An ionic compound and a method for catalytic synthesis of cyclic carbonates

Abstract

The application belongs to the field of catalytic synthesis of fine chemical products, and particularly relates to an ionic compound and a method for catalytically synthesizing cyclic carbonate. The application provides an ionic compound, which comprises an anion as shown in formula (I) or formula (II); wherein X is selected from O, S and Se, and the value of L is 0 or 1; the anion in the ionic compound has suitable nucleophilicity and leaving property, can be combined with other active positive ions or metal ions to form a catalytic system with good solubility, and is particularly suitable for being used in a cycloaddition reaction involving carbon dioxide. Meanwhile, the application further provides a catalytic method for synthesizing cyclic carbonate, which uses a catalytic system containing the ionic compound, so that cyclic carbonate can be synthesized in a solvent-free, low-halogen or halogen-free, low-catalyst-amount and mild reaction condition mode with high efficiency, high conversion rate and high chemical selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic synthesis of fine chemical products, in particular to an ionic compound and a method for catalytic synthesis of cyclic carbonate. BACKGROUND

[0002] With the development of industrialization, the CO2 content in the atmosphere has increased significantly, which has caused a series of environmental problems and has endangered the survival of some species. At present, in the technology of comprehensive utilization of carbon dioxide, the cycloaddition reaction of CO2 and epoxide not only can produce cyclic carbonate products with high value, but also can meet the principle of atom economy, and is considered as one of the important ways for efficient CO2 fixation. However, the cycloaddition reaction of CO2 and epoxide under natural conditions is insufficient to occur, and often needs suitable catalysts, high pressure and high temperature to promote the occurrence of the process.

[0003] At present, the strategy of combining "halogen-containing quaternary ammonium salt" with "metal-based compound or hydrogen bond donor compound" to form a catalytic system is widely studied, and such a catalytic system shows excellent catalytic activity and chemical selectivity. The design principle of this catalytic system is based on the theoretical assumption that "the ring opening of epoxide is the rate-determining step of cycloaddition reaction"; among them, the metal-based compound and the hydrogen bond donor are combined with the oxygen atom of the epoxide by Lewis acid-base interaction and hydrogen bond interaction, respectively, to activate the epoxide, and the nucleophilic halogen ion in the "halogen-containing quaternary ammonium salt" acts as a Lewis base, which is easy to make the activated epoxide undergo ring-opening reaction. However, most of the metal compounds need a complex synthesis process, which is high in cost and hinders the large-scale development; the catalytic system constructed with hydrogen bond donor compounds mostly shows catalytic effect at room temperature, while the hydrogen bond will be destroyed under heating conditions, resulting in a small temperature window and difficulty in meeting the actual industrial production requirements. In addition, the use of halogen-containing quaternary ammonium salt or poorly soluble metal halide in the catalytic system will cause problems such as high temperature and high pressure required for reaction, difficulty in solvent separation, easy corrosion of production equipment, and environmental pollution.

[0004] Therefore, it is urgent to develop a catalyst or catalytic system for the cycloaddition reaction of CO2 and epoxide, which has high catalytic activity and selectivity, is easy to prepare, has easily available raw materials, is green and environmentally friendly, has good solubility, and has suitable nucleophilicity and leaving group, and can be selectively used with Lewis acid. SUMMARY

[0005] In order to overcome the problems existing in the prior art, the purpose of the present application is to provide an ionic compound catalyst and a low-cost, efficient, green, safe and easy-to-separate and purify product catalytic method for synthesizing cyclic carbonate.

[0006] The present application is particularly aimed at: according to the production reaction condition requirements, environmental and economic requirements, the active characteristics of the epoxide compound, designing the ionic compound with suitable structure and charge to construct the catalytic system with suitable electrophilic and nucleophilic function, so as to realize the production of cyclic carbonate by the reaction of CO2 and epoxide compound under the conditions of reducing or removing the use of halogen-containing catalyst, solvent-free and relatively mild conditions.

[0007] The key of the present application is: through deprotonation reaction, various compounds containing N-H (i.e. active H) with rich structure, including urea, thiourea, selenourea, sulfonylurea, squaric amide, amide, thioamide, carbamate, thiocarbamate, etc., are converted into ionic compounds with suitable nucleophilicity and leaving property, and then applied to the reaction of CO2 and epoxide compound to generate cyclic carbonate. The ionic compound used in the method can catalyze the cycloaddition reaction of CO2 and epoxide compound to selectively generate cyclic carbonate.

[0008] It is particularly necessary to point out that the anion in the ionic compound with suitable nucleophilicity and leaving property is relatively key, and through the design of the anion part structure, the catalytic activity (i.e. nucleophilicity and leaving property) can be flexibly adjusted. In addition, the change of the cation structure has a great influence on the coulomb interaction between the anion and the cation, and also provides an adjustment window for the catalytic activity.

[0009] On this basis, the present application can play more excellent catalytic activity in the ring-opening reaction of epoxide compound by using the ionic compound and electrophilic Lewis acid in combination, or making the substituent group of the ionic compound contain an electrophilic group to form a single-molecule multifunctional catalyst. At the same time, the catalyst also has the advantages of simple preparation, low cost, rich structure, wide application range of epoxide compound, etc., and can efficiently and highly chemoselectively synthesize cyclic carbonate under solvent-free and relatively mild reaction conditions, and the product is easy to separate and purify.

[0010] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0011] In a first aspect, the present application provides an ionic compound, which comprises an anion as shown in formula (I) or formula (II);

[0012]

[0013] wherein X is selected from O, S, Se; Y is selected from C(R3)2, NR3, O, S; R1, R2, R3, R4 are independently selected from H, phenyl, trifluoromethyl-substituted phenyl, tolyl, benzyl, C3-C8 cycloalkyl, C1-C20 chain alkyl, heteroatom-substituted phenyl, heteroatom-substituted benzyl, heteroatom-substituted C3-C8 cycloalkyl, heteroatom-substituted C1-C20 chain alkyl, borane-substituted C1-C8 chain alkyl, C3-C20 heterocyclic group, C5-C20 heteroaryl group;

[0014] In formula (II), R4 is directly connected to any carbon atom of the ring, and L is 0 or 1.

[0015] Preferably, when X is selected from O, S, Y is not NR3.

[0016] Specifically, R4 is a substituent connected to any carbon atom of the ring; the structure of the tolyl group is the structure of the benzyl group is "*" represents a substitution position or a connection position.

[0017] Taking C3-C8 cycloalkyl and C1-C20 chain alkyl as examples, C3-C8 cycloalkyl represents a cycloalkyl group with a carbon atom number of 3-8, and the carbon atom number is the total of the carbon atoms inside and outside the cycloalkyl ring; C1-C20 chain alkyl represents a chain alkyl group with a carbon atom number of 1-20.

[0018] The "heteroatom" in the heteroatom-substituted phenyl group, the heteroatom-substituted benzyl group, the heteroatom-substituted C3-C8 cycloalkyl group, and the heteroatom-substituted C1-C20 chain alkyl group is selected from at least one of B, N, O, Si, P, and S.

[0019] The heteroatom in the heterocyclic group and the heteroaryl group is selected from at least one of B, N, O, Si, P, and S.

[0020] Preferably, the structure of the ionic compound is shown in formula (III) or formula (IV):

[0021]

[0022] wherein X is selected from O, S, Se; Y is selected from C(R3)2, NR3, O, S;

[0023] R1, R2, R3, R4 are independently selected from one of H, phenyl, tolyl, benzyl, C3-C8 cycloalkyl, C1-C20 chain alkyl, C1-C8 chain alkyl substituted by borane substituent, C3-C20 heterocyclic group, C5-C20 heteroaryl; in formula (IV), R4 is directly connected to any carbon atom on the ring, and L is 0 or 1;

[0024] M is selected from Li, Na, K, Cs;

[0025] wherein, R5-R12 are independently selected from one of C1-C8 alkyl, benzyl; Z is selected from one of N, P.

