A catalyst for synthesizing cyclic carbonate compounds by epoxide carbon sequestration and a preparation method thereof

Abstract

The application discloses a catalyst for synthesizing a cyclic carbonate compound by carbon fixation of an epoxide and a preparation method thereof, and belongs to the technical field of green catalytic synthesis.The catalyst has low preparation cost, and raw materials are easy to obtain; the catalyst has no corrosiveness to general aluminum product metal containers, and is beneficial to industrial production.Through the catalyst system, carbon dioxide and an epoxide can be synthesized into a cyclic carbonate compound under relatively mild conditions.Meanwhile, the catalyst does not contain metal and halogen, and has great commercial value in fields such as biological medicines which have strict metal toxin residue limitation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of green catalytic synthesis technology, and particularly relates to a catalyst for synthesizing cyclic carbonates from epoxide and fixed carbon dioxide and a preparation method thereof. BACKGROUND

[0002] At present, the global atmospheric carbon dioxide concentration has exceeded 400 ppm, and according to the prediction of the International Panel on Climate Change (IPCC), the content of carbon dioxide in the atmosphere will increase to 570 ppm by 2100, and the global temperature will rise by about 1.9℃, causing land desertification and intensifying species extinction. In view of climate change, it is necessary to vigorously reduce the accumulation of carbon dioxide in the atmosphere. Carbon dioxide, as a stable, easily available and green C1 source, can be used as a carbon source to synthesize valuable chemicals. Carbon in carbon dioxide is in its highest oxidation state, which is inherently inert, and its chemical conversion process requires a large amount of energy input. A feasible method to overcome the energy barrier of carbon dioxide conversion is to use highly active reactants to compensate for its chemical inertness and to reasonably design catalysts to reduce the activation energy. The cycloaddition reaction (CCE) of carbon dioxide and epoxide to provide five-membered cyclic carbonates is a commercially valuable synthesis route. The obtained product is a five-membered cyclic carbonate, which can be used as a lithium ion battery electrolyte, an aprotic polar solvent, and can also be polymerized to prepare polycarbonates or non-isocyanate polyurethanes, etc. A series of catalysts have been developed to promote the cycloaddition reaction of carbon dioxide and epoxide, and metal complex catalysts and organic catalysts have been explored and successfully applied to CCE reaction.

[0003] In traditional CCE reaction, binary hydrogen-bonded organic catalysts and single-component (containing halogen) hydrogen-bonded organic catalysts have good catalytic effect. Among them, the hydrogen bond donor activates the epoxide, and the halide anion attacks the methylene carbon to make the epoxide further ring-opening. In most cases, halide anions are recognized as essential cocatalysts. However, halide anions have negative effects on process equipment, pollute the environment, and interfere with the further application of cyclic carbonates; and organic metal catalysts have metal residues in the catalytic reaction, which are easy to remain in the product as toxins. There are few reports on catalysts without metal and halogen, and the present application aims to develop a cheap and easily available catalyst without metal and halogen to catalyze the reaction of carbon dioxide and epoxide. SUMMARY

[0004] In order to solve the above problems, the present application provides a method for synthesizing cyclic carbonates from carbon dioxide and epoxide under relatively mild conditions, which uses a catalyst containing no metal and no halogen, does not require a solvent, and the raw material choline for synthesizing the catalyst can be obtained from a biological organism.

[0005] The application provides a synthesis method of cyclic carbonates, which adopts a hydroxypyridine choline ion pair catalyst shown in formula I to catalyze the cycloaddition reaction of an epoxide shown in formula II and carbon dioxide, so as to obtain a cyclic carbonate compound,

[0006]

[0007] The hydroxypyridine choline ion pair catalyst shown in formula I is synthesized by the reaction of a hydroxypyridine and an organic base; R 1 , R 2 are independently selected from hydrogen, C1-C4 branched / linear alkyl, vinyl, alkenyl, phenyl, halogen-substituted phenyl, chloro / bromo-substituted alkyl or R 3 -O-CH2-, and R 3 is selected from phenyl, C1-C4 branched or linear alkyl, C1-C3 alkyl-substituted phenyl or allyl; or R 1 and R 2 are connected to form a carbon six-membered ring.

