CN117623931A

CN117623931A - Preparation method of safe and environment-friendly mono-nitro aromatic hydrocarbon

Info

Publication number: CN117623931A
Application number: CN202311384776.3A
Authority: CN
Inventors: 王力; 贾逸雄; 赵万胜; 李世云; 李兴存; 文彬; 陈兴权
Original assignee: Qingyuan Innovation Laboratory
Current assignee: Qingyuan Innovation Laboratory
Priority date: 2023-10-24
Filing date: 2023-10-24
Publication date: 2024-03-01

Abstract

A preparation method of safe and environment-friendly mono-nitro aromatic hydrocarbon comprises the steps of taking aromatic hydrocarbon as a raw material in polyphosphoric acid, utilizing a reaction system formed by nitrifying reagents, stirring for 3-8 hours at room temperature until the reaction is completed, finally adding water to quench the reaction, and extracting the product by an organic solvent, washing, drying, filtering, concentrating and purifying to obtain the mono-nitro aromatic hydrocarbon compound; the method has the advantages of simple synthesis method, simple post-reaction treatment method, mild and safe reaction conditions, wide substrate application range, almost quantitatively completed reaction and the like, accords with the development concept of green chemistry, and provides a new thought and method for large-scale industrialized preparation of the mono-nitroaromatic hydrocarbon.

Description

Preparation method of safe and environment-friendly mono-nitro aromatic hydrocarbon

Technical Field

The invention belongs to the field of fine chemical engineering, and particularly relates to a safe and environment-friendly preparation method of mononitroaromatic hydrocarbon.

Background

As an important organic intermediate, the mononitroaromatic compound has great application in the fields of perfume, medicine, pesticide, explosive, material and the like, and the preparation method of the safe and environment-friendly mononitroaromatic compound is always one of important research directions in the chemical industry.

At present, the preparation method of the mononitroaromatic hydrocarbon commonly adopted in the industry is realized by a mixed acid system of concentrated nitric acid and concentrated sulfuric acid, but the method involves a plurality of problems, such as large production of a large amount of waste acid, high environmental protection pressure, easy volatilization of the concentrated nitric acid, poor production environment, high equipment requirement, too severe reaction process, higher risk coefficient of the nitration technology, easy occurrence of polynitrolation reaction, difficult separation and purification and the like. Particularly, with the increasing legal requirements of the state on environmental protection and the importance of chemical safety production in recent years, the application space of the mixed acid nitration system is further compressed, and a safe and environment-friendly mononitration method has become an urgent need in the chemical industry.

Chinese patent CN104744311a reports the preparation of 2-nitro-4-chlorophenol from 4-chlorophenol as a starting material using 60% nitric acid as a nitrating agent. The concentrated nitric acid is used in the nitration system, which directly causes the problems of poorer production environment, higher equipment requirement and the like of the working procedure, and water is generated in the nitration system besides the nitration product, so that the unreacted concentrated nitric acid is diluted, and the reaction is influenced; in addition, the nitrifying system has a low yield for nitrifying relatively inactive aromatic hydrocarbons (aromatic hydrocarbons containing only electron withdrawing groups).

Zolfigol et al reported the use of N ₂ O ₄ Method for nitrating phenol as nitrating reagent (Synthetic Communications,2008,38 (19), 336-3374), which method first consists in adding N ₂ O ₄ Soaking on polyethylene glycol, and then preparing polyethylene glycol-N ₂ O ₄ (PEG-N ₂ O ₄ ) The system is used for the nitration of phenol. PEG-N at room temperature ₂ O ₄ The system can directly nitrify phenol to obtain mononitrophenol and dinitrophenol with medium to high yield. At PEG-N ₂ O ₄ In the nitrifying system, the whole nitrifying process has the advantages of mild reaction, slow heat release and the like, but N ₂ O ₄ The gas has extremely toxic and anesthetic toxicity to human nervous system, and N is not excluded in the industrialized reaction process ₂ O ₄ The risk of gas leakage, which obviously does not conform to the production concept of safety and environmental protection.