[0026] Preferably, R5-R12 are independently selected from one of C1-C8 chain alkyl.

[0027] Preferably, the structure of C3 chain alkyl substituted by borane substituent is as follows:

[0028] wherein, "*" represents the substitution position or the connection position.

[0029] Preferably, the ionic compound is selected from any one of the following structural formulae:

[0030]

[0031] Further preferably, the ionic compound is selected from any one of the following structural formulae:

[0032]

[0033] In a second aspect, the present application provides a method for catalytic synthesis of cyclic carbonate, comprising the following steps:

[0034] mixing an epoxide compound, carbon dioxide and a catalyst to perform catalytic cycloaddition reaction to obtain a cyclic carbonate;

[0035] wherein, the catalyst comprises the ionic compound of the first aspect. Specifically, the ionic compound comprises an anion as shown in formula (I) or formula (II).

[0036]

[0037] wherein X is selected from O, S, Se; Y is selected from C(R3)2, NR3, O, S; R1, R2, R3, R4 are independently selected from H, phenyl, trifluoromethyl-substituted phenyl, tolyl, benzyl, C3-C8 cycloalkyl, C1-C20 chain alkyl, heteroatom-substituted phenyl, heteroatom-substituted benzyl, heteroatom-substituted C3-C8 cycloalkyl, heteroatom-substituted C1-C20 chain alkyl, borane-substituted C1-C8 chain alkyl, C3-C20 heterocyclic group, C5-C20 heteroaryl group;

[0038] In formula (II), R4 is directly connected to any carbon atom on the ring, and L has a value of 0 or 1.

[0039] Specifically, the “heteroatom” in the heteroatom-substituted phenyl, heteroatom-substituted benzyl, heteroatom-substituted C3-C8 cycloalkyl, and heteroatom-substituted C1-C20 chain alkyl is selected from at least one of B, N, O, Si, P, and S.

[0040] Preferably, the ionic compound has a structure as shown in formula (III) or formula (IV):

[0041]

[0042] wherein X is selected from O, S, Se; Y is selected from C(R3)2, NR3, O, S;

[0043] R1, R2, R3, R4 are independently selected from H, phenyl, tolyl, benzyl, C3-C8 cycloalkyl, C1-C20 chain alkyl, borane-substituted C1-C8 chain alkyl, C3-C20 heterocyclic group, C5-C20 heteroaryl group; in formula (IV), R4 is directly connected to any carbon atom on the ring, and L has a value of 0 or 1.

[0044] M is selected from Li, Na, K, Cs;

[0045] wherein R5-R12 are independently selected from C1-C8 alkyl, benzyl; Z is selected from N, P.

[0046] Preferably, the borane-substituted C3 chain alkyl has a structure as follows:

[0047] wherein “*” represents a substitution position or a connection position.

[0048] Preferably, the ionic compound is selected from any one of the following structural formulas:

[0049]

[0050] Further preferably, the ionic compound is selected from any one of the following structural formulae:

[0051]

[0052] Preferably, the catalyst comprises an ionic compound and a Lewis acid.

[0053] Further preferably, the catalyst consists of an ionic compound and a Lewis acid.

[0054] Specifically, the present application can propose two catalytic reaction systems, one is a catalytic reaction system with an ionic compound as a catalyst, and the other is a catalytic reaction system with an ionic compound and a Lewis acid as a catalyst.

[0055] Preferably, the Lewis acid is selected from at least one of trihydrocarbylborane, aryl-substituted borane, heteroaryl-substituted borane, organoborate ester, dihydrocarbylboron halide, boron halide, organoaluminum compound, metal halide, metal triflate, urea, thiourea, squaraine.

[0056] Specifically, the metal halide is a metal halide salt, and the metal in the metal halide is selected from at least one of Mg, Al, K, Ca, Ti, Fe, Co, Cu, Zn, rare earth metal.

[0057] Preferably, the trihydrocarbylborane is selected from at least one of trimethylboron, triethylboron, triisopropylboron, tri-n-butylboron, tri-sec-butylboron, B-isopinocampyl-9-borabicyclo[3.3.1]nonane. The specific structure is as follows:

[0058]

[0059] Preferably, the aryl-substituted borane is selected from at least one of triphenylboron, tris(pentafluorophenyl)boron. The specific structure is as follows:

[0060]

[0061] Preferably, the heteroaryl-substituted borane is selected from diethyl(3-pyridyl)-boron. The specific structure is as follows:

[0062]

[0063] Preferably, the organoborate ester is selected from at least one of diethylmethoxyboron, diisopropoxy-methylboron, ethylboronic acid pinacol ester, cyclohexylboronic acid pinacol ester, trimethyltrioxoboroxane, triphenyltrioxoboroxane, C1-C10 trialkyl borate, triphenyl borate. The specific structure is as follows:

[0064]

[0065] wherein n is in the range of 0≤n≤9, and n is an integer.

[0066] Preferably, the dihydrocarbyl boron halide is selected from at least one of dimethylboron bromide, di(tritolyl)boron fluoride, diethylboron chloride.

[0067]

[0068] Preferably, the boron trihalide is at least one of boron trifluoride, boron trichloride, boron tribromide, boron triiodide.

[0069] Preferably, the organoaluminum compound is selected from at least one of the following structural formulae:

[0070]

[0071] wherein Q1, Q2, Q3are independently selected from at least one of Cl, Br, OR13, SR13, N(R13)2; and each R13is independently selected from at least one of C1-C8 alkyl, phenyl, pentafluorophenyl.

[0072] Preferably, the urea and thiourea have the following structural formulae, respectively:

[0073]

[0074] wherein R14, R15are independently selected from at least one of H, C1-C16 alkyl, phenyl, trifluoromethyl-substituted phenyl, benzyl, heteroatom-substituted C1-C16 alkyl, heteroatom-substituted phenyl, heteroatom-substituted benzyl, C3-C16 heterocyclyl, heteroatom-substituted C3-C16 heterocyclyl, C5-C16 heteroaryl, heteroatom-substituted C5-C16 heteroaryl.

[0075] Specifically, the heteroatom is selected from at least one of B, N, O, Si, P, S; and the heteroatom in the heterocyclyl and heteroaryl is selected from at least one of B, N, O, Si, P, S.

[0076] Preferably, the carboxamide has the following structural formula:

[0077]

[0078] R16, R17 each independently represents at least one of H, C1-C16 alkyl, phenyl, trifluoromethyl-substituted phenyl, benzyl, heteroatom-substituted C1-C16 alkyl, heteroatom-substituted phenyl, heteroatom-substituted benzyl, C3-C16 heterocyclyl, heteroatom-substituted C3-C16 heterocyclyl, C5-C16 heteroaryl, heteroatom-substituted C5-C16 heteroaryl.

[0079] Specifically, the heteroatom is selected from at least one of B, N, O, Si, P, S; the heteroatom in the heterocyclyl and heteroaryl is selected from at least one of B, N, O, Si, P, S.

[0080] Further preferably, the Lewis acid is selected from at least one of the following compounds: Zinc bromide.

[0081] Preferably, the molar ratio of the ionic compound and the epoxide compound is (0.001-1):10.

[0082] Further preferably, the molar ratio of the ionic compound and the epoxide compound is (0.002-0.1):10.

[0083] Preferably, the molar ratio of the ionic compound, the acid and the epoxide compound is (0.001-1):(0-1):10.

[0084] Further preferably, the molar ratio of the ionic compound, the acid and the epoxide compound is (0.001-0.1):(0.001-0.05):10.

[0085] Preferably, the reaction temperature of the catalytic cycloaddition reaction is 40-160°C.

[0086] Further preferably, the reaction temperature of the catalytic cycloaddition reaction is 50-150°C.

[0087] Preferably, the reaction pressure of the catalytic cycloaddition reaction is 0.1-5 MPa.

[0088] Further preferably, the reaction pressure of the catalytic cycloaddition reaction is 0.2-2 MPa.

