Preparation method and application of carbon-supported CeNCl catalyst

Abstract

The application discloses a preparation method of a carbon-loaded CeNCl catalyst and application thereof, and belongs to the field of catalysts. The preparation method comprises the following steps: mixing cerium chloride and chitosan, and performing ball milling treatment to obtain pretreated materials; and performing calcination treatment on the pretreated materials in an N2 atmosphere, and naturally cooling after the calcination treatment is completed to obtain the carbon-loaded CeNCl catalyst. The catalyst preparation process is simple, time-consuming is short, and mass production and industrial application can be realized. The catalyst after a catalytic reaction is easy to separate and recycle. The catalyst preparation raw materials are widely sourced and cheap. The catalyst has excellent catalytic performance and can obtain a yield close to 100%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalyst preparation, and particularly relates to a preparation method of a carbon-supported CeNCl catalyst and application thereof. BACKGROUND

[0002] Overuse of fossil fuels has led to record-breaking CO2 concentrations in the atmosphere, causing a serious environmental crisis. CO2 capture and conversion into high-value-added chemicals provides a promising approach to solving this problem. The cycloaddition reaction of CO2 with epoxides is a reaction with high atomic economy, which can produce cyclic carbonates that can be widely used as solvents, electrolytes, pharmaceutical intermediates and polymerization monomers in the chemical and materials industries. In addition, cyclic carbonates are also highly stable liquid compounds that ensure long-term CO2 sequestration.

[0003] Among various cyclic carbonates, styrene carbonate (SC) produced by the CO2 cycloaddition of styrene oxide (SO) has attracted widespread attention, with a market value of SC being about 120 times higher than that of SO. In the cycloaddition reaction of CO2 with epoxides, the high C=O bond energy of CO2 is as high as 805 kJ mol -1 , which leads to the difficulty in activation of CO2 in the reaction, so it is often necessary to add a catalyst to reduce the activation energy of the reaction.

[0004] The catalysts currently used include homogeneous catalysts and heterogeneous catalysts, among which the homogeneous catalysts mainly include ionic liquids, organic catalysts, etc., which have good catalytic performance, but have the problems of difficult separation and recovery; the heterogeneous catalysts include zeolites, metal-organic frameworks (MOFs), mesoporous oxides, porous polymers, etc., but most of them require high temperature and high pressure in the process of CO2 activation. Considering energy and catalyst manufacturing costs, it is very necessary to develop effective heterogeneous catalysts for reactions under mild conditions.

[0005] For example, a patent: a hydrotalcite supported doped gold catalyst for CO2 cycloaddition reaction and synthesis of bisphenol F and preparation method (CN201710769376.2), which discloses a preparation method of hydrotalcite supported doped gold catalyst and its application in CO2 cycloaddition reaction. First, AuPMe3Cl was prepared by multiple stirring, precipitation and filtration processes, then AuPMe3Cl and MgO, NaBF4, dodecanethiol, toluene were stirred together, washed after precipitation to obtain Au nanoparticles; finally, the obtained Au nanoparticles were mixed with hydrotalcite and toluene, stirred, centrifuged, washed and freeze-dried to obtain Au@Mg@HT. The disadvantages of this method are: three-step preparation of hydrotalcite supported doped gold catalyst, complex operation and long synthesis cycle; the addition of noble metal increases the cost of the catalyst, which is not conducive to large-scale industrial use. Patent: a polyionic liquid composite material and its preparation method and application (CN201810345759.1), which discloses a preparation method of polyionic liquid composite material and its application in CO2 cycloaddition reaction, preparation as follows: the carrier is ultrasonically dispersed in an organic solvent, silane coupling reagent is added and reacted for 12-48h to obtain product A; product A is cooled, centrifuged and washed, then solvent and organic amine are added and reacted for 12-48h to obtain product B; finally, product B is cooled and added with dihalogenated hydrocarbon and reacted for 12-48h to obtain product C, which is cooled, centrifuged, dried and ground to obtain the polyionic liquid composite material; the disadvantages of this method are: three-step preparation of polyionic liquid composite material, complex synthesis process, long time-consuming and not conducive to large-scale industrial use; the polyionic catalyst has the problem of difficult separation of catalyst and product. Patent: a pyridinium salt metal cobalt porphyrin and its preparation method (CN201811039465.2), which discloses a preparation method of pyridinium salt metal cobalt porphyrin and its application in CO2 cycloaddition reaction, preparation as follows: 5,10,15,20-tetra(4-(3-(4-(N-ethyl)pyridine bromide)pyrazolyl)phenyl)porphyrin is dissolved in water, then cobalt acetate is added and heated to reflux until the reaction is complete; then the solution is cooled to room temperature, excess NH4PF6 is added to the solution to completely precipitate the cobalt porphyrin, which is filtered, the solid is washed with anhydrous ether for several times and dried to obtain the crude product; the crude product is dissolved in acetone, excess tetrabutylammonium bromide is added to the solution to completely precipitate the cobalt porphyrin in the form of bromide salt, which is filtered, the solid is washed with acetone for several times and naturally dried to obtain the final metal cobalt porphyrin product; the disadvantages of this method are: the catalyst structure is relatively complex, the synthesis route is complex, the price of the complex monomer is high, and the organic ligand has certain toxicity. SUMMARY

