A transition metal-supported nitrogen-rich carbon-based composite material and its preparation method and application

Abstract

The present invention discloses a transition metal-supported nitrogen-rich carbon-based composite material, a preparation method thereof, and an application thereof. The composite material is prepared by calcining a transition metal halide and a nitrogen-rich polymer after an adsorption complexation reaction, and can be used as a catalyst in a carbon dioxide cycloaddition reaction. The preparation method adopted by the present invention is simple and low in cost. The metal and nitrogen active centers are evenly dispersed, the controllability is strong, the catalyst is stable and reliable, and the applicability is strong. An efficient cycloaddition reaction of carbon dioxide and epoxide can be achieved under a wide range of reaction conditions. The present invention overcomes the technical difficulties of low catalytic efficiency, complex preparation process, and unstable active center support of homogeneous catalysts used in existing cycloaddition reactions, providing a new approach for green and efficient carbon dioxide cycloaddition reactions and having great practical application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a transition metal-supported nitrogen-rich carbon-based composite material, a preparation method thereof, and applications thereof. Background Art

[0002] The rapid development of global industrialization and the rise in population have led to excessive consumption of fossil fuels and increasing carbon dioxide emissions, which in turn have exacerbated the problem of global warming. The increasingly serious environmental pollution and energy shortages have gradually attracted the attention of the international community and governments around the world. Currently, CO2 capture and storage technology is an important means to address the problem of carbon emissions internationally. From a resource perspective, CO2 is the world's most abundant, cheap, and abundant carbon one (C1) resource. Vigorously developing CO2 resource utilization technology, recovering, fixing, and utilizing CO2 as a resource, and increasing the added value of products are of great economic and environmental significance. However, due to the high kinetic and thermodynamic stability of CO2 molecules, a large amount of energy is required for activation and conversion. Therefore, the development of low-cost, high-efficiency CO2 capture and conversion (C3) strategies is a current research hotspot for researchers. Among the many CO2 conversion strategies, the cycloaddition reaction of CO2 and epoxides to produce cyclic carbonates has significant advantages. This reaction not only has atom economy (atomic utilization rate reaches 100%) and high carbon fixation, but can also produce high-value-added chemicals based on green chemistry, effectively realizing the recycling of carbon resources, which is of great significance to the sustainable development of society.

[0003] Currently, homogeneous catalysts such as ionic liquids, metalloporphyrins, metal complexes, phosphates, and quaternary ammonium salts can effectively catalyze and activate the cycloaddition reaction of carbon dioxide with epoxides. However, the inherent difficulty in separating and purifying homogeneous catalysts limits their industrial application. To address this issue, researchers have developed a series of heterogeneous catalysts that are easily separated and reused by dispersing and immobilizing homogeneous active centers onto suitable support materials. For example, Chinese patent CN109365002A discloses a method for using a magnetic ionic liquid-supported catalyst in the cycloaddition reaction of carbon dioxide; Chinese patent CN106008448A discloses a method for catalyzing the cycloaddition reaction of a ternary heterocyclic compound with carbon dioxide; Chinese patent CN111790438A discloses a catalyst for the cycloaddition reaction of ethylene oxide and carbon dioxide, its preparation method, and its application; and Chinese patent CN113912805A discloses an organic porous polymer for catalyzing the cycloaddition reaction of epoxides with carbon dioxide. Although various homogeneous catalysts have been developed, they still face huge challenges such as low catalytic activity, complex preparation process, and unstable immobilization of active centers, which are technical problems that need to be solved urgently in this field. Summary of the Invention

[0004] Purpose of the invention: In order to solve the technical problems existing in the prior art, the present invention aims to provide a transition metal-supported nitrogen-rich carbon-based composite material that can be used to catalyze the cycloaddition reaction of carbon dioxide and epoxy compounds, has high catalytic effect, simple preparation process and good stability. In addition, the present invention also provides a preparation method of the transition metal-supported nitrogen-rich carbon-based composite material.

[0005] Technical solution: The transition metal-immobilized nitrogen-rich carbon-based composite material of the present invention is prepared by calcining a transition metal halide and a nitrogen-rich polymer after adsorption and complexation reaction.

[0006] Furthermore, the mass ratio of the transition metal halide to the nitrogen-rich polymer is 0.5-3:10; the transition metal contained in the transition metal halide is magnesium, aluminum, iron, cobalt, nickel, copper or zinc, and the halogen element contained in the transition metal halide is fluorine, chlorine, bromine or iodine; and the nitrogen-rich polymer is one or more of polyaniline, polypyrrole, polyacrylonitrile, polyvinylpyrrolidone or polyimide.

