Application of non-noble metal catalyst Cu-ZnO / TiO2-P25 in catalytic synthesis of N, N'-dicyclohexyl-p-phenylenediamine in heterogeneous system

Abstract

The application relates to a non-noble metal catalyst Cu-ZnO / TiO2 in a heterogeneous system for catalytically synthesizing N,N' The application belongs to the technical field of catalyst preparation and application, and relates to application of dicyclohexyl-p-phenylenediamine. The catalyst takes zinc nitrate hexahydrate as a zinc source, copper nitrate trihydrate as a copper source, and P25 type titanium dioxide as a carrier. The catalyst is obtained by loading the metal on the titanium dioxide through a step-by-step precipitation method, reducing the catalyst Cu-ZnO / TiO2 in a tube furnace through hydrogen, and then dispersing the catalyst in a solvent to catalyze the photo-thermal reduction amination reaction of p-phenylenediamine and cyclohexanone to synthesize a novel rubber antioxidant N,N' dicyclohexyl-p-phenylenediamine. The Cu-ZnO / TiO2 catalyst with copper and zinc oxide contents of 7% and 4% respectively has excellent catalytic performance. When the hydrogen pressure is 6 MPa, the temperature is 200 DEG C, and the reaction time is 10 h, the conversion rate of p-phenylenediamine reaches 100%, N,N' N,N' N,N' N,N' N,N and the selectivity of dicyclohexyl-p-phenylenediamine reaches 99.9%. The preparation method is simple, low in cost, high in catalytic selectivity, and has wide industrialization prospects.

Description

TECHNICAL FIELD

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

[0002] During long-term storage and use, rubber and its products are affected by heat, oxygen, ozone, metal ions, mechanical stress, light, high-energy radiation, and other chemical substances and mold, resulting in a decrease in physical and mechanical properties and elasticity, which is known as 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 known as antioxidants. Rubber antioxidants are an important rubber additive and play 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. N -(1,3-dimethylbutyl)- N' p-phenyl-p-phenylenediamine (6PPD) is a superior anti-ozone agent and antioxidant, and is particularly outstanding in terms of protection against fatigue and ozone cracking. However, recent research has found that 6PPD is converted into 6PPD-quinone (6PPDQ) when exposed to sunlight and air, and enters rivers, causing poisoning and even death of salmon and other aquatic wildlife, and threatening human health. Therefore, there is an urgent need to develop a new environmentally friendly and non-toxic rubber antioxidant.

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

[0004] The above reaction systems all belong to thermal catalytic systems, and have problems of harsh reaction conditions and high energy consumption. Compared with thermal catalysis, photo-thermal catalysis is a new technology integrating photocatalysis and thermal catalysis, which can reduce the reaction energy barrier, make the reaction conditions more mild, promote the mass transfer and diffusion of reaction species and photo-generated carriers, accelerate their migration to the catalyst surface interface and participate in the reaction, thereby increasing the reaction rate, regulating the catalytic reaction path and product selectivity. O. Wenger et al. first reported that ketone amine reductive amination to prepare secondary amine was realized under mild conditions by using [Ru(bpy)3]Cl2 photosensitizer through photo-redox reaction under 470 nm blue light. II Photo-excitation promotes the reduction of imine cation to electron-rich α-aminoalkyl radical intermediates, which are rapidly transferred and hydrogenated by H atoms on the thiol group to generate secondary amine. However, there is no report on the preparation of environmentally friendly rubber antioxidant by heterogeneous photo-thermal catalytic reductive amination.

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

[0006] In view of the above problems existing in the existing catalytic synthesis of CCPD, the purpose of the present application is to provide a non-noble metal catalyst Cu-ZnO / TiO2 for catalytic synthesis of N,N' dicyclohexyl-p-phenylenediamine in a heterogeneous system.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows.

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

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

[0010] N,N' - dicyclohexyl-p-phenylenediamine, in the text replaced by the abbreviation CCPD, having the same meaning.

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

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

[0013] In the Cu-ZnO / TiO2 catalyst, the method of loading of Cu and ZnO is directly abbreviated as 1-9% and 2-8% in the subsequent content of this article, which has the same meaning as 1-9wt% and 2-8wt% recorded in this article.

