Method for preparing p-chloroaniline without adding organic solvent

Abstract

The invention discloses a method for preparing p-chloroaniline without adding an organic solvent. The method is characterized by comprising the following steps: adding p-nitrochlorobenzene, a catalyst and an assistant in a high pressure kettle, sealing the high pressure kettle, opening a hydrogen valve to introduce hydrogen into the high pressure kettle, and meanwhile, stirring, heating and boosting, setting the reaction speed at 700 rpm, controlling the reaction temperature within 110-120 DEG C, controlling the reaction pressure within 1.1-1.2 MPa, reacting until no hydrogen is absorbed, closing the hydrogen valve, cooling, opening the high pressure kettle, discharging, filtering, adding the product into a rectifying kettle for distilling, and distilling to obtain the p-chloroaniline. A sample is taken, and a gas chromatography analysis result shows that the purity of the p-chloroaniline is 99.85%. The method disclosed by the invention has the advantages of simple operation, short production period, small environmental pollution, favorable environmental protection and low energy consumption, and is capable of recycling resources, reducing equipment investment and lowering the cost, and suitable for industrial production.

Description

1. Technical field: [0001] The invention belongs to the field of catalytic hydrogenation production, in particular to a method for preparing p-chloroaniline without adding an organic solvent. 2. Background technology: [0002] p-Chloroaniline is an important fine chemical intermediate, which is widely used in the production of fine chemicals such as pesticides, dyes, medicines, spices and rubber additives. In the process of preparing p-chloroaniline by catalytic hydrogenation of p-nitrochlorobenzene, it is necessary to add a large amount of volatile organic solvents to dissolve the raw materials or products, so as to increase the contact between the reactants, hydrogen and the three phases of the catalyst probability, enhance the mass transfer and heat transfer effect, and speed up the reaction rate; however, the use of solvents will increase post-treatment processes such as product separation and solvent recovery, resulting in increased investment costs, reduced system capa...

AI Technical Summary

Problems solved by technology

In the process of preparing p-chloroaniline by catalytic hydrogenation of p-nitrochlorobenzene, it is necessary to add a large amount of volatile organic solvents to dissolve the raw materials or products, so as to increase the contact between the reactants, hydrogen and the three phases of the catalyst probability, enhance the mass transfer and heat transfer effect, and speed up the reaction rate; however, the use of solvents will increase post-treatment processes such as product separation and solvent recovery, resulting in increased investment costs, reduced system capacity, increased energy consumption, reduced safety factor, and labor costs. A series of problems such as environmental deterioration