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Continuous preparation method of DAB (3,3'-diaminobenzidine)

A technology for tetraaminobiphenyl and dichlorobenzidine is applied in the field of preparing 3,3',4,4'-tetraaminobiphenyl, and can solve the problems of unsuitable continuous production, large pollution, low production efficiency and the like, To achieve the effect of simplified operation, high production efficiency and short reaction time

Active Publication Date: 2015-12-02
XIANGSHUI HENRYDA TECH CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The existing reported methods are all intermittent single-pot production, the production efficiency is low, the reaction time is long, and the pollution is large, and the existing methods all adopt two kinds of The catalyst needs to be fed separately during preparation, which is troublesome to operate, and one of the two catalysts is metal powder copper, which is insoluble in water system and is not suitable for continuous production

Method used

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  • Continuous preparation method of DAB (3,3'-diaminobenzidine)

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The molten 3,3'-dichlorobenzidine is injected into the primary reactor through a high-pressure pump at a flow rate of 150 grams / hour, and the mixture of ammoniacal liquor and copper chloride with a mass fraction of 25% is injected at a flow rate of 900 grams / hour ( Among them, the flow rate of copper chloride is 6 g / hour) into the first-stage reaction kettle through the pump, and the ammoniation reaction is carried out at 0.4MPa and 140°C. The residence time of the first-stage reaction kettle is 5 minutes, and the residence time of the second-level reaction kettle is 10 Minutes, the residence time of the three-stage reactor is 5 minutes, and the reaction to be detected is complete, and the material is decompressed and discharged from the pressure-relief valve of the three-stage reactor, and the discharge is sent to a recovery device, and excess ammonia is distilled, and then separated to obtain 124.4 g / h, purity (HPLC) 98.17% of 3,3',4,4'-tetraaminobiphenyl, total yiel...

Embodiment 2

[0030] The molten 3,3'-dichlorobenzidine is injected into the primary reactor through a high-pressure pump at a flow rate of 150 g / h, and the mass fraction is 20% ammoniacal liquor and cupric chloride at a flow rate of 900 g / h (wherein The flow rate of copper chloride is 5 g / hour) into the first-stage reaction kettle through the pump, and the ammoniation reaction is carried out at 90°C. Stay for 10 minutes, until the detection reaction is complete, after depressurizing and discharging the material from the pressure reducing valve of the three-stage reactor, the material is sent to the recovery device, the excess ammonia is distilled, and then separated to obtain 122.7 g / h, purity (HPLC) 98.5% 3,3′,4,4′-tetraaminobiphenyl, the total yield is 95.3%.

Embodiment 3

[0032] The molten 3,3'-dichlorobenzidine is injected into the primary reactor through a high-pressure pump at a flow rate of 150 grams / hour, and the mass fraction is a mixture of 30% ammoniacal liquor and cupric chloride at a flow rate of 900 grams / hour (wherein The flow rate of copper chloride is 3 g / hour) pumped into the first-stage reactor for ammoniation reaction at 0.3MPa and 120°C. The first-stage reactor stays for 8 minutes, the second-stage reactor stays for 12 minutes, and the third The first-stage reactor stays for 8 minutes. After the detection reaction is complete, the material is decompressed and discharged from the pressure-relief valve of the third-stage reactor. 98.9% of 3,3′,4,4′-tetraaminobiphenyl, the total yield is 96.1%.

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Abstract

The invention relates to a continuous preparation method of DAB (3,3'-diaminobenzidine). 3,3'-dichloro-benzidine and ammonia react in water in the presence of a catalyst, DAB is obtained, copper chloride is taken as the catalyst, and excessive ammonia is added when compared with 3,3'-dichloro-benzidine. According to the method, a first-order reaction kettle, a second-order reaction kettle and a third-order reaction kettle which are connected sequentially in series are adopted, and reaction materials are continuously and sequentially added to the first-order reaction kettle, the second-order reaction kettle and the third-order reaction kettle for reaction. According to the preparation method, DAB is continuously produced, and a series of advantages of production with a continuous method are realized; meanwhile, the operation is simplified through control of production steps, selection of the catalyst and control of reaction conditions, the yield and the quality of products are guaranteed, and the cost is reduced.

Description

technical field [0001] The invention relates to a method for preparing 3,3',4,4'-tetraaminobiphenyl, in particular to a continuous preparation method for 3,3',4,4'-tetraaminobiphenyl. Background technique [0002] ′,4,4′-Tetraaminobiphenyl (DAB for short), with the structure shown in Formula I, is an important fine chemical intermediate, mainly used in the synthesis of heat-resistant polymer resins and synthetic fibers. Market demand large. [0003] [0004] Chinese patent CN201110067116.3 discloses the preparation method of 3,3′,4,4′-tetraaminobiphenyl: add 3,3′-dichlorobenzidine, copper powder and ammonia water into the autoclave, heat under stirring, React at ~250°C and pressure 0.5~8MPa for 3~6 hours, add an aqueous solution of cuprous chloride, and continue to react for 2~4 hours to obtain the crude product of 3,3′,4,4′-tetraaminobiphenyl; the crude product Add water, activated carbon and sodium dithionite, refine under nitrogen protection, crystallize out, filter ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/50C07C209/10
Inventor 张正富易元龙
Owner XIANGSHUI HENRYDA TECH CHEM