Preparation of Zr (OH) 4 loaded Cu bifunctional catalyst and application of Zr (OH) 4 loaded Cu bifunctional catalyst in catalytic synthesis of N-benzylaniline compound
By introducing Cu/Zr(OH)4 catalyst in the traditional synthesis of N-benzyl aniline, the problem of excessive generation of by-products caused by excessive benzyl alcohol is solved, and low-cost and efficient synthesis of N-benzyl aniline is achieved. It conforms to the principles of atomic economy and improves catalytic performance.
Patent Information
- Application Number
- CN202411307474.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2025-01-17
AI Technical Summary
Excessive amount of benzyl alcohol in the traditional synthesis of N-benzyl aniline method leads to excessive generation of by-product benzaldehyde, which violates the principle of atomic economic synthesis.
Design a heterogeneous catalytic system of benzyl alcohol and nitrobenzene based on stoichiometric ratio, use zirconium hydroxide as catalyst, and enhance catalytic activity by introducing copper-supported form to form Cu/Zr(OH)4 catalyst to achieve selection N-benzyl aniline was synthesized.
It effectively reduces the generation of by-product benzaldehyde, conforms to the atomic economic concept, provides a low-cost, efficient and green synthetic method, and improves catalytic performance and production sustainability.
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Abstract
Description
Technical Field
[0001] The present invention relates to a design strategy of a supported bifunctional catalyst and its application, in particular to using Cu / Zr(OH)4 as a catalyst for synthesizing N-benzylaniline compounds with benzyl alcohol or its derivatives and nitrobenzene or its derivatives as substrates. Technical Background
[0002] Secondary amine compounds (also known as N-alkylamines) play a key role in the production of bioactive molecules, drugs, pesticides, dyes, surfactants and many other value-added products, among which N-benzylaniline (hereinafter referred to as secondary amine) (see Journal of Catalysis, 2024, Issue 429, 115241.) is particularly important, and the market for N-alkylamines is expected to grow steadily in the next few years to meet its growing consumption.
[0003] The traditional method for synthesizing N-benzyl aniline mainly involves the hydroamination of alkynes (see Journal of the American Chemical Society, 2020, No. 142, Vol. 34, 14455-14460.), direct alkylation of amines and halogenated hydrocarbons (see Journal of the American Chemical Society, 2021, No. 143, Vol. 37, 15413-15419.) and alcohol amine condensation (see Small, 2023, No. 19, Vol. 18, 2207941.) etc. Among them, alcohol amine condensation is regarded as an ideal method because the substrate cost is low, it is easy to obtain, and the by-product is only water. In addition, it has great potential to use more primitive, cheaper and more easily available nitro compounds to replace amine compounds and another component benzyl alcohol to synthesize N-benzyl aniline.
[0004] In this reaction system, studies have used homogeneous catalysts with metals such as molybdenum, ruthenium, and iridium as active components, as well as heterogeneous catalysts with metals such as palladium, gold, titanium, and cobalt as active components. However, the amount of benzyl alcohol used in these studies is usually three times or more than that of nitrobenzene, resulting in the generation of a large amount of byproduct benzaldehyde, which does not conform to the principle of atom-economic synthesis. Therefore, we intend to design a heterogeneous catalytic system based on stoichiometric benzyl alcohol and nitrobenzene for the selective synthesis of N-benzylaniline. This system uses hydrogen as an exogenous hydrogen source, avoiding the excessive generation of benzaldehyde byproducts, which is completely in line with the concept of atom economy.