Haghnazari reports a nitration system using ferric nitrate as a nitration reagent (International Nano Letters,2011,1 (1), 30-33.) which reacts at room temperature for 10min with ethyl acetate as a solvent and silica as a catalyst to obtain mononitroaromatic hydrocarbons with higher yield. However, the nitration method is remarkable only for aromatic hydrocarbons containing electron donating groups, but is not excellent for aromatic hydrocarbons containing electron withdrawing groups; in addition, ferric nitrate is an inorganic oxidant, and is easy to burn when being mixed with organic matters, so that the actual production process is limited to a certain extent.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a safe and environment-friendly preparation method of mononitroaromatic hydrocarbon.

The invention adopts the following technical scheme:

a process for preparing the safe and environment-friendly mononitro aromatic hydrocarbon includes such steps as preparing polyphosphoric acid, stirring at room temp for 3-8 hr by nitrifying reagent, adding water quenching reaction, extracting by organic solvent, washing, drying, filtering, concentrating and purifying.

Further, the nitrifying reagent is sodium nitrate, potassium nitrate, zinc nitrate or ferric nitrate.

Further, the addition amount of the nitrifying agent is 1 to 1.5 equivalents.

Further, the aromatic hydrocarbon is a compound containing an electron donating group, an electron withdrawing group or both an electron donating group and an electron withdrawing group.

Further, the aromatic hydrocarbon is 4-fluorophenol, 4-fluorobenzoic acid, 4-chlorophenol, 4-chloroanisole, terephthalyl ether, 2-chloro-4-fluoroanisole, 3-fluoro-4-hydroxybenzaldehyde, benzoic acid, 4-bromobenzaldehyde, benzonitrile or benzotrifluoride.

The organic solvent is dichloroethane.

As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

firstly, the innovation of the invention is mainly characterized in that the price of the nitrifying reagent-potassium nitrate is cheaper, the nitrifying reagent-potassium nitrate is harmless to human body and easy to store; the selected protonic acid solvent-polyphosphoric acid can dissolve low-molecular and high-molecular compounds; the acidity of the polyphosphoric acid is weaker than that of nitric acid and sulfuric acid, and stronger than that of acetic acid, and the polyphosphoric acid has no oxidizing ability and small toxicity to human bodies;

secondly, the method has the advantages of simple synthesis method, simple post-reaction treatment method, mild and safe reaction conditions, wide substrate application range, almost quantitative completion of the reaction and the like, accords with the development concept of green chemistry, and provides a new thought and method for large-scale industrialized preparation of the mononitroaromatic hydrocarbon.

Drawings

FIG. 1 is a synthetic roadmap of the invention

FIG. 2 is a synthetic route diagram of 2-nitro-4-fluorophenol;

FIG. 3 is a GC spectrum of 4-fluorophenol;

FIG. 4 is a GC spectrum of the 4-fluorophenol nitration reaction liquid;

FIG. 5 is a GC spectrum of a standard sample of 2-nitro-4-fluorophenol;

FIG. 6 is a synthetic route diagram of 3-nitro-4-fluorobenzoic acid;

FIG. 7 is a GC spectrum of 4-fluorobenzoic acid;

FIG. 8 is a GC spectrum of the 4-fluorobenzoic acid nitration reaction liquid;

FIG. 9 is a GC spectrum of a standard sample of 3-nitro-4-fluorobenzoic acid;

FIG. 10 is a synthetic route diagram of 4-chloro-2-nitrophenol;

FIG. 11 is a GC spectrum of 4-chlorophenol;

FIG. 12 is a GC diagram of a 4-chlorophenol nitration reaction liquid;

FIG. 13 is a GC spectrum of a standard sample of 4-chloro-2-nitrophenol;

FIG. 14 is a synthetic route diagram of 4-chloro-2-nitroanisole;

FIG. 15 is a GC spectrum of 4-chloroanisole;

FIG. 16 is a GC spectrum of a 4-anisole nitration reaction liquid;

FIG. 17 is a GC spectrum of a standard sample of 4-chloro-2-nitroanisole;

FIG. 18 is a synthetic route diagram of 1, 4-dimethoxy-2-nitrobenzene;

FIG. 19 is a GC spectrum of terephthalyl ether;

FIG. 20 is a GC spectrum of a liquid para-xylylene ether nitrating reaction;

FIG. 21 is a GC spectrum of a 1, 4-dimethoxy-2-nitrobenzene standard sample;

FIG. 22 is a synthetic route diagram of 1-chloro-5-fluoro-2-methoxy-3-nitrobenzene;

FIG. 23 is a GC spectrum of 2-chloro-4-fluoroanisole;