[0008] Preferably, R 1 is selected from hydrogen, R 2 is selected from C1-C4 branched / linear alkyl, vinyl, alkenyl, phenyl, halogen-substituted phenyl, chloro / bromo-substituted alkyl or R 3 -O-CH2-, and R 3 is selected from phenyl, C1-C4 branched or linear alkyl, C1-C3 alkyl-substituted phenyl or allyl; or R 2 is selected from hydrogen, R 1 is selected from C1-C4 branched / linear alkyl, vinyl, alkenyl, phenyl, halogen-substituted phenyl, chloro / bromo-substituted alkyl or R 3 -O-CH2-, and R 3 is selected from phenyl, C1-C4 branched or linear alkyl, C1-C3 alkyl-substituted phenyl or allyl; or R 1 is selected from phenyl, and R 2 is selected from phenyl.

[0009] Further preferably, the epoxide shown in formula II is selected from the compounds shown in formulae 1-15 as follows:

[0010]

[0011] The preparation method of the hydroxypyridine choline ion pair catalyst shown in formula I is as follows:

[0012] Step one, under anhydrous and anaerobic conditions, an organic base and a hydroxypyridine are added in an inert gas or nitrogen atmosphere, and then ethanol or ethyl acetate is added for reaction.

[0013] Step two, after the reaction is completed, the hydroxypyridine choline ionic liquid is separated, vacuum dried to obtain the catalyst;

[0014] The organic base is choline hydroxide; the hydroxypyridine is 2-hydroxypyridine, 3-hydroxypyridine or 4-hydroxypyridine; the reaction molar ratio of choline hydroxide to hydroxypyridine is 1:2-2:1; the reaction temperature is 70-80℃, and the reaction time is 24-48h; the separation operation is vacuum distillation at 70-80℃; and the vacuum drying operation is drying in vacuum at 70-80℃ for 24-36h.

[0015] The preparation method of the cyclic carbonate compound is as follows: under anhydrous and anaerobic conditions, a reaction container is added with a hydroxypyridine choline ion pair catalyst shown in formula I and an epoxide shown in formula II, carbon dioxide is introduced, the reaction container is heated, and the product is separated after the reaction is completed;

[0016] The reaction molar ratio of the hydroxypyridine choline ion pair catalyst shown in formula I to the epoxide shown in formula II is 1:10-1:100; the reaction temperature is 25-120℃, the reaction time is 1-24h, and the initial reaction pressure is 0.1-2.0MPa; and the separation operation is column separation;

[0017] Preferably, the hydroxypyridine choline ion pair catalyst of formula I is used to catalyze the cycloaddition reaction of the epoxide monomers shown in formula 1-15 and carbon dioxide to obtain the cyclic carbonate compounds of formula 16-30:

[0018]

[0019]

[0020] The present application has the following advantages:

[0021] (1) The present application provides a method for synthesizing cyclic carbonates from carbon dioxide and epoxides under relatively mild conditions through the above-mentioned catalytic system. The catalyst used in the method does not contain metal, and has great commercial value in the fields of biological medicine and the like which have strict metal toxin residue restrictions.

[0022] (2) The catalytic system used in the present application does not contain halogen and does not need solvent, and has no corrosiveness to general aluminum metal containers, thus having great value in the production process.

[0023] (3) The raw materials of the synthesized catalyst, i.e. hydroxypyridine and choline, are simple and easy to obtain, the catalyst is easy to prepare, and the catalyst is low in price and natural green.

