The invention relates to a non-noble metal catalyst Cu-ZnO / TiO2-P25, which is used for catalytically synthesizing N, Napos in a heterogeneous system. Application of-dicyclohexyl p-phenylenediamine

Abstract

The invention relates to application of a non-noble metal catalyst Cu-ZnO / TiO2 in catalytic synthesis of N, N '-dicyclohexyl p-phenylenediamine in a heterogeneous system, and belongs to the technical field of catalyst preparation and application. According to the catalyst, zinc nitrate hexahydrate serves as a zinc source, copper nitrate trihydrate serves as a copper source, P25 type titanium dioxide serves as a carrier, metal is loaded on titanium dioxide through a fractional precipitation method, the titanium dioxide is put into a tubular furnace for hydrogen reduction, a catalyst Cu-ZnO / TiO2 is obtained, then the catalyst Cu-ZnO / TiO2 is dispersed in a solvent, and the novel rubber anti-aging agent N, N-dimethylformamide is synthesized by catalyzing a photo-thermal reduction amination reaction of p-phenylenediamine and cyclohexanone. The catalyst is N, N '-dicyclohexyl p-phenylenediamine. Wherein the Cu-ZnO / TiO2 catalyst with the content of copper being 7% and the content of zinc oxide being 4% has excellent catalytic performance, the conversion rate of p-phenylenediamine reaches 100% and the selectivity of N, N '-dicyclohexyl p-phenylenediamine reaches 99.9% when the hydrogen pressure is 6 MPa, the temperature is 200 DEG C and the reaction is performed for 10 h. The preparation method is simple, low in cost and high in catalytic selectivity, and has a wide industrialization prospect.

Description

Technical Field

[0001] The present invention belongs to the field of non-noble metal catalysts, and particularly relates to the application of a non-noble metal catalyst Cu-ZnO / TiO2 in the heterogeneous system for photocatalytic and thermal reduction amination of p-phenylenediamine and cyclohexanone to synthesize a novel rubber antioxidant N,N' -dicyclohexyl-p-phenylenediamine. Background Art

[0002] During the long-term storage and use of rubber and its products, they will be affected by heat, oxygen, ozone, variable-valence metal ions, mechanical stress, light, high-energy rays, as well as the erosion of other chemical substances and molds, resulting in a decline in physical and mechanical properties and a reduction in elasticity. This phenomenon is called aging. In order to delay or inhibit this aging process, certain chemical substances need to be added to rubber and its products, and such substances are antioxidants. Rubber antioxidants are an important type of rubber additive, playing a key role in extending the service life of rubber, and are widely used in automobile tires, rubber hoses, rubber belts, and other industrial products. Traditional rubber antioxidants such as N -(1,3-dimethylbutyl)- N' -phenyl-p-phenylenediamine (6PPD) is an excellent anti-ozonant and antioxidant, and is particularly outstanding in protecting against fatigue and ozone cracking. However, the latest research has found that when 6PPD is exposed to sunlight and air, it will be converted into 6PPD-quinone (6PPDQ), which will cause poisoning and even death of salmon and other aquatic wild animals when it enters rivers, and threatens human health. Therefore, there is an urgent need to develop new environmentally friendly and non-toxic rubber antioxidants.

[0003] N,N' -dicyclohexyl-p-phenylenediamine (CCPD) is a safe and environmentally friendly antioxidant and can be used as a substitute for 6PPD. Its main preparation method is the one-step reduction amination method, which has the advantages of low production cost and high yield, and is a safe and environmentally friendly preparation method. Ding Junwei et al. from Qingdao University of Science and Technology used sulfided Pt / C as a catalyst to catalyze the reduction amination of 4-aminodiphenylamine and methyl isopentyl ketone to synthesize N -(1,4-dimethylpentyl)- N’ -phenyl-p-phenylenediamine, and the yield can reach 99%. However, this catalyst is basically deactivated after being used 25 times. Symon Ted prepared a Pt / Al2O3 catalyst for catalytic reduction amination, and the product yield was 97%.

