound corresponding to the aromatic group (Ar) includes: 1) a five-membered ring: furan, thiophene, pyrrole, thiazole, pyrazole, imidazole; 2) six-membered ring: pyridine, pyridazine, pyrimidine, pyrazine, pyran; 3) fused heterocyclic ring: i) naphthalene, quinoline, isoquinoline, benzopyran, salt, ii) hydrazine, acridine, iii) hydrazine, hydrazine, hydrazine, isoindole, hydrazine, Iv) 芴, carbazole.

Beneficial effects:

The imidazole-type ionic liquids-ZnX ₂ /base catalytic system provided by the invention realizes a) a green solvent (ie, an imidazole-type ionic liquid, eliminating the use of an organic solvent), b) Catalyst (ie imidazole-type ionic liquid) is easy to prepare, non-toxic, recyclable, c) low cocatalyst loading (0.5-5 mol% ZnX ₂ and base), d) room temperature range (15-35 ° C), e The reaction of CO ₂ with an ethylene oxide derivative in a short time (1-5 h), f) 0.05-0.1 MPa (i.e., 0.5-1 atm). In addition, g) the system has a wide range of adaptation to substrates, especially for oxime-resistant ethylene oxide, which has rarely been reported in previous studies. h) The yield of the reaction is high. The yield of the reaction is above 90% as carried out under the preferred experimental conditions.

detailed description

The invention is further described in detail below with reference to the specific embodiments, but these examples are merely exemplary, and the scope of the invention is not limited to the embodiments described below. A person skilled in the art can easily make various substitutions, modifications, and alterations to the present invention, which are within the scope of the present invention.

Example 1

Imidazole ionic liquids-ZnX ₂ /base catalytic system consisting of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) (imidazole-type ionic liquid), zinc bromide and potassium carbonate As a [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ system.

The [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ system catalyzes the cycloaddition reaction of CO ₂ and epichlorohydrin to prepare the corresponding ethylene carbonate derivative. The chemical reaction formula is:

experiment procedure:

0.0208 g (0.15 mmol) of potassium carbonate, 0.0338 g (0.15 mmol) of zinc bromide, and 2.1913 g (10 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. Add the stirrer, plug the anti-seal seal, then put the test tube on the vacuum line, then connect the balloon with high-purity CO ₂ and fill the test tube with CO ₂ and use a syringe to test the tube. 0.35 mL (5 mmol) of epichlorohydrin was injected and reacted at room temperature for 2 h. After the reaction was stopped, 25 mL of deionized water was added, and the mixture was extracted with ethyl acetate (3×10 mL), dried over anhydrous magnesium sulfate, and the combined filtrate was evaporated on a rotary evaporator to obtain a crude product, which was purified by column chromatography. As dichloromethane, the obtained yellow liquid is the target product. The yield was 94%.

Product characterization data: Molecular Formula C ₄ H ₅ ClO ₃ . ¹ H NMR (400 MHz, CDCl ₃ ) d: 5.01-4.95 (m, 1H), 4.57 (t, J = 8.8 Hz, 1H), 4.37 (dd, J ₁ = 8.8 Hz, J ₂ = 5.6 Hz, 1H), 3.80 (dd, J ₁ = 12.0 Hz, J ₂ = 4.8 Hz, 1H), 3.70 (dd, J ₁ = 12.4 Hz, J ₂ = 3.6 Hz, 1H) ¹³ C NMR (100 MHz, CDCl ₃ ) d: 154.5, 74.5, 66.9, 44.1. IR (KBr, cm ^-1 ): 1801 (?CO).

