Preparation method of uranium-depleted uranium-based catalyst UO4·2H2O and its application in the catalytic synthesis of azobenzene or its derivatives

Abstract

The wisdom utilization of nuclear energy plays a core and irreplaceable role in consolidating national defense security and transforming energy system to green. While the nuclear energy technology is booming, how to properly manage and efficiently resource the depleted uranium (especially 238 U, although it does not constitute direct radioactive hazard to human body) generated in the process of nuclear energy application has become an urgent and key technical challenge in the field of environmental protection and sustainable development. In particular, we use U3O8 prepared from depleted UF6 as raw material, and use UO4·2H2O prepared by simple dissolution and precipitation as catalyst to catalyze the synthesis of diphenyldiazene or its derivatives from aniline: one aspect of the invention creates a way to reuse depleted uranium waste, finding a new way to transform this traditionally difficult waste, and on the other hand, it ingeniously builds a bridge from aniline and its derivatives to high value-added chemicals-diphenyldiazene or its derivatives. Not only can it effectively reduce the potential threat of depleted uranium waste to the environment, realize the green transformation and resource utilization of waste, but also can promote the chemical industry to a more efficient and environmentally friendly direction, and bring significant economic benefits to the chemical industry.

Description

Technical Field

[0001] This invention relates to a novel technology for the utilization of depleted uranium, particularly the preparation of UO4·2H2O from depleted UF6 as a raw material for the selective catalytic oxidation of aniline or its derivatives to prepare diphenyldiazene or its derivatives. Technical Background

[0002] In the nuclear fuel production process, isotope mass separation technology is widely used to enrich natural uranium. This process inevitably produces a large amount of depleted uranium as a byproduct, the problem of which dates back to the 1940s (see *Angewandte Chemie International Edition*, 2006, Vol. 46, No. 10, pp. 1562-1563). Currently, approximately 95% of depleted uranium is stored as uranium fluoride (VI), or uranium hexafluoride. However, this form has not found widespread commercial application, leading to a continuous increase in global uranium hexafluoride stockpiles, becoming a pressing environmental and economic challenge. Given this situation, how to effectively utilize these dumped uranium hexafluoride stockpiles has become one of the major issues facing the nuclear power industry. Therefore, from the perspective of economic efficiency and environmental sustainability, actively promoting the effective utilization of depleted uranium, rather than simply storing it, is undoubtedly a more reasonable and urgent choice.

[0003] Uranium is a unique chemical element. Its large radius, the coordination number resulting from the participation of f orbitals in bonding interactions, and its unique coordination structure distinguish it from transition metals. Its chemical reactivity is complementary to that of d-block transition elements, thus uranium-based catalysts exhibit great catalytic potential. Meanwhile, the wide range of uranium oxidation states and numerous thermodynamically stable and metastable phase modifications in the uranium-oxygen system (see *Journal of Nuclear Materials*, 1995, Vol. 223, No. 3, pp. 231-237) imply the effective application of uranium oxide as a component of oxidation process catalysts. In recent years, research on uranium oxides has been continuously increasing (see *Nature*, 2012, Vol. 335, No. 6073, pp. 1184-1187), mainly involving uranium-containing oxides such as UO2, U3O8, and UO3. H. Idriss et al. synthesized 4-methyl-1,3-pentadiene via aldol condensation of acetone dimers using uranium dioxide (see *Surface Science*, 2007, Vol. 601, 5690-5700). SV Chong et al. used UO2 to convert ethanol into high-value-added ethylene (see *Surface Science*, 2000, Vol. 444, No. 1, 187-198).

[0004] Diphenyldiazene or its derivatives are important, high-value fine chemicals widely used in organic dyes, chemical indicators, food preservatives, additives, free radical reaction initiators, polymers, and pharmaceuticals. Furthermore, they can serve as precursors in the synthesis of complex natural products. They have broad market prospects and demand.

