A ternary high-copper Cu x Fe y Ce 0.5 Metal oxide catalysts, methods for their preparation and use

Abstract

The application discloses a ternary high-copper Cu x Fe y Ce 0.5 Metal oxide catalyst, a preparation method thereof and application of the metal oxide catalyst in catalyzing reaction of aniline and carbon dioxide to synthesize N,N'-diphenylurea. The application adopts a one-step coprecipitation method, uses copper nitrate trihydrate, iron nitrate nonahydrate and cerium nitrate hexahydrate as raw materials, and in the presence of a sodium carbonate precipitant, adjusts the pH value through sodium hydroxide to prepare a ternary high-copper Cu x Fe y Ce 0.5 Metal oxide, the specific surface area of which is 36-77 m 2 / g, the copper-iron ratio is 4:1-10:1, and the crystallinity is 70-100%. The synthesis method is convenient to operate and has good reproducibility. Compared with existing catalysts, the ternary high-copper Cu x Fe y Ce 0.5 Metal oxide prepared by the application has higher catalytic activity, good reusability in the reaction process of catalyzing reaction of aniline and carbon dioxide to synthesize N,N'-diphenylurea, and the selectivity rate of the synthesized N,N'-diphenylurea is as high as 99.9%, and the aniline conversion rate is as high as 32.9%, so the application has a good application prospect in the field of catalytic synthesis.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of industrial catalytic synthesis, and particularly relates to a ternary high-copper Cu x Fe y Ce 0.5 Metal oxide catalyst, its preparation method and application. BACKGROUND

[0002] N,N'-diphenylurea is an important chemical raw material and organic synthesis intermediate, which is widely used in the fields of organic synthesis and material science. For example, N,N'-diphenylurea can be used for synthesizing a series of important compounds such as carbamates and sulfonamides, can be used for synthesizing new plant growth regulators, promoting the synthesis of chlorophyll, inhibiting the activity of oxidase, and can be applied to high-end automobiles, ships, aviation and other fields.

[0003] Currently, the synthesis of N,N'-diphenylurea mainly adopts the phosgene method, which requires the use of toxic phosgene and the generated by-product hydrochloric acid can seriously corrode the equipment (Li Y Q, Huang K L, Xie Y S, Li K X, Wu R. Research progress of clean synthesis process of diphenylurea. Popular Science and Technology, 2015, 17, 32-36). Therefore, the technology for synthesizing N,N'-diphenylurea by non-phosgene method has emerged as the times require. Among them, the one-step reaction of carbon dioxide and aniline to synthesize N,N'-diphenylurea is considered as the most efficient and promising synthesis method. It has significant advantages such as low raw material cost, resource utilization of greenhouse gas CO2 molecules, simple process, and environmental friendliness. Existing reports show that the activation of CO2 molecules is the key to the technology for preparing N,N'-diphenylurea. For example, Zhang L L et al. used CO2 and aniline as raw materials, supported CuFe / ZrO2 as catalyst, acetonitrile as solvent, CO2 initial pressure of 1 MPa, and reacted at 160 ℃ for 7 h. The conversion rate of aniline was 5.5% and the selectivity of N,N'-diphenylurea was 96.9%, but there were problems such as low conversion rate of aniline and the product selectivity could not be further improved (Zhang L L, An H L, Zhao X Q, Wang Y J. Cu-Fe / ZrO2 catalyzed synthesis of diphenylurea from aniline and CO2. Acta Petrolei Sinica (Petroleum Processing), 2014, 30, 817-822). Yao S J et al. used acidic ionic liquid BmimCl-AlCl3 as catalyst, CO2 and aniline as raw materials, and reacted at 160 ℃ for 7 h under an initial pressure of 1 MPa. The conversion rate of aniline was 18.1% and the selectivity of N,N'-diphenylurea was 98.9%. However, since the ionic liquid homogeneous catalyst was used, there were problems such as high cost, difficulty in recovery, and low conversion rate of aniline, which did not meet the requirements of sustainable chemistry and green chemistry (Yao S J, Zhao X Q, An H L, Wang Y J. Acidic ionic liquid catalyzed synthesis of diphenylurea from aniline and carbon dioxide. Chemical Engineering, 2012, 63, 812-818). Therefore, it is of great significance to develop a non-homogeneous catalyst with high activity, low price, good thermal stability, and recyclable use for efficiently catalyzing the synthesis of N,N'-diphenylurea from aniline and CO2.

[0004] Metal oxides have high catalytic efficiency, good stability, low cost, and strong renewability, making them widely used as a class of highly active heterogeneous catalysts in various catalytic fields such as petroleum and chemical industry, fine chemical industry, etc. Currently, although there are more and more simple applications of CuFeCe metal oxide composites in various catalytic processes, the formation of catalytically active centers still needs further understanding. The strong interaction between metal and oxygen atoms improves the excellent catalytic activity of ternary CuFeCe metal oxides, thereby significantly enhancing the texture properties and oxygen storage-release capacity. Among them, the formation of stronger interaction forces between Cu and other metal oxides can promote the formation of oxygen vacancies, thereby effectively improving the activity of metal oxide catalysts. Gianluca Landi et al. loaded copper and iron on a commercial ceria carrier by impregnation method to prepare Cu-Fe / CeO2 metal oxide catalyst, which was used for water gas shift reaction. Under the condition of Fe / Cu mass ratio of 1:4, compared with the catalyst containing two metal oxide components, the ternary composite metal oxide catalyst showed more excellent redox activity, selectivity and higher stability. The reason is that the strong interaction between Cu and Fe and between metal and carrier is beneficial to the reaction (G. Landi, G. Sorbino, F. Migliardini, G. Ruoppolo, A. Di Benedetto. Enhanced activity of bimetallic Fe-Cu catalysts supported on ceria toward water gas shift reaction: synergistic effect. Frontiers of Chemical Science and Engineering, 2023, 17, 1962-1972). Liu Hao et al. prepared three-dimensional ordered macroporous Ce 0.7 Fe 0.2 Cu 0.1 O2 catalyst by using polymethyl methacrylate and triblock copolymer P123 as template agents, and corresponding nitrate as metal precursor through one-step method. It was used for CO selective catalytic reduction of NO reaction, and showed excellent catalytic activity in the wide working temperature range of 150-700 ℃. Since CeO2 has low activity at low temperature, the ternary metal oxide catalyst composed of Cu and Fe can significantly improve its catalytic activity. In addition, the presence of more oxygen vacancies in the metal oxide catalyst is beneficial to the dissociation of the reactant NO, and the surface oxygen species is easy to be captured by CO to form Cu + -CO, and adsorbed NO xThe active species reacts, which has higher catalytic performance (H. Liu, Q. Liang, J. Liu, X. Liu, D. Li, S. Xie, L. Jin, L. Dong, B. Li, Y. Yao. Promotional mechanism of activity via three-dimensional ordered macroporous Cu-doped Ce-Fe mixed oxides for the CO-SCR reaction. Environmental Science-nano, 2020, 7, 3136-3154).

