One-pot preparation method of diphenyl aniline

Abstract

The invention provides a one-pot preparation method of diphenyl aniline, which comprises the following steps: by taking 3, 5-dibromo nitrobenzene and phenylboronic acid as reaction raw materials, adding alkali and a solvent under the action of a catalyst and a ligand, carrying out cross-coupling reaction, then carrying out one-pot reaction with a reducing reagent, and filtering and recrystallizing to obtain 3, 5-diphenyl aniline. The one-pot method for preparing phenylaniline is provided for the first time, the reaction catalyst types are few, the catalysis dosage is low, and the yield is high. The method has the advantages of simple post-treatment of reaction steps, simplified reaction steps and treatment process, low cost and high product purity, and is suitable for amplified reaction and industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, relates to diphenylaniline, and specifically relates to a one-pot preparation method of diphenylaniline. Background Art

[0002] Perovskite cells (PSCs) are solar cells that use perovskite-type organic metal halide semiconductors as light-absorbing materials. They belong to the third generation of solar cells, also known as new concept solar cells. Perovskite was first discovered by German scientist Gustav Rose in 1839. In 2006, perovskite was first used in photovoltaic cells. In 2009, Japanese scientist Miyasaka took the lead in using perovskite materials in dye-sensitized solar cells as light-absorbing materials, achieving a photoelectric conversion efficiency of 3.8%. In October 2021, the single-junction perovskite cell of the Ulsan National Institute of Science and Technology in South Korea had a photoelectric conversion efficiency of 25.8%, and in August 2022, the photoelectric conversion efficiency of the Institute of Semiconductors of the Chinese Academy of Sciences was 25.6%. In October 2020, the photoelectric conversion efficiency of the all-perovskite tandem cell of the Renewable Energy Laboratory of the U.S. Department of Energy was 23.1%, and the photoelectric conversion efficiency of the research group of Tan Hairen at Nanjing University exceeded 28.0%. In December 2020, the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem cell of Oxford Photovoltaics in the UK reached 29.5%. In November 2021, the German Helmholtz Center further increased the photoelectric conversion efficiency to 29.8%. In July 2022, the Swiss Federal Institute of Technology in Lausanne broke through 31.3%. On November 3, 2023, according to the latest certification report of the National Renewable Energy Laboratory (NREL) of the United States, the efficiency of the crystalline silicon-perovskite tandem cell independently developed by the Chinese photovoltaic company Longi Green Energy Technology Co., Ltd. reached 33.9%, which is the highest record of crystalline silicon-perovskite tandem cell efficiency in the world.

[0003] In recent years, perovskite solar cells have developed rapidly, from the initial 3.8% photoelectric conversion efficiency (PCE) to 26.08%, but their high material prices and poor stability are still the main obstacles to commercial applications. Hole transport layer materials (HTMs), as an important component of PSCs, not only control the extraction and transmission of holes, but also protect perovskite from direct contact with the surrounding environment. Hole transport materials are an important class of organic optoelectronic functional materials. They can effectively improve the injection efficiency and transmission efficiency of holes in the device. They are the key factors affecting the efficiency of optoelectronic devices such as solar cells and OLED devices. Therefore, the research on hole transport materials has attracted much attention in recent years. Small molecule hole transport materials are widely used because of their simple preparation and high hole mobility. However, small molecule hole transport materials generally have poor solubility, low glass transition temperature, and poor film forming properties, which affect the efficiency of the device. Therefore, seeking new hole transport materials with excellent performance has always been a hot topic in this field.

[0004] Triphenylamine (TPA) compounds are centered on nitrogen atoms. The large steric hindrance and hyperconjugation effect make the nitrogen atom free radicals have high stability and strong modifiability. This unique free radical property makes triphenylamine compounds have high hole mobility and low ionization potential, so they are widely used in hole transport materials. In recent years, there have been frequent reports on TPA in the fields of electrochromism, display, solar cells, etc. at home and abroad. TPA accounts for a high proportion in hole transport materials due to its advantages such as high hole mobility and good stability. However, the synthesis of this type of material is relatively complex, and there are deficiencies such as limited sites in chemical modification, which makes it difficult to meet the current rapid development of optoelectronic materials, especially perovskite solar cells. Therefore, it is urgent to develop new high-transport hole materials with simple synthesis, flexible and changeable structural modification, and good material performance. Among them, 3,5-diphenylaniline (DPA) has a similar structure to TPA, many modifiable sites, and better material performance. At the same time, it can be used as a structural unit with other structural units to construct new high-efficiency hole transport materials. In recent years, it has been favored by a large number of scientific researchers. A search using the Reaxys database found that the number of patent applications based on this structural unit has increased in recent years, including South Korea (6), China (3), the United States (2) and Europe (1), mainly distributed in Asia, especially in Europe, the United States and China in 2023, which shows that the DPA structure is an advantageous new structure and material.

