Preparation method of 1,2-dichloro-4-nitrobenzene

Abstract

The invention discloses a preparation method of 1,2-dichloro-4-nitrobenzene. The preparation method comprises the following steps: adding p-nitrochlorobenzene into a sulfuric acid solution with a massfraction of 65%, carrying out stirring for dissolving of the p-nitrochlorobenzene, conducting heating to 55 DEG C, then adding potassium chlorate, carrying out a stirring and heat-preserved reactionfor 8 h, performing cooling with ice water after the reaction is completed, extracting a reaction solution with a carbon tetrachloride solution, conducting liquid separation, subjecting an organic phase to washing by an aqueous sulphurous acid solution with a mass fraction of 6%, an aqueous sodium hydroxide solution with a mass fraction of 12% and water in sequence, carrying out drying, evaporating an organic solution to dryness, and performing recrystallizing to obtain a yellow acicular crystal, namely the product 1,2-dichloro-4-nitrobenzene. The preparation method is simple in synthesis process, improved in product yield and mild in reaction conditions, and has practical application and promotion values.

Description

technical field [0001] The invention belongs to the technical field of compound synthesis, in particular to a preparation method of 1,2-dichloro-4-nitrobenzene. Background technique [0002] 1,2-Dichloro-4-nitrobenzene is mainly used in the synthesis of fluoroaniline, an important fluorine-containing pharmaceutical intermediate. There are two main ways to synthesize 1,2-dichloro-4-nitrobenzene: (1) Direct chlorination of p-nitrochlorobenzene: Chlorine is a commonly used chlorination agent in this type of reaction, but due to the The existence of the electron-withdrawing group-NO2 requires relatively harsh reaction conditions, which increases the number of side reactions, and the operation is relatively cumbersome, and the product yield is low; (2) Direct nitration of ortho-dichlorobenzene: use nitric acid and sulfuric acid to carry out dichlorobenzene Nitrification, yellow needle-like crystals are obtained after recrystallization with ethanol or carbon tetrachloride, but th...

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Problems solved by technology

[0003] The purpose of the present invention is to solve the existing 1,2-dichloro-4-nitrobenzene preparation method of environmental pollution, complicated steps, low yield problems, to provide a simple process, high yield, reaction Preparation method of 1,2-dichloro-4-nitrobenzene under mild conditions