[0024] (4) The catalytic system used in the present application, the reaction condition is mild, and a higher yield (>90%) can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Hydro spectrum of catalyst 1 obtained in Example 1

[0026] Figure 2 Carbon spectrum of catalyst 1 obtained in Example 1

[0027] Figure 3 Hydro spectrum of catalyst 2 obtained in Example 2

[0028] Figure 4 Carbon spectrum of catalyst 2 obtained in Example 2

[0029] Figure 5 Hydro spectrum of catalyst 3 obtained in Example 3

[0030] Figure 6 Carbon spectrum of catalyst 3 obtained in Example 3

[0031] Figure 7 Hydro spectrum of cyclic carbonate product obtained in Example 4

[0032] Figure 8 Hydro spectrum of cyclic carbonate product obtained in Example 16

[0033] Figure 9 Hydro spectrum of cyclic carbonate product obtained in Example 17

[0034] Figure 10 Hydro spectrum of cyclic carbonate product obtained in Example 18

[0035] Figure 11 Hydro spectrum of cyclic carbonate product obtained in Example 19

[0036] Figure 12 Hydro spectrum of cyclic carbonate product obtained in Example 20

[0037] Figure 13 Hydro spectrum of cyclic carbonate product obtained in Example 21

[0038] Figure 14 Hydro spectrum of cyclic carbonate product obtained in Example 23 DETAILED DESCRIPTION

[0039] The present application can be further illustrated by the following examples which are intended to be purely exemplary of the present application and are not intended to be limiting thereof. Any person skilled in the art can understand that the examples do not limit the present application in any way and that appropriate modifications and data transformation can be made thereto without departing from the spirit and scope of the present application.

[0040] The nuclear magnetic resonance hydrogen spectrum involved in the examples was determined by using a Bruker Ascend™-400 type nuclear magnetic resonance hydrogen spectrometer of Bruker Company. Deuterated reagent used was deuterated chloroform (CDCI3).

[0041] I. Preparation of catalyst

[0042] Example 1:

[0043] Preparation of catalyst 1, the reaction bottle was dehydrated and deoxygenated, 10 mmol of choline hydroxide and 10 mmol of 2-hydroxypyridine were added under inert gas protection, 20 mL of ethanol was added as solvent, and stirred at 70°C for 24 hours. The ethanol and water were distilled off under reduced pressure at 70°C. The obtained 2-hydroxypyridine choline ionic liquid was dried in vacuum at 70°C for 24 hours to remove trace amount of water. The yield (purification) was 98.5%. 1 H NMR (400 MHz, DMSO-d6) δ 7.64 - 7.57 (m, 1H), 7.04 (ddd, J = 7.6, 6.3, 2.4 Hz, 1H), 5.97 - 5.89 (m, 2H), 3.91 (dq, J = 7.8, 2.8 Hz, 2H), 3.52 - 3.43 (m, 2H), 3.15 (s, 9H). 13 C NMR (101 MHz, DMSO-d6) δ 171.18, 146.25, 136.76, 114.31, 105.03 (d, J = 3.2 Hz), 68.70 - 65.08 (m), 54.97, 54.02 - 52.42 (m).

[0044] Example 2:

[0045] Preparation of catalyst 2, the reaction bottle was dehydrated and deoxygenated, 10 mmol of choline hydroxide and 10 mmol of 3-hydroxypyridine were added under inert gas protection, 20 mL of ethanol was added as solvent, and stirred at 70°C for 24 hours. The ethanol and water were distilled off under reduced pressure at 70°C. The obtained 3-hydroxypyridine choline ionic liquid was dried in vacuum at 70°C for 24 hours to remove trace amount of water. The yield (purification) was 97.8%. 1H NMR (400MHz, DMSO-d6) δ7.61(d,J=2.9Hz,1H),7.29(dd,J=4.4,1.5Hz,1H),6.77(dd,J=8.3,4. 4Hz, 1H), 6.47 (ddd, J=8.3, 3.0, 1.5Hz, 1H), 3.86–3.78 (m, 2H), 3.40–3.33 (m, 2H), 3.12 (s, 9H). 13 C NMR (101MHz, DMSO-d6) δ165.18,142.03,130.52,123.62,122.69,68.16–66.60(m),55.13,53.86–52.41(m).