[0089] Preferably, the reaction time of the catalytic cycloaddition reaction is 0.2-30 h.

[0090] Further preferably, the reaction time of the catalytic cycloaddition reaction is 0.3-18 h.

[0091] Further more preferably, the reaction time of the catalytic cycloaddition reaction is 0.5-3 h.

[0092] Preferably, the epoxy compound is selected from at least one of the following structural formulae:

[0093]

[0094] wherein n, m, x, y, z are integers, and the value range of n, m, x, y, z is: 0≤n≤19, 0≤m≤15, 0≤x≤12, 1≤y≤11, 1≤z≤10.

[0095] Preferably, the epoxy compound is selected from at least one of the following structural formulae:

[0096]

[0097] In a third aspect, the application provides the above method for synthesizing cyclic carbonate.

[0098] The anion in the ionic compound of the application has suitable nucleophilicity and leaving property, and it can be combined with other active positive ions and metal ions to form a catalytic system with good activity, low or no halogen, and good solubility. In addition, the catalytic system is particularly suitable for catalyzing the synthesis of cyclic carbonate.

[0099] Meanwhile, the catalytic method for synthesizing cyclic carbonate of the application not only has suitable catalytic system, simple preparation, low cost, rich structure, wide application range of epoxy compounds, etc., but also can efficiently synthesize cyclic carbonate with high conversion rate, high chemical selectivity under the conditions of no solvent, low or no halogen, small amount of catalyst, and mild reaction conditions. In addition, the method has the advantages of easy separation and purification of products.

[0100] Specifically:

[0101] (1) The raw materials required for the synthesis of the ionic compound in the present application are abundant in source and easy to obtain, and the preparation process is simple. The reaction types involve the reaction of iso(thio)cyanate and amine or (thio)alcohol, the reaction of (thio)amide synthesis, the salt formation reaction of (thio)urea / (thio)amide, cation exchange reaction, etc. Therefore, the structure of the ionic compound is extremely rich, the cost is low, and the structure of the molecule can be flexibly designed according to the reaction conditions, the structure of the epoxide compound or the substituent group, so as to achieve the best catalytic activity and chemical selectivity.

[0102] (2) The present application relates to a wide variety of single-component and two-component catalysts, which have a wide adjustment and optimization window. Through the combination of various ionic compounds and Lewis acids, the catalytic activity can be more flexibly adjusted and optimized according to the structure and activity characteristics of different epoxide compounds.

[0103] (3) The ionic compound and most of the acids used in the present application have good solubility, and the ionic compound also has a certain solubilizing effect on carbon dioxide, so as to further improve the activity of the cycloaddition reaction, and the reaction can be carried out under solvent-free or less solvent conditions, without the need for solvent separation process. At the same time, the high efficiency and high selectivity of the catalytic method make the cyclocarbonate yield high, the by-products are few, and the product is easy to separate and purify, thereby improving the production efficiency.

[0104] (4) The catalytic method of the present application shows excellent catalytic activity and high chemical selectivity in the cycloaddition reaction of CO2 and epoxide compounds, avoids the use of ultrahigh pressure and high temperature conditions, can efficiently synthesize cyclocarbonates under relatively mild conditions, further reduces or removes the use of co-catalysts (halide salts), reduces the safety hazard, prolongs the service life of the equipment, and is suitable for industrial production.

[0105] (5) For the epoxide cyclohexane reactant, the catalytic synthesis method of the present application can also achieve the effect of preparing cyclocarbonate product with high conversion rate and high selectivity under the conditions of less catalyst dosage, no halogen, relatively mild reaction conditions and shorter reaction time. BRIEF DESCRIPTION OF DRAWINGS

[0106] Figure 1 H NMR spectrum of the cyclocarbonate synthesized for Example 3. 1 H NMR spectrum.

[0107] Figure 2 H NMR spectrum of the ionic compound I13 synthesized for Example 24. 1 H NMR spectrum. DETAILED DESCRIPTION

[0108] The content of the present application is further described in detail through specific examples.

[0109] The conversion rate of the epoxy compound and the product composition in the following examples are directly measured or analyzed by a Bruker AV400 liquid nuclear magnetic resonance instrument, and the solvent is deuterated chloroform; the oxygen-free condition in the examples is achieved by replacing the inert gas (such as nitrogen) through vacuum extraction; the room temperature in the examples refers to 20-25℃; the selectivity greater than 99% in the examples means that the selectivity is 99.1-99.9%; and "vacuum extraction" in the examples means that the extraction is performed in a reduced pressure environment.

[0110] The specific structural formula and abbreviation of the raw material used in the embodiment of the present application are shown as follows:

[0111] The epoxy compound as a reactant:

[0112] The Lewis acid:

[0113]

[0114] The ionic compound:

[0115]

[0116] The preparation method of the ionic compounds I1-I13 in the present application is respectively described in the embodiments 1, 3, 5, 6, 7, 8, 9, 10, 11, 21, 22, 23 and 24.

[0117] It should be further noted that the structure of the cyclic carbonate P1 prepared by the catalytic addition reaction of ethylene oxide (EO) is as follows: The structure of the cyclic carbonate prepared by the catalytic addition reaction of propylene oxide (PO) is as follows:

[0118] The structure of the cyclic carbonate prepared by the catalytic addition reaction of 1,2-epoxy cyclohexane (CHO) is as follows:

[0119] Embodiment 1

[0120] The embodiment provides a preparation method of an ionic compound I1, which comprises the following steps.

[0121] In a 50 mL glass reactor, 2 mmol of diphenyl urea, a methanol solution containing 2 mmol of tetrabutylammonium hydroxide (the mass fraction of tetrabutylammonium hydroxide is 40%, and the solvent is methanol) and 5 mL of tetrahydrofuran solvent are sequentially added, and the reactor is sealed; the reaction is stirred at 60℃ for 1 h; and then vacuum drying is continuously performed at 80℃ for 1 h to remove the solvent and generated water, so as to obtain the ionic compound I1 (the yield is 100%).

[0122] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, and the method comprises the following steps:

[0123] (1) Under anhydrous and anaerobic conditions, 1 mmol of ionic compound I1 is added into a 100 mL stainless steel autoclave, and the autoclave is cooled to-20 DEG C through a liquid nitrogen-ethanol bath, then 100 mmol of ethylene oxide (EO) is added, the autoclave is sealed, and the autoclave is restored to room temperature (20-25 DEG C);

[0124] (2) 1 MPa of CO2 gas is continuously filled into the autoclave, the autoclave is sealed, a magnetic stirrer is started, and the reaction is kept at 140 DEG C in an aluminum heating block for 24 h;

[0125] After the reaction is completed, the autoclave is cooled through an ice-water bath, the residual pressure is released, and the cyclic carbonate P1 product (ethylene carbonate) is obtained through vacuum distillation.

[0126] Through H NMR test analysis, the conversion rate of the ethylene oxide EO is 52%, and the selectivity of the cyclic carbonate P1 is greater than 99%. 1 H NMR test analysis, the conversion rate of the ethylene oxide EO is 52%, and the selectivity of the cyclic carbonate P1 is greater than 99%.

[0127] Example 2

[0128] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, and the method comprises the following steps:

[0129] (1) Under anhydrous and anaerobic conditions, 1 mmol of ionic compound I1, 1 mmol of diphenylthiourea (TU1) are added into a 100 mL stainless steel autoclave, and the autoclave is cooled to-20 DEG C through a liquid nitrogen-ethanol bath, then 100 mmol of ethylene oxide (EO) is added, the autoclave is sealed, and the autoclave is restored to room temperature;

[0130] (2) 1 MPa of CO2 gas is continuously filled into the autoclave, the autoclave is sealed, a magnetic stirrer is started, and the reaction is kept at 140 DEG C in an aluminum heating block for 16 h;

[0131] After the reaction is completed, the autoclave is cooled through an ice-water bath, the residual pressure is released, and the cyclic carbonate P1 product (ethylene carbonate) is obtained through vacuum distillation.

