A pyridine amine based bifunctional polyionic liquid catalyst, a preparation method and application thereof

Abstract

The application discloses a pyridine amine based bifunctional polyionic liquid catalyst and a preparation method and application thereof. The pyridine amine based bifunctional polyionic liquid catalyst is prepared by using 1-(3-propylamine hydrobromide)-3-vinylimidazole ionic liquid [PAVIm]Br·HBr and 1-pyridyl-2-vinylimidazole ionic liquid [PDVIM]Br as comonomers, adding a crosslinking agent and an initiator, and copolymerizing to synthesize a polyionic liquid catalyst I. The pyridine amine based bifunctional polyionic liquid catalyst has a developed pore structure and rich ion groups (carbonate ions and bicarbonate ions), exhibits high CO2 adsorption performance, can catalyze one-pot synthesis of a chain carbonate from CO2, an epoxide compound and methanol under a solvent-free and cocatalyst-free condition, and realizes efficient utilization of CO2.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalyst preparation, and particularly relates to a pyridine amine-based bifunctional polyionic liquid catalyst as well as a preparation method and application thereof. BACKGROUND

[0002] The over-consumption of fossil energy causes the content of greenhouse gases such as CO2 and CH4 in the atmosphere to continuously increase, leading to global warming, extreme weather changes, continuous rise of sea level, and continuous deterioration of the human environment. China's "double carbon" strategy advocates a green, environmentally friendly, and low-carbon lifestyle, and accelerates the pace of reducing carbon emissions. Using CO2, a non-toxic, inexpensive, and renewable carbon resource, to convert waste products into valuable chemicals with low energy consumption has important strategic value and application prospects, and is the best choice for the sustainable development of human society. At present, there are more than 20 ways to convert CO2 into high-value chemicals, mainly by breaking the carbon-oxygen double bond in CO2 to form new chemical bonds (C-C, C-N, C-O, and C-H) to form new compounds. The relatively mature conversion technology is to convert CO2 into methanol, formic acid, urea, methane, and dimethyl ether, etc., which can also be used to synthesize various carbonates, carboxylic acids, carbamates, and other important compounds with high added value.

[0003] Dimethyl carbonate (DMC) has a molecular formula of (CH3O)2CO and a slightly ester fragrance, and is a non-toxic, easily biodegradable, and environmentally friendly organic compound. Because DMC contains functional groups such as methyl (-CH3), methoxy (-OCH3), and carboxyl (C=O) in its structure, it can undergo a variety of complex synthetic chemical reactions. DMC has a wide range of uses, can be used as an intermediate for the synthesis of engineering plastics, pesticides, and medicines, can be used as a green solvent, an additive, and a lithium ion battery solvent, etc., and can also be added to gasoline to improve the octane rating of the gasoline, enhance the shock resistance, significantly reduce PM2.5 and NOx emissions, and achieve the effect of protecting the environment. x

[0004] At present, the synthesis of dimethyl carbonate mainly has the following methods:

[0005] First, CO2 direct synthesis method

[0006]

[0007] The method has the following deficiencies: 1. The DMC synthesis reaction is limited by thermodynamics, and the activation of CO2 is limited by kinetic inertness; 2. The byproduct water in the DMC synthesis reaction causes the reverse hydrolysis of the chain carbonate.

[0008] Second, traditional indirect synthesis method ​

[0009]

[0010] The method has the following disadvantages: 1. Based on the traditional indirect synthesis method including cycloaddition reaction and ester exchange reaction, different active sites are required for different reactions, so different catalysts are required; 2. Based on the traditional indirect synthesis method including cycloaddition reaction and ester exchange reaction, different reaction conditions are required for different reactions, so different devices are required.

[0011] Third, CO2 one-step coupling reaction method

[0012] The method of putting methanol, epoxide and CH3OH into the same reaction device together to complete the coupling reaction together is called CO2 one-step coupling reaction method. The same catalyst can be used for synchronous reaction, but the heterogeneous catalysts currently used cannot meet the multifunctional active sites required for one-pot coupling preparation of DMC.

[0013] Polyionic liquid (PILs) is a heterogeneous material composed of ILs monomer or ILs and crosslinking agent, with repeated arrangement of anion and cation units, which has the functional characteristics of both ionic liquid and polymer material. Due to the thermodynamic stability and kinetic inertness of CO2, the design of basic sites of PILs is of great significance. Through the functionalization design of ILs monomer, the diversification selection of copolymerization unit and the surface modification of PILs skeleton, the functionalized PILs catalyst can effectively overcome the problems of traditional catalysts such as halogenated metal salt, organic amine liquid base and metal oxide in the reaction of CO2 directed synthesis of chain carbonate, such as easy dissolution of active components, difficulty in construction of functional sites and large amount of use of cocatalysts. Among them, the basic functionalized PILs catalyst can activate CO2 and dissociate CH3OH in the CO2 coupling reaction by further construction of basic sites, which has great research value.