[0005] However, so far, there is no relevant literature report on the ternary high-copper CuFeCe metal oxide catalyst prepared by one-step coprecipitation method and applied to catalyze the reaction of aniline and CO2 to synthesize N,N'-diphenylurea.

[0006] Therefore, it is of great scientific significance and application value to develop a ternary high-copper CuFeCe metal oxide catalyst with high activity, good thermal stability and recyclability, and apply it to efficiently catalyze the reaction of CO2 and aniline to synthesize N,N'-diphenylurea. SUMMARY

[0007] In view of the above and / or 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 to provide a ternary high-copper metal oxide catalyst and a preparation method and application thereof.

[0009] One of the purposes of the present application is to provide a ternary high-copper Cu x Fe y Ce 0.5 Metal oxide catalyst, characterized in that: the structure of the ternary high-copper metal oxide is Cu x Fe y Ce 0.5 , wherein x and y represent the amount of substance of Cu, Fe, respectively, x:y=4:1~10:1;

[0010] The ternary high-copper Cu x Fe y Ce 0.5 Metal oxide catalyst has the characteristic X-ray powder diffraction pattern (PXRD) as shown in Table 1:

[0011] ,

[0012] wherein the X-ray powder diffraction pattern is based on a relative intensity scale, wherein the strongest line in the X-ray powder diffraction pattern is assigned a value of 100, and wherein the corresponding relative intensities are: w represents weak, i.e. ≤ 20; m represents medium, i.e. > 20 to ≤ 40; s represents strong, i.e. > 40 to ≤ 60.

[0013] as a ternary high-copper Cu x Fe y Ce 0.5 A preferred embodiment of the metal oxide catalyst, wherein: the ternary high-copper Cu x Fe y Ce 0.5 The specific surface area of the metal oxide catalyst is 36-77 m 2 / g, and the crystallinity is 70%-100%.

[0014] The second object of the present application is to provide the ternary high-copper Cu x Fe y Ce 0.5 A preparation method of the metal oxide catalyst, comprising,

[0015] 1) preparing a mixed solution of copper salt, iron salt, cerium nitrate hexahydrate and deionized water;

[0016] 2) adding the mixed salt solution and the aqueous NaOH solution dropwise into the aqueous Na2CO3 solution, adjusting the pH, and stirring at constant temperature to obtain a coprecipitate;

[0017] 3) washing the obtained coprecipitate with deionized water until neutral, drying, and calcining to obtain the ternary high-copper Cu x Fe y Ce 0.5 metal oxide catalyst.

[0018] As a preferred embodiment of the preparation method, in step 1), the copper salt is one or a mixture of copper nitrate trihydrate, copper acetate monohydrate, copper sulfate pentahydrate, and copper chloride dihydrate, and the amount of copper salt is 2.36-3.34 g per 1 g of cerium nitrate hexahydrate; the iron salt is one or a mixture of iron nitrate nonahydrate, iron acetate, iron sulfate, and iron chloride hexahydrate, and the amount of iron salt is 0.40-0.93 g per 1 g of cerium nitrate hexahydrate.

[0019] As a preferred embodiment of the preparation method, in step 2), the concentration of the aqueous NaOH solution is 1.5 M-3.0 M, and the concentration of the aqueous Na2CO3 solution is 0.5 M-3.0 M.

[0020] As a preferred scheme of the preparation method, in step 2), the pH is adjusted to 10-13, the stirring temperature is 50-100 DEG C, and the stirring time is 4-9 h.

[0021] As a preferred scheme of the preparation method, in step 3), the calcination is carried out at 400-500 DEG C for 5-7 h.

[0022] The third object of the present application is to provide a ternary high-copper Cu x Fe y Ce 0.5 The application of the metal oxide catalyst is characterized in that the ternary high-copper Cu x Fe y Ce 0.5 The metal oxide catalyst is used for catalyzing the reaction of aniline and CO2 to prepare N,N'-diphenylurea, wherein the preparation method is that aniline, a solvent and Cu x Fe y Ce 0.5 The metal oxide catalyst is mixed, CO2 with a certain pressure is filled, and then the reaction is carried out at 100-200 DEG C for 3-10 h, so that N,N'-diphenylurea is obtained.

[0023] As a preferred scheme of the application, the solvent is one or more of acetonitrile, methanol, deionized water and anhydrous ethanol; the volume ratio of aniline to the solvent is 3:1-1:9, 0.08-0.6 g of the catalyst corresponds to 1 ml of aniline; the amount of the catalyst is 0.4-1.0 g; and the certain pressure is 0.5-3.0 MPa.

