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4-nitro-o-xylene continuous synthesis system and synthesis method

A technology of nitro-o-xylene and nitrification system, which is applied in the continuous synthesis system and synthesis field of 4-nitro-o-xylene, can solve the problems of poor selectivity of the target product of nitration reaction, many waste acids and inability to recycle, etc. The effect of reducing standing time and equipment volume, sufficient heat exchange area and good stirring

Active Publication Date: 2016-02-24
绍兴贝斯美化工股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The invention solves the technical problems of poor selectivity of the target product of the nitration reaction in the prior art, too much waste acid and cannot be recycled, and realizes the efficient production of 4-nitro-ortho-xylene and the production of materials through the continuous production system and production method of the present invention. Cycle through

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  • 4-nitro-o-xylene continuous synthesis system and synthesis method
  • 4-nitro-o-xylene continuous synthesis system and synthesis method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] Ortho-xylene and nitric-sulfur mixed acid are put into the mixer from their respective high-level tanks through the metering pump, wherein, in the nitric-sulfur mixed acid, the molar ratio of nitric acid to sulfuric acid is 1:0.5-1; the molar amount of nitric acid in the nitric-sulfur mixed acid Calculated, the molar ratio of o-xylene and nitric acid mixed acid is 1:1.5-2. After mixing o-xylene and nitric-sulfur mixed acid in the mixer, nitrogen is pressed into the double-ring nitration reactor, and the feed flow rate of the ortho-xylene and nitric-sulfur mixed acid mixture is 1.5-2m / s. The mixed material is pressed into the nitration system, and the organic phase and the acid phase are fully contacted to carry out multi-stage nitration reaction. The temperature in the ring-shaped nitration reactors at all levels is controlled at 10-25°C by means of heat exchangers.

[0067] The reaction solution flows out of the nitrification system and enters the first phase-separati...

Embodiment 2

[0070] Ortho-xylene and nitric-sulfur mixed acid are put into the mixer from their respective high-level tanks through the metering pump, wherein, in the nitric-sulfur mixed acid, the molar ratio of nitric acid to sulfuric acid is 1:0.1-0.44; the molar amount of nitric acid in the nitric-sulfur mixed acid Calculated, the molar ratio of o-xylene and nitric acid mixed acid is 1:1.1-2. After mixing o-xylene and nitric-sulfur mixed acid in the mixer, nitrogen is pressed into the double-ring nitration reactor, and the feed flow rate of the ortho-xylene and nitric-sulfur mixed acid mixture is 1.5-2m / s. The mixed material is pressed into the nitration system, and the organic phase and the acid phase are fully contacted to carry out multi-stage nitration reaction. The temperature in the annular nitration reactors at all levels is controlled to be 10-15° C. through heat exchangers.

[0071] The reaction solution flows out of the nitrification system and enters the first phase-separati...

Embodiment 3

[0074] Compared with Example 2, the washing system is a single-stage labyrinth washing tank. After the continuous production ends, the conversion rate of o-xylene is 90%. , sampling once every 30min), the content of 4-nitro-o-xylene is greater than 91%, and the purity of the 4-nitro-o-xylene collected by rectification is greater than 99.6% (GC area normalization method purity).

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Abstract

The invention discloses a 4-nitro-o-xylene continuous synthesis system and synthesis method. The synthesis method is characterized in that after being mixed, o-xylene and nitric-sulfuric acid are pressed in a nitration system to undergo nitration reaction; a reaction liquid enters a first split phase tank to be layered and the upper oil phase enters a washing system to undergo labyrinth washing; a washing liquid is layered in a second split phase tank, the upper liquid enters a distillation system to undergo distillation treatment and 4-nitro-o-xylene is collected. Compared with existing vertical tubular nitration reactors, dual ring shaped nitration reactors provided by the invention have the advantages that material flow splitting is carried out more uniformly, backward flow of a reaction liquid can be effectively avoided, the probability of contact between o-xylene and nitric-sulfuric acid is increased, and the raw material conversion rate is increased; the heat exchange area is fuller, and the side reaction can be effectively reduced. The production system provided by the invention has the beneficial effects that all the materials are recycled, thus reducing the production cost; the raw material conversion rate of single batch production is effectively increased, thus reducing the amount of waste acid and wastewater.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a continuous synthesis system and method for 4-nitro-o-xylene. Background technique [0002] 4-Nitro-o-xylene, formula C 8 h 9 NO 2 , molecular weight 151.16, melting point 29-31°C, boiling point 255-257°C, density 1.112g / mL, is an important intermediate of riboflavin, herbicide pendimethalin, high-energy materials and high-grade organic dyes; used as a pharmaceutical intermediate body; is the production of vitamin B by chemical synthesis 2 important raw materials. [0003] In the nitration reaction, according to the classification of nitrating reagents, it mainly includes nitration of dilute nitric acid, nitration of nitric acid mixed acid, nitration of organic nitrates and nitration of nitrogen oxides. [0004] Nitration of aromatic compounds using nitric acid as a nitrating reagent is a common method for preparing nitro compounds. If nitric acid is directly use...

Claims

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Application Information

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IPC IPC(8): C07C205/06C07C201/08C07C201/16
CPCC07C201/08C07C201/16C07C205/06
Inventor 沈亮明田园黄淑芳陈湘朋姚文斌应天祥
Owner 绍兴贝斯美化工股份有限公司