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Construction and application of 2, 6-dibromopyridine oxidation system

A technology of dibromopyridine and oxidation system, applied in the direction of organic chemistry and the like, can solve the problems of serious environmental pollution, a large amount of waste water, expensive reagents, etc., and achieves the effects of good catalytic activity, reduced corrosion, and reduced synthesis cost.

Active Publication Date: 2020-04-28
ZHEJIANG GONGSHANG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But the solvent used in this method is trifluoroacetic acid, the reagent is expensive, and trifluoroacetic acid has strong acidity, not only strict requirements are placed on the equipment during the reaction, acid waste liquid will be produced after the reaction, a large amount of waste water will also be produced when the product is processed, and the environment will be polluted. serious

Method used

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  • Construction and application of 2, 6-dibromopyridine oxidation system
  • Construction and application of 2, 6-dibromopyridine oxidation system
  • Construction and application of 2, 6-dibromopyridine oxidation system

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preparation example Construction

[0033] The preparation method of each ionic liquid used in the present invention can operate with reference to the preparation method of catalyst in "Chemical Engineering Journal" 2011,172, specifically as follows:

[0034] One, the preparation of N,N-dimethylbenzylaminopropanesulfonic acid trifluoroacetic acid ionic liquid is:

[0035] Weigh 12.2g (0.1mol) of 1,3-propane sultone into a 100mL reaction flask, then add 50mL of ethyl acetate, stir evenly, cool the reaction system to 0°C, and drop 13.5 g (0.1mol) N,N-dimethylbenzylamine, continue to stir for 30 minutes after the dropwise addition, then raise the temperature to 60°C, and stir at constant temperature for 2 hours. Finish the reaction, suction filter, wash the filter cake, and dry to obtain white solid N,N-dimethylbenzylaminopropanesulfonate. Take 25.8g (0.1mol) N,N-dimethylbenzylaminopropanesulfonate and dissolve it in 60mL deionized water, N 2 Slowly add 11.4 g (0.1 mol) of trifluoroacetic acid dropwise to the sol...

Embodiment 1

[0039]Add 3g (0.0125mol) 2,6 dibromopyridine, 25g N,N-dimethylbenzylaminotrifluoroacetic acid ionic liquid, 5.7g 30% (0.05mol) hydrogen peroxide, 0.15 g cerium trifluoromethanesulfonate, reacted at 90°C for 4h, cooled to room temperature; added chloroform to the reaction system for extraction (20mL×3 times), combined the organic phases, and used 5% NaHCO 3 Solution (about 10 mL) washed the organic phase with water, and the organic phase was distilled to remove chloroform to obtain an off-white solid, recrystallized from methanol, and the white needle-like crystals obtained were N-dibromopyridine oxide (that is, N-oxide-2,6- Dibromopyridine), the yield is 83.6%. The water layer (ionic liquid aqueous solution) was dewatered under reduced pressure to obtain the ionic liquid, which was dried in vacuum (i.e., 75°C (1×10 -4 Pa) Vacuum dried overnight) and then applied.

Embodiment 2-9

[0041] The cerium trifluoromethanesulfonate in Example 1 was changed to the metal trifluoromethanesulfonate salt as described in Table 1 below, and the dosage remained unchanged, and the rest were the same as in Example 1.

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Abstract

The invention discloses a construction method of a 2, 6-dibromopyridine oxidation system. The construction method comprises the following steps: using 2, 6-dibromopyridine as a reaction substrate, andorming an acidic ionic liquid and 2, 6-dibromopyridine into a mixed solution; adding hydrogen peroxide into the mixed solution, and adding trifluoromethanesulfonic acid metal salt to form the 2, 6-dibromopyridine oxidation system. The invention also provides a method for preparing N-oxide-2, 6-dibromopyridine by using the 2, 6-dibromopyridine oxidation system. The method comprises the following steps: heating the 2, 6-dibromopyridine oxidation system to a reaction temperature of 60-110 DEG C, and reacting for 2-8 hours to obtain the N-oxide-2, 6-dibromopyridine. The pyridine oxidation systemimproves the reaction efficiency, reduces the corrosion of strong acid to equipment, and reduces the synthesis cost as the solvent can be repeatedly used after the reaction.

Description

technical field [0001] The invention relates to the technical field of pyridine oxidation, in particular to a sulfonate-containing trifluoroacetic acidic ionic liquid, a preparation method thereof, and an application of the ionic liquid in a pyridine oxidation system. Background technique [0002] Pyridine compounds are important fine chemical raw materials, mainly used in pesticides, medicines, feed additives and other fields, and have potential application value in the synthesis of functional small molecules. The commonly used method for pyridine oxidation is to use trifluoroacetic acid as the solvent, with H 2 o 2 As an oxidant, the oxidation of pyridine is carried out, and the molar ratio of hydrogen peroxide to 2,6-dibromopyridine is about 3:1. But the solvent used in this method is trifluoroacetic acid, the reagent is expensive, and trifluoroacetic acid has strong acidity, not only strict requirements are placed on the equipment during the reaction, acid waste liquid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/89C07D213/73
CPCC07D213/73C07D213/89
Inventor 韩晓祥蔡锦旺蔡哲王晴周祐昇端木佳辉汪思田
Owner ZHEJIANG GONGSHANG UNIVERSITY