Method for preparing p-methoxybenzaldehyde by p-methoxybenzoic acid

A technology of p-methoxybenzaldehyde and methoxybenzoic acid, which is applied in the field of daily chemical industry, can solve the problems of expensive reagents, etc., and achieve the effects of saving production costs, mild reaction conditions, and easy industrial production

Active Publication Date: 2014-08-13
SUQIAN COSMOS CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reagents used in this method are very expensive, or the catalytic hydrogenation reduction is carried out under high temperature and high pressure, which makes this method need to solve many problems in the process of industrialization. At present, almost no manufacturers have realized the industrial hydrogenation of p-methoxybenzoic acid p-Methoxybenzaldehyde

Method used

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  • Method for preparing p-methoxybenzaldehyde by p-methoxybenzoic acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Add 152kg of p-methoxybenzoic acid, 300kg of o-xylene, and 118.8Kg of o-phenylenediamine into the reaction kettle, heat up to reflux (reaction temperature is 135-145° C.), and continuously separate the water produced by the reaction.

[0050] After 4.5 hours of reaction, the reaction was completed, and the temperature was directly lowered to 10-15° C., and filtered with suction, and the filtrate was used for the next batch. HPLC analysis filter cake content 99.5%, yield 98.5%.

[0051] HPLC-MS analysis molecular weight is 224, through 1 H-NMR detection confirmed that it was p-2-(4-methoxyphenyl)benzimidazole.

Embodiment 2

[0053] Add 152kg of p-methoxybenzoic acid, 300kg of m-xylene, and 118.8Kg of o-phenylenediamine into the reaction kettle, heat up to reflux (reaction temperature is 136-144° C.), and continuously separate the water produced by the reaction.

[0054] After 6.5 hours of reaction, the reaction was completed, and the temperature was directly lowered to 10-15°C, and suction filtered, and the filtrate was used for the next batch. HPLC analysis filter cake content 99.2%, yield 96.5%.

[0055] HPLC-MS analysis molecular weight is 224, through 1 H-NMR detection confirmed that it was p-2-(4-methoxyphenyl)benzimidazole.

Embodiment 3

[0057] Add 152kg of p-methoxybenzoic acid, 300kg of p-xylene, and 118.8Kg of o-phenylenediamine into the reaction kettle, heat up to reflux (reaction temperature is 137-150° C.), and continuously separate the water produced by the reaction.

[0058] After 4.0 hours of reaction, the reaction was completed, and the temperature was directly lowered to 10-15° C., filtered with suction, and the filtrate was used for the next batch. HPLC analysis filter cake content 99.4%, yield 93.7%.

[0059] HPLC-MS analysis molecular weight is 224, through 1 H-NMR detection confirmed that it was p-2-(4-methoxyphenyl)benzimidazole.

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Abstract

The invention relates to a method for preparing p-methoxybenzaldehyde by p-methoxybenzoic acid, which comprises the following steps: adding p-methoxybenzoic acid, o-phenylenediamine and a solvent in a condensation reaction kettle, wherein a catalyst is not used in the step, performing backflow water distribution when no water is generated; cooling, filtering to obtain 2-(4-methoxyphenyl)benzimidazole; adding a catalyst, absolute methanol and 2-(4-methoxyphenyl)benzimidazole in a hydrogenation reaction vessel, setting reaction temperature and hydrogen pressure, performing a hydrogenation reaction when hydrogen is unabsorbed, cooling to room temperature; recovering methanol from a filtrate, adding a sulfuric acid aqueous solution, performing backflow for reaction, then cooling to the temperature of 60-65 DEG C, separating the liquid to obtain an oil layer and a water layer, washing the oil layer to neutrality, and rectifying to obtain the final product. The preparation method has the advantages of mild reaction condition, low cost, less three wastes and easy realization of industrial production.

Description

technical field [0001] The invention relates to a preparation method of an organic intermediate, in particular to a preparation method of p-methoxybenzaldehyde, and belongs to the technical field of daily chemical industry. Background technique [0002] p-Methoxybenzaldehyde, also known as anisaldehyde, is a colorless to pale yellow liquid at room temperature, with a hawthorn-like smell, and exists in fennel oil, cumin oil, dill oil, acacia flowers, and incense in nature Extracted from viburnum extract, separated and extracted by oxidation. p-Methoxybenzaldehyde is an important intermediate for the synthesis of some spices, medicines, pesticides, etc. The synthesis technique of p-methoxybenzaldehyde mainly contains the following kinds. [0003] Utilize the natural anethole oxidation method (CN102336639A; Fragrance, Flavor and Cosmetics, No. 4, 1990, pages 4-6; Chemistry and Industry of Forest Products, 2009, Volume 29, No. 4, pages 59-62). This method uses a large amount ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/575C07C45/00C07C45/42
CPCC07C45/562C07D235/18C07C47/575Y02P20/584
Inventor 刘启发王荣高鹋葛建军杨茂霞
Owner SUQIAN COSMOS CHEM
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