[0024] As a preferred scheme of the application, the N,N'-diphenylurea can be applied to the fields of chemical industry, organic synthesis and material science.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The ternary high-copper Cu x Fe y Ce 0.5 Metal oxide catalyst is prepared by one-step coprecipitation, and has the advantages of high activity, good stability and easy separation; compared with the hydrothermal method and the impregnation method, the Cu x Fe y Ce 0.5 Metal oxide catalyst synthesized by the coprecipitation method not only prevents the aggregation of particles and ensures the uniform dispersion of Cu, Fe and Ce active species, but also synthesizes the ternary high-copper Cu x Fe y Ce 0.5The metal oxide catalyst has good crystallinity, and reduces loss of active metal.

[0027] (2) The ternary high-copper Cu x Fe y Ce 0.5 The metal oxide catalyst contains rich active metal sites, which is beneficial to adsorption and activation of reactants. Meanwhile, the good crystal structure of the catalyst is also beneficial to diffusion of reactant and product molecules. The active sites of the metal Cu can make the lone pair electrons on the nitrogen atom in the aniline molecule and the partial positive charge on the carbon atom in the CO2 molecule undergo nucleophilic reaction to form an intermediate, and then one molecule of water is removed, and then amine saltization reaction occurs to generate the product N,N'-diphenylurea. The strong synergistic catalysis significantly improves the catalytic performance of the ternary high-copper Cu x Fe y Ce 0.5 Metal oxidation catalytic activity;

[0028] (3) The experimental results show that the Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst has high catalytic performance, and the selectivity of the amine saltization reaction of aniline and CO2 to generate N,N'-diphenylurea can be as high as 99.9%, and the aniline conversion rate can be as high as 32.9%. The metal oxide catalyst can be applied in the fields of organic synthesis and material science, and has certain industrial utilization value. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. The drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0030] Figure 1 Cu3Fe 0.5 Ce 0.5 X-ray powder diffraction (PXRD) spectrum of the metal oxide catalyst.

[0031] Figure 2 Cu3Fe 0.5 Ce 0.5 Scanning electron microscope (SEM) schematic diagram of the metal oxide catalyst.

[0032] Figure 3 Cu3Fe 0.5 Ce 0.5Transmission electron microscopy (TEM) schematic diagram of metal oxide catalyst.

[0033] Figure 4 Cu3Fe prepared for the present embodiment 1 0.5 Ce 0.5 N2 adsorption-desorption curve of metal oxide catalyst.

[0034] Figure 5 Cu3Fe prepared for the present embodiment 1 0.5 Ce 0.5 Performance results of metal oxide catalysts in the reaction of aniline and CO2.

[0035] Figure 6 Cu3Fe prepared for the present embodiment 1 0.5 Ce 0.5 Catalytic effect diagram of metal oxide catalysts after five cycles. DETAILED DESCRIPTION

[0036] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the embodiments of the present application.

[0037] This section is intended to provide a summary of some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the abstract and title of the present application in order to avoid obscuring the purpose of this section, the abstract and the title of the present application, and such simplifications or omissions are not to be construed as limiting the scope of the present application.

[0038] 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 scope of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0039] 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 one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is separate or alternative to other embodiments.

[0040] The specifications of the chemical reagents used in the experiments of the present application and other information are shown in Table 2.

[0041]

[0042] Embodiment 1

[0043] Mix 3.34 g of copper nitrate trihydrate, 0.93 g of ferric nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water thoroughly and put them into a burette. Put the prepared 2 M NaOH aqueous solution into another burette.

[0044] Add 1.0 M Na2CO3 aqueous solution to a four-necked flask, insert a pH meter below the liquid surface, and add mixed salt solution and NaOH aqueous solution dropwise at a certain temperature until the pH reaches 12. Stir at 80 °C for 6 h.

[0045] The resulting coprecipitate was washed with deionized water until neutral, dried, and calcined at 450 °C for 6 h to obtain the ternary high-copper Cu3Fe. 0.5 Ce 0.5 Metal oxide catalysts.

[0046] The product weighed 5.7g, with a Cu content of 44.1 wt%, an Fe content of 7.5 wt%, a Ce content of 18.2 wt%, and a specific surface area of ​​77 m². 2 / g, crystallinity is 100%.

[0047] The models and other information of the instruments and equipment used in the experiments of this invention are shown in Table 3.

[0048]

[0049] Cu3Fe was analyzed using a Bruker D / max 2500 PC powder X-ray diffractometer (PXRD, Cu Kα radiation, λ=0.154 nm, scanning range 2θ 5°~50°). 0.5 Ce 0.5 Crystal structure and phases of metal oxides. Analysis results are as follows: Figure 1 As shown, 28.5°, 33.0°, 47.5°, 56.3°, 59.1°, and 69.4° are characteristic diffraction peaks of CeO2, 35.6° and 38.8° correspond to characteristic diffraction peaks of CuO, and 35.5°, 57.4°, 62.3°, and 63.9° correspond to characteristic diffraction peaks of Fe2O3, indicating the successful preparation of the catalyst. Furthermore, judging from the peak intensities, Cu3Fe... 0.5 Ce 0.5 The metal oxide peaks are strong and sharp, indicating that Cu3Fe 0.5 Ce 0.5 The good crystallinity of the metal oxide ensures its efficient catalytic reaction between aniline and CO2.

