Clean production method of nitrochlorobenzene

Abstract

The invention discloses a clean production method of nitrochlorobenzene. The production method concretely comprises the following steps: enabling chlorobenzene to react with nitric acid under the action of sulfuric acid to generate a nitrochlorobenzene mixture, separating the nitrochlorobenzene mixture from waste sulfuric acid, which is generated via nitration, by using a sedimentation method, neutralizing and washing an acidic nitrochlorobenzene mixture so as to enable the mixture to reach neutrality, drying a neutral nitrochlorobenzene mixture to remove the chlorobenzene, moisture and the like therein to obtain a crude nitrochlorobenzene mixture, then separating out two products, i.e., p-nitrchlorobenzene and o-nitrophenol, as well as meta-position oil rich in m-nitrochlorobenzene and high boiling point organic matter waste liquid by using a separation method in which crystallization, rectification and recrystallization are combined, in the clean production method of the nitrochlorobenzene, nitrating waste acid is subjected to vacuum concentration dehydration, after the sulfuric acid concentration is greater than 88%, the nitrating waste acid and nitric acid are prepared into mixed acid for cycle use, and the clean production method of the nitrochlorobenzene improves the economic benefit, optimizes the clean production method and process design of the nitrochlorobenzene, and meets the requirement of the clean production method and the process design on the nitrochlorobenzene.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a clean production method of nitrochlorobenzene. Background technique [0002] Nitrochlorobenzene is an intermediate of many fine chemical products such as medicine, pesticide and dye. The production of nitrochlorobenzene is based on chlorobenzene, and the mixed acid of nitric acid and sulfuric acid is used as the nitrating agent for nitration. The crude product obtained by nitration needs to be washed with alkali and water, and then separated and purified by a rectification tower to obtain p-nitrochlorobenzene. Chlorobenzene and o-nitrochlorobenzene. [0003] o-nitrochlorobenzene, p-nitrochlorobenzene and its derivative product p-nitroanisole are important intermediates for dyes, medicines, pesticides, and spices. The main production route is: nitration reaction of chlorobenzene at a certain temperature and pressure , to generate a nitrochlorobenzene mixture, inclu...

AI Technical Summary

Problems solved by technology

[0005] Under the current technical conditions, it is feasible to continue to separate and purify the components in this part of the mixture by rectification-crystallization, but due to the similar physical properties, it is very difficult to implement

In order to obtain m-nitrochlorobenzene finished products, the m-nitrochlorobenzene in the material taken from the top of the rectification tower must be greater than 80% before crystallization, otherwise the purity of the m-nitrochlorobenzene product is insufficient or the yield is extremely low due to mutual solubility, and the intermediate The boiling points of nitrochlorobenzene and p-nitrochlorobenzene are 237°C and 239°C respectively, and the difference between the boiling points is only 2°C. During rectification, a high reflux ratio and a small amount taken from the top of the tower are required to meet the process requirements. High energy consumption and long production cycle

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