[0004] The above reaction systems all belong to thermal catalytic systems, and there are problems such as harsh reaction conditions and high energy consumption. Compared with thermal catalysis, photothermal catalysis is a new technology that combines photocatalysis and thermal catalysis. It can lower the reaction energy barrier, make the reaction conditions milder, promote the mass transfer and diffusion of reaction species and photogenerated carriers, accelerate their migration to the catalyst surface and interface to participate in the reaction, thereby increasing the reaction rate and regulating the catalytic reaction path and product selectivity. O. Wenger et al. first reported the use of [Ru(bpy)3]Cl2 photosensitizer under 470 nm blue light to achieve the reductive amination of ketones to prepare secondary amines through photoredox reactions under mild conditions. Ru II Photoexcitation promotes the reduction of iminium ions to electron-rich α-aminoalkyl radical intermediates, which are rapidly hydrogenated by the H atoms on the mercapto group to form secondary amines. However, there is currently no report on the research of heterogeneous photothermal catalytic reductive amination for the preparation of environmentally friendly rubber antioxidants.

[0005] In summary, although noble metal catalysts have made certain progress in the synthesis of environmentally friendly antioxidants by reductive amination, the research based on photothermal catalysis, especially non-noble metal-based photothermal systems, remains blank. Therefore, it is of great significance to develop a non-noble metal catalyst for the photothermal catalytic synthesis of new rubber antioxidants. Summary of the Invention

[0006] Aiming at the above problems existing in the existing catalytic synthesis of CCPD, the purpose of the present invention is to provide an application of a non-noble metal catalyst Cu-ZnO / TiO2 in the catalytic synthesis of N,N' -dicyclohexyl-p-phenylenediamine in a heterogeneous system. This preparation method is simple and highly selective, and has industrialization prospects.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions.

[0008] The purpose of the present invention is to provide an application of a non-noble metal catalyst Cu-ZnO / TiO2 in the catalytic synthesis of N,N' -dicyclohexyl-p-phenylenediamine. Using Cu-ZnO / TiO2 as the catalyst, p-phenylenediamine and cyclohexanone as the reactants, and cyclohexane as the solvent, the catalytic reaction is carried out under a hydrogen atmosphere and full-spectrum light irradiation conditions to generate N,N' -dicyclohexyl-p-phenylenediamine.

[0009] Preferably, under the conditions of a hydrogen pressure of 6 MPa, a temperature of 200 °C, and 300 W full-spectrum light irradiation, using Cu-ZnO / TiO2 as the catalyst, p-phenylenediamine and cyclohexanone as the reactants, and cyclohexane as the solvent, after the catalytic reaction for 10 h, when the conversion rate of p-phenylenediamine is 100%, N,N' the selectivity of -dicyclohexyl-p-phenylenediamine is 99.9%.

[0010] N,N' - Dicyclohexyl-p-phenylenediamine, abbreviated as CCPD in the text, with the same meaning.

[0011] For the above non-noble metal catalyst Cu-ZnO / TiO2, Cu and ZnO are loaded on P25-type TiO2. The loading amount of Cu is 1-9 wt% of the catalyst, and the loading amount of ZnO is 2-8 wt% of the catalyst.

[0012] Preferably, the loading amount of Cu is 7 wt% of the catalyst, and the loading amount of ZnO is 4 wt% of the catalyst.

[0013] In the Cu-ZnO / TiO2 catalyst, the method of expressing the loading amounts of Cu and ZnO is directly abbreviated as 1-9% and 2-8% in the subsequent content of this article, and their meanings are the same as those of 1-9 wt% and 2-8 wt% recorded in this article.

[0014] The preparation steps of the above non-noble metal catalyst Cu-ZnO / TiO2 are as follows: (1) Add P25-type TiO2 and zinc nitrate hexahydrate to pure water and stir evenly to obtain a suspension. Place it in a water bath at 60-80 °C, stir vigorously, and gradually add the precipitant - Na2CO3 solution to adjust the pH to 10-12. Continue to stir the obtained mixture for 0.5 h, collect the formed precipitate, wash it until the pH value is 7, place the obtained sample in a vacuum drying oven at 60 °C for drying for 12 h, and calcine it in a muffle furnace under an air atmosphere to obtain the ZnO / TiO2 support; (2) Add the ZnO / TiO2 support and copper nitrate trihydrate to pure water and stir evenly. Place the obtained suspension in a water bath at 50-70 °C, stir vigorously, and gradually add the precipitant - Na2CO3 solution to adjust the pH to 8-10. Continue to stir the obtained mixture for 2 h, collect the formed precipitate, wash it until the pH value is 7 and then place it in a vacuum drying oven at 60 °C for drying for 12 h to obtain the unreduced Cu-ZnO / TiO2; (3) Place the unreduced catalyst Cu-ZnO / TiO2 in a tubular furnace and heat and reduce it under a hydrogen atmosphere, and naturally cool it to room temperature to obtain Cu-ZnO / TiO2.