Example 2

[Bmim]Br-ZnBr ₂ /K ₂ CO ₃ system catalyzes the cycloaddition reaction of CO ₂ and racemic (trans)-2,3-butylene oxide to prepare the corresponding ethylene carbonate derivative, chemistry The reaction formula is:

experiment procedure:

0.0208 g (0.15 mmol) of potassium carbonate, 0.0338 g (0.15 mmol) of zinc bromide, and 2.1913 g (10 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. Add a stirrer, plug the anti-seal seal, and then vacuum the test tube on the vacuum line, then attach a balloon filled with high-purity CO _{2 to} the branch tube and fill the test tube with CO ₂ and use a syringe to test the tube. 0.3606 g (5 mmol) of racemic (trans)-2,3-butylene oxide was injected and reacted at room temperature for 2 h. After the reaction was stopped, 25 mL of deionized water was added, and the mixture was extracted with ethyl acetate (3×10 mL), dried over anhydrous magnesium sulfate, and the combined filtrate was evaporated on a rotary evaporator to obtain a crude product, which was purified by column chromatography. As dichloromethane, the colorless liquid obtained is the target product. The yield was 93%.

The product characterizing data: molecular formula ^{_{C 5 H 8 O 3 1 H}} NMR (400MHz, CDCl 3) d: 4.32 (m, 2H), 1.44 (m, 6H) 13 C NMR (100MHz, CDCl 3) d:. 154.6, 80.0, 18.5. IR (KBr):? =1785cm ^-1 (C=O).

Example 3

[Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system, catalyzed cycloaddition reaction of CO ₂ and furan methyl glycidyl ether to prepare corresponding ethylene carbonate derivatives, the chemical reaction formula is:

experiment procedure:

0.0208 g (0.15 mmol) of potassium carbonate, 0.0338 g (0.15 mmol) of zinc bromide, and 2.1913 g (10 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. Add a stirrer, plug the anti-seal seal, and then vacuum the test tube on the vacuum line, then attach a balloon filled with high-purity CO _{2 to} the branch tube and fill the test tube with CO ₂ and use a syringe to test the tube. 0.7710 g (5 mmol) of furan methyl glycidyl ether was injected and reacted at room temperature for 2 h. After the reaction was stopped, 25 mL of deionized water was added, and the mixture was extracted with ethyl acetate (3×10 mL), dried over anhydrous magnesium sulfate, and the combined filtrate was evaporated on a rotary evaporator to obtain a crude product, which was purified by column chromatography. As methylene chloride), a yellow liquid is obtained as the target product. The yield was 97%.

Product characterization data: Molecular Formula C ₉ H ₁₀ O ₅ . ¹ H NMR (400 MHz, CDCl ₃ ) d: 7.40 (t, ³ J _HH = 1.2 Hz, 1H), 6.34 (d, ³ J _HH = 1.2 Hz, 2H) , 4.81-4.75 (m, 1H), 4.52 (dd, ² J _HH = 24.8 Hz and ³ J _HH = 13.2 Hz, 2H), 4.45 (dd, ² J _HH = 7.2 Hz and ³ J _HH = 7.2 Hz, 1H ), 4.31 (dd, ² J _HH = 8.4 Hz and ³ J _HH = 6.4 Hz, 1H), 3.69 (dd, ² J _HH = 11.2 Hz and ³ J _HH = 4.0 Hz, 1H), 3.61 (dd, ² J) _HH = 11.2 Hz and ³ J _HH = 4.0 Hz, 1H). ¹³ C NMR (100 MHz, CDCl ₃ ) d: 155.0, 150.7, 143.2, 110.5, 110.2, 75.0, 68.5, 66.3, 65.3. IR (KBr):? ^{= 1793cm -1 (C = O)} .HRMS (ESI) m / z: Calcd.For [MH] - C 9 H 9 O 5: 197.0449; found: 197.0446.

Example 4

[Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system, catalyzing the cycloaddition reaction of CO ₂ and benzoic acid (oxiranylmethyl) ester to prepare the corresponding ethylene carbonate derivative, the chemical reaction formula is :

experiment procedure:

0.0208 g (0.15 mmol) of potassium carbonate, 0.0338 g (0.15 mmol) of zinc bromide, and 2.1913 g (10 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. Add a stirrer, plug the anti-seal seal, and then vacuum the test tube on the vacuum line, then attach a balloon filled with high-purity CO _{2 to} the branch tube and fill the test tube with CO ₂ and use a syringe to test the tube. 1.1110 g (5 mmol) of benzoic acid (oxiranylmethyl) ester was injected and reacted at room temperature for 2 h. After the reaction was stopped, 25 mL of deionized water was added, and the mixture was extracted with ethyl acetate (3×10 mL), dried over anhydrous magnesium sulfate, and the combined filtrate was evaporated on a rotary evaporator to obtain a crude product, which was purified by column chromatography. As a dichloromethane, a white solid is obtained as the desired product. The yield was 98%.

