Continuous ammoniation method of aniline organic intermediates

Abstract

The invention discloses a continuous ammoniation method of aniline organic intermediates. The continuous ammoniation method concretely comprises the following steps of feeding o-nitrochlorobenzene and concentrated ammonia liquid into a six-stage serially connected high-pressure autoclave in a continuous feeding and continuous discharging mode; performing reaction for 10 to 15 hours at the inside pressure of 5.3MPa and the reaction temperature being 170 DEG C; obtaining ortho-nitroaniline; then, transferring the reaction liquid into a secondary reaction kettle; adding caustic alkali for regulating the pH value to be 12 to 13; then, performing reaction for 10 to 30min; obtaining high-purity ortho-nitroaniline and byproducts of ammonium chloride. The continuous ammoniation method has advantages that useful substances can be effectively recovered from intermediates of ortho-nitroaniline produced from carbendazim after the primary reaction is completed; the content of the ortho-nitroaniline after the hydrogenation is 98 percent or higher; the synthesis cost is reduced; the economic benefits are improved; the ammoniation yield is improved; the continuous ammoniation method and process design of the aniline organic intermediates are optimized; the continuous ammoniation method and process design requirements of the aniline organic intermediates are met.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a method for continuous ammoniation of aniline organic intermediates. Background technique [0002] O-phenylenediamine is a white crystalline solid, which can be obtained by reduction of o-nitroaniline. It is mainly used in the production of benzimidazole fungicides, such as carbendazim and thiophanate-methyl. Suction-type carbendazim can prevent and control bacterial diseases of various crops, forest trees, fruits and vegetables, and preserve and store fruits and vegetables. In addition, o-phenylenediamine can also be used to prepare developer and surfactant. [0003] At present, there are mainly three methods for the industrial production of o-phenylenediamine in China: iron powder reduction, alkali sulfide reduction, and catalytic hydrogenation reduction. Although the production process of the first two routes is simple, the product yield is low and the cost is re...

AI Technical Summary

Problems solved by technology

However, in the existing catalytic hydrogenation process, no matter whether nickel is used as a catalyst or palladium / carbon is used as a catalyst, water or alcohols need to be added as a solvent. However, the use of solvents increases post-processing procedures such as product separation and solvent recovery. As a result, equipment investment and energy consumption increase, especially when alcohols with low boiling point and volatile are used as solvents, the safety and cleanliness of production are greatly reduced

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