[0014] However, the selection of functional groups and the determination of modification methods still need further research in the preparation and application of basic functionalized PILs catalysts. SUMMARY

[0015] The purpose of the present application is to overcome the shortcomings of the prior art and provide a pyridine amine-based bifunctional polyionic liquid catalyst, its preparation method and application. The pyridine amine-based bifunctional polyionic liquid catalyst provided by the present application can overcome the problem that the existing heterogeneous catalyst cannot meet the multifunctional active sites required for one-pot coupling preparation of DMC when used for catalyzing one-pot coupling of CO2, epoxide and methanol to prepare DMC. The present application copolymerizes primary amine-based ionic liquid (ILs), pyridine-based ILs and DVB free radicals, and then introduces carbonate anions or acetate anions through continuous ion exchange to adjust the active sites of polyionic liquid and obtain high-yield products.

[0016] Technical solution: The purpose of the application is achieved by the following technical solutions:

[0017] The application provides a pyridine amine-based bifunctional polyionic liquid catalyst, which is prepared by copolymerization of 1-(3-propylamine hydrobromide)-3-vinylimidazole ionic liquid [PAVIm]Br·HBr and 1-pyridyl-2-vinylimidazole ionic liquid [PDVIm]Br as comonomers, and addition of a crosslinking agent and an initiator.

[0018] The application also provides a preparation method of the pyridine amine-based bifunctional polyionic liquid catalyst, which comprises the following steps:

[0019] (1) Preparation of 1-(3-propylamine hydrobromide)-3-vinylimidazole ionic liquid [PAVIm]Br·HBr: N-vinylimidazole and 3-bromopropylamine hydrobromide are dissolved in acetonitrile, and the reaction is carried out under N2, the solvent is evaporated, and then washing and drying are performed to obtain the [PAVIm]Br·HBr ionic liquid;

[0020] (2) Preparation of 1-pyridyl-2-vinylimidazole [PDVIm]Br ionic liquid: N-vinylimidazole and 2-bromopyridine are dissolved in ethanol, and the reaction is carried out under N2, the solvent is evaporated, and then washing and drying are performed to obtain the [PDVIm]Br ionic liquid;

[0021] (3) Preparation of the pyridine amine-based polyionic liquid P-D-ILsBr·HBr catalyst: [PAVIm]Br·HBr ionic liquid, [PDVIm]Br ionic liquid, crosslinking agent divinylbenzene DVB and initiator azobisisobutyronitrile AIBN are added into a mixed solvent of water / ethanol, and the reaction is carried out under N2, and then filtering, washing and drying are performed to obtain the P-D-ILsBr·HBr catalyst, i.e., the polyionic liquid catalyst I.

[0022] Preferably, in step (1), the molar ratio of N-vinylimidazole to 3-bromopropylamine hydrobromide is 1:1-2.5, the molar concentration of N-vinylimidazole in acetonitrile is 1-2 mmol / ml, the reaction temperature is 70-90°C, and the reaction time is 18-24 h; the washing is performed by using ethyl acetate, and the drying is performed by using vacuum drying, and the drying temperature is 55-75°C, and the drying time is 18-24 h.

[0023] Preferably, in step (2), the molar ratio of N-vinylimidazole to 2-bromopyridine is 1:1-2, the molar concentration of N-vinylimidazole in ethanol is 1-2 mmol / ml, the reaction temperature is 70-90°C, and the reaction time is 18-24 h; the washing is performed by using ethyl acetate, and the drying is performed by using vacuum drying, and the drying temperature is 55-75°C, and the drying time is 18-24 h.

[0024] Preferably, in step (3), the molar ratio of the [PAVIm]Br·HBr ionic liquid, [PDVIm]Br and crosslinking agent DVB is 1:0.5-2:0.5-2; the amount of initiator AIBN is 2.3-5.6wt% of the total mass of [PAVIm]Br·HBr, [PDVIm]Br and crosslinking agent DVB; the molar concentration of [PAVIm]Br·HBr ionic liquid in the mixed solvent is 0.1-0.2mmol / ml; the volume ratio of water and ethanol is 1:4-9; the reaction temperature is 75-95℃, and the reaction time is 18-24h; the washing uses ethanol washing; the drying uses vacuum drying, the drying temperature is 55-75℃, and the drying time is 18-24h.

[0025] The application also provides a pyridine amine-based bifunctional polyionic liquid catalyst, which is obtained by anion exchange reaction of the above-mentioned polyionic liquid catalyst I with a sodium carbonate aqueous solution to obtain polyionic liquid catalyst II, and by anion exchange reaction of the above-mentioned polyionic liquid catalyst I with a sodium acetate aqueous solution to obtain polyionic liquid catalyst III.

[0026] The application also provides a preparation method of the polyionic liquid catalyst II and the polyionic liquid catalyst III, wherein the concentration of the sodium carbonate aqueous solution or the sodium acetate aqueous solution is 0.7-1.7mol / L; the anion exchange reaction is carried out at room temperature under stirring, and after the reaction is completed, the product is filtered, washed with hot water and vacuum dried to obtain the polyionic liquid catalyst; the stirring time is 48-72h; the drying temperature is 55-75℃, and the drying time is 18-24h.

