Method for preparing vanillin and analogue thereof

A technology of analogs and vanillin, which is applied in the field of preparation of vanillin and its analogs, can solve the problems of expensive raw materials and achieve the effects of increased selectivity, high yield, and high oxidation selectivity

Inactive Publication Date: 2010-07-14
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the defects of expensive raw materials existing in the preparation process of existing monobromoaldehyde and the preparation of vanillin and ethyl vanillin by carrying out methoxylation and ethoxylation reactions of bromoaromatic intermediate...

Method used

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  • Method for preparing vanillin and analogue thereof
  • Method for preparing vanillin and analogue thereof
  • Method for preparing vanillin and analogue thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Synthetic monobromoaldehyde method A

[0025]

[0026] Add 37.4g (0.20mol) of monobromophenol, 24.0g (0.60mol) of NaOH, 150mL of methanol and 0.96g (0.004mol) of tricobalt tetroxide in the autoclave; Feed oxygen to maintain the pressure to react at 0.6Mpa, and stop the reaction after continuing the oxidation reaction for 6 hours.

[0027] After the reaction was complete, the reactant was transferred to a flask. Recover methanol by distillation. Add 240mL of water, heat to 95°C to completely dissolve monobromoaldehyde phenol sodium salt, remove the catalyst by hot filtration; filter the mother liquor to cool to room temperature, acidify with concentrated hydrochloric acid to pH = 5, and precipitate a large amount of yellow solid; freeze to 0°C to promote its complete Crystallize, filter, wash with water until neutral, and dry in vacuo to obtain 36.2 g of monobromaldehyde yellow powder solid, yield 90.0%.

[0028] Spectral data:

[0029] ESI-MS(m / z): 201(M+1), ...

Embodiment 2

[0039] (1) Synthetic monobromoaldehyde method B

[0040]

[0041] Add 37.4g (0.20mol) of monobromophenol, 24.0g (0.60mol) of NaOH, 150mL methanol and 0.95g (0.004mol) of cobalt chloride hexahydrate in the autoclave; heat after sealing the autoclave, stirring , feed oxygen at 100°C to maintain the pressure at 0.6Mpa, and continue the oxidation reaction for 6 hours before stopping the reaction.

[0042] After the reaction is over, transfer the reactant to a flask, distill and recover methanol, add 240mL of water, heat to 95°C to dissolve the monobromaldehyde phenol sodium salt, heat filter to remove the catalyst; filter the mother liquor to cool to room temperature, acidify to pH with concentrated hydrochloric acid = 5, a large amount of yellow solid precipitated; freeze to 0°C to promote its complete crystallization, filter, wash with water until neutral, and dry in vacuo to obtain 24.5 g of monobromaldehyde yellow powder solid, yield 80.6%.

[0043] Spectral data:

[0044...

Embodiment 3

[0054] Co(NO 3 ) 2 Instead of Co in Example 1 (one) 3 o 4 , other processes are with embodiment 1 (one).

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Abstract

The invention relates to a method for preparing vanillin and analogue thereof, which comprises the following steps: dissolving 4-methyl-2-bromophenol in methanol solution of alkali metal hydroxides, adding a cobalt catalyst into the mixture, putting reaction solution in a high-pressure reaction kettle, charging pressure oxygen into the reaction kettle under the heating condition to efficiently complete the oxidizing reaction, and preparing an intermediate 4-hydroxyl-3-bromo benzaldehydes by carrying out simple separation and neutralization; and using a cuprous salt-carbon monoxide or cuprous salt-methyl formate composite catalyst system to carry out catalysis on the 4-hydroxyl-3-bromo benzaldehydes in excessive alkoxy alkali metal compound-corresponding alkyl alcohol solution to make the alkoxylation substitution reaction occur efficiently under the heating condition in the reaction kettle to generate the vanillin and the analogue thereof. The invention has the advantages of high product yield, good purity, directly recyclable alcohol solvent, low environment pollution, low production cost and the like.

Description

【Technical field】 [0001] The invention relates to the technical field of vanillin, in particular to a method for preparing vanillin and its analogues. 【Background technique】 [0002] Vanillin is the largest synthetic fragrance in the world. It is not only used in the fragrance and flavor industry, but also an important organic synthesis intermediate, widely used in food, cosmetics, tobacco, pharmaceuticals and other industries. Ethyl vanillin has a stronger fragrance, refreshing and elegant fragrance. It has the advantages of less dosage, sufficient fragrance and no discoloration in fragrance blending. The fragrance is 3 to 4 times stronger than vanillin. It is widely used in the preparation of various Essence, used as a fixative and flavoring agent. Among the production routes currently used at home and abroad, all tend to use guaiacol and ethyl guaiacol-glyoxylic acid route to produce vanillin and ethyl vanillin. However, this route has disadvantages such as many synthes...

Claims

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Application Information

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IPC IPC(8): C07C47/575C07C47/58C07C45/36C07C45/64
Inventor 冀亚飞万欢臧佳良陈一芬金文虎王毅
Owner EAST CHINA UNIV OF SCI & TECH
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