[0006] This section is intended to introduce some aspects of one or more embodiments of the present application, which are described below in the detail section. This section is not intended to limit the application in any way, but to provide insight into various aspects of the application. Some of the concepts can be widely applicable to a variety of applications, and the claimed application can be adapted by one of ordinary skill in the art for use in a variety of applications.

[0007] In view of the above and / or other problems existing in the prior art, the present application is proposed.

[0008] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art, and provide a carbon-loaded CeNCl catalyst.

[0009] To solve the above technical problems, the present application provides the following technical solutions: A carbon-loaded CeNCl catalyst, the molar ratio of element Ce, element N and element Cl in the carbon-loaded CeNCl catalyst is 1:0.1-1:0.1-3.

[0010] As a preferred scheme of the carbon-loaded CeNCl catalyst according to the present application, the molar ratio of element Ce, element N and element Cl in the carbon-loaded CeNCl catalyst is 1:1:1.

[0011] Another purpose of the present application is to overcome the deficiencies in the prior art, and provide a preparation method of a carbon-loaded CeNCl catalyst.

[0012] To solve the above technical problems, the present application provides the following technical solutions: A preparation method of a carbon-loaded CeNCl catalyst, comprising,

[0013] Mixing cerium chloride and chitosan, ball milling treatment, to obtain a pretreated material;

[0014] The pretreated material is calcined in N2 atmosphere, and after calcination is completed, natural cooling is carried out to obtain a carbon-loaded CeNCl catalyst.

[0015] As a preferred scheme of the preparation method according to the present application, the mass ratio of cerium chloride to chitosan is 0.10-0.4:0.6-0.8.

[0016] As a preferred scheme of the preparation method according to the present application, the ball milling speed is 650-700 rpm, and the ball milling time is 5-15 min.

[0017] As a preferred scheme of the preparation method according to the present application, the calcination temperature is 600-900℃, the calcination time is 2-4h, and the heating rate is 3-10℃ / min.

[0018] Another object of the present application is to overcome the deficiencies in the prior art and provide an application of carbon-loaded CeNCl catalyst in the cycloaddition reaction of CO2 and epoxide to generate cyclic carbonate.

[0019] As a preferred scheme of the application, the epoxide and N,N-dimethylformamide are added to the reaction kettle, and the carbon-loaded CeNCl catalyst and tetrabutylammonium bromide are added.

[0020] After the reaction is completed, the catalyst is separated by centrifugation or filtration to obtain the product styrene carbonate.

[0021] As a preferred scheme of the application, the epoxide includes styrene oxide, epichlorohydrin, epoxy propane, epoxy cyclohexane, epoxy propyl phenyl ether, and 1,2-epoxy butane.

[0022] As a preferred scheme of the application, the reaction is completed under the following reaction conditions: CO2 initial pressure of 0.5-1.5 MPa, reaction temperature of 80-120℃, and reaction time of 6-36h.

[0023] As a preferred scheme of the application, the ratio of the epoxide, N,N-dimethylformamide, and carbon-loaded CeNCl catalyst is 1-2.5ml:3-7.5ml:0.02-0.05g, and the addition amount of tetrabutylammonium bromide is 0-5mol%.