[0005] Given the unique characteristics of uranium oxides—a wide range of uranium oxidation states and numerous thermodynamically stable and metastable phases within the uranium-oxygen system—their catalytic oxidation capabilities are significantly enhanced. Furthermore, the nuclear industry currently faces the critical challenge of depleted uranium storage and utilization. Therefore, this paper considers designing a uranium-based catalyst prepared from depleted uranium waste. This catalyst aims to promote the catalytic oxidation of aniline and its derivatives, leveraging its unique catalytic properties to facilitate the synthesis of high-value diphenyldiazene or its derivatives. Such a method has not yet been reported.

[0006] In summary, we have developed a novel uranium-based heterogeneous catalyst, UO4·2H2O, and for the first time applied it to the field of thermocatalysis to achieve the efficient synthesis of fine chemicals. The catalyst is simple to prepare, using U3O8 obtained from depleted UF6 as a raw material, and can be prepared simply through a solvent-reprecipitation method. More importantly, the method of directly catalyzing the synthesis of diphenyldiazepine or its derivatives from aniline using UO4·2H2O has not been reported to date. Summary of the Invention

[0007] This invention discovers that a UO4·2H2O catalyst prepared using U3O8 obtained from depleted UF6 as a raw material can catalytically oxidize aniline or its derivatives to form diphenyldiazene or its derivatives. Therefore, this invention not only provides a novel method for utilizing depleted uranium, but also proposes a low-cost, green, and efficient method for preparing diphenyldiazene or its derivatives. This method is simple, low-cost, and highly safe, aligning well with green and friendly chemistry principles. Specifically, it includes the following:

[0008] In a first aspect, the present invention provides a method for preparing a UO4·2H2O catalyst by simply dissolving and reprecipitating U3O8 obtained from depleted UF6 as a raw material.

[0009] Preferably, the catalyst preparation method includes the following steps:

[0010] (1) Preparation of UO4·2H2O: Weigh a specific mass of U3O8 prepared from depleted UF6 as raw material, place it in a container, and while heating and stirring, add an appropriate amount of concentrated nitric acid or concentrated hydrochloric acid to completely dissolve U3O8. Then add an appropriate amount of deionized water to form a transparent uranyl salt solution, and then add an appropriate amount of hydrogen peroxide. After stirring continuously for several hours, separate the solid product, wash and dry it to obtain UO4·2H2O. Its XRD crystal structure is shown in the attached figure.Figure 1 As shown, its transmission electron microscope (TEM) image is attached. Figure 2 As shown, its scanning electron microscope image is attached. Figure 3 As shown in the attached figure, its nitrogen isothermal adsorption curve is as follows. Figure 4 As shown.

[0011] Preferably, the aniline or its derivative has the structural formula shown in formula (I) below, and the diphenyldiazene or its derivative has the structural formula shown in formula (II) below.

[0012]

[0013] R1-R5 are selected from any one of hydrogen, methyl, chlorine, bromine, and methoxy groups, but are not limited to the above substituents.

[0014] Preferably, the aniline or its derivatives include: aniline, o-methylaniline, m-methylaniline, p-methylaniline, p-chloroaniline, p-bromoaniline, and p-methoxyaniline.

[0015] Preferably, the catalyst is UO4·2H2O.

[0016] Preferably, the ratio of the catalyst to aniline or its derivative is 1-50 mg : 1 mol.

[0017] Preferably, the ratio of the catalyst to aniline or its derivative is 10-40 mg : 1 mol.

[0018] Preferably, the ratio of the catalyst to aniline or its derivative is 30 mg : 1 mol.

[0019] Preferably, the molar ratio of the tert-butyl hydroperoxide to aniline or its derivative is 1-14:1.

[0020] Preferably, the molar ratio of the tert-butyl hydroperoxide to aniline or its derivative is 2-8:1.

[0021] Preferably, the molar ratio of the tert-butyl hydroperoxide to aniline or its derivative is 7:1.

[0022] Preferably, the mass ratio of the reaction solvent to aniline or its derivative is 1-67:1.