[0015] In the above preparation method, zinc sulfate or zinc chloride can also be used instead of zinc nitrate hexahydrate in step (1), and copper sulfate or copper chloride can also be used instead of copper nitrate trihydrate in step (2), and the technical effects produced are the same.

[0016] Preferably, the molar ratio of P25-type TiO2 to zinc nitrate hexahydrate in step (1) is 3-14:1.

[0017] Preferably, in the step (2), the mass ratio of the ZnO / TiO2 support to copper nitrate trihydrate is 2-26:1.

[0018] Preferably, in the steps (1) and (2), the concentration of the Na2CO3 solution is 0.1 g / mL.

[0019] Preferably, in the step (1), the heating rate of the muffle furnace is 5 °C / min, the calcination temperature is 250-450 °C, and the calcination time is 3.5-4.5 h. Since the calcination of the support is to obtain a support with a stable structure, it is necessary to control reasonable calcination temperature and time.

[0020] Preferably, in the step (2), the heating rate of the tubular furnace is 5 °C / min, the reduction temperature in the tubular furnace is 200-400 °C, and the reduction time is 1-3 h.

[0021] The non-noble metal catalyst Cu-ZnO / TiO2 of the present invention catalyzes the synthesis in a heterogeneous system N,N' -dicyclohexyl-p-phenylenediamine, and the specific steps are as follows: (1) Select a stainless steel high-pressure photothermal reaction kettle and insert a glass container as the inner lining of the reaction kettle; (2) Weigh the catalyst Cu-ZnO / TiO2 into the high-pressure photothermal reaction kettle, and then weigh p-phenylenediamine and cyclohexanone and dissolve them in cyclohexane solvent. After ultrasonic dispersion, place the mixed solution in the high-pressure photothermal reaction kettle; (3) After sealing the reaction kettle, evacuate it three times with hydrogen at a pressure of 1 MPa, maintain the hydrogen pressure at 1 MPa at room temperature, and check the airtightness of the reaction kettle; (4) First heat the reaction kettle to 200 °C, under the condition of 300 W full-spectrum light irradiation, continue to introduce hydrogen to 6 MPa, and maintain the temperature and pressure in the reaction kettle for reaction for 1 h; (5) After the reaction is completed, cool to room temperature, then open the gas valve of the high-pressure photothermal reaction kettle, and release the gas in the kettle until the pressure is 0 to complete the reaction process.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adopts the deposition-precipitation method to prepare Cu-ZnO / TiO2, which uses non-noble metals as the active phase and P25-type TiO2 as the support, greatly reducing the cost of raw materials, and the preparation method is simple, green and environmentally friendly, and has the prospect of industrialization; The 7% Cu-4% ZnO / P25 catalyst prepared by the preparation method of the present invention has excellent catalytic performance; under the reaction conditions of a hydrogen pressure of 6 MPa, a temperature of 200 °C, 300 W full-spectrum light irradiation, a reaction time of 10 h, and 0.2 g of the catalyst, when the conversion rate of 0.108 g of p-phenylenediamine is 100%, the selectivity of CCPD is 99.9%. Description of the Drawings

[0023] Figure 1 XRD pattern of the Cu-ZnO / TiO2 catalyst prepared in Example 2.

[0024] Figure 2 Time-course graph of the Cu-ZnO / TiO2 catalyst prepared in Example 2.

[0025] Figure 3 Performance graph of the stability experiment of the Cu-ZnO / TiO2 catalyst prepared in Example 2.

[0026] Figure 4 TEM image of the Cu-ZnO / TiO2 catalyst prepared in Example 2. Detailed Description of the Invention

[0027] The technical solution of the present invention will be further described below with specific examples, but the protection scope of the present invention is not limited thereto.

[0028] In the present invention, Cu-ZnO / TiO2 is prepared by loading different proportions of Cu and ZnO on P25-type TiO2 as an example to detect the performance and parameters of the product and determine the optimal performance of the product.