[0046] Example 3:

[0047] For the preparation of catalyst 3, the reaction flask was dehydrated and deoxygenated. Under inert gas protection, 10 mmol of choline hydroxide and 10 mmol of 4-hydroxypyridine were added, along with 20 mL of ethanol as a solvent. The mixture was stirred at 70 °C for 24 hours. Ethanol and water were then distilled off under reduced pressure at 70 °C. The resulting 4-hydroxypyridinecholine ionic liquid was dried under vacuum at 70 °C for 24 hours to remove trace amounts of water. The yield (purified) was 99.1%. 1 H NMR (400MHz, DMSO-d6) δ7.70–7.64(m,2H),6.07–6.01(m,2H),3.86–3.78(m,2H),3.41–3.34(m,2H),3.11(s,9H). 13 C NMR(101MHz,DMSO-d6)δ174.74,148.81,115.91,70.86–66.00(m),55.08,54.12–52.59(m).

[0048] II. Synthesis of Cyclic Carbonates

[0049] Example 4:

[0050] The reaction flask was dehydrated and deoxygenated. Under inert gas protection, 0.5 mmol of catalyst 1 and 10 mmol of styrene oxide (compound 6) were added. The inert gas in the reaction flask was replaced three times with carbon dioxide. Then, a balloon filled with carbon dioxide was attached to the reaction flask, and the flask was placed in an oil bath at 120°C for 12 hours. After the reaction was completed, the mixture was cooled, separated by chromatographic column chromatography (petroleum ether:ethyl acetate = 2:1), and the product was dried to give a pale yellow liquid. The conversion rate was 91.7%. 1H NMR (400 MHz, Chloroform-d) δ 7.45 - 7.31 (m, 5H), 5.65 (t, J = 8.0 Hz, 1H), 4.77 (t, J = 8.4 Hz, 1H), 4.29 (dd, J = 8.7, 7.8 Hz, 1H).

[0051] Example 5:

[0052] The reaction flask was dehydrated and deoxygenated, and 0.5 mmol of catalyst 2 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas in the reaction flask was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied to the reaction flask, which was placed in an oil bath at 120°C for 12 hours. After the reaction was completed, it was cooled, separated by column chromatography (petroleum ether: ethyl acetate = 2:1), and then the product was dried to obtain a light yellow liquid with a conversion rate of 97.1%. 1 H NMR (400 MHz, CDCl3).

[0053] Example 6:

[0054] The reaction flask was dehydrated and deoxygenated, and 0.5 mmol of catalyst 3 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas in the reaction flask was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied to the reaction flask, which was placed in an oil bath at 120°C for 12 hours. After the reaction was completed, it was cooled, separated by column chromatography (petroleum ether: ethyl acetate = 2:1), and then the product was dried to obtain a light yellow liquid with a conversion rate of 97.4%. 1 H NMR (400 MHz, CDCl3).

[0055] Example 7:

[0056] The reaction flask was dehydrated and deoxygenated, and 0.5 mmol of catalyst 3 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas in the reaction flask was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied to the reaction flask, which was placed in an oil bath at 120°C for 12 hours. After the reaction was completed, it was cooled, separated by column chromatography (petroleum ether: ethyl acetate = 2:1), and then the product was dried to obtain a light yellow liquid with a conversion rate of 97.4%. 1 H NMR (400 MHz, CDCl3).

[0057] Example 8:

[0058] The reaction vessel was subjected to water and oxygen removal operation, and 0.5 mmol of catalyst 3 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas of the reaction vessel was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied on the reaction vessel, and it was put into an oil bath at 120°C for 18 hours. After the reaction was completed, it was cooled, separated by chromatographic column (petroleum ether: ethyl acetate = 2: 1), and then the product was dried to obtain a light yellow liquid, and the conversion rate was 95.4%. 1 H NMR (400MHz, CDCI3).

