Method for producing o-dichlorobenzene by taking o-nitrochlorobenzene as raw material through one-pot method

Abstract

The invention relates to a method for producing o-dichlorobenzene by taking o-nitrochlorobenzene as a raw material through a one-pot method. The method is based on a continuous reactor, the continuous reactor is a reaction device formed by communicating a reaction kettle with a catalyst packed tower, an opening of the reaction kettle is directly connected with an inlet in the bottom of a tower body, the reaction kettle is provided with a feeding port and a ventilation port, a gas leading-out port is formed in the top of the catalyst packed tower, o-nitrochlorobenzene and continuously introduced chlorine are used as raw materials, a compound catalyst of peroxide and azo is used as a catalyst, a nitro-removal chlorination reaction is performed in a continuous reactor under the conditions of 225-255 DEG C and 0.11-0.15 Mpa to generate o-dichlorobenzene and tail gas nitroacyl chloride, the o-dichlorobenzene and the tail gas nitroacyl chloride are led out from the leading-out port in the top of the tower, and liquid o-dichlorobenzene is obtained by means of condensation, wherein the retention time of the o-dichlorobenzene and the tail gas nitryl chloride in the catalyst packed tower is 5-20 minutes. According to the method, o-dichlorobenzene is synthesized at high temperature in a short time, the energy consumption is remarkably reduced, byproducts are few, no isomeride exists, and the conversion rate is high and can reach 95% or above.

Description

technical field [0001] The invention relates to a production method of o-dichlorobenzene, in particular to a method for producing o-dichlorobenzene in one pot using o-nitrochlorobenzene as a raw material. Background technique [0002] O-dichlorobenzene is a colorless liquid with aromatic odor, melting point -17°C, insoluble in water, soluble in ethanol and ether, easily soluble in organic solvent benzene. O-dichlorobenzene can be used as an intermediate of broad-spectrum antifungal drug miconazole. The traditional synthesis methods include: 1) diazotization reaction of phenylenediamine with sulfuric acid and sodium nitrite to make diazonium salt, and then chlorination 2) O-chloroaniline is diazotized and chlorinated, and the synthesis rate of o-chloroaniline diazotization method is low and the production capacity is not high; 3) Ortho-dinitrobenzene is directly catalyzed by chlorination; 4) Benzene chlorination, the process control conditions of benzene chlorination are dif...

AI Technical Summary

Problems solved by technology

O-dichlorobenzene can be used as an intermediate of broad-spectrum antifungal drug miconazole. The traditional synthesis methods include: 1) diazotization reaction of phenylenediamine with sulfuric acid and sodium nitrite to make diazonium salt, and then chlorination 2) O-chloroaniline is diazotized and chlorinated, and the synthesis rate of o-chloroaniline diazotization method is low and the production capacity is not high; 3) Ortho-dinitrobenzene is directly catalyzed by chlorination; 4) Benzene chlorination method, the process control conditions of benzene chlorination method are difficult, and the separation efficiency is not high

Among them, the synthesis process of phenylenediamine diazotization method is complicated and has been eliminated.

O-dinitrobenzene, an explosive substance, exists in the chlorination method of o-dinitrobenzene, and there are great safety hazards in the synthesis process

[0003] The publication date is March 20, 2013. The Chinese invention patent with the publication number CN102976886A discloses a synthesis method of o-dichlorobenzene, using iron rings and fluorspar as catalysts. Compared with traditional synthesis methods, the consumption of raw materials is reduced. , the total production capacity (including the sum of the production capacity of p-dichlorobenzene, chlorinated benzene and o-dichlorobenzene) has increased, but the amount of catalyst used is relatively large, the production capacity of o-dichlorobenzene has not increased significantly, and there are many by-products. The process cannot be carried out continuously, the production efficiency is low, and the reaction residue cannot be effectively utilized.