Micro-channel synthesis method of dinitrobenzene

A synthesis method and technology of dinitrobenzene, applied in the direction of nitro compound preparation, organic chemistry, etc., to achieve process safety and reduce the effect of possibility

Inactive Publication Date: 2020-04-17
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The present invention is based on micro-reactor synthesis technology, using benzene to synthesize dinitrobenzene in one step, which has not been reported

Method used

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  • Micro-channel synthesis method of dinitrobenzene
  • Micro-channel synthesis method of dinitrobenzene
  • Micro-channel synthesis method of dinitrobenzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～6

[0044] Fuming nitric acid (≥98%) and concentrated sulfuric acid (≥98%) are used to prepare a mixed acid with a molar ratio of fuming nitric acid and concentrated sulfuric acid of 0.5 and a water concentration of 3%. During the preparation of mixed acid, the temperature can be controlled below 25°C. Under normal temperature conditions, the mixed acid and benzene are continuously pumped into the micro-reactor by the micro-advection pump and react in the micro-reaction channel, and the reaction temperatures are 60°C, 70°C and 80°C respectively. Control the molar ratio of nitric acid and benzene to be ≥ 2.0 and ≤ 2.4. The specific conditions of the microreactor reaction are shown in Table 1.

[0045] Table 1

[0046]

[0047] The reaction product flows out of the reactor continuously, enters the collector and maintains the same reaction temperature as the microreactor for 1 hour, then the reaction material enters the separator and adds an appropriate amount of ice water to te...

Embodiment 13～24

[0050] The process and the reactor used are the same as in Examples 1-5, the molar ratio of nitric acid to sulfuric acid is 0.5, the water content in the mixed acid is 2%, 8% and 10% respectively, the molar ratio of nitric acid to benzene is ≥2.0, and ≤2.4, micro-reaction The receiver and collector were operated at 70°C. The reaction conditions of the microreactor are shown in Table 2. The implementation results are attached image 3 Show.

[0051]

[0052] From image 3 It can be seen that with the increase of N / B, the content of dinitrobenzene increases, which is beneficial to the nitration reaction. The water content in the mixed acid increases, the nitration ability of the mixed acid decreases, and the content of dinitrobenzene decreases.

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Abstract

The invention relates to a synthetic method of dinitrobenzene in a micro-channel reactor. The method comprises the following steps: (1) preparing a mixed acid solution of nitric acid and sulfuric acidat a molar ratio of 0.2-1.0; (2) respectively and simultaneously conveying initial reactants benzene and the mixed acid solution into two inlets of the micro-reactor by a metering pump; (3) mixing reactant benzene and the mixed acid solution in the micro-channel reactor and reacting, wherein the reaction residence time is 8-500 seconds; (4) outputting an obtained reaction material to a collectorfrom a channel of the micro-reactor, and continuously carrying out heat-preservation stirring reaction for 0-1 hour; and separating, washing and drying on the basis of a conventional method to obtaina target product. According to the method, dinitrobenzene synthesis is achieved through the efficient mass and heat transfer capacity of the micro-channel reactor, the process is safe and efficient, the conversion rate is close to 100% under the optimized condition, the yield of the obtained dinitrobenzene is higher than 99%, and the yield of the main product 1, 3-dinitrobenzene reaches 84%.

Description

technical field [0001] The invention relates to a synthesis method of important fine chemicals, in particular to a synthesis method of dinitrobenzene in a microchannel reactor. Background technique [0002] Dinitrobenzene is an important raw material in chemical production, mainly used in the preparation of dyes, paints, and coatings, and is also a precursor for the production of explosive trinitrobenzene (TNT). [0003] The production of dinitrobenzene mainly includes two-step nitration of benzene and one-step nitration of nitrobenzene. At present, the nitrification process is mainly divided into two kinds of nitrification processes: isothermal nitrification and adiabatic nitrification. The difference is mainly in the way of energy transfer and waste acid recovery, which mainly leads to different energy consumption and different components of nitrification products. Constant temperature conditions are conducive to product selectivity, and adiabatic conditions can integrate...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/08C07C205/06
CPCC07C201/08C07C205/06
Inventor 陈光文廉应江焦凤军韩梅
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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