Amine-functionalized mesoporous polymeric ionic liquid as well as preparation method and application thereof

Abstract

The invention provides an amine-functionalized mesoporous polymeric ionic liquid and a preparation method and application thereof.The amine-functionalized mesoporous polymeric ionic liquid is prepared through the steps that nano-silica serves as a hard mask plate, 1, 3, 5-tri (bromomethyl) benzene serves as a monomer, a polymer precursor is synthesized through a Friedel-Crafts alkylation reaction, then a hollow polymer precursor is obtained through HF acid etching, and the hollow polymer precursor is subjected to heat treatment to obtain the amine-functionalized mesoporous polymeric ionic liquid. And finally, modifying and synthesizing by tetramethyl propane diamine. The prepared amine functionalized mesoporous polymeric ionic liquid has uniform pores, is used for catalyzing the cycloaddition reaction of an epoxy compound and carbon dioxide, and can efficiently synthesize cyclic carbonate under the conditions of normal pressure, no solvent and no cocatalyst. The synthesis raw materials of the catalyst are cheap and easy to prepare and recover, and the catalyst has good recyclability.

Description

Technical Field

[0001] The invention relates to the technical field of synthesis of cyclic carbonates, and in particular to an amine-functionalized mesoporous polymerized ionic liquid and a preparation method and application thereof. Background Art

[0002] The greenhouse effect has become one of the concerns of environmental issues. 2 The concentration of gases is the main factor causing the greenhouse effect. Researchers are paying more and more attention to the CO 2 In addition, CO 2 It is also an abundant and inexpensive C1 resource, so many researchers focus on CO 2 The capture, storage and utilization of CO2 can transform it into high value-added products. 2 The reaction with epoxides to form cyclic carbonates is the current CO 2 It is one of the most effective ways to utilize resources. It has atom economy and its products are intermediates for medicines / pesticides / organic synthesis. It has important uses in the fields of batteries, fine chemicals, medicines and materials.

[0003] Given that CO 2 The inherent thermodynamic stability of CO 2 Cycloaddition reactions generally require a catalyst to be realized. 2 A catalytic system for converting epoxides into cyclic carbonates, wherein CN102775378A discloses a method for the solvent-free catalytic synthesis of cyclic carbonates, characterized in that the method does not require an organic solvent, the catalyst provided by the invention has high activity, good selectivity, mild reaction conditions, and the catalyst is cheap and easy to prepare, but requires coordination with a metal complex. The introduction of a metal complex not only causes secondary pollution to the environment, but also increases the synthesis cost. CN109382128A discloses a method for catalyzing CO 2 A catalyst for synthesizing cyclic carbonates, characterized in that the catalyst can convert CO into 2 Epoxides are converted into cyclic carbonates. However, this catalytic system requires the addition of a co-catalyst, TBAB, which increases costs and makes recovery difficult, causing secondary environmental pollution. Other reports also show that the catalyst cannot fully expose its internal active sites due to the limited pore size, and the pores are in the CO 2 The cycloaddition reaction is easily blocked by the product cyclic carbonate, resulting in reduced catalytic activity. Summary of the invention

[0004] The purpose of the present invention is to provide an amine functionalized mesoporous polymeric ionic liquid and its preparation method and application in view of the problem that the pore structure of porous polymeric ionic liquid materials in the prior art is difficult to control. 2 For the hard film, 1,3,5-tri(bromomethyl)benzene (TBB) was used as a monomer to synthesize a polymer precursor through Friedel-Crafts alkylation reaction, and then a hollow polymer precursor was obtained by HF acid etching, and finally tetramethylpropylenediamine (TMPDA) was used to modify the synthesized amine-functionalized mesoporous polymeric ionic liquid with uniform pores. The prepared polymeric ionic liquid material was used to catalyze the reaction of epoxy compounds and CO 2 The corresponding cyclic carbonate can be obtained in high yield and high selectivity by the cycloaddition reaction under normal pressure, solvent-free and catalyst-free conditions. The raw materials for the synthesis of the catalyst are cheap and easy to obtain, the operation method is simple, the catalyst has high active sites, the dosage is small, and it is easy to recover and recycle, and has good performance, and has certain industrial application prospects.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] First, the present invention provides a method for preparing an amine-functionalized mesoporous polymeric ionic liquid, comprising the following steps:

[0007] (1) Nano-SiO 2 and 1,2-dichloroethane were placed in a reaction vessel, ultrasonically dispersed, TBB was added, and ultrasonically dissolved; anhydrous FeCl was added under a nitrogen atmosphere 3 , condense and reflux at 40-80° C. for 1-3 hours, cool to room temperature, filter and dry to obtain a first polymer precursor;

[0008] (2) mixing the first polymer precursor with a 10 wt % HF aqueous solution, stirring and dispersing at room temperature, centrifuging, filtering, and drying to obtain a second polymer precursor;

[0009] (3) placing the second polymer precursor, toluene and TMPDA in a reaction container, heating to 80-100° C. and stirring for 24-48 hours, cooling to room temperature, filtering and drying to obtain an amine-functionalized mesoporous polymerized ionic liquid with uniform pores.