[0014] The preparation steps of the above-mentioned non-noble metal catalyst Cu-ZnO / TiO2 are as follows:

[0015] (1) P25 type TiO2 and zinc nitrate hexahydrate are added to pure water and stirred uniformly to obtain a suspension, which is placed in a 60-80℃ water bath, stirred vigorously, and a precipitating agent-Na2CO3 solution is added dropwise to adjust the pH to 10-12. The obtained mixture is continuously stirred for 0.5h, the formed precipitate is collected, washed to pH 7, and the obtained sample is placed in a 60℃ vacuum drying oven for drying for 12h, and calcined in a muffle furnace in an air atmosphere to obtain a ZnO / TiO2 carrier;

[0016] (2) The ZnO / TiO2 carrier and copper nitrate trihydrate are added to pure water and stirred uniformly, the obtained suspension is placed in a 50-70℃ water bath, stirred vigorously, and a precipitating agent-Na2CO3 solution is added dropwise to adjust the pH to 8-10. The obtained mixture is continuously stirred for 2h, the formed precipitate is collected, washed to pH 7, and then placed in a 60℃ vacuum drying oven for drying for 12h to obtain an unreduced Cu-ZnO / TiO2;

[0017] (3) The unreduced catalyst Cu-ZnO / TiO2 is placed in a tube furnace and heated for reduction under a hydrogen atmosphere, and naturally cooled to room temperature to obtain Cu-ZnO / TiO2.

[0018] In the above preparation method, zinc sulfate or zinc chloride can also be used in place of zinc nitrate hexahydrate in step (1), and copper sulfate or copper chloride can also be used in place of copper nitrate trihydrate in step (2), which has the same technical effect.

[0019] Preferably, the molar ratio of P25 type TiO2 to zinc nitrate hexahydrate in step (1) is 3-14:1.

[0020] Preferably, the mass ratio of the ZnO / TiO2 carrier to copper nitrate trihydrate in step (2) is 2-26:1.

[0021] Preferably, the concentration of the Na2CO3 solution in steps (1) and (2) is 0.1 g / mL.

[0022] Preferably, in step (1), the heating rate of the muffle furnace is 5 ℃ / min, the calcination temperature is 250-450 ℃, and the calcination time is 3.5-4.5 h. Since the calcination of the carrier is to obtain a carrier with a stable structure, it is necessary to control a reasonable calcination temperature and time.

[0023] Preferably, in step (2), the heating rate of the tube furnace is 5 ℃ / min, the reduction temperature in the tube furnace is 200-400 ℃, and the reduction time is 1-3 h.

[0024] The non-noble metal catalyst Cu-ZnO / TiO2 of the present application is used to catalyze the synthesis of p-phenylenediamine in a heterogeneous system. N,N' The specific steps of the synthesis of p-phenylenediamine are as follows:

[0025] (1) A stainless steel high-pressure photo-thermal reaction kettle is selected, and a glass container is inserted as the inner lining of the reaction kettle;

[0026] (2) The catalyst Cu-ZnO / TiO2 is weighed into the high-pressure photo-thermal reaction kettle, and p-phenylenediamine and cyclohexanone are weighed and dissolved in cyclohexane solvent, and the mixture is placed in the high-pressure photo-thermal reaction kettle after ultrasonic dispersion;

[0027] (3) After sealing the reaction kettle, the hydrogen gas with a pressure of 1 MPa is evacuated three times, the hydrogen pressure is maintained at 1 MPa at room temperature, and the gas tightness of the reaction kettle is checked;

[0028] (4) The reaction kettle is first heated to 200 ℃, and under the condition of 300 W full-spectrum light, hydrogen is continuously introduced to 6 MPa, and the temperature and pressure in the reaction kettle are maintained for 1 h;

[0029] (5) After the reaction is completed, the gas valve of the high-pressure photo-thermal reaction kettle is opened after cooling to room temperature, and the gas in the kettle is released until the pressure is 0, and the reaction process is completed.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] The Cu-ZnO / TiO2 prepared by the deposition-precipitation method of the present application uses non-noble metals as the active phase and P25 type TiO2 as the carrier, greatly reducing the cost of raw materials, and the preparation method is simple, green and environmentally friendly, and has industrialization prospects;

[0032] The 7%Cu-4%ZnO / P25 catalyst prepared by the preparation method has excellent catalytic performance; under the reaction conditions of hydrogen pressure 6 MPa, temperature 200 ℃, 300 W full-spectrum light, reaction time 10 h and catalyst 0.2 g, the conversion rate of 0.108 g of p-phenylenediamine is 100%, and the CCPD selectivity is 99.9%. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 XRD pattern of the Cu-ZnO / TiO2 catalyst prepared for Example 2.

