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Method for preparing 2,6-dimethoxy-3,5-diamido-pyridine hydrochloride

A technology of diaminopyridine hydrochloride and dimethoxy, applied in the field of preparation 2, can solve the problems of instability, low yield and high cost, and achieve the effects of mild reaction conditions, simple operation and stable content

Active Publication Date: 2013-05-15
辽宁新宇生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] This synthesis method produces more waste water and waste residue, and it is difficult to treat the three wastes
In addition, because the resulting reduced product has poor solubility and is extremely unstable, post-processing is difficult, and it is difficult to obtain a high-content product by this method. The product has high ash content and metal ions, and the yield is low and the cost is high.

Method used

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  • Method for preparing 2,6-dimethoxy-3,5-diamido-pyridine hydrochloride
  • Method for preparing 2,6-dimethoxy-3,5-diamido-pyridine hydrochloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Add 2,6-dimethoxy-3,5-dinitropyridine, methanol, water and 5% palladium carbon into the reactor, the weight ratio is 1:0.5:5:0.25; Replace the air with hydrogen, the amount of hydrogen introduced is 0.1~5MPa, heat the reactor until the temperature rises to 55~60°C, stop heating, naturally raise the temperature to 80~85°C, keep for 30min, keep the hydrogen pressure at 3MPa and stop feeding hydrogen , keep warm for 2 hours; after the temperature of the reactor is lowered to below 60°C, pour out the feed liquid, add hydrochloric acid to adjust the pH value to 1, filter and concentrate under reduced pressure; mix the filtrate concentrate with water and activated carbon at a ratio of 1:5:0.1 , decolorized at 60~65°C for 1 hour, then filtered activated carbon, concentrated the filtrate to dryness under reduced pressure; added the resulting filter cake to 1,4-dioxane twice its volume, dispersed and filtered, and dried the filter cake to obtain .

Embodiment 2

[0018] Add 2,6-dimethoxy-3,5-dinitropyridine, methanol, water and 5% palladium carbon into the reactor, the weight ratio is 1:1:1:0.05; Replace the air with hydrogen, and the amount of hydrogen introduced is 0.1~5MPa. Heat the reactor until the temperature rises to 55~60°C, stop heating, naturally raise the temperature to 80~85°C, keep for 40min, and keep the hydrogen pressure at 3MPa to stop feeding hydrogen , keep warm for 3 hours; after the temperature of the reactor is lowered to below 60°C, pour out the feed liquid, add hydrochloric acid to adjust the pH value to 2, filter and concentrate under reduced pressure; mix the filtrate concentrate with water and activated carbon at a ratio of 1:10:0.5 , decolorized at 60~65°C for 2 hours, then filtered activated carbon, concentrated the filtrate to dryness under reduced pressure; added the obtained filter cake to 1,4-dioxane 4 times its volume, dispersed and filtered, and dried the filter cake to obtain .

Embodiment 3

[0020] Add 2,6-dimethoxy-3,5-dinitropyridine, methanol, water and 5% palladium carbon into the reactor, the weight ratio is 1:0.8:4:0.1; Replace the air with hydrogen gas, the amount of hydrogen gas introduced is 0.1~5MPa, heat the reaction vessel until the temperature rises to 55~60°C, stop heating, naturally raise the temperature to 80~85°C, keep it for 30~40min, and keep the hydrogen pressure at 3MPa to stop the flow Add hydrogen and keep warm for 2.5 hours; after reducing the temperature of the reactor to below 60°C, pour out the feed liquid, add hydrochloric acid to adjust the pH value to 1.5, filter and concentrate under reduced pressure; mix the filtrate concentrate with water and activated carbon at a ratio of 1:5 ~10: Mix at 0.1~0.5, decolorize at 60~65℃ for 1~2h, then filter activated carbon, concentrate the filtrate to dryness under reduced pressure; add 3 times the volume of 1,4-dioxane to the obtained filter cake, and disperse Filter and dry the filter cake.

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Abstract

The invention discloses a method for preparing 2,6-dimethoxy-3,5-diamido-pyridine hydrochloride, which comprises the following steps: adding a nitration material, methyl alcohol, water and palladium carbon to a reaction kettle, introducing hydrogen into the reaction kettle to replace air, heating the reaction kettle so as to enable the temperature to rise to 55-60 DEG C, then, stopping heating, naturally heating to 80-85 DEG G, keeping for 30-40min, stopping introducing the hydrogen, and carrying out heat preservation for 2-3h; cooling the reaction kettle to at least 60 DEG C, then, pouring out feed liquid, adding hydrochloric acid, and carrying out filtration and reduced pressure condensation; mixing a filter cake with the water and active carbon, decoloring for 1-2h at the temperature of 60-65 DEG C, then, filtering the active carbon, and performing the reduced pressure condensation on a filtrate to dryness; and adding 1,4-dioxane to the filter cake, performing dispersive filtration, and drying the filter cake to obtain the 2,6-dimethoxy-3,5-diamido-pyridine hydrochloride. The method for preparing the 2,6-dimethoxy-3,5-diamido-pyridine hydrochloride has mild reaction conditions,high conversion rate and yield, high and stable content, low cost and a simple operation, and is suitable for industrial production, and no pollution is generated in the whole reaction process.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a method for preparing 2,6-dimethoxy-3,5-diaminopyridine hydrochloride. Background technique [0002] 2,6-dimethoxy-3,5-diaminopyridine hydrochloride is mainly a highly efficient oxidative hair dye, and the synthesis of 2,6-dimethoxy-3,5-diaminopyridine reported in foreign literature The method for pyridine hydrochloride mainly takes 2,6-dimethoxy-3,5-dinitropyridine as raw material and adopts stannous chloride reduction. Its synthesis principle is as follows: [0003] [0004] This kind of synthetic method produces more waste water and waste residue, and it is difficult to treat the three wastes. In addition, because the resulting reduced product has poor solubility, is extremely unstable, and is difficult to post-treat, it is difficult to obtain a product with a high content according to this method. The product has high ash content and metal ions, and the yiel...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/73
Inventor 袁顺福范洪振袁郡范琳王育军
Owner 辽宁新宇生物科技有限公司
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