[0059] Example 9:

[0060] The reaction vessel was subjected to water and oxygen removal operation, and 0.5 mmol of catalyst 3 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas of the reaction vessel was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied on the reaction vessel, and it was put into an oil bath at 120°C for 18 hours. After the reaction was completed, it was cooled, separated by chromatographic column (petroleum ether: ethyl acetate = 2: 1), and then the product was dried to obtain a light yellow liquid, and the conversion rate was 95.4%. 1 H NMR (400MHz, CDCI3).

[0061] Example 10:

[0062] The reaction vessel was subjected to water and oxygen removal operation, and 0.5 mmol of catalyst 3 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas of the reaction vessel was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied on the reaction vessel, and it was put into an oil bath at 120°C for 18 hours. After the reaction was completed, it was cooled, separated by chromatographic column (petroleum ether: ethyl acetate = 2: 1), and then the product was dried to obtain a light yellow liquid, and the conversion rate was 95.4%. 1 H NMR (400MHz, CDCI3).

[0063] Example 11:

[0064] The reaction vessel was subjected to water and oxygen removal operation, and 0.5 mmol of catalyst 3 and 10 mmol of phenylacetylene were added under inert gas protection. The inert gas of the reaction vessel was replaced with carbon dioxide three times, and then a balloon filled with carbon dioxide was tied on the reaction vessel, and it was put into an oil bath at 120°C for 18 hours. After the reaction was completed, it was cooled, separated by chromatographic column (petroleum ether: ethyl acetate = 2: 1), and then the product was dried to obtain a light yellow liquid, and the conversion rate was 95.4%. 1 H NMR (400MHz, CDCI3).

[0065] Example 12:

[0066] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.1 mmol of catalyst 3 and 10 mmol of styrene oxide (compound 6) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, and then 1 MPa of carbon dioxide gas was injected. The reaction was carried out in an oil bath at 120°C for 12 hours. After the reaction was completed, the product was separated by column chromatography (petroleum ether: ethyl acetate = 2: 1) after cooling, and then dried to obtain a light yellow liquid. The conversion rate was 35.5%. 1 H NMR (400MHz, CDCI3).

[0067] Example 13:

[0068] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.1 mmol of catalyst 3 and 10 mmol of styrene oxide (compound 6) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, and then 1 MPa of carbon dioxide gas was injected. The reaction was carried out in an oil bath at 120°C for 12 hours. After the reaction was completed, the product was separated by column chromatography (petroleum ether: ethyl acetate = 2: 1) after cooling, and then dried to obtain a light yellow liquid. The conversion rate was 35.5%. 1 H NMR (400MHz, CDCI3).

[0069] Example 14:

[0070] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.1 mmol of catalyst 3 and 10 mmol of styrene oxide (compound 6) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, and then 1 MPa of carbon dioxide gas was injected. The reaction was carried out in an oil bath at 120°C for 12 hours. After the reaction was completed, the product was separated by column chromatography (petroleum ether: ethyl acetate = 2: 1) after cooling, and then dried to obtain a light yellow liquid. The conversion rate was 35.5%. 1 H NMR (400MHz, CDCI3).

[0071] Example 15:

[0072] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.1 mmol of catalyst 3 and 10 mmol of styrene oxide (compound 6) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, and then 1 MPa of carbon dioxide gas was injected. The reaction was carried out in an oil bath at 120°C for 12 hours. After the reaction was completed, the product was separated by column chromatography (petroleum ether: ethyl acetate = 2: 1) after cooling, and then dried to obtain a light yellow liquid. The conversion rate was 35.5%. 1 H NMR (400MHz, CDCI3).

