Preparation method of 4 '-chloro-2-aminobiphenyl
By using sulfur trioxide-pyridine complex and titanium dioxide nanotube photocatalysts instead of traditional methods, combined with microwave-assisted hydrolysis, the high cost and pollution problems in the preparation of 4'-chloro-2-aminobiphenyl were solved, and an efficient and environmentally friendly production process was achieved.
Patent Information
- Application Number
- CN202510833401.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-20
- Publication Date
- 2025-10-14
AI Technical Summary
Existing 4'-chloro-2-aminobiphenyl preparation technologies have problems such as high cost, severe pollution, many by-products, and low yield. In particular, traditional methods use expensive catalysts and hazardous chemicals, resulting in high production costs and difficulty in control.
Sulfur trioxide-pyridine complex is used to replace highly corrosive chlorosulfonic acid, combined with titanium dioxide nanotube photocatalyst and bio-based cysteine, and microwave-assisted hydrolysis is used to optimize reaction conditions to reduce waste gas emissions and energy consumption and improve reaction efficiency.
The green and environmentally friendly synthesis of 4'-chloro-2-aminobiphenyl is achieved, production costs are reduced, product yield and purity are improved, and by-product generation is reduced.
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Figure CN120774797A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of organic synthesis, and particularly relates to a preparation method of 4'-chloro-2-amino biphenyl. BACKGROUND
[0002] In the technical field of pesticides, organic synthesis intermediates are crucial for the research and production of pesticides. As a key organic synthesis intermediate, 4'-chloro-2-amino biphenyl plays an important role in the field of pesticides, especially in the preparation of the fungicide boscalid. Boscalid belongs to the class of succinate dehydrogenase inhibitors in the mitochondrial respiratory chain, and has excellent control effect on various diseases such as powdery mildew and gray mold, and has no cross resistance with other fungicides, so it is widely used in the market. This makes the synthesis and preparation technology of 4'-chloro-2-amino biphenyl attract much attention, and the development of the preparation technology directly affects the research and production process of related products in the pesticide industry.
[0003] In order to prepare 4'-chloro-2-amino biphenyl, there are various conventional means in the industry. A common method is to use palladium to catalyze the reaction of o-nitrochlorobenzene (or o-nitrobenzyl bromide) and p-chlorobenzene boronic acid to obtain 4'-chloro-2-nitro biphenyl, and then use Pd / C for reduction. In addition, there are methods for synthesizing 4'-chloro-2-amino biphenyl using 9-fluorenone as a raw material through a series of processes such as ring opening, chlorination, and Hofmann degradation, and different process routes exist in these methods. These methods can achieve the preparation of 4'-chloro-2-amino biphenyl to some extent, and provide a way for related research and production.
[0004] However, these conventional means in the prior art have obvious defects. The commonly used palladium catalysis and Pd / C reduction method uses expensive p-chlorobenzene boronic acid, palladium catalyst and Pd / C, which increases the production cost. The synthesis method using 9-fluorenone as a raw material also has many problems. Some use the dangerous chemical antimony trichloride as a catalyst in the chlorination stage, which leads to an increase in side reactions, difficulty in product purification, and low yield. Some use the toxic and dangerous chemical chlorine as a chlorinating agent, and chlorination under heating conditions, which easily produces chlorinated isomers and polychlorinated products, making separation and purification very difficult, and the actual yield is not ideal. At the same time, with the continuous expansion of the application of 9-fluorenone in medicine, dyes, electronic materials and other fields, the supply of its raw material becomes tight, and the price rises sharply, making it no longer cost-effective to synthesize 4'-chloro-2-amino biphenyl using 9-fluorenone as a raw material. Therefore, it is necessary to provide a preparation method of 4'-chloro-2-amino biphenyl, which can improve the environmental friendliness and economy of the process while ensuring the yield and purity of the product. SUMMARY
[0005] In order to improve the environmental friendliness and economy of the preparation method of 4'-chloro-2-amino biphenyl, the present application provides a preparation method of 4'-chloro-2-amino biphenyl.
[0006] The application provides a preparation method of 4'-chloro-2-amino biphenyl. A preparation method of 4'-chloro-2-amino biphenyl comprises the following steps: S1, p-dichlorobenzene is added to a solvent, and sulfur trioxide-pyridine compound is added under stirring; after the addition is completed, heating and stirring reaction is carried out, then cooling is performed, thionyl chloride is added, heating and stirring reflux reaction is carried out, then cooling and quenching reaction are performed, and after extraction, washing, drying and concentration, 2,5-dichlorobenzene sulfonyl chloride is obtained; S2, 2,5-dichlorobenzene sulfonyl chloride is dissolved in a solvent, and aniline hydrochloride and sodium bicarbonate solution are added under stirring; after the addition is completed, heating and stirring reaction is carried out, then quenching reaction is performed after reaction, and after extraction, washing, drying and concentration, 2,5-dichloro-N-phenyl benzene sulfonamide is obtained; S3, 2,5-dichloro-N-phenyl benzene sulfonamide, cysteine and titanium dioxide nanotube are mixed, and a solvent is added; under a protective atmosphere, photocatalysis is started, heating and stirring reaction is carried out, then cooling is performed after reaction is completed, hydrogen peroxide solution is added for stirring reaction in the dark, quenching reaction is performed, and after extraction, washing, drying and concentration, 2-chloro-6H-dibenzothiazine dioxide is obtained; S4, 2-chloro-6H-dibenzothiazine dioxide, zinc powder and glacial acetic acid are mixed, heating and stirring reaction is carried out in the dark, then cooling, filtering and reduced pressure concentration are performed to obtain an intermediate; the intermediate and p-toluenesulfonic acid are mixed, a solvent is added, microwave-assisted hydrolysis is carried out, then cooling is performed after reaction, the pH is adjusted to be alkaline, and after extraction, washing, drying, concentration and recrystallization, 4'-chloro-2-amino biphenyl is obtained.
