CN101955467A - Preparation method of 2, 3, 5-trimethylpyrazine - Google Patents
Preparation method of 2, 3, 5-trimethylpyrazine Download PDFInfo
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- CN101955467A CN101955467A CN2010105155388A CN201010515538A CN101955467A CN 101955467 A CN101955467 A CN 101955467A CN 2010105155388 A CN2010105155388 A CN 2010105155388A CN 201010515538 A CN201010515538 A CN 201010515538A CN 101955467 A CN101955467 A CN 101955467A
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- trimethylpyrazine
- preparation
- temperature
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- butanone
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Abstract
The invention discloses a preparation method of 2, 3, 5-trimethylpyrazine. In the invention, low-cost chemical raw materials (3-hydroxy-2-butanone and 1, 2-propane diamine) are used for synthesizing the product of 2, 3, 5-trimethylpyrazine by controlling reaction conditions with high selectivity. The preparation method of 2, 3, 5-trimethylpyrazine is characterized by comprising the following steps of: reducing the temperature of a low-temperature bath to -5-0 DEG C, adding 150ml of water and 220g of 1,2 propane diamine, controlling the temperature in a bottle to be 0-15 DEG C, dropwise adding 250g of 3-hydroxy-2-butanone, and stirring to react for 0.5h. The product of 2, 3, 5-trimethylpyrazine can be synthesized with high selectivity by controlling the reaction conditions.
Description
Technical field
" 2.3.5-trimethylpyrazine " is mainly used in foodstuff additive, and it has the special aroma of roasted nuts, belongs to technical field of food additives.
Background technology
At present, " 2.3.5-trimethylpyrazine " preparation method mainly contains following three kinds: a. is by " 2.3-dimethyl diketone " and " 1.2-propylene diamine " condensation, dehydrogenation preparation; B song " 2.3-butylene oxide ring " and " 1.2-propylene diamine " addition, and then dehydration, dehydrogenation are synthetic; C. prepare through dehydration, dehydrogenation by " 2.3-butyleneglycol " and " 1.2-propylene diamine "." 2.3-dimethyl diketone ", " 2.3 butylene oxide ring ", " 2.3 butyleneglycol " price are all higher in above three kinds of methods, have limited a large amount of uses of the product of changing products.
Summary of the invention
The invention provides a kind of " 2.3.5-trimethylpyrazine " preparation method, it adopts industrial chemicals (" 3-hydroxyl-2-butanone " and " 1.2 propylene diamine ") cheaply, by the control reaction conditions, but synthetic " 2.3.5-trimethylpyrazine " product of highly selective.
The technical scheme that the present invention takes is: a kind of " 2.3.5-trimethylpyrazine " preparation method, it is characterized in that: the cryostat, temperature is reduced to-5～0 ℃, add entry 150ml, 1.2 propylene diamine, 220 grams, temperature is 0～15 ℃ in the control bottle, drip " 3-hydroxyl-2-butanone " 250 grams, stirring reaction 0.5 hour; By the control reaction conditions, but synthetic " 2.3.5-trimethylpyrazine " product of highly selective.
Beneficial effect of the present invention: this preparation has highly selective, high yield, product purity height, characteristics that cost is low.
Embodiment
Embodiment 1: the cryostat, temperature is reduced to-5～0 ℃, add entry 150ml, 1.2 propylene diamine, 220 grams, temperature is 0～15 ℃ in the control bottle, drips " 3-hydroxyl-2-butanone " 250 grams, stirring reaction 0.5 hour; Remove cryostat,, change heating jacket, reduce to room temperature and get reaction mother liquor after temperature is heated to backflow in the bottle; Filling Zinc oxide catalytic in the stainless steel fixed-bed reactor (Dg25*1000mm), at first with the hydrogen activation, then with reactor column temperature rise to 350 ℃, feed reaction mother liquor, 340～370 ℃ of control column temperatures, flow 250ml/h, logical Bi Jixu feeds water 100ml; Above-mentioned reaction solution is collected, and then with ether 100ml*3 extraction, merging ether and heating are taken off ether to 80 ℃ of end temperature and are obtained " 2.3.5-trimethylpyrazine " crude product 380 grams, and content 80% obtains the product of content more than 98% with the crude product rectification under vacuum, about 280 grams.
Claims (1)
1. the preparation method of a kind " 2.3.5-trimethylpyrazine ", it is characterized in that: the cryostat, temperature is reduced to-5～0 ℃, add entry 150ml, 1.2 propylene diamine, 220 grams, temperature is 0～15 ℃ in the control bottle, drip " 3-hydroxyl-2-butanone " 250 grams, stirring reaction 0.5 hour; By the control reaction conditions, but synthetic " 2.3.5-trimethylpyrazine " product of highly selective.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105155388A CN101955467A (en) | 2010-10-22 | 2010-10-22 | Preparation method of 2, 3, 5-trimethylpyrazine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105155388A CN101955467A (en) | 2010-10-22 | 2010-10-22 | Preparation method of 2, 3, 5-trimethylpyrazine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101955467A true CN101955467A (en) | 2011-01-26 |
Family
ID=43483086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105155388A Pending CN101955467A (en) | 2010-10-22 | 2010-10-22 | Preparation method of 2, 3, 5-trimethylpyrazine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101955467A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108484512A (en) * | 2018-05-23 | 2018-09-04 | 滕州市悟通香料有限责任公司 | A method of synthesis 2,3,5- trimethylpyrazines |
-
2010
- 2010-10-22 CN CN2010105155388A patent/CN101955467A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108484512A (en) * | 2018-05-23 | 2018-09-04 | 滕州市悟通香料有限责任公司 | A method of synthesis 2,3,5- trimethylpyrazines |
| CN108484512B (en) * | 2018-05-23 | 2020-05-05 | 滕州市悟通香料有限责任公司 | Method for synthesizing 2,3, 5-trimethylpyrazine |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20110126 |