Process and system for continuous preparation of phenylenediamine

Abstract

The invention discloses a process and a system for continuous preparation of phenylenediamine. With the process provided by the invention, benzene is used as a raw material; a solid acid catalyst is adopted; meanwhile, mixed acid is added; two-stage continuous nitration is performed; obtained mixed dinitrobenzene is directly subjected to two-stage continuous hydrogenation reduction without being separated; thus, the phenylenediamine is obtained. According to a scheme of the invention, a large amount of nitrobenzene and dinitrobenzene is not needed to be stored in the process; meanwhile, by adoption of a continuous pipeline reaction, a material is not accumulated, so possibility of sudden explosion is fundamentally eliminated; and the process is an intrinsically-safe preparation process forthe phenylenediamine.

Description

technical field

[0001] The invention relates to a method for synthesizing aniline compounds by catalytic hydrogenation, in particular to a continuous preparation process and system of phenylenediamine. Background technique

[0002] Nitrobenzene compounds are important fine chemical intermediates and can be widely used in dyes, medicines, pesticides and explosives. At present, the industry still adopts the traditional process of nitration under certain reaction conditions with benzene and nitric acid as raw materials and sulfuric acid as a catalyst. The disadvantage of this process is that a large amount of waste acid and waste water will be produced and need to be treated; in addition, for every 1 mole of nitrification reaction, the heat released is more than 100kJ, and the specific heat capacity of sulfuric acid is very small, and the temperature raised by heating sulfuric acid with the same heat is often It is three times higher than the temperature raised by heating wate...

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