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Acetoin synthesis method

A synthetic method and technology of acetoin, applied in the field of acetoin synthesis, can solve problems such as toxicity

Inactive Publication Date: 2017-09-22
HUAIYIN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The present invention aims at the toxicity and danger caused by the use of acetonitrile solvent in the preparation process of the catalyst required for the synthesis of acetoin, and provides an improved acetoin synthesis method to realize the safe and environment-friendly production of acetoin

Method used

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preparation example Construction

[0019] The invention provides a kind of synthetic method of acetoin, comprising the following steps:

[0020] Step 1, preparing the catalyst: after equimolar mixing of thiothiazole (I) and ethyl bromide, acetoin is used as a solvent, and the temperature is 150° C. to 160° C. in an oil bath for reflux reaction for 28 to 32 hours. After the reaction, Stir and cool down to room temperature, and recover the solvent by rotary evaporation. After standing still, suction filtration and washing, the precipitated white precipitate is recrystallized by acetoin and dried to obtain the catalyst 3-ethyl-4-methyl-5-hydroxyethyl Thiazolium bromide (II); the

[0021] Step 2, acetaldehyde condensation synthesis of acetoin: add catalyst 3-ethyl-4-methyl-5-hydroxyethylthiazole bromide (II) to the acetaldehyde solution, the molar ratio of acetaldehyde to catalyst is 500~ 600:1, and use sodium bicarbonate to adjust the pH value to 9-10, then heat it to 110-130°C in the pressure reactor, and stir t...

Embodiment 1

[0023] 1) To a three-necked flask equipped with a reflux device, sequentially add equimolar thiothiazole and ethyl bromide, and use acetoin as a solvent, reflux for 28 hours under heating in an oil bath at 150°C, and continue stirring until the reaction solution drops to room temperature , the solvent was recovered by rotary evaporation, the remaining reaction liquid was left to stand for 8 hours, suction filtered, washed with acetoin to obtain a white solid, and after acetoin was recrystallized, dried in a vacuum oven at 50°C to obtain 3-ethyl-4- Methyl-5-hydroxyethylthiazolium bromide.

[0024] 2) Add acetaldehyde and 3-ethyl 4-methyl-5-hydroxyethylthiazole bromide with a molar ratio of 500:1 into a 2L pressure reactor, and adjust the pH value of the reaction solution to 9 with sodium bicarbonate , start stirring and heat up to 110°C, the reaction starts automatically, the pressure of the reactor gradually rises to 1.5MPa, and drops to 0Mpa after 3 hours, indicating that the...

Embodiment 2

[0027] 1) To a three-necked flask equipped with a reflux device, add equimolar thiothiazole and ethyl bromide sequentially, and use acetoin as a solvent, reflux for 30 hours under heating in an oil bath at 155°C, and continue stirring until the reaction solution drops to room temperature , the solvent was recovered by rotary evaporation, the remaining reaction liquid was left to stand for 8 hours, suction filtered, washed with acetoin to obtain a white solid, and after acetoin was recrystallized, dried in a vacuum oven at 50°C to obtain 3-ethyl-4- Methyl-5-hydroxyethylthiazolium bromide.

[0028] 2) Add acetaldehyde and 3-ethyl 4-methyl-5-hydroxyethylthiazole bromide with a molar ratio of 550:1 into a 2L pressure reactor, and adjust the pH value of the reaction solution to 9.5 with sodium bicarbonate , start stirring and raise the temperature to 120°C, the reaction starts automatically, the pressure of the reactor gradually rises to 1.5MPa, and drops to 0Mpa after 3 hours, ind...

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Abstract

The invention provides an acetoin synthesis method. The method comprises 1, catalyst preparation: mixing 4-methyl-5-beta-hydroxyethyl thiazole (I) and bromoethane according to a mole ratio of 1: 1, carrying out heating reflux in an acetoin solvent in an oil bath for a reaction, then carrying out stirring cooling to the room temperature, carrying out rotary evaporation, recovering the solvent, standing the white precipitates, carrying out suction filtration and washing, carrying out acetoin recrystallization and carrying out drying to obtain a catalyst 3-ethyl-4-methyl-5-hydroxyethyl thiazole bromide (II) and 2, carrying out acetaldehyde condensation to obtain acetoin, adding the catalyst 3-ethyl-4-methyl-5-hydroxyethyl thiazole bromide (II) into an acetaldehyde solution, adjusting pH to 9-10, carrying out heating stirring for a condensation reaction in a pressure reactor until the pressure in the pressure reactor is 0 MPa, mixing the reaction solution, the recovered solvent and solutions collected in standing, suction filtration and washing processes, and carrying out reduced pressure distillation to obtain acetoin (III).

Description

technical field [0001] The invention relates to a synthesis method, in particular to an acetoin synthesis method. Background technique [0002] Acetoin, also known as methyl acetylmethanol, 3-hydroxy 2-butanone, and vinegar, has a pleasant creamy aroma and is widely used in the preparation of wine, cream, honey, and strawberry-type spices. In my country's food additive use standard GB2760-1986, it is clearly stipulated that it is an edible food spice. In addition, acetoin can also be used to modify antibiotic drugs such as penicillin and ampicillin to improve drug efficacy, and is a compound with a wide range of uses. [0003] There are many studies on the synthesis methods of acetoin, and the representative ones are 2,3-butanedione selective reduction method, 2,3-butanediol selective oxidation method and acetaldehyde catalytic coupling method. The first two methods are limited by the high cost of the process, are still in the stage of laboratory research, and are difficul...

Claims

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Application Information

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IPC IPC(8): C07C49/17C07C45/72B01J31/02
CPCC07C45/72B01J31/0285B01J2231/342C07C49/17
Inventor 何磊黄秋月云山郭探洪坤朱秀芳张加栋陈静王朝宇许莹
Owner HUAIYIN INSTITUTE OF TECHNOLOGY
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