Method for synthesizing o-chloro-p-aminotoluene from o-chloro-p-nitrotoluene through catalytic hydrogenation

Abstract

The invention discloses a method for synthesizing o-chloro-p-aminotoluene from o-chloro-p-nitrotoluene through catalytic hydrogenation. The method comprises the following steps: enabling the o-chloro-p-nitrotoluene to be dissolved in a methyl alcohol solvent according to a mass ratio of 1 to 1, and adding a raney nickel catalyst; after dissolving, feeding hydrogen, wherein a molar weight proportion of the o-chloro-p-nitrotoluene to the hydrogen is 1 to (3.5 to 4), controlling a reaction temperature to be 90-95 DEG C, and controlling a reaction pressure to be 1.6-2.2 MPa; while an input amountof the o-chloro-p-nitrotoluene is 1 ton, reducing reaction time is about 5-6 hours; transferring reducing solution to a solvent distillation column, performing atmospheric distillation to obtain coarse o-chloro-p-aminotoluene; transferring the coarse o-chloro-p-aminotoluene to a rectifying tower, performing negative pressure distillation to obtain refined o-chloro-p-aminotoluene, wherein a purityof the o-chloro-p-aminotoluene measured by using a gas chromatographic method is greater than 98.00%. Multi-sulfur waste water and multi-sulfur waste residues are not generated in a production process, the method is energy-saving and environmentally friendly, an operating process of the technology is simple and controllable, and production cost is reduced.

Description

technical field [0001] The invention relates to the industrial catalysis field of petrochemical industry, in particular to a method for synthesizing o-chloro-p-aminotoluene by catalytic hydrogenation of o-chloro-p-nitrotoluene. technical background [0002] O-chloro-p-aminotoluene is referred to as 2B oil for short. 2B oil is mainly used as an intermediate in the organic synthesis industry, and can also be used to produce pigments, coatings and pesticides. [0003] At present, most domestic 2B oil production methods adopt the alkali sulfide reduction method. Specifically, sulfur and sodium sulfide are formulated into sodium polysulfide, and sodium polysulfide is used to reduce o-chloro-p-nitrotoluene to 2B oil crude product, 2B oil crude product After rinsing and vacuum distillation, it is refined into 2B oil products. The production process produces a large amount of alkaline wastewater and alkali sulfide residues. The reaction chemical formula of the reduction method is: ...

AI Technical Summary

Problems solved by technology

[0005] The production process of the alkali sulfide reduction method is complicated, and the product quality is affected by many factors

Alkali sulfide is a strong alkali, and the corrosion of equipment is more complicated and serious. In addition, the wastewater generated in the production process is large and difficult to treat, which will cause environmental pollution. Therefore, the production line must be equipped with wastewater treatment devices, resulting in increased production costs.