[0007] Sulfur trioxide-pyridine compound is used to replace strongly corrosive chlorosulfonic acid to reduce hydrogen chloride waste gas emission from the source; titanium dioxide nanotube organic photocatalyst is used to drive intramolecular Smiles rearrangement at near room temperature, biological cysteine is used to replace inorganic sulfur source, sulfur-containing waste gas emission is completely eliminated, reaction efficiency is improved, and energy consumption is reduced; combined with microwave precise energy transmission to accelerate rearrangement reaction, the traditional hydrolysis process of several hours is shortened to minutes, high-temperature solvent decomposition of carcinogenic byproducts is avoided, reaction efficiency is improved, and byproduct generation is reduced; the above process is reconstructed through molecular activation path to realize catalyst recycling and solvent biodegradation closed loop, the problems of high toxicity, high energy consumption and high pollution in the traditional process are solved, the comprehensive production cost is reduced, and a green, environmentally friendly and high yield and purity industrialized scheme for synthesis of biphenylamine compounds is provided.
[0008] Preferably, in the step S1, the temperature is controlled to be below 10℃ when the sulfur trioxide-pyridine compound is added, and after the addition is completed, the temperature is increased to 40-45℃, and the reaction is stirred at a speed of 300-400 rpm for 2-3 h.
[0009] The above process uses low-temperature feeding to inhibit the local aggregation of sulfur trioxide to initiate polysulfonation side reactions, and then uses moderate-speed stirring to achieve directional monosulfonation of aromatic rings and reduce the generation of disulfonic acid isomers; the steric hindrance effect of pyridine complex is used to cooperate with mild reaction conditions to improve the selectivity and purity of sulfuryl chloride, while avoiding the use of corrosive fuming sulfuric acid and complex temperature control devices, reducing production costs, and providing high-purity raw materials for subsequent steps.
[0010] Preferably, after adding thionyl chloride in step S1, stirring at a speed of 300-400 rpm at 35-45°C for 1.5-2h.
[0011] The above process can precisely control the energy barrier of the chlorination reaction, and uses a mild temperature range in step S1 to achieve efficient conversion of sulfonic acid to sulfuryl chloride, while using uniform stirring to inhibit molecular degradation caused by local excess of thionyl chloride; this method combines the proton capture ability of pyridine complex and the self-balancing characteristics of the reflux system to block the side reactions of sulfuryl chloride thermal decomposition, while avoiding the use of highly toxic phosphorus pentachloride or high-energy vacuum operation, improving the stability of the product, reducing the corrosion risk, and providing high-activity raw materials for subsequent coupling reactions.
[0012] Preferably, the solvent in step S2 includes methyltetrahydrofuran and water.
[0013] The use of methyltetrahydrofuran and water as a complex solvent synchronously optimizes the solubility of sulfuryl chloride and the dispersibility of aniline salt by using its controllable lipophilic-hydrophilic balance characteristics. Compared to the traditional single organic solvent system, this design accelerates the nucleophilic substitution process through the microphase interface catalytic effect, blocks the disulfurylation side reaction, and solves the environmental accumulation risk of halogenated solvents and the explosion hazard of tetrahydrofuran peroxide by virtue of the bio-based source and full biodegradability of methyltetrahydrofuran, achieving a synergistic improvement in reaction efficiency and green safety.
[0014] Preferably, in step S2, the temperature is controlled below 5°C when adding aniline hydrochloride and sodium bicarbonate solution, and after completion of the addition, the temperature is raised to 20-30°C and stirred at a speed of 250-300 rpm for 4-5h.
[0015] The above process uses near-ice-point temperature to inhibit the hydrolysis of sulfuryl chloride and the free radicalization of aniline to initiate bimolecular side reactions, and then uses a mild warming environment combined with stirring to improve the selectivity of sulfonamide bonds; compared to the molecular degradation caused by high temperature or strong base conditions in traditional processes, this method uses the micro-buffering effect of sodium bicarbonate to release carbon dioxide to cooperate with controllable mass transfer processes, blocks the generation of sulfonic acid ester impurities, avoids the high toxicity of pyridine catalysts and the complex need for post-processing, improves the atom economy and operational safety.
[0016] Preferably, the molar ratio of 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube and hydrogen peroxide in step S3 is 1:1.2:(0.006-0.01):2.
[0017] The reaction according to the above molar ratio can effectively improve the reaction efficiency, and improve the yield and purity of the product.
[0018] Preferably, the photocatalytic condition in step S3 is a wavelength of 360-370 nm, a light intensity of 85-95 mW / cm 2 .
[0019] The specific wavelength range matches the maximum absorption band of the photocatalyst, ensuring that the photocatalyst is efficiently excited to the excited state, thereby optimizing the single electron transfer process and promoting the stable generation of sulfonyl radicals. At the same time, the moderate light intensity control not only ensures the sustained concentration of the excited state photocatalyst and maintains the efficient progress of the radical chain reaction, but also avoids the side reactions caused by excessive light intensity, thereby coordinating the rates of radical addition, cyclization and migration steps in the rearrangement reaction at the molecular level, improving the selectivity and conversion efficiency of Smiles rearrangement, and ensuring high yield and purity of the product.
[0020] Preferably, the photocatalytic reaction condition in step S3 is stirring at a speed of 400-500 rpm for 6.5-7.5 h at 45-55°C; the addition temperature of the hydrogen peroxide solution is 25-35°C, the addition time is 30-40 min, and the stirring speed is 200-300 rpm in the dark for 1.5-2.5 h.
[0021] The photocatalytic reaction under moderate temperature conditions not only accelerates the migration rate of photo-generated carriers, promotes the initiation and transmission of radical chain reaction, but also avoids catalyst deactivation or excessive hydrogenation side reactions caused by high temperature. Simultaneous intensive stirring significantly improves the mass transfer efficiency of gas-liquid-solid multiphase system, and inhibits the non-selective radical coupling caused by local high concentration. The low temperature and light-protected addition of hydrogen peroxide reduces the risk of thermal decomposition or photolysis, and the light-protected environment blocks the homolysis side reaction of hydrogen peroxide under ultraviolet light. Low temperature combined with gradient control of the addition rate effectively disperses the heat effect, preventing local temperature rise from causing rapid decomposition of hydrogen peroxide and uncontrollable release of active oxygen species. This temperature-stirring-feeding condition system design coordinates the balance between radical cyclization and redox steps in photocatalytic Smiles rearrangement at the molecular scale, improving the conversion efficiency and selectivity of the sulfilimine intermediate to the target product.