[0005] In order to realize the above reaction process, a catalyst having both hydrogenation and dehydrogenation capabilities is required. In our previous work, we found that zirconium hydroxide has both hydrogenation (see "Catalysis Science & Technology" 2024, Issue 14, Vol. 4, 1008-1016.) and dehydrogenation (see "Angewandte Chemie International Edition", 2024) bifunctionality, showing its potential as a catalytic one-pot synthesis of N-benzylaniline. The reaction process specifically includes nitrobenzene hydrogenation, benzyl alcohol dehydrogenation, coupling reaction of benzaldehyde and aniline, and N-benzylidene aniline hydrogenation. However, when zirconium hydroxide is used alone as a catalyst, the catalytic performance is limited. To this end, we introduce copper into the catalytic system in a supported form to improve the overall catalytic activity. The present invention not only effectively reduces the generation of byproduct benzaldehyde from the perspective of environmental friendliness and sustainable development, but also provides a new path for synthesizing high value-added fine chemicals from the perspective of organic synthesis. Summary of the invention
[0006] The present invention finds that a catalyst prepared by commercially purchased zirconium hydroxide loaded with copper can catalyze the one-pot coupling of benzyl alcohol and nitrobenzene in a stoichiometric ratio to generate N-benzyl aniline. Therefore, the present invention not only solves the problem of excessive benzyl alcohol in the traditional synthesis method, effectively reduces the generation of by-product benzaldehyde, but also proposes a low-cost, green and efficient method for selectively preparing N-benzyl aniline, which is simple, low-cost, and highly safe, and is more in line with the concept of green and friendly chemistry. Specifically includes the following contents:
[0007] In a first aspect, the present invention provides a method for preparing a supported catalyst Cu / Zr(OH)4 (hereinafter referred to as Cu / Zr(OH)4) by a simple precipitation deposition method using commercially available zirconium hydroxide as a catalyst carrier.
[0008] Preferably, the catalyst preparation method comprises the following steps:
[0009] (1) Treatment of zirconium hydroxide catalyst: A certain amount of commercial Zr(OH)4 was weighed and dried at 60°C, and then calcined in a muffle furnace at a heating rate of 3°C / min to 200°C for 4 h.
[0010] (2) Preparation of supported catalyst: A specific mass of treated Zr(OH)4 was weighed and dispersed in a container containing 250 mL of deionized water. Then, a certain concentration of copper nitrate aqueous solution was added. After stirring for 12 h, a 1 M sodium hydroxide solution was added until the copper ions were completely precipitated. After continuous stirring for 12 h, the solid product was separated, washed with deionized water, dried at 60 °C, and finally calcined and reduced in a hydrogen atmosphere at 200 °C for 4 h to obtain the supported catalyst Cu / Zr(OH)4.
[0011] Preferably, the raw materials are benzyl alcohol or its derivatives (I) and nitrobenzene or its derivatives (II), and the structural formula of the product N-benzylaniline or its derivatives is shown in the following formula (III), and their structural formulas are shown in the following formulas:
[0012]
[0013] Wherein, R1-R5 are independently selected from any one of hydrogen, halogen, hydroxyl, sulfonic acid, nitro, substituted or unsubstituted straight or branched alkyl, alkoxy, carbonyl, alkenyl, alkynyl, substituted or unsubstituted aryl, acylamino, and cyano, but are not limited to the above substituents.
[0014] Preferably, R1-R5 are independently selected from hydrogen, methyl, chlorine, fluorine, and methoxy.
[0015] Preferably, the benzyl alcohol or its derivatives include: benzyl alcohol, p-methylbenzyl alcohol, p-chlorobenzyl alcohol, p-fluorobenzyl alcohol, and p-methoxybenzyl alcohol.
[0016] Preferably, the nitrobenzene or its derivatives include: nitrobenzene, p-nitrotoluene, p-chloronitrobenzene, p-fluoronitrobenzene, and p-nitroanisole.
[0017] In a second aspect, the present invention provides a method for preparing N-benzylaniline or its derivatives, the method comprising: using benzyl alcohol or its derivatives (I) and nitrobenzene or its derivatives (II) as raw materials, an organic solvent as a reaction solvent, Cu / Zr(OH)4 as a catalyst, and hydrogen as a reaction atmosphere, and catalytically coupling reaction to synthesize N-benzylaniline or its derivatives (III) as shown in the following formula, wherein the organic solvent comprises n-octane, n-pentane, n-hexane, petroleum ether, N,N-dimethylformamide, ethanol, toluene, and acetonitrile.
[0018]
[0019] Among them, R1-R5 are independently selected from any one of hydrogen, halogen, hydroxyl, sulfonic acid, nitro, substituted or unsubstituted straight or branched alkyl, alkoxy, carbonyl, alkenyl, alkynyl, substituted or unsubstituted aryl, acylamino, and cyano, but are not limited to the above substituents.
[0020] Preferably, R1-R5 are independently selected from hydrogen, methyl, chlorine, fluorine, and methoxy.