Product characterization data: Molecular Formula C ₁₁ H ₁₀ O ₅ . ¹ H NMR (400 MHz, CDCl ₃ ) d: 8.01 (m, 2H), 7.58 (m, 1H), 7.45 (m, 2H), 5.08-5.03 (m, 1H), 4.62 (dd, ² J _HH = 8.4 Hz and ³ J _HH = 8.4 Hz, 1H), 4.58 (dd, ² J _HH = 11.6 Hz and ³ J _HH = 2.0 Hz, 1H), 4.49 (dd, ² J _HH = 12.8 Hz and ³ J _HH = 4.0 Hz, 1H), 4.42 (dd, ² J _HH = 8.8 Hz and ³ J _HH = 5.6 Hz, 1H). ¹³ C NMR (100 MHz, CDCl ₃ )d: 166.0 ( C=O), 154.7, 133.8, 129.8, 128.8, 128.7, 74.0, 66.2, 63.7. IR (KBr):? =1786cm ^-1 (C=O).

Example 5

[Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system, catalyzing the cycloaddition reaction of CO ₂ and 3,6-dioxo-bicyclo[3.1.0]hexane to prepare the corresponding ethylene carbonate derivative, The chemical reaction formula is:

experiment procedure:

0.0208 g (0.15 mmol) of potassium carbonate, 0.0338 g (0.15 mmol) of zinc bromide, and 2.1913 g (10 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. Add a stirrer, plug the anti-seal seal, and then vacuum the test tube on the vacuum line, then attach a balloon filled with high-purity CO _{2 to} the branch tube and fill the test tube with CO ₂ and use a syringe to test the tube. 0.6505 g (5 mmol) of 3,6-dioxo-bicyclo[3.1.0]hexane was injected and reacted at room temperature for 2 h. After the reaction was stopped, 25 mL of deionized water was added, and the mixture was extracted with ethyl acetate (3×10 mL), dried over anhydrous magnesium sulfate, and the combined filtrate was evaporated on a rotary evaporator to obtain a crude product, which was purified by column chromatography. As a dichloromethane, a white solid is obtained as the desired product. The yield was 91%.

The product characterizing data: molecular formula ^{_{C 5 H 6 O 4 1 H}} NMR (400MHz, CDCl 3) d: 5.20 (m, 2H), 4.26 (d, 3 J HH = 12.0Hz, 2H), 3.56 (m, 2H) ¹³ C NMR (100 MHz, CDCl ₃ )d: 154.5, 80.1, 73.1. IR (KBr):? =1794cm ^-1 (C=O).

Example 6

The [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ system catalyzes the cycloaddition reaction of CO ₂ and 1,2-epoxycyclohexane to prepare a corresponding ethylene carbonate derivative. The chemical reaction formula is:

experiment procedure:

0.0208 g (0.15 mmol) of potassium carbonate, 0.0338 g (0.15 mmol) of zinc bromide, and 2.1913 g (10 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. Add a stirrer, plug the anti-seal seal, and then vacuum the test tube on the vacuum line, then attach a balloon filled with high-purity CO _{2 to} the branch tube and fill the test tube with CO ₂ and use a syringe to test the tube. 0.4908 g (5 mmol) of 1,2-epoxycyclohexane was injected and reacted at room temperature for 2 h. After the reaction was stopped, 25 mL of deionized water was added, and the mixture was extracted with ethyl acetate (3×10 mL), dried over anhydrous magnesium sulfate, and the combined filtrate was evaporated on a rotary evaporator to obtain a crude product, which was purified by column chromatography. As dichloromethane, the colorless liquid obtained is the target product. The yield was 91%.