[0007] The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0008] (1) dispersing a transition metal halide and a nitrogen-rich polymer in a solvent, performing an adsorption complexation reaction, and then evaporating the solvent to obtain a composite material of the transition metal halide and the nitrogen-rich polymer;

[0009] (2) The composite material of the transition metal halide and the nitrogen-rich polymer is calcined to obtain a transition metal-supported nitrogen-rich carbon-based composite material.

[0010] Furthermore, in step (1), the solvent is anhydrous ethanol, and the conditions of the adsorption complexation reaction are: temperature of 20-30° C. and time of 3-5 h.

[0011] Furthermore, in step (2), the calcination treatment conditions are: temperature of 300-600° C., and holding time of 1-3 hours.

[0012] The present invention discloses an application of the transition metal-supported nitrogen-rich carbon-based composite material as a catalyst in a carbon dioxide cycloaddition reaction. The application method comprises the following steps: adding the transition metal-supported nitrogen-rich carbon-based composite material, a co-catalyst and an epoxy compound into a high-pressure reactor, sealing and stirring the mixture, introducing carbon dioxide and carrying out a catalytic reaction to obtain a cyclocarbonate.

[0013] Furthermore, the co-catalyst is tetrabutylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium iodide; the epoxy compound is propylene oxide, butylene oxide, epichlorohydrin, styrene oxide or butyl glycidyl ether; and the conditions of the catalytic reaction are: stirring speed of 100-300 rpm, charging of 1-3 MPa carbon dioxide, reaction temperature of 60-150° C., and reaction time of 2-10 h.

[0014] Furthermore, the mass ratio of the transition metal-supported nitrogen-rich carbon-based composite material to the co-catalyst is 1-10:1, preferably 1-5:1.

[0015] Furthermore, the usage ratio of the transition metal-immobilized nitrogen-rich carbon-based composite material to the epoxy compound is 0.5-7.5 mg:1 mmol, which is conducive to the efficient catalytic conversion of the epoxy compound.

[0016] Reaction principle: The present invention uses transition metal atoms as catalytic active centers and nitrogen-rich polymers as carbon source precursors. The metal elements are dispersed and immobilized on the polymer surface through simple adsorption and complexation. At the same time, by adjusting the amount of active substances and the calcination temperature, a nitrogen-rich carbon-based catalyst with uniform transition metal immobilization is obtained. During the pyrolysis and carbonization process, the nitrogen element is uniformly doped in situ. The dispersion and stability of the nitrogen active sites are significantly better than those of nitrogen-rich hybrid carbon prepared by the external nitrogen source method. At the same time, the formation of MN (M = transition metal element) metal bonds during the pyrolysis process realizes the uniform and stable immobilization of the metal active center. The one-step pyrolysis completes the synergistic construction of the Lewis acid-base active site. It is found that this series of catalysts can cooperate with co-catalysts to realize efficient cycloaddition catalytic reactions of carbon dioxide and epoxy compounds under solvent-free conditions. The operation is simple, the controllability is strong, and the cost investment is low. It provides a new idea for the preparation of carbon dioxide cycloaddition reaction catalysts and has great practical application prospects.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) simple preparation and low cost, and the metal active sites of the prepared catalyst are evenly dispersed and highly stable; (2) the synergistic construction of Lewis acid-base active sites accelerates the catalytic activation process of carbon dioxide and epoxy compounds; (3) the amount of metal overflow is low, and the catalyst has excellent reusability and universal performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The reusability of the transition metal-supported nitrogen-rich carbon-based material prepared in Example 11 of the present invention as a catalyst;

[0019] Figure 2 This is a graph showing the efficiency of the cycloaddition reaction of different epoxides with carbon dioxide catalyzed by the transition metal-supported nitrogen-rich carbonyl prepared in Examples 10 to 14 of the present invention;

[0020] Figure 3 This is a SEM image of the transition metal-supported nitrogen-rich carbon-based composite material prepared in Example 15 of the present invention;

[0021] Figure 4 This is a diagram showing the effect of catalyzing the cycloaddition reaction of propylene oxide and carbon dioxide using transition metal-supported nitrogen-rich carbon-based catalysts prepared by calcining at different temperatures in Examples 15 to 17 of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below with reference to specific embodiments and accompanying drawings.