[0132] Through H NMR test analysis, the conversion rate of the ethylene oxide EO is 52%, and the selectivity of the cyclic carbonate P1 is greater than 99%. 1 H NMR test analysis, the conversion rate of the ethylene oxide EO is 52%, and the selectivity of the cyclic carbonate P1 is greater than 99%.

[0133] Example 3

[0134] The embodiment provides a preparation method of ionic compound I2, and the method comprises the following steps:

[0135] (1) In a 50 mL glass reactor, 4 mmol of aniline, 4 mmol of cyclohexyl isocyanate and 5 mL of toluene solvent were sequentially added, the reactor was sealed, and the reaction was carried out at room temperature for 24 h; after the reaction was completed, the crude product was washed with toluene, the solid was collected, and vacuum drying was performed to obtain 1-cyclohexyl-3-phenyl urea (yield: 94%);

[0136] (2) In a 50 mL glass reactor, 2 mmol of 1-cyclohexyl-3-phenyl urea, a methanol solution containing 2 mmol of tetrabutylammonium hydroxide (the mass fraction of tetrabutylammonium hydroxide was 40%, and the solvent was methanol), and 5 mL of tetrahydrofuran solvent were sequentially added, the reactor was sealed, and the reaction was carried out at 60°C for 1 h; vacuum drying was continuously performed at 80°C for 1 h to remove the solvent and generated water, and an ionic compound I2 was obtained (yield: 100%).

[0137] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, and the method comprises the following steps:

[0138] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of the ionic compound I2, a tetrahydrofuran solution containing 0.2 mmol of triethyl boron (TEB) (the concentration of TEB was 1 mol / L, and the solvent was tetrahydrofuran) were added into a 100 mL stainless steel autoclave, and then 100 mmol of propylene oxide (PO) was added, the reactor was sealed, and stirring was uniformly performed;

[0139] (2) CO2 gas with a pressure of 1 MPa was filled into the reactor, the reactor was sealed, a magnetic stirrer was started, and constant temperature reaction was performed in an aluminum heating block at 100°C for 2 h;

[0140] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and reduced pressure distillation was performed to obtain a cyclic carbonate P2 product (i.e., propylene carbonate).

[0141] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and reduced pressure distillation was performed to obtain a cyclic carbonate P2 product (i.e., propylene carbonate). 1 H NMR test analysis showed that the conversion rate of propylene oxide PO was 79%, and the selectivity of the cyclic carbonate P2 was greater than 99%.

[0142] Embodiment 4

[0143] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, and the method comprises the following steps:

[0144] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of the ionic compound I2, a tetrahydrofuran solution containing 0.2 mmol of triethyl boron (TEB) (the concentration of TEB was 1 mol / L, and the solvent was tetrahydrofuran) were added into a 100 mL stainless steel autoclave, and then 100 mmol of propylene oxide (PO) was added, the reactor was sealed, and stirring was uniformly performed;

[0145] (2) 1 MPa CO2 gas was filled into the reaction kettle, the reaction kettle was sealed, the magnetic stirrer was started, and the reaction was kept constant at 100°C in the aluminum heating block for 3 h;

[0146] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and vacuum distillation was performed to obtain the cyclic carbonate P3 product (i.e., hexahydrobenzo[D][1,3]dioxolane-2-one).

[0147] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and vacuum distillation was performed to obtain the cyclic carbonate P3 product (i.e., hexahydrobenzo[D][1,3]dioxolane-2-one). 1 H NMR test analysis showed that the conversion rate of the epoxide cyclohexane CHO was 97%, and the selectivity of the cyclic carbonate P3 was 94%.

[0148] Example 5

[0149] The present example provides a method for preparing an ionic compound I3, comprising the following steps:

[0150] In a 50 mL glass reaction bottle, 2 mmol of diphenylthiourea, a methanol solution containing 2 mmol of tetrabutylammonium hydroxide (the mass fraction of tetrabutylammonium hydroxide is 40%, and the solvent is methanol), and 5 mL of tetrahydrofuran solvent were sequentially added, the reaction bottle was sealed, and stirring was performed at 60°C for 1 h. Vacuum drying was continued at 80°C for 1 h to remove the solvent and generated water, thereby obtaining the ionic compound I3 (yield: 100%).

[0151] The present example provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0152] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of the ionic compound I3, a tetrahydrofuran solution containing 0.2 mmol of TEB (the concentration of TEB is 1 mol / L, and the solvent is tetrahydrofuran) was added to a 100 mL stainless steel autoclave, 100 mmol of PO was further added, the reaction kettle was sealed, and stirring was performed uniformly;

[0153] (2) 1 MPa CO2 gas was filled into the reaction kettle, the reaction kettle was sealed, the magnetic stirrer was started, and the reaction was kept constant at 100°C in the aluminum heating block for 1.5 h;

[0154] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and vacuum distillation was performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0155] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and vacuum distillation was performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate). 1 H NMR test analysis showed that the conversion rate of the epoxide cyclohexane CHO was 97%, and the selectivity of the cyclic carbonate P3 was 94%.

[0156] Example 6

[0157] The present example provides a method for preparing an ionic compound I4, comprising the following steps:

[0158] (1) In a 50 mL glass reaction flask, 4 mmol of phenylisocyanate, 8 mmol of selenium powder, and 5 mL of toluene solvent were added sequentially. The flask was sealed and reacted at 50 °C for 12 h. The unreacted selenium powder was filtered off, and 4 mmol of aniline was added. The reaction was continued at 50 °C for 24 h. After the reaction was completed, the crude product was washed with toluene, the solid was collected, and dried under vacuum to obtain diphenylselenourea (yield: 72%).

[0159] (2) In a 50 mL glass reaction flask, 2 mmol of diphenylselenourea, a methanol solution containing 2 mmol of tetrabutylammonium hydroxide (40% by mass, methanol as solvent) and 5 mL of tetrahydrofuran solvent were added sequentially. The reaction flask was sealed and stirred at 60 °C for 1 h. The mixture was then dried under vacuum at 80 °C for 1 h to remove the solvent and the generated water, yielding the ionic compound I4 (yield: 100%).

[0160] This embodiment provides a method for the catalytic synthesis of cyclic carbonates, including the following steps:

[0161] (1) Under anhydrous and oxygen-free conditions, 0.5 mmol of ionic compound I4 and a tetrahydrofuran solution containing 0.2 mmol of TEB (TEB concentration is 1 mol / L) were added to a 100 mL stainless steel autoclave, followed by 100 mmol of PO. The autoclave was then sealed and stirred until homogeneous.

[0162] (2) Introduce 1 MPa of CO2 gas into the reactor, seal the reactor, turn on the magnetic stirrer, and keep the reactor at a constant temperature for 1 hour in an aluminum heating block at 100°C.

[0163] After the reaction was completed, the mixture was cooled in an ice-water bath to release the remaining pressure. The product was then obtained by vacuum distillation, yielding cyclic carbonate P2 (i.e., propylene carbonate).

[0164] through 1 ¹H NMR analysis showed that the conversion rate of propylene oxide (PO) was 100%, and the selectivity of cyclic carbonate (P2) was greater than 99%.

[0165] Example 7

[0166] This embodiment provides a method for preparing an ionic compound I5, including the following steps:

[0167] (1) In a 50 mL glass reaction flask, 4 mmol of N-methylcyclohexylamine, 4 mmol of phenyl isocyanate and 5 mL of toluene solvent were added in sequence. The reaction flask was sealed and reacted at room temperature for 1 h. After the reaction was completed, the crude product was washed with toluene, the solid was collected and dried under vacuum to obtain 1-methylcyclohexyl-3-phenylurea (yield: 92%).

[0168] (2) In a 50 mL glass reaction flask, 2 mmol of 1-methylcyclohexyl-3-phenylurea, 2 mmol of tetraoctylphosphine hydroxide and 5 mL of tetrahydrofuran solvent were added in sequence. The reaction flask was sealed and stirred at 60 °C for 1 h. The mixture was then dried under vacuum at 80 °C for 1 h to remove the solvent and the generated water, thus obtaining the ionic compound I5 (yield: 100%).

