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High-selectivity synthesis method of 4-nitro-ortho-xylene

A nitro-ortho-xylene, high-selectivity technology, applied in the preparation of nitro compounds, organic chemistry, etc., can solve the problems of unsustainable development, failure to meet its needs, low atom economy, etc. Effects of engineering use, improving atom utilization, improving reaction yield and selectivity

Active Publication Date: 2013-10-09
绍兴贝斯美化工股份有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] With the development of environmental economy, the shortcomings of the above methods are becoming more and more manifested, mainly as follows: (1) The atom economy is not high; (2) The reaction selectivity is poor; (3) A large amount of waste acid and waste water are produced during the reaction process ; (4) The process of recycling nitric acid mixed acid consumes a lot of energy
In view of the increasing demand for 4-nitro-ortho-xylene, traditional production methods have been unable to meet its demand, and a method for highly selective synthesis of 4-nitro-ortho-xylene is urgently needed to replace
With the development of environmental economy, the traditional production method of 4-nitro-o-xylene is not sustainable and must be replaced by more environmentally friendly methods

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] In a 100 mL one-necked flask, add o-xylene (0.53 g, 5.0 mmol), methanesulfonic acid (0.48 g, 5.0 mmol), nitrogen dioxide (1.84 g, 40.0 mmol), stir magnetically, and store at -50 °C After reacting for 10 h, the reaction was terminated with saturated sodium bicarbonate solution (5 mL), and m-nitrotoluene (0.10 g) was added as an internal standard. Dichloromethane (5 mL×3) was extracted three times, the organic phases were combined, washed with water until neutral, and dried over anhydrous sodium sulfate. Gas chromatographic analysis was carried out, and the content of each component was calculated by the internal standard method.

[0023] The remaining mass of o-xylene was 0.05 g, and the conversion rate was 91%. The quality of 4-nitro-o-xylene and 3-nitro-o-xylene is 0.39g, and the yield rate is 52%, wherein the mass of 4-nitro-o-xylene is 0.29 g, and the mass fraction is 74%; 3-nitro-o-xylene The mass of o-xylene is 0.10 g, and the mass fraction is 26%.

Embodiment 2

[0025] In a 100 mL one-necked flask, add o-xylene (0.53 g, 5.0 mmol), sulfuric acid (0.25 g, 2.5 mmol), nitrogen dioxide (0.91 g, 19.8 mmol), stir magnetically, and react at 0°C for 10 h , the reaction was terminated with saturated sodium bicarbonate solution (5 mL), and m-nitrotoluene (0.10 g) was added as an internal standard. Dichloromethane (5 mL×3) was extracted three times, the organic phases were combined, washed with water until neutral, and dried over anhydrous sodium sulfate. Gas chromatographic analysis was carried out, and the content of each component was calculated by the internal standard method.

[0026] The remaining mass of o-xylene was 0.03 g, and the conversion rate was 94%. The mass of 4-nitro-o-xylene and 3-nitro-o-xylene is 0.32g, and the yield is 43%, wherein the mass of 4-nitro-o-xylene is 0.24 g, and the mass fraction is 75%; 3-nitro-o-xylene The mass of o-xylene is 0.08 g, and the mass fraction is 25%.

Embodiment 3

[0028] In a 100 mL one-necked flask, add o-xylene (0.53 g, 5.0 mmol), trifluoroacetic acid (0.06 g, 0.5 mmol), nitrogen dioxide (1.84 g, 40.0 mmol), magnetically stir, and react at -50 °C After 10 h, the reaction was terminated with saturated sodium bicarbonate solution (5 mL), and m-nitrotoluene (0.10 g) was added as an internal standard. Dichloromethane (5 mL×3) was extracted three times, the organic phases were combined, washed with water until neutral, and dried over anhydrous sodium sulfate. Gas chromatographic analysis was carried out, and the content of each component was calculated by the internal standard method.

[0029] The remaining mass of o-xylene was 0.08 g, and the conversion rate was 85%. The mass of 4-nitro-o-xylene and 3-nitro-o-xylene is 0.35g, and the yield rate is 46%, wherein the mass of 4-nitro-o-xylene is 0.24 g, and the mass fraction is 69%; 3-nitro-o-xylene The mass of o-xylene is 0.11 g, and the mass fraction is 31%.

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Abstract

The invention relates to a high-selectivity synthesis method of 4-nitro-ortho-xylene. The 4-nitro-ortho-xylene is highly selectively synthesized from ortho-xylene (serving as a basic raw material) in the presence of a catalyst and a nitration reagent (which is nitrogen dioxide instead of nitro-sulfuric acid). The method provided by the invention comprises the following steps of: adding the ortho-xylene and the catalyst into a reactor; adding the nitrogen dioxide into the reactor, and then magnetically stirring the mixture for complete reaction; and after the reaction is ended, terminating the reaction by using a saturated sodium bicarbonate solution and carrying out extraction. By adopting the synthesis method provided by the invention, the yield and the selectivity of the reaction can be obviously improved by the catalyst added in the reaction process; and the synthesis method provided by the invention is mild in reaction condition, good in selectivity, high in yield and applicable to engineering application.

Description

technical field [0001] The invention relates to a method for synthesizing 4-nitro-ortho-xylene, in particular to a method for synthesizing 4-nitro-ortho-xylene with nitrogen dioxide nitration with high selectivity by using ortho-xylene as a raw material. Background technique [0002] 4-Nitro-o-xylene and 3-nitro-o-xylene are two isomers of mononitro-o-xylene. They are very important chemical intermediates and are widely used in dyes, medicines, plastics , rubber additives, rust removal, sterilization and plant growth regulators, etc. Among them, 4-nitro-o-xylene is an intermediate of the new herbicide N-methalin, vitamin B2 and 3,4-dimethylaniline, and its market demand is much greater than that of 3-nitro-o-xylene. [0003] At present, the industrial production of 4-nitro-o-xylene at home and abroad mainly adopts the traditional method of nitric acid and sulfuric acid mixed acid for nitration. Using ortho-xylene as raw material, a crude mixture containing 4-nitro-ortho-xy...

Claims

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Application Information

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IPC IPC(8): C07C205/06C07C201/08
Inventor 彭新华唐波魏松波单洪亮任纪纲田园
Owner 绍兴贝斯美化工股份有限公司
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