[0010] Furthermore, the nano-SiO 2 The average particle size is 100 nm.

[0011] Furthermore, in step (1): 1.0 parts by weight of nano-SiO 2 100 to 150 parts by weight of 1,2-dichloroethane is required for dispersion;

[0012] 1.0 parts by weight of nano-SiO 2 The amount of TBB to be added is 1.5 to 2.0 parts by weight;

[0013] 1.0 parts by weight of nano-SiO 2 Need to add anhydrous FeCl 3 The amount is 0.5 to 1.0 parts by weight.

[0014] Furthermore, in the step (2), 70 to 90 parts by weight of a 10 wt% HF aqueous solution are added to 1 part by weight of the first polymer precursor for mixing.

[0015] Furthermore, in the step (3), the mass ratio of the second polymer precursor, toluene and TMPDA is 15-20:400-450:70-80.

[0016] Secondly, the present invention also provides an amine-functionalized mesoporous polymerized ionic liquid, which is prepared by the above-mentioned preparation method of the amine-functionalized mesoporous polymerized ionic liquid with uniform pores.

[0017] Thirdly, the present invention also provides an application of the above-mentioned amine-functionalized mesoporous polymeric ionic liquid, which is used to catalyze the reaction of carbon dioxide and epoxy compounds to synthesize cyclic carbonates. Specifically, epoxy compounds and CO 2 The cyclic carbonate is synthesized by catalysis at a reaction pressure of 0.1 MPa, a reaction temperature of 80-100° C., an amine-functionalized mesoporous polymerized ionic liquid as a catalyst, and a reaction time of 8-24 hours.

[0018] Furthermore, the epoxy compound is one of epichlorohydrin, epibromohydrin, ethylene oxide methanol, allyl glycidyl ether, n-butyl glycidyl ether, tert-butyl glycidyl ether, and styrene oxide.

[0019] Furthermore, 6 mg of amine-functionalized mesoporous polymeric ionic liquid with uniform pores needs to be added to 1 mmol of the epoxy compound as a catalyst.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The present invention prepares an amine-functionalized mesoporous polymeric ionic liquid having the characteristics of uniform pores, high active sites and high specific surface area.

[0022] (2) The amine-functionalized mesoporous polymeric ionic liquid prepared by the present invention uses a small amount of amine and can efficiently catalyze the reaction of epoxy compounds with CO under normal pressure, without solvent or catalyst. 2 The reaction synthesizes cyclic carbonate.

[0023] (3) The amine-functionalized mesoporous polymeric ionic liquid with uniform pores prepared by the present invention has stable performance and high active sites after being recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FT-IR spectrum of HPTBB-TMPDA prepared in Example 1 of the present invention;

[0025] Figure 2 N is the HPTBB-TMPDA prepared in Example 1 of the present invention 2 Adsorption-desorption curve diagram;

[0026] Figure 3 This is the pore size distribution diagram of HPTBB-TMPDA prepared in Example 1 of the present invention;

[0027] Figure 4 This is the TGA diagram of HPTBB-TMPDA prepared in Example 1 of the present invention;

[0028] Figure 5 The GCMS spectrum of the cyclic carbonate obtained as the product in Example 1 of the present invention;

[0029] Figure 6 This is the HPTBB-TMPDA sample prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0031] The reagents or instruments used in the present invention without indicating the manufacturer are all conventional products that can be purchased from the market.