[0023] Preferably, the mass ratio of the reaction solvent to aniline or its derivative is 10-50:1.

[0024] Preferably, the mass ratio of the reaction solvent to aniline or its derivative is 33:1.

[0025] Preferably, the method includes: adding aniline or its derivative, UO4·2H2O, and tert-butyl hydrogen peroxide to a reaction solvent, reacting at 30-120 °C for 1-16 h; filtering, distilling, and recrystallizing to obtain diphenyldiazene or its derivative. Preferably, the reaction temperature is 60-100 °C.

[0026] Preferably, the reaction temperature is 30-120 °C.

[0027] Preferably, the reaction temperature is 60-100 °C.

[0028] Preferably, the reaction temperature is 80 °C.

[0029] Preferably, the reaction time is 1-16 h.

[0030] Preferably, the reaction time is 2-14 h.

[0031] Preferably, the reaction time is 12 h.

[0032] Compared with the prior art, the method for preparing diphenyldiazeline or its derivatives by catalytic oxidation of aniline or its derivatives according to the present invention has the following advantages:

[0033] (1) The present invention uses depleted uranium waste as raw material to prepare catalyst, which effectively solves the problem of safe disposal and reuse of depleted uranium in my country’s nuclear energy utilization;

[0034] (2) The aniline or its derivatives used in this invention are common basic raw materials in industry, and are inexpensive and readily available.

[0035] (3) The present invention uses cheap and readily available tert-butyl hydrogen peroxide as an oxidant and the reaction temperature is moderate. Compared with the traditional method that uses peracetic acid, Pb(OAc)4, Hg(OAc)2, BaMnO4 and other oxidants, the cost of oxidants is greatly reduced and the problem of toxic emissions generated by the use of oxidants is solved.

[0036] (4) The method described in this invention can catalytically oxidize aniline or its derivatives to the corresponding diphenyldiazene or its derivatives, with good specificity and high yield of the target product.

[0037] The present invention will be further described in detail below with reference to specific embodiments. The scope of protection of the present invention is not limited thereto. Unless otherwise specified, all raw materials used in the following embodiments can be purchased commercially. Attached Figure Description

[0038] Figure 1 X-ray diffraction crystal structure diagram of the prepared catalyst UO4·2H2O;

[0039] Figure 2Transmission electron microscope image of the prepared catalyst UO4·2H2O;

[0040] Figure 3 Scanning electron microscope image of the prepared catalyst UO4·2H2O;

[0041] Figure 4 Nitrogen isothermal adsorption curve of the prepared UO4·2H2O catalyst;

[0042] Figure 5 Mass spectrum of diphenyldiazene, the product synthesized by the method described in Example 1;

[0043] Figure 6 Mass spectrum of diphenyldiazene, the product synthesized by the method described in Example 2;

[0044] Figure 7 Mass spectrum of diphenyldiazene, the product synthesized by the method described in Example 3;

[0045] Figure 8 Mass spectrum of diphenyldiazene, the product synthesized by the method described in Example 4;

[0046] Figure 9 Mass spectrum of diphenyldiazene, the product synthesized by the method described in Example 5;

[0047] Figure 10 Mass spectrum of diphenyldiazene, the product synthesized by the method described in Example 6;

[0048] Figure 11 Mass spectrum of 2,2'-dimethyl-diphenyldiazene synthesized by the method described in Example 7;

[0049] Figure 12 Mass spectrum of 3,3'-dimethyldiphenyldiazene synthesized by the method described in Example 7;

[0050] Figure 13 Mass spectrum of 4,4'-dimethyl-diphenyldiazene synthesized by the method described in Example 7;

[0051] Figure 14 Mass spectrum of 4,4'-dichloro-diphenyldiazene synthesized by the method described in Example 7;

[0052] Figure 15 Mass spectrum of the product 4,4'-dibromo-diphenyldiazene synthesized by the method described in Example 7;

[0053] Figure 16 Mass spectrum of 4,4'-dimethoxy-diphenyldiazene synthesized by the method described in Example 7; Detailed Implementation

[0054] The present invention will be further described in detail below with reference to specific embodiments. The scope of protection of the present invention is not limited thereto. Unless otherwise specified, all raw materials used in the following embodiments can be purchased commercially.

