Micro-reaction equipment and method for preparing 2-nitro-4-methylsulfonyl toluene

Abstract

The invention relates to micro-reaction equipment and method for preparing 2-nitro-4-methylsulfonyl toluene. The equipment comprises a feeding device, a micro-reaction device and a material collecting device, the feeding device is communicated with the micro-reaction device, the micro-reaction device is communicated with the material collecting device, the micro-reaction device comprises a micro-reactor, the micro-reactor is a micro-dispersion type reactor, and comprises a dispersion phase inlet, a continuous phase inlet, a dispersion phase communication path, a dispersion medium film, a continuous communication path, a mixing path and a reaction liquid path, concentrated nitric acid is dispersed into tiny liquid drops through the dispersion phase communication path and the dispersion medium film and enters the mixing path, and raw material liquid enters the mixing path through the continuous communication path, and is fully mixed with concentrated nitric acid in the mixing passage, and completes nitration reaction in the micro-reaction device to generate a reaction product. The scheme provided by the invention has the advantages of low acid consumption, small material retention amount, high reaction efficiency, easiness in amplification, safety, reliability and the like.

Description

technical field [0001] The invention belongs to the technical field of 2-nitro-4-methylsulfonyltoluene synthesis, and relates to a micro-reaction device and method for preparing 2-nitro-4-methylsulfonyltoluene. Background technique [0002] 2-Nitro-4-methylsulfonyl toluene is an important intermediate for the preparation of the herbicide mesotrione, and an important raw material for the synthesis of the chemical intermediate 2-nitro-4-methylsulfonyl benzoic acid. It is also used as a medicine. , The intermediate of dyestuff is an important chemical raw material, and the market demand is huge. [0003] 2-Nitro-4-methylsulfonyltoluene is synthesized from 4-methylsulfonyltoluene by the mixed acid nitration of nitric acid-concentrated sulfuric acid. The reaction heat of mixed acid nitration is very large, and the reaction heat of adding a nitro group to the benzene ring is about 150KJ / mol, so this reaction process belongs to the production process of hazardous chemicals. At pr...

AI Technical Summary

Problems solved by technology

At present, the preparation of 2-nitro-4-thiamphenicol toluene at home and abroad is mostly carried out by batch production, that is, p-thiamphenicol toluene and concentrated sulfuric acid are added to the stirred tank, the reaction temperature is controlled, and under the condition of constant stirring , slowly drop nitric acid, after the nitric acid dropwise addition is completed, keep warm until the reaction finishes; Low efficiency; (2) The mass transfer and heat transfer effects of the stirred tank are poor, which can easily lead to uneven mixing of materials, resulting in local overheating and side reactions; (3) The process is easy to get out of control, and there are great safety hazards

[0004] The Chinese patent application number is 201911201477.5 and the patent application publication number is CN 110845373A discloses a method for the continuous preparation of 2-nitro-4-thiamphenicol toluene. The method is used in series by n-stage nitration retention tanks to realize 2- The continuous industrial production of nitro-4-thiamphenicol toluene has the advantages of precise control of the feeding ratio and reaction time, but the production equipment is still dominated by stirred tanks, and the multi-stage stirred tanks are connected in series, covering a large area

[0005] The CN110759837A patent published in 2020 introduced a new method for the continuous production of 2-nitro-4-thiamphenicol toluene. This method replaces the traditional stirred tank reactor with a microchannel reactor, and realizes temperature, material distribution While conditions such as residence time are accurately controlled, the liquid holding capacity of the reactor is reduced, and the safety of the process is improved; however, the channel size of the microchannel reactor is in the micron level, and when the total flow rate of the material is 20ml / min, the system pressure It is already close to 2mpa. In order to ensure that the pressure drop caused by the mixing of the two materials will not exceed the pressure range that the feed pump and the microchannel reactor can withstand, the total flow rate of the materials must be controlled within a lower range, and the single-channel processing capacity is small.

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