[0050] Cu3Fe was analyzed using a combination of TESCAN field emission scanning electron microscopy and FEI Talos F200X transmission electron microscopy. 0.5 Ce0.5 Morphology and crystal structure of metal oxide. As shown in the SEM image, it can be seen that Cu3Fe Figure 2 SEM image, it can be seen that Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst has a uniform size, a coral shape with a length of about 500 nm and a width of about 250 nm, and further from the SEM & EDS image, it can be seen that the metal elements Cu, Fe and Ce in the catalyst are in a highly dispersed state. As shown in the TEM result image, the metal oxide catalyst has good crystallinity, no other impurity amorphous phase is generated, and the morphology and structure are relatively regular. The independent active sites in the catalyst are beneficial to mass transfer, thereby effectively promoting the reaction activity of aniline and CO2. Figure 3

[0051] The Cu3Fe 0.5 Ce 0.5 Specific surface area, N2 adsorption-desorption curve and pore size distribution of the metal oxide material. The specific surface area is determined by the BET method, and the pore size distribution is determined by the BJH method. Before determination, the sample is dried at 120 ℃ for 2 h, and then placed in a vacuum environment at 150 ℃ for 12 h. As shown in the determination result, Figure 4 the N2 adsorption-desorption isotherm has a hysteresis loop at a relative pressure P / P0=0.5~1.0, which is caused by the capillary condensation phenomenon of N2 in the pores of the ternary high-copper-containing metal oxide, further indicating that the Cu3Fe 0.5 Ce 0.5 The metal oxide contains a mesoporous structure. From the pore size distribution curve, it can be seen that the Cu3Fe 0.5 Ce 0.5 The pore size of the metal oxide is mainly distributed at 4 nm and 7 nm, and the pore size distribution is uniform. Example 2

[0052] After mixing 2.76 g of copper acetate monohydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water uniformly, they are loaded into a burette, and a prepared 2 M NaOH aqueous solution is loaded into another burette;

[0053] 1 M Na2CO3 aqueous solution is added into a four-necked flask, a pH meter is inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution are added dropwise at a certain temperature until the pH is 12, and then stirred at 80 ℃ for 6 h;

[0054] The obtained coprecipitate is washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and a ternary high-copper-containing Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst. ​

[0055] The product quality was measured as 5.0 g, the metal Cu content was 40.1 wt%, the metal Fe content was 5.1 wt%, the metal Ce content was 14.3 wt%, the specific surface area was 56 m 2 / g, and the crystallinity was 91%. Example 3

[0056] 2.45 g of copper sulfate pentahydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and loaded into a burette, and 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0057] 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 12 at a certain temperature, and stirred at 80 ℃ for 6 h;

[0058] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.55 metal oxide catalyst.

[0059] The product quality was measured as 4.7 g, the metal Cu content was 39.9 wt%, the metal Fe content was 4.5 wt%, the metal Ce content was 12.2 wt%, the specific surface area was 64 m 2 / g, and the crystallinity was 88%. Example 4

[0060] 2.36 g of copper chloride dihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and loaded into a burette, and 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0061] 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 12 at a certain temperature, and stirred at 80 ℃ for 6 h;

[0062] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst.

[0063] The product quality was measured as 5.1 g, the metal Cu content was 38.6 wt%, the metal Fe content was 6.5 wt%, the metal Ce content was 16.2 wt%, the specific surface area was 72 m 2 / g, and the crystallinity was 90%. Example 5

[0064] 3.34 g of copper nitrate trihydrate, 0.40 g of iron acetate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and loaded into a burette, and 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0065] 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to pH 12 at a certain temperature, and stirred at 80°C for 6 h;

[0066] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450°C for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0067] The product quality was measured to be 5.4 g, the metal Cu content was 33.1 wt%, the metal Fe content was 6.1 wt%, the metal Ce content was 17.2 wt%, the specific surface area was 59 m 2 / g, and the crystallinity was 78%. Example 6

[0068] 3.34 g of copper nitrate trihydrate, 0.92 g of iron sulfate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and loaded into a burette, and 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0069] 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to pH 12 at a certain temperature, and stirred at 80°C for 6 h;

[0070] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450°C for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0071] The product quality was measured to be 5.1 g, the metal Cu content was 41.1 wt%, the metal Fe content was 6.66 wt%, the metal Ce content was 15.2 wt%, the specific surface area was 65 m 2 / g, and the crystallinity was 84%. Example 7

[0072] A mixture of 3.34 g of copper nitrate trihydrate, 0.62 g of iron chloride hexahydrate, 1 g of cerium nitrate hexahydrate and deionized water was prepared and loaded into a burette, and a 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0073] A 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise at a certain temperature until the pH was 12, and the mixture was stirred at 80°C for 6 h;

[0074] The obtained coprecipitate was washed to neutral with deionized water, dried, and calcined at 450°C for 6 h to obtain a ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0075] The product mass was measured to be 5.5 g, the metal Cu content was 40.1 wt%, the metal Fe content was 7.2 wt%, the metal Ce content was 17.8 wt%, the specific surface area was 67 m 2 / g, and the crystallinity was 75%. Example 8

[0076] A mixture of 2.23 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water was prepared and loaded into a burette, and a 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0077] A 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise at a certain temperature until the pH was 12, and the mixture was stirred at 80°C for 6 h;

[0078] The obtained coprecipitate was washed to neutral with deionized water, dried, and calcined at 450°C for 6 h to obtain a ternary high-copper Cu2Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0079] The product mass was measured to be 4.7 g, the metal Cu content was 24.1 wt%, the metal Fe content was 6.5 wt%, the metal Ce content was 15.2 wt%, the specific surface area was 66 m 2 / g, and the crystallinity was 88%. Example 9

[0080] A mixture of 4.45 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water was prepared and loaded into a burette, and a 2 M NaOH aqueous solution was prepared and loaded into another burette;

[0081] A 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise at a certain temperature until the pH was 12, and then the temperature was kept at 80 ℃ and stirred for 6 h;

[0082] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and then a ternary high-copper Cu4Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0083] The product quality was measured to be 4.2 g, the metal Cu content was 49.5 wt%, the metal Fe content was 7.2 wt%, the metal Ce content was 16.3 wt%, the specific surface area was 65 m 2 / g, and the crystallinity was 79%. Example 10

