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Continuous diazotization production process of aromatic amine

A production process, technology of aromatic amines, applied in the field of continuous diazotization production process of aromatic amines, can solve the problems of low production efficiency, poor working environment, unstable reaction conditions, etc., to reduce batch difference and improve utilization rate , The effect of shortening the production time

Active Publication Date: 2014-03-26
ZHEJIANG LONGSHENG GROUP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] The above-mentioned continuous process basically revolves around the diazotization process of the nitrite method, which is inconsistent with the current production status of the nitrosyl sulfate diazonium method for disperse dyes. The current nitrosyl sulfate diazonium method mostly uses intermittent reverse feeding, but this method exists There are disadvantages such as unstable reaction conditions, low production efficiency, and poor working environment, and the technology to solve the above disadvantages through continuous process has not been reported

Method used

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  • Continuous diazotization production process of aromatic amine

Examples

Experimental program
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Effect test

Embodiment 1

[0024] The continuous diazo method of two kettles in series is adopted, and the effective volume of a single kettle is 3M3 , with a cooling jacket outside and a cooling coil inside, the liquid level of the single-pot reaction is set to about 90% of the effective volume, and the reaction residence time is about 3 hours.

[0025] Add the previous batch of diazonium salt solution synthesized as base material into two diazonium reaction kettles, the amount added is 60% of the full liquid level, start stirring, and feed frozen brine into the jacket and cooling coil, The powdery 2,4-dinitro-6-bromoaniline raw material is added to the silo of the weighing feeding system, the feeding speed is controlled by the motor speed of the screw feeder, and added to the primary weight after being detected by the weight-loss type load cell. The feed rate in the nitrogen reactor is 180kg / h. At the same time, according to the feed molar ratio of aromatic amine, sulfuric acid, and nitrosyl sulfuric a...

Embodiment 2

[0034] The continuous diazo method of three kettles in series is adopted, and the effective volume of a single kettle is 3m 3 , The first and second-stage kettles are equipped with cooling jackets and cooling coils inside; the third-stage kettles are equipped with jackets; the reaction liquid level of the single kettle is set to about 90% of the effective volume, and the reaction residence time is about 2.5 hours.

[0035] Add the previous batch of synthesized diazonium salt solution as base material into three diazonium reaction kettles, the amount added is 60% of the full liquid level, start stirring, and feed frozen brine into the jacket and cooling coil. The powdered 2,6-dichloro-4-nitroaniline raw material is added to the silo of the weighing feeding system, the feeding speed is controlled by the motor speed of the screw feeder, and added to the primary weight after being detected by the weight loss type weighing sensor. The feed rate in the nitrogen reactor is 165kg / h. A...

Embodiment 3

[0044] Granular p-nitroaniline is first pulverized by a pulverizer, and passed through a 50-mesh vibrating sieve for subsequent use;

[0045] The continuous diazo method of two kettles in series is adopted, and the effective volume of a single kettle is 3m 3 , with a cooling jacket outside and a cooling coil inside, the liquid level of the single-pot reaction is set to about 90% of the effective volume, and the reaction residence time is about 2.5 hours.

[0046] Add the previous batch of synthesized diazonium salt solution as the bottom material into two diazonium reaction kettles, the amount added is 58% of the full liquid level, start stirring, and feed frozen brine into the jacket and cooling coil. The pulverized p-nitroaniline raw material is fed into the silo of the weighing feeding system, the feeding speed is controlled by the motor speed of the screw feeder, and the feeding amount added to the primary diazonium reactor is detected by the weight loss sensor At the sam...

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Abstract

The invention provides a continuous diazotization production process of aromatic amine. The process is as follows: by utilizing a multistage serially connected diazotization reaction kettle, throwing a powdery aromatic amine raw material into a stock bin of a feeding system, integrally weighing the feeding system and the solid raw material through a weighing device, continuously and stably adding the aromatic amine into the diazotization reaction kettle through an automatic feeder, calculating the feeding dosage of the aromatic amine raw material within a unit time through a difference method, continuously and stably adding nitrosyl sulfuric acid and sulfuric acid into the diazotization reaction kettle according to a feeding molar ratio of the aromatic amine, the sulfuric acid and the nitrosyl sulfuric acid of 1:(1-5): (1.01-1.10) through a liquid metering and adjusting device, stirring and controlling the temperature to 0-40 DEG C to carry out a diazotization reaction. By adopting the continuous diazotization production process disclosed by the invention, industrial large-scale production becomes possible, the traditional intermittent dosing method of raw materials is improved, the reaction raw material proportion, the reaction temperature and the reaction time are accurately controlled to improve the diazonium salt yield, stabilize the diazonium salt quality and reduce the color differences between lots.

Description

(1) Technical field [0001] The invention relates to a continuous diazotization production process of aromatic amines, in particular to a continuous diazotization production process of aromatic amines used for dye synthesis. (2) Background technology [0002] In the presence of inorganic acids, primary aramide reacts with nitrous acid to form diazonium salt, which is called diazotization reaction. The product diazonium salt is an important intermediate for the synthesis of azo compounds, and is widely used in medicine, pesticides, explosives , photosensitive materials, dyes and other organic synthesis processes, especially in the dye industry, more than 60% of the products are produced through diazotization reactions. [0003] The traditional diazonium salt production process usually adopts the cis-feeding method, such as adding sodium nitrite dropwise to the diazonium component hydrochloric acid (or sulfuric acid) solution or suspension for diazotization. The above method ha...

Claims

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Application Information

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IPC IPC(8): C07C245/20
Inventor 何旭斌陶建国孟明朱敬鑫杨伟军李建勋黄洪松
Owner ZHEJIANG LONGSHENG GROUP
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