[0024] The present application has the following advantages:

[0025] (1) The present application provides a preparation method of carbon-loaded CeNCl catalyst. Firstly, it solves the problems of difficult separation and recovery of homogeneous catalysts such as ionic liquid materials in CO2 cycloaddition reaction. Secondly, it uses anhydrous cerium chloride and chitosan as catalyst preparation raw materials, which are widely available and low in cost, solving the problems of expensive raw materials of some metal complex catalyst monomers and noble metal catalysts. Thirdly, it solves the problems of high toxicity of some catalysts or coordination monomers, complex catalyst synthesis route, and long time consumption. Finally, the catalyst preparation method in the present application is simple and fast, can realize large-scale synthesis, and has high potential industrial application value in the field of energy catalysis.

[0026] (2) Compared with the prior art, the carbon-loaded CeNCl catalyst proposed in the present application has a simple preparation method, a wide range of raw material sources, excellent catalytic activity, and robust tolerance, and can obtain a yield close to 100%. The catalyst can be used for 5 times of experiments and can still maintain a level close to the initial catalytic performance after 180 hours of catalysis. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings. Among them:

[0028] Figure 1 Preparation flow chart of carbon-supported CeNCl catalyst according to the present application;

[0029] Figure 2 X-ray diffraction pattern of carbon-supported CeNCl catalyst according to the present application;

[0030] Figure 3 Transmission electron microscopy image and element analysis image of carbon-supported CeNCl catalyst according to the present application;

[0031] Figure 4 Catalytic reaction yield result chart of the catalyst prepared according to the present application after 5 cycles of testing;

[0032] Figure 5 XRD spectrum of the catalyst obtained in Comparative Example 3 of the present application;

[0033] Figure 6 XRD spectrum of the catalyst obtained in Example 9 of the present application;

[0034] Figure 7 XRD spectrum of the catalyst obtained in Example 10 of the present application. DETAILED DESCRIPTION

[0035] In order to make the above objectives, features and advantages of the present application more apparent and comprehensible, the specific embodiments of the present application will be described in detail in conjunction with the description of the embodiments.

[0036] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0037] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. In this specification, "in one embodiment" appearing in different places does not mean the same embodiment, nor is it an independent or alternative embodiment that excludes other embodiments.

[0038] Example 1

[0039] Synthesis of CeNCl / C catalyst:

[0040] 0.15 g of cerium chloride and 0.6 g of chitosan were placed in a ball mill tank, 30 g of agate grinding balls were taken, the rotation speed of the ball mill was set to 650 rpm, and the ball milling time was 5 min;

[0041] After ball milling, the mixture was placed in a ceramic boat and calcined in a N2 atmosphere, the heating rate was 5℃ / min, the calcination temperature was 800℃, the calcination time was 2 h, and after the end of the calcination, the sample was naturally cooled to room temperature to obtain the CeNCl / C catalyst.

[0042] The synthesis route thereof is shown in Figure 1 , the X-ray diffraction characterization is shown in Figure 2 , the transmission electron microscopy and elemental analysis are shown in Figure 3 , wherein, Figure 2 The XRD pattern in Figure 3 shows characteristic peaks attributed to CeNCl, indicating the successful synthesis of CeNCl / C, The transmission electron microscopy and elemental analysis of the catalyst of

[0043] indicate the uniform distribution of Ce, N, and Cl elements in CeNCl.

[0044] The CeNCl / C catalyst is used to catalyze the cycloaddition reaction of CO2 and oxidized styrene:

[0045] 2.5 ml of oxidized styrene and 3 ml of N,N-dimethylformamide were added to the reaction kettle, 0.05 g of CeNCl / C catalyst prepared in Example 1 and 5 mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction conditions were as follows: CO2 initial pressure 1.0 MPa, reaction temperature 100℃, and reaction time 36 h;

[0046] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0047] The product was analyzed by gas chromatography-mass spectrometry, and the yield of the product styrene carbonate was 99%.

[0048] Example 3

[0049] The CeNCl / C catalyst is used to catalyze the cycloaddition reaction of CO2 and epichlorohydrin:

[0050] The oxidized styrene in Example 2 was replaced by epichlorohydrin, and the reaction conditions were as follows: CO2 initial pressure 1.0 MPa, reaction temperature 100℃, and reaction time 36 h;

[0051] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0052] The product was analyzed by gas chromatography-mass spectrometry, and the yield of the product was 98.3%.