[0055] Example 1: Synthesis of diphenyldiazene using different reaction solvents

[0056] Note: In Table 1, serial number 2 represents an embodiment of the present invention, and serial numbers 1, 3-6 represent comparative examples.

[0057] 1. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.66 g formic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0058] 2. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0059] 3. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 2.7 g n-butyric acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0060] 4. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline, 3.66 g formic acid and acetic acid solvent (mass ratio 1:1). While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0061] 5. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline, 3.66 g formic acid and n-butyric acid solvent (mass ratio 1:1). While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0062] 6. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline, 3.15 g acetic acid, and n-butyric acid solvent (mass ratio 1:1). While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0063] The yields of diphenyldiazepines obtained by the preparation methods described in 1-6 above were calculated, and the results are shown in Table 1 below:

[0064] Table 1 lists Example 1 (serial number 2) and Comparative Examples (serial numbers 1, 3-6) for the preparation methods described above, along with the yields of the product diphenyldiazene.

[0065] Serial Number catalyst solvent reaction temperature TBHP reaction time Product yield 1 <![CDATA[UO4·2H2O]]> Formic acid 80 ℃ 0.685 mL 12 h 83% 2 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 12 h 92% 3 <![CDATA[UO4·2H2O]]> butyric acid 80 ℃ 0.685 mL 12 h 76% 4 <![CDATA[UO4·2H2O]]> Formic acid + Acetic acid 80 ℃ 0.685 mL 12 h 69% 5 <![CDATA[UO4·2H2O]]> Formic acid + butyric acid 80 ℃ 0.685 mL 12 h 62% 6 <![CDATA[UO4·2H2O]]> Acetic acid + n-butyric acid 80 ℃ 0.685 mL 12 h 68%

[0066] The mass spectrum of the product synthesized by the above reaction is shown below. Figure 5 As shown (the mass spectra of the main products of the above 6 reactions are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1 below. The above results indicate that aniline can be catalytically synthesized into diphenyldiazepine using an organic solvent (formic acid, acetic acid, n-butyric acid, or a combination thereof) as the reaction solvent, tert-butyl hydroperoxide as the oxidant, and UO4·2H2O as the catalyst; and the yield of diphenyldiazepine obtained can reach up to 92% when acetic acid is used as the reaction solvent.

[0067]

[0068] Example 2: Synthesis of diphenyldiazene with different amounts of reaction solvent

[0069] 1. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 1.05 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0070] 2. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 2.1 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0071] 3. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0072] 4. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 4.2 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0073] 5. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 5.25 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0074] 6. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 6.3 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0075] The yields of diphenyldiazepines obtained by the preparation methods described in 1-6 above were calculated, and the results are shown in Table 2 below:

[0076] Table 2. Process parameters and yield of diphenyldiazene as described in Example 2.

[0077] Serial Number catalyst Solvent volume reaction temperature TBHP reaction time Product yield 1 <![CDATA[UO4·2H2O]]> 1.05 g 80 ℃ 0.685 mL 12 h 74% 2 <![CDATA[UO4·2H2O]]> 2.1 g 80 ℃ 0.685 mL 12 h 93% 3 <![CDATA[UO4·2H2O]]> 3.15 g 80 ℃ 0.685 mL 12 h 96% 4 <![CDATA[UO4·2H2O]]> 4.2 g 80 ℃ 0.685 mL 12 h 92% 5 <![CDATA[UO4·2H2O]]> 5.25 g 80 ℃ 0.685 mL 12 h 72% 6 <![CDATA[UO4·2H2O]]> 6.3 g 80 ℃ 0.685 mL 12 h 68%

[0078] The mass spectrum of the main product obtained from the above reaction is shown below. Figure 6 As shown in the figure (the mass spectra of the main products of the above 6 reactions are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1 below. The above results show that acetic acid can be used as a reaction solvent (the mass ratio of acetic acid to aniline is 1-67:1), tert-butylhydrogen peroxide can be used as an oxidant, and UO4·2H2O can be used as a catalyst to catalyze the synthesis of diphenyldiazepine from aniline; at the same time, when the mass ratio of mesitylene to aniline is 21-45:1, the yield of diphenyldiazepine obtained by the reaction is above 90%.

