Preparation method of 2-methyl-5-aminophenol

Abstract

The invention relates to a preparation method of 2-methyl-5-aminophenol, which comprises the following steps: (1) carrying out nucleophilic substitution reaction on benzyl alcohol and 3-chloro-4-methylnitrobenzene in a solvent in the presence of a strong base to prepare an intermediate product, with the molar ratio of hydroxyl ions in the strong base to the benzyl alcohol to the 3-chloro-4-methylnitrobenzene being 1: (1.0-1.1): (0.5-1), and the reaction temperature being 10-20 DEG C; (2) hydrogenation reduction reaction: carrying out hydrogenation reduction on the intermediate product prepared in the step (1) to prepare a 2-methyl-5-aminophenol crude product, wherein the reaction temperature is 50-75 DEG C, and the hydrogen pressure is 0.7-1.0 Mpa; and (3) purification: decolorizing the crude product of the 2-methyl-5-aminophenol, and recrystallizing to obtain the high-purity 2-methyl-5-aminophenol. By adopting the method disclosed by the invention, the product quality is improved, the environmental pollution is reduced, the cost is reduced, the operation is simple, the reaction condition is mild, the product production is clean and environment-friendly, and the method is more suitable for mass production.

Description

technical field

[0001] The invention relates to the technical field of chemical material preparation, in particular to a preparation method of 2-methyl-5-aminophenol. Background technique

[0002] 2-Methyl-5-aminophenol is an important chemical raw material, which is widely used in many fields such as synthetic resins, pigments, dyes, medicines, pesticides, agricultural chemicals, photosensitive materials and explosives. The disinfection and sterilization function has also been widely used in shampoos, skin care products and other products in recent years.

[0003] In the 1980s, people began to study the synthesis method of 2-methyl-5 aminophenol. So far, the synthesis methods of 2-methyl-5 aminophenol include the following four kinds:

[0004] 1. Use 2-methyl-5-nitroaniline as the starting material, first form a salt with sulfuric acid, and then undergo a diazotization reaction. The diazonium salt is hydrolyzed to prepare 2-methyl-5-nitrophenol, 2-methyl Base-5-nitropheno...

Examples

Embodiment 1

[0039] (1) Nucleophilic substitution reaction. Weigh 22.00g (0.55mol) sodium hydroxide, 59.40g (0.55mol) benzyl alcohol (nucleophilic reagent), 200.00g toluene and add in the four-necked flask to carry out mixed reaction, heat up to reflux and separate out wherein water, and then the temperature of the reaction material was lowered to 10-20°C, and a toluene solution of 3-chloro-4-methylnitrobenzene (85.75g / 0.50mol) was added dropwise, and the reaction temperature was controlled at 10-20°C during the dropping process. During the dropwise addition, red solids were formed in the reaction material. After the dropwise addition, the temperature in the kettle was maintained at 10-20°C for 3.0 hours. The reaction material was sampled for HPLC (high performance liquid chromatography) control analysis. When the raw material in the reaction material was 3 When the content of -chloro-4methylnitrobenzene is less than 1.0%, the reaction is qualified, and then the reaction material is cooled...

Embodiment 2

[0043](1) Nucleophilic substitution reaction. Weigh 32.42g (0.55mol) 95% potassium hydroxide, 59.40g (0.55mol) benzyl alcohol (nucleophilic reagent), 200.00g toluene and add in the four-necked flask, after being warmed up to reflux, separate out wherein water, and then the temperature of the reaction material was lowered to 10-20°C, and a toluene solution of 3-chloro-4-methylnitrobenzene (85.75g / 0.50mol) was added dropwise, and the reaction temperature was controlled at 10-20°C during the dropping process. During the dropwise addition, red solids were formed in the reaction material. After the dropwise addition, the temperature in the kettle was maintained at 10-20°C for 3.0 hours, and samples were taken for HPLC (high performance liquid chromatography) control analysis. When the raw material 3-chloro When the content of -4 methylnitrobenzene < 1.0%, the reaction is qualified, then the reaction material is cooled to 0 ~ 5 ° C for 1.0 h of heat preservation and crystallization,...