[0034] Figure 2 Time-course pattern of the Cu-ZnO / TiO2 catalyst prepared for Example 2.

[0035] Figure 3 Performance pattern of the stability experiment of the Cu-ZnO / TiO2 catalyst prepared for Example 2.

[0036] Figure 4 TEM pattern of the Cu-ZnO / TiO2 catalyst prepared for Example 2. DETAILED DESCRIPTION

[0037] The technical solutions of the present application are further described below with specific examples, but the protection scope of the present application is not limited thereto.

[0038] In the present application, Cu and ZnO in different proportions are loaded on P25 type TiO2 to prepare Cu-ZnO / TiO2 as examples to detect the performance and parameters of the products and determine the optimal performance of the products.

[0039] In the following specific examples 1-10, the catalyst is prepared by using the following steps:

[0040] (1) P25 type TiO2 and zinc nitrate hexahydrate are added to pure water and stirred uniformly to obtain a suspension, which is placed in a 70 ℃ water bath, and a precipitant-Na2CO3 solution with a concentration of 0.1 g / mL is added dropwise to adjust the pH to 11, and the obtained mixture is continuously stirred for 0.5 h, the formed precipitate is collected and washed to a pH value of 7, and the obtained sample is placed in a 60 ℃ vacuum drying box for drying for 12 h, and then placed in a muffle furnace in an air atmosphere, and the muffle furnace is heated to 350 ℃ at a heating rate of 5 ℃ / min, and the calcination time is 3 h, to obtain a ZnO / TiO2 carrier;

[0041] (2) The ZnO / TiO2 carrier and copper nitrate trihydrate were added into pure water and stirred until uniform. The obtained suspension was placed into 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 obtained mixture was continuously stirred for 2 h. The formed precipitate was collected, washed until the pH was 7, and then placed into a vacuum drying oven at 60°C for drying for 12 h to obtain unreduced Cu-ZnO / TiO2.

[0042] (3) The unreduced catalyst Cu-ZnO / TiO2 was placed into a tube furnace and heated for reduction under a hydrogen atmosphere for 2 h. The temperature was increased to 300°C at a rate of 5°C / min, and the reduction time was 2 h. The temperature was naturally cooled to room temperature to obtain Cu-ZnO / TiO2.

[0043] In the raw material usage, 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 carrier to copper nitrate trihydrate to be 2-26:1, Cu and ZnO can be loaded in the catalyst in different proportions.

[0044] The catalyst prepared by the above method was tested for photocatalytic and thermal reduction of amine synthesis of CCPD as follows: The test was performed in a 200 mL stainless steel high-pressure photothermal reactor, and a glass container was inserted as the inner liner of the reactor; 0.2 g of the catalyst was weighed into the high-pressure photothermal reactor, and 0.108 g of p-phenylenediamine, 0.196 g of cyclohexanone, and 20 mL of cyclohexane were weighed, and the p-phenylenediamine and cyclohexanone were dissolved in the cyclohexane and ultrasonically dispersed uniformly, and then the mixture was placed in the high-pressure photothermal reactor. After sealing the reactor, hydrogen (1 MPa) was used to evacuate three times, and the hydrogen pressure was increased to 1 MPa at room temperature, and the airtightness was checked. After checking the airtightness, the rotation speed of the magnetic son was adjusted to 550 rpm, the temperature of the reactor was increased to 200°C, a 300 W full-spectrum xenon lamp was turned on, hydrogen was introduced until the pressure reached 6 MPa, and the timing started. After 1 h of reaction, the reactor was cooled to room temperature, the gas valve of the high-pressure photothermal reactor was opened, and the gas in the reactor was released until the pressure was 0 MPa.