[0023] Example 1: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0024] (1) Dispersing zinc fluoride and polyaniline precursor in an anhydrous ethanol solution at a mass ratio of 2:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc fluoride-loaded polyaniline composite precursor;

[0025] (2) The zinc chloride-loaded polyaniline composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0026] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction. The steps were as follows: 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 20 mg of the co-catalyst tetrabutylammonium bromide, and 50 mmol of propylene oxide were added to a high-pressure reactor, the mixture was sealed and stirred, the speed was set to 300 rpm, 2 MPa of carbon dioxide was introduced, the reaction temperature was set to 120°C, and the reaction was carried out for 5 hours to generate propylene carbonate with a yield of 93%.

[0027] Example 2: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0028] (1) Copper chloride and polypyrrole precursor were dispersed in an anhydrous ethanol solution at a mass ratio of 1:10 and ultrasonicated for 30 minutes. Then, the mixture was mixed and immersed under magnetic stirring at 25°C for 4 hours, and the ethanol solution was evaporated to dryness. The copper chloride-loaded polypyrrole composite precursor was collected by grinding;

[0029] (2) The copper chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 500°C and kept warm for 2 hours, and naturally cooled to room temperature to obtain a copper-loaded nitrogen-rich carbon-based composite material.

[0030] A copper-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 50 mg of the copper-supported nitrogen-rich carbon-based composite material, 50 mg of a co-catalyst tetrabutylammonium iodide, and 100 mmol of butylene oxide to a high-pressure reactor, sealing and stirring the reaction mixture, setting the rotation speed to 200 rpm, introducing 3 MPa of carbon dioxide, setting the reaction temperature to 100° C., and reacting for 8 hours to generate butylene carbonate with a yield of 89.4%.

[0031] Example 3: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0032] (1) Nickel bromide and polyacrylonitrile precursor were dispersed in an anhydrous ethanol solution at a mass ratio of 0.5:10 and ultrasonicated for 30 minutes. Then, the mixture was mixed and immersed under magnetic stirring at 25°C for 4 hours, and the ethanol solution was evaporated to dryness. The nickel bromide-loaded polyacrylonitrile composite precursor was collected by grinding;

[0033] (2) The nickel bromide-loaded polyacrylonitrile composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 400°C and kept warm for 2 hours, and naturally cooled to room temperature to obtain a nickel-supported nitrogen-rich carbon-based composite material.

[0034] A nickel-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction. The steps were as follows: 80 mg of the nickel-supported nitrogen-rich carbon-based composite material, 40 mg of a co-catalyst tetrabutylammonium chloride, and 70 mmol of styrene oxide were added to a high-pressure reactor. The sealed stirring speed was set to 280 rpm, 2.5 MPa of carbon dioxide was introduced, the reaction temperature was set to 110° C., and the reaction was carried out for 7 hours to generate styrene cyclic carbonate with a yield of 98.2%.

[0035] Example 4: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0036] (1) Magnesium fluoride and polyvinyl pyrrolidone precursor were dispersed in an anhydrous ethanol solution at a mass ratio of 1.2:10 and ultrasonicated for 30 minutes. Then, the mixture was mixed and immersed under magnetic stirring at 25°C for 4 hours, and the ethanol solution was evaporated to dryness. The magnesium fluoride-loaded polyvinyl pyrrolidone composite precursor was obtained by grinding and collecting.

[0037] (2) The magnesium fluoride-loaded polyvinyl pyrrolidone composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 450° C. and kept warm for 2 hours, and naturally cooled to room temperature to obtain a magnesium-supported nitrogen-rich carbon-based composite material.

[0038] A magnesium-supported nitrogen-rich carbon-based composite material is used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 65 mg of a magnesium-supported nitrogen-rich carbon-based composite catalyst, 30 mg of a co-catalyst tetrabutylammonium iodide, and 20 mmol of epichlorohydrin to a high-pressure reactor, sealing and stirring the reaction mixture at a speed of 180 rpm, introducing 1 MPa of carbon dioxide, setting the reaction temperature at 60° C., and reacting for 3 hours to generate chloropropylene carbonate with a yield of 93.8%.

[0039] Example 5: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0040] (1) Aluminum chloride and polyimide precursor were dispersed in an anhydrous ethanol solution at a mass ratio of 0.65:10 and ultrasonicated for 30 minutes. The mixture was then mixed and immersed under magnetic stirring at 25°C for 4 hours, and the ethanol solution was evaporated to dryness. The aluminum chloride-loaded polyimide composite precursor was obtained by grinding and collecting.