[0022] Preferably, the solvent of step S4 includes triethylene glycol dimethyl ether.
[0023] The high boiling point and strong polarity of triethylene glycol dimethyl ether provide a stable solvent environment for the high-temperature cracking step, ensuring that the sulfilactam intermediate remains uniformly dissolved during the cracking desulfonylation process, avoiding carbonization or excessive dehalogenation side reactions caused by local overheating; the strong coordination ability of multiple ether oxygen atoms in its molecule can selectively stabilize the active cationic intermediate generated during the reaction, inhibiting the formation of molecular rearrangement or polymerization byproducts, while reducing the transition state energy barrier to promote efficient C-S bond cleavage; the excellent chemical inertness of triethylene glycol dimethyl ether ensures that it does not decompose or undergo ring-opening side reactions in the cracking system, while its high miscibility with water greatly simplifies the phase separation step in the post-processing, achieving efficient product release and solvent recovery.
[0024] Preferably, the microwave-assisted hydrolysis conditions in step S4 are 145-155°C for 8-12 min, heating to 165-175°C for 16-20 min, and microwave power of 250-350 W.
[0025] Microwave energy drives the reaction system to achieve rapid and uniform dielectric heating at the molecular scale through molecular polarization and ionic conduction effects, avoiding temperature hysteresis and local overheating caused by traditional heat conduction; the staged gradient heating design precisely matches the kinetic requirements of sulfilactam C-S bond cleavage and desulfonylation, with the initial mild temperature preferentially activating acid-sensitive groups and inhibiting carbocation rearrangement side reactions, and the subsequent increased temperature providing sufficient activation energy to completely break the C-S bond, while precise control of microwave power maintains the dynamic balance of the reaction energy barrier, accelerating the intramolecular nucleophilic substitution process while avoiding excessive thermal cracking-induced dechlorination or cyclization impurities; this microwave-specific heating mechanism also significantly enhances proton transfer and solvation effects in concentrated acid media, promoting the stable conversion of hydrolysis intermediates; through the synergy of energy transfer and reaction kinetics, the product purity of 4'-chloro-2-aminobiphenyl is improved while ensuring efficient removal of the sulfonyl group, and the economic efficiency of the process is improved.
[0026] In summary, the present application includes at least one of the following beneficial technical effects: 1.Using sulfur trioxide-pyridine complex to replace strongly corrosive chlorosulfonic acid to reduce hydrogen chloride waste gas emission from the source; using titanium dioxide nanotube organic photocatalyst to drive intramolecular Smiles rearrangement at near room temperature, replacing inorganic sulfur source with biobased cysteine, completely eliminating sulfur-containing waste gas emission, improving reaction efficiency, and reducing energy consumption; combining microwave precise energy transmission to accelerate rearrangement reaction, shortening the traditional hydrolysis process of several hours to minutes, avoiding high-temperature solvent decomposition of carcinogenic byproducts, improving reaction efficiency, and reducing byproduct formation; the above process restructures the molecular activation path, realizes catalyst recycling and solvent biodegradation closed loop, solves the problems of high toxicity, high energy consumption, and high pollution in traditional process, reduces the comprehensive production cost, and provides a green, environmentally friendly, and high-yield, high-purity industrialization scheme for the synthesis of biphenylamine compounds.
[0027] 2.Using methyltetrahydrofuran and water as a compound solvent, using its controllable lipophilic-hydrophilic balance characteristics to simultaneously optimize the solubility of sulfonyl chloride and the dispersity of aniline salt, compared with the traditional single organic solvent system, this design accelerates the nucleophilic substitution process through the microphase interface catalysis effect, blocks the double sulfonylation side reaction, solves the environmental accumulation risk of halogenated solvents and the explosion hazard of tetrahydrofuran peroxide by virtue of the biobased source and full biodegradability of methyltetrahydrofuran, and realizes the synergistic improvement of reaction efficiency and green safety.
[0028] 3.The high boiling point and strong polarity characteristics of triethylene glycol dimethyl ether provide a stable solvent environment for the high-temperature cracking step, ensuring that the sulfilimine intermediate maintains a uniform dissolution state during the cracking desulfonylation process, avoiding carbonization or excessive halogen removal side reactions caused by local overheating; the strong coordination ability of multiple ether oxygen atoms in its molecule can selectively stabilize the active cation intermediate generated during the reaction, inhibit the formation of molecular rearrangement or polymerization byproducts, and at the same time promote the efficient breaking of the C-S bond by reducing the energy barrier of the transition state; the excellent chemical inertness of triethylene glycol dimethyl ether ensures that it does not decompose or ring-opening side reactions in the cracking system, and its high miscibility with water greatly simplifies the phase separation step in the post-processing, realizing the synergistic release of the product and the recovery of the solvent. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 The reaction structure in Example 1 of the present application is as follows. DETAILED DESCRIPTION
[0030] The present application discloses a preparation method of 4'-chloro-2-amino biphenyl, and the raw materials used in the present application can be obtained through commercially available materials except for special instructions. The present application is further described in detail in combination with the following examples: Raw material description: p-dichlorobenzene (CAS No.: 106-46-7), sulfur trioxide-pyridine complex (CAS No.: 26412-87-3), chlorosulfoxide (CAS No.: 7719-09-7), methyltetrahydrofuran (CAS No.: 96-47-9), aniline hydrochloride (CAS No.: 142-04-1), cysteine (CAS No.: 52-90-4), titanium dioxide nanotube (CAS No.: 1317-80-2), with the product code 100304, purchased from Jiangsu Xianfeng Nanometer Material Science and Technology Co., Ltd., p-toluenesulfonic acid (CAS No.: 104-15-4), triethylene glycol dimethyl ether (CAS No.: 112-49-2), 1,4-dioxane (CAS No.: 123-91-1).
