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Production method of 2-methyl-3(5 or 6)-methylthio pyrazine

A technology of methylthiopyrazine and a production method, which is applied in the production field of 2-methyl-3-methylthiopyrazine, can solve the problems of increased operation difficulty, poor product aroma, low product purity, etc., and can reduce production The effect of cost, improving product quality and simplifying operation steps

Active Publication Date: 2020-04-07
山东吉田生物科技有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] 1) The chlorination reaction operation is carried out under normal pressure. A large amount of chlorine gas escapes during the reaction process, which not only wastes raw materials, but also causes environmental pollution. After the chlorination reaction is completed in addition, the chlorine in the reaction system is all hydrolyzed, neutralized and processing, which wastes raw materials and increases the difficulty of operation
[0009] 2) In the existing 2-methyl-3(5 or 6)-methylthiopyrazine production process, the design of the post-treatment process is unreasonable, the composition of the product is relatively complicated, the product purity is low, and the aroma of the product is poor

Method used

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  • Production method of 2-methyl-3(5 or 6)-methylthio pyrazine

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Effect test

Embodiment 1

[0027] Embodiment 1: the synthesis of 2-methyl-3 (5 or 6)-chloropyrazine

[0028] 100L enamel reaction kettle, equipped with material dripping pipe (connected with metering pump), equipped with chlorine gas inlet pipe (connected with chlorine gas automatic control system), automatic pressure control system, temperature detection chain control system. Add 96kg of solvent dichloroethane and 1kg of triethylamine into the reaction kettle and start stirring, then feed chlorine gas, set the pressure in the kettle to be automatically controlled at 0.02-0.03MPa for 20-30 minutes. Then start feeding with a metering pump at a speed of 5kg / h (by mixing 10kg of methylpyrazine and 10kg of dichloroethane for use), the reaction exotherm is obvious, and the reaction temperature is controlled at 45~60°C, and the temperature is higher than 60°C. The feeding system is automatically cut off at ℃ (if necessary, the water can also be manually controlled to cool down), and the feeding is completed i...

Embodiment 2

[0029] Embodiment 2: the synthesis of 2-methyl-3 (5 or 6)-methylthiopyrazine

[0030] 100L enamel reaction kettle is equipped with thermometer, dropping, reflux and distillation devices. Add 34kg of sodium methyl mercaptide to the reactor, preheat to 80°C first, then control the temperature at 80-95°C, add 12kg of 2-methyl-3(5 or 6)-chloropyrazine dropwise, and drop it in about 3 hours , followed by reflux reaction, and at the same time, regular sampling and analysis, the reaction can be stopped by controlling 2-methyl-3(5 or 6)-chloropyrazine<0.02%. Then pass water to lower the temperature to below 40°C, extract twice with 12L×2 methyl tert-butyl ether, discard the water phase, combine the organic phases and return them to the kettle. Add 35kg of concentrated hydrochloric acid and 40kg of water mixed solution dropwise in the kettle, stir and react for 30 minutes, let stand to separate layers, discard the upper organic phase (recover methyl tert-butyl ether in addition), and ...

Embodiment 3

[0031] Embodiment 3: the synthesis of 2-methyl-3 (5 or 6)-chloropyrazine

[0032] 100L enamel reaction kettle, equipped with material dripping pipe (connected with metering pump), equipped with chlorine gas inlet pipe (connected with chlorine gas automatic control system), automatic pressure control system, temperature detection chain control system. Add 100kg of solvent dichloroethane and 1.1kg of triethylamine into the reaction kettle and start stirring, then feed chlorine gas, set the pressure inside the kettle to be automatically controlled at 0.02-0.03MPa for 20-30 minutes. Then start feeding with a metering pump at a speed of 5kg / h (by mixing 10kg of methylpyrazine and 10kg of dichloroethane for use), the reaction exotherm is obvious, and the reaction temperature is controlled at 45~60°C, and the temperature is higher than 60°C. The feeding system is automatically cut off at ℃ (if necessary, the water can also be manually controlled to cool down), and the feeding is comp...

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Abstract

The invention discloses a production method of 2-methyl-3(5 or 6)-methylthio pyrazine. The method comprises the following steps: adding solvents dichloroethane and triethylamine into a reaction kettle, sealing the reaction kettle, introducing chlorine to control the pressure in the kettle at 0.02-0.03 MPa, pumping a methylpyrazine solution into the reaction kettle by using a metering pump, controlling the temperature at 45-60 DEG C, reacting, and transferring reaction liquid(containing the chlorine)in the kettle into a dichloroethane turnover tank through filter pressing for recycling after the reaction is finished; dissolving the residual 2-methyl-3(5 or 6)-chloropyrazine hydrochloride solid in the reaction kettle with water, adjusting the neutrality, and layering to obtain a 2-methyl-3(5or 6)-chloropyrazine crude product; and dropwise adding thechloropyrazine crude product is into sodium methyl mercaptide, performing reflux reaction , and after reaction liquid is extracted, adding an aid into an organic phase to generate a hydrochloride for separating the non-pyrazine product from the product to greatly improve the aroma quality of the obtained product. The product grade is improved, and the whole production process is safe and environmentally friendly.

Description

technical field [0001] The invention relates to a production method of 2-methyl-3(5 or 6)-methylthiopyrazine, which belongs to the technical field of food additive production. Background technique [0002] 2-Methyl-3(5 or 6)-methylthiopyrazine (Methylthiopyrazine) is a pyrazine fragrance. It has the aroma of popcorn, roasted almonds, hazelnuts, peanuts and cashews, and has the green smell of seafood such as crabs and shells. Type and baking flavor food flavor. 2-Methyl-3(5 or 6)-methylthiopyrazine can also be used as a pharmaceutical raw material or a pharmaceutical intermediate. [0003] 2-Methyl-3(5 or 6)-methylthiopyrazine, the molecular formula is C 6 h 8 N 2 S, the structural formula is as follows. At present, the mixture of the following three isomers is generally used as food flavor. [0004] [0005] At present, there are relatively few synthetic research reports on 2-methyl-3 (5 or 6)-methylthiopyrazine, and the current synthetic method is: reacting methyl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/18
CPCC07D241/18Y02A50/30
Inventor 杨位祥任伟杨亮刘书增张宏奎赵斌孙宜成
Owner 山东吉田生物科技有限公司
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