A method for preparing 2-acetylpyrazine by electrolysis

A technology of acetylpyrazine and electrolysis, which is applied in the direction of electrolysis components, electrolysis process, electrolysis organic production, etc., can solve the problems of easy change of product properties, reduction of product purity, and low product quality, so as to avoid the use of metal catalysts, The effect of high product purity and controllable reaction process

Active Publication Date: 2022-03-22
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Silver salts are generally used as noble metal salts, which have good effects in the synthesis of 2-acetylpyrazine, but still do not change the disadvantages of high cost and difficult recovery
For non-precious metal salts, ferrous salts are generally used, which are cheap and high in yield, but in actual production, there are many by-products, which are difficult to separate and reduce the purity of the product.
At the same time, if the ferrous salt in the product is not removed, the product properties are easy to change and the product quality is low

Method used

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  • A method for preparing 2-acetylpyrazine by electrolysis
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  • A method for preparing 2-acetylpyrazine by electrolysis

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preparation example Construction

[0031] The relevant electrochemical reaction equation of the preparation method of 2-acetylpyrazine of the present invention is as follows:

[0032] anode:

[0033] 2H 2 O→4H + o 2 +4e -

[0034] cathode:

[0035]

[0036] The generated sulfate radicals participate in the following reactions:

[0037]

[0038] The specific steps of using the device are as follows:

[0039] First, solvent dichloromethane, pyrazine, pyruvic acid, water, ammonium persulfate are added to the cathode chamber, then dimethyl sulfoxide is added, the DC power supply 1 is turned on, and then the first magnetic stirrer 71 is turned on, and the first stirring bar 61 starts Rotate to mix the raw materials, add sulfuric acid solution in the anode chamber, then turn on the second magnetic stirrer 72, the second stirrer 62 starts to rotate, the cation exchange membrane 8 separates the anion and yang chambers, and only NH 4 + and H + Through, a complete current path is formed. The above-mentio...

Embodiment 1

[0041] The H-type electrolytic cell is used as the reactor, the anode is plated with ruthenium-titanium plate, the cathode is lead plate, and the anode chamber and the cathode chamber are separated by cation exchange membrane Nafion PFSA Membranes (N-324).

[0042] Dissolve 0.067 mol of pyrazine and 0.033 mol of pyruvic acid in dichloromethane and dilute to 100 mL, take 100 mL of saturated ammonium persulfate solution, add the above solution into the cathode chamber, and then add 5 g of dimethyl sulfoxide. The substance molar ratio of the pyrazine and pyruvic acid is 2:1, and the concentration of the pyruvic acid dissolved in methylene chloride is 0.33mol L -1 , the concentration of oxidant ammonium persulfate dissolved in water is 1.5mol L -1 , the quality of the dimethyl sulfoxide is 2% of the total mass of the pyrazine / pyruvate solution and the ammonium persulfate solution in the cathode chamber.

[0043] Add 200mL of sulfuric acid solution with a mass fraction of 20% in t...

Embodiment 2

[0045] The H-type electrolytic cell is used as the reactor, the anode is plated with ruthenium-titanium plate, the cathode is lead plate, and the anode chamber and the cathode chamber are separated by cation exchange membrane Nafion PFSA Membranes (N-324).

[0046] Dissolve 0.033 mol of pyrazine and 0.033 mol of pyruvic acid in dichloromethane and set the volume to 100 mL, take 100 mL of saturated ammonium overflow acid solution, add the above solution into the cathode chamber, and then add 5 g of dimethyl sulfoxide.

[0047] The molar ratio of the pyrazine and pyruvic acid substance is 1:1, and the concentration of the pyruvic acid dissolved in methylene chloride is 0.33mol L -1 , the concentration of oxidant ammonium persulfate dissolved in water is 1.5mol L -1 , the quality of the dimethyl sulfoxide is 2% of the total mass of the pyrazine / pyruvate solution and the ammonium persulfate solution in the cathode chamber;

[0048] Add 200mL of sulfuric acid solution with a mass ...

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Abstract

The invention discloses a method for preparing 2-acetylpyrazine by electrolysis, comprising the following steps: using an H-type electrolytic cell as a reactor, dissolving pyrazine and pyruvic acid in dichloromethane, and dissolving oxidant ammonium persulfate in water , into the cathode chamber, and then add dimethyl sulfoxide; add sulfuric acid solution with a mass fraction of 5-30% in the anode chamber; keep constant temperature, power on and electrolyze, and keep the current density at 10-800A m ‑2 , the energized amount reaches 2F·mol ‑1 Stop energizing afterward, separate organic phase, obtain the dichloromethane solution that contains 2-acetylpyrazine; The present invention solves the high production cost, the low product quality and the Technical problems of polluting the environment.

Description

technical field [0001] The invention belongs to the technical field of fine chemical industry and organic electrochemical synthesis, and specifically relates to a method for preparing 2-acetylpyrazine by electrolysis. Background technique [0002] Acetylpyrazine is a widely used food additive and pharmaceutical intermediate. At present, the preparation method is mainly organometallic reagent method, pyrazinamide is dehydrated into corresponding nitrile, reacted with Grignard reagent methylmagnesium bromide, and then hydrolyzed to obtain acetylpyrazine, the biggest disadvantage of which is that the reaction must be carried out at low temperature And the cost is high. In order to reduce costs, people try to activate the method of ammonium persulfate with transition metal salts, and transition metal salts are divided into noble metal salts and non-noble metal salts. Silver salts are generally used as noble metal salts, which have good effects when synthesizing 2-acetylpyrazin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25B3/09C25B3/05C25B9/19C25B9/01
CPCC25B3/00
Inventor 毛麟张新胜钮东方
Owner EAST CHINA UNIV OF SCI & TECH
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