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Method for preparing 5-methyl-2-hepten-4-one

A technology of heptene and methyl, which is applied in the field of preparation of 5-methyl-2-hepten-4-one, can solve the problems of difficult industrial production, cumbersome operation, and large pollution, and achieve easy industrial production and simple operation , the effect of reducing pollution

Inactive Publication Date: 2011-04-27
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve the technical problems in the above-mentioned preparation method of 5-methyl-2-hepten-4-one, such as large pollution, cumbersome operation, long reaction time, low yield, and difficulty in industrialized production, the present invention provides a A method for preparing 5-methyl-2-hepten-4-one using acetoacetate as a raw material, the method has the advantages of low pollution, simple operation and high yield, and is suitable for industrial production

Method used

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  • Method for preparing 5-methyl-2-hepten-4-one

Examples

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Embodiment 1

[0036] (1), the preparation of ethyl 2-methylbutyroacetate

[0037] In a 2L four-neck flask equipped with mechanical stirring, dropping funnel and thermometer, add 77.8g (1.05mol) of calcium hydroxide and 500ml of dichloromethane. Under rapid stirring, 130 g (1.0 mol) of ethyl acetoacetate was slowly added dropwise, the temperature was controlled at 20-30°C, and the dropwise addition time was about 20 minutes. After the dropwise addition, continue to stir for 0.5 hours, then add 138.6g (1.15mol) of 2-methylbutyryl chloride dropwise to it, maintain the temperature at 30-35°C, drop the time for about 1.5 hours, and then continue at 40°C Stir for 2 hours;

[0038] Dissolve 56.2g (1.05mol) of ammonium chloride in 350ml of water, add it to the above reactant at 30°C, stir for half an hour, add an appropriate amount of ammonia water to adjust the pH value of the solution to 9, and then add it at 30-35 Continue to stir for 3 hours at ℃ to obtain a solution containing ethyl 2-methyl...

Embodiment 2

[0045] (1), the preparation of ethyl 2-methylbutyroacetate

[0046] In a 2L four-neck flask equipped with mechanical stirring, dropping funnel and thermometer, add 77.8g (1.05mol) of calcium hydroxide and 500ml of dichloromethane. Under rapid stirring, 130 g (1.0 mol) of ethyl acetoacetate was slowly added dropwise, the temperature was controlled at 20-30°C, and the dropwise addition time was about 20 minutes. After the dropwise addition, continue to stir for 0.5 hours, then add 132.5g (1.10mol) of 2-methylbutyryl chloride dropwise to it, maintain the temperature at 30-35°C, drop the time for about 1.5 hours, and then continue at 40°C Stir for 2 hours;

[0047] Dissolve 56.2g (1.05mol) of ammonium chloride in 350ml of water, add it to the above reactant at 30°C, stir for half an hour, add an appropriate amount of ammonia water to adjust the pH value of the solution to 9, and then add it at 30-35 Continue to stir for 3 hours at ℃ to obtain a solution containing ethyl 2-methyl...

Embodiment 3

[0054] (1), the preparation of ethyl 2-methylbutyroacetate

[0055] In a 2L four-neck flask equipped with mechanical stirring, dropping funnel and thermometer, add 77.8g (1.05mol) of calcium hydroxide and 500ml of dichloromethane. Under rapid stirring, 130 g (1.0 mol) of ethyl acetoacetate was slowly added dropwise, the temperature was controlled at 20-30°C, and the dropwise addition time was about 20 minutes. After the dropwise addition, continue to stir for 0.5 hours, then add 126.5g (1.05mol) of 2-methylbutyryl chloride dropwise to it, maintain the temperature at 30-35°C, drop the time for about 1.5 hours, and then continue at 40°C Stir for 2 hours;

[0056] Dissolve 56.2g (1.05mol) of ammonium chloride in 350ml of water, add it to the above reactant at 30°C, stir for half an hour, add an appropriate amount of ammonia water to adjust the pH value of the solution to 9, and then add it at 30-35 Continue to stir for 3 hours at ℃ to obtain a solution containing ethyl 2-methyl...

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Abstract

The invention discloses a method for preparing spice 5-methyl-2-hepten-4-one with nutty aroma. The method comprises the following steps of: reacting acetoacetate serving as a raw material with 2-methylbutyryl chloride to obtain an intermediate of 2-methylbutyryl acetate; and condensing the intermediate with acetaldehyde to prepare the product of 5-methyl-2-hepten-4-one. The used acetoacetate, 2-methylbutyryl chloride and acetaldehyde are commercial products, and the reaction raw materials are readily available, namely the raw materials are low in cost. In addition, the method avoids a Grignard reaction and stoichiometric oxidation, and is environmentally-friendly, easy to operate and suitable for industrialization.

Description

technical field [0001] The invention relates to a preparation method of 5-methyl-2-hepten-4-one. Background technique [0002] 5-Methyl-2-hepten-4-one, also known as Hazelnutone. It is a very valuable edible and daily spice. It has a nutty aroma in high concentration, and has a flavor-enhancing effect in low concentration. It can be widely used in food, beverages, oral products and feed additives. [0003] The preparation method of 5-methyl-2-hepten-4-one at present is as follows according to bibliographical reports: [0004] (1) US patent (US4563365) uses sec-butylmagnesium bromide and crotonaldehyde to obtain intermediate 5-methyl-2-hepten-4-ol through Grignard reaction, and then chemically oxidizes with sodium dichromate to obtain the product . However, the first step of this method will produce 1,4-added by-products, and the second step uses sodium dichromate stoichiometric oxidation, which causes large pollution and the total yield is only 14.7%. [0005] (2), Chine...

Claims

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Application Information

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IPC IPC(8): C07C49/203C07C45/74
Inventor 梁立冬赵延伟贾卫民王之建
Owner SHANGHAI INST OF TECH
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