A method for preparing o-fluoroaniline by hydrogenation of o-fluoronitrobenzene

Abstract

The invention discloses a method for preparing o-fluoroaniline by hydrogenating o-fluoronitrobenzene. The method comprises the following steps: 1, filling a fixed bed reactor with a catalyst, introducing air and heating; 2, uniformly mixing o-fluoronitrobenzene steam and preheated hydrogen to obtain mixed gas, introducing the mixed gas into the fixed bed reactor, and performing a catalytic hydrogenation reaction in the presence of the catalyst; and 3, delivering the material subjected to the catalytic hydrogenation reaction into a condenser, condensing the material to convert the o-fluoronitrobenzene steam in the material into a liquid state, and separating the liquid-state o-fluoronitrobenzene in an oil-water separator to obtain oil-state o-fluoroaniline. The o-fluoronitrobenzene is catalytically hydrogenated by adopting the method, the treatment amount is large, the o-fluoronitrobenzene is completely converted, the molar conversion rate of the o-fluoronitrobenzene is 100 percent, and the molar percentage of a defluorinated product is less than 0.1 percent; and the product separating and purifying operation is simple at low energy consumption, and no toxic or harmful ions are doped in the product.

Description

technical field [0001] The invention belongs to the technical field of catalytic hydrogenation, and in particular relates to a method for preparing o-fluoroaniline by hydrogenating o-fluoronitrobenzene. Background technique [0002] O-fluoroaniline is an important intermediate in the synthesis of fluorine-containing medicines and dyes. O-fluoroaniline can be used to synthesize thermosensitive dye FH-102, which is a kind of thermosensitive dye with wide application and excellent performance in black. The dye can be used in the production of computer terminal output printing paper, electrocardiogram recording paper, telephone fax paper and transparent heat-sensitive film for oil fields. At present, in China, o-fluoroaniline is mainly produced by reducing o-fluoroaniline with iron powder. This process will produce a large amount of iron sludge (every 1 ton of o-fluoroaniline will produce 2.2t~2.4t of iron sludge), and at the same time A large amount of amine-containing wastew...

AI Technical Summary

Problems solved by technology

This method requires less initial investment and is easy to implement, but it requires a lot of manpower, has poor safety, and produces a lot of waste liquid and waste residue. It has not yet been industrialized.

At present, there are few literature reports on the method and catalyst for the preparation of o-fluoroaniline by continuous fixed-bed catalytic hydrogenation. This process is safe, environmentally friendly, high in production efficiency, and requires less personnel. It is beneficial to large-scale industrial production in the long run.