[0027] A specific preferred embodiment of the application is a preparation method of the pyridine amine-based bifunctional polyionic liquid catalyst, which comprises the following steps:

[0028] (1) dispersing N-vinylimidazole in acetonitrile, adding 3-bromopropylamine hydrobromide and mixing uniformly, reacting at 70-90℃ for 18-24h under N2 protection, removing the solvent by rotary evaporation, washing with ethyl acetate, and vacuum drying at 55-75℃ for 18-24h to obtain 1-(3-propylamine hydrobromide)-3-vinylimidazole ionic liquid ([PAVIm]Br·HBr);

[0029] (2) dispersing N-vinylimidazole in ethanol, adding 2-bromopyridine and mixing uniformly, reacting at 70-90℃ for 18-24h under N2 protection, removing the solvent by rotary evaporation, washing with ethyl acetate, and vacuum drying at 55-75℃ for 18-24h to obtain 1-pyridyl-2-vinylimidazole ionic liquid ([PDVIm]Br);

[0030] (3) The ion liquid, DVB and AIBN obtained above are added into a mixed solvent of water / ethanol, stirred at room temperature for 2h, and then reacted at 75-95°C for 18-24h under N2 protection, filtered, washed with ethanol, and dried at 55-75°C under vacuum for 18-24h to obtain a catalyst P-D-ILsBr·HBr;

[0031] (4) The catalyst P-D-ILsBr·HBr obtained above is dispersed in a sodium carbonate aqueous solution or a sodium acetate aqueous solution, stirred at room temperature for 48-72h to perform anion exchange, the solid is filtered, washed with hot water, and dried at 55-75°C under vacuum for 18-24h to obtain P-D-ILsCO3 and P-D-ILsAC catalysts.

[0032] The application further provides application of the pyridine amine-based bifunctional polyionic liquid catalyst in one-pot coupling preparation of DMC from CO2, epoxide and methanol.

[0033] In a preferred embodiment of the application, the polyionic liquid catalyst, raw material epoxide and methanol are added into a reaction kettle, CO2 is used to replace the air in the kettle, and then the reaction is started after the kettle is pressurized and heated to a reaction temperature. After the reaction is completed, the catalyst and the reaction product are separated by centrifugation.

[0034] Further preferably, the raw material epoxide is any one of epichlorohydrin, styrene oxide or epoxypropanol; the mass ratio of the raw material epoxide to the polyionic liquid catalyst is 1:0.036-0.09; the CO2 pressure is 5-12.5 bar; the molar ratio of methanol to epoxide is 10-25:1; and the reaction temperature is 100-160°C and the reaction time is 1-4h.

[0035] Advantages:

[0036] (1) The pyridine amine-based bifunctional polyionic liquid material prepared in the application has abundant basic sites and developed pore structures, and can be used as a good catalyst for one-pot coupling preparation of chain carbonates from CO2, epoxide and methanol under the conditions of no solvent and no cocatalyst, and has a good synergistic effect on the coupling reaction.

[0037] (2) The pyridine amine-based bifunctional polyionic liquid catalyst is prepared by radical copolymerization of primary amine-based ILs, pyridine-based ILs and DVB and continuous anion exchange. With the material synthesis characteristics of PILs, the basic bifunctional PILs catalyst can be constructed.

[0038] (3) The application adopts a new method of coupling CO2 cycloaddition and CH3OH ester exchange reaction in the same reactor to generate DMC, which can not only retain the high yield of the indirect synthesis of CO2, but also omit the separation operation of the intermediate product cyclic carbonate, thereby reducing energy consumption, investment and production cost. The material structure prepared by the application is adjustable, stable in property and has good adsorption and catalytic repeated stability, simultaneously promotes the green conversion of low-value C1 resources to high-value chemicals, meets the demand of the national 'double carbon' strategy and has good application prospect. DETAILED DESCRIPTION

[0039] The technical solutions of the application will be described in detail below through specific examples, but the protection scope of the application is not limited to the examples.

[0040] If the specific technology or condition is not specified in the examples, the technology or condition is carried out according to the technology or condition described in the literature in the field or according to the product instruction. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be purchased through a regular channel.

[0041] The experimental methods in the following examples are conventional methods, unless otherwise specified. The test materials used in the following examples are commercially available products, unless otherwise specified.

[0042] Example 1

[0043] Step 1: 10 mmol of N-vinylimidazole was dispersed in 10 ml of acetonitrile, 10 mmol of 3-bromopropylamine hydrobromide was added and mixed uniformly, under N2 protection, 70℃ reaction was carried out for 18 h, the solvent was removed by rotary evaporation, washed with ethyl acetate, and vacuum dried at 55℃ for 18 h to obtain 1-(3-propylamine hydrobromide)-3-vinylimidazole ionic liquid ([PAVIm]Br·HBr).

[0044] Step 2: 10 mmol of N-vinylimidazole was dispersed in 10 ml of ethanol, 10 mmol of 2-bromopyridine was added and mixed uniformly, under N2 protection, 70℃ reaction was carried out for 18 h, the solvent was removed by rotary evaporation, washed with ethyl acetate, and vacuum dried at 55℃ for 18 h to obtain 1-pyridyl-2-vinylimidazole ionic liquid ([PDVIm]Br).