[0021] Preferably, the benzyl alcohol or its derivatives include: benzyl alcohol, p-methylbenzyl alcohol, p-chlorobenzyl alcohol, p-fluorobenzyl alcohol, and p-methoxybenzyl alcohol.
[0022] Preferably, the nitrobenzene or its derivatives include: nitrobenzene, p-nitrotoluene, p-chloronitrobenzene, p-fluoronitrobenzene, and p-nitroanisole.
[0023] Preferably, the usage ratio of Cu to Zr(OH)4 is 0-50:100.
[0024] Preferably, the usage ratio of Cu to Zr(OH)4 is 10:100.
[0025] Preferably, the ratio of the catalyst to benzyl alcohol or its derivatives is 10-15 g:100 mmol.
[0026] Preferably, the ratio of the catalyst to benzyl alcohol or its derivatives is 11 g:100 mmol.
[0027] Preferably, the ratio of the reaction solvent to benzyl alcohol or its derivatives is 1000 mL:100 mmol.
[0028] Preferably, the hydrogen pressure is 0.5 MPa.
[0029] Preferably, the reaction temperature is 100-180°C.
[0030] Preferably, the reaction temperature is 180°C.
[0031] Preferably, the reaction time is 7 h.
[0032] Preferably, the reaction solvent is n-octane.
[0033] Preferably, the catalyst is Cu / Zr(OH)4.
[0034] Preferably, the method comprises the following steps:
[0035] (1) adding benzyl alcohol or its derivatives, nitrobenzene or its derivatives, and Cu / Zr(OH)4 into a high-pressure sterilization reactor containing a certain amount of reaction solvent n-octane;
[0036] (2) After the atmosphere in the reactor is completely replaced with high-pressure hydrogen, the reaction is carried out at a certain hydrogen pressure and 180°C for 7 hours;
[0037] (3) Filtration, distillation and recrystallization to obtain N-benzylaniline.
[0038] Compared with the prior art, the technical solution of the present invention has the following advantages:
[0039] (1) The present invention designs a novel bifunctional supported catalytic system that can simultaneously realize hydrogenation and dehydrogenation reactions with one catalyst;
[0040] (2) The present invention uses hydrogen as a hydrogen source and uses benzyl alcohol and nitrobenzene in a stoichiometric ratio as substrates, which greatly reduces the production of byproduct benzaldehyde and conforms to the concept of atomic economy;
[0041] (3) Nitrobenzene or its derivatives used in the present invention are more original, cheaper and easier to obtain than aniline and its derivatives commonly used in traditional industries, thus greatly reducing production costs;
[0042] (4) The method of the present invention can catalyze the coupling of benzyl alcohol or its derivatives and nitrobenzene or its derivatives to generate the corresponding secondary amines, and the yield of the target product is high. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Figure 1 X-ray diffraction crystal structures of the prepared catalysts (including Cu, Zr(OH)4, Cu / Zr(OH)4);
[0044] Figure 2 SEM images of the prepared supported catalysts;
[0045] Figure 3 Transmission electron microscope image of the prepared supported catalyst;
[0046] Figure 4 Mass spectrum of the product N-benzylaniline synthesized by the method described in Example 1;
[0047] Figure 5 Mass spectrum of the product N-benzylaniline synthesized by the method described in Example 2;
[0048] Figure 6 Mass spectrum of the product N-benzylaniline synthesized by the method described in Example 3;
[0049] Figure 7 Mass spectrum of the product N-benzylaniline synthesized by the method described in Example 4;
[0050] Figure 8 Mass spectrum of the product N-benzyl-p-methoxyaniline synthesized by the method described in Example 4;
[0051] Fig. 9 Mass spectrum of the product N-[(4-methylphenyl)methyl]aniline synthesized by the method described in Example 4;
[0052] Fig.10 Mass spectrum of the product N-(4-chlorobenzyl)aniline synthesized by the method described in Example 4;
[0053] Fig.11 Mass spectrum of the product N-benzylaniline synthesized by the method described in Example 5;
[0054] Fig.12 Mass spectrum of the product N-benzyl-4-methoxyaniline synthesized by the method described in Example 5;
[0055] Fig.13 Mass spectrum of the product N-(4-methylphenyl)-benzylamine synthesized by the method described in Example 5;
[0056] Fig.14 Mass spectrum of the product N-benzyl-4-chloroaniline synthesized by the method described in Example 5. DETAILED DESCRIPTION
[0057] The present invention is further described in detail below in conjunction with specific examples, but the protection scope of the present invention is not limited thereto. The raw materials used in the following examples are all commercially available unless otherwise specified.