[0169] This embodiment provides a method for the catalytic synthesis of cyclic carbonates, including the following steps:

[0170] (1) Under anhydrous and oxygen-free conditions, 0.5 mmol of ionic compound I5 and a tetrahydrofuran solution containing 0.2 mmol of TEB (TEB concentration is 1 mol / L) were added to a 100 mL stainless steel autoclave, followed by 100 mmol of PO. The autoclave was then sealed and stirred until homogeneous.

[0171] (2) Introduce 1 MPa of CO2 gas into the reactor, seal the reactor, turn on the magnetic stirrer, and keep the reactor at a constant temperature for 0.5 h in an aluminum heating block at 100 °C.

[0172] After the reaction was completed, the mixture was cooled in an ice-water bath to release the remaining pressure. The product was then obtained by vacuum distillation, yielding cyclic carbonate P2 (i.e., propylene carbonate).

[0173] through 1 ¹H NMR analysis showed that the conversion rate of propylene oxide (PO) was 78%, and the selectivity of cyclic carbonate (P2) was greater than 99%.

[0174] Example 8

[0175] This embodiment provides a method for preparing the ionic compound I6, including the following steps:

[0176] (1) In a 50 mL glass reaction flask, 4 mmol of aniline, 6 mmol of benzaldehyde, 4 mmol of potassium carbonate, 20 mmol of sulfur powder and 15 mL of water were added in sequence. The reaction flask was sealed and reacted at 100 °C for 24 h. After the reaction was completed, the product was extracted with ethyl acetate, concentrated, recrystallized and dried under vacuum to obtain N-phenylthiobenzamide (yield: 56%).

[0177] (2) In a 50 mL glass reaction flask, add 2 mmol of N-phenylthiobenzamide, 2 mmol of tetraoctylphosphine hydroxide and 5 mL of tetrahydrofuran solvent in sequence, seal the reaction flask, and stir the reaction at 60 °C for 1 h; continue to dry under vacuum at 80 °C for 1 h to remove the solvent and the generated water, and obtain the ionic compound I6 (yield: 100%).

[0178] This embodiment provides a method for the catalytic synthesis of cyclic carbonates, including the following steps:

[0179] (1) Under the conditions of no water and no oxygen, 0.5 mmol of ionic compound I6, a tetrahydrofuran solution containing 0.2 mmol of TEB (the concentration of TEB is 1 mol / L) is added to a 100 mL stainless steel autoclave, then 100 mmol of PO is added, the reaction kettle is sealed, and stirring is uniform;

[0180] (2) 1 MPa of CO2 gas is filled into the reaction kettle, the reaction kettle is sealed, the magnetic stirrer is started, and the reaction is constant temperature reacted at 100℃ in the aluminum heating block for 1 h;

[0181] After the reaction is completed, ice water bath cooling is performed, the remaining pressure is released, and vacuum distillation is performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0182] According to H NMR test analysis, the conversion rate of propylene oxide PO is 93%, and the selectivity of cyclic carbonate P2 is 96%. 1 H NMR test analysis, the conversion rate of propylene oxide PO is 93%, and the selectivity of cyclic carbonate P2 is 96%.

[0183] Example 9

[0184] The present embodiment provides a preparation method of ionic compound I7, comprising the following steps:

[0185] In a 50 mL glass reaction bottle, 4 mmol of N-phenyl ethyl carbamate, 4 mmol of potassium tert-butoxide, 4 mmol of N-ethyl pyridine chloride salt and 10 mL of anhydrous ethanol solvent are sequentially added, the reaction bottle is sealed, and stirring is performed at room temperature for 24 h;

[0186] After the reaction is completed, the filtrate is filtered and dried, the product is washed with toluene, and vacuum drying is performed at 60℃ for 1 h to obtain the ionic compound I7 (yield: 82%).

[0187] The present embodiment provides a method for catalytically synthesizing cyclic carbonate, comprising the following steps:

[0188] (1) Under the conditions of no water and no oxygen, 0.5 mmol of ionic compound I7, a tetrahydrofuran solution containing 0.2 mmol of TEB (the concentration of TEB is 1 mol / L) is added to a 100 mL stainless steel autoclave, then 100 mmol of PO is added, the reaction kettle is sealed, and stirring is uniform;

[0189] (2) 1 MPa of CO2 gas is filled into the reaction kettle, the reaction kettle is sealed, the magnetic stirrer is started, and the reaction is constant temperature reacted at 100℃ in the aluminum heating block for 2 h;

[0190] After the reaction is completed, ice water bath cooling is performed, the remaining pressure is released, and vacuum distillation is performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0191] According to H NMR test analysis, the conversion rate of propylene oxide PO is 93%, and the selectivity of cyclic carbonate P2 is 96%. 1H NMR test analysis showed that the conversion rate of propylene oxide PO was 52%, and the selectivity of cyclic carbonate P2 was 86%.

[0192] Example 10

[0193] The embodiment provides a preparation method of ionic compound I8, which comprises the following steps:

[0194] (1) 4 mmol of phenyl isothiocyanate, 4 mmol of benzyl mercaptan and 5 mL of toluene solvent were sequentially added into a 50 mL glass reaction bottle, the reaction bottle was sealed, and reaction was carried out at room temperature for 24 h; after the reaction was completed, the crude product was cleaned with toluene, the solid was collected, and vacuum drying was performed to obtain N-phenyl benzyl dithiocarbamate (yield: 88%);

[0195] (2) 2 mmol of N-phenyl benzyl dithiocarbamate, 2 mmol of potassium tert-butoxide, 2 mmol of 1,3-dimethylimidazole chloride and 5 mL of anhydrous ethanol solvent were sequentially added into a 50 mL glass reaction bottle, the reaction bottle was sealed, and reaction was carried out at room temperature for 24 h under stirring; after the reaction was completed, filtration was performed, the filtrate was spin-dried, the product was cleaned with toluene, and vacuum drying was performed at 60 DEG C for 1 h to obtain ionic compound I8 (yield: 78%).

[0196] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, which comprises the following steps:

[0197] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I8, a tetrahydrofuran solution containing 0.2 mmol of TEB (the concentration of TEB is 1 mol / L) and 100 mmol of PO were added into a 100 mL stainless steel autoclave, and the reaction kettle was sealed and uniformly stirred;

[0198] (2) 1 MPa of CO2 gas was filled into the reaction kettle, the reaction kettle was sealed, a magnetic stirrer was started, and constant temperature reaction was carried out in an aluminum heating block at 100 DEG C for 1 h;

[0199] After the reaction was completed, ice water bath cooling was performed, the residual pressure was released, and vacuum distillation was performed to obtain cyclic carbonate P2 product (i.e., propylene carbonate).

[0200] After the reaction was completed, ice water bath cooling was performed, the residual pressure was released, and vacuum distillation was performed to obtain cyclic carbonate P2 product (i.e., propylene carbonate). 1 H NMR test analysis showed that the conversion rate of propylene oxide PO was 95%, and the selectivity of cyclic carbonate P2 was 97%.

[0201] Example 11

[0202] The embodiment provides a preparation method of ionic compound I9, which comprises the following steps:

[0203] In a 50 mL glass reaction flask, 2 mmol of acrylurea, 2 mmol of potassium tert-butoxide, and 5 mL of ethanol solvent were added sequentially. The flask was sealed, and the mixture was stirred at 60 °C for 12 h. Then, 2 mmol of tetraoctylammonium chloride was added, and the mixture was stirred at room temperature for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was evaporated to dryness, the product was washed with toluene, and then dried under vacuum at 60 °C for 1 h to obtain the ionic compound I9 (yield: 74%).