Product characterization data: Molecular Formula C ₇ H ₁₀ O ₃ . ¹ H NMR (400 MHz, CDCl ₃ ) d: 4.70-4.65 (m, 2H), 1.91-1.87 (m, 4H), 1.66-1.57 (m, 2H), 1.46-1.38 (m, 2H). ¹³ C NMR (100 MHz, CDCl ₃ ) d: 155.5, 75.9, 26.9, 19.3, IR (KBr, cm ^-1 ): 1801 (?CO).

Example 7 - Reuse of imidazole ionic liquids-ZnX ₂ /base catalytic system

The [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system was repeatedly used to catalyze the cycloaddition reaction of CO ₂ and phenyloxirane to prepare the corresponding ethylene carbonate derivative. The chemical reaction formula is:

experiment procedure:

0.0139 g (0.10 mmol) of potassium carbonate, 0.0225 g (0.10 mmol) of zinc bromide, 0.8765 g (4 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. was added stirring, anti-gag stuffed sealed tube was then placed in a vacuum evacuation line, after the branch pipe is charged with a balloon of CO ₂ of high purity CO ₂ on the tube connected to the charge. A syringe was used to inject 0.2403 g (2 mmol) of phenyloxirane into a test tube, which was reacted at 25 ° C for 2 h.

After the reaction was stopped, 0.3407 g (2 mmol) of n-dodecane was added as an internal standard, and 15 mL of deionized water was further added. The reaction solution was extracted with ethyl acetate (3×10 mL). The upper layer is the ethyl acetate solution of the product and the lower layer is the solution of the ionic liquid, potassium carbonate and zinc bromide. The supernatant was removed with a dropper each time, and the upper ethyl acetate solution obtained three times was combined to measure GC-MS.

The above operation was repeated by further adding 0.2403 g (2 mmol) of phenyloxirane to the lower layer.

The above experiment was repeated three more times.

Experimental results:

Cycles	1	2	3	4	5
						GC Yield (%)	97	97	96	96	95

It can be seen that the [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system showed no signs of attenuating its catalytic activity after 5 repeated experiments. A slight change in yield may be caused by a certain loss of the total amount of [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ when the reaction solution is extracted with ethyl acetate after the end of each experiment.

Example 8 - Cycloaddition reaction of CO ₂ and phenyl oxirane with different partial pressures

The [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system is used to catalyze the cycloaddition reaction of different partial pressures of CO ₂ and phenyloxirane to prepare the corresponding ethylene carbonate derivatives. The chemical reaction formula is:

experiment procedure:

0.0139 g (0.10 mmol) of potassium carbonate, 0.0225 g (0.10 mmol) of zinc bromide, 0.8765 g (4 mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were placed in a 25 mL Schlenk test tube. In the middle, a stir bar was added, a back plug seal was placed, and then the test tube was placed on a vacuum line to evacuate, and then a balloon filled with a mixed gas of CO ₂ and N ₂ gas was attached to the branch pipe and inflated into the test tube. A syringe was used to inject 0.2403 g (2 mmol) of phenyloxirane into a test tube, which was reacted at 25 ° C for 2 h. After the reaction was stopped, 0.2403 g (2 mmol) of n-dodecane was added as an internal standard, and 15 mL of deionized water was added thereto, and extracted with ethyl acetate (1 × 10 mL) to measure GC-MS.

Three experiments were performed on three different partial pressures of CO ₂ .

Experimental results:

V CO2 /V N2	1:0	1:1	1:2
				PCO2(atm)	1	0.5	0.33
GC Yield (%)	99	89	31

It can be seen that when the partial pressure of CO ₂ is 0.5 atm, the [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ catalytic system still has a high catalytic conversion efficiency.

