Method for preparing melonal by utilizing decarboxylation of 2,3-epoxy-3,7-dimethyl-6-octenic acid

A technology of melon and epoxy group, which is applied in the preparation of heterocyclic compounds, organic chemistry, etc., can solve the problems of reducing the vacuum degree, unfavorable output of melon, etc., and achieves the effects of reducing requirements, shortening preparation time, and improving utilization rate.

Inactive Publication Date: 2017-06-20
ANHUI HYEA AROMAS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

And the carbon dioxide gas produced in the reaction process will reduce the vacuum degree in the reaction rectification process, is unfavorable for the output of melon aldehyde, and produces a large amount of high-boiling point impurities

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Take 300g of 97# industrial white oil and add it to the decarboxylation reactor, turn on the water circulation vacuum pump; heat the reactor temperature to 155°C under vacuum. Take the 85% melon aldehyde precursor α, β-epoxy acid 500g (2.31mol), pH=5, and use a peristaltic pump to drip into the above reaction system, the dripping time is controlled at 2h. The water in the melon aldehyde and melon precursor α, β-epoxy acid oil layer produced by the reaction is azeotropically cooled by the condenser and collected in the receiving tank. After the dripping is completed, the temperature is kept for 30 minutes. The oil layer in the receiving tank is obtained by standing and stratifying The melon aldehyde oil layer is 323 g, the content is 90%, and the selectivity of the melon aldehyde precursor α, β-epoxy acid decarboxylation is 90%.

Embodiment 2

[0028] Take 300g of 97# industrial white oil and add it to the decarboxylation reactor, turn on the water circulation vacuum pump; heat the reactor temperature to 165°C under vacuum. Take the 85% melon aldehyde precursor α, β epoxy acid 500g (2.31mol), pH=5, use a peristaltic pump to drip into the above reaction system, the dripping time is controlled at 2h. The water in the melon aldehyde and melon precursor α, β-epoxy acid oil layer produced by the reaction is azeotropically cooled by the condenser and collected in the receiving tank. After the dripping is completed, the temperature is kept for 30 minutes. The oil layer in the receiving tank is obtained by standing and stratifying The melon aldehyde oil layer is 340g, the content is 89%, and the melon aldehyde precursor α, β-epoxy acid decarboxylation selectivity is 93%.

Embodiment 3

[0030] Take 300g of 97# industrial white oil and add it to the decarboxylation reactor, turn on the water circulation vacuum pump; heat the reactor temperature to 165°C under vacuum. Take the 85% melon aldehyde precursor alpha, beta epoxy acid 500g (2.31mol), pH=2, use a peristaltic pump to drip into the above reaction system, the dripping time is controlled at 2h. The water in the melon aldehyde and melon precursor α, β-epoxy acid oil layer produced by the reaction is azeotropically cooled by the condenser and collected in the receiving tank. After the dripping is completed, the temperature is kept for 30 minutes. The oil layer in the receiving tank is obtained by standing and stratifying The melon aldehyde oil layer is 320 g, the content is 89%, and the melon aldehyde precursor α, β-epoxy acid decarboxylation selectivity is 87.9%.

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Abstract

The invention discloses a method for preparing melonal by utilizing decarboxylation of 2,3-epoxy-3,7-dimethyl-6-octenic acid and relates to the technical field of fine chemical engineering. The method comprises the following steps: adding industrial grade white oil into a reaction kettle, and raising the temperature of the reaction kettle to a decarboxylic reaction temperature under vacuum conditions; continuously dripping a melonal precursor alpha,beta-epoxy acid aqueous solution into the reaction kettle at the same dripping speed, maintaining the temperature and reacting after dripping completion, enabling the melonal produced in the reaction to immediately realize azeotrope with water, cooling through a condenser pipe, collecting cooling liquid into a receiving tank, standing the cooling liquid collected in the receiving tank, performing water diversion so as to obtain the product melonal, and immediately discharging carbon dioxide produced in the reaction from the top of the condenser pipe. According to the method disclosed by the invention, the decarboxylic reaction is rapidly carried out in a manner of dripping the raw materials into the white oil heated to the decarboxylic reaction temperature, the heating time of the raw materials is reduced, and side reactions are avoided. Moreover, By virtue of a manner of simultaneously performing decarboxylic reaction and azeotropic distillation of the product, the melonal produced in the reaction is immediately separated out of the reaction system.

Description

[0001] Technical field: [0002] The invention relates to the technical field of fine chemicals, in particular to a method for preparing melon aldehyde by decarboxylation of 2,3-epoxy-3,7-dimethyl-6-octenoic acid. [0003] Background technique: [0004] Melon aldehyde has a strong, fresh melon-like fruit aroma and is widely used in the formulation of edible flavors such as beverages and candies. Melon aldehyde is mainly produced by Darens reaction between methylheptenone and ethyl chloroacetate. Firstly, sodium ethoxide is used as a condensing agent to condense the two into epoxy ester, and then saponified and acidified to become the corresponding epoxy acid intermediate , And then heat decarboxylation and rearrangement under acidic conditions to synthesize melon aldehyde. [0005] Ni Weizhong reported in "Preparation of 2, 6-Dimethyl-5-heptenal by Reactive Distillation" that methylheptenone and methyl chloroacetate are used as raw materials to prepare melon aldehyde through condensat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/58C07C47/21
CPCC07C45/58C07C47/21
Inventor 汪洋张政何云飞钱门
Owner ANHUI HYEA AROMAS
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