[0073] Example 16:

[0074] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.5 mmol of catalyst 3 and 10 mmol of 2-(tert-butoxymethyl)oxirane (compound 10) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, then 1.0 MPa of carbon dioxide gas was injected, and it was placed in an oil bath at 120°C for 12 hours. After the reaction was completed, it was cooled, separated by column chromatography (petroleum ether: ethyl acetate = 2: 1), and the product was dried to obtain a light yellow liquid with a conversion rate of 93.1%. 1 HNMR (400 MHz, Chloroform-d) δ 4.76 (dddd, J = 8.2, 5.8, 4.6, 3.6 Hz, 1H), 4.47 (t, J = 8.3 Hz, 1H), 4.38 (dd, J = 8.3, 5.8 Hz, 1H), 3.61 (dd, J = 10.3, 4.6 Hz, 1H), 3.52 (dd, J = 10.3, 3.6 Hz, 1H), 1.19 (s, 9H).

[0075] Example 17:

[0076] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.5 mmol of catalyst 3 and 10 mmol of 2-(tert-butoxymethyl)oxirane (compound 10) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, then 1.0 MPa of carbon dioxide gas was injected, and it was placed in an oil bath at 120°C for 12 hours. After the reaction was completed, it was cooled, separated by column chromatography (petroleum ether: ethyl acetate = 2: 1), and the product was dried to obtain a light yellow liquid with a conversion rate of 93.1%. 1 H NMR (400 MHz, Chloroform-d) δ 7.34 - 7.27 (m, 2H), 7.10 - 6.97 (m, 1H), 6.92 (ddd, J = 8.8, 2.3, 1.0 Hz, 2H), 5.03 (dddd, J = 8.1, 5.9, 4.3, 3.6 Hz, 1H), 4.76 - 4.43 (m, 2H), 4.36 - 4.06 (m, 2H).

[0077] Example 18:

[0078] The stainless steel pressure-resistant tube was dehydrated and deoxygenated. Under inert gas protection, 0.5 mmol of catalyst 3 and 10 mmol of 2-((o-tolyloxy)methyl)ethylene oxide (compound 13) were added. The inert gas in the reaction flask was replaced with carbon dioxide three times, and then 1.0 MPa of carbon dioxide gas was introduced. The flask was placed in an oil bath at 120 °C and reacted for 12 hours. After the reaction was completed, the mixture was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic resonance quantification using mesitylene as an internal standard. The conversion rate was found to be 95.2%. 1 H NMR(400MHz,Chloroform-d)δ7.21–7.12(m,2H),6.93(td,J=7.4,1.1Hz,1H),6.78(dd,J=8.6,1.1Hz,1H),5.05(ddt ,J=8.6,5.5,3.3Hz,1H),4.68–4.54(m,2H),4.27(dd,J=10.6,3.6Hz,1H),4.14(dd,J=10.6,3.1Hz,1H),2.22(s,3H).

[0079] Example 19:

[0080] The stainless steel pressure tube was dehydrated and deoxygenated. Under inert gas protection, 0.1 mmol of catalyst 2 and 10 mmol of epichlorohydrin (compound 1) were added. The inert gas in the reaction flask was replaced three times with carbon dioxide, and then 1.0 MPa of carbon dioxide gas was introduced. The flask was placed in an oil bath at 120°C and reacted for 12 hours. After the reaction was completed, the mixture was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic resonance quantification using mesitylene as an internal standard. The conversion rate was found to be 98.2%. 1 H NMR (400MHz, Chloroform-d) δ4.95 (dtd, J=8.2, 5.7, 4.1Hz, 1H), 4.59 (dd, J=8.9, 8.2Hz, 1H), 4.42 (dd, J=8.9, 5.7Hz, 1H), 3.82–3.69 (m, 2H).

