Aromatic ring-containing organic imine salt compound catalyst, preparation method thereof and method for preparing cyclic carbonate by catalyzing carbon dioxide

Abstract

The invention provides an aromatic ring-containing organic imine salt compound catalyst, a preparation method thereof and a method for preparing cyclic carbonate by catalyzing carbon dioxide. The preparation method of the aromatic-ring-containing organic imine salt compound catalyst comprises the following steps: adding an organic imine salt dye, a halide salt and a solvent into a container, after stirring reaction is finished, cooling in an ice-water bath, carrying out suction filtration, and drying to obtain the modified aromatic-ring-containing organic imine salt dye catalyst. The invention also discloses a method for preparing cyclic carbonate by catalyzing carbon dioxide by using the aromatic ring-containing organic imine salt compound catalyst. The aromatic ring-containing organic imine salt compound catalyst can significantly improve the yield of cyclic carbonate prepared from carbon dioxide, the reaction condition is mild, no metal or solvent is needed, and meanwhile, the catalyst can be recycled through the nanofiltration process.

Description

Technical Field

[0001] The invention relates to dye catalyst synthesis and catalytic carbon dioxide technology, in particular to an organic imine salt compound catalyst containing an aromatic ring, a preparation method thereof and a method for preparing cyclic carbonate by catalyzing carbon dioxide. Background Art

[0002] The cycloaddition of CO2 and epoxide to generate cyclic carbonates is one of the important ways to achieve carbon cycle. This cycloaddition reaction can not only convert carbon dioxide into chemical products with high added value, but also has very good atom economy, which meets the requirements of green chemistry. Although the current organic dye catalysts have good catalytic activity after structural modification, addition of solvents, addition of HBDs groups and other measures, they still have the following problems:

[0003] (1) The solubility is generally low, and the participation of organic solvents is required to accelerate dissolution and further increase the reaction rate.

[0004] (2) Although the regeneration effect is good and the catalytic performance can be maintained well, the recovery process is cumbersome and needs to be optimized. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method of an organic imine salt compound catalyst containing an aromatic ring, aiming at the problems that the current organic dye catalyst has low solubility, a complicated recovery process, poor selectivity for converting carbon dioxide into chemical products with high added value, low yield and complicated operation. The preparation method is simple, easy to implement and has a high yield. The prepared organic imine salt compound catalyst containing an aromatic ring can significantly improve the yield of preparing cyclic carbonate from carbon dioxide. The reaction conditions are mild and no metal and solvent are required. At the same time, the catalyst can be recycled and reused after a nanofiltration process.

[0006] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing an organic imine salt compound catalyst containing an aromatic ring, comprising the following steps:

[0008] The organic imine salt dye, halide salt and solvent are added into a container, and after the stirring reaction is completed, the container is cooled in an ice water bath, filtered and dried to obtain a modified organic imine salt dye catalyst containing an aromatic ring.

[0009] Further, the organic imine salt dye is a mixture of one or more of Victoria Blue B, Safranine T, Crystal Violet, Basic Red 9, Rhodamine B, Rhodamine 6G and betaine. The organic imine salt dye is preferably a mixture of one or more of Safranine T, Crystal Violet and Basic Red 9.

[0010] Further, the solvent is a mixture of one or more of distilled water, methanol, ethanol, acetonitrile, acetone, tetrahydrofuran, dichloromethane and N,N-dimethylformamide. The solvent is preferably a mixture of one or more of distilled water, acetonitrile and dichloromethane.

[0011] Furthermore, the halide salt is a mixture of one or more of potassium bromide, potassium iodide, sodium bromide, sodium iodide, ammonium bromide, ammonium iodide, copper bromide, copper iodide, magnesium bromide and magnesium iodide; the halide salt is preferably a mixture of one or more of potassium bromide, potassium iodide, sodium bromide and sodium iodide.

[0012] Furthermore, the molar ratio of the organic imine salt dye to the halide salt is 1:1 to 1:200, preferably 1:1 to 1:20. The solvent can dissolve all the organic imine salt dye and the halide salt.

[0013] Furthermore, the reaction temperature is 20-80° C., and the reaction time is 0.5-24 h. Preferably, the reaction temperature is 40-80° C., and the reaction time is 6-18 h.

[0014] Furthermore, the cooling time in the ice water bath is 0.5 to 18 hours, preferably 1 to 5 hours.