FIG. 24 is a GC spectrum of a 2-chloro-4-fluoroanisole nitration reaction liquid;

FIG. 25 is a GC spectrum of a standard sample of 1-chloro-5-fluoro-2-methoxy-3-nitrobenzene;

FIG. 26 is a synthetic route diagram of 3-fluoro-4-hydroxy-5-nitrobenzene;

FIG. 27 is a GC spectrum of 3-fluoro-4-hydroxybenzaldehyde;

FIG. 28 is a GC spectrum of a 3-fluoro-4-hydroxybenzaldehyde nitration reaction liquid;

FIG. 29 is a GC spectrum of a 3-fluoro-4-hydroxy-5-nitrobenzene standard sample;

FIG. 30 is a synthetic route diagram of 3-nitrobenzoic acid;

FIG. 31 is a GC spectrum of benzoic acid;

FIG. 32 is a GC spectrum of a benzoic acid nitration reaction liquid;

FIG. 33 is a GC spectrum of a 3-nitrobenzoic acid standard sample;

FIG. 34 is a diagram of the synthesis of 4-bromo-3-nitrobenzaldehyde;

FIG. 35 is a GC spectrum of 4-bromobenzaldehyde;

FIG. 36 is a GC spectrum of a 4-bromobenzaldehyde nitration reaction liquid;

FIG. 37 is a GC spectrum of a standard sample of 4-bromo-3-nitrobenzaldehyde;

FIG. 38 is a synthetic route diagram of 3-nitrobenzonitrile;

FIG. 39 is a GC spectrum of benzonitrile;

FIG. 40 is a GC spectrum of a benzonitrile nitration reaction liquid;

FIG. 41 is a GC spectrum of a 3-nitrobenzonitrile standard sample;

FIG. 42 is a synthetic route diagram of 3-nitrobenzotrifluoride;

FIG. 43 is a GC spectrum of benzotrifluoride;

FIG. 44 is a GC spectrum of the benzotrifluoride nitration reaction liquid;

FIG. 45 is a GC spectrum of a 3-nitrobenzotrifluoride standard sample;

FIG. 46 is a GC spectrum of a 4-fluorophenol nitration (potassium nitrate-acetic acid nitration system) reaction fluid;

FIG. 47 is a GC diagram of a reaction solution of 4-fluorophenol nitrification (potassium nitrate-concentrated sulfuric acid nitrification system).

Detailed Description

The invention is further described below by means of specific embodiments.

A preparation method of safe and environment-friendly mono-nitro aromatic hydrocarbon comprises the steps of taking aromatic hydrocarbon as a raw material in polyphosphoric acid, utilizing a reaction system formed by nitrifying reagents, stirring for 3-8 hours at room temperature until the reaction is completed, finally adding water to quench the reaction, extracting the product with dichloroethane, washing with water, drying with anhydrous sodium sulfate, filtering, rotary steaming, and purifying to obtain the mono-nitro aromatic hydrocarbon compound; the synthetic route is referred to in fig. 1.

Wherein the nitrifying reagent is sodium nitrate, potassium nitrate, zinc nitrate or ferric nitrate; specifically, the addition amount of the nitrifying agent is 1 to 1.5 equivalents.

The aromatic hydrocarbon is a compound containing an electron donating group, an electron withdrawing group or both an electron donating group and an electron withdrawing group; specifically, the aromatic hydrocarbon is 4-fluorophenol, 4-fluorobenzoic acid, 4-chlorophenol, 4-chloroanisole, terephthalyl ether, 2-chloro-4-fluoroanisole, 3-fluoro-4-hydroxybenzaldehyde, benzoic acid, 4-bromobenzaldehyde, benzonitrile or benzotrifluoride.

Example 1

The synthetic route of the preparation method of 2-nitro-4-fluorophenol is shown in figure 2.

The specific method comprises the following steps:

500mg of 4-fluorophenol is taken in a 100ml three-mouth bottle, 542mg of potassium nitrate is added, a proper amount of PPA is added, the reaction is carried out for 4 hours under mechanical stirring, the reaction is finished, 80ml of water is added dropwise for quenching reaction after the reaction liquid is cooled to room temperature, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying, filtering and rotary evaporation of filtrate are carried out, and the product is obtained, and the yield is 100% by GC detection. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, figures 3, 4 and 5 are GC spectrograms of the 4-fluorophenol, the 4-fluorophenol nitration reaction liquid and the 2-nitro-4-fluorophenol standard sample respectively.

