Refining process of paranitrobenzoyl chloride intermediate

Abstract

The invention provides a refining process of a paranitrobenzoyl chloride intermediate. The refining process comprises the following steps that a xylene solution is added to a reaction kettle, then paranitrotoluene is added to the xylene solution, air is fed into the reaction kettle, and sodium dichromate is added to the reaction kettle; concentrated sulfuric acid is drop added to the reaction kettle; stirring of the reaction kettle is stopped, an NaOH solution is added to the reaction kettle until the PH of the reaction kettle is 7; the solution is transferred to a rectifying kettle, the heated solution is heated, nitrogen is fed for exhausting, then the solution after exhausting is cooled, and crystallization is performed, so that the paranitrobenzoyl chloride intermediate is obtained. With the adoption of the production process, the process is simpler, control is easy, the production amount of impurities is reduced in the production process, the reaction time is saved, and accordingly, the production efficiency is improved.

Description

technical field [0001] The invention relates to the field of plastic fine chemical production, in particular to a method for refining p-nitrobenzoyl chloride intermediates. Background technique [0002] p-Nitrobenzoyl chloride is a medical raw material used to prepare procaine hydrochloride, p-aminobenzoyl glutamic acid and folic acid, etc.; it can be used as a dye raw material to prepare direct dye brown 100 for leather and paper; It can be used to make acid dyes, food additives (milk powder conditioners), color developing agents and organic synthesis intermediates, identification of alcohols, phenolic reagents, etc. [0003] p-Nitrobenzoyl chloride is an important intermediate in the synthesis of folic acid, procaine hydrochloride, N-p-aminobenzoyl-L-glutamic acid and other vitamin pharmaceutical products, and is also widely used in the production of pigments and color developers . Especially in recent years, with the rise of the feed industry and the development of the ...

AI Technical Summary

Problems solved by technology

There are certain deficiencies in the existing several preparation methods: as phosgene and phosphorus oxychloride are highly toxic substances, it is easy to cause harm to personnel safety and the environment; phosphorus pentachloride is a solid, and it is necessary to add a solvent to accelerate the reaction, which is easy Increase impurities and separation operations; when thionyl chloride is used as the chlorination agent, the reaction time is longer, and column distillation is required to remove impurities, increasing energy consumption, etc.

[0005] The existing production process of p-nitrobenzoic acid, an intermediate of p-nitrobenzoyl chloride, is relatively complicated, difficult to control, and generates more impurities, longer reaction time, and lower product purity