[0041] (2) The aluminum chloride-loaded polyimide composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 380° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain an aluminum-supported nitrogen-rich carbon-based composite material.

[0042] An aluminum-supported nitrogen-rich carbon-based composite material is used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 50 mg of an aluminum-supported nitrogen-rich carbon-based composite material, 10 mg of a co-catalyst tetrabutylammonium iodide, and 10 mmol of butyl glycidyl ether to a high-pressure reactor; setting the sealed stirring speed to 100 rpm; introducing 3 MPa of carbon dioxide; setting the reaction temperature to 150° C.; and reacting for 10 hours to generate butyl glycidyl ether cyclocarbonate with a yield of 88.6%.

[0043] Example 6: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0044] (1) Dispersing ferric chloride and polyaniline precursor in an anhydrous ethanol solution at a mass ratio of 1.8:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a ferric chloride-loaded polyaniline composite precursor;

[0045] (2) The ferric chloride-loaded polyaniline composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined to 600° C. in a tube furnace under argon protection and kept warm for 2 h, and naturally cooled to room temperature to obtain an iron-loaded nitrogen-rich carbon-based composite material.

[0046] An iron-supported nitrogen-rich carbon-based composite material is used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 75 mg of the iron-supported nitrogen-rich carbon-based composite material, 30 mg of a co-catalyst tetrabutylammonium bromide, and 10 mmol of epichlorohydrin to a high-pressure reactor, sealing and stirring the reaction mixture, setting the rotation speed to 160 rpm, introducing 1.5 MPa of carbon dioxide, setting the reaction temperature to 110° C., and reacting for 3 hours to generate chloropropylene carbonate with a yield of 99.2%.

[0047] Example 7: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0048] (1) Cobalt chloride and polypyrrole precursor were dispersed in an anhydrous ethanol solution at a mass ratio of 1:10 and ultrasonicated for 30 minutes, then mixed and immersed under magnetic stirring at 25°C for 4 hours, and then the ethanol solution was evaporated to dryness, and the cobalt chloride-loaded polypyrrole composite precursor was obtained by grinding and collecting;

[0049] (2) The cobalt chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 420° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a cobalt-loaded nitrogen-rich carbon-based composite material.

[0050] A cobalt-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 90 mg of the cobalt-supported nitrogen-rich carbon-based composite material, 50 mg of a co-catalyst tetrabutylammonium chloride, and 100 mmol of propylene oxide to a high-pressure reactor, sealing and stirring the reaction mixture, setting the speed to 200 rpm, introducing 2.0 MPa of carbon dioxide, setting the reaction temperature to 120° C., and reacting for 5 hours to generate propylene carbonate with a yield of 94.6%.

[0051] Example 8: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0052] (1) Dispersing zinc bromide and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 0.8:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc bromide-loaded polypyrrole composite precursor;

[0053] (2) The zinc bromide-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 480° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0054] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction, comprising the following steps: adding 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 25 mg of the co-catalyst tetrabutylammonium iodide, and 100 mmol of epichlorohydrin to a high-pressure reactor, sealing and stirring the reaction mixture, setting the speed to 200 rpm, introducing 1.8 MPa of carbon dioxide, setting the reaction temperature to 90° C., and reacting for 4 hours to generate chloropropylene carbonate with a yield of 92.6%.

[0055] Example 9: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0056] (1) Dispersing zinc iodide and polyimide precursor in an anhydrous ethanol solution at a mass ratio of 0.7:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc iodide-loaded polyimide composite precursor;

[0057] (2) The zinc iodide-loaded polyimide composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 360° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0058] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 40 mg of the zinc-supported nitrogen-rich carbon-based composite material, 20 mg of a co-catalyst tetrabutylammonium bromide, and 70 mmol of butylene oxide to a high-pressure reactor, sealing and stirring the reaction mixture, setting the speed to 150 rpm, introducing 2.5 MPa of carbon dioxide, setting the reaction temperature to 110° C., and reacting for 6 hours to generate butylene carbonate with a yield of 95.7%.

[0059] Example 10: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0060] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1.5:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0061] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0062] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of a co-catalyst tetrabutylammonium bromide, and 70 mmol of epichlorohydrin to a high-pressure reactor, sealing and stirring the reaction mixture, setting the speed to 200 rpm, introducing 2 MPa of carbon dioxide, setting the reaction temperature to 120° C., and reacting for 2 h to generate chloropropylene carbonate with a yield of 95.7%.

