A post-processing method for synthesizing 4,6-dihydroxypyrimidine

A technology of dihydroxypyrimidine and dimethyl malonate, applied in the direction of organic chemistry and the like, can solve the problems of high production cost, large amount of waste acid and the like

Active Publication Date: 2018-12-07
JIANGSU YANGNONG CHEM GROUP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the above reaction, the alkali is generally excessive. After the solvent is recovered under negative pressure, the kettle material is relatively dry, dissolved in water, and acid is added to adjust the pH of the system to acidity, and the product 4,6-dihydroxypyrimidine is precipitated. More alkali is neutralized, and more acid is needed to neutralize, and the amount of waste acid is more, so that the production cost is higher

Method used

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  • A post-processing method for synthesizing 4,6-dihydroxypyrimidine
  • A post-processing method for synthesizing 4,6-dihydroxypyrimidine
  • A post-processing method for synthesizing 4,6-dihydroxypyrimidine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Synthesis: Add 720g (4mol) of 30% methanol solution of sodium methoxide and 112.5g (2.5mol) of formamide to a four-necked reaction flask, stir, heat up in a water bath, heat up to 50°C, and start to dropwise add 132g (1mol) of propanediol For dimethyl ester, the temperature is controlled at 50-62°C during the dropwise addition process, and it takes about 1 hour. After the dropwise addition, the temperature is raised to reflux temperature of 62-66°C, kept for 2 hours, and then lowered to room temperature.

[0026] Post-processing: the above reaction solution is subjected to negative pressure suction filtration to obtain filtrate 580g (analytical content: sodium methylate: 9.31%; formamide: 0.59%), and the concentration of negative pressure concentration to sodium methylate is about 35%. After reclaiming methanol , and the filtrate is used for recovery of alkali. At the same time, add 400g of water to dissolve the filter cake, keep the temperature of the kettle not exceed...

Embodiment 2

[0030] Synthetic process is the same as example 1.

[0031] Post-processing: the above-mentioned reaction solution is subjected to negative pressure suction filtration to obtain 600 g of filtrate (analytical content: sodium methylate: 7.86%; formamide: 0.43%), and the concentration of negative pressure concentration to sodium methylate is about 30%. After reclaiming methanol , and the filtrate is used for recovery of alkali. At the same time, add 350g of water to dissolve the filter cake, keep the temperature of the kettle not exceeding 30°C, adjust the pH to 2-3 to crystallize with 240g of industrial hydrochloric acid, keep stirring at room temperature for 1 hour, cool down to below 10°C, and filter under negative pressure. Under vacuum condition -0.09±0.01MPa, dry to obtain 4,6-dihydroxypyrimidine. The base is applied mechanically at 1.5 equivalents, that is, the recovery rate is 37.5%, and applied mechanically twice, an average of 96.9g of 4,6-dihydroxypyrimidine is obtain...

Embodiment 3

[0035] Synthetic process is the same as example 1.

[0036]Post-processing: the above-mentioned reaction solution is subjected to negative pressure suction filtration to obtain filtrate 568g (analysis content: sodium methylate: 9.51%; formamide: 0.38%), and the concentration of negative pressure concentration to sodium methylate is about 30%. After reclaiming methanol , and the filtrate is used for recovery of alkali. At the same time, add 380g of water to dissolve the filter cake, keep the temperature of the kettle not exceeding 30°C, adjust the pH to 2-3 to crystallize with 250g of industrial hydrochloric acid, keep stirring at room temperature for 1 hour, cool down to below 10°C, and filter under negative pressure. Under vacuum condition -0.09±0.01MPa, dry to obtain 4,6-dihydroxypyrimidine. The base is applied mechanically at 2 equivalents, that is, the recovery rate is calculated as 50%, and applied mechanically twice in a row to obtain an average of 95.6g of 4,6-dihydrox...

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Abstract

The invention provides a post-treatment method for 4,6-dihydroxypyrimidine synthesis, belongs to the technical field of organic chemical industry, and relates to a method for alkali recovery and application and wastewater recovery and application in a chemical industry product, particularly to a process. According to the process, formamide, dimethyl malonate and sodium methoxide are adopted as starting raw materials and cyclization is performed to prepare 4,6-dihydroxypyrimidine; after the reaction is completed, negative pressure suction filtration is performed, the filtrate is subjected to partial methanol removing, and the alkali is recovered and applied; and after the filter cake is subjected to acidification crystallization, negative pressure suction filtration is performed, the filter cake is dried to obtain the product, the mother liquor is concentrated to recover the 4,6-dihydroxypyrimidine, and the acid water is neutralized so as to be recycled while the by-product salt can be recovered so as to be comprehensively utilized. According to the present invention, after the alkali recovery and application, the acid consumption for the subsequent acidification treatment can be significantly reduced so as to substantially reduce the production cost and the three-waste amount; and the post-treatment method has characteristics of less equipment investment, three-waste treatment cost reducing, easy raw material recovery and application, and the like, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry, and relates to a method for the recovery and application of alkali and waste water in the production of chemical products, and more specifically, relates to a method starting with formamide, dimethyl malonate and sodium methoxide. Raw materials, 4,6-dihydroxypyrimidine was prepared by cyclization. After the reaction was completed, vacuum filtration was performed, and the filtrate was removed from part of the methanol, and the alkali was recovered; The product is obtained by drying, the mother liquor is concentrated to recover 4,6-dihydroxypyrimidine, the acid water is neutralized and then recycled, and the by-product salt can be recovered for comprehensive utilization. The total yield is stable at more than 88%. After alkali recovery, it can significantly reduce the amount of acid used in the subsequent acidification treatment, greatly reducing the production cost and the amount o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D239/54
CPCC07D239/54
Inventor 刘补娥朱叶峰顾峰
Owner JIANGSU YANGNONG CHEM GROUP
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