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Clean technology for continuously synthesizing 2,6-dichloro-p-nitroaniline

A technology for the synthesis of p-nitroaniline, applied in the preparation of organic compounds, preparation of amino compounds, organic chemistry, etc., to achieve significant economic and social benefits, reduce the amount of hydrochloric acid, and achieve effective treatment and comprehensive utilization of resources

Active Publication Date: 2016-04-06
ZHEJIANG LONGSHENG GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This production process can increase output and reduce production cost, but the hydrogen chloride gas in the tail gas absorption tower and the mother liquor after material pressure filtration need subsequent treatment

Method used

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  • Clean technology for continuously synthesizing 2,6-dichloro-p-nitroaniline
  • Clean technology for continuously synthesizing 2,6-dichloro-p-nitroaniline
  • Clean technology for continuously synthesizing 2,6-dichloro-p-nitroaniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Continuous synthesis:

[0044] Such as figure 1 , using three-stage series reactors (2, 3, 4), three parallel filter presses (8, 9, 10) and two parallel mother liquor recovery tanks (11, 12), the first, second, and third stages The volume of the reactor is 50m 3 , control the chlorination temperature at 40-45°C, and the volume of the mother liquor recovery tank is 50m 3 , the volume of the filter press is 400m 3 , the volume of the mother liquor storage tank is 100m 3 , The liquid level of the mother liquid recovery tank is set to 90% of the volume.

[0045]In the beating kettle (1), feed raw materials simultaneously and continuously for beating, control the feed rate of p-nitroaniline to be 690kg / h, and the feed rate of 31% hydrochloric acid to be 7065kg / h, and the material in the beating kettle (1) Enter the primary reaction still (2) with the speed of 7755kg / h again; A part of the pump is self-circulating, and a part enters the secondary reactor (3) at a flow r...

Embodiment 2

[0050] According to the operation method described in Example 1, only the hydrochloric acid is replaced with the mother liquor in the mother liquor storage tank, and the filter cake from the filter press is washed and dried to obtain the 2,6-dichloro-p-nitro Aniline, measured purity (HPLC) 98.4%, yield 96.9%. The collected HCl gas is used for the synthesis of m-acetaniline, and the purity (HPLC) of 99% m-acetaniline can be obtained.

Embodiment 3

[0052] Continuous synthesis:

[0053] By the continuous synthesis operation method described in embodiment 1, the difference is the flow rate of raw materials: the feed rate of p-nitroaniline is 552kg / h, and the feed rate of 29% hydrochloric acid is 5790kg / h, the beating still The material enters the first-stage reactor at a rate of 6342kg / h; the chlorine gas is passed into the first-stage reactor at a flow rate of 525kg / h through the injector, and the material of the upper-stage reactor is passed into the next-stage reactor at a flow rate of 6867kg / h Reactor; then pumped into the filter press to filter at a flow rate of 6867kg / h, and the filter press also entered the mother liquor recovery tank at a flow rate of 6867kg / h; air was blown in the mother liquor recovery tank, and when the concentration of hydrochloric acid was 29%, the drum was stopped Air, the mother liquor enters the mother liquor storage tank, and the hydrogen chloride tail gas is collected at the same time; th...

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Abstract

A clean technology for continuously synthesizing 2,6-dichloro-p-nitroaniline adopts multistage serially connected reaction kettles and comprises the following steps: continuously adding 2,4-dinitroaniline, hydrochloric acid and chlorine to a first stage reaction kettle, carrying out a chlorination reaction under stirring, allowing parts of a material in a previous reaction kettle to enter a self reaction kettle through a pump and to circulate, allowing parts of the material in the previous reaction kettle to enter a next reaction kettle, continuously carrying out the chlorination reaction, allowing tail gas generated in the previous reaction kettle to enter the next reaction kettle, continuously carrying out the chlorination reaction, allowing parts of a material in a final stage reaction kettle to enter the self reaction kettle through a pump and to circulate, continuously discharging and filtering parts of the final obtained material after a detection result shows the reaction is completed to obtain a filter cake which is a 2,6-dichloro-p-nitroaniline product, allowing a mother liquor obtained after filtration to enter a mother liquor recovery tank, blowing air to the mother liquor in the mother liquor recovery tank, reusing hydrogen chloride tail gas obtained after blowing, pumping the blown mother liquor with certain acidity into a mother liquor storage tank, and recycling the mother liquor in the mother liquor storage tank to substitute hydrochloric acid.

Description

(1) Technical field [0001] The invention relates to a cleaning process for synthesizing 2,6-dichloro-p-nitroaniline, in particular to a cleaning process for continuously synthesizing 2,6-dichloro-p-nitroaniline. (2) Background technology [0002] 2,6-Dichloro-p-nitroaniline is an important dye intermediate, which is used for the synthesis of disperse dyes such as disperse yellow brown 3GL, decomposed yellow brown 2RFL, disperse brown 3R, and disperse brown 5R. The synthesis methods are mainly as follows : [0003] (1) direct chlorination method [0004] [0005] P-nitroaniline is obtained by reacting with chlorine gas at 35°C under the condition of hydrochloric acid. Although the method is cheap and easy to obtain raw materials, the yield is 95%, and the purity is more than 98%, but the hydrogen chloride tail gas needs to be recovered and treated. [0006] (2) Sodium chlorate method [0007] [0008] p-Nitroaniline is obtained by reacting with sodium chlorate at 20...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/74
Inventor 余青结曾银城祝培明陆军李世华张桂香周俊锋倪松涛
Owner ZHEJIANG LONGSHENG GROUP
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