[0081] Example 20:

[0082] The stainless steel pressure-resistant tube was dehydrated and deoxygenated. Under inert gas protection, 0.25 mmol of catalyst 3 and 10 mmol of 3,4-epoxy-1-butene (compound 3) were added. The inert gas in the reaction flask was replaced with carbon dioxide three times, and then 1.0 MPa of carbon dioxide gas was introduced. The flask was placed in an oil bath at 100 °C and reacted for 12 hours. After the reaction was completed, the mixture was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic resonance quantification using mesitylene as an internal standard. The conversion rate was found to be 88.7%. 1H NMR(400MHz,Chloroform-d)δ5.89(ddd,J=17.2,10.4,7.0Hz,1H),5.50(dt,J=17.1,0.9Hz,1H),5 .43(dt,J=10.4,0.9Hz,1H),5.17–5.07(m,1H),4.59(t,J=8.3Hz,1H),4.15(dd,J=8.6,7.5Hz,1H).

[0083] Example 21:

[0084] The stainless steel pressure-resistant tube was dehydrated and deoxygenated. Under inert gas protection, 0.5 mmol of catalyst 1 and 10 mmol of 2-butyl ethylene oxide (compound 4) were added. The inert gas in the reaction flask was replaced with carbon dioxide three times, and then 1.0 MPa of carbon dioxide gas was introduced. The flask was placed in an oil bath at 120°C and reacted for 12 hours. After the reaction was completed, the mixture was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic resonance quantification using mesitylene as an internal standard. The conversion rate was found to be 95.2%. 1 H NMR(400MHz,Chloroform-d)δ4.69(qd,J=7.5,5.4Hz,1H),4.55–4.47(m,1H),4.05(dd,J=8.4,7.2Hz,1 H),1.78(dddd,J=14.0,10.2,7.5,4.8Hz,1H),1.74–1.60(m,1H),1.52–1.20(m,4H),0.99–0.83(m,3H).

[0085] Example 22:

[0086] The stainless steel pressure tube was dehydrated and deoxygenated. Under inert gas protection, 0.1 mmol of catalyst 2 and 10 mmol of 2-(p-chlorophenyl)ethylene oxide (compound 7) were added. The inert gas in the reaction flask was replaced three times with carbon dioxide, and then 1.0 MPa of carbon dioxide gas was introduced. The flask was placed in an oil bath at 120 °C and reacted for 10 hours. After the reaction was completed, the mixture was cooled, and the conversion rate of the epoxide in the reaction solution was determined by quantitative NMR using trimethylbenzene as an internal standard. The conversion rate was 89.3%. ¹H NMR (400 MHz, CDCl₃) was used.

[0087] Example 23:

[0088] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.5 mmol of catalyst 3 and 10 mmol of allyl glycidyl ether (compound 11) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, then 1.0 MPa of carbon dioxide gas was injected, and it was placed in a 100°C oil bath for 8 hours. After the reaction was completed, it was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic quantification with mesitylene as an internal standard to obtain a conversion rate of 75.6%.1H NMR (400 MHz, Chloroform-d) δ 5.86 (ddt, J = 17.3, 10.3, 5.6 Hz, 1H), 5.28 (dq, J = 17.2, 1.6 Hz, 1H), 5.22 (dq, J = 10.4, 1.3 Hz, 1H), 5.05 (q, J = 6.6 Hz, 1H), 4.82 (ddt, J = 8.1, 6.1, 3.9 Hz, 1H), 4.50 (t, J = 8.4 Hz, 1H), 4.40 (dd, J = 8.4, 6.1 Hz, 1H), 4.08 - 3.98 (m, 1H), 3.80 - 3.56 (m, 2H).

[0089] Example 24:

[0090] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.5 mmol of catalyst 1 and 10 mmol of cyclohexene oxide (compound 14) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, then 2.0 MPa of carbon dioxide gas was injected, and it was placed in a 120°C oil bath for 18 hours. After the reaction was completed, it was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic quantification with mesitylene as an internal standard to obtain a conversion rate of 15.6%.1H NMR (400 MHz, CDCl3).