[0015] Taking Basic Red 9 modified catalyst as an example, the reaction equation is as follows:

[0016] Another object of the present invention is to disclose an organic imine salt compound catalyst containing an aromatic ring, which is prepared by the above method.

[0017] Another object of the present invention is to disclose a method for preparing cyclic carbonate by catalyzing carbon dioxide with an organic imine salt compound catalyst containing an aromatic ring, comprising the following steps:

[0018] An organic imine salt compound catalyst containing an aromatic ring and propylene oxide are added into a reactor equipped with a stirring device, a temperature sensor and a pressure sensor, and carbon dioxide gas is introduced into the reactor after sealing to heat the reactor for reaction; after the reactor is cooled to room temperature, the remaining carbon dioxide is released; the reactants are filtered, and the solid catalyst obtained by filtration is washed with a solvent, dried and recycled, and the liquid obtained by filtration is separated by reduced pressure distillation to obtain a cyclic carbonate.

[0019] Furthermore, the filtration is nanofiltration.

[0020] Furthermore, the amount of the aromatic ring-containing organic imine salt compound catalyst used is 0.05% to 30% of the amount of propylene oxide used, preferably 0.5% to 5%.

[0021] Furthermore, the pressure of carbon dioxide in the reactor is 0.5-10 MPa, preferably 1-5 MPa.

[0022] Furthermore, the reaction temperature is 20-200° C., and the reaction time is 0.5-24 h. Preferably, the reaction temperature is 80-150° C., and the reaction time is 6-18 h.

[0023] Taking the organic imine salt dye catalyst modified by Basic Red 9 as an example, the reaction equation is as follows:

[0024]

[0025] The present invention discloses an organic imine salt compound catalyst containing an aromatic ring, a preparation method thereof and a method for preparing cyclic carbonate by catalyzing carbon dioxide, which has the following advantages compared with the prior art:

[0026] 1) The method for preparing the aromatic ring-containing organic imine salt compound catalyst of the present invention is simple, easy to operate, has a high yield, and can be applied to the preparation of cyclic carbonates from carbon dioxide.

[0027] 2) Compared with traditional catalysts, the aromatic ring-containing organic imine salt compound catalyst of the present invention realizes the highly selective catalytic synthesis of cyclic carbonates under mild, metal-free and solvent-free conditions, exhibits excellent adsorption and conversion dual functionality for carbon dioxide, and has strong market prospects.

[0028] 3) The aromatic ring-containing organic imine salt compound catalyst of the present invention is easy to recycle, which is beneficial to the recycling of the catalyst and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a scanning electron microscope image of the Safflower T modified catalyst of Example 1;

[0030] Figure 2 This is the infrared spectrum of the modified catalyst of Safflower T in Example 1;

[0031] Figure 3 is the NMR spectrum of propylene carbonate of Example 1;

[0032] Figure 4 is a scanning electron microscope image of the Basic Red 9 modified catalyst of Example 2;

[0033] Figure 5 This is the infrared spectrum of the Basic Red 9 modified catalyst in Example 2. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0035] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0036] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0037] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0038] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0039] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0040] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0041] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0042] Example 1

[0043] This embodiment discloses an organic imine salt compound catalyst containing an aromatic ring, and a method for preparing a cyclic carbonate by catalyzing carbon dioxide using the catalyst, the method being as follows:

[0044] The synthesis method of the modified catalyst of Safranine T is as follows: 2 mmol (0.702 g) of Safranine T and 2.2 mmol (0.365 g) of KI (1.1 eq.) are added to a 100 mL round-bottom flask, and 50 mL of deionized water is added, and the mixture is stirred and refluxed at 60°C for 1 h, and the speed is set at 600 r / min. The round-bottom flask is then placed in an ice water bath for 1 h, and then filtered with a Buchner funnel to obtain a large amount of solids, which are then washed with deionized water several times, and dried in an oven to obtain the organic dye catalyst Safranine TI, which is then placed in a dryer for standby use.

[0045] Catalyst characterization: Transmission electron microscopy (TEM) Figure 1 ), it can be observed that the prepared catalyst has a porous structure with a specific surface area of ​​10.2m2 / g, and the rough surface is conducive to the exposure of surface functional groups and accelerates the catalytic rate. The structure of the catalyst can be qualitatively analyzed by infrared spectroscopy ( Figure 2 , a is Safranine T, b is modified Safranine T).