[0058] Example 1 Synthesis of N-benzylaniline with different ratios of Cu and Zr(OH)4
[0059] 1. Add 10.0 g of Zr(OH)4 catalyst with a Cu to Zr(OH)4 ratio of 0:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0060] 2. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0061] 3. Add 12 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 20:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0062] 4. Add 13 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 30:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0063] 5. Add 14 mg of Cu / Zr(OH)4 catalyst with a Cu to Zr(OH)4 ratio of 40:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0064] 6. Add 15 mg of Cu / Zr(OH)4 catalyst with a Cu to Zr(OH)4 ratio of 50:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0065] The yield of N-benzylaniline obtained by the preparation method described in 1-6 above was calculated, and the results are shown in Table 1 below:
[0066] Table 1 Process parameters and product yields of the preparation method described in Example 1
[0067]
[0068] The mass spectrum of the main product synthesized by the above reaction is as follows Figure 4 As shown (the mass spectra of all the above products are the same, so only one mass spectrum is provided). The structural formula of the product is shown in Formula 1. The above results show that using n-octane as the reaction solvent and Cu / Zr(OH)4 as the catalyst (the ratio of Cu to Zr(OH)4 is 10:100, and the total catalyst amount is 11g) under the conditions of 7h, 180°C and 0.5MPa hydrogen, it can catalyze the coupling of benzyl alcohol and nitrobenzene to synthesize secondary amines with a yield of 100%.
[0069]
[0070] Example 2 Synthesis of N-benzylaniline using different reaction solvents
[0071] 1. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0072] 2. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of isopentane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0073] 3. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-hexane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0074] 4. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of petroleum ether, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0075] 5. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of N,N-dimethylformamide, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0076] 6. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of ethanol, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0077] 7. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of toluene, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0078] 8. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of acetonitrile, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0079] The product yield obtained by the preparation method described in 1-8 above was calculated, and the results are shown in Table 2 below:
[0080] Table 2 Process parameters and product yields of the preparation method described in Example 2
[0081]
[0082] The mass spectrum of the main product obtained from the above reaction is as follows Figure 5 As shown (the mass spectra of all the above products are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1. The above results show that using 1000 mL of n-octane as the reaction solvent and Cu / Zr(OH)4 as the catalyst (the ratio of Cu to Zr(OH)4 is 10:100, and the total catalyst amount is 11 g) under the conditions of 7 h, 180°C and 0.5 MPa of hydrogen, it can catalyze the coupling of benzyl alcohol and nitrobenzene to synthesize secondary amines with a yield of 100%.
[0083]
[0084] Example 3 Synthesis of N-benzylaniline at different reaction temperatures
[0085] 1. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 100 °C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0086] 2. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 110°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0087] 3. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 120°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0088] 4. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 130°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0089] 5. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 140°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0090] 6. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL high pressure sterilization reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 150°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0091] 7. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 160°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0092] 8. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 170°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0093] 9. Add 11 g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 into a 2500 mL autoclave reactor, then add 10.81 g of benzyl alcohol, 12.31 g of nitrobenzene and 1000 mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5 MPa, react at 180°C for 7 h, and then filter, distill and recrystallize to obtain the product N-benzylaniline.
[0094] The product yield obtained by the preparation method described in 1-9 above was calculated, and the results are shown in Table 3 below:
[0095] Table 3 Process parameters and product yields of the preparation method described in Example 3
[0096]
[0097] The mass spectrum of the main product obtained from the above reaction is as follows Figure 6As shown (the mass spectra of all the above products are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1. The above results show that using n-octane as the reaction solvent and Cu / Zr(OH)4 as the catalyst (the ratio of Cu to Zr(OH)4 is 10:100, and the total catalyst amount is 11g) under the conditions of 7h, 180°C and 0.5MPa hydrogen, it can catalyze the coupling of benzyl alcohol and nitrobenzene to synthesize secondary amines with a yield of 100%.
[0098]
[0099] Example 4 Synthesis of corresponding secondary amine products using different benzyl alcohol derivatives
[0100] 1. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 10.81g of benzyl alcohol, 12.31g of nitrobenzene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-benzylaniline. The mass spectrum of the product is shown in the figure below: Figure 7 As shown, the structural formula is shown in Formula 1.