[0032] Example 1

[0033] 1. Preparation of amine-functionalized mesoporous polymeric ionic liquids with uniform pores

[0034] 1g nano-SiO 2 (average particle size 100nm) was placed in a 250ml two-necked flask, 100ml 1,2-dichloroethane was added, and ultrasonic dispersion was performed; 1.78g TBB was added, and ultrasonic dissolution was performed, and a magnetic particle of appropriate size was added; it was transferred to an electric heating magnetic stirring device and a condensation reflux device, and 0.81g anhydrous FeCl was added under a nitrogen atmosphere. 3 , heated and stirred, first condensed and refluxed at 45°C for 1h, then heated to 80°C for condensed and refluxed for 1h, cooled to room temperature after the reaction was completed, filtered with methanol 3 times, and then vacuum dried at 80°C overnight to obtain a brown polymer precursor;

[0035] 500 mg of brown polymer precursor was mixed with 41.44 g of 10 wt% HF aqueous solution, stirred at room temperature for 5 h, centrifuged with methanol 3 times, filtered with methanol once, and dried under vacuum at 80° C. overnight to obtain a brown hollow polymer precursor;

[0036] 180 mg of brown hollow polymer precursor was placed in a pressure tube, 5 ml of toluene and 0.78 g of TMPDA were added, and the mixture was stirred at 90 °C for 24 h. After the reaction was completed, it was cooled to room temperature, filtered with methanol three times, and then vacuum dried at 80 °C overnight to obtain an amine-functionalized mesoporous polymer ionic liquid HPTBB-TMPDA with uniform pores.

[0037] 2. Catalytic epoxide and CO 2 Preparation of Cyclic Carbonates by Cycloaddition Reaction

[0038] 30 mg of HPTBB-TMPDA was placed in a Schlenk tube, and then 5 mmol of epichlorohydrin was added. The tube was sealed with a rubber stopper and evacuated with 1 bar CO. 2 The air in the bottle was replaced by gas, and the process was repeated three times. The reaction was carried out in an oil bath at 80°C for 24 hours. After the reaction was completed, the solid catalyst was filtered using methanol for several times and dried in a vacuum drying oven at 80°C to recover the catalyst.

[0039] The chemical reaction equation is as follows:

[0040]

[0041] The filtered reaction solution was diluted with ethyl acetate and quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS). The yield of the prepared target product was 99.1% and the selectivity was 99%.

[0042] Among them, selectivity refers to the ratio of the yield of the target product to the substrate conversion rate, that is, the ratio of the target product to the sum of the main product and the by-product. The higher the selectivity, the fewer by-products and the higher the yield of the target product. The yield is the ratio of the yield of the target product calculated by the chromatographic internal standard method to the theoretical yield.

[0043] Example 2

[0044] The difference from Example 1 is that the epoxy compound used to prepare the cyclic carbonate is epibromopropane. The yield of the prepared target product is 93.6% and the selectivity is 99% through quantitative analysis by GC-MS. The chemical equation of the reaction is as follows:

[0045]

[0046] Example 3

[0047] The difference from Example 1 is that the epoxy compound used in preparing the cyclic carbonate is ethylene oxide methanol, and the quantitative analysis by GC-MS shows that the yield of the prepared target product is 99.8% and the selectivity is 99%.

[0048] The chemical equation for this reaction is as follows:

[0049]

[0050] Example 4

[0051] The difference from Example 1 is that the epoxy compound used in preparing the cyclic carbonate is allyl glycidyl ether, and the quantitative analysis by GC-MS shows that the yield of the prepared target product is 56.7% and the selectivity is 99%.

[0052] The chemical equation for this reaction is as follows:

[0053]

[0054] Example 5

[0055] The difference from Example 1 is that the epoxy compound used in preparing the cyclic carbonate is n-butyl glycidyl ether, and the quantitative analysis by GC-MS shows that the yield of the prepared target product is 38.0% and the selectivity is 99%.

[0056] The chemical equation for this reaction is as follows:

[0057]

[0058] Example 6

[0059] The difference from Example 1 is that the epoxy compound used in preparing the cyclic carbonate is tert-butyl glycidyl ether, and the quantitative analysis by GC-MS shows that the yield of the prepared target product is 47.9% and the selectivity is 99%.

[0060] The chemical equation for this reaction is as follows:

[0061]

[0062] Example 7

[0063] The difference from Example 1 is that the epoxy compound used in preparing the cyclic carbonate is styrene oxide, and the quantitative analysis by GC-MS shows that the yield of the prepared target product is 26.0% and the selectivity is 99%.

[0064] The chemical equation for this reaction is as follows:

[0065]

[0066] Example 8

[0067] The difference from Example 1 is that, in preparing the cyclic carbonate, the reaction temperature is 100° C., the reaction time is 8 h, the yield of the prepared target product is 99.4%, and the selectivity is 99%.

[0068] Example 9

[0069] The difference from Example 1 is that the cyclic carbonate is prepared with a reaction time of 16 h, a yield of the prepared target product of 95.1%, and a selectivity of 99%.

