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A method and device for synthesizing 2,5-dimethylpyrazine

A technology of dimethylpyrazine and fixed bed, which is applied in organic chemistry and other fields, can solve the problems of high operating conditions, high production cost, and difficult separation, and achieve the effects of less energy consumption, short reaction cycle, and extended service life

Active Publication Date: 2017-12-29
WUTONG AROMA CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Most of the existing synthetic methods use halogenated ketones as raw materials, and the operating conditions are relatively high, and there are many by-products, which are difficult to separate, the production cost is relatively high, and the yield is relatively low.

Method used

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  • A method and device for synthesizing 2,5-dimethylpyrazine
  • A method and device for synthesizing 2,5-dimethylpyrazine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A mixture of propylene oxide, ammonia, and ammonium bicarbonate (molar ratio = 1:3:1.5) was added to a four-necked flask equipped with a stirrer, an air duct, a thermometer, and a reflux condenser. The speed of the mixer is 800r / min, the stirring time is 0.5h, and the intermediate product 1-amino-2-propanol will be obtained by concentration and deamination. Under the action of Cu-Zn catalyst I, the reaction is carried out in a fixed bed at 250°C to form The product 2,5-dimethylpyrazine has a yield of 70%.

[0037] A device for synthesizing 2,5-dimethylpyrazine, comprising a fixed bed, wherein a plurality of vertical inner tubes are arranged in the fixed bed body, and a plurality of groups of baffles are arranged at equal intervals along the direction of the inner tubes , the baffles are alternately located on both sides of the bed.

[0038] The fixed bed includes bed body 1, inner pipe 2, insulation layer 3, inlet and outlet ports 4 and 5, gas distributor 6, molten sal...

Embodiment 2

[0047] A mixture of propylene oxide, ammonia, and ammonium bicarbonate (molar ratio = 1:3:2) was added to a four-necked flask equipped with a stirrer, an air duct, a thermometer, and a reflux condenser. The speed of the mixer is 1000r / min, the stirring time is 1h, and the intermediate product 1-amino-2-propanol will be obtained by concentration and deamination, which will be reacted in a fixed bed at 270°C under the action of Cu-Zn catalyst I to produce product 2, The yield of 5-dimethylpyrazine was 84%.

Embodiment 3

[0049] A mixture of propylene oxide, ammonia, and ammonium bicarbonate (molar ratio = 1:4:1.5) was added to a four-necked flask equipped with a stirrer, an air duct, a thermometer, and a reflux condenser. The speed of the mixer is 1500r / min, the stirring time is 1.5h, and the intermediate product 1-amino-2-propanol will be obtained by concentration and deamination, which will react in a fixed bed at 300°C under the action of Cu-Zn catalyst II to produce product 2 , The yield of 5-dimethylpyrazine was 80%.

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Abstract

The invention discloses a method and a device for synthesising 2,5-dimethylpyrazine, and belongs to the field of organic synthesis. The method comprises the step of synthesizing 2,5-dimethylpyrazine through a matched fixed-bed device under the action of a copper-zinc catalyst by mainly using epoxypropane, ammonia and ammonium bicarbonate as raw materials. The method and the device disclosed by the invention have the advantages that a fixed-bed reactor is simple to operate, the yield is high, the wastewater quantity is low, environmental protection and control are quite beneficial, and the yield achieves more than 92%.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a method and a device for synthesizing 2,5-dimethylpyrazine. Background technique [0002] At present, the present invention relates to a method for preparing 2,5-dimethylpyrazine by using propylene oxide as raw material through ammonolysis and condensation. [0003] 2,5-Dimethylpyrazine, as a spice, was first discovered from cocoa in 1964. It exists in fried potatoes, and adding only 1-2PPM to food can obviously enhance the flavor of potatoes. Pyrazine compounds are used in more than 50 kinds of coffee, peanuts, barley, popcorn, potato products, soybean products, bread, tomato, pea, green bell pepper, sesame oil, dairy products, roasted hazelnuts, chicken soup, roast beef, boiled pork, etc. Although the content in natural foods is very small, they are all important factors that cause the characteristic aroma of these foods. Since the 1960s, research on the synthesis and appli...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D241/12
CPCC07D241/12
Inventor 陈祥臧传近毛浙徽管庆栋李新卫洁宋成斌李磊磊自妍妍潘延安
Owner WUTONG AROMA CHEM CO LTD