[0029] In the following specific Examples 1-10, the following steps are used to prepare the catalyst: (1) P25-type TiO2 and zinc nitrate hexahydrate are added to pure water and stirred evenly to obtain a suspension, which is placed in a water bath at 70 °C and stirred vigorously. A precipitant - Na2CO3 solution with a concentration of 0.1 g / mL is added dropwise to adjust the pH to 11. The resulting mixture is stirred for another 0.5 h, and the formed precipitate is collected and washed until the pH value is 7. The obtained sample is placed in a vacuum drying oven at 60 °C and dried for 12 h, and then calcined in a muffle furnace under an air atmosphere. The muffle furnace is heated to 350 °C at a heating rate of 5 °C / min, and the calcination time is 3 h to obtain the ZnO / TiO2 support; (2) The ZnO / TiO2 support and copper nitrate trihydrate were added to pure water and stirred evenly. The resulting suspension was placed in a water bath at 60 °C and stirred vigorously. A precipitant - Na2CO3 solution with a concentration of 0.1 g / mL was added dropwise to adjust the pH to 9. The resulting mixture was stirred for another 2 h. The formed precipitate was collected, washed until the pH value reached 7, and then placed in a vacuum drying oven at 60 °C for drying for 12 h to obtain unreduced Cu-ZnO / TiO2. (3) The unreduced catalyst Cu-ZnO / TiO2 was placed in a tubular furnace and heated and reduced under a hydrogen atmosphere for 2 h. It was heated to 300 °C at a heating rate of 5 °C / min, with a reduction time of 2 h, and then cooled naturally to room temperature to obtain Cu-ZnO / TiO2.

[0030] Among them, in the dosage of raw materials, by controlling the molar ratio of P25-type TiO2 to zinc nitrate hexahydrate to be 3 - 14:1, and the mass ratio of the ZnO / TiO2 support to copper nitrate trihydrate to be 2 - 26:1, Cu and ZnO can be loaded on the catalyst in different proportions.

[0031] The photocatalytic and thermal catalytic reduction amination synthesis of CCPD of the catalyst prepared by the above method was tested as follows: It was carried out in a 200 mL stainless steel high-pressure photocatalytic and thermal reaction kettle, and a glass container was inserted as the inner lining of the reaction kettle; 0.2 g of the catalyst was weighed into the high-pressure photocatalytic and thermal reaction kettle, and then 0.108 g of p-phenylenediamine, 0.196 g of cyclohexanone and 20 mL of cyclohexane were weighed. The p-phenylenediamine and cyclohexanone were dissolved in cyclohexane, and after ultrasonic dispersion, the mixture was placed in the high-pressure photocatalytic and thermal reaction kettle. After sealing the reactor, it was evacuated three times with hydrogen (1 MPa), the hydrogen pressure was increased to 1 MPa at room temperature, and the airtightness was checked. After checking the airtightness, the magnetic stirrer speed was adjusted to 550 rpm. When the temperature of the reaction kettle reached 200 °C, a 300 W full-spectrum xenon lamp was turned on, and hydrogen was introduced until the pressure reached 6 MPa, and the timing started. After the reaction for 1 h, it was cooled to room temperature, and then the gas valve of the high-pressure photocatalytic and thermal reaction kettle was opened to release the gas in the kettle until the pressure was 0 MPa.

[0032] After filtering the reaction solution, 0.4 μL was aspirated with a microsyringe and injected into the gas chromatograph. Among them, the hydrogen flow rate of the gas chromatograph was set to 40 - 60 mL / min, the air flow rate was 200 - 300 mL / min, and the carrier gas flow rate was 2 - 3 mL / min. The injection temperature was set to 280.0 °C, the initial temperature of the column oven was set to 150 °C and held for 10 min, then it was heated to 280 °C at a rate of 25 °C / min and held for 20 min, and the FID temperature was set to 280.0 °C. Using n-dodecane as the internal standard, the conversion rate and selectivity of the photocatalytic and thermal reduction amination synthesis of CCPD of the catalysts in different examples were calculated by gas chromatography.

[0033] Application of 7% Cu - 2% ZnO / TiO₂ in Catalytic Photothermal Reductive Amination for the Synthesis of CCPD The catalyst of Example 1 of the present invention was tested for its application in catalytic photothermal reductive amination for the synthesis of CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full - spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p - phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity for CCPD was 73.7%.