[0204] This embodiment provides a method for catalytic synthesis of cyclic carbonates, including the following steps:

[0205] (1) Under anhydrous and oxygen-free conditions, 0.5 mmol of ionic compound I9 and a tetrahydrofuran solution containing 0.2 mmol of TEB (TEB concentration of 1 mol / L) were added to a 100 mL stainless steel autoclave, followed by 100 mmol of PO. The autoclave was then sealed and stirred until homogeneous.

[0206] (2) Introduce 1 MPa of CO2 gas into the reactor, seal the reactor, turn on the magnetic stirrer, and keep the reactor at a constant temperature for 2 hours in an aluminum heating block at 100°C.

[0207] After the reaction was completed, the mixture was cooled in an ice-water bath to release the remaining pressure. The product was then obtained by vacuum distillation, yielding cyclic carbonate P2 (i.e., propylene carbonate).

[0208] through 1 ¹H NMR analysis showed that the conversion rate of propylene oxide (PO) was 84%, and the selectivity of cyclic carbonate (P2) was greater than 99%.

[0209] Example 12

[0210] This embodiment provides a method for catalytic synthesis of cyclic carbonates, including the following steps:

[0211] (1) Under anhydrous and oxygen-free conditions, 0.5 mmol of ionic compound I2 and 0.2 mmol of triphenylborone (TPB) were added to a 100 mL stainless steel autoclave, followed by 100 mmol of PO. The autoclave was then sealed and stirred until homogeneous.

[0212] (2) Introduce 1 MPa of CO2 gas into the reactor, seal the reactor, turn on the magnetic stirrer, and keep the reactor at a constant temperature for 0.5 h in an aluminum heating block at 100 °C.

[0213] After the reaction was completed, the mixture was cooled in an ice-water bath to release the remaining pressure. The product was then obtained by vacuum distillation, yielding cyclic carbonate P2 (i.e., propylene carbonate).

[0214] through 1 ¹H NMR analysis showed that the conversion rate of propylene oxide (PO) was 100%, and the selectivity of cyclic carbonate (P2) was greater than 99%.

[0215] Example 13

[0216] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0217] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I2 and 0.2 mmol of TPB are added into a 100-mL stainless steel autoclave, 100 mmol of PO is further added, the autoclave is sealed, and stirring is performed uniformly;

[0218] (2) 1 MPa of CO2 gas is filled into the autoclave, the autoclave is sealed, a magnetic stirrer is started, and constant temperature reaction is performed in an aluminum heating block at 50 DEG C for 5 h;

[0219] After the reaction is completed, ice water bath cooling is performed, the residual pressure is released, and pressure reduction distillation is performed, so that a cyclic carbonate P2 product (i.e., propylene carbonate) is obtained.

[0220] Through H NMR test analysis, the conversion rate of propylene oxide PO is 97%, and the selectivity of the cyclic carbonate P2 is greater than 99%. 1 H NMR test analysis, the conversion rate of propylene oxide PO is 97%, and the selectivity of the cyclic carbonate P2 is greater than 99%.

[0221] Example 14

[0222] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0223] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I2 and 0.2 mmol of TPB are added into a 100-mL stainless steel autoclave, 100 mmol of PO is further added, the autoclave is sealed, and stirring is performed uniformly;

[0224] (2) 1 MPa of CO2 gas is filled into the autoclave, the autoclave is sealed, a magnetic stirrer is started, and constant temperature reaction is performed in an aluminum heating block at 50 DEG C for 5 h;

[0225] After the reaction is completed, ice water bath cooling is performed, the residual pressure is released, and pressure reduction distillation is performed, so that a cyclic carbonate P2 product (i.e., propylene carbonate) is obtained.

[0226] Through H NMR test analysis, the conversion rate of propylene oxide PO is 97%, and the selectivity of the cyclic carbonate P2 is greater than 99%. 1 H NMR test analysis, the conversion rate of propylene oxide PO is 97%, and the selectivity of the cyclic carbonate P2 is greater than 99%.

[0227] Example 15

[0228] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0229] (1) Under the conditions of no water and no oxygen, 0.5 mmol of ionic compound I2 and 0.05 mmol of TPB were added into a 100 mL stainless steel autoclave, 100 mmol of PO was added, the reactor was sealed, and stirring was performed uniformly;

[0230] (2) 2 MPa of CO2 gas was filled into the reactor, the reactor was sealed, a magnetic stirrer was started, and constant temperature reaction was performed at 100°C in an aluminum heating block for 2 h;

[0231] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and reduced pressure distillation was performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0232] According to H NMR test analysis, the conversion rate of propylene oxide PO was 100%, and the selectivity of cyclic carbonate P2 was greater than 99%. 1 H NMR test analysis, the conversion rate of propylene oxide PO was 100%, and the selectivity of cyclic carbonate P2 was greater than 99%.

[0233] Example 16

[0234] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0235] (1) Under the conditions of no water and no oxygen, 0.05 mmol of ionic compound I2 and 0.05 mmol of TPB were added into a 100 mL stainless steel autoclave, 100 mmol of PO was added, the reactor was sealed, and stirring was performed uniformly;

[0236] (2) 1 MPa of CO2 gas was filled into the reactor, the reactor was sealed, a magnetic stirrer was started, and constant temperature reaction was performed at 100°C in an aluminum heating block for 24 h;

[0237] After the reaction was completed, ice water bath cooling was performed, the remaining pressure was released, and reduced pressure distillation was performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0238] According to H NMR test analysis, the conversion rate of propylene oxide PO was 100%, and the selectivity of cyclic carbonate P2 was greater than 99%. 1 H NMR test analysis, the conversion rate of propylene oxide PO was 100%, and the selectivity of cyclic carbonate P2 was greater than 99%.

[0239] Example 17

[0240] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0241] (1) Under the conditions of no water and no oxygen, 0.125 mmol of ionic compound I2 and 0.0125 mmol of TPB were added into a 100 mL stainless steel autoclave, 25 mmol of PO was added, the reactor was sealed, and stirring was performed uniformly;

[0242] (2) The reaction kettle is filled with 0.2 MPa of CO2 gas, the reaction kettle is sealed, the magnetic stirrer is started, and the reaction is kept constant at 100°C in the aluminum heating block for 18 h;

[0243] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained through vacuum distillation.

[0244] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained through vacuum distillation. 1 The conversion rate of propylene oxide PO is 100%, and the selectivity of cyclic carbonate P2 is greater than 99% through H NMR test analysis.

[0245] Example 18

[0246] The embodiment provides a method for catalytically synthesizing cyclic carbonate, comprising the following steps:

[0247] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I2 and 0.05 mmol of triisobutylaluminum (Bu3Al) are added to a 100 mL stainless steel autoclave, 100 mmol of PO is added, the reaction kettle is sealed, and stirring is uniform; i (2) The reaction kettle is filled with 1 MPa of CO2 gas, the reaction kettle is sealed, the magnetic stirrer is started, and the reaction is kept constant at 100°C in the aluminum heating block for 1 h;

[0248] (2) The reaction kettle is filled with 1 MPa of CO2 gas, the reaction kettle is sealed, the magnetic stirrer is started, and the reaction is kept constant at 100°C in the aluminum heating block for 1 h;

[0249] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained through vacuum distillation.

[0250] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained through vacuum distillation. 1 The conversion rate of propylene oxide PO is 100%, and the selectivity of cyclic carbonate P2 is greater than 99% through H NMR test analysis.

[0251] Example 19

[0252] The embodiment provides a method for catalytically synthesizing cyclic carbonate, comprising the following steps:

[0253] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I2 and 0.05 mmol of triisobutylaluminum (Bu3Al) are added to a 100 mL stainless steel autoclave, 100 mmol of PO is added, the reaction kettle is sealed, and stirring is uniform;

[0254] (2) The reaction kettle is filled with 1 MPa of CO2 gas, the reaction kettle is sealed, the magnetic stirrer is started, and the reaction is kept constant at 100°C in the aluminum heating block for 1 h;

[0255] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained by distillation under reduced pressure.

[0256] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained by distillation under reduced pressure. 1 H NMR test analysis shows that the conversion rate of propylene oxide PO is 100%, and the selectivity of cyclic carbonate P2 is greater than 99%.