[0045] Step 3: 10 mmol of [PAVIm]Br·HBr ionic liquid, 5 mmol of [PDVIm]Br ionic liquid and 5 mmol of DVB were added to a mixed solvent composed of 10 ml of water and 90 ml of ethanol, then 116 mg of AIBN was added, stirred at room temperature for 2 h, reacted at 75℃ for 18 h under N2 protection, filtered, washed with ethanol (3×20 ml), and vacuum dried at 55℃ for 18 h to obtain the catalyst P-D-ILsBr·HBr.

[0046] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 0.7 mol / L aqueous sodium carbonate solution and stirred at room temperature for 48 h, filtered, washed with hot water (3 x 20 mL), and dried at 55 °C under vacuum for 18 h to give P-D-ILsCO3catalyst.

[0047] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 0.7 mol / L aqueous sodium acetate solution and stirred at room temperature for 48 h, filtered, washed with hot water (3 x 20 mL), and dried at 55 °C under vacuum for 18 h to give P-D-ILsACcatalyst.

[0048] Example 2

[0049] Step 1: 10 mmol of N-vinylimidazole was dispersed in 5 ml of acetonitrile, 25 mmol of 3-bromopropylamine hydrobromide was added and mixed uniformly, and then the mixture was reacted at 90 °C for 24 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 75 °C under vacuum for 24 h to give 1-(3- propylammonium hydrobromide)-3-vinylimidazole ionic liquid ([PAVIm]Br-HBr).

[0050] Step 2: 10 mmol of N-vinylimidazole was dispersed in 5 ml of ethanol, 20 mmol of 2-bromopyridine was added and mixed uniformly, and then the mixture was reacted at 90 °C for 24 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 75 °C under vacuum for 24 h to give 1-pyridyl-2-vinylimidazole ionic liquid ([PDVIm]Br).

[0051] Step 3: 10 mmol of [PAVIm]Br-HBr ionic liquid, 20 mmol of [PDVIm]Br ionic liquid, and 20 mmol of DVB were added to a mixed solvent consisting of 10 ml of water and 40 ml of ethanol, followed by the addition of 560 mg of AIBN. The mixture was stirred at room temperature for 2 h, and then reacted at 95 °C for 24 h under N2protection. The mixture was filtered, washed with ethanol (3 x 20 mL), and dried at 75 °C under vacuum for 24 h to give the catalyst P-D-ILsBr-HBr.

[0052] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.7 mol / L aqueous sodium carbonate solution and stirred at room temperature for 72 h, filtered, washed with hot water (3 x 20 mL), and dried at 75 °C under vacuum for 24 h to give P-D-ILsCO3catalyst.

[0053] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.7 mol / L aqueous sodium acetate solution and stirred at room temperature for 72 h, filtered, washed with hot water (3 x 20 mL), and dried at 75 °C under vacuum for 24 h to give P-D-ILsAC catalyst.

[0054] Example 3

[0055] Step 1: 10 mmol of N-vinylimidazole was dispersed in 6 mL of acetonitrile, 15 mmol of 3-bromopropylamine hydrobromide was added and mixed well, and the mixture was reacted at 80 °C for 24 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 60 °C under vacuum for 22 h to give 1-(3- propylammonium hydrobromide)-3-vinylimidazole ionic liquid ([PAVIm]Br-HBr).

[0056] Step 2: 10 mmol of N-vinylimidazole was dispersed in 8 mL of ethanol, 15 mmol of 2-bromopyridine was added and mixed well, and the mixture was reacted at 80 °C for 24 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 60 °C under vacuum for 22 h to give 1-pyridyl-2-vinylimidazole ionic liquid ([PDVIm]Br).

[0057] Step 3: 10 mmol of [PAVIm]Br-HBr ionic liquid, 5 mmol of [PDVIm]Br ionic liquid, and 10 mmol of DVB were added to a mixed solvent consisting of 10 mL of water and 50 mL of ethanol, followed by the addition of 170 mg of AIBN. The mixture was stirred at room temperature for 2 h, and then reacted at 85 °C for 24 h under N2protection. The mixture was filtered, washed with ethanol (3 x 20 mL), and dried at 55 °C under vacuum for 24 h to give the catalyst P-D-ILsBr-HBr.

[0058] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 0.7 mol / L aqueous sodium carbonate solution and stirred at room temperature for 48 h, filtered, washed with hot water (3 x 20 mL), and dried at 55 °C under vacuum for 24 h to give P-D-ILsCO3catalyst.

[0059] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 0.7 mol / L aqueous sodium acetate solution and stirred at room temperature for 48 h, filtered, washed with hot water (3 x 20 mL), and dried at 55 °C under vacuum for 24 h to give P-D-ILsAC catalyst.