[0031] Example 1 S1, p-dichlorobenzene was added to the solvent (dichloromethane, 10 mL / g of p-dichlorobenzene), and sulfur trioxide-pyridine complex was added under the condition of stirring at a speed of 350 rpm, and the addition was completed within 2 h, the temperature was controlled below 10 ℃, after the addition was completed, the temperature was increased to 40 ℃, and the reaction was stirred at a speed of 300 rpm for 3 h, then cooled to 0 ℃, and chlorosulfoxide was added, the addition was completed within 1 h, the molar ratio of p-dichlorobenzene, sulfur trioxide-pyridine complex and chlorosulfoxide was 1:1.05:1.8, the reaction was refluxed at 35 ℃ and stirred at a speed of 300 rpm for 2 h, then cooled to below 5 ℃, and the reaction was quenched using a mixture of ice ethanol and ice water with a volume ratio of 3:1, extracted with dichloromethane, washed successively with saturated sodium bicarbonate, 5% citric acid aqueous solution and saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain 2,5-dichlorobenzenesulfonyl chloride; S2, 2,5-dichlorobenzenesulfonyl chloride was dissolved in the solvent (methyltetrahydrofuran and water with a volume ratio of 3:1, 15 mL / g of 2,5-dichlorobenzenesulfonyl chloride), and aniline hydrochloride and 10% sodium bicarbonate aqueous solution were added in 3 batches under the condition of stirring at a speed of 300 rpm, the molar ratio of 2,5-dichlorobenzenesulfonyl chloride, aniline hydrochloride and sodium bicarbonate was 1:1.1:1.5, the temperature was controlled below 5 ℃ during the addition, after the addition was completed, the temperature was increased to 20 ℃, and the reaction was stirred at a speed of 250 rpm for 5 h, then the reaction liquid was poured into ice water to quench the reaction, extracted with ethyl acetate, washed successively with saturated sodium bicarbonate aqueous solution and saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain 2,5-dichloro-N-phenylbenzenesulfonamide; S3, 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube and hydrogen peroxide were mixed in a molar ratio of 1:1.2:0.006:2. 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine and titanium dioxide nanotube were mixed, solvent (water and ethanol in a mass ratio of 4:1, 12 mL / g of 2,5-dichloro-N-phenylbenzenesulfonamide) was added, titanium dioxide nanotube was pre-dispersed by ultrasonic, three vacuum-nitrogen cycles were performed, under the protection of nitrogen atmosphere, photocatalysis was started, photocatalytic wavelength was 360-370 nm, light intensity was 85 mW / cm 2 The reaction was stirred at 45°C at a speed of 400 rpm for 7.5 h, after the reaction was completed, it was cooled to 25°C, 30% hydrogen peroxide aqueous solution (pre-cooled to 5°C) was added, the addition time was 40 min, it was stirred in the dark at a speed of 200 rpm for 2.5 h, 10% sodium thiosulfate aqueous solution and ice water in a volume ratio of 1:1 were used to quench the reaction, ethyl acetate was used for extraction, it was washed with saturated sodium bicarbonate aqueous solution, 5% sodium thiosulfate aqueous solution (pH 8.5), 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine in sequence, it was dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain 2-chloro-6H-dibenzothiazine dioxide; S4, 2-chloro-6H-dibenzothiazine dioxide, zinc powder and p-toluenesulfonic acid were mixed in a molar ratio of 1:5:3, and the amount of glacial acetic acid was 8 mL / g of 2-chloro-6H-dibenzothiazine dioxide. 2-chloro-6H-dibenzothiazine dioxide, zinc powder and glacial acetic acid were mixed and stirred at a speed of 400 rpm, and then heated to 80°C and reacted in the dark for 1 h. After cooling to 25°C, it was filtered and concentrated under reduced pressure to obtain an intermediate. The intermediate and p-toluenesulfonic acid were mixed, a solvent (triglyme, 5 mL / g of the intermediate) was added, and microwave-assisted hydrolysis was performed at 145°C for 12 min and at 165°C for 20 min, with a microwave power of 350 W. After the reaction, it was cooled to below 40°C, poured into ice water, the pH was adjusted to 9 using 20% sodium hydroxide aqueous solution, extracted with ethyl acetate, washed with saturated sodium bicarbonate aqueous solution, 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine in sequence, dried with anhydrous sodium sulfate, concentrated under reduced pressure, recrystallized from a mixture of n-heptane and ethyl acetate in a volume ratio of 5:1, and decolorized with activated carbon to obtain 4'-chloro-2-aminobiphenyl.
[0032] Example 2 S1, p-dichlorobenzene was added to the solvent (dichloromethane, 10 mL / g of p-dichlorobenzene), and sulfur trioxide-pyridine complex was added under stirring at a speed of 350 rpm, and the addition was completed within 2 h, and the temperature was controlled below 10°C, and after the addition was completed, the temperature was raised to 45°C, and the reaction was stirred at a speed of 400 rpm for 2 h, and after cooling to 0°C, thionyl chloride was added, and the addition was completed within 1 h, and the molar ratio of p-dichlorobenzene, sulfur trioxide-pyridine complex and thionyl chloride was 1:1.05:1.8, and the reaction was refluxed at 45°C under stirring at a speed of 400 rpm for 1.5 h, and after cooling to below 5°C, the reaction was quenched using a mixture of ice ethanol and ice water in a volume ratio of 3:1, and dichloromethane was used for extraction, and saturated sodium bicarbonate, 5% citric acid aqueous solution and saturated brine were used for washing in sequence, and anhydrous magnesium sulfate was used for drying, and after concentration under reduced pressure, 2,5-dichlorobenzenesulfonyl chloride was obtained; S2, 2,5-dichlorobenzenesulfonyl chloride was dissolved in the solvent (methyltetrahydrofuran and water in a volume ratio of 3:1, 15 mL / g of 2,5-dichlorobenzenesulfonyl chloride), and aniline hydrochloride and 10% sodium bicarbonate aqueous solution were added in 3 batches under stirring at a speed of 300 rpm, and the molar ratio of 2,5-dichlorobenzenesulfonyl chloride, aniline hydrochloride and sodium bicarbonate was 1:1.1:1.5, and the temperature was controlled below 5°C during the addition, and after the addition was completed, the temperature was raised to 30°C, and the reaction was stirred at a speed of 300 rpm for 4 h, and after the reaction, the reaction solution was poured into ice water to quench the reaction, and ethyl acetate was used for extraction, and saturated sodium bicarbonate aqueous solution and saturated brine were used for washing in sequence, and anhydrous magnesium sulfate was used for drying, and after concentration under reduced pressure, 2,5-dichloro-N-phenylbenzenesulfonamide was obtained; S3, the molar ratio of 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube and hydrogen peroxide was 1:1.2:0.01:2. 