[0005] According to literature research, the main synthesis methods for DPA are:

[0006] First, palladium-catalyzed dibromoaniline:

[0007]

[0008] In 2019, the patent (KR102052070) applied by Samsung was mainly obtained by coupling iodobenzene and dibromoaniline with tetrakis(triphenylphosphine)palladium catalysis. The reaction involves multiple steps and the steps are relatively complicated. Sometimes the reaction conditions need to be strictly controlled and the raw material prices are relatively high.

[0009] Second, palladium-catalyzed dichloroaniline:

[0010]

[0011] According to published patents (KR2018 / 44695, KR102193837), the cross-coupling reaction of phenylboric acid and dichloroaniline catalyzed by tetrakis(triphenylphosphine)palladium is poor due to the low reaction activity of the chlorinated product and the high substrate content.

[0012] Third, direct amination method:

[0013]

[0014] This method uses diphenyl bromobenzene as a raw material and directly aminates it via palladium catalysis. The reaction conditions are harsh, the raw material price is high, and the yield is not ideal.

[0015] Fourth, palladium-catalyzed two-step method:

[0016]

[0017] This method utilizes dibromonitrobenzene and phenylboric acid to carry out a first step coupling reaction under tetrakis(triphenylphosphine)palladium conditions, and then utilizes nitro reduction to prepare the product. This method has a wide range of raw materials, but the catalyst dosage is high, the post-processing is relatively complicated, and multiple catalysts are involved.

[0018] In summary, there are many methods for synthesizing DPA. Considering the raw materials, cost, reaction efficiency and other aspects, the fourth method is more efficient, but it also involves the use of multiple catalysts and reaction solvents. Therefore, it is particularly necessary to synthesize DPA using a new method. Summary of the invention

[0019] In view of the shortcomings of the prior art, the object of the present invention is to provide a one-pot preparation method of diphenylaniline to solve the technical problem that the preparation method of diphenylaniline (DPA) in the prior art has too many reaction reagents (reaction catalyst and solvent).

[0020] Another object of the present invention is to provide a one-pot preparation method of diphenylaniline, which solves the technical problems of complicated reaction steps and post-treatment in the preparation method of diphenylaniline (DPA) in the prior art.

[0021] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0022] A one-pot preparation method of diphenylaniline, which takes 3,5-dibromonitrobenzene and phenylboric acid as reaction raw materials, adds a base and a solvent under the action of a catalyst and a ligand, and after a cross-coupling reaction, reacts with a reducing agent in a one-pot manner, and obtains 3,5-diphenylaniline after filtering and recrystallization.

[0023] The catalyst is 10wt.% palladium on carbon, Pd(OAc)2 (palladium acetate), Pd2(dba)3 (trisdibenzylideneacetone dipalladium), Pd(TFA)2 (palladium (II) trifluoroacetate) or Pd2(allyl)2Cl2 (allylpalladium (II) chloride dimer).

[0024] The ligand is PPh3 (triphenylphosphine), P(o-Tol)3 (tri(o-methylphenyl)phosphine) or PCy3 (tricyclohexylphosphine).

[0025] The reducing agent is 85wt.% of hydrazine hydrate or hydrogen.

[0026] The cross-coupling reaction has a reaction temperature of 100 to 130° C. and a reaction time of 18 to 24 hours.

[0027] The reaction temperature of the one-pot reaction is 60-80°C and the reaction time is 6-8h.

[0028] The molar ratio of the reaction raw materials, the catalyst and the ligand is 1:0.1:0.1.

[0029] The base is potassium carbonate, cesium carbonate or cesium fluoride.

[0030] The solvent is a mixed solvent of toluene / water, a mixed solvent of toluene / ethanol / water or a mixed solvent of ethanol / water.

[0031] Compared with the prior art, the present invention has the following technical effects:

[0032] (I) The method of the present invention is the first to propose a one-pot method for preparing phenylaniline, with a small number of reaction catalysts, a low catalytic dosage and a high yield.

[0033] (II) The method of the present invention has simple post-processing of the reaction steps, simplifies the reaction steps and the processing process, has low cost, and has high product purity, and is suitable for scaled-up reactions and industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the H NMR spectrum of diphenylaniline.

[0035] Figure 2 This is the NMR carbon spectrum of diphenylaniline.

[0036] Figure 3 This is the infrared spectrum of diphenylaniline.

[0037] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0038] It should be noted that, unless otherwise specified, all raw materials in the present invention are raw materials known in the art.

[0039] The present invention provides a one-pot preparation method of diphenylaniline (i.e. 3,5-diphenylaniline), and the reaction equation of the method is:

[0040]

[0041] The diphenylaniline prepared by the invention is applied to the fields of perovskite cells and organic light emitting diodes (OLEDs).