[0101]
[0102] 2. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 13.82g of p-methoxybenzyl alcohol, 12.31g of nitrobenzene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-benzyl p-methoxyaniline. The mass spectrum of the product is shown in the figure below: Figure 8 As shown, the structural formula is shown in Formula 2.
[0103]
[0104] 3. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 12.22g of p-methylbenzyl alcohol, 12.31g of nitrobenzene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-[(4-methylphenyl)methyl]aniline. The mass spectrum of the product is shown in the figure below: Fig. 9 As shown, the structural formula is shown in Formula 3.
[0105]
[0106] 4. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 14.26g of p-chlorobenzyl alcohol, 12.31g of nitrobenzene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-(4-chlorobenzyl)aniline. The mass spectrum of the product is shown in the figure below: Fig.10 As shown, the structural formula is shown in Formula 4.
[0107]
[0108] The product yield obtained by the preparation method described in 1-4 above was calculated, and the results are shown in Table 4 below:
[0109] Table 4 Process parameters and product yields of the preparation method described in Example 4
[0110]
[0111] The above results indicate that using n-octane as the reaction solvent and Cu / Zr(OH)4 as the catalyst (the ratio of Cu to Zr(OH)4 is 10:100, and the total catalyst amount is 11 g) at 180°C and 0.5 MPa of hydrogen conditions can catalyze the coupling of benzyl alcohol and its derivatives with nitrobenzene to synthesize the corresponding secondary amines and their derivatives in high yield.
[0112] Example 5 Synthesis of corresponding secondary amine products using different nitrobenzene derivatives
[0113] 1. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 10.81g of benzyl alcohol, 12.31g of nitrobenzene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-benzylaniline. The mass spectrum of the product is shown in the figure below: Fig.11 As shown, the structural formula is shown in Formula 1.
[0114]
[0115] 2. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 10.81g of benzyl alcohol, 15.31g of p-nitroanisole and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-benzyl-4-methoxyaniline. The mass spectrum of the product is shown in the figure below: Fig.12 As shown, the structural formula is shown in Formula 5.
[0116]
[0117] 3. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 10.81g of benzyl alcohol, 13.71g of p-nitrotoluene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-(4-methylphenyl)-benzylamine. The mass spectrum of the product is shown in the figure below: Fig.13 As shown, the structural formula is shown in Formula 6.
[0118]
[0119] 4. Add 11g of Cu / Zr(OH)4 catalyst with a ratio of Cu to Zr(OH)4 of 10:100 to a 2500mL autoclave reactor, then add 10.81g of benzyl alcohol, 15.76g of p-chloronitrobenzene and 1000mL of n-octane, completely replace the atmosphere in the reactor with hydrogen and increase the pressure to 0.5MPa, react at 180°C for a certain period of time, filter, distill and recrystallize to obtain N-benzyl-4-chloroaniline. The mass spectrum of the product is shown in the figure below: Fig.14 As shown, the structural formula is shown in Formula 7.
[0120]
[0121] The product yield obtained by the preparation method described in 1-4 above was calculated, and the results are shown in Table 5 below:
[0122] Table 5 Process parameters and product yields of the preparation method described in Example 5
[0123]
[0124] The above results indicate that using n-octane as the reaction solvent and Cu / Zr(OH)4 as the catalyst (the ratio of Cu to Zr(OH)4 is 10:100, and the total catalyst amount is 11 g) at 180°C and 0.5 MPa of hydrogen, it is possible to catalyze the coupling of benzyl alcohol and nitrobenzene and its derivatives to synthesize the corresponding secondary amines and their derivatives in high yield.
[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.
Claims
1. A method for preparing a supported catalyst Cu / Zr(OH)4 and its application in catalyzing the coupling of benzyl alcohol or its derivatives and nitrobenzene or its derivatives in a stoichiometric ratio to synthesize N-benzylaniline or its derivatives.