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine and titanium dioxide nanotube were mixed, and the solvent (water and ethanol in a mass ratio of 4:1, 12 mL / g of 2,5-dichloro-N-phenylbenzenesulfonamide) was added, and the titanium dioxide nanotube was pre-dispersed by ultrasonic, and three vacuum-nitrogen cycles were performed, and under the protection of nitrogen atmosphere, photocatalysis was started, the photocatalysis wavelength was 360-370 nm, and the light intensity was 95 mW / cm 2 , and the reaction was stirred at a speed of 500 rpm for 6.5 h at 55°C, and after the reaction was completed, the temperature was cooled to 35°C, and 30% hydrogen peroxide aqueous solution (pre-cooled to 5°C) was added, and the addition time was 30 min, and the reaction was stirred at a speed of 300 rpm for 1.5 h in the dark, and 10% sodium thiosulfate aqueous solution and ice water in a volume ratio of 1:1 were used to quench the reaction, and ethyl acetate was used for extraction, and saturated sodium bicarbonate aqueous solution, 5% sodium thiosulfate aqueous solution (pH 8.5), 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine were used for washing in sequence, and anhydrous magnesium sulfate was used for drying, and after concentration under reduced pressure, 2-chloro-6H-dibenzothiazine dioxide was obtained; S4, the molar ratio of 2-chloro-6H-dibenzothiazine dioxide, zinc powder and p-toluenesulfonic acid is 1:5:3, the amount of glacial acetic acid is 8 mL / g of 2-chloro-6H-dibenzothiazine dioxide. 2-chloro-6H-dibenzothiazine dioxide, zinc powder and glacial acetic acid are mixed, stirred at a speed of 400 rpm, warmed to 80°C and reacted for 1 h in the dark, then cooled to 25°C, filtered, concentrated under reduced pressure to obtain an intermediate; the intermediate and p-toluenesulfonic acid are mixed, a solvent (triglycol dimethyl ether, 5 mL / g of the intermediate) is added, microwave-assisted hydrolysis is carried out at 155°C for 8 min and at 175°C for 16 min, the microwave power is 250 W, after the reaction, the temperature is cooled to below 40°C, poured into ice water, the pH is adjusted to 9 using 20% sodium hydroxide aqueous solution, extracted with ethyl acetate, washed with saturated sodium bicarbonate aqueous solution, 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine in sequence, dried with anhydrous sodium sulfate, concentrated under reduced pressure, recrystallized with a mixture of n-heptane and ethyl acetate (volume ratio 5:1), decolorized with activated carbon to obtain 4'-chloro-2-aminobiphenyl.
[0033] Example 3 S1, p-dichlorobenzene is added to a solvent (dichloromethane, 10 mL / g of p-dichlorobenzene), sulfur trioxide-pyridine complex is added under the condition of stirring at a speed of 350 rpm, the addition is completed within 2 h, the temperature is controlled below 10°C, after the addition is completed, the temperature is warmed to 42.5°C, the reaction is carried out at a stirring speed of 350 rpm for 2.5 h, after the reaction is cooled to 0°C, thionyl chloride is added, the addition is completed within 1 h, the molar ratio of p-dichlorobenzene, sulfur trioxide-pyridine complex and thionyl chloride is 1:1.05:1.8, the reaction is carried out at a stirring speed of 350 rpm at 40°C under reflux for 1.75 h, the temperature is cooled to below 5°C, the reaction is quenched using a mixture of ice ethanol and ice water (volume ratio 3:1), extracted with dichloromethane, washed with saturated sodium bicarbonate, 5% citric acid aqueous solution and saturated brine in sequence, dried with anhydrous magnesium sulfate, concentrated under reduced pressure to obtain 2,5-dichlorobenzenesulfonyl chloride; S2, 2,5-dichlorobenzenesulfonyl chloride is dissolved in a solvent (methyltetrahydrofuran and water, volume ratio 3:1, 15 mL / g of 2,5-dichlorobenzenesulfonyl chloride), aniline hydrochloride and 10% sodium bicarbonate aqueous solution are added in 3 batches under the condition of stirring at a speed of 300 rpm, the molar ratio of 2,5-dichlorobenzenesulfonyl chloride, aniline hydrochloride and sodium bicarbonate is 1:1.1:1.5, the temperature is controlled below 5°C during the addition, after the addition is completed, the temperature is warmed to 25°C, the reaction is carried out at a stirring speed of 275 rpm for 4.5 h, after the reaction, the reaction solution is poured into ice water to quench the reaction, extracted with ethyl acetate, washed with saturated sodium bicarbonate aqueous solution and saturated brine in sequence, dried with anhydrous magnesium sulfate, concentrated under reduced pressure to obtain 2,5-dichloro-N-phenylbenzenesulfonamide; S3, 2, 5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube and hydrogen peroxide in a molar ratio of 1:1.2:0.008:2. 2, 5-dichloro-N-phenylbenzenesulfonamide, cysteine and titanium dioxide nanotube are mixed, a solvent (water and ethanol in a mass ratio of 4:1, 12 mL / g of 2, 5-dichloro-N-phenylbenzenesulfonamide) is added, the titanium dioxide nanotube is pre-dispersed by ultrasonic, three vacuum-nitrogen cycles are performed, under the protection of nitrogen atmosphere, the photocatalysis is started, the photocatalysis wavelength is 360-370 nm, the light intensity is 90 mW / cm 2 After the reaction is completed, the reaction solution is cooled to 30°C, 30% hydrogen peroxide aqueous solution (pre-cooled to 5°C) is added, the addition time is 35 min, the reaction solution is stirred at 250 rpm in the dark for 2 h, a mixture of 10% sodium thiosulfate aqueous solution and ice water in a volume ratio of 1:1 is used to quench the reaction, ethyl acetate is used for extraction, and the obtained solution is sequentially washed with saturated sodium bicarbonate aqueous solution, 5% sodium thiosulfate aqueous solution (pH 8.5), 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain 2-chloro-6H-dibenzothiazine dioxide; S4, 2-chloro-6H-dibenzothiazine dioxide, zinc powder and p-toluenesulfonic acid in a molar ratio of 1:5:3, and glacial acetic acid in an amount of 8 mL / g of 2-chloro-6H-dibenzothiazine dioxide. 2-chloro-6H-dibenzothiazine dioxide, zinc powder and glacial acetic acid are mixed, stirred at 400 rpm, and heated to 80°C for reaction in the dark for 1 h. After cooling to 25°C, filtration is performed, and the obtained intermediate is concentrated under reduced pressure. The intermediate and p-toluenesulfonic acid are mixed, a solvent (triglyme, 5 mL / g of the intermediate) is added, and microwave-assisted hydrolysis is performed at 150°C for 10 min and at 170°C for 18 min, with a microwave power of 300 W. After the reaction, the solution is cooled to below 40°C, poured into ice water, and the pH is adjusted to 9 using 20% sodium hydroxide aqueous solution. Ethyl acetate is used for extraction, and the obtained solution is sequentially washed with saturated sodium bicarbonate aqueous solution, 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine, dried over anhydrous sodium sulfate, concentrated under reduced pressure, recrystallized from a mixture of n-heptane and ethyl acetate in a volume ratio of 5:1, and decolorized with activated carbon to obtain 4'-chloro-2-aminobiphenyl.
