Preparation of o-chlorophenol

O-chlorophenol performance

Colorless to yellowish brown liquid with unpleasant and irritating smell; Freezing point 9 ℃, boiling point 174.9 ℃, 56.4 ℃ / 1.33kpa, relative density (d420) 1.2634, refractive index (nd20) 1.5524, flash point 63 ℃; Soluble in ethanol, ether, chloroform, glycerol and benzene, insoluble in water; It melts with concentrated sodium hydroxide to form catechol, reacts with phosphorus pentachloride to form o-dichlorobenzene, and forms an adduct with aluminum trichloride.

O-chlorophenol principle

1) Diazotization

O-chloroaniline was diazotized with nitrous acid and hydrolyzed to o-chlorophenol.

2) Hypochlorous acid chlorination method

Sodium phenolate was chlorinated with hypochlorous acid and acidified to obtain two chlorophenols, which were separated to obtain the product.

3) Chlorine chlorination

Two chlorophenols were obtained by chlorination of phenol with chlorine gas, and o-chlorophenol was obtained by separation.

Chlorine chlorination is introduced here.

O-chlorophenol process

Melt 250kg phenol and add it into the enamel reactor with 1000kg benzene as solvent. Control the temperature at 25 ℃± 2 ℃ and inject chlorine gas. Conduct chromatographic tracking during chlorination. When the contents of o-chlorophenol and p-chlorophenol meet the requirements, stop feeding chlorine gas. And air was introduced into the kettle to blow off the hydrogen chloride gas. Steam is introduced into the kettle jacket for heating, and benzene is distilled out, which can be reused. When it is steamed to 125 ℃ (21.33kpa), it is cooled to 70 ℃, and the fraction at 75 ℃ / 2.67 ~ 3.33kpa is collected under reduced pressure to obtain about 170kg of o-chlorophenol. Then collect the corresponding fraction at 85 ~ 130 ℃ / 2.00kpa to obtain about 90kg of p-chlorophenol. During chlorination, the chlorination depth shall be strictly controlled to avoid the production of 2,4-dichlorophenol which is difficult to separate.

The sodium chlorate chlorination process is as follows:

An aqueous solution containing 135 kg of sodium hydroxide was added to the chlorination reactor, and then 300 kg of phenol was added, which was dissolved by stirring. Cool, control the material temperature below 20 ℃, slowly add sodium hypochlorite (containing 250kg of total sodium hypochlorite) solution dropwise, stand for 6-8h, and add concentrated hydrochloric acid to adjust the pH to 2. Separate it after washing with water. Then wash it three times with 5% sodium carbonate solution, wash it to pH 4, separate out the oil layer, and collect the 75 ℃ / 2.67 ~ 3.33kpa fraction by vacuum distillation to obtain about 250kg of o-chlorophenol. Then collect about 130kg of p-chlorophenol at 85 ~ 130 ℃ / 2.0kpa.

O-chlorophenol Safety measures

(1) The raw materials phenol, chlorine and benzene are toxic. The equipment must be sealed. The hydrogen chloride produced in production must be sprayed and absorbed with water. The workshop should be well ventilated. Operators should wear labor protection articles.

(2) This product is an organic drug with toxicity similar to that of pentachlorophenol, which is irritating to skin and mucosa.

(3) Jar, sealed and stored in a cool and dry place. Store and transport according to the provisions of toxic liquid chemicals.