[0034] Example 2: Application of 7% Cu - 4% ZnO / TiO₂ in Catalytic Photothermal Reductive Amination for the Synthesis of CCPD The catalyst of Example 2 of the present invention was tested for its application in catalytic photothermal reductive amination for the synthesis of CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full - spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p - phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity for CCPD was 77.2%.

[0035] Example 3: Application of 7% Cu - 6% ZnO / TiO₂ in Catalytic Photothermal Reductive Amination for the Synthesis of CCPD The catalyst of Example 3 of the present invention was tested for its application in catalytic photothermal reductive amination for the synthesis of CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full - spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p - phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity for CCPD was 74.6%.

[0036] Example 4: Application of 7% Cu - 8% ZnO / TiO₂ in Catalytic Photothermal Reductive Amination for the Synthesis of CCPD The catalyst of Example 4 of the present invention was tested for its application in catalytic photothermal reductive amination for the synthesis of CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full - spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p - phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity for CCPD was 72.1%.

[0037] Example 5: Application of 7% Cu - 4% ZnO / TiO₂ in Catalytic Photothermal Reductive Amination for the Synthesis of CCPD The catalyst of Example 5 of the present invention was tested for the application of catalytic photothermal reduction amination to synthesize CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of a hydrogen pressure of 6 MPa, a temperature of 200 °C, 300 W of full-spectrum light irradiation, a reaction time of 10 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine, and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity of CCPD was 99.9%.

[0038] Comparative Example 1: Application of 7% Cu / ZnO in catalytic photothermal reduction amination to synthesize CCPD The 7% Cu / ZnO of this Comparative Example 1 was tested for the application of catalytic photothermal reduction amination to synthesize CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of a hydrogen pressure of 6 MPa, a temperature of 200 °C, 300 W of full-spectrum light irradiation, a reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine, and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity of CCPD was 21.3%.

[0039] Comparative Example 2: Application of 7% Cu / TiO2 in catalytic photothermal reduction amination to synthesize CCPD The 7% Cu / TiO2 of this Comparative Example 2 was tested for the application of catalytic photothermal reduction amination to synthesize CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of a hydrogen pressure of 6 MPa, a temperature of 200 °C, 300 W of full-spectrum light irradiation, a reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine, and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity of CCPD was 55.5%.

[0040] Example 6: Application of 1% Cu - 4% ZnO / TiO2 in catalytic photothermal reduction amination to synthesize CCPD The catalyst of Example 6 of the present invention was tested for the application of catalytic photothermal reduction amination to synthesize CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of a hydrogen pressure of 6 MPa, a temperature of 200 °C, 300 W of full-spectrum light irradiation, a reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine, and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 100%, and the selectivity of CCPD was 69.2%.

[0041] Example 7: Application of 9% Cu - 4% ZnO / TiO2 in catalytic photothermal reduction amination to synthesize CCPD The catalyst of Example 7 of the present invention was tested for the application of catalytic photothermal reduction amination to synthesize CCPD, and the performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full-spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst is 100%, and the selectivity of CCPD is 72.8%.

[0042] Example 8: Application of 7% Cu-4% ZnO / TiO2 in the catalytic photothermal reduction amination for the synthesis of CCPD The catalyst of Example 8 of the present invention was prepared by reduction at a hydrogen reduction temperature of 400 °C, and then the application test of catalytic photothermal reduction amination for the synthesis of CCPD was carried out. The performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full-spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst is 100%, and the selectivity of CCPD is 73.8%.

[0043] Example 9: Application of 7% Cu-4% ZnO / TiO2 in the catalytic photothermal reduction amination for the synthesis of CCPD The catalyst of Example 9 of the present invention was prepared by reduction at a hydrogen reduction temperature of 200 °C, and then the application test of catalytic photothermal reduction amination for the synthesis of CCPD was carried out. The performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, 300 W full-spectrum light irradiation, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst is 100%, and the selectivity of CCPD is 70.4%.

[0044] Example 10: Application of 7% Cu-4% ZnO / TiO2 in the catalytic synthesis of CCPD The catalyst of Example 10 of the present invention was tested for the application of catalytic synthesis of CCPD under lightless conditions. The performance test conditions and results are as follows: Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 °C, reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine and 0.198 g of cyclohexanone, the conversion rate of this catalyst is 100%, and the selectivity of CCPD is 32.6%.