[0070] Example 10

[0071] The difference from Example 1 is that the cyclic carbonate is prepared with a reaction time of 20 h, a yield of the prepared target product of 97.3%, and a selectivity of 99%.

[0072] Comparative Example

[0073] The difference between Comparative Examples 1 to 4 and Example 1 is that the addition amount of the amine-modified precursor TMPDA is 250, 500, 1000 and 2000 μL, respectively, the reaction time for preparing the cyclic carbonate is 8 h, and quantitative analysis is performed by GC-MS. The selectivity and yield data of the target product are shown in Table 1.

[0074] Table 1. Effect of the amount of amine-modified precursor TMPDA added on the catalytic performance of HPTBB-TMPDA catalyst

[0075]

[0076] The difference between Comparative Examples 3, 5 and 6 and Example 1 is that the cyclic carbonate is prepared by changing the reaction time (4-20h), and quantitative analysis is performed by GC-MS. The selectivity and yield data of the target product are shown in Table 2.

[0077] Table 2. Catalytic performance of catalyst HPTBB-TMPDA at different reaction times

[0078]

[0079]

[0080] Comparative Examples 7 to 9 are different from Example 1 in that, in preparing cyclic carbonates, different catalyst amounts (10-40 mg) are used, the reaction time is 8 h, and quantitative analysis is performed by GC-MS. The selectivity and yield data of the target product are shown in Table 3.

[0081] Table 3. Catalytic performance of catalyst HPTBB-TMPDA at different catalyst dosages

[0082] Catalyst dosage (mg) Yield (%) Selectivity (%) Comparative Example 3 30 81.9 99 Comparative Example 7 10 30.6 99 Comparative Example 8 20 65.2 99 Comparative Example 9 40 86.1 99

[0083] The difference between Comparative Examples 10 to 12 and Example 1 is that, in preparing cyclic carbonate, different reaction temperatures (room temperature-100° C.) are changed, the reaction time is 8 h, and quantitative analysis is performed by GC-MS. The selectivity and yield data of the target product are shown in Table 4.

[0084] Table 4. Catalytic performance of catalyst HPTBB-TMPDA at different reaction temperatures

[0085] Reaction temperature (℃) Yield (%) Selectivity (%) Comparative Example 3 80 81.9 99 Comparative Example 10 RT 2.2 99 Comparative Example 11 40 4.3 99 Comparative Example 12 60 30.1 99 Example 8 100 99.4 99

[0086] The catalyst HPTBB-TMPDA recovered after the reaction in Example 1 was used for cyclic catalysis. The number of cycles and the selectivity and yield of the target product are shown in Table 5.

[0087] Table 5. Cyclic catalytic use of catalyst HPTBB-TMPDA

[0088] Number of times HPTBB-TMPDA was used Yield (%) Selectivity (%) Run 1 99.1 99 Run 2 98.5 99 Run 3 97.1 99 Run 4 96.7 99 Run 5 94.0 99 Run 6 90.8 99

[0089] like Figure 1 As shown, the FT-IR spectrum of HPTBB-TMPDA shows that -1 and 2853cm -1 The absorption peak at corresponds to -CH 2 The stretching vibration of the CH bond and the -CH bond between the aromatic ring and the benzyl bromide group 2 The CH bond stretching vibration at 1652cm -1 The absorption peak at 1603 cm -1 and 1456cm -1 The absorption peak at 1081cm -1 The absorption peak at 741cm is the stretching vibration of the CN bond; -1 The peaks around can be attributed to the stretching vibration absorption of the C-Br bond. The above indicates the successful polymerization of the brominated benzyl compound, indicating that the present invention successfully constructs an amine-functionalized polymeric ionic liquid.

[0090] like Figure 2 As shown, the N of HPTBB-TMPDA was determined. 2 Adsorption–desorption curves. Figure 2 The N of HPTBB-TMPDA at 77 K is shown. 2Adsorption capacity. According to IUPAC classification, N 2 The adsorption isotherm shows a combination of type I and type IV. 0 <0.01), N 2 The adsorption capacity of the material increased dramatically, indicating the presence of microporous structures in the material. <P / P 0 <1.0), and there is an obvious hysteresis loop, indicating that the material has a unique mesoporous structure.

[0091] like Figure 3 As shown, the pore size distribution of HPTBB-TMPDA is shown. It can be clearly seen that the pore structure of HPTBB-TMPDA is evenly distributed, basically concentrated around 11 nm, indicating that the present invention successfully constructs an amine-functionalized mesoporous polymeric ionic liquid with uniform pores.

