Purification process for o-phenylenediamine

Abstract

The invention discloses a purification process for o-phenylenediamine. An o-phenylenediamine crude product is used as a raw material and an ammonolysis and reduction process of o-chloronitrobenzene is employed by the synthesis of o-phenylenediamine. The purification process comprises the steps of transporting a crude product of o-phenylenediamine to a rectification tower kettle to carry out distillation and purification. During the whole rectification process, a vacuum degree is controlled at 6-10 mmHg; and a temperature of the tower kettle is controlled at about 145 + / -3 DEG C. Finally, a proper amount of a protective agent is added in materials of a product; and the materials are flaked under the vacuum or nitrogen protection to obtain a white o-phenylenediamine finished product. The purification process is advantageous in that process is simple; operation is stable and reliable; energy consumption is low; product quality is stable; and product yield is increased.

Description

technical field [0001] The invention relates to a purification process of o-phenylenediamine and belongs to the field of fine chemical preparation. Background technique [0002] O-phenylenediamine is an important organic chemical, often used as an intermediate for dyes, pesticides, auxiliaries, photosensitive materials, etc., for the manufacture of polyamide, polyurethane, carbendazim and thiophanate, vat red GG, leveling agent, Antiaging agent MB is also used in the preparation of developers, surfactants, etc. At present, with the development of technology, the demand for high-quality o-phenylenediamine in the international and domestic markets is increasing year by year. [0003] In the production process of benzotriazole with o-phenylenediamine as raw material, conventional crude o-phenylenediamine is usually used for production, and the generated benzotriazole needs to be pickled, washed with water, rectified, decolorized and recrystallized, etc. More process steps can...

AI Technical Summary

Problems solved by technology

[0003] In the production process of benzotriazole with o-phenylenediamine as raw material, conventional crude o-phenylenediamine is usually used for production, and the generated benzotriazole needs to be pickled, washed with water, rectified, decolorized and recrystallized, etc. More process steps can meet the requirements, otherwise there will be more impurities, which will make the content and color number difficult to meet the high-quality requirements. However, the quality requirements for benzotriazole in the market are getting higher and higher, so it is necessary to purify o-phenylenediamine. Process optimization to prepare high-quality benzotriazole

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