Example 2

The synthetic route of the preparation method of 3-nitro-4-fluorobenzoic acid is shown in figure 6.

The specific method comprises the following steps:

500mg of 4-fluorobenzoic acid is taken in a 100ml three-mouth bottle, 433mg of potassium nitrate is added, a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, 80ml of water is added dropwise for quenching reaction after the reaction liquid is cooled to room temperature, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtration are carried out, the filtrate is subjected to rotary evaporation to obtain a product, and the yield is 76.0% after GC detection, namely the 3-nitro-4-fluorobenzoic acid. The GC temperature-rising program is kept for 2min at the initial temperature of 180 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, fig. 7, fig. 8 and fig. 9 are GC spectra of 4-fluorobenzoic acid, 4-fluorobenzoic acid nitration reaction liquid and 3-nitro-4-fluorobenzoic acid standard sample, respectively.

Example 3

The synthetic route of the preparation method of 4-chloro-2-nitrophenol is shown in FIG. 10.

The specific method comprises the following steps:

500mg of 4-chlorophenol is taken in a 100ml three-mouth bottle, 472mg of potassium nitrate is added, a proper amount of PPA is added, the reaction is carried out for 3 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is added for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtering are carried out, the filtrate is subjected to rotary evaporation to obtain a product, and the yield is determined to be 4-chloro-2-nitrophenol through GC detection, wherein the yield is 98.9%. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 11, FIG. 12 and FIG. 13 are GC spectra of 4-chlorophenol, 4-chlorophenol nitration reaction liquid and 4-chloro-2-nitrophenol standard sample, respectively.

Example 4

The synthetic route of the preparation method of 4-chloro-2-nitroanisole is shown in figure 14.

The specific method comprises the following steps:

500mg of 4-anisole is taken in a 100ml three-mouth bottle, 425mg of potassium nitrate is added, then a proper amount of PPA is added, the reaction is carried out for 3 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is dripped for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtering are carried out, the filtrate is subjected to rotary evaporation to obtain the product, and the yield is determined to be 4-chloro-2-nitroanisole through GC detection, wherein the yield is 95.1%. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, figure 15, figure 16 and figure 17 are GC spectrograms of the 4-anisole, the 4-anisole nitration reaction liquid and the 4-chloro-2-nitroanisole standard sample respectively.

Example 5

The synthetic route of the preparation method of 1, 4-dimethoxy-2-nitrobenzene is shown in FIG. 18.

The specific method comprises the following steps:

500mg of paraphthaloyl ether is taken in a 100ml three-mouth bottle, 439mg of potassium nitrate is added, a proper amount of PPA is added, the reaction is carried out for 3 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is added for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtering are carried out, the filtrate is subjected to rotary evaporation to obtain a product, and the yield is determined to be 1, 4-dimethoxy-2-nitrobenzene through GC detection, wherein the yield is 100.0%. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 19, FIG. 20 and FIG. 21 are GC spectra of the standard sample of terephthalyl ether, the nitrifying reaction liquid of terephthalyl ether and 1, 4-dimethoxy-2-nitrobenzene respectively.

Example 6

The synthetic route of the preparation method of 1-chloro-5-fluoro-2-methoxy-3-nitrobenzene is shown in FIG. 22.

The specific method comprises the following steps:

500mg of 2-chloro-4-fluoroanisole is taken in a 100ml three-mouth bottle, 378mg of potassium nitrate is added, then a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is dripped for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing is carried out, anhydrous sodium sulfate is dried, filtration is carried out, the filtrate is subjected to rotary evaporation, and the product is obtained, and is determined to be 1-chloro-5-fluoro-2-methoxy-3-nitrobenzene through GC detection, and the yield is 94.6%. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, figure 23, figure 24 and figure 25 are GC spectrograms of 2-chloro-4-fluoroanisole, 2-chloro-4-fluoroanisole nitration reaction liquid and 1-chloro-5-fluoro-2-methoxy-3-nitrobenzene standard sample respectively.

Example 7

The synthetic route of the preparation method of 3-fluoro-4-hydroxy-5-nitrobenzaldehyde is shown in FIG. 26.

