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A kind of continuous diazotization production process of aromatic amine

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

Active Publication Date: 2018-05-11
ZHEJIANG LONGSHENG GROUP +2
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  • Abstract
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  • 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

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  • A kind of continuous diazotization production process of aromatic amine

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Experimental program
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Effect test

Embodiment 1

[0024] Using two tanks in series continuous diazonium mode, the effective volume of a single tank is 3M 3 , With a cooling jacket outside and a cooling coil inside, the single-pot reaction liquid level is set to about 90% of the effective volume, and the reaction residence time is about 3 hours.

[0025] Put the previously synthesized diazonium salt solution as the bottom material into two diazonium reaction kettles, add 60% of the full liquid level, turn on the stirring, and pass frozen brine into the jacket and cooling coil. The powdered 2,4-dinitro-6-bromoaniline raw material is added to the weighing and feeding system silo, the feeding speed is controlled by the motor speed of the screw feeder, and the weight is detected by the loss-in-weight load cell. The feed rate in the nitrogen reactor is 180kg / h. At the same time, according to the molar ratio of aromatic amine, sulfuric acid, and nitrosyl sulfuric acid of 1:2:1.03, the feed rate of 98% sulfuric acid is determined to be 1...

Embodiment 2

[0034] Three tanks in series and continuous diazonium mode are adopted, and the effective volume of single tank is 3m 3 , The first and second stage kettles are equipped with cooling jackets and cooling coils inside; the third stage kettles are jacketed outside; 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] Put the previously synthesized diazonium salt solution as the bottom material into three diazonium reaction kettles, add 60% of the full liquid level, turn on the stirring, and pass frozen brine into the jacket and cooling coil. The powdered 2,6-dichloro-4-nitroaniline material is added to the weighing and feeding system silo, the feeding speed is controlled by the motor speed of the screw feeder, and the weight is detected by the loss-in-weight load cell. The feed rate in the nitrogen reactor is 165kg / h. At the same time, according to the molar ratio of aromatic amine, su...

Embodiment 3

[0044] The granular p-nitroaniline is pulverized by a pulverizer and passed through a 50-mesh vibrating sieve for use;

[0045] Two reactors in series are used for continuous diazonium, and the effective volume of a single reactor is 3m 3 , With external cooling jacket, internal cooling coil, single tank reaction liquid level is set to about 90% of the effective volume, reaction residence time is about 2.5 hours.

[0046] Put the previously synthesized diazonium salt solution as the bottom material into two diazonium reaction kettles, add 58% of the full liquid level, turn on the stirring, and pass frozen brine into the jacket and cooling coil. The crushed p-nitroaniline raw materials are added to the weighing and feeding system silo, the feeding speed is controlled by the motor speed of the screw feeder, and the feeding amount added to the first-level diazo reactor is detected by the loss-in-weight weighing sensor At the same time, according to the molar ratio of aromatic amine, s...

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Abstract

The invention provides a continuous diazotization production process for aromatic amines. The process is as follows: adopt multi-stage series-connected diazo reaction kettles, put powdered aromatic amine raw materials into the feed bin of the feeding system, and use a weighing device to The feeding system and solid raw materials are weighed as a whole, and the aromatic amine is continuously and stably added to the diazo reactor through the automatic feeder. The difference method is used to calculate the dosage of the aromatic amine raw material per unit time, according to The molar ratio of aromatic amine, sulfuric acid and nitrosyl sulfuric acid is 1: (1~5): (1.01~1.10), and the nitrosyl sulfuric acid and sulfuric acid are fed continuously and stably through the liquid metering and regulating device. Add it to the diazotization kettle, and control the temperature under stirring to carry out the diazotization reaction at 0~40°C. The invention makes industrial large-scale production possible. By improving the traditional batch feeding method of raw materials, accurately controlling the proportion of reaction raw materials, reaction temperature and reaction time, the yield of diazonium salt is improved, the quality of diazonium salt is stabilized, and the batch difference is reduced. .

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 for dye synthesis. (2) Background technology [0002] The reaction of primary aromatic amine with nitrous acid in the presence of inorganic acid to form diazonium salt 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, and explosives. , Photosensitive materials, dyes and other organic synthesis processes, especially in the dye industry, more than 60% of products are produced through diazotization. [0003] The traditional diazonium salt production process is usually carried out by the cis-feeding method, for example, the sodium nitrite is added dropwise to the diazonium component hydrochloric acid (or sulfuric acid) solution or suspension for diazotization. The above me...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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