[0060] Example 4

[0061] Step 1 : 10 mmol N-vinylimidazole was dispersed in 5 ml acetonitrile, 10 mmol 3-bromopropylamine hydrobromide was added and mixed well, under N2 protection, 75 °C for 24 h, the solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 60 °C under vacuum for 24 h to obtain 1-(3- propylammonium hydrobromide)-3-vinylimidazole bromide ionic liquid ([PAVIm]Br-HBr).

[0062] Step 2: 10 mmol N-vinylimidazole was dispersed in 5 ml ethanol, 10 mmol 2- bromopyridine was added and mixed well, under N2 protection, 75 °C for 24 h, the solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 60 °C under vacuum for 24 h to obtain 1-pyridyl-2-vinylimidazole bromide ionic liquid ([PDVIm]Br).

[0063] Step 3: 10 mmol [PAVIm]Br-HBr ionic liquid, 5 mmol [PDVIm]Br ionic liquid and 10 mmol DVB were added to a mixed solvent consisting of 10 ml water and 60 ml ethanol, followed by the addition of 233 mg AIBN, stirring at room temperature for 2 h, under N2 protection, 85 °C for 24 h, filtration, ethanol (3 x 20 mL) washing, and drying at 55 °C under vacuum for 24 h to obtain the catalyst P-D-ILsBr-HBr.

[0064] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 0.7 mol / L aqueous sodium carbonate solution, stirred at room temperature for 48 h, filtered, washed with hot water (3 x 20 mL), and dried at 55 °C under vacuum for 24 h to obtain the P-D-ILsCO3 catalyst.

[0065] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 0.7 mol / L aqueous sodium acetate solution, stirred at room temperature for 48 h, filtered, washed with hot water (3 x 20 mL), and dried at 55 °C under vacuum for 24 h to obtain the P-D-ILsAC catalyst.

[0066] Example 5

[0067] Step 1 : 10 mmol N-vinylimidazole was dispersed in 5 ml acetonitrile, 20 mmol 3-bromopropylamine hydrobromide was added and mixed well, under N2 protection, 90 °C for 18 h, the solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 70 °C under vacuum for 20 h to obtain 1-(3- propylammonium hydrobromide)-3-vinylimidazole bromide ionic liquid ([PAVIm]Br-HBr).

[0068] Step 2: 10 mmol of N-vinylimidazole was dispersed in 5 ml of ethanol, 16 mmol of 2-bromopyridine was added and mixed well, and the mixture was reacted at 90°C for 18 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 70°C under vacuum for 20 h to obtain 1-pyridyl-2-vinylimidazole bromide ionic liquid ([PDVIm]Br).

[0069] Step 3: 10 mmol of [PAVIm]Br·HBr ionic liquid, 10 mmol of [PDVIm]Br ionic liquid, and 10 mmol of DVB were added to a mixed solvent consisting of 10 ml of water and 70 ml of ethanol, followed by the addition of 260 mg of AIBN. The mixture was stirred at room temperature for 2 h, and then reacted at 85°C for 20 h under N2protection. The mixture was filtered, washed with ethanol (3 x 20 ml), and dried at 55°C under vacuum for 24 h to obtain the catalyst P-D-ILsBr·HBr.

[0070] Step 4: The P-D-ILsBr·HBr catalyst prepared in the above step was dispersed in a 1.4 mol / L aqueous sodium carbonate solution and stirred at room temperature for 48 h. The mixture was filtered, washed with hot water (3 x 20 ml), and dried at 60°C under vacuum for 22 h to obtain the P-D-ILsCO3 catalyst.

[0071] Step 5: The P-D-ILsBr·HBr catalyst prepared in the above step was dispersed in a 1.4 mol / L aqueous sodium acetate solution and stirred at room temperature for 72 h. The mixture was filtered, washed with hot water (3 x 20 ml), and dried at 70°C under vacuum for 24 h to obtain the P-D-ILsAC catalyst.

[0072] Example 6

[0073] Step 1: 10 mmol of N-vinylimidazole was dispersed in 8 ml of acetonitrile, 23 mmol of 3-bromopropylamine hydrobromide was added and mixed well, and the mixture was reacted at 75°C for 18 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 75°C under vacuum for 18 h to obtain 1-(3- propylamine hydrobromide)-3-vinylimidazole bromide ionic liquid ([PAVIm]Br·HBr).

[0074] Step 2: 10 mmol of N-vinylimidazole was dispersed in 7 ml of ethanol, 15 mmol of 2-bromopyridine was added and mixed well, and the mixture was reacted at 80°C for 24 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 65°C under vacuum for 22 h to obtain 1-pyridyl-2-vinylimidazole bromide ionic liquid ([PDVIm]Br).

[0075] Step 3: 10 mmol of [PAVIm]Br-HBr ionic liquid, 17 mmol of [PDVIm]Br ionic liquid and 16 mmol of DVB were added into a mixed solvent consisting of 10 ml of water and 70 ml of ethanol, followed by the addition of 432 mg of AIBN, stirring at room temperature for 2 h, reaction at 75 °C for 22 h under N2protection, filtration, washing with ethanol (3 x 20 ml), and vacuum drying at 70 °C for 24 h to obtain the catalyst P-D-ILsBr-HBr.