[0084] 5.56 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and then loaded into a burette, and a prepared 2 M NaOH aqueous solution was loaded into another burette;

[0085] A 1 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise at a certain temperature until the pH was 12, and then the temperature was kept at 80 ℃ and stirred for 6 h;

[0086] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and then a ternary high-copper Cu5Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0087] The product quality was measured to be 5.1 g, the metal Cu content was 53.6 wt%, the metal Fe content was 6.8 wt%, the metal Ce content was 16.8 wt%, the specific surface area was 75 m 2 / g, and the crystallinity was 89%. Example 11

[0088] 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and then loaded into a burette, and a prepared 1.5 M NaOH aqueous solution was loaded into another burette;

[0089] A 0.5 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise at a certain temperature until the pH was 12, and then the temperature was kept at 80 ℃ and stirred for 6 h;

[0090] The obtained coprecipitate was washed to neutral with deionized water, dried, and calcined at 450 ℃ for 6 h to obtain the ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0091] The product mass was measured to be 3.6 g, the metal Cu content was 40.1 wt%, the metal Fe content was 6.5 wt%, the metal Ce content was 15.2 wt%, the specific surface area was 62 m 2 / g, and the crystallinity was 87%. Example 12

[0092] After 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were uniformly mixed, they were loaded into a burette, and a prepared 1.5 M NaOH aqueous solution was loaded into another burette;

[0093] The 1.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 12 at a certain temperature, and stirred at 80 ℃ for 6 h;

[0094] The obtained coprecipitate was washed to neutral with deionized water, dried, and calcined at 450 ℃ for 6 h to obtain the ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0095] The product mass was measured to be 4.1 g, the metal Cu content was 43.2 wt%, the metal Fe content was 7.4 wt%, the metal Ce content was 19.2 wt%, the specific surface area was 73 m 2 / g, and the crystallinity was 91%. Example 13

[0096] After 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were uniformly mixed, they were loaded into a burette, and a prepared 2.5 M NaOH aqueous solution was loaded into another burette;

[0097] The 2.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 12 at a certain temperature, and stirred at 80 ℃ for 6 h;

[0098] The obtained coprecipitate was washed to neutral with deionized water, dried, and calcined at 450 ℃ for 6 h to obtain the ternary high-copper Cu3Fe 0.5 Ce 0.5Metal oxide catalyst.

[0099] The product mass was measured to be 4.3 g, the metal Cu content was 38.5 wt%, the metal Fe content was 6.7 wt%, the metal Ce content was 17.9 wt%, the specific surface area was 68 m 2 / g, and the crystallinity was 92%. Example 14

[0100] After 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were uniformly mixed, they were loaded into a burette, and a prepared 3.0 M NaOH aqueous solution was loaded into another burette;

[0101] The 3.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 12 at a certain temperature, and stirring was performed at 80°C for 6 h;

[0102] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450°C for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0103] The product mass was measured to be 5.3 g, the metal Cu content was 42.1 wt%, the metal Fe content was 6.6 wt%, the metal Ce content was 17.4 wt%, the specific surface area was 54 m 2 / g, and the crystallinity was 95%. Example 15

[0104] After 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were uniformly mixed, they were loaded into a burette, and a prepared 2 M NaOH aqueous solution was loaded into another burette;

[0105] The 1.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 10 at a certain temperature, and stirring was performed at 50°C for 9 h;

[0106] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450°C for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 Metal oxide catalyst.

[0107] The product quality is measured as 3.4 g, the metal Cu content is 33.2 wt%, the metal Fe content is 5.5 wt%, the metal Ce content is 14.2 wt%, the specific surface area is 53 m 2 / g, and the crystallinity is 75%. Example 16

[0108] After mixing 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water uniformly, they are loaded into a burette, and a prepared 2 M NaOH aqueous solution is loaded into another burette;

[0109] The 1.0 M Na2CO3 aqueous solution is added into a four-necked flask, a pH meter is inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution are added dropwise at a certain temperature until the pH is 12, and then the stirring is performed at 50 ℃ for 10 h;

[0110] The obtained coprecipitate is washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and then a ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst is obtained.

[0111] The product quality is measured as 4.4 g, the metal Cu content is 35.7 wt%, the metal Fe content is 6.3 wt%, the metal Ce content is 16.9 wt%, the specific surface area is 64 m 2 / g, and the crystallinity is 83%. Example 17

[0112] After mixing 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water uniformly, they are loaded into a burette, and a prepared 2 M NaOH aqueous solution is loaded into another burette;

[0113] The 1.0 M Na2CO3 aqueous solution is added into a four-necked flask, a pH meter is inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution are added dropwise at a certain temperature until the pH is 11, and then the stirring is performed at 70 ℃ for 7 h;

[0114] The obtained coprecipitate is washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and then a ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst is obtained.

[0115] The product quality is measured as 5.1 g, the metal Cu content is 43.4 wt%, the metal Fe content is 7.2 wt%, the metal Ce content is 17.1 wt%, the specific surface area is 61 m 2 / g, and the crystallinity is 89%. Example 18

[0116] 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and loaded into a burette, and a prepared 2 M NaOH aqueous solution was loaded into another burette;

[0117] The 1.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 13 at a certain temperature, and stirred at 100 ℃ for 4 h;

[0118] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 450 ℃ for 6 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst was obtained.

[0119] The product mass was measured to be 4.5 g, the metal Cu content was 24.1 wt%, the metal Fe content was 3.5 wt%, the metal Ce content was 13.2 wt%, the specific surface area was 54 m 2 / g, and the crystallinity was 74%. Example 19

[0120] 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water were mixed uniformly and loaded into a burette, and a prepared 2 M NaOH aqueous solution was loaded into another burette;

[0121] The 1.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise to a pH of 12 at a certain temperature, and stirred at 80 ℃ for 6 h;

[0122] The obtained coprecipitate was washed to neutral with deionized water, dried, calcined at 400 ℃ for 7 h, and a ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst was obtained.