[0053] Example 4

[0054] CeNCI / C catalyst was used to catalyze the cycloaddition reaction of CO2 and propylene oxide:

[0055] The styrene oxide in Example 2 was replaced by propylene oxide, and the reaction conditions were: CO2 initial pressure 1.0 MPa, reaction temperature 100 °C, and reaction time 36 h;

[0056] After the reaction was completed, the catalyst was separated by centrifugation or filtration. The product was analyzed by GC-MS, and the product yield was 93.6%.

[0057] Example 5

[0058] CeNCI / C catalyst was used to catalyze the cycloaddition reaction of CO2 and cyclohexene oxide:

[0059] The styrene oxide in Example 2 was replaced by cyclohexene oxide, and the reaction conditions were: CO2 initial pressure 1.0 MPa, reaction temperature 100 °C, and reaction time 36 h;

[0060] After the reaction was completed, the catalyst was separated by centrifugation or filtration. The product was analyzed by GC-MS, and the product yield was 81.2%.

[0061] Example 6

[0062] CeNCI / C catalyst was used to catalyze the cycloaddition reaction of CO2 and propyl phenyl ether oxide:

[0063] The styrene oxide in Example 2 was replaced by propyl phenyl ether oxide, and the reaction conditions were: CO2 initial pressure 1.0 MPa, reaction temperature 100 °C, and reaction time 36 h;

[0064] After the reaction was completed, the catalyst was separated by centrifugation or filtration. The product was analyzed by GC-MS, and the product yield was 53.9%.

[0065] Example 7

[0066] CeNCI / C catalyst was used to catalyze the cycloaddition reaction of CO2 and 1,2-butene oxide:

[0067] The styrene oxide in Example 2 was replaced by 1,2-butene oxide, and the reaction conditions were: CO2 initial pressure 1.0 MPa, reaction temperature 100 °C, and reaction time 36 h;

[0068] After the reaction was completed, the catalyst was separated by centrifugation or filtration. The product was analyzed by GC-MS, and the product yield was 90.8%.

[0069] Example 8

[0070] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added into a reaction kettle, 0.05g of CeNCI / C catalyst was added, and the reaction conditions were as follows: initial pressure of CO2 1.0MPa, reaction temperature 100℃, and reaction time 36h;

[0071] After the reaction was completed, the catalyst was separated by centrifugation or filtration. The product was analyzed by GC-MS, and the yield of styrene carbonate was 77.4%.

[0072] The reaction conditions and results of the CO2 cycloaddition reactions of Examples 2-8 are shown in Table 1.

[0073] Table 1

[0074]

[0075]

[0076] Example 9

[0077] Temperature adjustment of CeNCI / C catalyst synthesis:

[0078] 0.15g of cerium chloride and 0.6g of chitosan were placed in a ball mill jar, 30g of marbled grinding balls were taken, the rotation speed of the ball mill was set to 650rpm, and the ball milling time was 5min;

[0079] After ball milling, the mixture was placed in a ceramic boat and calcined in a N2 atmosphere, the heating rate was 5℃ / min, the calcination temperature was 600℃, 700℃, 800℃, and 900℃ respectively, the calcination time was 2h, and after the end of calcination, it was naturally cooled to room temperature to obtain the CeNCI / C catalyst.

[0080] The XRD spectrum of the obtained catalyst is shown in Figure 6 The results show that CeNCI with increasing crystallinity can be generated at 600℃, 700℃, 800℃, and 900℃.

[0081] Example 10

[0082] Ce content adjustment of CeNCI / C catalyst:

[0083] 0.1g, 0.15g, 0.2g, 0.3g, and 0.4g of cerium chloride and 0.6g of chitosan were sequentially placed in a ball mill jar, 30g of marbled grinding balls were taken, the rotation speed of the ball mill was set to 650rpm, and the ball milling time was 5min;

[0084] After ball milling, the mixture was placed in a ceramic boat and calcined in N2atmosphere, the heating rate was 5℃ / min, the calcination temperature was 800℃, the calcination time was 2h, and then naturally cooled to room temperature to obtain the CeNCl / C catalyst.

[0085] The XRD spectrum of the obtained catalyst is shown in Figure 7 The results show that the CeNCl / C catalyst with different loadings can be generated when 0.1g, 0.15g, 0.2g, 0.3g, 0.4g of cerium chloride and 0.6g of chitosan are mixed.

