Method and specially used apparatus for ortho-dichlorobenzene continuous mononitration reaction

Abstract

The invention discloses a method and specially used apparatus for ortho-dichlorobenzene continuous mononitration reaction. The method is characterized in that raw materials are added into an ortho-dichlorobenzene metering tank; a nitrating agent A is added into a nitrating agent A metering tank; the raw materials and the nitrating agent A are separately input into a first mixer synchronously through a first metering pump and a second metering pump; a reaction is performed at a temperature of 100-200 DEG C for 15-50 min; a reaction solution A enters a first liquid separation device; after liquid separation, an organic phase A enters a second mixer and an inorganic phase A enters a waste acid receiving device; a nitrating agent B stored in a nitrating agent B metering tank is added into the second mixer through a third metering pump; a nitration reaction is performed in a second tube reactor at a temperature of 10-100 DEG C; a reaction solution B enters a second liquid separation device; after liquid separation, an inorganic phase B enters the waste acid receiving device and an organic phase B enters a product postprocessing device for obtaining a mononitration product. The concentration of sulfuric acid used in the preparation method provided by the invention is low, the raw material conversion is complete, the yield of the final product is high, multi-nitro by-products are less, and the safety is higher, so that the preparation method and the apparatus are suitable for industrialized production.

Description

(1) Technical field [0001] The invention relates to a method and a special device for continuous mononitration reaction of o-dichlorobenzene. (2) Background technology [0002] The mononitration products of o-dichlorobenzene, 2,3-dichloronitrobenzene and 3,4-dichloronitrobenzene, are important pharmaceutical and chemical intermediates, often used in the preparation of third-generation "fluoroquinolones" drugs, antihypertensive Blood pressure drugs, etc., can also be used to synthesize plant protection agents and fuels. [0003] The methods reported in the literature for o-dichlorobenzene mononitration reaction can be divided into three categories: (1) mixed acid isothermal nitration method: Cheng Xiulian et al. (Journal of Shenyang Institute of Technology, 1998, 1:104-108.) Under certain conditions, the method for preparing mononitro-ortho-dichlorobenzene by dropwise adding mixed acid composed of sulfuric acid / nitric acid to o-dichlorobenzene has a yield of 94.8% and a GC p...

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Problems solved by technology

[0004] Among the above methods, mixed acid nitration is a commonly used method in industry. The nitration reaction is a strong exothermic reaction. The traditional kettle-type process exists: the mass transfer and heat transfer efficiency of the reactor is low, and it is easy to cause high local concentration and temperature, and produce di-nitration by-products , but the content of dinitro impurities is high, it is easy to explode during the subsequent rectification operation, and there are many problems such as potential safety hazards

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