[0123] The product mass was measured to be 5.7 g, the metal Cu content was 34.1 wt%, the metal Fe content was 7.5 wt%, the metal Ce content was 14.7 wt%, the specific surface area was 67 m 2 / g, and the crystallinity was 78%. Example 20

[0124] A burette was filled with 3.34 g of copper nitrate trihydrate, 0.93 g of iron nitrate nonahydrate, 1 g of cerium nitrate hexahydrate and deionized water, and another burette was filled with 2 M NaOH aqueous solution;

[0125] A 1.0 M Na2CO3 aqueous solution was added into a four-necked flask, a pH meter was inserted below the liquid surface, and the mixed salt solution and the NaOH aqueous solution were added dropwise at a certain temperature until the pH was 12. The mixture was stirred at 80 ℃ for 6 h;

[0126] The obtained coprecipitate was washed with deionized water until neutral, dried, and calcined at 500 ℃ for 5 h to obtain the ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst.

[0127] The product had a mass of 5.7 g, a metal Cu content of 38.1 wt%, a metal Fe content of 7.5 wt%, a metal Ce content of 16.1 wt%, a specific surface area of 47 m 2 / g, and a crystallinity of 69%. Comparative Example 1

[0128] Cu3Fe 0.5 Ce 0.5 metal oxide catalyst, comprising the following steps:

[0129] 1) Synthesis of the carrier CeO2 by a hydrothermal method:

[0130] 1.736 g of cerium nitrate hexahydrate was weighed into 10 mL of deionized water, and 20 g of NaOH was weighed into 70 mL of deionized water and cooled to room temperature. The cerium nitrate hexahydrate solution was added dropwise to the NaOH solution while stirring magnetically. After stirring for 30 min, the mixture was transferred to a hydrothermal kettle and kept at 100 ℃ for 24 h. After cooling, the mixture was centrifuged and washed with deionized water and ethanol three times each, and then dried at 60 ℃ to obtain the carrier CeO2.

[0131] 2) Synthesis of the CuFe / CeO2 metal oxide by an equal-volume impregnation method:

[0132] 3.34 g of copper nitrate trihydrate and 0.93 g of iron nitrate nonahydrate were dissolved in deionized water, and then added dropwise to 1.23 g of dried CeO2 while stirring. After aging for 24 h, the mixture was dried at 110 ℃ for 8 h, and then calcined at 450 ℃ for 6 h to obtain the CuFe / CeO2 metal oxide catalyst.

[0133] The product quality was measured as 4.1 g, the metal Cu content was 33.1 wt%, the metal Fe content was 5.2 wt%, the metal Ce content was 14.2 wt%, the specific surface area was 35 m 2 / g, and the crystallinity was 56%.

[0134] Comparative Example 2

[0135] Preparation of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst comprises the following steps:

[0136] 1.23 g of cerium nitrate hexahydrate was dissolved in 16 mL of ethanol and mixed uniformly, 1.40 mL of 1,2-epoxypropane was slowly added dropwise into the solution, 0.87 g of copper nanoparticles and 0.12 g of iron nanoparticles were added respectively, aging for 5 days, drying at 60 ℃ for 24 h, calcining at 300 ℃ for 2 h, and finally grinding to obtain a CuFe / CeO2 metal oxide.

[0137] The product quality was measured as 3.1 g, the metal Cu content was 11.1 wt%, the metal Fe content was 2.5 wt%, the metal Ce content was 9.2 wt%, the specific surface area was 21 m 2 / g, and the crystallinity was 61%.

[0138] The following examples screen the condition parameters of the catalytic reaction.

[0139] As can be seen from Examples 1-16 and Comparative Examples 1 and 2, the one-step coprecipitation method has the advantages of more convenient operation, high catalyst yield, and high crystallinity compared with the equal-volume impregnation method and the sol-gel method. In addition, the Cu3Fe 0.5 Ce 0.5 metal oxide catalyst synthesized by the one-step coprecipitation method has stronger interaction between the metal Cu, Fe, and Ce and highly uniform dispersion of the metal elements, and therefore has higher catalytic activity.

[0140] Example 21

[0141] The performance of the ternary high-copper Cu3Fe 0.5 Ce 0.5 metal oxide catalyst prepared in Example 1 in catalyzing the anilization and amine saltization of aniline and CO2 was studied.

[0142] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.6 g of the Cu3Fe 0.5 Ce 0.5 metal oxide catalyst were added into a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and reaction was carried out at 160 ℃ for 7 h.

[0143] After the reaction, the catalyst was separated by centrifugation, and the reaction liquid was detected and analyzed by HPLC 8860 high performance liquid chromatography. The structure of the product was confirmed by high performance liquid chromatography as N,N'-diphenylurea, the selectivity was 99.9%, and the aniline conversion rate was 32.9%.

[0144] Test conditions:

[0145] Agilent HPLC liquid phase detection system was used, and C18 chromatographic column was used. The experimental parameters were set as follows: the mobile phase was V 甲醇 :V 水 =52:48; the injection amount was 5 µL; the flow rate was 0.5 mL / min; the column temperature was 30 ℃; the ultraviolet detector was used, and the detection wavelength was 254 nm.

[0146] Example 22

[0147] 5.0 mL of aniline, 5.0 mL of methanol and 0.6 g of Cu3Fe 0.5 Ce 0.5 metal oxide catalyst were added to a micro magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0148] The structure of the product was confirmed by high performance liquid chromatography as N,N'-diphenylurea, the selectivity was 95.2%, the selectivity of the by-product acetanilide was 4.8%, and the aniline conversion rate was 23.4%.

