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Preparation method of acetylpyrazine

A technology of acetylpyrazine and cyanopyrazine, applied in the direction of organic chemistry and the like, can solve the problems of complicated operation, danger, low boiling point of diethyl ether, etc., and achieve the effects of simple synthesis method, small loss of materials and high content of finished products

Inactive Publication Date: 2017-04-26
SHANDONG JITIAN AROMA CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the Grignard reaction has high requirements on the water control of the system, it must be dried again after each recovery of ether before it can be reused. The operation is cumbersome and difficult, and the energy consumption and material loss are relatively large.
At the same time, ether has a low boiling point, is extremely volatile, and has a wide explosion limit (1.9-36%), which is very dangerous

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A preparation method of acetylpyrazine, comprising the following steps:

[0021] 1) Fully mix 20g (0.19mol) of cyanopyrazine and 50g of anhydrous toluene to make a mixed solution for later use;

[0022] 2) Take a 1000g three-neck bottle, add 9g (0.37 mol) of magnesium chips into the bottle, then add 180g of anhydrous tetrahydrofuran, and inject methyl chloride at 20-50°C to make methylmagnesium chloride;

[0023] 3) Add 400g of anhydrous toluene, heat and distill to recover 170-180g of anhydrous tetrahydrofuran;

[0024] 4) Add all the mixed solution obtained in step 1) dropwise at 0-50°C after recovery, and keep warm for 2-3 hours after dropping;

[0025] 5) Add 150g of water dropwise for hydrolysis, neutralize with acetic acid to PH=5-6, then extract four times with 4×80g toluene, and get 15g of brownish-red crude product with a content of 97% after removing toluene;

[0026] 6) Add 15g of the crude product obtained in step 5), 50g of alcohol, and 2g of activated ca...

Embodiment 2

[0028] A preparation method of acetylpyrazine, comprising the following steps:

[0029] 1) Fully mix 40kg (0.38Kmol) of cyanopyrazine with 100L toluene to make a mixed solution for later use;

[0030] 2) Add 18kg of magnesium chips (0.74K mol) to the reaction kettle, then add 360kg of anhydrous tetrahydrofuran, and inject methyl chloride at 20~50°C to make methylmagnesium chloride;

[0031] 3) Add 800kg of anhydrous toluene, heat and distill to recover 340~360kg of anhydrous tetrahydrofuran;

[0032] 4) Add all the mixed solution obtained in step 1) dropwise at 0-50°C after recovery, and keep warm for 2-3 hours after dropping;

[0033] 5) Add 300 kg of water dropwise for hydrolysis, neutralize with 50~60kg of acetic acid to PH=5~6, extract with 4×160m toluene four times, and get 30kg of brownish red crude product after removing toluene, with a content of 95~97%;

[0034] 6) Add 30kg of the crude product obtained in step 5), 100kg of alcohol, and 4kg of activated carbon into ...

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Abstract

The invention discloses a preparation method of acetylpyrazine. Acetylpyrazine is prepared from 8-10 parts of magnesium chips, 180-200 parts of anhydrous tetrahydrofuran, 300-350 parts of chloromethane, 450-500 parts of anhydrous toluene, 20-25 parts of cyanopyrazine, 40-50 parts of alcohol, 2 parts of activated carbon and a plurality parts of chloromethane. Acetylpyrazine has the advantages that the synthesis method is simple, the raw materials are easy to obtain, energy consumption and material losses are low, the safety and the finished product content are high, and acetylpyrazine is suitable for large-scale production.

Description

[0001] Technical field: [0002] The invention specifically relates to a preparation method of acetylpyrazine, which belongs to the technical field of chemical industry. Acetyl [0003] Background technique: [0004] Acetyl pyrazine has the characteristic of popcorn-like aroma, melting point is 79-80°C, boiling point is 57-58°C (0.8kPa), there are many preparation methods for synthesizing acetylpyrazine, one is dehydration of pyrazinamide The corresponding nitrile is then reacted with the Grignard reagent methylmagnesium bromide and then hydrolyzed. Used in corn, sesame, peanut, beef and other food flavors, and can also be used in tobacco flavors. The final concentration in flavored foods is generally only (1-5) mg / kg. Another preparation method synthesizes methylmagnesium chloride from methyl chloride, condenses with cyanopyrazine, and then directly hydrolyzes and extracts the product to obtain the product, all of which use ether as a solvent. Because the Grignard reaction...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/12
CPCC07D241/12
Inventor 任伟刘雪静杨亮杨位祥
Owner SHANDONG JITIAN AROMA CHEM CO LTD
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