[0046] Preparation of cyclic carbonates from carbon dioxide using a modified catalyst of Safflower T: Safflower TI (0.2 mmol) and propylene oxide (20 mmol) were added to a reactor equipped with a magnet, a temperature sensor and a pressure sensor, and the high-pressure reactor was quickly sealed. The air inlet valve was then opened, and 1.5 MPa of carbon dioxide gas was added to the reactor. The reactor was heated to 80°C and reacted for 6 hours. The reaction was as shown in Formula 1. After the reaction was completed, the reactor was naturally cooled to room temperature, and the exhaust valve was gently opened to slowly release the remaining carbon dioxide. The solution sample was filtered, and the solid catalyst was washed and dried with a solvent for multiple times for recycling. The liquid was separated by reduced pressure distillation to obtain the product propylene carbonate (yield 58%). The spectrum is shown in the figure. Figure 3 As shown, it can be seen that the newly synthesized modified organic imide dye catalyst can efficiently catalyze carbon dioxide to prepare cyclic carbonate.

[0047]

[0048] Example 2

[0049] This embodiment discloses an organic imine salt compound catalyst containing an aromatic ring, and a method for preparing a cyclic carbonate by catalyzing carbon dioxide using the catalyst, the method being as follows:

[0050] Synthesis of modified catalyst of basic red 9: 2mmol (0.6476g) of basic red 9 and 2mmol (0.189g) of 3-chloropropanol were dissolved in 25mL of anhydrous ethanol. 2mmol (0.08g) of NaOH was added to absorb the hydrogen chloride produced by the reaction and promote the reaction. The mixture was heated to 70°C and stirred for 24h under the condition of reflux of condensed water. A rotary evaporator was then used to heat to 35°C to remove the ethanol solvent from the obtained dark red mixed solution. Subsequently, the mixture was rinsed with deionized water several times to dissolve the residual 3-chloropropanol on the surface of the solid. The mixture was then filtered and washed with a solvent. Finally, the solid was dried in an oven and recrystallized with acetonitrile. The intermediate compound was filtered to obtain a black powder and dried in an oven for later use.

[0051] A black powder solid and 2.2 mmol (0.365 g) of KI (1.1 eq) were added to a 100 mL round-bottom flask, and 50 mL of deionized water were added. The mixture was stirred and refluxed for 1 h at 60 ° C. The speed was set to 600 r / min. The round-bottom flask was then placed in an ice-water bath for 1 h, and then filtered with a Buchner funnel to obtain a large amount of solid, which was washed with deionized water several times. After being dried in an oven, the organic dye catalyst basic red 9-n-propanol-I was obtained, and then placed in a dryer for standby use. The synthesis route of the catalyst basic red 9-n-propanol-I is shown in Formula 2.

[0052]

[0053] Catalyst characterization: Transmission electron microscopy (TEM) Figure 4 ), it can be observed that the prepared catalyst has a sheet-like stacking and porous structure with a specific surface area of ​​11.9m 2 / g, and the rough surface of the flake structure is conducive to the exposure of surface functional groups and accelerates the catalytic rate. The structure of the catalyst can be qualitatively analyzed by infrared spectroscopy ( Figure 5 ).

[0054] The organic dye catalyst Basic Red 9-n-propanol-I catalyst is used to catalyze carbon dioxide to prepare cyclic carbonate: Basic Red 9-n-propanol-I catalyst (0.4mmol) and propylene oxide (20mmol) are added to a reactor equipped with a magnet, a temperature sensor and a pressure sensor, and the high-pressure reactor is quickly sealed. Then the air inlet valve is opened, 3MPa of carbon dioxide gas is added to the reactor, and the reactor is heated to 120°C for 12h. The reaction is as shown in Formula 1. After the reaction is completed, wait for the reactor to cool naturally to room temperature, then gently open the exhaust valve to slowly release the remaining carbon dioxide. The solution sample is filtered, and the solid catalyst is washed and dried with a solvent for multiple times for recycling. The liquid is separated by vacuum distillation to obtain the product propylene carbonate (yield 77%), as shown in the spectrum. Figure 3 As shown, it can be seen that the newly synthesized modified organic imide dye catalyst can efficiently catalyze carbon dioxide to prepare cyclic carbonate.

