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Method for fast and selectively nitrifying meta-xylene through microwave radiation

A technology of m-xylene and microwave radiation is applied in the field of organic nitration, which can solve the problems of poor nitrification selectivity and long time consumption, and achieve the effects of saving time, improving selectivity and being easy to control.

Inactive Publication Date: 2015-11-11
HEFEI NORMAL UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention provides a method for rapid and selective nitration of m-xylene by microwave radiation, so as to overcome the problems of poor nitration selectivity and long time consumption of m-xylene nitration method in the prior art

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Under the condition of magnetic stirring, 4 mL of 1,2-dichloroethane, 2.0 mmol of m-xylene, 3.0 mmol of acetic anhydride, 1 mmol of Bi(NO 3 ) 3 ·5H 2 O and zeolite molecular sieve catalyst Hβ(500) 0.10g, after microwave heating for 30s, add 5mL water to the reaction mixture to stop the reaction, filter to remove the catalyst, the organic phase is successively washed with 10mL water, 10mL NaHCO with a mass fraction of 5% 3 Wash with 10mL of water and let stand to separate the organic phase. Gas chromatographic analysis was performed using p-nitrotoluene as an internal standard. The results showed that the yield was 53.4%, of which 4-nitro-m-xylene accounted for 92.8%, 2-nitro-m-xylene accounted for 7.2%, and the 4- / 2-ratio reached 12.9. The zeolite molecular sieve catalyst Hβ(500) described in the above step (1) can be replaced by any one of Hβ(25), Hβ(150) or Hβ(280).

Embodiment 2

[0021] Under magnetic stirring conditions, 8 mL of 1,2-dichloroethane, 4.0 mmol of m-xylene, 9.0 mmol of acetic anhydride, 3 mmol of Bi(NO 3 ) 3 ·5H 2 O and zeolite molecular sieve catalyst Hβ(500) 0.50g, after microwave heating for 180s, add 8mL water to the reaction mixture to stop the reaction. 3 Wash with 10mL of water and let stand to separate the organic phase. Gas chromatographic analysis was performed using p-nitrotoluene as an internal standard. The results showed that the yield was 51.8%, of which 4-nitro-m-xylene accounted for 93.2%, 2-nitro-m-xylene accounted for 6.8%, and the 4- / 2-ratio reached 13.7.

Embodiment 3

[0023] Under the condition of magnetic stirring, 6 mL of 1,2-dichloroethane, 3.0 mmol of m-xylene, 6.0 mmol of acetic anhydride, 2 mmol of Bi(NO 3 ) 3 ·5H 2 O and zeolite molecular sieve catalyst Hβ(500) 0.30g, after microwave heating for 105s, add 7mL water to the reaction mixture to stop the reaction, after filtering to remove the catalyst, the organic phase was successively washed with 10mL water, 10mL NaHCO with a mass fraction of 5%. 3 Wash with 10mL of water and let stand to separate the organic phase. Gas chromatographic analysis was performed using p-nitrotoluene as an internal standard. The results showed that the yield was 55.8%, of which 4-nitro-m-xylene accounted for 93%, 2-nitro-m-xylene accounted for 7%, and the 4- / 2-ratio reached 13.3.

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Abstract

The invention relates to a method for fast and selectively nitrifying meta-xylene through microwave radiation. The method comprises the following steps of under the magic stirring, adding 4 to 8ml of chloroform into a round bottom flask; then, sequentially adding 2.0 to 4.0 mmol of meta-xylene, 3.0 to 9.0 mmol of acetic anhydride, 1.0 to 3.0 mmol of Bi(NO3)3 5H2O and 0.10 to 0.50g of zeolite molecular sieve catalysts Hbeta (500); stopping the reaction after the microwave heating for 30 to 180s; removing the catalysts through filtering; performing gas phase color spectrum analysis after the dewatering drying. A microwave technology is applied to the meta-xylene nitrifying process; the reaction process is greatly accelerated; the reaction selectivity is effectively improved; the yield reaches 56.3 percent at the 60s; the 4- / 2- ratio reaches 18.2. The method has the advantages that the operation is easy; the energy is saved; the efficiency is high; the control is easy; the method belongs to a green environment-friendly meta-xylene nitrifying method.

Description

technical field [0001] The invention belongs to the field of organic matter nitration, and in particular relates to a method for rapid and selective nitration of m-xylene by microwave radiation. Background technique [0002] Nitro-m-xylene is an important intermediate of pesticides, dyes, medicines and photosensitive materials, which is mainly produced by nitration of m-xylene. The nitrating reagents used in the nitration method mainly include nitric acid, nitric acid sulfuric acid, nitric acid anhydride system and nitrates. Among them, the nitration of the nitrating reagent nitrate avoids the use of strong corrosive acids, has a good application prospect, and has been favored by researchers. extensive attention. However, this method currently has problems such as long time required for nitrification, poor selectivity, and high production cost. [0003] At present, the commonly used heating method is to heat from the surface of the object first, and then the heat is transf...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C205/06C07C201/08
Inventor 董雄辎田燕卫艳新彭新华司圣柱王丽平
Owner HEFEI NORMAL UNIV
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