[0076] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.6 mol / L aqueous sodium carbonate solution, stirring at room temperature for 70 h, filtration, washing with hot water (3 x 20 ml), and vacuum drying at 55 °C for 24 h to obtain the P-D-ILsCO3catalyst.

[0077] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.6 mol / L aqueous sodium acetate solution, stirring at room temperature for 70 h, filtration, washing with hot water (3 x 20 ml), and vacuum drying at 55 °C for 24 h to obtain the P-D-ILsACcatalyst.

[0078] Example 7

[0079] Step 1: 10 mmol of N-vinylimidazole was dispersed in 10 ml of acetonitrile, 20 mmol of 3-bromopropylamine hydrobromide was added and mixed uniformly, reaction at 85 °C for 20 h under N2protection, the solvent was removed by rotary evaporation, washed with ethyl acetate, and vacuum dried at 60 °C for 24 h to obtain 1-(3- propylammonium hydrobromide)-3-vinylimidazole ionic liquid ([PAVIm]Br-HBr).

[0080] Step 2: 10 mmol of N-vinylimidazole was dispersed in 10 ml of ethanol, 20 mmol of 2-bromopyridine was added and mixed uniformly, reaction at 85 °C for 20 h under N2protection, the solvent was removed by rotary evaporation, washed with ethyl acetate, and vacuum dried at 60 °C for 22 h to obtain 1-pyridyl-2-vinylimidazole ionic liquid ([PDVIm]Br).

[0081] Step 3: 10 mmol of [PAVIm]Br-HBr ionic liquid, 15 mmol of [PDVIm]Br ionic liquid and 15 mmol of DVB were added into a mixed solvent consisting of 10 ml of water and 78 ml of ethanol, followed by the addition of 500 mg of AIBN, stirring at room temperature for 2 h, reaction at 85 °C for 20 h under N2protection, filtration, washing with ethanol (3 x 20 ml), and vacuum drying at 60 °C for 24 h to obtain the catalyst P-D-ILsBr-HBr.

[0082] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.0 mol / L aqueous sodium carbonate solution and stirred at room temperature for 65 h, filtered, washed with hot water (3 x 20 mL), and dried at 75 °C under vacuum for 24 h to give P-D-ILsCO3catalyst.

[0083] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.0 mol / L aqueous sodium acetate solution and stirred at room temperature for 70 h, filtered, washed with hot water (3 x 20 mL), and dried at 70 °C under vacuum for 22 h to give P-D-ILsACcatalyst.

[0084] Example 8

[0085] Step 1: 10 mmol of N-vinylimidazole was dispersed in 6 mL of acetonitrile, 20 mmol of 3-bromopropylamine hydrobromide was added and mixed well, and the mixture was reacted at 80 °C for 20 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 55 °C under vacuum for 24 h to give 1-(3- propylammonium hydrobromide)-3-vinylimidazole ionic liquid ([PAVIm]Br-HBr).

[0086] Step 2: 10 mmol of N-vinylimidazole was dispersed in 8 mL of ethanol, 18 mmol of 2-bromopyridine was added and mixed well, and the mixture was reacted at 90 °C for 18 h under N2protection. The solvent was removed by rotary evaporation, washed with ethyl acetate, and dried at 60 °C under vacuum for 20 h to give 1-pyridyl-2-vinylimidazole ionic liquid ([PDVIm]Br).

[0087] Step 3: 10 mmol of [PAVIm]Br-HBr ionic liquid, 15 mmol of [PDVIm]Br ionic liquid, and 20 mmol of DVB were added to a mixed solvent consisting of 10 mL of water and 80 mL of ethanol, followed by the addition of 489 mg of AIBN. The mixture was stirred at room temperature for 2 h, reacted at 80 °C for 20 h under N2protection, filtered, washed with ethanol (3 x 20 mL), and dried at 70 °C under vacuum for 22 h to give the catalyst P-D-ILsBr-HBr.

[0088] Step 4: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.6 mol / L aqueous sodium carbonate solution and stirred at room temperature for 58 h, filtered, washed with hot water (3 x 20 mL), and dried at 70 °C under vacuum for 23 h to give P-D-ILsCO3catalyst.

[0089] Step 5: The P-D-ILsBr-HBr catalyst prepared above was dispersed in 1.6 mol / L aqueous sodium acetate solution and stirred at room temperature for 56 h, filtered, washed with hot water (3 x 20 mL), and dried at 75 °C under vacuum for 20 h to give P-D-ILsACcatalyst.

[0090] The P-DILsBr-HBr, P-DILsCO3 and P-DILsAC catalysts prepared in the above examples were used to catalyze the one-pot coupling reaction of CO2, epoxide and methanol to prepare DMC, as follows:

[0091] Application Example 1

[0092] 1.10 g (15 mmol) of epichlorohydrin, 0.06 g of P-DILsBr-HBr and 5.2 g (165 mmol) of methanol were weighed in sequence into a 50 mL high-pressure microreactor, CO2 was used to replace the air in the reactor, and then the pressure was increased to 12.5 bar. After the temperature was increased to 100°C, the reaction was started. The reaction time was 1.5 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained in the reaction was analyzed by gas chromatography. The conversion rate of epichlorohydrin was 98.4%, and the yield of DMC was 50.4%.