[0045] The reaction solution was filtered, and 0.4 μL was injected into the gas chromatograph using a micro-liquid feeding needle. 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 column oven initial temperature was set to 150°C for 10 min, and then increased to 280°C at a rate of 25°C / min for 20 min, and the FID temperature was set to 280.0°C. With n-dodecane as an internal standard, the conversion rate and selectivity of the catalysts of different examples for the photocatalytic and thermal reduction of amine synthesis of CCPD from p-phenylenediamine and cyclohexanone were calculated by gas chromatography.

[0046] Example 1: Application of 7%Cu-2%ZnO / TiO2 in catalytic photothermal reduction amination synthesis of CCPD

[0047] The catalyst of Example 1 of the present application was tested for application in catalytic photothermal reduction amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0048] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst was 100%, and the CCPD selectivity was 73.7%.

[0049] Example 2: Application of 7%Cu-4%ZnO / TiO2 in catalytic photothermal reduction amination synthesis of CCPD

[0050] The catalyst of Example 2 of the present application was tested for application in catalytic photothermal reduction amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0051] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst was 100%, and the CCPD selectivity was 77.2%.

[0052] Example 3: Application of 7%Cu-6%ZnO / TiO2 in catalytic photothermal reduction amination synthesis of CCPD

[0053] The catalyst of Example 3 of the present application was tested for application in catalytic photothermal reduction amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0054] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst was 100%, and the CCPD selectivity was 74.6%.

[0055] Example 4: Application of 7%Cu-8%ZnO / TiO2 in catalytic photothermal reduction amination synthesis of CCPD

[0056] The catalyst of Example 4 of the present application was tested for application in catalytic photothermal reduction amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0057] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 72.1%.

[0058] Example 5: Application of 7%Cu-4%ZnO / TiO2 in catalytic photothermal reductive amination synthesis of CCPD

[0059] The catalyst of Example 5 of the present application was tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0060] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 10h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 99.9%.

[0061] Comparative Example 1: Application of 7%Cu / ZnO in catalytic photothermal reductive amination synthesis of CCPD

[0062] The 7%Cu / ZnO of Comparative Example 1 was tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0063] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 21.3%.

[0064] Comparative Example 2: Application of 7%Cu / TiO2 in catalytic photothermal reductive amination synthesis of CCPD

[0065] The 7%Cu / TiO2 of Comparative Example 2 was tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0066] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 55.5%.

[0067] Example 6: Application of 1%Cu-4%ZnO / TiO2 in catalytic photothermal reductive amination synthesis of CCPD

[0068] The catalyst of Example 6 of the present application was tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0069] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 69.2%.

[0070] Example 7: Application of 9%Cu-4%ZnO / TiO2 in catalytic photothermal reductive amination synthesis of CCPD

[0071] The catalyst of the embodiment 7 of the application is tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0072] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 72.8%.

[0073] Example 8: Application of 7%Cu-4%ZnO / TiO2 in catalytic photothermal reductive amination synthesis of CCPD

[0074] The catalyst of the embodiment 8 of the application is prepared by reduction at a hydrogen reduction temperature of 400℃, and then tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0075] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 73.8%.

[0076] Example 9: Application of 7%Cu-4%ZnO / TiO2 in catalytic photothermal reductive amination synthesis of CCPD

[0077] The catalyst of the embodiment 9 of the application is prepared by reduction at a hydrogen reduction temperature of 200℃, and then tested for application in catalytic photothermal reductive amination synthesis of CCPD, and the performance test conditions and results are as follows:

[0078] Under the reaction conditions of hydrogen pressure 6 MPa, temperature 200℃, 300W full spectrum light, reaction time 1h, catalyst 0.2g, p-phenylenediamine 0.108g and cyclohexanone 0.198g, the conversion rate of the catalyst is 100%, and the selectivity of CCPD is 70.4%.

[0079] Example 10: Application of 7%Cu-4%ZnO / TiO2 in catalytic synthesis of CCPD

[0080] The catalyst of the embodiment 10 of the application was tested for catalyzing synthesis of CCPD under lightless condition, and the performance test conditions and results are as follows:

[0081] Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 200 DEG C, reaction time of 1 h, catalyst of 0.2 g, p-phenylenediamine of 0.108 g and cyclohexanone of 0.198 g, the conversion rate of the catalyst was 100%, and the CCPD selectivity was 32.6%.