[0257] Example 20

[0258] The present embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0259] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I2 and 0.05 mmol of ZnBr2 are added to a 100 mL stainless steel autoclave, and then 100 mmol of PO is added, the reaction kettle is sealed, and stirring is performed uniformly;

[0260] (2) 1 MPa of CO2 gas is filled into the reaction kettle, the reaction kettle is sealed, the magnetic stirrer is turned on, and constant temperature reaction is performed at 150°C in the aluminum heating block for 0.5 h.

[0261] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained by distillation under reduced pressure.

[0262] After the reaction is completed, the ice water bath is cooled, the remaining pressure is released, and the product of cyclic carbonate P2 (i.e., propylene carbonate) is obtained by distillation under reduced pressure. 1 H NMR test analysis shows that the conversion rate of propylene oxide PO is 100%, and the selectivity of cyclic carbonate P2 is greater than 99%.

[0263] Example 21

[0264] The present embodiment provides a method for preparing ionic compound I10, comprising the following steps:

[0265] (1) In a 50 mL glass reaction bottle, 4 mmol of aniline, 4 mmol of allyl isothiocyanate, and 5 mL of toluene solvent are sequentially added, the reaction bottle is sealed, and reaction is performed at room temperature for 48 h. After the reaction is completed, the crude product is washed with toluene, the solid is collected, and vacuum drying is performed to obtain 1-allyl-3-phenyl thiourea (yield: 94%).

[0266] (2) In a 50 mL glass reaction bottle, 3 mmol of 1-allyl-3-phenyl thiourea, and a tetrahydrofuran solution containing 3 mmol of 9-borabicyclo[3.3.1]nonane (the concentration of 9-borabicyclo[3.3.1]nonane is 0.5 mol / L) are sequentially added, the reaction bottle is sealed, and reaction is performed at room temperature for 4 h. After the reaction is completed, the solvent is spin-dried, the solid product is washed with n-hexane, and vacuum drying is performed to obtain a borane-substituted thiourea compound TUB1 (yield: 97%), the structure of which is shown below:

[0267]

[0268] (3) In a 50 mL glass reaction bottle, 2 mmol of TUB1, 2 mmol of tetrabutylammonium hydroxide and 5 mL of tetrahydrofuran solvent were sequentially added, the reaction bottle was sealed, and the reaction was stirred at 60°C for 1 h; vacuum drying was continued at 80°C for 1 h to remove the solvent and generated water, and an ionic compound I10 was obtained (yield: 100%).

[0269] The embodiment provides a method for catalytically synthesizing a cyclic carbonate, comprising the following steps:

[0270] (1) Under anhydrous and anaerobic conditions, 0.02 mmol of an ionic compound I10 containing a borane substituent was added to a 100 mL stainless steel autoclave, and 100 mmol of PO was added, the reaction kettle was sealed, and stirring was performed uniformly;

[0271] (2) 1 MPa of CO2 gas was filled into the reaction kettle, the reaction kettle was sealed, a magnetic stirrer was started, and constant temperature reaction was performed in an aluminum heating block at 150°C for 24 h;

[0272] After the reaction was completed, an ice water bath was used for cooling, the remaining pressure was released, and reduced pressure distillation was performed to obtain a cyclic carbonate P2 product (i.e., propylene carbonate).

[0273] Through 1 H NMR test analysis shows that the conversion rate of propylene oxide PO is 100%, and the selectivity of the cyclic carbonate P2 is greater than 99%.

[0274] Embodiment 22

[0275] The embodiment provides a preparation method of an ionic compound I11, comprising the following steps:

[0276] (1) In a 50 mL glass reaction bottle, 4 mmol of propylene alcohol, 4 mmol of phenyl isocyanate and 5 mL of toluene solvent were sequentially added, the reaction bottle was sealed, and reaction was performed at room temperature for 12 h. After the reaction was completed, the crude product was washed with n-hexane, the solid was collected, and vacuum drying was performed to obtain N-phenyl allyl carbamate (yield: 86%).

[0277] (2) In a 50 mL glass reaction bottle, 3 mmol of N-phenyl allyl carbamate, a tetrahydrofuran solution containing 3 mmol of 9-borabicyclo[3.3.1]nonane (the concentration of 9-borabicyclo[3.3.1]nonane is 0.5 mol / L) were sequentially added, the reaction bottle was sealed, and reaction was performed at room temperature for 4 h. After the reaction was completed, the solvent was spin-dried, the solid product was washed with n-hexane, and vacuum drying was performed to obtain a borane substituent-containing carbamate compound CB1 (yield: 97%), and the structure is as shown below:

[0278]

[0279] (3) In a 50 mL glass reaction flask, add 2 mmol of CB1, 2 mmol of tetrabutylammonium hydroxide and 5 mL of tetrahydrofuran solvent in sequence, seal the reaction flask, and stir the reaction at 60 °C for 1 h; continue to dry under vacuum at 80 °C for 1 h to remove the solvent and the generated water, and obtain the ionic compound I11 (yield: 100%).

[0280] This embodiment provides a method for catalytic synthesis of cyclic carbonates, including the following steps:

[0281] (1) Under anhydrous and oxygen-free conditions, 0.01 mmol of ionic compound I11 containing borane substituents was added to a 100 mL stainless steel autoclave, followed by 100 mmol of PO. The autoclave was then sealed and stirred until homogeneous.

[0282] (2) Introduce 1 MPa of CO2 gas into the reactor, seal the reactor, turn on the magnetic stirrer, and keep the reactor at a constant temperature of 150°C for 12 hours in an aluminum heating block.

[0283] After the reaction was completed, the mixture was cooled in an ice-water bath to release the remaining pressure. The product was then obtained by vacuum distillation, yielding cyclic carbonate P2 (i.e., propylene carbonate).

[0284] through 1 ¹H NMR analysis showed that the conversion rate of propylene oxide (PO) was 100%, and the selectivity of cyclic carbonate (P2) was greater than 99%.

[0285] Example 23

[0286] This embodiment provides a method for preparing the ionic compound I12, including the following steps:

[0287] In a 50 mL glass reactor, 2 mmol of 4-phenyloxazolidine-2-one, a methanol solution containing 2 mmol of tetrabutylammonium hydroxide (40% by mass, methanol as solvent) and 5 mL of tetrahydrofuran solvent were added sequentially. The reactor was then sealed. The reaction was stirred at 60 °C for 1 h. The mixture was then dried under vacuum at 80 °C for 1 h to remove the solvent and the generated water, yielding the ionic compound I12 (yield: 100%).

[0288] This embodiment provides a method for catalytic synthesis of cyclic carbonates, including the following steps:

[0289] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I12, a tetrahydrofuran solution containing 0.2 mmol of triethylboron (TEB) (the concentration of TEB is 1 mol / L, and the solvent is tetrahydrofuran) is added to a 100 mL stainless steel autoclave, then 100 mmol of propylene oxide (PO) is added, the reaction kettle is sealed, and stirring is uniform;

[0290] (2) 1 MPa of CO2 gas is filled into the reaction kettle, the reaction kettle is sealed, the magnetic stirrer is started, and the constant temperature reaction is carried out at 100°C in the aluminum heating block for 2 h;

[0291] After the reaction is completed, ice water bath cooling is performed, the remaining pressure is released, and vacuum distillation is performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0292] Through 1 H NMR test analysis, the conversion rate of propylene oxide PO is 61%, and the selectivity of cyclic carbonate P2 is greater than 99%.

[0293] Example 24

[0294] The present embodiment provides a preparation method of ionic compound I13, comprising the following steps:

[0295] In a 50 mL glass reaction bottle, 4 mmol of N-phenyl methyl carbamate, a methanol solution containing 4 mmol of tetrabutylammonium hydroxide (the mass fraction of tetrabutylammonium hydroxide is 40%, and the solvent is methanol), and 5 mL of tetrahydrofuran solvent are sequentially added, the reaction bottle is sealed, stirring is performed at 60°C for 1 h, vacuum drying is continuously performed at 80°C for 1 h, and the solvent and generated water are removed to obtain ionic compound I13 (the yield is 100%), and the test results of nuclear magnetic resonance hydrogen spectrum are as shown in Figure 2 .