[0093] Application Example 2

[0094] 1.10 g (12 mmol) of epichlorohydrin, 0.06 g of P-DILsCO3 and 5.3 g (166 mmol) of methanol were weighed in sequence into a 50 mL high-pressure microreactor, CO2 was used to replace the air in the reactor, and then the pressure was increased to 10 bar. After the temperature was increased to 120°C, the reaction was started. The reaction time was 2 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained in the reaction was analyzed by gas chromatography. The conversion rate of epichlorohydrin was 99.1%, and the yield of DMC was 53.1%.

[0095] Application Example 3

[0096] 1.10 g (9 mmol) of styrene oxide, 0.05 g of P-DILsAC and 4.7 g (148 mmol) of methanol were weighed in sequence into a 50 mL high-pressure microreactor, CO2 was used to replace the air in the reactor, and then the pressure was increased to 12.5 bar. After the temperature was increased to 120°C, the reaction was started. The reaction time was 1 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained in the reaction was analyzed by gas chromatography. The conversion rate of epichlorohydrin was 98.8%, and the yield of DMC was 52.4%.

[0097] Application Example 4

[0098] P-DILsBr-HBr, 0.04 g, and 7.5 g (233 mmol) of methanol were weighed into a 50 mL high-pressure microreactor in sequence, the reactor was purged with CO2to replace the air in the reactor, and then pressurized to 10 bar. After the reactor was heated to 140°C, the reaction was started. The reaction time was 1 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained from the reaction was analyzed by gas chromatography. The conversion of epichlorohydrin was 97.9%, and the yield of DMC was 51.4%.

[0099] Application Example 5

[0100] P-DILsAC, 0.04 g, and 8.4 g (264 mmol) of methanol were weighed into a 50 mL high-pressure microreactor in sequence, the reactor was purged with CO2to replace the air in the reactor, and then pressurized to 10 bar. After the reactor was heated to 160°C, the reaction was started. The reaction time was 1 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained from the reaction was analyzed by gas chromatography. The conversion of epichlorohydrin was 99.2%, and the yield of DMC was 54.6%.

[0101] Application Example 6

[0102] P-DILsBr-HBr, 0.05 g, and 6.4 g (200 mmol) of methanol were weighed into a 50 mL high-pressure microreactor in sequence, the reactor was purged with CO2to replace the air in the reactor, and then pressurized to 10 bar. After the reactor was heated to 120°C, the reaction was started. The reaction time was 1 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained from the reaction was analyzed by gas chromatography. The conversion of epichlorohydrin was 95.1%, and the yield of DMC was 51.4%.

[0103] Application Example 7

[0104] P-DILsCO3, 0.05 g, and 6.4 g (200 mmol) of methanol were weighed into a 50 mL high-pressure microreactor in sequence, the reactor was purged with CO2to replace the air in the reactor, and then pressurized to 10 bar. After the reactor was heated to 120°C, the reaction was started. The reaction time was 1 h. After the reaction was completed, the catalyst and the reaction product were separated by centrifugation. The liquid obtained from the reaction was analyzed by gas chromatography. The conversion of epichlorohydrin was 98.7%, and the yield of DMC was 54.1%.

[0105] Application Example 8

[0106] Take 1.10 g (15 mmol) of propylene oxide, 0.04 g of P-DILsBr-HBr and 4.8 g (150 mmol) of methanol in turn into a 50 mL high-pressure micro-reactor, replace the air in the reactor with CO2, then pressurize to 5 bar, heat to 100°C to start the reaction, the reaction time is 1 h, after the reaction is completed, the catalyst and reaction product are separated by centrifugation. Gas chromatography analysis of the liquid obtained by reaction shows that the conversion rate of propylene oxide is 96.2% and the yield of DMC is 49.8%.

[0107] Application Example 9

[0108] Take 1.10 g (15 mmol) of propylene oxide, 0.1 g of P-DILsBr-HBr and 7.2 g (225 mmol) of methanol in turn into a 50 mL high-pressure micro-reactor, replace the air in the reactor with CO2, then pressurize to 12.5 bar, heat to 140°C to start the reaction, the reaction time is 4 h, after the reaction is completed, the catalyst and reaction product are separated by centrifugation. Gas chromatography analysis of the liquid obtained by reaction shows that the conversion rate of propylene oxide is 99.1 and the yield of DMC is 54.2%.

[0109] The application example experiment results are shown in Table 1.

[0110] Table 1 Application Example Experiment Results

[0111]

[0112]

[0113] As described above, although the present application has been shown and described with reference to specific preferred embodiments, it is to be understood that various modifications and changes can be made to it without departing from the spirit and scope of the application as defined in the appended claims.