The specific method comprises the following steps:

500mg of 3-fluoro-4-hydroxybenzaldehyde is taken in a 100ml three-mouth bottle, 433mg of potassium nitrate is added, then a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is dripped for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing is carried out, anhydrous sodium sulfate is dried, filtration is carried out, and the filtrate is subjected to rotary evaporation to obtain the product, and the yield of the 3-fluoro-4-hydroxy-5-nitrobenzaldehyde is determined to be 92.6 percent through GC detection. The GC temperature-rising program is kept for 2min at the initial temperature of 180 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 27, FIG. 28 and FIG. 29 are the GC spectra of 3-fluoro-4-hydroxybenzaldehyde, 3-fluoro-4-hydroxybenzaldehyde nitration reaction liquid and 3-fluoro-4-hydroxy-5-nitrobenzene standard samples, respectively.

Example 8

The synthetic route of the preparation method of 3-nitrobenzoic acid is shown in FIG. 30.

The specific method comprises the following steps:

500mg of benzoic acid is taken in a 100ml three-mouth bottle, 497mg of potassium nitrate is added, a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is added for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtering are carried out, the filtrate is subjected to rotary evaporation to obtain the product, and the yield is determined to be 3-nitrobenzoic acid by GC detection, and is 98.0%. The GC temperature-rising program is kept for 2min at the initial temperature of 180 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 31, FIG. 32 and FIG. 33 are GC spectra of benzoic acid, benzoic acid nitration reaction liquid and 3-nitrobenzoic acid standard sample, respectively.

Example 9

The synthetic route of the preparation method of 4-bromo-3-nitrobenzaldehyde is shown in FIG. 34.

The specific method comprises the following steps:

500mg of 4-bromobenzaldehyde is taken in a 100ml three-mouth bottle, 327mg of potassium nitrate is added, then a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, 80ml of water is added dropwise for quenching reaction after the reaction liquid is cooled to room temperature, dichloroethane is added for extraction, water washing, anhydrous sodium sulfate drying, filtration and rotary evaporation of filtrate are carried out, the product is obtained, and the yield is determined to be the 4-bromo-3-nitrobenzaldehyde through GC detection, wherein the yield is 100%. The GC temperature-rising program is kept for 2min at the initial temperature of 180 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 35, FIG. 36 and FIG. 37 are the GC spectra of the 4-bromobenzaldehyde, the 4-bromobenzaldehyde nitration reaction liquid and the 4-bromo-3-nitrobenzaldehyde standard sample, respectively.

Example 10

The synthetic route of the preparation method of 3-nitrobenzonitrile is shown in FIG. 38.

The specific method comprises the following steps:

500mg of benzonitrile is taken in a 100ml three-mouth bottle, 588mg of potassium nitrate is added, then a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is added for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtration are carried out, the filtrate is subjected to rotary evaporation to obtain the product, and the yield is determined to be 3-nitrobenzonitrile through GC detection, and is 98.5%. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 39, FIG. 40 and FIG. 41 are GC spectra of the benzonitrile, the benzonitrile nitration reaction liquid and the 3-nitrobenzonitrile standard sample, respectively.

Example 11

The synthetic route of the preparation method of 3-nitrobenzotrifluoride is shown in FIG. 42.

The specific method comprises the following steps:

500mg of benzotrifluoride is taken in a 100ml three-mouth bottle, 415mg of potassium nitrate is added, a proper amount of PPA is added, the reaction is carried out for 8 hours under mechanical stirring, the reaction is finished, the reaction liquid is cooled to room temperature, 80ml of water is added for quenching reaction, dichloroethane is added for extracting the reaction liquid, water washing, anhydrous sodium sulfate drying and filtering are carried out, the filtrate is subjected to rotary evaporation to obtain the product, and the yield is determined to be the 3-nitrobenzotrifluoride by GC detection, and is 96.2%. The GC temperature-rising program is kept for 2min at the initial temperature of 80 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein, FIG. 43, FIG. 44 and FIG. 45 are GC spectra of benzotrifluoride, benzotrifluoride nitration reaction liquid and 3-nitrobenzotrifluoride standard sample, respectively.

In order to examine the inventive aspects of the present invention, the present invention also successively attempted the preparation of 2-nitro-4-fluorophenol in example 1 using a potassium nitrate-acetic acid nitration system and a potassium nitrate-concentrated sulfuric acid nitration system.