Embodiment 3

[0047] (1) Nucleophilic substitution reaction. Weigh 22.00g (0.55mol) sodium hydroxide, 59.40g (0.55mol) benzyl alcohol (nucleophile), 200.00g toluene and add in the four-necked flask, heat up to reflux and separate the water therein through the water separator, Finally, the temperature of the reaction material was lowered to 10-20°C, and a toluene solution of 3-chloro-4-methylnitrobenzene (85.75g / 0.50mol) was added dropwise. During the addition process, a red solid was formed in the reaction material. After the dropwise addition, the temperature in the kettle was maintained at 10-20°C for 3.0 hours, and samples were taken for HPLC (high performance liquid chromatography) control analysis. When the raw material 3-chloro When the content of -4 methylnitrobenzene < 1.0%, the reaction is qualified, then the reaction material is cooled to 0 ~ 5 ° C for 1.0 h of heat preservation and crystallization, filtered after heat preservation and crystallization, and the filter cake is washe...

technical field

[0001] The invention relates to the technical field of chemical material preparation, in particular to a preparation method of 2-methyl-5-aminophenol. Background technique

[0002] 2-Methyl-5-aminophenol is an important chemical raw material, which is widely used in many fields such as synthetic resins, pigments, dyes, medicines, pesticides, agricultural chemicals, photosensitive materials and explosives. The disinfection and sterilization function has also been widely used in shampoos, skin care products and other products in recent years.

[0003] In the 1980s, people began to study the synthesis method of 2-methyl-5 aminophenol. So far, the synthesis methods of 2-methyl-5 aminophenol include the following four kinds:

[0004] 1. Use 2-methyl-5-nitroaniline as the starting material, first form a salt with sulfuric acid, and then undergo a diazotization reaction. The diazonium salt is hydrolyzed to prepare 2-methyl-5-nitrophenol, 2-methyl Base-5-nitropheno...

Examples

Embodiment 1

[0039] (1) Nucleophilic substitution reaction. Weigh 22.00g (0.55mol) sodium hydroxide, 59.40g (0.55mol) benzyl alcohol (nucleophilic reagent), 200.00g toluene and add in the four-necked flask to carry out mixed reaction, heat up to reflux and separate out wherein water, and then the temperature of the reaction material was lowered to 10-20°C, and a toluene solution of 3-chloro-4-methylnitrobenzene (85.75g / 0.50mol) was added dropwise, and the reaction temperature was controlled at 10-20°C during the dropping process. During the dropwise addition, red solids were formed in the reaction material. After the dropwise addition, the temperature in the kettle was maintained at 10-20°C for 3.0 hours. The reaction material was sampled for HPLC (high performance liquid chromatography) control analysis. When the raw material in the reaction material was 3 When the content of -chloro-4methylnitrobenzene is less than 1.0%, the reaction is qualified, and then the reaction material is cooled...

Embodiment 2

[0043](1) Nucleophilic substitution reaction. Weigh 32.42g (0.55mol) 95% potassium hydroxide, 59.40g (0.55mol) benzyl alcohol (nucleophilic reagent), 200.00g toluene and add in the four-necked flask, after being warmed up to reflux, separate out wherein water, and then the temperature of the reaction material was lowered to 10-20°C, and a toluene solution of 3-chloro-4-methylnitrobenzene (85.75g / 0.50mol) was added dropwise, and the reaction temperature was controlled at 10-20°C during the dropping process. During the dropwise addition, red solids were formed in the reaction material. After the dropwise addition, the temperature in the kettle was maintained at 10-20°C for 3.0 hours, and samples were taken for HPLC (high performance liquid chromatography) control analysis. When the raw material 3-chloro When the content of -4 methylnitrobenzene < 1.0%, the reaction is qualified, then the reaction material is cooled to 0 ~ 5 ° C for 1.0 h of heat preservation and crystallization,...

Embodiment 3

[0047] (1) Nucleophilic substitution reaction. Weigh 22.00g (0.55mol) sodium hydroxide, 59.40g (0.55mol) benzyl alcohol (nucleophile), 200.00g toluene and add in the four-necked flask, heat up to reflux and separate the water therein through the water separator, Finally, the temperature of the reaction material was lowered to 10-20°C, and a toluene solution of 3-chloro-4-methylnitrobenzene (85.75g / 0.50mol) was added dropwise. During the addition process, a red solid was formed in the reaction material. After the dropwise addition, the temperature in the kettle was maintained at 10-20°C for 3.0 hours, and samples were taken for HPLC (high performance liquid chromatography) control analysis. When the raw material 3-chloro When the content of -4 methylnitrobenzene < 1.0%, the reaction is qualified, then the reaction material is cooled to 0 ~ 5 ° C for 1.0 h of heat preservation and crystallization, filtered after heat preservation and crystallization, and the filter cake is washe...

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