[0082] Embodiment 11: Application of 7%Cu-4%ZnO / TiO2 in catalyzing synthesis of CCPD

[0083] The catalyst of the embodiment 11 of the application was tested for catalyzing synthesis of CCPD under room temperature light condition, and the performance test conditions and results are as follows:

[0084] Under the reaction conditions of hydrogen pressure of 6 MPa, temperature of 20 DEG C, 300 W full spectrum light, reaction time of 1 h, catalyst of 0.2 g, p-phenylenediamine of 0.108 g and cyclohexanone of 0.198 g, the conversion rate of the catalyst was 0%.

[0085] The catalyst prepared in the embodiment 2 was tested for atlas, electron microscope scanning, catalytic activity and stability, and the test results are as follows.

[0086] Figure 1 The XRD atlas of the catalyst prepared in the embodiment 2 before and after catalytic reaction is shown. It can be observed that the characteristic peaks of P25 type TiO2 are obvious, and the characteristic peaks of (100), (002) and (101) crystal planes of ZnO and the characteristic peak of Cu (111) crystal plane can be observed in the atlas. The XRD atlas of the catalyst prepared in the embodiment 2 before and after catalytic reaction has little change, and the size of Cu particles in the catalyst before and after reaction is 5 nm, which indicates that the catalyst has stable structure and is a recyclable heterogeneous catalyst.

[0087] Figure 2 The Time-course atlas of the catalyst prepared in the embodiment 2 is shown. It can be seen from the atlas that the conversion rate of p-phenylenediamine is 100% at the reaction time of 0 h, 1 h, 2 h, 4 h, 8 h and 10 h, and the selectivity of CCPD is 65.0%, 77.2%, 86.2%, 92.1%, 98.5% and 99.9% respectively, which indicates that the catalyst prepared in the embodiment 2 has high catalytic activity and selectivity.

[0088] Figure 3The stability experiment performance chart of the catalyst prepared in Example 2 is shown in the figure, and it can be seen from the figure that the conversion rate of p-phenylenediamine is 100%, and the selectivity of CCPD is 77.2%, 76.4%, 77.5% and 77.8% respectively when the catalyst is cycled for the first time, the second time, the third time and the fourth time, and it can be concluded that the catalyst has high stability.

[0089] Figure 4 The TEM chart of the catalyst prepared in Example 2 is shown in the figure, and it can be seen from the figure that Cu and ZnO are loaded on P25 type TiO2, and the particle size of Cu is 5nm.

[0090] The catalytic performance of the catalyst products obtained under different conditions on p-phenylenediamine under the same reaction conditions is shown in Table 1.

[0091] Table 1: Effect of different loadings on catalytic activity

[0092]

[0093] As can be seen from Examples 1-4 in Table 1, the loading amount of ZnO has a great influence on the activity of the catalyst, when the loading amount content is from 2% to 8%, the conversion rate of p-phenylenediamine is maintained at 100%, and the selectivity of CCPD first increases and then decreases, which also means that the catalytic performance of the catalyst first increases and then decreases, showing a volcanic trend, and when the loading amount is 4%, the conversion rate is 100% and the selectivity is highest, reaching 77.2%.

[0094] As can be seen from Examples 2 and 5, when the loading amount of Cu is 7% and the loading amount of ZnO is 4%, the reaction time is extended to 10h, the conversion rate of p-phenylenediamine is maintained at 100%, and the selectivity of CCPD is increased to 99.9%.

[0095] As can be seen from Examples 2, 6 and 7, the loading amount of Cu still has a great influence on the activity of the catalyst, when the loading amount is from 1% to 9%, the conversion rate of p-phenylenediamine is maintained at 100%, and the selectivity of CCPD first increases and then decreases, and when the loading amount is 7%, the conversion rate is 100% and the selectivity is highest, reaching 77.2%.

[0096] 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.

[0097] 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, and with the increase of the reduction temperature from 200℃ to 400℃, the catalytic performance of the catalyst first increases and then decreases, and when the reduction temperature is 300℃, the catalytic performance of the catalyst reaches the highest.