[0042] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0043] Embodiment 1:

[0044] The present embodiment provides a one-pot preparation method of diphenylaniline, which is carried out according to the following steps: under nitrogen protection, add 0.5mmol of 3,5-dibromonitrobenzene, 1.1mmol of phenylboric acid, 0.16mmol of 10wt.% palladium carbon catalyst, 0.16mmol of PPh3, 1.5mmol of potassium carbonate, and evacuate and fill with nitrogen three times. Use a syringe to add 10mL toluene / water (v / v=5 / 1), heat the oil bath to 100°C, and react for 18h. Cool the room temperature, TLC (thin layer chromatography) monitors the reaction completely, then add 3mL of ethanol, warm to 80°C, slowly drip 1.5mmol of 85wt.% hydrazine hydrate, drip and finish, reflux reaction for 3 hours. Cool, filter with suction, and the filtrate is spin-dried to obtain a light yellow solid by recrystallization, with a yield of 78%.

[0045] The nuclear magnetic hydrogen spectrum of the light yellow solid obtained in this example is as follows Figure 1 As shown, the NMR carbon spectrum is as follows Figure 2 As shown, the infrared spectrum of the light yellow solid obtained in this embodiment is as shown Figure 3 As shown, from Figures 1 to 3 It can be seen from the characterization that the light yellow solid obtained in this example is the target product diphenylaniline.

[0046] Embodiment 2:

[0047] The present embodiment provides a one-pot preparation method of diphenylaniline, which is carried out according to the following steps: under nitrogen protection, add 0.5mmol of 3,5-dibromonitrobenzene, 1.1mmol of phenylboric acid, 0.16mmol of 10wt.% palladium carbon catalyst, 0.16mmol of PPh3, 1.5mmol of potassium carbonate, and evacuate and fill with nitrogen three times. Use a syringe to add 10mL toluene / water (v / v=5 / 1), heat the oil bath to 100°C, and react for 18h. Cool the room temperature, monitor the reaction completely by TLC, then add 3mL of ethanol, warm to 80°C, and pass hydrogen reflux reaction for 6 hours. Cool, filter, and the filtrate is spin-dried and recrystallized to obtain a light yellow solid with a yield of 74%.

[0048] The nuclear magnetic hydrogen spectrum of the light yellow solid obtained in this example is Figure 1 Basically the same, the NMR carbon spectrum is Figure 2 Basically the same, infrared spectrum and Figure 3The results are basically the same, indicating that the light yellow solid obtained in this example is the target product diphenylaniline.

[0049] Embodiment 3:

[0050] The present embodiment provides a one-pot preparation method of diphenylaniline, which is carried out according to the following steps: under nitrogen protection, add 0.5 mmol 3,5-dibromonitrobenzene, 1.1 mmol phenylboric acid, 0.16 mmol Pd (OAc) 2, 0.16 mmol P (o-Tol) 3, 1.5 mmol cesium carbonate, and evacuate and fill with nitrogen three times. Use a syringe to add 10 mL toluene / ethanol / water (v / v = 5 / 1 / 1), heat the oil bath to 100 ° C, and react for 18 hours. Cool the room temperature, TLC monitors the reaction completely, then add 3 mL ethanol, warm to 80 ° C, slowly drip 1.5 mmol 85wt.% hydrazine hydrate, drip and finish, reflux reaction for 3 hours. Cool, filter with suction, and the filtrate is spin-dried to obtain a light yellow solid by recrystallization, with a yield of 70%.

[0051] The nuclear magnetic hydrogen spectrum of the light yellow solid obtained in this example is Figure 1 Basically the same, the NMR carbon spectrum is Figure 2 Basically the same, infrared spectrum and Figure 3 The results are basically the same, indicating that the light yellow solid obtained in this example is the target product diphenylaniline.

Claims

1. A one-pot preparation method of diphenylaniline, characterized in that, The method uses 3,5-dibromonitrobenzene and phenylboric acid as reaction raw materials, adds a base and a solvent under the action of a catalyst and a ligand, and after a cross-coupling reaction, reacts with a reducing agent in a one-pot method, and obtains 3,5-diphenylaniline after filtration and recrystallization.

2. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that The catalyst is 10wt.% palladium carbon, Pd(OAc)2, Pd2(dba)3, Pd(TFA)2 or Pd2(allyl)2Cl2.

3. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that, The ligand is PPh3, P(o-Tol)3 or PCy3.

4. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that: The reducing agent is 85wt.% of hydrazine hydrate or hydrogen.

5. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that, The cross-coupling reaction has a reaction temperature of 100 to 130° C. and a reaction time of 18 to 24 hours.

6. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that: The reaction temperature of the one-pot reaction is 60-80°C and the reaction time is 6-8h.

7. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that: The molar ratio of the reaction raw materials, the catalyst and the ligand is 1:0.1:0.

1.

8. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that: The base is potassium carbonate, cesium carbonate or cesium fluoride.

9. The one-pot preparation method of diphenylaniline as claimed in claim 1, characterized in that: The solvent is a mixed solvent of toluene / water, a mixed solvent of toluene / ethanol / water or a mixed solvent of ethanol / water.

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