Example 9 - Imidazole type ionic liquid selected from 1-ethyl-3-methylimidazolium bromide ([Emim]Br) and 1-hexyl-3-methylimidazolium bromide ([Hmim]Br)

Imidazole ionic liquids-ZnX ₂ /base catalytic system from 1-ethyl-3-methylimidazolium bromide ([Emim]Br) or 1-hexyl-3-methylimidazolium bromide ([Hmim]Br) The composition of the imidazole-type ionic liquid), zinc bromide and potassium carbonate is referred to as [Emim]Br-ZnBr ₂ /K ₂ CO ₃ or [Hmim]Br-ZnBr ₂ /K ₂ CO ₃ system.

[Emim]Br-ZnBr ₂ /K ₂ CO ₃ or [Hmim]Br-ZnBr ₂ /K ₂ CO ₃ system catalyzes the cycloaddition reaction of CO ₂ and phenyl oxirane to prepare the corresponding ethylene carbonate derivative The method of chemical reaction is:

experiment procedure:

Weigh out 0.01139 g (0.10 mmol) of potassium carbonate, 0.0225 g (0.10 mmol) of zinc bromide, 1-ethyl-3-methylimidazolium bromide ([Emim]Br) or 1-hexyl-3-methyl bromide Imidazole ([Hmim]Br) (4 mmol) was placed in a 25 mL Schlenk tube, a stir bar was added, a plug was placed on the reverse plug, and then the tube was placed on a vacuum line to evacuate, and then the tube was connected with high purity. CO balloon tube ₂ and CO ₂ charged. A syringe was used to inject 0.2403 g (2 mmol) of phenyloxirane into a test tube, which was reacted at 25 ° C for 2 h. After the reaction was stopped, 0.2403 g (2 mmol) of n-dodecane was added as an internal standard, and 15 mL of deionized water was added thereto, and extracted with ethyl acetate (1 × 10 mL) to measure GC-MS.

Experimental results:

It can be seen that when the imidazole-type ionic liquid is replaced with 1-ethyl-3-methylimidazolium bromide or 1-hexyl-3-methylimidazolium bromide, the yield of the reaction is still good.

Example 10 - Zinc halide is selected from zinc chloride (ZnCl ₂ ) or zinc iodide (ZnI ₂ )

Imidazole ionic liquids-ZnX ₂ /base catalytic system, from 1-butyl-3-methylimidazolium bromide ([Bmim]Br) (imidazole type ionic liquid), zinc chloride or zinc iodide and potassium carbonate The composition of the compound is referred to as [Bmim]Br-ZnCl ₂ /K ₂ CO ₃ or [Bmim]Br-ZnI ₂ /K ₂ CO ₃ system.

[Bmim]Br-ZnCl ₂ /K ₂ CO ₃ or [Bmim]Br-ZnI ₂ /K ₂ CO ₃ system catalyzes the cycloaddition reaction of CO ₂ and phenyl oxirane to prepare the corresponding ethylene carbonate derivative The method of chemical reaction is:

experiment procedure:

Weigh out 0.01139 g (0.10 mmol) of potassium carbonate, zinc chloride (ZnCl ₂ ) or zinc iodide (ZnI ₂ ) (0.10 mmol), 1-butyl-3-methylimidazolium bromide ([Bmim]Br) 0.8765 g (4 mmol) was placed in a 25 mL Schlenk tube, a stir bar was added, a back plug was sealed, and the tube was placed on a vacuum line to evacuate, then a balloon filled with high purity CO ₂ was attached to the branch tube and The test tube is filled with CO ₂ . A syringe was used to inject 0.2403 g (2 mmol) of phenyloxirane into a test tube, which was reacted at 25 ° C for 2 h. After the reaction was stopped, 0.2403 g (2 mmol) of n-dodecane was added as an internal standard, and 15 mL of deionized water was added thereto, and extracted with ethyl acetate (1 × 10 mL) to measure GC-MS.

Experimental results:

Zinc halide (ZnX 2 )	Zinc chloride (ZnCl 2 )	Zinc iodide (ZnI 2 )
			GC Yield (%)	92	99

It can be seen that when the zinc halide is replaced by zinc chloride or zinc iodide, the yield of the reaction is still very satisfactory.