[0079]

[0080] Example 3: Synthesis of diphenyldiazene at different reaction temperatures

[0081] 1. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 30 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0082] 2. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 40 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0083] 3. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 50 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0084] 4. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 60 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0085] 5. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 70 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0086] 6. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0087] 7. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 90 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0088] 8. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 100 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0089] 9. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 110 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazepine.

[0090] 10. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 120 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazepine.

[0091] The yields of diphenyldiazepines obtained by the preparation methods described in 1-10 above were calculated, and the results are shown in Table 3 below:

[0092] Table 3. Process parameters and yield of diphenyldiazene as described in Example 3.

[0093] Serial Number catalyst solvent reaction temperature TBHP reaction time Product yield 1 <![CDATA[UO4·2H2O]]> Acetic acid 30 ℃ 0.685 mL 12 h 62% 2 <![CDATA[UO4·2H2O]]> Acetic acid 40 ℃ 0.685 mL 12 h 74% 3 <![CDATA[UO4·2H2O]]> Acetic acid 50 ℃ 0.685 mL 12 h 82% 4 <![CDATA[UO4·2H2O]]> Acetic acid 60 ℃ 0.685 mL 12 h 86% 5 <![CDATA[UO4·2H2O]]> Acetic acid 70 ℃ 0.685 mL 12 h 91% 6 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 12 h 96% 7 <![CDATA[UO4·2H2O]]> Acetic acid 90 ℃ 0.685 mL 12 h 84% 8 <![CDATA[UO4·2H2O]]> Acetic acid 100 ℃ 0.685 mL 12 h 52% 9 <![CDATA[UO4·2H2O]]> Acetic acid 110 ℃ 0.685 mL 12 h 48% 10 <![CDATA[UO4·2H2O]]> Acetic acid 120 ℃ 0.685 mL 12 h 36%

[0094] The mass spectrum of the main product obtained from the above reaction is shown below. Figure 7 As shown in the figure (the mass spectra of the 10 main products are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1 below. The above results indicate that aniline can be catalytically synthesized into diphenyldiazepine using acetic acid as the reaction solvent, at a reaction temperature of 30-120 °C, with tert-butylhydrogen peroxide as the oxidant and UO4·2H2O as the catalyst; simultaneously, at a reaction temperature of 50-90 °C, the yield of diphenyldiazepine obtained is above 80%; and at a reaction temperature of 70-80 °C, the yield of diphenyldiazepine obtained is as high as 90% or more.

[0095]

[0096] Example 4: Synthesis of diphenyldiazene with different reaction times

[0097] 1. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 1 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0098] 2. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 2 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0099] 3. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 4 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0100] 4. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 6 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0101] 5. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 8 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0102] 6. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 10 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0103] 7. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0104] 8. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 14 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0105] 9. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 16 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0106] The yields of diphenyldiazepines obtained by the preparation methods described in 1-9 above were calculated, and the results are shown in Table 4 below:

[0107] Table 4. Process parameters and yield of diphenyldiazene as described in Example 4.