[0092] like Figure 4 As shown in the figure, TGA test shows the excellent thermal stability of HPTBB-TMPDA. When the thermogravimetric loss of the first stage was 5%, the corresponding temperature was 202℃, which was much higher than that of CO 2 The temperature (80°C) of the cycloaddition reaction is considered, so it is suitable as a CO 2 The catalyst is a catalyst for cycloaddition reactions. The thermal stability of the catalyst is also conducive to its recycling.

[0093] Figure 5 The GCMS spectrum of the cyclic carbonate obtained in Example 1 is shown in FIG. Figure 5 As shown, the mixed solution obtained by the reaction of Example 1 was filtered to remove the catalyst, and after dilution with ethyl acetate, GC-MS detection was performed. In the spectrum, 2.5min. is unreacted epichlorohydrin, 5.4min. is the by-product 3-chloro-1,2-propylene glycol, 9.5min. is the product cyclochloropropylene carbonate, and 12.1min. is the internal standard 1,3,5-trimethoxybenzene. Quantification by internal standard method shows that the selectivity of cyclochloropropylene carbonate is 99% and the yield is 99.1%.

[0094] According to the disclosure of the above description, those skilled in the art to which the present invention belongs may also make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A method for preparing an amine-functionalized mesoporous polymeric ionic liquid, characterized in that: The steps include: (1) placing nano-SiO2 and 1,2-dichloroethane in a reaction container, ultrasonically dispersing, adding TBB, and ultrasonically dissolving; adding anhydrous FeCl3 under a nitrogen atmosphere, condensing and reflux at 40-80° C. for 1-3 hours, cooling to room temperature, filtering, and drying to obtain a first polymer precursor; (2) mixing the first polymer precursor with a 10 wt % HF aqueous solution, stirring and dispersing at room temperature, centrifuging, filtering, and drying to obtain a second polymer precursor; (3) placing the second polymer precursor, toluene and TMPDA in a reaction container, heating to 80-100° C. and stirring for 24-48 hours, cooling to room temperature, filtering and drying to obtain an amine-functionalized mesoporous polymerized ionic liquid with uniform pores.

2. The method for preparing an amine-functionalized mesoporous polymeric ionic liquid according to claim 1, characterized in that: The average particle size of the nano-SiO2 is 100nm.

3. The method for preparing an amine-functionalized mesoporous polymeric ionic liquid according to claim 1, characterized in that: In the step (1), 1.0 weight part of nano-SiO2 requires 100 to 150 weight parts of 1,2-dichloroethane for dispersion; The amount of TBB that needs to be added to 1.0 weight part of nano-SiO2 is 1.5-2.0 weight parts; The amount of anhydrous FeCl3 that needs to be added to 1.0 weight part of nano-SiO2 is 0.5-1.0 weight part.

4. The method for preparing an amine-functionalized mesoporous polymeric ionic liquid according to claim 1, characterized in that: In the step (2), 1 part by weight of the first polymer precursor needs to be added with 70 to 90 parts by weight of a 10 wt% HF aqueous solution for mixing.

5. The method for preparing an amine-functionalized mesoporous polymeric ionic liquid according to claim 1, characterized in that: In the step (3), the mass ratio of the second polymer precursor, toluene and TMPDA is 15-20:400-450:70-80.

6. An amine-functionalized mesoporous polymeric ionic liquid, characterized in that: The amine-functionalized mesoporous polymeric ionic liquid is prepared by the preparation method of any one of claims 1 to 5.

7. Use of the amine-functionalized mesoporous polymeric ionic liquid according to claim 6 for catalyzing the reaction of carbon dioxide and epoxy compounds to synthesize cyclic carbonates.

8. The use according to claim 7, characterized in that: The epoxy compound and CO2 are reacted at a reaction pressure of 0.1 MPa, a reaction temperature of 80-100°C, an amine-functionalized mesoporous polymerized ionic liquid is used as a catalyst, and the reaction time is 8-24 hours to catalyze the synthesis of cyclic carbonate.

9. The use according to claim 7, characterized in that: The epoxy compound is one of epichlorohydrin, epibromohydrin, ethylene oxide methanol, allyl glycidyl ether, n-butyl glycidyl ether, tert-butyl glycidyl ether and styrene oxide.

10. The use according to claim 7, characterized in that: The 1 mmol epoxy compound needs to be added with 6 mg of amine-functionalized mesoporous polymeric ionic liquid with uniform pores as a catalyst.

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