Synthesis method of diethyl azodicarboxylate and intermediate of diethyl azodicarboxylate

A technology of diethyl azodicarboxylate and diethyl hydrogen azodicarboxylate is applied in the preparation of hydrazide, organic chemistry, etc., can solve problems such as environmental pollution, and achieves good economy, wide reaction temperature range, and operation. simple effect

Active Publication Date: 2013-01-30
SHANDONG NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method saves the cost to a certain extent, and the intensity of the reaction is slowed down, but it is e

Method used

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  • Synthesis method of diethyl azodicarboxylate and intermediate of diethyl azodicarboxylate
  • Synthesis method of diethyl azodicarboxylate and intermediate of diethyl azodicarboxylate

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Embodiment 1

[0042] In a 500ml three-necked flask equipped with mechanical stirring, 250ml of diethyl carbonate was added, and 125g of hydrazine hydrate with a mass percentage of 80% was added. Heated to reflux in an oil bath for 4 hours, distilled off excess diethyl carbonate, and the remaining mixed solution was spin-dried under reduced pressure to obtain crude ethyl carbazate. Recrystallize with acetone to obtain 198 g (95.2%) of pure ethyl carbazate.

[0043] II, the preparation of diethyl hydroazodicarboxylate

Embodiment 2

[0045] In a 250ml three-neck flask equipped with mechanical stirring, add 120ml of absolute ethanol, and add 4.8g of metallic sodium under nitrogen protection. After the metallic sodium is completely dissolved, add 31.2g of ethyl carbazate. After 0.5h, the solution turns orange red. Slowly add 40 g of diethyl carbonate dropwise. After the dropwise addition, react at room temperature for 6 hours to obtain an orange-red turbid liquid, and recover ethanol and diethyl carbonate by atmospheric distillation. Use 10% hydrochloric acid solution to adjust the pH to 6.0. White crystals are precipitated and washed with cold water to obtain the crude product diethyl hydroazodicarboxylate. Recrystallize the above crude product with acetone and petroleum ether to obtain a white solid hydrogenation Diethyl azodicarboxylate 6.6g (12.5%) mp=130-132℃.

[0046] 1 HNMR (CDCl 3 ,300MHz)δ(ppm):8.97(2H,s,NH);3.99-4.06(4H,m,CH 2 ); 1.16 (6H,t,CH 3 ).

Embodiment 3

[0048]In a 250ml three-neck flask equipped with mechanical stirring, add 120ml of absolute ethanol, and add 7.1g of sodium metal under nitrogen protection. After the sodium metal is completely dissolved, add 31.2g of ethyl carbazate. After 0.5h, the solution turns orange. red. Slowly add 40 g of diethyl carbonate dropwise. After the dropwise addition, react at 75° C. for 6 h to obtain an orange-red turbid liquid. Ethanol and diethyl carbonate are recovered by atmospheric distillation. Use a hydrochloric acid solution with a mass concentration of 20% to adjust the pH ≈ 5.0, white crystals precipitate, wash with cold water to obtain the crude product diethyl hydroazodicarboxylate, and recrystallize the above crude product with acetone and petroleum ether in turn to obtain a white solid hydrogenation Diethyl azodicarboxylate 26.6g (50.7%) mp=130-132°C.

[0049] 1 HNMR (CDCl 3 ,300MHz)δ(ppm):8.97(2H,s,NH);3.99-4.06(4H,m,CH 2 ); 1.16 (6H,t,CH 3 ).

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Abstract

The invention discloses a synthesis method of diethyl azodicarboxylate. The synthesis method comprises the following steps that (1) under the effect of sodium ethoxide, diethyl carbonate and ethyl carbazate are heated for reaction for 1 to 6 hours, the pH of solution is regulated to 3 to 8, white crystals are separated out, the recrystallization is carried out, and hydrogenated diethyl azodicarboxylate is obtained; and (2) the hydrogenated diethyl azodicarboxylate is added at minus 15 DEG C to 45 DEG C, in the acid solution, bromine or hydrobromic acid or sodium bromide and potassium bromide are used as catalysts, excessive hydrogen peroxide is dripped, the reaction is carried out for 1 to 10 hours, the extraction is carried out, organic solvents are removed through distillation, and saffron diethyl azodicarboxylate is obtained. The invention also provides a hydrogenated diethyl azodicarboxylate intermediate and a synthesis method of the hydrogenated diethyl azodicarboxylate intermediate. The synthesis method has the advantages that diethyl carbonate is used as raw materials, cleanness and environment protection are realized, no pollution exists, raw materials can be cyclically utilized, the economy is better, the operation is simple, the reaction temperature range is wide, the reaction is stable, the energy consumption is low, the yield is high, and the industrial production is favorably realized.

Description

technical field [0001] The invention relates to a synthesis method of diethyl azodicarboxylate and its intermediate. Background technique [0002] Azodicarboxylates are a class of compounds with both azo and carboxyl functional groups. Azodicarboxylate diesters have been widely used as multifunctional reagents in organic synthesis due to their unique electronic and structural properties. Especially in the Mitsunobu reaction, the ammoniation of carbonyl compounds, the ammoniation of unsaturated hydrocarbons and the synthesis of heterocyclic compounds, it plays a very important role. In addition, azodicarboxylate diester can also be used as an oxidant for the removal of alcohols and amines. Hydrogenation reaction. Diethyl azodicarboxylate (DEAD) is the main member of this class of reagents and can be used in the synthesis of photosensitizers, polymerization catalysts, fungicides and other products. In addition, diethyl azodicarboxylate is an important class of liquid foaming...

Claims

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Application Information

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IPC IPC(8): C07C245/04C07C241/04C07C243/28
Inventor 张志德吕硕陈玉琴张兴红
Owner SHANDONG NORMAL UNIV
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