Preparation method of 6-amino-1,3-dimethyluracil

A technology of dimethyl uracil and dimethyl urea, which is applied in the field of preparation of 6-amino-1,3-dimethyl uracil, can solve the problems of poor long-term burning resistance, lead salt hazard, zinc burning, etc.

Inactive Publication Date: 2018-01-05
XINHUA PHARM (SHOUGUANG) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Defects and deficiencies in the prior art: the lead salt composite stabilizer has good thermal stability and has been widely used, but the lead salt has double hazards to the human body and the environment. The development and research of PVC stabilizers tend to be non-toxic and pollution-free. Cd, Research...

Method used

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Examples

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Effect test

preparation example Construction

[0023] The preparation method of described 6-amino-1,3-dimethyluracil specifically comprises steps:

[0024] 1) Weigh 600±20kg of chloroacetic acid, add water to dissolve, then add sodium carbonate solution to neutralize, control neutralization temperature ≤ 65°C, pH 7.0~10.0;

[0025] 2) Add 280-320kg of sodium cyanide, control the bump temperature of the cyanation reaction to 70-130°C, and rapidly cool down to below 30°C;

[0026] 3) Add 300-340 kg of pure hydrochloric acid within 1 hour, and control the temperature to not exceed 60°C for acidification. After acidification, raise the temperature and reduce pressure to pump water, keep the vacuum ≥ 0.085MPa, and the pumping temperature does not exceed 95°C. The water content per g / ml unit at the end point should not exceed 4%;

[0027] 4) Cool down to a liquid temperature of 25-55°C, add a calculated amount of dimethylurea, add acetic anhydride, raise the temperature to 70-120°C, and keep the reaction for 55-60 minutes to ge...

Embodiment 1

[0036] A preparation method of 6-amino-1,3-dimethyluracil, the method is that cyanoacetic acid and 1,3-dimethylurea are condensed under the action of acetic anhydride to obtain dimethylcyanoacetylurea, Afterwards, dimethyl cyanoacetylurea is obtained by cyclization reaction under alkaline conditions.

[0037] The cyanoacetic acid is obtained through neutralization and cyanation of chloroacetic acid.

[0038] The preparation method of described 6-amino-1,3-dimethyluracil specifically comprises steps:

[0039] 1) Weigh 600±20kg of chloroacetic acid, add water to dissolve, then add sodium carbonate solution to neutralize, control the neutralization temperature at 65°C, and pH 7.0;

[0040] 2) Add 280-kg of sodium cyanide, control the bump temperature of the cyanation reaction to 130°C, and rapidly cool down to 30°C;

[0041] 3) Add a pure amount of hydrochloric acid of 300-kg within 1 hour, and control the temperature at 60°C for acidification. The unit of ml contains 4% water...

Embodiment 2

[0050] A preparation method of 6-amino-1,3-dimethyluracil, the method is that cyanoacetic acid and 1,3-dimethylurea are condensed under the action of acetic anhydride to obtain dimethylcyanoacetylurea, Afterwards, dimethyl cyanoacetylurea is obtained by cyclization reaction under alkaline conditions.

[0051] The cyanoacetic acid is obtained through neutralization and cyanation of chloroacetic acid.

[0052] The preparation method of described 6-amino-1,3-dimethyluracil specifically comprises steps:

[0053] 1) Weigh 600±20kg of chloroacetic acid, add water to dissolve, then add sodium carbonate solution to neutralize, control the neutralization temperature at 60°C, and pH 8.0;

[0054] 2) Add ~300kg of sodium cyanide, control the bump temperature of the cyanation reaction to 100°C, and rapidly cool down to 28°C;

[0055] 3) Add the pure amount of hydrochloric acid ~ 320kg within 1h, control the temperature at 58°C for acidification, after the acidification is completed, raise...

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PUM

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Abstract

The invention discloses a preparation method of 6-amino-1,3-dimethyluracil. According to the preparation method, cyanoacetic acid and 1,3-dimethylurea undergo condensation under the action of acetic anhydride so as to obtain 2-cyano-N-methyl-N-[(methylamino)carbonyl]acetamide; and then 2-cyano-N-methyl-N-[(methylamino)carbonyl]acetamide undergoes a cyclization reaction under an alkaline conditionso as to obtain 6-amino-1,3-dimethyluracil. The 6-amino-1,3-dimethyluracil has a good system stabilizing effect when used as a main component of a PVC stabilizer along with zinc stearate, and has a better synergistic effect than a commonly-used counterpart in the industry at present. The 6-amino-1,3-dimethyluracil can absorb HCl and also can replace unstable chlorine atoms. On the other hand, the6-amino-1,3-dimethyluracil also can react with ZnCl2 to generate a metal complex and inactivate ZnCl2. Thus, long-term stability of a PVC sample is greatly enhanced.

Description

technical field [0001] The invention relates to the technical field of chemical engineering, in particular to a preparation method of 6-amino-1,3-dimethyluracil. Background technique [0002] Due to the poor thermal stability of polyvinyl chloride, corresponding stabilizers must be added to repair the defects of the PVC chain, and at the same time absorb the HCL produced by PVC dechlorination in time. To achieve good stability of polyvinyl chloride, it is often necessary to use multiple PVC heat stabilizers at the same time. [0003] Defects and deficiencies in the prior art: the lead salt composite stabilizer has good thermal stability and has been widely used, but the lead salt has double hazards to the human body and the environment. The development and research of PVC stabilizers tend to be non-toxic and pollution-free. Cd, Research on the development of alternatives to Pb stabilizers is very active. [0004] Calcium stearate and zinc stearate are cheap, non-toxic heat...

Claims

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Application Information

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IPC IPC(8): C07D239/545C08K5/3462C08L27/06
Inventor 杜德平王超学靳延辉刘强王丽曼
Owner XINHUA PHARM (SHOUGUANG) CO LTD
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