Mother liquor ammonia gas recovery process after aminolysis of aniline organic intermediate

Abstract

The invention discloses a mother liquor ammonia gas recovery process after aminolysis of an aniline organic intermediate. The process specifically comprises the following steps: discharging ortho-nitroaniline-contained mixed solution obtained after an ammonolysis reaction of nitryl chlorobenzene and stronger ammonia water in a six-class series autoclave to flow through a flash tower, so as to recycle excess ammonia gas; transferring a liquid phase into a deamination tower, heating to further recycle ammonia gas and entering into a water scrubbing tower for water scrubbing, so as to remove ammonium chloride; transferring water scrubbing liquor into an alkalization kettle; dropping a high-concentration caustic alkali reagent into the water scrubbing liquor to further flash off residual ammonia gas; absorbing the recycled ammonia gas with an ammonia absorption tower under pressure. According to the process, the solution obtained after the ammonolysis reaction of nitryl chlorobenzene flows through a flash still, a deamination kettle and an alkalization kettle, so as to extract the ammonia gas therein, so that useful substances are effectively recycled, the synthesis cost is saved, the economic benefits are increased, the design for the mother liquor ammonia gas recovery process after aminolysis of the aniline organic intermediate is optimized, and the design requirements of the mother liquor ammonia gas recovery process after aminolysis are met.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a mother liquid ammonia gas recovery process after ammonolysis 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 yiel...

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

[0005] The mother liquor after preparing o-phenylenediamine by various methods contains a large amount of ammonium chloride by-products and unrecovered ammonia gas. Ammonium chloride can be used as a recycled product with great economic value, and ammonia gas can also be recycled. As far as the ammonification of o-nitroaniline, the waste discharge will seriously pollute the environment and land. The recovery of ammonium chloride from o-phenylenediamine will be a major research focus. How to design a more effective and environmentally friendly The recovery process of mother liquid ammonia gas after ammonolysis of aniline organic intermediates will be a problem that people in the industry need to face up to and solve

Images