[0098] As can be seen from Examples 2, 10 and 11, the photo-thermal catalysis can significantly improve the catalytic performance of the catalyst, and the reaction performance of the thermal catalysis and the photo-catalysis is lower than that of the photo-thermal catalysis. Under the reaction temperature of 200℃ and the full spectrum light of 300W, the conversion rate of the catalyst is 100%, and the CCPD selectivity is 77.2%.

[0099] The above merely describes some embodiments of the present application, and is not intended to limit the present application. Any changes and modifications made according to the content of the present application are within the protection scope of the present application.

Claims

1. Photothermo catalytic synthesis in a heterogeneous system with a non-noble metal catalyst Cu-ZnO / TiO2 N,N' - the use of dicyclohexyl-p-phenylenediamine, characterized in that In the presence of Cu-ZnO / TiO2 catalyst, p-phenylenediamine and cyclohexanone as reactants, cyclohexane as solvent, under hydrogen atmosphere and full spectrum light, the catalytic reaction generates N,N' - dicyclohexyl-p-phenylenediamine; The non-noble metal catalyst Cu-ZnO / TiO2, wherein Cu and ZnO are loaded on P25 type TiO2, the loading amount of Cu is 1-9wt% of the catalyst, and the loading amount of ZnO is 2-8wt% of the catalyst.

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

3. Use according to claim 1, characterized in that, In the non-noble metal catalyst Cu-ZnO / TiO2, the loading amount of Cu is 7wt% of the catalyst, and the loading amount of ZnO is 4wt% of the catalyst.

4. Use according to claim 1, characterized in that, The preparation steps of the non-noble metal catalyst Cu-ZnO / TiO2 are as follows: (1) P25 type TiO2 and zinc nitrate hexahydrate are added into pure water and stirred uniformly to obtain a suspension, which is placed into a water bath at 60-80℃ and stirred vigorously, and a precipitant-Na2CO3 solution is added dropwise to adjust pH to 10-12, and the obtained mixture is continuously stirred for 0.5h, and the formed precipitate is collected and washed until pH is 7, and the obtained sample is placed into a vacuum drying box at 60℃ and dried for 12h, and calcined in a muffle furnace in an air atmosphere to obtain a ZnO / TiO2 carrier; (2) the ZnO / TiO2 carrier and copper nitrate trihydrate are added into pure water and stirred uniformly, and the obtained suspension is placed into a water bath at 50-70℃ and stirred vigorously, and a precipitant-Na2CO3 solution is added dropwise to adjust pH to 8-10, and the obtained mixture is continuously stirred for 2h, and the formed precipitate is collected and washed until pH is 7, and then placed into a vacuum drying box at 60℃ and dried for 12h to obtain unreduced Cu-ZnO / TiO2; (3) the unreduced catalyst Cu-ZnO / TiO2 is placed into a tube furnace and heated and reduced under a hydrogen atmosphere, and naturally cooled to room temperature to obtain Cu-ZnO / TiO2.

5. Use according to claim 4, characterized in that, In the preparation step (1) of the non-noble metal catalyst Cu-ZnO / TiO2, the mass ratio of P25 type TiO2 to zinc nitrate hexahydrate is 3-14:

1.

6. Use according to claim 4, characterized in that, In the preparation step (2) of the non-noble metal catalyst Cu-ZnO / TiO2, the mass ratio of the ZnO / TiO2-P25 carrier to copper nitrate trihydrate is 2-26:

1.

7. Use according to claim 4, characterized in that, In the preparation steps (1) and (2) of the non-noble metal catalyst Cu-ZnO / TiO2, the concentration of the Na2CO3 solution is 0.1g / mL.

8. Use according to claim 4, characterized in that, In the preparation step (1) of the non-noble metal catalyst Cu-ZnO / TiO2, the heating rate of the muffle furnace is 5℃ / min, the calcination temperature is 250-450℃, and the calcination time is 3.5-4.5h.

9. Use according to claim 4, characterized in that, In the preparation step (3) of the non-noble metal catalyst Cu-ZnO / TiO2, the heating rate of the tube furnace is 5℃ / min, the reduction temperature in the tube furnace is 200-400℃, and the reduction time is 1-3h.

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