[0149] Example 23

[0150] 5.0 mL of aniline, 5.0 mL of deionized water and 0.6 g of Cu3Fe 0.5 Ce 0.5 metal oxide catalyst were added to a micro magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0151] The structure of the product was confirmed by high performance liquid chromatography as N,N'-diphenylurea, the selectivity was 78.3%, the selectivity of the by-product acetanilide was 21.7%, and the aniline conversion rate was 13.5%.

[0152] Example 24

[0153] 5.0 mL of aniline, 5.0 mL of deionized water and 0.6 g of Cu3Fe 0.5 Ce 0.5 metal oxide catalyst were added to a micro magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0154] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 92.9%, a selectivity of the by-product acetanilide of 7.1%, and an aniline conversion rate of 26.9%.

[0155] Example 25

[0156] 7.5 mL of aniline, 2.5 mL of acetonitrile, and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 °C for 7 h.

[0157] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 99.8%, a selectivity of the by-product acetanilide of 0.2%, and an aniline conversion rate of only 2.5%, indicating that reducing the amount of solvent acetonitrile used can significantly reduce the reactivity, and further indicating that the solvent acetonitrile is crucial to the reaction.

[0158] Example 26

[0159] 2.5 mL of aniline, 7.5 mL of acetonitrile, and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 °C for 7 h.

[0160] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 78.7%, a selectivity of the by-product acetanilide of 21.3%, and an aniline conversion rate of 25.1%.

[0161] Example 27

[0162] 1.0 mL of aniline, 9.0 mL of acetonitrile, and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 °C for 7 h.

[0163] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 25.1%, a selectivity of the by-product acetanilide of 75.9%, and an aniline conversion rate of only 15.2%. This is because the excessive addition of acetonitrile promotes the generation of by-products, greatly reducing the selectivity of the product.

[0164] Example 28

[0165] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.4 g of Cu3Fe0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0166] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity of which was 99.4%, the selectivity of the by-product acetanilide was 0.6%, and the conversion rate of aniline was 18.2%.

[0167] Example 29

[0168] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.8 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0169] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity of which was 99.1%, the selectivity of the by-product acetanilide was 0.9%, and the conversion rate of aniline was 25.7%.

[0170] Example 30

[0171] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 1.0 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0172] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity of which was 99.3%, the selectivity of the by-product acetanilide was 0.7%, and the conversion rate of aniline was 15.1%. It was because Cu3Fe 0.5 Ce 0.5 The use of too low or too high amount of the metal oxide catalyst can greatly reduce the reaction efficiency.

[0173] Example 31

[0174] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.6 g of Cu2Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0175] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity of which was 98.9%, the selectivity of the by-product acetanilide was 1.1%, and the conversion rate of aniline was 23.9%.

[0176] Example 32

[0177] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu4Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, and after filling with 1 MPa of CO2, it was reacted at 160 °C for 7 h.

[0178] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 99.0%, a selectivity of the by-product acetanilide of 1.0%, and a conversion rate of aniline of 25.8%.

[0179] Example 33

[0180] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu5Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, and after filling with 1 MPa of CO2, it was reacted at 160 °C for 7 h.

[0181] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 99.3%, a selectivity of the by-product acetanilide of 0.7%, and a conversion rate of aniline of 19.9%. By adjusting the molar ratio of copper to iron, it was found that when the ratio of copper to iron was 6:1, the catalytic performance was best, as shown in Table 2. The reason for this is that Cu acts as a key active site and plays a crucial role in the catalytic reaction, but when the amount of Cu used is too much, it can cause the metal oxide to agglomerate and clump, thereby reducing the catalytic activity. Figure 5

[0182] Example 34

[0183] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, and after filling with 0.5 MPa of CO2, it was reacted at 160 °C for 7 h.

[0184] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, with a selectivity of 99.5%, a selectivity of the by-product acetanilide of 0.5%, and a conversion rate of aniline of 26.2%.

[0185] Example 35

[0186] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu3Fe 0.5 Ce​0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 3.0 MPa of CO2 was filled, and then reacted at 160 °C for 7 h.

[0187] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, the selectivity of which was 98.7%, the selectivity of the by-product acetanilide was 1.3%, and the conversion rate of aniline was 17.2%.

[0188] Example 36

[0189] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1.0 MPa of CO2 was filled, and then reacted at 100 °C for 10 h.

[0190] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, the selectivity of which was 73.2%, the selectivity of the by-product acetanilide was 26.8%, and the conversion rate of aniline was 12.9%.

[0191] Example 37

[0192] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1.0 MPa of CO2 was filled, and then reacted at 200 °C for 3 h.

[0193] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, the selectivity of which was 81.8%, the selectivity of the by-product acetanilide was 18.2%, and the conversion rate of aniline was 10.9%.

[0194] Example 38

[0195] Cu3Fe 0.5 Ce 0.5 Metal oxide recycling test:

[0196] 5.0 mL of aniline, 5.0 mL of acetonitrile, and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1.0 MPa of CO2 was filled, and then reacted at 160 °C for 7 h.

[0197] After the reaction, the catalyst was separated by centrifugation, washed with deionized water and anhydrous ethanol several times, and then placed in a drying oven at 100 ℃ for 12 hours. The dried catalyst was recycled for five times under the same catalytic conditions, and the catalytic effect was as shown in Table 1. Figure 6 As shown in Table 1, the results show that the catalytic activity remains basically unchanged after five cycles.

[0198] Comparative Example 3

[0199] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst (prepared by the impregnation method) was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0200] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity was 97.1%, the selectivity of the by-product acetanilide was 2.9%, and the conversion rate of aniline was 22.1%.

[0201] Comparative Example 4

[0202] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu3Fe 0.5 Ce 0.5 The metal oxide catalyst (prepared by the sol-gel method) was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0203] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity was 92.9%, the selectivity of the by-product acetanilide was 7.1%, and the conversion rate of aniline was 17.2%.

