Method for preparing o-nitroanisole and p-nitroanisole from mixed nitrochlorobenzene

Abstract

The invention relates to a method for preparing o-nitroanisole and p-nitroanisole from mixed nitrochlorobenzene. According to the invention, mixed nitrochlorobenzene consisting of a product obtained after nitration of chlorobenzene, o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene is used as a raw material, and in a methanol system, 30% of alkali lye and a phase-transfer catalyst are added for a reaction to prepare products of o-nitroanisole and p-nitroanisole, wherein m-nitrochlorobenzene does not participate in the reaction. The method provided by the invention overcomes the problems of great investment for rectifying tower equipment, great energy consumption in rectification, high cost, long process flow, harsh operation conditions, poor operational safety performances and generation of waste residues hardly to treat in rectification-crystallization separation of mixed nitrochlorobenzene in conventional production processes for o-nitroanisole and p-nitroanisole and overcomes the technical problems of generation of considerable alkaline waste water containing sodium hyposulfite and production of a poor-quality product in a sodium sulfide reduction process.

Description

technical field [0001] The present invention relates to the technical field of preparation methods of o-nitroanisole and p-nitroanisole, in particular to a product obtained by nitration of chlorobenzene, o-p-nitrochlorinated benzene, m-p-nitrochlorinated benzene and P-nitrochlorinated benzene is a method for preparing o-nitroanisole and p-nitroanisole by mixing nitrochlorinated benzene as a raw material. Background technique [0002] o-Nitroanisole and p-Nitroanisole are important organic intermediates. The key step to produce nitrophenyl ether with chlorobenzene as raw material is to produce nitrochlorobenzene mixture through mixed acid nitration reaction, nitrochlorobenzene mixture After rectification-crystallization separation, o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene are obtained, and then they are further processed by etherification to obtain the corresponding nitrophenyl ether products. Although there are mature processes and "three wastes" ...

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Problems solved by technology

[0003] The technical problem to be solved in the present invention is: in order to solve the existing o-nitroanisole and p-nitroanisole production process, rectification tower equipment investment is big, rectification energy consumption is big, and cost is high, and process flow is long, The operating conditions are harsh, the operating safety performance is poor, and the mixed nitrochlorobenzene undergoes rectification-crystallization separation operations to produce difficult-to-handle waste residues; at the same time, the use of alkali sulfide reduction process produces a large amount of alkaline wastewater containing sodium thiosulfate. The technical problem of poor quality, the present invention provides a kind of product obtained by nitration with chlorobenzene, ortho-p-nitrochlorinated benzene, m-p-nitrochlorinated benzene and p-nitrochlorinated benzene, this mixed nitrochlorinated benzene A method for preparing o-nitroanisole and p-nitroanisole as a raw material, the method has a simple process and a high conversion rate; the process is clean and environmentally friendly; the three wastes are less polluted

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