Example 11 - Base selection of sodium carbonate (Na ₂ CO ₃ ), sodium acetate (NaOAc), triethylamine (Et ₃ N)

Imidazole ionic liquids-ZnX ₂ /base catalytic system consisting of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) (imidazole-type ionic liquid), zinc bromide and sodium carbonate or sodium acetate or triethyl A composition of three amine compounds, designated as [Bmim]Br-ZnBr ₂ /Na ₂ CO ₃ or [Bmim]Br-ZnBr ₂ /NaOAc or [Bmim]Br-ZnBr ₂ /Et ₃ N system;

The [Bmim]Br-ZnBr ₂ /base system catalyzes the cycloaddition reaction of CO ₂ and phenyl oxirane to prepare the corresponding ethylene carbonate derivative. The chemical reaction formula is:

experiment procedure:

Weigh sodium carbonate or sodium acetate or triethylamine (0.10mmol), 0.0225g (0.10mmol) of zinc bromide, and 0.8765g (4mmol) of 1-butyl-3-methylimidazolium bromide ([Bmim]Br) In a 25 mL Schlenk tube, add a stir bar, plug the back plug seal, then place the tube on a vacuum line, then attach a balloon filled with high purity CO ₂ to the tube and fill the tube with CO ₂ . A syringe was used to inject 0.2403 g (2 mmol) of phenyloxirane into a test tube, which was reacted at 25 ° C for 2 h. After the reaction was stopped, 0.2403 g (2 mmol) of n-dodecane was added as an internal standard, and 15 mL of deionized water was added thereto, and extracted with ethyl acetate (1 × 10 mL) to measure GC-MS.

Experimental results:

Base	Sodium carbonate (Na 2 CO 3 )	Sodium acetate (NaOAc)	Triethylamine (Et 3 N)
				GC Yield (%)	82	80	95

It can be seen that when the base is changed to sodium carbonate, sodium acetate or triethylamine, the yield of the reaction is still high.

Example 12 - Catalytic ability of [Bmim]Br-ZnBr ₂ /K ₂ CO ₃ system using different amounts of cocatalyst (ZnBr ₂ and K ₂ CO ₃ ), different reaction temperatures and time conditions

[Bmim]Br-ZnBr ₂ /K ₂ CO ₃ system, a method for preparing a corresponding ethylene carbonate derivative by catalytic cycloaddition reaction of CO ₂ and phenyl oxirane, the chemical reaction formula is:

According to the reaction conditions of the following table, 0.5-5 mol% potassium carbonate, zinc bromide, and 1-butyl-3-methylimidazolium bromide ([Bmim]Br) 0.8765 g (4 mmol) were weighed into a 25 mL Schlenk test tube. was added stirring, anti-gag stuffed sealed tube was then placed in a vacuum evacuation line, after the branch pipe is charged with a balloon of CO ₂ of high purity CO ₂ on the tube connected to the charge. A syringe was used to inject 0.2403 g (2 mmol) of phenyloxirane into a test tube, and the reaction was carried out at a temperature of 20-35 ° C for 1-2.5 h. After the reaction was stopped, 0.2403 g (2 mmol) of n-dodecane was added as an internal standard, and 15 mL of deionized water was added thereto, and extracted with ethyl acetate (1 × 10 mL) to measure GC-MS.

Experimental results:

It can be seen that when the amount of cocatalyst (ZnBr ₂ and K ₂ CO ₃ ) is 0.5-5 mol%, the temperature is between 20-35 ° C, and the reaction time is within 1-2.5 h, the catalytic system is also very high. Catalytic conversion efficiency.