[0108] Serial Number catalyst solvent reaction temperature TBHP reaction time Product yield 1 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 1 h 32% 2 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 2 h 44% 3 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 4 h 56% 4 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 6 h 62% 5 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 8 h 73% 6 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 10 h 84% 7 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 12 h 92% 8 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 14 h 92% 9 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 16 h 92%

[0109] The mass spectrum of the main product obtained from the above reaction is shown below. Figure 8As shown in the figure (the mass spectra of the main products of the above 9 reactions are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1 below. The above results indicate that aniline can be catalytically synthesized into diphenyldiazepine using acetic acid as the reaction solvent, tert-butylhydrogen peroxide as the oxidant, and UO4·2H2O as the catalyst at a reaction time of 1-16 h; at a reaction time of 10-16 h, the yield of diphenyldiazepine obtained is above 80%; and at a reaction time of 12-16 h, the yield of diphenyldiazepine obtained is above 92%.

[0110]

[0111] Example 5: Synthesis of diphenyldiazene with different amounts of tert-butyl hydrogen peroxide added.

[0112] 1. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 1 mmol of tert-butyl hydrogen peroxide (i.e., 0.137 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0113] 2. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 2 mmol of tert-butyl hydrogen peroxide (i.e., 0.274 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0114] 3. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 3 mmol of tert-butyl hydrogen peroxide (i.e., 0.411 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0115] 4. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 4 mmol of tert-butyl hydrogen peroxide (i.e., 0.584 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0116] 5. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0117] 6. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 6 mmol of tert-butyl hydrogen peroxide (i.e., 0.822 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0118] 7. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 7 mmol of tert-butyl hydrogen peroxide (i.e., 0.959 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0119] 8. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 8 mmol of tert-butyl hydrogen peroxide (i.e., 1.096 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0120] 9. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 9 mmol of tert-butyl hydrogen peroxide (i.e., 1.233 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0121] 10. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 10.0 mmol of tert-butyl hydrogen peroxide (i.e., 1.370 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0122] The yields of diphenyldiazepines obtained by the preparation methods described in 1-10 above were calculated, and the results are shown in Table 5 below:

[0123] Table 5. Process parameters and yield of diphenyldiazene as described in Example 5.

[0124] Serial Number catalyst solvent reaction temperature TBHP reaction time Product yield 1 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.137 mL 12 h 54% 2 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.247mL 12 h 63% 3 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.411 mL 12 h 75% 4 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.548 mL 12 h 92% 5 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.685 mL 12 h 94% 6 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.822 mL 12 h 86% 7 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 0.959 mL 12 h 82% 8 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 1.096 mL 12 h 78% 9 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 1.233 mL 12 h 72% 10 <![CDATA[UO4·2H2O]]> Acetic acid 80 ℃ 1.370 mL 12 h 58%

[0125] The mass spectrum of the main product obtained from the above reaction is shown below. Figure 9 As shown in the figure (the mass spectra of the main products of the above 10 reactions are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1 below. The above results show that when the molar ratio of oxidant tert-butyl hydroperoxide to aniline is 1-14:1, acetic acid is used as the reaction solvent, and UO4·2H2O is used as the catalyst, aniline can be synthesized into diphenyldiazepine; at the same time, when the molar ratio of oxidant tert-butyl hydroperoxide to aniline is 1-6:1, the product yield is higher than 80%; and when the molar ratio of oxidant tert-butyl hydroperoxide to aniline is 6-7:1, the product yield is as high as 92% or more.

[0126]

[0127] Example 6 Synthesis of diphenyldiazene with different catalyst addition amounts

[0128] 1. Add 1.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0129] 2. Add 5.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0130] 3. Add 10.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0131] 4. Add 15.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0132] 5. Add 20.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0133] 6. Add 25 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0134] 7. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0135] 8. Add 35.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0136] 9. Add 40.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0137] 10. Add 45.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0138] 11. Add 50.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.093 g aniline and 3.15 g acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product diphenyldiazene.