[0091] Example 25:

[0092] A stainless steel pressure tube was dehydrated and deoxygenated, and 0.5 mmol of catalyst 1 and 10 mmol of trans-1,2-diphenyl oxirane (compound 15) were added under inert gas protection. The inert gas in the reaction bottle was replaced with carbon dioxide three times, then 2.0 MPa of carbon dioxide gas was injected, and it was placed in a 120°C oil bath for 24 hours. After the reaction was completed, it was cooled, and the conversion rate of the epoxide in the reaction solution was determined by nuclear magnetic quantification with mesitylene as an internal standard to obtain a conversion rate of 18.2%.1H NMR (400 MHz, CDCl3).

Claims

1. A method for preparing a catalyst for carbonation of an epoxide to synthesize a cyclic carbonate compound, characterized by: The hydroxypyridine choline ionic pair catalyst shown in formula I is used to catalyze the cycloaddition reaction of the epoxide shown in formula II with carbon dioxide to obtain a cyclic carbonate compound, The hydroxypyridine choline ion pair catalyst of formula I is synthesized from a hydroxypyridine and an organic base; the epoxide of formula II 1 , R 2 is independently selected from hydrogen, C1-C4 branched / linear alkyl, vinyl, allyl, phenyl, halogen substituted phenyl, chloro / bromo substituted alkyl, or R 3 -O-CH2-, said R 3 is selected from phenyl, C1-C4 branched / linear alkyl, phenyl substituted with C1-C3 alkyl, or allyl; or R 1 and R 2 are joined to form a carbon six membered ring.

2. The production method according to claim 1, wherein The preparation method of the hydroxypyridine choline ionic pair catalyst shown in formula I is as follows: Step one, under anhydrous and anaerobic conditions, an organic base and a hydroxypyridine are added in an inert gas or nitrogen atmosphere, and then ethanol or ethyl acetate is added for reaction; Step two, after the reaction is completed, the hydroxypyridine choline ionic liquid is separated out, and then vacuum drying treatment is performed to obtain the catalyst.

3. The production method according to claim 2, wherein The organic base is choline hydroxide; the hydroxypyridine is 2-hydroxypyridine, 3-hydroxypyridine or 4-hydroxypyridine.

4. The production method according to claim 2, wherein The reaction feeding molar ratio of the organic base to the hydroxypyridine is 1:2-2:1; the reaction temperature is 70-80℃, and the reaction time is 24-48h; the separation operation is vacuum distillation at 70-80℃; and the vacuum drying operation is drying in vacuum at 70-80℃ for 24-36h.

5. The production method according to claim 1, wherein The preparation method of the cyclic carbonate compound is as follows: under anhydrous and anaerobic conditions, the hydroxypyridine choline ionic pair catalyst shown in formula I and the epoxide shown in formula II are added into a reaction container in an inert gas or nitrogen atmosphere, carbon dioxide is introduced, the reaction container is heated, and then the product is separated out after the reaction is completed.

6. The production method according to claim 5, wherein The reaction feeding molar ratio of the hydroxypyridine choline ionic pair catalyst shown in formula I to the epoxide shown in formula II is 1:10-1:100; the reaction temperature is 25-120℃, the reaction time is 1-24h, and the initial reaction pressure is 0.1-2.0MPa.

7. The production method according to claim 1, wherein R of the epoxide of formula II 1 selected from hydrogen, R 2 selected from C1-C4 branched / linear alkyl, vinyl, alkenyl, phenyl, halogen substituted phenyl, chloro / bromo substituted alkyl or R 3 -O-CH2-, said R 3 selected from phenyl, C1-C4 branched / linear alkyl, phenyl substituted with C1-C3 alkyl or allyl; or R 2 selected from hydrogen, R 1 selected from C1-C4 branched / linear alkyl, vinyl, alkenyl, phenyl, halogen substituted phenyl, chloro / bromo substituted alkyl or R 3 -O-CH2-, said R 3 selected from phenyl, C1-C4 branched / linear alkyl, phenyl substituted with C1-C3 alkyl or allyl; or R 1 selected from phenyl, R 2 selected from phenyl.

8. The production method according to claim 1, wherein The epoxide shown in formula II is selected from the compounds of formulae 1-15:

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