Claims (9)

1. An imidazole-type ionic liquid-zinc halide/base catalyst system characterized in that the catalytic system consists of an imidazole-type ionic liquid, a zinc halide and a base, and can catalyze carbon dioxide and a ring at 0.5-1 atm and 15-35 ° C. A cycloaddition reaction of an oxyethane derivative.
2. The imidazole-type ionic liquid-zinc halide/base catalyst system according to claim 1, wherein the imidazole-type ionic liquid is 1,3-dialkyl-substituted imidazole or imidazoline chloride, bromine or iodine. The salt has the structural formula of the following formula (1) and formula (2):

   

   n, m = 1, 2, 3, ... a positive integer;

   Q = Cl, Br, I, OH, OAc, OTs, OTf, NO ₃ , BF ₄ , PF ₆ ;

   Y = H, F, Cl, Br, I, OH, NH ₂ , SH, CN.
3. The imidazole-type ionic liquid-zinc halide/base catalyst system according to claim 1, wherein the zinc halide is ZnCl ₂ , ZnBr ₂ or ZnI ₂ .
4. The imidazole-type ionic liquid-zinc halide/base catalyst system according to claim 1, wherein the base is an inorganic base or an organic base.
5. The imidazole-type ionic liquid-zinc halide/base catalyst system according to claim 4, wherein the inorganic base is NaCO ₃ , K ₂ CO ₃ , Ce ₂ CO ₃ , NaHCO ₃ , NaOAc; The base is H ₂ NEt, HNEt ₂ , NEt ₃ , HN(i-Pr) ₂ , H ₂ N(t-Bu), HNCy ₂ , NMeCy ₂ , H ₂ NCH ₂ CH ₂ NH ₂ , H ₂ N (CH _{2 6} NH ₂ , PhNH ₂ , (p-CH ₃ )C ₆ H ₄ NH ₂ , NMe ₂ Ph, pyridine, piperididine, 1-methylpiperidine, DBU, DBN.
6. A method for preparing a ethylene carbonate derivative by an imidazole-type ionic liquid-zinc halide/base system, characterized in that an imidazole-type ionic liquid, a zinc halide and a base are mixed in proportion in an imidazole-type ionic liquid-zinc halide/base catalyst system, Then, CO ₂ or a balloon filled with CO ₂ , an ethylene oxide or an ethylene oxide derivative are added, and the mixture is reacted at 15-35 ° C for 1-5 h to obtain a corresponding ethylene carbonate derivative.
7. The method for preparing a ethylene carbonate derivative by catalytic reaction of an imidazole type ionic liquid-zinc halide/base system according to claim 6, wherein the amount of the zinc halide and the base is 0.5- of the molar amount of the ethylene oxide derivative. 5%, the imidazole type ionic liquid is used in an amount of from 1 to 3 times the molar amount of the ethylene oxide derivative.
8. The method for preparing a ethylene carbonate derivative by the imidazole-type ionic liquid-zinc halide/alkali system according to claim 6, wherein the CO ₂ pressure is 0.05 to 0.1 MPa.
9. The method for preparing a ethylene carbonate derivative by the imidazole type ionic liquid-zinc halide/base system according to claim 6, wherein the ethylene oxide derivative is represented by the following formula (3), formula (4) Any one of the compounds represented by the formula (5);

   

   Wherein: R ¹ , R ² , R ³ , R ⁴ =H, a saturated and unsaturated hydrocarbon group, Ar, (CH ₂ ) _n Cl, (CH ₂ ) _n Br, (CH ₂ ) _n OH, (CH ₂ ) _n NH ₂ , (CH ₂ ) _n OR, (CH ₂ ) _n OAr, (CH ₂ ) _n OCOR, (CH ₂ ) _n NHR, (CH ₂ ) _n NR ₂ , (CH ₂ ) _n OCOAr, (CH _{2 n} O(CH ₂ ) _m R, (CH ₂ ) _n O(CH ₂ ) _m Ar, COOR, COOAr, NR ₂ , NHR, SR;

   n, m = 1, 2, 3, ... a positive integer;

   Z=CH ₂ , NH, O, S, S=O, SO ₂ ;

   R is a saturated, unsaturated hydrocarbon group, CN;

   Ar is a substituted or unsubstituted aromatic group;

   Substituents on the aromatic group include F, Cl, Br, 1, OH, OTs, cN, NO ₂ , CHO, COOH, OSO ₃ H, alkoxy, ester, saturated and unsaturated hydrocarbon groups.