[0063] Example 11: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0064] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1.5:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0065] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0066] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction, comprising the following steps: adding 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of the co-catalyst tetrabutylammonium bromide, and 70 mmol of propylene oxide to a high-pressure reactor, sealing and stirring the reaction mixture, setting the speed to 200 rpm, introducing 2 MPa of carbon dioxide, setting the reaction temperature to 120° C., and reacting for 5 hours to generate propylene carbonate with a yield of 98.1%.

[0067] The catalyst zinc-supported nitrogen-rich carbon-based composite material prepared in Example 11 was subjected to a repeated use performance test, and the results were as follows: Figure 1 As shown in the figure, it can be seen that after the catalyst is recycled for 5 times, its catalytic performance can still reach 82.1% under the same reaction conditions, indicating that the catalyst has good reusability.

[0068] Example 12: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0069] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1.5:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0070] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0071] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction. The steps were as follows: 100 mg of a zinc-supported nitrogen-rich carbon-based composite material, 10 mg of a co-catalyst tetrabutylammonium bromide, and 70 mmol of butylene oxide were added to a high-pressure reactor. The mixture was sealed and stirred at a speed of 200 rpm. 2 MPa of carbon dioxide was introduced, the reaction temperature was set at 120° C., and the reaction was carried out for 6 hours to generate butylene carbonate with a yield of 94.5%.

[0072] Example 13: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0073] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1.5:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0074] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0075] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction, comprising the following steps: adding 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of the co-catalyst tetrabutylammonium bromide, and 70 mmol of styrene oxide to a high-pressure reactor, sealing and stirring the reaction vessel, setting the speed to 200 rpm, introducing 2 MPa of carbon dioxide, setting the reaction temperature to 120° C., and reacting for 8 hours to generate styrene cyclic carbonate with a yield of 77.4%.

[0076] Example 14: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0077] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1.5:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0078] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0079] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for a carbon dioxide cycloaddition reaction, comprising the following steps: adding 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of a co-catalyst tetrabutylammonium bromide, and 70 mmol of styrene oxide to a high-pressure reactor, sealing and stirring the reaction vessel, setting the speed to 200 rpm, introducing 2 MPa of carbon dioxide, setting the reaction temperature to 120° C., and reacting for 12 hours to generate butyl glycidyl ether cyclocarbonate with a yield of 87.4%.

[0080] The results of Example 10-Example 14 are as follows Figure 2 As shown in the figure, it can be seen that under the same experimental conditions, the zinc-supported nitrogen-rich carbon-based composite material has different catalytic effects on different epoxides, indicating that the catalytic system has a certain selectivity.

[0081] Example 15: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0082] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0083] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 300° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0084] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction. The steps were as follows: 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of the co-catalyst tetrabutylammonium bromide, and 70 mmol of propylene oxide were added to a high-pressure reactor, the mixture was sealed and stirred, the speed was set to 200 rpm, 2 MPa of carbon dioxide was introduced, the reaction temperature was set to 120°C, and the reaction was carried out for 3 hours to generate propylene carbonate with a yield of 85.6%.

[0085] The zinc-supported nitrogen-rich carbon-based composite material prepared in Example 15 was characterized by SEM. Figure 3 As shown in the figure, it can be seen that the zinc-supported nitrogen-rich carbon-based composite material presents a uniform spherical morphology, and the overall particle size is less than 1um.

[0086] Example 16: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0087] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0088] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 400° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0089] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction. The steps were as follows: 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of the co-catalyst tetrabutylammonium bromide, and 70 mmol of propylene oxide were added to a high-pressure reactor, the mixture was sealed and stirred, the speed was set to 200 rpm, 2 MPa of carbon dioxide was introduced, the reaction temperature was set to 120°C, and the reaction was carried out for 3 hours to generate propylene carbonate with a yield of 58.9%.

[0090] Example 17: The method for preparing the transition metal-supported nitrogen-rich carbon-based composite material of the present invention comprises the following steps:

[0091] (1) Dispersing zinc chloride and polypyrrole precursor in an anhydrous ethanol solution at a mass ratio of 1:10 and ultrasonicating for 30 minutes, then mixing and immersing under magnetic stirring at 25°C for 4 hours, evaporating the ethanol solution, and grinding and collecting to obtain a zinc chloride-loaded polypyrrole composite precursor;

[0092] (2) The zinc chloride-loaded polypyrrole composite precursor obtained in step (1) is transferred to a porcelain ark, pyrolyzed and calcined in a tube furnace under argon protection to 500° C. and kept warm for 2 h, and then naturally cooled to room temperature to obtain a zinc-loaded nitrogen-rich carbon-based composite material.

