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Synthesis method of ethyl maltol intermediate

A technology of ethyl maltol and a synthesis method, applied in the direction of organic chemistry, etc., can solve the problems of easy volatility, high toxicity to the operator's body, and many losses, so as to reduce production and discharge, improve atomic utilization, and reduce production costs. Effect

Inactive Publication Date: 2012-10-31
HUAIYIN TEACHERS COLLEGE +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0016] Wherein there are certain problems in the Grignard reaction step: (1) bromoethane is used when preparing the Grignard reagent, and its atom utilization rate is only 27%, and its price is also higher; (2) the synthesis of the Grignard reagent requires Anhydrous diethyl ether or tetrahydrofuran should be selected as the solvent. The boiling point of anhydrous diethyl ether is 35.4°C. The boiling point is too low, volatile, has a lot of loss, is explosive, and is very harmful. It is difficult to apply to industrialization. The cost of tetrahydrofuran is high and it is miscible with water. Many, not easy to recycle
[0017] In addition, there are literature reports that benzene and tetrahydrofuran are mixed in a certain proportion as a solvent for the Grignard reaction. The reaction is easy to control and the cost is low. However, benzene is a highly carcinogenic and toxic organic compound, which is very harmful to the operator's body.

Method used

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  • Synthesis method of ethyl maltol intermediate
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  • Synthesis method of ethyl maltol intermediate

Examples

Experimental program
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Embodiment 1

[0026] Example 1: Magnesium powder (0.60 g, 25 mmol), iodine (0.06 g, 0.24 mmol), bromoethane (0.27 g, 2.5 mmol) were added to a 100 mL three-necked flask, and 30 mL of 2- Methyltetrahydrofuran, heated until the yellow color of the system faded, and passed through ethyl chloride gas (1.76 g, 27.5 mmol), the temperature was maintained at 20 ° C, and the reaction was completed for 60 minutes. The Grignard reagent was prepared; Furfural (1.92 g, 20 mmol), remove the water bath after the dropwise addition, stir at room temperature for 4 hours, monitor the end of the reaction, and use saturated NH 4 Cl extraction was performed three times (10 mL*3), and the solvent was removed by rotary evaporation to obtain the crude furfuryl ethanol, which was distilled under reduced pressure to obtain 2.06 g furfuryl ethanol (62-63°C / 8 mmg, yield 81.7%). The product was characterized by H NMR spectrum, which was consistent with the literature value. 1 H NMR (400 MHz, CDCl 3 ):δ 6.27 (dd, J =...

Embodiment 2

[0027] Example 2: Magnesium powder (0.60 g, 25 mmol), iodine (0.12 g, 0.47 mmol), bromoethane (0.27 g, 2.5 mmol) were added to a 100 mL three-necked flask, and 30 mL of 2- Methyl tetrahydrofuran, heated until the yellow color of the system faded, and passed through ethyl chloride gas (1.76 g, 27.5 mmol), the temperature was maintained at 30 ° C, and the reaction was completed for 30 minutes. The Grignard reagent was prepared; Furfural (1.92 g, 20 mmol), remove the water bath after the dropwise addition, stir at room temperature for 4 hours, monitor the end of the reaction, and use saturated NH 4 Cl extraction was performed three times (10 mL*3), and the solvent was removed by rotary evaporation to obtain the crude furfuryl ethanol, which was distilled under reduced pressure to obtain 2.08 g furfuryl ethanol (62-63°C / 8 mmg, yield 82.5%).

Embodiment 3

[0028] Example 3: Magnesium powder (0.60 g, 25 mmol), iodine (0.24 g, 0.95 mmol), bromoethane (0.27 g, 2.5 mmol) were added to a 100 mL three-necked flask, and 30 mL of 2- Methyltetrahydrofuran, heated until the yellow color of the system faded, and chloroethane gas (1.76 g, 27.5 mmol), the temperature was maintained at 40 ° C, the reaction was 120 minutes, and the Grignard reagent was prepared; add dropwise to the Grignard reagent under ice bath Furfural (1.92 g, 20 mmol), remove the water bath after the dropwise addition, stir at room temperature for 4 hours, monitor the end of the reaction, and use saturated NH 4 Cl extraction was performed three times (10 mL*3), and the solvent was removed by rotary evaporation to obtain the crude furfuryl ethanol, which was distilled under reduced pressure to obtain 2.05 g furfuryl ethanol (62-63°C / 8 mmg, yield 81.3%).

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Abstract

The invention discloses a synthesis method of an ethyl maltol intermediate, which is characterized in that ethyl chloride is used instead of bromoethane, and the solvent for Grignard reaction is 2-methyltetrahydrofuran or a mixed solvent containing 2-methyltetrahydrofuran. The invention has the following advantages: (1) the ethyl chloride is cheaper than the bromoethane, and has higher atomic economical efficiency than bromoethane, thereby reducing the generation of three wastes and having small hazards on the environment; and (2) the 2-methyltetrahydrofuran has poor water solubility and proper boiling point, and thus, has the advantages of high use safety and high recovery rate, thereby lowering the production cost and facilitating the industrialized application.

Description

technical field [0001] The invention relates to a synthesis method, in particular to a synthesis method of an ethyl maltol intermediate. Background technique [0002] Maltol includes ethyl maltol, also known as maltol, also known as larchic acid, which has the sweet aroma of caramel and mild fruity aroma. It is a very important spice and flavor synergist, widely used in daily chemicals, beverages , medicine, tobacco, wine and other fine chemical fields. [0003] Now the production process of maltol mainly adopts the synthesis route from furfural as the starting material. The specific process is: using anhydrous ether or tetrahydrofuran as solvent, magnesium powder and halogenated alkyl react to synthesize Grignard reagent, and then furfural reacts with Grignard reagent. Then obtain the furfuryl alcohol intermediate by hydrolysis; under low temperature conditions, the crude furfuryl alcohol intermediate is dissolved in methanol aqueous solution and chlorinated with chlorine,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/42
Inventor 安礼涛刘兴超陈兆刚陈文昌崔大军林祥
Owner HUAIYIN TEACHERS COLLEGE
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