[0055] Comparative Example 1

[0056] Comparative Example 1 uses unmodified dye to catalyze carbon dioxide to prepare cyclic carbonate. Safflower T (0.2 mmol) and propylene oxide (20 mmol) are added to a reactor equipped with a magnet, a temperature sensor and a pressure sensor, and the high-pressure reactor is quickly sealed. Then the air inlet valve is opened, 1.5 MPa of carbon dioxide gas is added to the reactor, and the reactor is heated to 80°C for 6 hours. The reaction is as shown in Formula 1. After the reaction is completed, after the reactor is naturally cooled to room temperature, the exhaust valve is gently opened to slowly release the remaining carbon dioxide. The solution sample is filtered, and the solid catalyst is washed and dried with a solvent for multiple times for recycling. The liquid is separated by vacuum distillation to obtain the product propylene carbonate (yield 7%).

[0057] By comparing Example 1 with Control Example 1, it can be seen that the yield of propylene carbonate is increased from 7% to 58%. Therefore, the modified organic imine salt dye catalyst has a good application prospect in catalyzing carbon dioxide conversion.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an organic imine salt compound catalyst containing an aromatic ring, characterized in that: The following steps are involved: The organic imine salt dye, halide salt and solvent are added into a container, and after the stirring reaction is completed, the container is cooled in an ice water bath, filtered and dried to obtain a modified organic imine salt dye catalyst containing an aromatic ring.

2. The method for preparing the aromatic ring-containing organic imine salt compound catalyst according to claim 1, characterized in that: The organic imine salt dye is a mixture of one or more of Victoria Blue B, Safranine T, Crystal Violet, Basic Red 9, Rhodamine B, Rhodamine 6G and betaine; and / or, the solvent is a mixture of one or more of distilled water, methanol, ethanol, acetonitrile, acetone, tetrahydrofuran, dichloromethane and N,N-dimethylformamide; And / or, the halide salt is a mixture of one or more of potassium bromide, potassium iodide, sodium bromide, sodium iodide, ammonium bromide, ammonium iodide, copper bromide, copper iodide, magnesium bromide and magnesium iodide.

3. The method for preparing the aromatic ring-containing organic imine salt compound catalyst according to claim 1, characterized in that: The molar ratio of the organic imine salt dye to the halide salt is 1:1 to 1:

200.

4. The method for preparing the aromatic ring-containing organic imine salt compound catalyst according to claim 1, characterized in that: The reaction temperature is 20-80° C., and the reaction time is 0.5-24 h.

5. The method for preparing the aromatic ring-containing organic imine salt compound catalyst according to claim 1, characterized in that: The cooling time in the ice water bath is 0.5 to 18 hours.

6. An aromatic ring-containing organic imine salt compound catalyst prepared by the method according to any one of claims 1 to 5.

7. A method for preparing cyclic carbonates by catalyzing carbon dioxide with the aromatic ring-containing organic imine salt compound catalyst according to claim 6, characterized in that: The following steps are involved: An organic imine salt compound catalyst containing an aromatic ring and propylene oxide are added into a reactor equipped with a stirring device, a temperature sensor and a pressure sensor, and carbon dioxide gas is introduced into the reactor after sealing to heat the reactor for reaction; after the reactor is cooled to room temperature, the remaining carbon dioxide is released; the reactants are filtered, and the solid catalyst obtained by filtration is washed with a solvent, dried and recycled, and the liquid obtained by filtration is separated by reduced pressure distillation to obtain a cyclic carbonate.

8. The method for preparing cyclic carbonate by catalyzing carbon dioxide with an organic imine salt compound catalyst containing an aromatic ring according to claim 7, characterized in that: The amount of the aromatic ring-containing organic imine salt compound catalyst used is 0.05% to 30% of the amount of propylene oxide used.

9. The method for preparing cyclic carbonate by catalyzing carbon dioxide with an organic imine salt compound catalyst containing an aromatic ring according to claim 7, characterized in that: The pressure of carbon dioxide in the reactor is 0.5-10 MPa.

10. The method for preparing cyclic carbonate by catalyzing carbon dioxide with an organic imine salt compound catalyst containing an aromatic ring according to claim 7, characterized in that: The reaction temperature is 25-120° C., and the reaction time is 0.5-24 h.

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