Comparative example 1

The specific method comprises the following steps:

500mg of 4-fluorophenol is respectively taken in two 100ml three-mouth bottles, 542mg of potassium nitrate and acetic acid with the same volume are respectively added, two reactions are stirred for 8 hours at room temperature, the reaction is finished, the two reaction liquids are respectively poured into 80ml of water, dichloroethane is added for extracting the reaction liquids, water washing, anhydrous sodium sulfate drying, filtration and rotary evaporation of the filtrate are carried out, and the content of the 2-nitro-4-fluorophenol is detected by GC. The GC temperature program was maintained at an initial temperature of 150deg.C for 2min, a temperature rise step of 15deg.C/min to the end of the temperature rise time, and FIG. 46 is a GC spectrum of the mononitration reaction of the prepared p-4-fluorophenol, with a yield of 16.8%.

Comparative example 2

The specific method comprises the following steps:

500mg of 4-fluorophenol is respectively taken in two 100ml three-mouth bottles, 542mg of potassium nitrate and concentrated sulfuric acid with the same volume are respectively added, two reactions are stirred for 8 hours at room temperature, the reaction is finished, the two reaction liquids are respectively poured into 80ml of water, dichloroethane is added for extraction, water washing, anhydrous sodium sulfate drying, filtration and rotary evaporation of filtrate are carried out, and the content of the 2-nitro-4-fluorophenol is detected by GC. The GC temperature-rising program is kept for 2min at the initial temperature of 150 ℃ and the temperature-rising step is 15 ℃/min until the temperature-rising time is finished.

Wherein FIG. 47 is a GC spectrum of mononitration of the prepared p-4-fluorophenol with a yield of 97.6%.

As can be seen from a comparison of example 1 with comparative examples 1-2, the present application takes polyphosphoric acid as a proton acid solvent to participate in the nitration reaction.

According to the method, from aromatic hydrocarbon, potassium nitrate is used as a nitrifying reagent, polyphosphoric acid is used as a reaction solvent, and nitration reaction is carried out at room temperature so as to prepare mononitroaromatic hydrocarbon; the method has the advantages of simple synthesis method, simple post-reaction treatment method, mild and safe reaction conditions, wide substrate application range, almost quantitatively completed reaction and the like, accords with the development concept of green chemistry, and provides a new thought and method for large-scale industrialized preparation of the mononitroaromatic hydrocarbon.

The foregoing description is only illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, i.e., the invention is not to be limited to the details of the claims and the description, but rather is to cover all modifications which are within the scope of the invention.

Claims

1. A preparation method of safe and environment-friendly mono-nitro aromatic hydrocarbon is characterized by comprising the following steps: in polyphosphoric acid, aromatic hydrocarbon is used as a raw material, a reaction system consisting of nitrifying reagents is utilized, stirring is carried out for 3-8 hours at room temperature until the reaction is completed, finally, water quenching reaction is added, and the product is extracted by an organic solvent, washed by water, dried, filtered, concentrated and purified, thus obtaining the mono-nitro aromatic hydrocarbon compound.

2. The method for preparing safe and environment-friendly mono-nitroaromatic hydrocarbon according to claim 1, which is characterized in that: the nitrifying reagent is sodium nitrate, potassium nitrate, zinc nitrate or ferric nitrate.

3. The method for preparing safe and environment-friendly mono-nitroaromatic hydrocarbon according to claim 2, which is characterized in that: the addition amount of the nitrifying reagent is 1-1.5 equivalents.

4. The method for preparing safe and environment-friendly mono-nitroaromatic hydrocarbon according to claim 3, which is characterized in that: the synthetic route is as follows:

5. the method for preparing safe and environment-friendly mono-nitroaromatic hydrocarbon according to claim 1, which is characterized in that: the aromatic hydrocarbon is a compound containing an electron donating group, an electron withdrawing group or both an electron donating group and an electron withdrawing group.

6. The method for preparing safe and environment-friendly mono-nitroaromatic hydrocarbon according to claim 5, which is characterized in that: the aromatic hydrocarbon is 4-fluorophenol, 4-fluorobenzoic acid, 4-chlorophenol, 4-anisole, terephthalyl ether, 2-chloro-4-fluoroanisole, 3-fluoro-4-hydroxybenzaldehyde, benzoic acid, 4-bromobenzaldehyde, benzonitrile or benzotrifluoride.

7. The method for preparing safe and environment-friendly mono-nitroaromatic hydrocarbon according to claim 1, which is characterized in that: the organic solvent is dichloroethane.