[0045] Example 11: Application of 7% Cu-4% ZnO / TiO2 in the catalytic synthesis of CCPD The catalyst of Example 11 of the present invention was tested for the application of catalytic synthesis of CCPD under room temperature light irradiation conditions. The performance test conditions and results are as follows: Under the reaction conditions of a hydrogen pressure of 6 MPa, a temperature of 20 °C, 300 W of full-spectrum light irradiation, a reaction time of 1 h, 0.2 g of catalyst, 0.108 g of p-phenylenediamine, and 0.198 g of cyclohexanone, the conversion rate of this catalyst was 0%.

[0046] The catalyst prepared in Example 2 was subjected to spectral testing, electron microscopy scanning, catalytic activity testing, and stability testing, and the test results are as follows.

[0047] Figure 1 It is the XRD pattern of the catalyst prepared in Example 2 before and after the catalytic reaction. It can be observed that the characteristic peaks of P25-type TiO2 are obvious, and the characteristic peaks of the (100), (002), and (101) crystal planes belonging to ZnO and the characteristic peak of the Cu(111) crystal plane can be observed in the spectrum. The XRD pattern of the catalyst prepared in Example 2 before and after the catalytic reaction hardly changed, and the size of Cu particles in the catalyst was 5 nm before and after the reaction, indicating that the catalyst has a stable structure and is a heterogeneous catalyst that can be recycled.

[0048] Figure 2 It is the Time-course diagram of the catalyst prepared in Example 2. It can be seen from the figure that at reaction times of 0 h, 1 h, 2 h, 4 h, 8 h, and 10 h, the conversion rate of p-phenylenediamine was 100%, and the selectivities of CCPD were 65.0%, 77.2%, 86.2%, 92.1%, 98.5%, and 99.9% respectively. It can be concluded that the catalyst prepared in Example 2 has high catalytic activity and selectivity.

[0049] Figure 3 It is the stability experiment performance diagram of the catalyst prepared in Example 2. It can be seen from the figure that at the first, second, third, and fourth catalyst recycling times, the conversion rate of p-phenylenediamine was 100%, and the selectivities of CCPD were 77.2%, 76.4%, 77.5%, and 77.8% respectively. It can be concluded that this catalyst has high stability.

[0050] Figure 4 It is the TEM diagram of the catalyst prepared in Example 2. It can be seen from the figure that Cu and ZnO are loaded on P25-type TiO2, and the size of Cu particles is 5 nm.

[0051] The catalytic performance of p-phenylenediamine of the catalyst products obtained under different conditions is shown in Table 1 under the same reaction conditions.

[0052] Table 1: Influence of different loadings on catalytic activity

[0053] As can be seen from Examples 1 - 4 in Table 1, the loading amount of ZnO has a great influence on the catalyst activity. When the loading amount ranges from 2% to 8%, the conversion rate of p-phenylenediamine remains at 100%. The selectivity of CCPD first increases and then decreases, indicating that the catalytic performance of the catalyst also first increases and then decreases, showing a volcano-shaped trend. When the loading amount is 4%, the conversion rate is 100% and the selectivity reaches the highest at 77.2%.

[0054] As can be seen from Examples 2 and 5, when the Cu loading amount is 7% and the ZnO loading amount is 4%, extending the reaction time to 10 h, the conversion rate of p-phenylenediamine remains at 100%, and the selectivity of CCPD increases to 99.9%.

[0055] As can be seen from Examples 2, 6, and 7, the loading amount of Cu still has a great influence on the catalyst activity. When the loading amount ranges from 1% to 9%, the conversion rate of p-phenylenediamine remains at 100%. The selectivity of CCPD first increases and then decreases. When the loading amount is 7%, the conversion rate is 100% and the selectivity reaches the highest at 77.2%.

[0056] As can be seen from Examples 2, Comparative Example 1, and Comparative Example 2, ZnO and Cu have a synergistic effect on the catalytic performance of the catalyst, which can significantly improve the catalytic performance of the catalyst.

[0057] As can be seen from Examples 2, 8, and 9, the reduction temperature of hydrogen also has a great influence on the performance of the catalyst. As the reduction temperature rises from 200 °C to 400 °C, the catalytic performance of the catalyst first increases and then decreases. When the reduction temperature is 300 °C, the catalytic performance of the catalyst reaches the highest.

[0058] As can be seen from Examples 2, 10, and 11, photothermal catalysis can significantly improve the catalytic performance of the catalyst. The reaction performances of thermal catalysis and photocatalysis are both lower than that of photothermal catalysis. At the reaction temperature of 200 °C and under 300 W full-spectrum light illumination, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 77.2%.

