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A method for preparing 4,6-dihydroxypyrimidine

A technology of dihydroxypyrimidine and hydroxypyrimidine disodium salt, which is applied in the field of 4,6-dihydroxypyrimidine synthesis, can solve the problems that 4,6-dihydroxypyrimidine cannot be recycled, difficult wastewater treatment, solid waste of activated carbon, etc. To achieve the effect of avoiding solid waste of activated carbon, solving difficult to handle, and reducing the content of organic matter

Active Publication Date: 2021-12-14
潍坊滨海石油化工有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The above-mentioned process mainly has the following problems: (1): The solubility of 4,6-dihydroxypyrimidine in acidified wastewater is relatively large, about 0.45%, and the wastewater produced by each ton of 4,6-dihydroxypyrimidine contains about 45kg Finished product; (2): Wastewater treatment is more difficult. Since the waste water contains more products, the products are continuously decomposed during the process of steaming methanol and formic acid, resulting in a large amount of organic matter with heavy color in the by-product sodium chloride, which needs to be added in a large amount Only by decolorizing activated carbon can the by-product sodium chloride with qualified chromaticity and organic matter content be obtained, but this operation produces activated carbon solid waste; (3) 4,6-dihydroxypyrimidine dissolved in acidified wastewater cannot be recycled
However, the amount of by-product waste water per ton of product in this operation is also more than 9 tons, and the dissolution loss of the product is still very large, and the 4,6-dihydroxypyrimidine in the acidified waste water has not been recovered.

Method used

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  • A method for preparing 4,6-dihydroxypyrimidine
  • A method for preparing 4,6-dihydroxypyrimidine
  • A method for preparing 4,6-dihydroxypyrimidine

Examples

Experimental program
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Effect test

Embodiment 1

[0039] (1) Add 12,600kg of methanol solution containing 30%wt sodium methoxide to a 20,000L reactor, then add 2,172kg of formamide, raise the temperature to 65°C, then start to drop 2,610kg of dimethyl malonate, and control the reaction temperature at 60°C, After the dropwise addition, keep warm for 5 hours;

[0040] (2) Cool down to 30°C, add 10080kg of water, and stir for 1 hour to dissolve 4,6-dihydroxypyrimidine disodium salt;

[0041] (3) Continuously add the fully dissolved reaction solution into the alcohol distillation tower, recover anhydrous methanol from the top of the tower, and continuously discharge the solution containing 4,6-dihydroxypyrimidine disodium salt from the bottom of the tower;

[0042] (4) Add 30%wt hydrochloric acid to the solution containing 4,6-dihydroxypyrimidine disodium salt discharged from the tower kettle for acidification. Dihydroxypyrimidine, centrifuged to obtain 4,6-dihydroxypyrimidine solid wet material and sodium chloride acidification...

Embodiment 2

[0049] (1) Add 12,600kg of methanol solution containing 30%wt sodium methoxide to a 20,000L reactor, then add 2,175kg of formamide, raise the temperature to 65°C, then start adding 2,620kg of dimethyl malonate dropwise, and control the reaction temperature at 65°C. After the dropwise addition, keep warm for 4 hours;

[0050] (2) Cool down to 35°C, add 9000kg of water, and stir for 2 hours to dissolve 4,6-dihydroxypyrimidine disodium salt;

[0051] (3) Continuously add the fully dissolved reaction solution into the alcohol distillation tower, recover anhydrous methanol from the top of the tower, and continuously discharge the solution containing 4,6-dihydroxypyrimidine disodium salt from the bottom of the tower;

[0052] (4) Add 20%wt hydrochloric acid to the solution containing 4,6-dihydroxypyrimidine disodium salt discharged from the tower kettle for acidification. Dihydroxypyrimidine, centrifuged to obtain 4,6-dihydroxypyrimidine solid wet material and sodium chloride acidifi...

Embodiment 3

[0059] (1) Add 12,600kg of methanol solution containing 30%wt sodium methoxide to a 20,000L reactor, then add 2,175kg of formamide, raise the temperature to 65°C, then start adding 2,626kg of dimethyl malonate dropwise, and control the reaction temperature at 70°C. After the dropwise addition, the insulation was kept for 4.5 hours;

[0060] (2) Cool down to 33°C, add 8000kg of water, and stir for 0.5 hours to dissolve 4,6-dihydroxypyrimidine disodium salt;

[0061] (3) Continuously add the fully dissolved reaction solution into the alcohol distillation tower, recover anhydrous methanol from the top of the tower, and continuously discharge the solution containing 4,6-dihydroxypyrimidine disodium salt from the bottom of the tower;

[0062] (4) Add 28%wt hydrochloric acid to the solution containing 4,6-dihydroxypyrimidine disodium salt for acidification, the acidification temperature is 40°C, acidify to pH 3-4, precipitate 4,6-dihydroxypyrimidine, centrifuge Filter to get 4,6-di...

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Abstract

The invention belongs to the technical field of 4,6-dihydroxypyrimidine synthesis, and specifically relates to a method for preparing 4,6-dihydroxypyrimidine, comprising the following steps: (1) cyclization reaction; (2) cooling and dissolution; (3) ) Alcohol distillation under reduced pressure; (4) Acidification and separation; (5) Washing; (6) Adsorption; (7) Recovery of formic acid; (8) Recovery of sodium chloride; (9) Analysis. The method provided by the invention absorbs 4,6-dihydroxypyrimidine in the acidified wastewater through the adsorption resin, which not only improves the product yield, reduces the content of organic matter in the wastewater, solves the disadvantage of difficult wastewater treatment, but also improves the by-product The quality of sodium chloride reduces the content of organic matter in the by-product salt, which has good economic and social benefits.

Description

technical field [0001] The invention belongs to the technical field of 4,6-dihydroxypyrimidine synthesis, and specifically relates to a method for preparing 4,6-dihydroxypyrimidine. Background technique [0002] 4,6-Dihydroxypyrimidine is an intermediate for the production of sulfa drugs, vitamin B4, and antineoplastic drugs, and is also a key intermediate for the fungicide azoxystrobin, and has a wide market demand. [0003] The current industrial production method of 4,6-dihydroxypyrimidine is to react dimethyl malonate and formamide in sodium methoxide methanol solution to generate 4,6-dihydroxypyrimidine disodium salt. After the reaction is complete, remove part of the methanol below 60°C, add quantitative water to dissolve, then neutralize with hydrochloric acid to a pH of about 2, and filter to obtain 4,6-dihydroxypyrimidine. The acidified mother liquor is sequentially distilled to remove the remaining azeotrope of methanol, formic acid and water, and the still liquor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D239/54
CPCC07D239/54
Inventor 王丽窦荣坦杨文涛王龙富张均盈李茂春刘娟
Owner 潍坊滨海石油化工有限公司
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