[0034] Example 4 Example 4 is based on Example 3, and the difference between Example 4 and Example 3 is that in Example 4, the temperature is controlled to be below 10°C when the sulfur trioxide-pyridine complex is added in step S1 of Example 4, and after the addition is completed, the temperature is increased to 30°C, and the reaction is stirred at 200 rpm for 4 h.
[0035] Example 5 Example 5 is based on Example 3, the difference between Example 5 and Example 3 is only that in Example 5, the temperature is controlled below 10°C when adding sulfur trioxide-pyridine complex in step S1, and after the addition is completed, the temperature is raised to 55°C, and the reaction is stirred at a speed of 500 rpm for 1 h.
[0036] Example 6 Example 6 is based on Example 3, the difference between Example 6 and Example 3 is only that in Example 6, after adding thionyl chloride in step S1, the reaction is stirred at a speed of 250 rpm at 30°C for 2.5 h.
[0037] Example 7 Example 7 is based on Example 3, the difference between Example 7 and Example 3 is only that in Example 7, after adding thionyl chloride in step S1, the reaction is stirred at a speed of 450 rpm at 50°C for 1 h.
[0038] Example 8 Example 8 is based on Example 3, the difference between Example 8 and Example 3 is only that in Example 8, the solvent in step S2 is replaced by tetrahydrofuran and dichloromethane in a volume ratio of 1:3.
[0039] Example 9 Example 9 is based on Example 3, the difference between Example 9 and Example 3 is only that in Example 9, when adding aniline hydrochloride and sodium bicarbonate solution in step S2, the temperature is controlled below 5°C, after the addition is completed, the temperature is raised to 15°C, and the reaction is stirred at a speed of 200 rpm for 6 h.
[0040] Example 10 Example 10 is based on Example 3, the difference between Example 10 and Example 3 is only that in Example 10, when adding aniline hydrochloride and sodium bicarbonate solution in step S2, the temperature is controlled below 5°C, after the addition is completed, the temperature is raised to 35°C, and the reaction is stirred at a speed of 450 rpm for 3 h.
[0041] Example 11 Example 11 is based on Example 3, the difference between Example 11 and Example 3 is only that in Example 11, the molar ratio of 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube, and hydrogen peroxide in step S3 is 1:1.2:0.004:2.
[0042] Example 12 Example 12 is based on Example 3, the difference between Example 12 and Example 3 is only that in Example 12, the molar ratio of 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube, and hydrogen peroxide in step S3 is 1:1.2:0.015:2.
[0043] Example 13 Example 13 is based on Example 3, the difference between Example 13 and Example 3 is only that in Example 13 the photo-catalytic condition in Step S3 is wavelength 360-370 nm, light intensity 80 mW / cm 2 .
[0044] Example 14 Example 14 is based on Example 3, the difference between Example 14 and Example 3 is only that in Example 14 the photo-catalytic condition in Step S3 is wavelength 360-370 nm, light intensity 100 mW / cm 2 .
[0045] Example 15 Example 15 is based on Example 3, the difference between Example 15 and Example 3 is only that in Example 15 the photo-catalytic reaction condition in Step S3 is stirring at 350 rpm for 8 h at 40 °C.
[0046] Example 16 Example 16 is based on Example 3, the difference between Example 16 and Example 3 is only that in Example 16 the photo-catalytic reaction condition in Step S3 is stirring at 550 rpm for 6 h at 60 °C.
[0047] Example 17 Example 17 is based on Example 3, the difference between Example 17 and Example 3 is only that in Example 17 the temperature of hydrogen peroxide solution in Step S3 is 20 °C, the adding time is 50 min, and stirring at 150 rpm for 3 h in dark.
[0048] Example 18 Example 18 is based on Example 3, the difference between Example 18 and Example 3 is only that in Example 18 the temperature of hydrogen peroxide solution in Step S3 is 40 °C, the adding time is 20 min, and stirring at 350 rpm for 1 h in dark.
[0049] Example 19 Example 19 is based on Example 3, the difference between Example 19 and Example 3 is only that in Example 19 the solvent in Step S4 is replaced by 1,4-dioxane.
[0050] Example 20 Example 20 is based on Example 3, the difference between Example 20 and Example 3 is only that in Example 20 the microwave-assisted hydrolysis condition in Step S4 is 15 min at 140 °C, then 25 min at 160 °C, and the microwave power is 400 W.
[0051] Example 21 Example 21 is based on Example 3, the difference between Example 21 and Example 3 is only that the conditions of microwave-assisted hydrolysis in step S4 in Example 20 are 5 min at 160°C, 12 min at 185°C, and the microwave power is 200 W.
[0052] Comparative Example 1 Comparative Example 1 is based on Example 3, the difference between Comparative Example 1 and Example 3 is only that the photocatalytic system in step S3 in Comparative Example 1 is replaced by a sodium sulfide and sulfur powder catalytic system.