[0204] Comparative Example 5

[0205] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu3Fe

[0206] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenyl urea, the selectivity was 96.3%, the selectivity of the by-product acetanilide was 3.7%, and the conversion rate of aniline was 14.1%.

[0207] Comparative Example 6

[0208] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Cu3Fe 0.5 The metal oxide catalyst was added to a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then reacted at 160 ℃ for 7 h.

[0209] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, the selectivity of which was 98.1%, the selectivity of the by-product acetanilide was 1.9%, and the conversion rate of aniline was 23.2%.

[0210] Comparative Example 7

[0211] 5.0 mL of aniline, 5.0 mL of acetonitrile and 0.6 g of Fe 0.5 Ce 0.5 The metal oxide catalyst was added into a micro-magnetic stirring reaction kettle, 1 MPa of CO2 was filled, and then the reaction was carried out at 160 DEG C for 7 h.

[0212] The structure of the product was confirmed by high performance liquid chromatography to be N,N'-diphenylurea, the selectivity of which was 93.2%, the selectivity of the by-product acetanilide was 6.8%, and the conversion rate of aniline was 4.1%.

[0213] The ternary high-copper Cu3Fe x Fe y Ce 0.5 The metal oxide catalyst is prepared by one-step coprecipitation, and the oxide structure formed by various metal ions enhances the activity and stability of the catalyst. The catalyst has the advantages of economy, high efficiency, green environmental protection and the like, and can improve the shortcomings of other traditional catalysts, such as poor recycling and poor recycling.

[0214] The preparation method is convenient to operate and has good reproducibility. The ternary high-copper Cu3Fe 0.5 Ce 0.5 The metal oxide is used for catalyzing the reaction of aniline and CO2, the selectivity of the prepared N,N'-diphenylurea is as high as 99.9%, the conversion rate of aniline is as high as 32.9%, the catalyst still maintains high catalytic activity after multiple cycles, and the metal is not lost, so the catalyst can be applied in the field of catalytic synthesis of N,N'-diphenylurea compounds and the like, and has certain industrial application prospect.

[0215] 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, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all should be covered in the scope of the present application.

Claims

1. A ternary high-copper Cu x Fe y Ce 0.5 metal oxide catalyst characterized by: The structure of the ternary high-copper metal oxide is Cu x Fe y Ce 0.5 wherein x and y respectively represent the amount of substance of Cu, Fe, and x:y = 4:1~10:1; The ternary high-copper Cu x Fe y Ce 0.5 The metal oxide catalyst has the following characteristic X-ray powder diffraction pattern PXRD: ， wherein the X-ray powder diffraction pattern is based on a relative intensity scale in which the strongest line is assigned a value of 100, and where the corresponding relative intensities are: w represents weak, i.e. < 20; m represents medium, i.e. > 20 to < 40; s represents strong, i.e. > 40 to < 60; the ternary high-copper Cu x Fe y Ce 0.5 The specific surface area of the metal oxide catalyst is 36 to 77 m 2 / g, and the crystallinity is 70 to 100%.

2. The ternary high-copper Cu x Fe y Ce 0.5 Process for the preparation of a metal oxide catalyst, characterized in that: The application relates to a method for preparing a copper-iron-cerium composite oxide catalyst, which comprises the following steps: 1) preparing a mixed solution of copper salt, iron salt, cerium nitrate hexahydrate and deionized water; 2) adding the mixed salt solution and NaOH aqueous solution into Na2CO3 aqueous solution drop by drop, adjusting pH, and stirring at constant temperature to obtain a coprecipitate; 3) washing the obtained coprecipitate with deionized water to neutrality, drying, calcination, obtaining the ternary high-copper Cu x Fe y Ce 0.5 metal oxide catalyst.

3. The production method according to claim 2, characterized by: In step 1), the copper salt is one or a mixture of copper nitrate trihydrate, copper acetate monohydrate, copper sulfate pentahydrate and copper chloride dihydrate, and the amount of copper salt is 2.36-3.34 g per 1 g of cerium nitrate hexahydrate; the iron salt is one or a mixture of nitrate ferric nonahydrate, iron acetate, iron sulfate and iron chloride hexahydrate, and the amount of iron salt is 0.40-0.93 g per 1 g of cerium nitrate hexahydrate.

4. The production method according to claim 2, characterized by: In step 2), the concentration of the NaOH aqueous solution is 1.5 M-3.0 M, and the concentration of the Na2CO3 aqueous solution is 0.5 M-3.0 M.

5. The production method according to claim 2, characterized by: In step 2), the pH is adjusted to 10-13, the stirring temperature is 50-100 DEG C, and the stirring time is 4-9 h.

6. The production method according to claim 2, characterized by: In step 3), the calcination temperature is 400-500 DEG C, and the calcination time is 5-7 h.

7. The ternary high-copper Cu x Fe y Ce 0.5 Use of a metal oxide catalyst, characterized in that: The ternary high-copper Cu x Fe y Ce 0.5 The metal oxide catalyst is used for catalyzing the reaction of aniline and CO2 to prepare N,N'-diphenylurea, and the preparation method is to mix aniline, a solvent and Cu x Fe y Ce 0.5 The metal oxide catalyst is mixed, CO2 with a certain pressure is filled in, and then reacted at 100-200 ℃ for 3-10 h, so that N,N'-diphenylurea is obtained.

8. Use according to claim 7, characterized in that: The solvent is one or a mixture of acetonitrile, methanol, deionized water and anhydrous ethanol; the volume ratio of aniline to solvent is 3:1-1:10; the amount of catalyst is 0.08-0.6 g per 1 ml of aniline; the amount of catalyst is 0.4-1.0 g; and the pressure is 0.5-3.0 MPa.

Images