[0086] Example 11

[0087] 0.1g of cerium chloride and 0.6g of chitosan were placed in a ball mill tank, 30g of agate grinding balls were taken, the rotation speed of the ball mill was set to 650rpm, and the ball milling time was 5min;

[0088] After ball milling, the mixture was placed in a ceramic boat and calcined in N2atmosphere, the heating rate was 5℃ / min, the calcination temperature was 800℃, the calcination time was 2h, and then naturally cooled to room temperature to obtain the CeNCl / C-0.1 catalyst.

[0089] 2.5ml of styrene oxide and 3ml of N,N-dimethylformamide were added to the reaction kettle, 0.05g of CeNCl / C-0.1 catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction conditions were as follows: CO2initial pressure 1.0MPa, reaction temperature 100℃, and reaction time 36h;

[0090] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0091] The product was analyzed by GC-MS, and the yield of styrene carbonate was 92.6%.

[0092] Example 12

[0093] 0.2g of cerium chloride and 0.6g of chitosan were placed in a ball mill tank, 30g of agate grinding balls were taken, the rotation speed of the ball mill was set to 650rpm, and the ball milling time was 5min;

[0094] After ball milling, the mixture was placed in a ceramic boat and calcined in N2atmosphere, the heating rate was 5℃ / min, the calcination temperature was 800℃, the calcination time was 2h, and then naturally cooled to room temperature to obtain the CeNCl / C-0.2 catalyst.

[0095] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added to the reaction kettle, 0.05g of CeNCl / C-700 catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction conditions were: CO2 initial pressure 1.0MPa, reaction temperature 100℃, reaction time 36h;

[0096] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0097] The product was analyzed by gas chromatography-mass spectrometry, and the yield of the product styrene carbonate was 51.6%.

[0098] Example 13

[0099] 0.15g of cerium chloride and 0.6g of chitosan were placed in a ball mill tank, 30g of agate grinding balls were taken, the rotation speed of the ball mill was set to 650rpm, and the ball milling time was 5min;

[0100] After ball milling, the mixture was placed in a ceramic boat and calcined in a N2 atmosphere, the heating rate was 5℃ / min, the calcination temperature was 700℃, the calcination time was 2h, and after the end of the calcination, the sample was naturally cooled to room temperature to obtain the CeNCl / C-700 catalyst.

[0101] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added to the reaction kettle, 0.05g of CeNCl / C-700 catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction conditions were: CO2 initial pressure 1.0MPa, reaction temperature 100℃, reaction time 36h;

[0102] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0103] The product was analyzed by gas chromatography-mass spectrometry, and the yield of the product styrene carbonate was 51.6%.

[0104] Example 14

[0105] 0.15g of cerium chloride and 0.6g of chitosan were placed in a ball mill tank, 30g of agate grinding balls were taken, the rotation speed of the ball mill was set to 650rpm, and the ball milling time was 5min;

[0106] After ball milling, the mixture was placed in a ceramic boat and calcined in a N2 atmosphere, the heating rate was 5℃ / min, the calcination temperature was 900℃, the calcination time was 2h, and after the end of the calcination, the sample was naturally cooled to room temperature to obtain the CeNCl / C-900 catalyst.

[0107] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added into the reactor, 0.05g of CeNCI / C-900 catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction was carried out under the following conditions: CO2 initial pressure 1.0MPa, reaction temperature 100℃, and reaction time 36h;

[0108] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0109] The product was analyzed by GC-MS, and the yield of styrene carbonate was 79.1%.

[0110] Example 15

[0111] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added into the reactor, 0.05g of CeNCI / C catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction was carried out under the following conditions: CO2 initial pressure 0.5MPa, reaction temperature 100℃, and reaction time 36h;

[0112] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0113] The product was analyzed by GC-MS, and the yield of styrene carbonate was 83.0%.

[0114] Example 16

[0115] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added into the reactor, 0.05g of CeNCI / C catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction was carried out under the following conditions: CO2 initial pressure 1.5MPa, reaction temperature 100℃, and reaction time 36h;

[0116] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0117] The product was analyzed by GC-MS, and the yield of styrene carbonate was 85.1%.

[0118] Example 17

[0119] 2.5ml of oxidized styrene and 3ml of N,N-dimethylformamide were added into the reactor, 0.05g of CeNCI / C catalyst and 5mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction was carried out under the following conditions: CO2 initial pressure 1.2MPa, reaction temperature 80℃, and reaction time 36h;

[0120] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0121] The product was analyzed by GC-MS, and the yield of styrene carbonate was 60.3%.

