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Preparation method of 2-methyl-4-nitrophenylamine

A technology for nitroaniline and o-toluidine, which is applied in the field of organic compound synthesis, can solve the problems of many side reactions, consumption of large alkali solution, and high requirements for reaction conditions, and achieves reduction of the generation of by-products and the discharge of waste acid. , the effect of easy operation

Inactive Publication Date: 2010-07-14
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Adopt p-toluenesulfonyl chloride method, more auxiliary materials, complicated process, and p-toluenesulfonyl chloride price is higher, and production cost is bigger
Using formic acid for acylation, the ability of acylating agent is weak, the requirements for reaction conditions are high, and there are many side reactions, and the use of concentrated sulfuric acid as a solvent for nitration produces a large amount of acid-containing wastewater, which is difficult to treat
Use acetic anhydride and mixed acid for nitration. Acetic anhydride is a precursor drug and the price is high. The reaction produces a large amount of acetic acid, which cannot be recycled. Afterwards, it is nitrated with mixed acid. The post-treatment process requires a large amount of lye, high production costs, and more waste water.

Method used

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  • Preparation method of 2-methyl-4-nitrophenylamine
  • Preparation method of 2-methyl-4-nitrophenylamine

Examples

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Effect test

Embodiment 1

[0025] Example 1. A method for preparing 2-methyl-4-nitroaniline, using o-methylaniline as a starting material, the following steps are carried out in sequence:

[0026] (1) Add 45g (0.75mol) of acetic acid to a 250ml three-necked flask, add 32.1g (0.3mol) o-methylaniline dropwise, and control the feeding temperature not to exceed 60°C. After the dripping is completed, the temperature is raised to 100°C to react, and the generated water is continuously evaporated during the reaction, and the reaction is stopped after 4 hours.

[0027] (2) 32g (0.33mol) concentrated nitric acid (65%, Wt%, the same below) was slowly dropped into the reaction solution obtained in the above step (1), and the process was cooled by a water bath to keep the temperature below 30°C. Then, react at a constant temperature at 30°C for 5h; after the reaction is completed, pour the reaction solution into cold water at 10°C to precipitate a yellow solid, filter and dry to obtain a nitrated solid.

[0028] (3) Add ...

Embodiment 2

[0030] Example 2. A preparation method of 2-methyl-4-nitroaniline, using o-methylaniline as a starting material, the following steps were carried out in sequence:

[0031] (1) Add 45g (0.75mol) of acetic acid to a 250ml three-necked flask, add 32.1g (0.3mol) o-methylaniline dropwise, and control the feeding temperature not to exceed 60°C. After the dripping is completed, the temperature is raised to 100°C to react, and the generated water is continuously evaporated during the reaction, and the reaction is stopped after 4 hours.

[0032] (2) 32 g (0.33 mol) of concentrated nitric acid (65%) was slowly dropped into the above reaction liquid, and during the dropping process, it was cooled in an ice water bath, and the feeding temperature was controlled not to exceed 10°C. Then react at a constant temperature at 10°C for 5 hours. After the reaction is completed, the reaction solution is poured into cold water at 10°C to precipitate a yellow solid, which is filtered and dried to obtain ...

Embodiment 3

[0035] Example 3. A method for preparing 2-methyl-4-nitroaniline, using o-methylaniline as a starting material, the following steps were carried out in sequence:

[0036] (1) Add 45g (0.75mol) of acetic acid to a 250ml three-necked flask, add 32.1g (0.3mol) o-methylaniline dropwise, and control the feeding temperature not to exceed 60°C. After the dripping is completed, the temperature is raised to 100°C to react, and the generated water is continuously evaporated during the reaction, and the reaction is stopped after 4 hours.

[0037] (2) 32g (0.33mol) of concentrated nitric acid (65%) was slowly dropped into the above reaction liquid, and the water bath was cooled during the dropping process, and the feeding temperature was controlled not to exceed 40°C. Then react at a constant temperature at 40°C for 5 hours. After the reaction is completed, the reaction solution is poured into cold water at 10°C to precipitate a yellow solid, which is filtered and dried to obtain a nitrated so...

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Abstract

The invention discloses a preparation method of 2-methyl-4-nitrophenylamine, which sequentially comprises the following steps of: (1) protecting acylation amino group by using ortho-toludiene as a raw material and using acetic acid as an acylation agent; (2) carrying out nitrification reaction on the reaction liquid obtained in the step (1) by using concentrated nitric acid as a nitrifying agent to obtain a nitrified solid; (3) carrying out hydrolysis reaction on the nitrified solid by using concentrated hydrochloric acid as a hydrolysis reagent; and (4) regulating the pH of the reaction liquid obtained in the step (3) to1-2, and filtering and recrystallizing an obtained filter cake to obtain the 2-methyl-4-nitrophenylamine. The 2-methyl-4-nitrophenylamine prepared by using the method has the characteristics of concise process and low cost.

Description

Technical field [0001] The invention relates to a method for synthesizing organic compounds, in particular to a method for synthesizing 2-methyl-4-nitroaniline (2-methyl-4-nitroaniline). Background technique [0002] 2-methyl-4-nitroaniline, its molecular formula is C 7 H 8 N 2 O 2 Its structure is as shown in S-1. The pure product is yellow-green crystals with a melting point of 130-131°C. It is a medium-to-high grade ice-dyed dye. It is an indispensable dye for dyeing velveteen, golden velvet, and corduroy. [0003] [0004] According to comprehensive literature reports, the current preparation of 2-methyl-4-nitroaniline adopts the following methods: 1. It is reported in the reports PB74027 and PB25625 of the US Federal Government Publishing Bureau that o-toluidine is used as raw material and p-toluenesulfonyl chloride is used as acylation. It is obtained by acylation, nitration, hydrolysis, neutralization and filtration and drying, with a yield of 95.0%; 2. Using o-methylaniline...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/62
Inventor 陈新志阮建成钱超
Owner ZHEJIANG UNIV
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