[0053] S1, p-dichlorobenzene is added to a solvent (dichloromethane, 10 mL / g of p- dichlorobenzene), and sulfur trioxide-pyridine complex is added under stirring at a speed of 350 rpm, and the addition is completed within 2 h, the temperature is controlled below 10°C, after the addition is completed, the temperature is raised to 40°C, and the reaction is stirred at a speed of 300 rpm for 3 h, after cooling to 0°C, thionyl chloride is added, the addition is completed within 1 h, the molar ratio of p-dichlorobenzene, sulfur trioxide-pyridine complex and thionyl chloride is 1:1.05:1.8, the reaction is refluxed at 35°C and stirred at a speed of 300 rpm for 2 h, and then cooled to below 5°C, an ice ethanol and ice water mixture with a volume ratio of 3:1 is used to quench the reaction, dichloromethane is used for extraction, and saturated sodium bicarbonate, 5% citric acid aqueous solution and saturated brine are used for washing in sequence, anhydrous magnesium sulfate is used for drying, and after concentration under reduced pressure, 2,5-dichlorobenzenesulfonyl chloride is obtained; S2, 2,5-dichlorobenzenesulfonyl chloride is dissolved in a solvent (methyltetrahydrofuran and water with a volume ratio of 3:1, 15 mL / g of 2,5-dichlorobenzenesulfonyl chloride), and aniline hydrochloride and 10% sodium bicarbonate aqueous solution are added in 3 batches under stirring at a speed of 300 rpm, the molar ratio of 2,5-dichlorobenzenesulfonyl chloride, aniline hydrochloride and sodium bicarbonate is 1:1.1:1.5, the temperature is controlled below 5°C during the addition, after the addition is completed, the temperature is raised to 20°C, and the reaction is stirred at a speed of 250 rpm for 5 h, after the reaction, the reaction solution is poured into ice water to quench the reaction, ethyl acetate is used for extraction, saturated sodium bicarbonate aqueous solution and saturated brine are used for washing in sequence, anhydrous magnesium sulfate is used for drying, and after concentration under reduced pressure, 2,5-dichloro-N-phenylbenzenesulfonamide is obtained; S3, 2, 5-dichloro-N-phenylbenzenesulfonamide, sodium sulfide, sulfur powder and hydrogen peroxide in a molar ratio of 1:2.5:0.3:1.5. 2, 5-dichloro-N-phenylbenzenesulfonamide was added into N-methylpyrrolidone (12 mL / g of 2, 5-dichloro-N-phenylbenzenesulfonamide), sulfur powder and sodium sulfide were added in turn, after three vacuum-nitrogen cycles, the reaction was stirred at 400 rpm under nitrogen atmosphere at 170°C for 7 h in the dark, cooled to 80°C, 30% hydrogen peroxide aqueous solution was added, stirred at 300 rpm for 1 h, cooled to 25°C, the reaction solution was poured into ice water, extracted with ethyl acetate, washed with 5% citric acid aqueous solution, saturated sodium bicarbonate aqueous solution, 5% sodium thiosulfate aqueous solution (pH 8.5) and saturated brine in turn, dried with anhydrous magnesium sulfate, concentrated under reduced pressure to obtain 2-chloro-6H-dibenzothiazine dioxide; S4, 2-chloro-6H-dibenzothiazine dioxide, zinc powder and p-toluenesulfonic acid in a molar ratio of 1:5:3, the amount of glacial acetic acid was 8 mL / g of 2-chloro-6H-dibenzothiazine dioxide. 2-chloro-6H-dibenzothiazine dioxide, zinc powder and glacial acetic acid were mixed and stirred at 400 rpm, the reaction was carried out at 80°C for 1 h in the dark, cooled to 25°C, filtered and concentrated under reduced pressure to obtain an intermediate; the intermediate and p-toluenesulfonic acid were mixed, a solvent (triglyme, 5 mL / g of the intermediate) was added, microwave-assisted hydrolysis was carried out at 145°C for 12 min and at 165°C for 20 min, the microwave power was 350 W, after the reaction, the reaction solution was cooled to below 40°C, poured into ice water, the pH was adjusted to 9 with 20% sodium hydroxide aqueous solution, extracted with ethyl acetate, washed with saturated sodium bicarbonate aqueous solution, 1% ethylenediaminetetraacetic acid disodium salt aqueous solution (pH 8.5) and saturated brine in turn, dried with anhydrous sodium sulfate, concentrated under reduced pressure, recrystallized with a mixture of n-heptane and ethyl acetate (volume ratio 5:1), decolorized with activated carbon to obtain 4'-chloro-2-aminobiphenyl.
[0054] Performance detection test The mass and purity of the sample were detected, and the total yield and purity were calculated.
[0055] Table 1 shows the detection results of the total yield and purity of the product Detection results Total yield (%) Purity (%) Example 1 51.2 99.4 Example 2 50.6 99.2 Example 3 54.4 99.7 Example 4 47.8 99.5 Example 5 46.9 97.4 Example 6 48.2 99.3 Example 7 45.3 96.8 Example 8 46.6 98.4 Example 9 47.2 99.6 Example 10 46.5 94.1 Example 11 43.7 97.6 Example 12 48.2 98.9 Example 13 48.5 99.0 Example 14 49.2 97.7 Example 15 49.5 99.6 Example 16 48.3 96.9 Example 17 49.8 99.7 Example 18 45.6 93.4 Example 19 39.7 91.2 Example 20 47.1 98.6 Example 21 48.5 95.4 Comparative Example 1 35.3 85.7 As shown in Table 1, the total yield of Examples 1-3 is greater than 50.6%, and the purity is greater than 99.2%, so it can be seen that the preparation process of the present application has high yield and purity while improving greenness and economy.
[0056] From Table 1, it can be seen that the difference between Examples 4-7 and Example 3 is only that the reaction conditions after the addition of sulfur trioxide-pyridine complex in Examples 4 and 5, and the reaction conditions after the addition of thionyl chloride in Examples 6 and 7 are destroyed, and the performance is decreased; this is because the reaction temperature and time will affect the selectivity and conversion rate of the reaction, thereby affecting the yield and purity.