[0296] The present embodiment provides a method for catalytically synthesizing cyclic carbonate, comprising the following steps:

[0297] (1) Under anhydrous and anaerobic conditions, 0.5 mmol of ionic compound I13, a tetrahydrofuran solution containing 0.2 mmol of TEB (the concentration of TEB is 1 mol / L) is added to a 100 mL stainless steel autoclave, then 100 mmol of PO is added, the reaction kettle is sealed, and stirring is uniform;

[0298] (2) 1 MPa of CO2 gas is filled into the reaction kettle, the reaction kettle is sealed, the magnetic stirrer is started, and the constant temperature reaction is carried out at 100°C in the aluminum heating block for 2 h;

[0299] After the reaction is completed, ice water bath cooling is performed, the remaining pressure is released, and vacuum distillation is performed to obtain the cyclic carbonate P2 product (i.e., propylene carbonate).

[0300] through 1 ¹H NMR analysis showed that the conversion rate of propylene oxide (PO) was 100%, and the selectivity of cyclic carbonate (P2) was 98%.

[0301] Test Result Analysis

[0302] Example 3 Synthesized cyclic carbonate 1 H NMR spectrum, such as Figure 1 As shown.

[0303] Depend on Figure 1 It can be seen that Example 3 can successfully prepare the corresponding cyclic carbonate product P2 (i.e., propylene carbonate). Taking the original data of the product of Example 3 as an example, the corresponding cyclic carbonate product can be prepared by cycloaddition reaction under the catalytic system of the present invention, and the structure of the product can be determined by NMR testing, and the conversion rate and selectivity of the reaction can be obtained by analysis.

[0304] Example 24 Synthesized ionic compound I13 1 H NMR spectrum, such as Figure 2 As shown.

[0305] Depend on Figure 2 It can be seen that the NH hydrogen chemical shift signal of methyl N-phenylcarbamate completely disappeared, indicating that the proton was completely removed. Furthermore, the remaining hydrogen chemical shift signals and integral values ​​are consistent with the target structure (I13), proving that the ionic compound I13 was successfully synthesized.

[0306] The preparation process parameters and results of the catalytic synthesis of cyclic carbonates in Examples 1 to 24 are compared in Table 1.

[0307] Table 1

[0308]

[0309]

[0310] Note: The “Amount of Ionic Compound” in Table 1 represents the molar ratio of ionic compound to epoxy compound, in mol%.

[0311] "Acid dosage" refers to the molar ratio of acid to reactants, expressed in mol%.

[0312] "Selectivity > 99%" means that the selectivity is 99.1% to 99.9%.

[0313] "Conversion rate" is calculated based on the change in the epoxide compound before and after the reaction; "selectivity" refers to the selectivity of the cyclic carbonate product.

[0314] As shown in Table 1, for the process of catalytic synthesis of cyclic carbonate, in the catalytic reaction system containing ionic compound, not only can be applied to different types of epoxide, but also can realize the effect of high conversion rate (52%~100%) and high selectivity (86%~99.9%) under the condition of no halogen or low halogen, and small amount of catalyst. In addition, according to the results of Example 1 and Example 2, the use of ionic compound and Lewis acid (with activated epoxide) can further improve the catalytic activity and reaction efficiency of the reaction system.

[0315] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are included in the protection scope of the present application.

Claims

1. A process for the catalytic synthesis of cyclic carbonates, characterized in that, The method comprises the following steps: The catalytic cycloaddition reaction is carried out by mixing the epoxide compound, carbon dioxide and the catalyst to obtain the cyclic carbonate; wherein the catalyst comprises an ionic compound, and the structure of the ionic compound is shown in formula (III) or formula (IV): or ; Wherein, X is selected from one of O, S, Se; Y is selected from one of C(R3)2, NR3, O, S; R1 is selected from one of phenyl, tolyl, benzyl, C1-C20 chain alkyl, C1-C8 chain alkyl substituted by borane substituent; R2 is selected from one of phenyl, tolyl, benzyl, C3-C8 cycloalkyl, C1-C20 chain alkyl, C1-C8 chain alkyl substituted by borane substituent; each R3 is independently selected from one of H, C1-C20 chain alkyl; R4 is selected from one of H, phenyl, tolyl, benzyl; in formula (IV), R4 is directly connected to any carbon atom on the ring, and the value of L is 0 or 1; M is selected from , , one of the following: Wherein, R5-R12 are independently selected from one of C1-C8 alkyl, benzyl; Z is selected from one of N, P.

2. The process for the catalytic synthesis of cyclic carbonates according to claim 1, characterized by the fact that: The ionic compound is replaced by any one of the following structural formulae: 。 3. The process for the catalytic synthesis of cyclic carbonates according to claim 1, characterized by the fact that, The catalyst further comprises a Lewis acid; the Lewis acid is selected from at least one of trialkyl borane, aryl-substituted borane, heteroaryl-substituted borane, organic borate, dialkyl boron halide, boron trihalide, organic aluminum compound, metal halide, thiourea; The trialkyl borane is selected from at least one of trimethyl boron, triethyl boron, triisopropyl boron, tri-n-butyl boron, tri-sec-butyl boron, B-isopinocampyl-9-borabicyclo[3.3.1]nonane; The aryl-substituted borane is selected from at least one of triphenyl borane, tris(pentafluorophenyl)boron; The heteroaryl-substituted borane is selected from diethyl(3-pyridyl)-boron; The organic borate is selected from at least one of diethyl methoxy boron, diisopropoxy methyl boron, ethyl boron pinacol ester, cyclohexyl boron pinacol ester, trimethyl cyclotriboroxane, triphenyl cyclotriboroxane, C1-C10 trialkyl borate, triphenyl borate; The dialkyl boron halide is selected from at least one of dimethyl boron bromide, di(mesityl) boron fluoride, diethyl boron chloride; The boron trihalide is at least one of boron trifluoride, boron trichloride, boron tribromide, boron triiodide; The organic aluminum compound is selected from at least one of the following structural formulae: ； Wherein, Q1, Q2, Q3 are independently selected from at least one of Cl, Br, OR13, SR13, N(R13)2; R13 is independently selected from at least one of C1-C8 alkyl, phenyl, pentafluorophenyl; The metal halide is a metal halide salt, and the metal in the metal halide is selected from at least one of Mg, Al, K, Ca, Ti, Fe, Co, Cu, Zn, rare earth metal; The structure of the thiourea is shown in the following formula: ； Wherein, R14, R15 are independently selected from at least one of H, C1-C16 alkyl, phenyl, trifluoromethyl-substituted phenyl, benzyl, C3-C16 heterocyclic group, C5-C16 heteroaryl group. The heteroatoms in the heterocyclyl and heteroaryl groups are selected from at least one of B, N, O, Si, P, and S.

4. The process for the catalytic synthesis of cyclic carbonates according to claim 1 or 3, characterized by the fact that: The molar ratio of the ionic compound, the Lewis acid and the epoxide compound is (0.001-1):(0-1):

10.

5. The process for the catalytic synthesis of cyclic carbonates according to claim 4, characterized by the fact that: The molar ratio of the ionic compound, the Lewis acid and the epoxide compound is (0.001-0.1):(0.001-0.05):

10.

6. The process for the catalytic synthesis of cyclic carbonates according to claim 1 or 3, characterized by the fact that: The reaction temperature of the catalytic cycloaddition reaction is 40-160 ℃; the reaction time of the catalytic cycloaddition reaction is 0.2-30 h.

7. The process for the catalytic synthesis of cyclic carbonates according to claim 6, characterized by the fact that: The reaction pressure of the catalytic cycloaddition reaction is 0.1-5 MPa.

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