2. As claimed in claim 1, the preparation method of supported catalyst Cu / Zr(OH)4 is characterized in that: Using commercial Zr(OH)4 as the catalyst carrier, metal Cu was introduced into the catalyst system in the form of loading. The specific operation steps are as follows: Step 1, treatment of Zr(OH)4: weigh a specific mass of commercial Zr(OH)4 and dry and calcine it at a specific temperature. Step 2, preparation of supported catalyst: weigh a specific mass of treated Zr(OH)4, disperse it in a container containing a certain amount of deionized water, then add a certain concentration of copper nitrate aqueous solution, stir for a certain period of time, add a precipitant, and continue stirring for several hours, then separate the solid product, wash, dry, calcine and reduce it to obtain the supported catalyst Cu / Zr(OH)4.
3. The method for preparing a catalyst according to claims 1 and 2, characterized in that: The drying temperature in step 1 is 40-80°C, and the drying time is 2-20h. The precipitant in step 2 is a 1M sodium hydroxide solution, and the stirring time is 2-20h. The reducing atmosphere is hydrogen, the reducing temperature is 180-250°C, the roasting time is 2-20h, and the heating rate is 1-20°C / min. The mass ratio of Cu to Zr(OH)4 in step 2 is 0-50:
100.
4. The use of the method of claim 1 for synthesizing N-benzylaniline or its derivatives by coupling benzyl alcohol or its derivatives and nitrobenzene or its derivatives in a stoichiometric ratio, characterized in that: The structural formula of the N-benzylaniline or its derivative is shown in the following formula (III), and the raw materials are benzyl alcohol or its derivative (I) and nitrobenzene or its derivative (II), and their structural formulas are shown in the following formulas: Wherein, R1-R5 are independently selected from any one of hydrogen, halogen, hydroxyl, sulfonic acid, nitro, substituted or unsubstituted straight or branched alkyl, alkoxy, carbonyl, alkenyl, alkynyl, substituted or unsubstituted aryl, acylamino, and cyano, but are not limited to the above substituents.
5. A method for preparing N-benzylaniline or its derivatives as claimed in claims 1 and 4, comprising: Benzyl alcohol or its derivative (Ⅰ) and nitrobenzene or its derivative (Ⅱ) shown in the following formula are used as raw materials, an organic solvent is used as a reaction solvent, Cu / Zr(OH)4 is used as a catalyst, and hydrogen is used as a reaction atmosphere to synthesize N-benzylaniline or its derivative (Ⅲ) shown in the following formula through a catalytic coupling reaction, wherein the organic solvent includes n-octane, isopentane, n-pentane, n-heptane, cyclohexane, n-hexane, petroleum ether, N,N-dimethylformamide, ethanol, methanol, water, toluene, and acetonitrile; Among them, R1-R5 are independently selected from any one of hydrogen, halogen, hydroxyl, sulfonic acid, nitro, substituted or unsubstituted straight or branched alkyl, alkoxy, carbonyl, alkenyl, alkynyl, substituted or unsubstituted aryl, acylamino, and cyano.
6. The synthesis method according to claims 1, 4 and 5, characterized in that: The ratio of Cu to Zr(OH)4 in the catalyst is 0-50:100, the ratio of the catalyst to benzyl alcohol is 10-15 g:100 mmol, the hydrogen pressure is 0.5 MPa, the ratio of the reaction solvent to benzyl alcohol is 1000 mL:100 mmol, the reaction temperature is 100-180°C, and the reaction time is 7 hours.
7. The synthesis method according to claim 4-5, characterized in that: The R1-R5 are selected from hydrogen, methyl, chlorine, fluorine and methoxy. The benzyl alcohol or its derivatives and nitrobenzene or its derivatives include benzyl alcohol, p-methylbenzyl alcohol, p-methoxybenzyl alcohol, 4-fluorobenzyl alcohol, 4-chlorobenzyl alcohol, nitrobenzene, p-nitrotoluene, p-nitrobenzene anisole, 4-fluoronitrobenzene and 4-chloronitrobenzene.
8. The synthesis method according to any one of claims 4 to 7, characterized in that: Benzyl alcohol or its derivatives, nitrobenzene or its derivatives, Cu / Zr(OH)4 (wherein the ratio of Cu to Zr(OH)4 is 10:100, and the ratio of catalyst to substrate is 11 g:100 mmol) are added to n-octane (with the ratio of benzyl alcohol being 1000 mL:100 mmol), and the mixture is reacted at a hydrogen pressure of 0.5 MPa and 180°C for 7 h; N-benzylaniline or its derivatives are obtained by filtration, distillation and recrystallization.