[0057] From Table 1, it can be seen that the difference between Example 8 and Example 3 is only that the solvent in step S2 is replaced by tetrahydrofuran and dichloromethane with a volume ratio of 1:3 in Example 8, and the performance of Example 8 is decreased compared with Example 3; this is because the solubility of the nucleophile is decreased, and the reaction rate is affected, thereby the yield and purity are decreased.
[0058] From Table 1, it can be seen that the difference between Examples 9 and 10 and Example 3 is only that the reaction rate and reaction time of step S2 are changed in Examples 9 and 10, and the performance of Examples 9 and 10 is decreased compared with Example 3; this is because the destruction of the optimal conditions will affect the reaction rate and selectivity, and the mass transfer process is affected.
[0059] From Table 1, it can be seen that the difference between Examples 11 and 12 and Example 3 is only that the molar ratio of 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotube and hydrogen peroxide in step S3 is changed in Examples 11 and 12, and the performance of Example 11 is decreased compared with Example 3; this is because too much or too little titanium dioxide nanotube will affect the generation of free radicals and the subsequent reaction process, thereby affecting the yield and purity.
[0060] From Table 1, it can be seen that the difference between Examples 13-18 and Example 3 is only that the light intensity during photocatalysis is changed in Examples 13 and 14, the temperature, stirring rate and time of photocatalytic reaction are changed in Examples 15 and 16, and the reaction conditions after the addition of hydrogen peroxide solution are changed in Examples 17 and 18, and the performance of Examples 13-18 is decreased compared with Example 3; this is because the defined optimal condition range is destroyed, the photocatalytic reaction efficiency is affected, by-products are easily produced or the catalyst activity is decreased, thereby affecting the reaction process, and the yield and purity are affected.
[0061] From Table 1, it can be seen that the difference between Examples 19-21 and Example 3 is only that the solvent of step S4 is replaced by 1,4-dioxane in Example 19, 1,4-dioxane is prone to ring-opening reaction, which makes the hydrolysis in step S4 incomplete, and the yield and purity are decreased; the conditions of microwave-assisted hydrolysis are changed in Examples 20 and 21, which affects the hydrolysis, and thereby the yield and purity are decreased.
[0062] As can be seen from Table 1, the difference between Comparative Example 1 and Example 3 is that the photocatalytic system in step S3 in Comparative Example 1 is replaced by a traditional sodium sulfide and sulfur powder system. Compared with Example 3, the performance of Comparative Example 1 is obviously decreased. This is because the sodium sulfide and sulfur powder system needs high-temperature reaction, the side reaction increases, the yield decreases, and the impurities increase.
[0063] The specific embodiments are only illustrative of the application, and are not intended to limit the application. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the application. The technical scope of the application is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims
1. A method for preparing 4'-chloro-2-aminobiphenyl, characterized in that: The following steps are involved: S1. Add p-dichlorobenzene to a solvent, add sulfur trioxide-pyridine complex under stirring, heat and stir to react after the addition is complete, cool, add thionyl chloride, heat and stir to reflux to react, cool, quench the reaction, extract, wash, dry, and concentrate to obtain 2,5-dichlorobenzenesulfonyl chloride; S2, dissolving 2,5-dichlorobenzenesulfonyl chloride in a solvent, adding aniline hydrochloride and sodium bicarbonate solution under stirring, heating and stirring to react after completion of the addition, quenching the reaction, extracting, washing, drying, and concentrating to obtain 2,5-dichloro-N-phenylbenzenesulfonamide; S3, mixing 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine and titanium dioxide nanotubes, adding a solvent, turning on the photocatalytic reaction under a protective atmosphere, heating and stirring to react, cooling after the reaction is completed, adding a hydrogen peroxide solution and stirring to react in the dark, quenching the reaction, extracting, washing, drying and concentrating to obtain 2-chloro-6H-dibenzothiazine dioxide; S4. Mix 2-chloro-6H-dibenzothiazine dioxide, zinc powder and glacial acetic acid, heat and stir to react in the dark, cool, filter, and concentrate under reduced pressure to obtain an intermediate; mix the intermediate with p-toluenesulfonic acid, add a solvent, and perform microwave-assisted hydrolysis. After the reaction, cool, adjust the pH to alkaline, extract, wash, dry, concentrate, and recrystallize to obtain 4'-chloro-2-aminobiphenyl.
2. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 1, wherein: When adding the sulfur trioxide-pyridine complex in step S1, the temperature is controlled below 10° C. After the addition is completed, the temperature is raised to 40-45° C. and the mixture is stirred at 300-400 rpm for 2-3 hours.
3. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 2, wherein: In step S1, after adding thionyl chloride, the mixture is stirred and refluxed at 35-45° C. and 300-400 rpm for 1.5-2 hours.
4. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 1, wherein: The solvent in step S2 includes methyltetrahydrofuran and water.
5. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 4, wherein: In step S2, the temperature is controlled below 5° C. when adding aniline hydrochloride and sodium bicarbonate solution. After the addition is complete, the temperature is raised to 20-30° C. and stirred at 250-300 rpm for 4-5 hours.
6. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 1, wherein: In step S3, the molar ratio of 2,5-dichloro-N-phenylbenzenesulfonamide, cysteine, titanium dioxide nanotubes and hydrogen peroxide is 1:1.2:(0.006-0.01):
2.
7. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 6, wherein: The photocatalytic conditions in step S3 are a wavelength of 360-370 nm and a light intensity of 85-95 mW / cm².
8. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 7, wherein: The photocatalytic reaction conditions in step S3 are as follows: stirring the reaction at 400-500 rpm at 45-55° C. for 6.5-7.5 hours; the hydrogen peroxide solution is added at a temperature of 25-35° C. for 30-40 minutes, and stirred at 200-300 rpm for 1.5-2.5 hours in the dark.
9. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 1, wherein: The solvent in step S4 includes triethylene glycol dimethyl ether.
10. The method for preparing 4'-chloro-2-aminobiphenyl according to claim 9, wherein: The conditions for microwave-assisted hydrolysis in step S4 are as follows: reaction at 145-155° C. for 8-12 min, heating to 165-175° C. for 16-20 min, and microwave power of 250-350 W.