Preparation method of 3-(N,N-dimethylamino)phenol

Abstract

The invention relates to a preparation method of 3-(N,N-dimethylamino)phenol, and belongs to the technical field of fine chemical industry. The method comprises the following steps: reacting dimethylamine aqueous solution and resorcinol to obtain crude 3-(N,N-dimethylamino)phenol, then adding industrial liquid alkali in the crude product, adding toluene to extract by-products, neutralizing the aqueous phase, washing to remove unreacted resorcinol, and performing vacuum distillation to obtain 3-(N,N-dimethylamino)phenol. The method is simple for operations and has high product purity; and the storage and transportation of the raw materials are easy and the industrialized safety production can be performed easily.

Description

technical field

[0001] The invention relates to a preparation method of 3-(N,N-dimethylamino)phenol, which belongs to the technical field of fine chemicals. Background technique

[0002] 3-(N,N-Dimethylamino)phenol is used to synthesize dyes and pharmaceutical intermediates. The traditional production process of this compound is to react m-aminophenol with dimethyl sulfate, and then undergo multi-step purification to obtain 3-(N , N-dimethylamino) phenol, the production process needs to use highly toxic dimethyl sulfate, which has high requirements for safe production and raw material transportation, which is not conducive to industrialized production. Contents of the invention

[0003] The object of the present invention is to provide a preparation method of 3-(N,N-dimethylamino)phenol, which has simple operation, high product purity, easy storage and transportation of raw materials, and easy industrialized safe production.

[0004] The preparation method of 3-(N, N-dime...

Examples

Embodiment 1

[0018] At room temperature, sequentially add 354g of resorcinol and 450g of dimethylamine aqueous solution with a mass percentage concentration of 36% into a 2L autoclave, heat up to 175°C, keep warm until the end of the reaction, and when the material cools down to 30°C after the reaction , transfer it to a 5L four-necked bottle, slowly add 1142g of industrial liquid caustic soda with a concentration of 30% by mass percentage under stirring, cool down to 20°C, extract impurities twice with 500ml of toluene, and adjust the pH of the water phase to 6~6 with industrial hydrochloric acid 7. Stand to separate the layers, discard the water layer, wash the oil layer twice with 500ml of hot water at a temperature of 80°C, then distill under reduced pressure to collect the main fraction as 3-(N,N-dimethylamino)phenol.

Embodiment 2

[0020] At room temperature, sequentially add 354g of resorcinol and 430g of dimethylamine aqueous solution with a mass percentage concentration of 40% into a 2L high-pressure reactor, raise the temperature to 180°C, and keep it warm until the reaction is complete. After the reaction, the material is cooled to 25°C , transfer it to a 5L four-necked bottle, slowly add 1100g of industrial liquid caustic soda with a mass percentage concentration of 35% under stirring, cool down to 15°C, extract impurities twice with 600ml toluene, and adjust the pH of the water phase with 20% dilute sulfuric acid 6-7, let stand to separate layers, discard the water layer, wash the oil layer twice with 550ml of hot water with a water temperature of 70°C, then distill under reduced pressure, and collect the main fraction as 3-(N,N-dimethylamino)phenol .

Embodiment 3

[0022] At room temperature, sequentially add 354g of resorcinol and 420g of dimethylamine aqueous solution with a concentration of 45% by mass into a 2L autoclave, heat up to 190°C, and keep warm until the reaction is over. After the reaction, the material cools down to 20°C , transfer it to a 5L four-necked bottle, slowly add 1120g of industrial liquid caustic soda with a mass percentage concentration of 36% under stirring, cool down to 30°C, extract impurities twice with 500ml of toluene, and adjust the pH of the water phase with 30% dilute sulfuric acid 6-7, let stand to separate, discard the water layer, wash the oil layer twice with 600ml of hot water at a temperature of 60°C, then distill under reduced pressure, and collect the main fraction as 3-(N,N-dimethylamino)phenol .

technical field

[0001] The invention relates to a preparation method of 3-(N,N-dimethylamino)phenol, which belongs to the technical field of fine chemicals. Background technique

[0002] 3-(N,N-Dimethylamino)phenol is used to synthesize dyes and pharmaceutical intermediates. The traditional production process of this compound is to react m-aminophenol with dimethyl sulfate, and then undergo multi-step purification to obtain 3-(N , N-dimethylamino) phenol, the production process needs to use highly toxic dimethyl sulfate, which has high requirements for safe production and raw material transportation, which is not conducive to industrialized production. Contents of the invention

[0003] The object of the present invention is to provide a preparation method of 3-(N,N-dimethylamino)phenol, which has simple operation, high product purity, easy storage and transportation of raw materials, and easy industrialized safe production.

[0004] The preparation method of 3-(N, N-dime...

Examples

Embodiment 1

[0018] At room temperature, sequentially add 354g of resorcinol and 450g of dimethylamine aqueous solution with a mass percentage concentration of 36% into a 2L autoclave, heat up to 175°C, keep warm until the end of the reaction, and when the material cools down to 30°C after the reaction , transfer it to a 5L four-necked bottle, slowly add 1142g of industrial liquid caustic soda with a concentration of 30% by mass percentage under stirring, cool down to 20°C, extract impurities twice with 500ml of toluene, and adjust the pH of the water phase to 6~6 with industrial hydrochloric acid 7. Stand to separate the layers, discard the water layer, wash the oil layer twice with 500ml of hot water at a temperature of 80°C, then distill under reduced pressure to collect the main fraction as 3-(N,N-dimethylamino)phenol.

Embodiment 2

[0020] At room temperature, sequentially add 354g of resorcinol and 430g of dimethylamine aqueous solution with a mass percentage concentration of 40% into a 2L high-pressure reactor, raise the temperature to 180°C, and keep it warm until the reaction is complete. After the reaction, the material is cooled to 25°C , transfer it to a 5L four-necked bottle, slowly add 1100g of industrial liquid caustic soda with a mass percentage concentration of 35% under stirring, cool down to 15°C, extract impurities twice with 600ml toluene, and adjust the pH of the water phase with 20% dilute sulfuric acid 6-7, let stand to separate layers, discard the water layer, wash the oil layer twice with 550ml of hot water with a water temperature of 70°C, then distill under reduced pressure, and collect the main fraction as 3-(N,N-dimethylamino)phenol .

Embodiment 3

[0022] At room temperature, sequentially add 354g of resorcinol and 420g of dimethylamine aqueous solution with a concentration of 45% by mass into a 2L autoclave, heat up to 190°C, and keep warm until the reaction is over. After the reaction, the material cools down to 20°C , transfer it to a 5L four-necked bottle, slowly add 1120g of industrial liquid caustic soda with a mass percentage concentration of 36% under stirring, cool down to 30°C, extract impurities twice with 500ml of toluene, and adjust the pH of the water phase with 30% dilute sulfuric acid 6-7, let stand to separate, discard the water layer, wash the oil layer twice with 600ml of hot water at a temperature of 60°C, then distill under reduced pressure, and collect the main fraction as 3-(N,N-dimethylamino)phenol .

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