[0139] The yields of diphenyldiazepines obtained by the preparation methods described in 1-11 above were calculated, and the results are shown in Table 6 below:

[0140] Table 6. Process parameters and yield of diphenyldiazene as described in Example 6

[0141] Serial Number catalyst solvent reaction temperature TBHP reaction time Product yield 1 1.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 12% 2 5.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 38% 3 10.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 47% 4 15.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 56% 5 20.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 75% 6 25.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 88% 7 30.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 96% 8 35.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 96% 9 40.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 92% 10 45.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 87% 11 50.0 mg Acetic acid 80 ℃ 0.685 mL 12 h 85%

[0142] The mass spectrum of the main product obtained from the above reaction is shown below. Figure 10 As shown (the mass spectra of the main products of the above 11 reactions are the same, so only one mass spectrum is provided), the structural formula of the product is shown in Formula 1 below. The above results indicate that, using acetic acid as the reaction solvent, tert-butyl hydroperoxide as the oxidant, and UO4·2H2O as the catalyst, when the ratio of catalyst to aniline or its derivative is 1-50 mg : 1 mol, aniline can be catalytically synthesized into diphenyldiazepine; and when the ratio of catalyst to aniline or its derivative is 25-50 mg : 1 mol, the yield of diphenyldiazepine obtained is higher than 80%; simultaneously, when the ratio of catalyst to aniline or its derivative is 30-40 mg : 1 mol, the yield of diphenyldiazepine obtained can reach over 92%.

[0143]

[0144] Example 7 Synthesis of diphenyldiazene derivatives using different aniline derivatives

[0145] 1. 30.0 mg of UO4·2H2O catalyst was added to a 25 mL reaction tube, followed by 0.107 g of o-methylaniline and 3.15 g of acetic acid. While stirring at 80 °C, 5 mmol of tert-butyl hydroperoxide (i.e., 0.685 mL of a 70% tert-butyl hydroperoxide aqueous solution) was added dropwise. The reaction was allowed to proceed for 12 h. The product was then obtained by filtration, distillation, and recrystallization to yield 2,2'-dimethyl-diphenyldiazene. The mass spectrum of the product is shown below. Figure 11 As shown, the structural formula is shown in Equation 2 below.

[0146]

[0147] 2. 30.0 mg of UO4·2H2O catalyst was added to a 25 mL reaction tube, followed by 0.107 g of m-methylaniline and 3.15 g of acetic acid. While stirring at 80 °C, 5 mmol of tert-butyl hydroperoxide (i.e., 0.685 mL of a 70% tert-butyl hydroperoxide aqueous solution) was added dropwise. The reaction was allowed to proceed for 12 h. The product was then obtained by filtration, distillation, and recrystallization to yield 3,3'-dimethyl-diphenyldiazene. The mass spectrum of the product is shown below. Figure 12 As shown, the structural formula is shown in Equation 3 below.

[0148]

[0149] 3. 30.0 mg of UO4·2H2O catalyst was added to a 25 mL reaction tube, followed by 0.107 g of p-methylaniline and 3.15 g of acetic acid. While stirring at 80 °C, 5 mmol of tert-butyl hydroperoxide (i.e., 0.685 mL of a 70% tert-butyl hydroperoxide aqueous solution) was added dropwise. The reaction was allowed to proceed for 12 h. The product was then obtained by filtration, distillation, and recrystallization to yield 4,4'-dimethyl-diphenyldiazene. The mass spectrum of the product is shown below. Figure 13 As shown, the structural formula is shown in Equation 4 below.

[0150]

[0151] 4. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.127 g of p-chloroaniline and 3.15 g of acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydroperoxide (i.e., 0.685 mL of 70% tert-butyl hydroperoxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product 4,4'-dichloro-diphenyldiazene. The mass spectrum of the product is shown below. Figure 14 As shown, the structural formula is shown in Equation 5 below.

[0152]

[0153] 5. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.172 g of p-bromoaniline and 3.15 g of acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydroperoxide (i.e., 0.685 mL of 70% tert-butyl hydroperoxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product 4,4'-dibromo-diphenyldiazene. The mass spectrum of the product is shown below. Figure 15 As shown, the structural formula is shown in Equation 6 below.