Claims

1. A pyridineamine-based bifunctional polyionic liquid catalyst, characterized in that, Polyionic liquid catalyst I was synthesized by copolymerizing 1-(3-propylamine hydrobromide)-3-vinylimidazolium bromide ionic liquid [PAVIm]Br·HBr and 1-pyridyl-2-vinylimidazolium bromide ionic liquid [PDVIM]Br as comonomers, adding divinylbenzene DVB as a crosslinking agent and an initiator.

2. The method for preparing the pyridineamine-based bifunctional polyionic liquid catalyst according to claim 1, characterized in that, Includes the following steps: (1) Preparation of 1-(3-propylamine hydrobromide)-3-vinylimidazolium ionic liquid [PAVIm]Br·HBr: N-vinylimidazolium and 3-bromopropylamine hydrobromide were dissolved in acetonitrile and reacted under N2. The solvent was evaporated, washed, and dried to obtain [PAVIm]Br·HBr ionic liquid. (2) Preparation of 1-pyridyl-2-vinylimidazolium bromide [PDVIM]Br ionic liquid: N-vinylimidazolium and 2-bromopyridine were dissolved in ethanol, reacted under N2, the solvent was evaporated, washed, and dried to obtain [PDVIm]Br ionic liquid; (3) Preparation of pyridine-amine polyionic liquid PD-ILsBr·HBr catalyst: [PAVIm]Br·HBr ionic liquid, [PDVIm]Br ionic liquid, crosslinking agent DVB and initiator AIBN are added to a water / ethanol mixed solvent, reacted under N2, filtered, washed and dried to obtain PD-ILsBr·HBr catalyst, i.e. polyionic liquid catalyst I.

3. The preparation method according to claim 2, characterized in that, In step (1), the molar ratio of N-vinylimidazole to 3-bromopropylamine hydrobromide is 1:1~2.5, and the molar concentration of N-vinylimidazole in acetonitrile is 1~2 mmol / ml; the reaction temperature is 70~90℃, and the reaction time is 18~24h; the washing is performed with ethyl acetate; the drying is performed under vacuum at a temperature of 55~75℃ for 18~24h.

4. The preparation method according to claim 2, characterized in that, In step (2), the molar ratio of N-vinylimidazole to 2-bromopyridine is 1:1~2, and the molar concentration of N-vinylimidazole in ethanol is 1~2 mmol / ml; the reaction temperature is 70~90℃, and the reaction time is 18~24 h; the washing is performed with ethyl acetate; the drying is performed under vacuum at a temperature of 55~75℃ for 18~24 h.

5. The preparation method according to claim 2, characterized in that, In step (3), the molar ratio of the [PAVIm]Br·HBr ionic liquid, [PDVIm]Br, and crosslinking agent DVB is 1:0.5~2:0.5~2; the amount of initiator AIBN is 2.3~5.6wt% of the sum of the masses of [PAVIm]Br·HBr, [PDVIm]Br, and crosslinking agent DVB; the molar concentration of [PAVIm]Br·HBr ionic liquid in the mixed solvent is 0.1~0.2mmol / ml; the volume ratio of water to ethanol is 1:4~9; the reaction temperature is 75~95℃, and the reaction time is 18~24 h; the washing is done with ethanol; the drying is done by vacuum drying at a temperature of 55~75℃ for 18~24 h.

6. A pyridineamine-based bifunctional polyionic liquid catalyst, characterized in that, Polyionic liquid catalyst I according to claim 1 is subjected to an anion exchange reaction with sodium carbonate aqueous solution to obtain polyionic liquid catalyst II; polyionic liquid catalyst I according to claim 1 is subjected to an anion exchange reaction with sodium acetate aqueous solution to obtain polyionic liquid catalyst III.

7. The method for preparing the pyridineamine-based bifunctional polyionic liquid catalyst according to claim 6, characterized in that, The concentration of the sodium carbonate aqueous solution or sodium acetate aqueous solution is 0.7~1.7 mol / L; the anion exchange reaction is carried out by stirring at room temperature, and after the reaction is completed, the mixture is filtered, washed with hot water, and vacuum dried to obtain the polyionic liquid catalyst; the stirring time is 48~72 h; the drying temperature is 55~75℃, and the drying time is 18~24 h.

8. The application of the pyridine-amine bifunctional polyionic liquid catalyst according to any one of claims 1 or 6 in the one-pot coupled preparation of DMC from CO2, epoxide and methanol.

9. The application according to claim 8, characterized in that, The polyionic liquid catalyst, raw material epoxide, and methanol as described in claim 1 or 6 are added to the reactor. After the air in the reactor is replaced with CO2, the reactor is pressurized and heated to the reaction temperature to start the reaction. After the reaction is completed, the catalyst and reaction products are separated by centrifugation.

10. The application according to claim 9, characterized in that, The raw material epoxide is any one of epichlorohydrin, styrene oxide, or epichlorohydrin; the mass ratio of the raw material epoxide to the polyionic liquid catalyst is 1:0.036~0.09; the CO2 pressure is 5~12.5 bar; the molar ratio of methanol to epoxide is 10~25:1; the reaction temperature is 100~160℃, and the reaction time is 1~4 h.

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