[0059] The above are only some embodiments of the present invention and are not used to limit the present invention. Any equivalent changes and modifications made according to the content of the present invention fall within the protection scope of the present invention.

Claims

1. Catalytic synthesis of a non-precious metal catalyst Cu-ZnO / TiO2 in a heterogeneous system N,N' -Application of dicyclohexyl-p-phenylenediamine, characterized in that, Using Cu-ZnO / TiO2 as catalyst, p-phenylenediamine and cyclohexanone as reactants, and cyclohexane as solvent, the catalytic reaction generates N,N' -Dicyclohexyl-p-phenylenediamine.

2. The use according to claim 1, characterized in that: Under the conditions of hydrogen pressure of 6MPa, temperature of 200℃, and 300W full-spectrum illumination, with Cu-ZnO / TiO2 as catalyst, p-phenylenediamine and cyclohexanone as reactants, and cyclohexane as solvent, the catalytic reaction lasted for 10h, and the conversion rate of p-phenylenediamine was 100%. N,N' -The selectivity of dicyclohexyl-p-phenylenediamine is 99.9%.

3. The use according to claim 1, characterized in that: The non-precious metal catalyst Cu-ZnO / TiO2, wherein Cu and ZnO are loaded on P25 type TiO2, the Cu loading is 1-9wt% of the catalyst, and the ZnO loading is 2-8wt% of the catalyst.

4. The use according to claim 3, characterized in that: In the non-precious metal catalyst Cu-ZnO / TiO2, the Cu loading is 7wt% of the catalyst, and the ZnO loading is 4wt% of the catalyst.

5. The use according to claim 3, characterized in that: The preparation steps of the non-precious metal catalyst Cu-ZnO / TiO2 are as follows: (1) P25 TiO2 and zinc nitrate hexahydrate were added to pure water and stirred evenly. The obtained suspension was placed in a water bath at 60-80°C and stirred vigorously. A precipitant - Na2CO3 solution was added dropwise to adjust the pH to 10-12. The obtained mixture was stirred for 0.5 h. The formed precipitate was collected and washed to a pH of 7. The obtained sample was placed in a vacuum drying oven at 60°C and dried for 12 h. It was then placed in a muffle furnace in an air atmosphere and calcined to obtain a ZnO / TiO2 carrier. (2) Add ZnO / TiO2 carrier and copper nitrate trihydrate into pure water and stir evenly. Place the obtained suspension in a water bath at 50-70°C and stir vigorously. Add precipitant-Na2CO3 solution dropwise to adjust the pH to 8-10. Continue stirring the obtained mixture for 2 hours. Collect the formed precipitate, wash it to pH 7, and then dry it in a vacuum drying oven at 60°C for 12 hours to obtain unreduced Cu-ZnO / TiO2. (3) The unreduced catalyst Cu-ZnO / TiO2 is placed in a tubular furnace, heated and reduced under a hydrogen atmosphere, and naturally cooled to room temperature to obtain Cu-ZnO / TiO2.

6. The use according to claim 5, characterized in that: In the preparation step (1) of the non-precious metal catalyst Cu-ZnO / TiO2, the mass ratio of P25 type TiO2 to zinc nitrate hexahydrate is 3-14:

1.

7. The use according to claim 5, characterized in that: In the preparation step (2) of the non-precious metal catalyst Cu-ZnO / TiO2, the mass ratio of the ZnO / TiO2-P25 carrier to copper nitrate trihydrate is 2-26:

1.

8. The use according to claim 5, characterized in that: In the preparation steps (1) and (2) of the non-precious metal catalyst Cu-ZnO / TiO2, the concentration of the Na2CO3 solution is 0.1 g / mL.

9. The use according to claim 5, characterized in that: In the preparation step (1) of the non-precious metal catalyst Cu-ZnO / TiO2, the heating rate of the muffle furnace is 5°C / min, the calcination temperature is 250-450°C, and the calcination time is 3.5-4.5h.

10. The use according to claim 5, characterized in that: In the preparation step (3) of the non-precious metal catalyst Cu-ZnO / TiO2, the heating rate of the tubular furnace is 5°C / min, the reduction temperature in the tubular furnace is 200-400°C, and the reduction time is 1-3h.

Images