[0154]

[0155] 6. Add 30.0 mg of UO4·2H2O catalyst to a 25 mL reaction tube, then add 0.123 g of p-methoxyaniline and 3.15 g of acetic acid. While stirring at 80 °C, add 5 mmol of tert-butyl hydrogen peroxide (i.e., 0.685 mL of 70% tert-butyl hydrogen peroxide aqueous solution). React for 12 h, then filter, distill, and recrystallize to obtain the product 4,4'-dimethoxy-diphenyldiazene. The mass spectrum of the product is shown below. Figure 16 As shown, the structural formula is shown in Equation 7 below.

[0156]

[0157] The yields of the diphenyldiazene derivatives obtained by the preparation methods described in 1-6 above were calculated, and the results are shown in Table 7 below:

[0158] Table 7. Process parameters and product yield of the preparation method described in Example 7

[0159] Serial Number aniline substrate solvent reaction temperature TBHP reaction time Product yield 1 o-methylaniline Acetic acid 80 ℃ 0.685 mL 12 h 85% 2 m-methylaniline Acetic acid 80 ℃ 0.685 mL 12 h 83% 3 p-Toluidine Acetic acid 80 ℃ 0.685 mL 12 h 94% 4 p-Chloroaniline Acetic acid 80 ℃ 0.685 mL 12 h 97% 5 p-Bromoaniline Acetic acid 80 ℃ 0.685 mL 12 h 97% 6 p-Methoxyaniline Acetic acid 80 ℃ 0.685 mL 12 h 94%

[0160] The mass spectra of the main products in reactions 1-6 above are as follows: Figure 11-16 As shown above, the results indicate that using acetic acid as the reaction solvent, tert-butyl hydroperoxide as the oxidant, and UO4·2H2O as the catalyst, 2,2'-dimethyl-diphenyldiazene can be catalytically synthesized from o-methylaniline in a yield of 85%; 3,3'-dimethyl-diphenyldiazene from m-methylaniline in a yield of 83%; 4,4'-dimethyl-diphenyldiazene from p-methylaniline in a yield of 94%; 4,4'-dichloro-diphenyldiazene from p-chloroaniline in a yield of 97%; 4,4'-dibromo-diphenyldiazene from p-bromoaniline in a yield of 97%; and 4,4'-dimethoxy-diphenyldiazene from p-methoxyaniline in a yield of 94%. Therefore, the method of this invention can catalytically synthesize diphenyldiazene or its derivatives from aniline or its derivatives, and the yield of the target product is high.

[0161] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for synthesizing diphenyldiazene or its derivatives using a uranium-depleted catalyst UO4·2H2O, characterized in that: The catalyst is UO4·2H2O; the raw material for synthesizing diphenyldiazeline or its derivatives is aniline or its derivatives, the structural formula of which is shown in formula (Ⅰ) below, and the structural formula of the product is shown in formula (Ⅱ) below: R1-R5 are selected from any one of hydrogen, methyl, chlorine, bromine, and methoxy, respectively. The method uses acetic acid as the reaction solvent and tert-butyl hydroperoxide (TBHP) as the oxidant.

2. The method according to claim 1, characterized in that: The catalyst UO4·2H2O is prepared by using U3O8, which is produced by depleting UF6, as raw material. Concentrated acid is used as a solvent to completely dissolve U3O8. Deionized water is added to form a transparent uranyl salt solution. Then hydrogen peroxide is added, and after stirring, the solid product is separated by centrifugation, washed, dried and calcined to obtain the catalyst.

3. The method according to claim 1, characterized in that: The catalyst is used in a mass ratio of 1-50 mg to 1 mmol; the reaction solvent is used in a mass ratio of 1-67:1 to aniline or its derivative; the reaction temperature is 30-120 °C; and the reaction time is 1-16 h.

4. The method according to claim 3, characterized in that: The catalyst was used in a ratio of 30 mg to 1 mmol of aniline or its derivative; the reaction solvent was used in a mass ratio of 33:1 of aniline or its derivative; the reaction temperature was 80 °C; the reaction time was 12 h; and the product was obtained by filtration, distillation, and recrystallization to obtain diphenyldiazene or its derivative.

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