[0122] Example 18

[0123] 2.5 ml of oxidized styrene and 3 ml of N,N-dimethylformamide were added into a reaction kettle, 0.05 g of CeNCI / C catalyst and 5 mol% of tetrabutylammonium bromide (TBAB) were added, and the reaction conditions were as follows: CO2 initial pressure 1.0 MPa, reaction temperature 120°C, and reaction time 36 h.

[0124] After the reaction was completed, the catalyst was separated by centrifugation or filtration.

[0125] The product was analyzed by GC-MS, and the yield of styrene carbonate was 90.9%.

[0126] The reaction conditions and results of the CO2 cycloaddition reactions of Examples 11-18 are shown in Table 2.

[0127] Table 2

[0128]

[0129] Example 19

[0130] Catalyst recycling test:

[0131] The catalyst recovered from Example 2 was subjected to a recycling test, and the reaction conditions were as follows: CO2 initial pressure 1.0 MPa, reaction temperature 100°C, and reaction time 36 h. After the reaction was completed, the catalyst was separated by centrifugation or filtration, and the recycling was performed for 4 times. The yield of styrene carbonate in the total of 5 recycling reactions was as follows: Figure 4 It can be seen that the catalyst has a robust tolerance.

[0132] Comparative Example 1

[0133] 2.5 ml of oxidized styrene and 3 ml of N,N-dimethylformamide were added into a reaction kettle, 5 mol% of tetrabutylammonium bromide (TBAB) was added, and the reaction conditions were as follows: CO2 initial pressure 1.0 MPa, reaction temperature 100°C, and reaction time 36 h.

[0134] After the reaction was completed, the catalyst was separated by centrifugation or filtration. The product was analyzed by GC-MS, and the yield of styrene carbonate was 30.5%.

[0135] Comparative Example 2

[0136] 2.5 ml of oxidized styrene and 3 ml of N, N-dimethylformamide were added into the reaction kettle without catalyst, and the reaction conditions were as follows: initial pressure of CO2 1.0 MPa, reaction temperature 100 ℃, and reaction time 36 h; after the reaction, the catalyst was separated by centrifugation or filtration.

[0137] The product was analyzed by GC-MS, and the yield of styrene carbonate was 10.7%.

[0138] Comparative Example 3

[0139] Synthesis of CeNCl / C catalyst by changing nitrogen source:

[0140] 0.15 g of cerium chloride and 0.6 g of dicyandiamide were placed in a ball mill jar, 30 g of agate grinding balls were taken, the rotation speed of the ball mill was set to 650 rpm, and the ball milling time was 5 min.

[0141] After ball milling, the mixture was placed in a ceramic boat and calcined in a N2 atmosphere, the heating rate was 5 ℃ / min, the calcination temperature was 800 ℃, the calcination time was 2 h, and after the end of calcination, the sample was naturally cooled to room temperature to obtain the CeNCl / C catalyst.

[0142] The XRD spectrum of the obtained catalyst is shown in Figure 5 The results show that dicyandiamide cannot generate CeNCl as a nitrogen source.

[0143] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the present application.

Claims

1. The application of a carbon-supported CeNCl catalyst in the cycloaddition reaction of CO2 with epoxides to form cyclic carbonates, characterized in that: The molar ratio of Ce, N, and Cl in the carbon-supported CeNCl catalyst is 1:0.1~1:0.1~3; The preparation method of the carbon-supported CeNCl catalyst includes mixing cerium chloride and chitosan, ball milling, and obtaining a pretreated material, wherein the mass ratio of cerium chloride to chitosan is 0.1~0.4:0.6~0.8; The pretreated material was calcined in an N2 atmosphere and then naturally cooled after calcination to obtain a carbon-supported CeNCl catalyst.

2. The application as described in claim 1, characterized in that: The molar ratio of Ce, N, and Cl in the carbon-supported CeNCl catalyst is 1:1:

1.

3. The application as described in claim 1, characterized in that: The ball milling process involves a ball milling speed of 650-700 rpm and a ball milling time of 5-15 min.

4. The application as described in claim 1, characterized in that: The calcination treatment includes a calcination temperature of 600~900℃, a calcination time of 2~4h, and a heating rate of 3~10℃ / min.

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