[0093] A zinc-supported nitrogen-rich carbon-based composite material was used as a catalyst for the carbon dioxide cycloaddition reaction. The steps were as follows: 100 mg of the zinc-supported nitrogen-rich carbon-based composite material, 10 mg of the co-catalyst tetrabutylammonium bromide, and 70 mmol of propylene oxide were added to a high-pressure reactor, the mixture was sealed and stirred, the speed was set to 200 rpm, 2 MPa of carbon dioxide was introduced, the reaction temperature was set to 120°C, and the reaction was carried out for 3 hours to generate propylene carbonate with a yield of 51.6%.

[0094] The catalytic results of Example 15-Example 17 are as follows Figure 4 As shown by Figure 4It can be seen that: with the increase of calcination temperature, the catalytic performance of zinc-supported nitrogen-rich carbon-based composite materials gradually decreases, which shows that too high temperature is not conducive to the performance improvement of the catalyst.

[0095] Comparative Example 1: A nitrogen-rich polymer is used to directly catalyze the carbon dioxide cycloaddition reaction. The preparation method of the nitrogen-rich carbon-based catalytic material described in the present invention includes the following steps: transferring a pure polypyrrole precursor into a porcelain ark, pyrolyzing and calcining it in a tubular furnace under argon protection to 300°C and keeping it warm for 2 hours, and naturally cooling it to room temperature to obtain a nitrogen-rich carbon-based catalytic material.

[0096] A nitrogen-rich carbon-based catalytic material is used as a catalyst for the carbon dioxide cycloaddition reaction, and the steps are as follows: 100 mg of the nitrogen-rich carbon-based catalytic material, 10 mg of the co-catalyst tetrabutylammonium bromide, and 70 mmol of propylene oxide are added to a high-pressure reactor, the mixture is sealed and stirred, the speed is set to 200 rpm, 2 MPa of carbon dioxide is introduced, the reaction temperature is set to 120° C., and the reaction is carried out for 3 hours to generate propylene carbonate with a yield of 27.6%.

Claims

1. A Zn metal catalyzing carbon dioxide cycloaddition reaction immobilized on a nitrogen-rich carbon-based composite material, characterized in that: The composite material is prepared by calcining after adsorption and complexation reaction between metal Zn halide and nitrogen-rich polymer. The nitrogen-rich polymer is one or more of polyaniline, polypyrrole, polyacrylonitrile, polyvinyl pyrrolidone or polyimide. The calcination temperature is 300°C.

2. The composite material according to claim 1, characterized in that The mass ratio of the metal Zn halide to the nitrogen-rich polymer is 0.5-3:

10.

3. The composite material according to claim 1, characterized in that The halogen element contained in the metal Zn halide is fluorine, chlorine, bromine or iodine.

4. The composite material according to claim 1, characterized in that The steps of catalyzing the carbon dioxide cycloaddition reaction are: adding metal Zn immobilized on a nitrogen-rich carbon-based composite material, a co-catalyst and an epoxy compound into a high-pressure reactor, sealing and stirring, injecting carbon dioxide, and performing a catalytic reaction to obtain a cyclocarbonate.

5. The composite material according to claim 4, characterized in that The epoxy compound is propylene oxide, butylene oxide, epichlorohydrin, styrene oxide or butyl glycidyl ether.

6. A method for preparing the composite material according to claim 1, characterized in that: The following steps are involved: (1) Dispersing the metal Zn halide and the nitrogen-rich polymer in a solvent, carrying out an adsorption complexation reaction, and then evaporating the solvent to obtain a composite material of the metal Zn halide and the nitrogen-rich polymer; (2) The composite material of metal Zn halide and nitrogen-rich polymer is calcined, and after the calcination, metal Zn is immobilized on the nitrogen-rich carbon-based composite material.

7. The preparation method according to claim 6, characterized in that In step (1), the conditions for the adsorption complexation reaction are: temperature of 20-30°C and time of 3-5h.

8. The preparation method according to claim 6, characterized in that In step (2), the calcination treatment conditions are: the holding time is 1-3h.

Images