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A new method for preparing biuret by utilizing ketazine

A technology for biuret and ketazine, which is applied in the field of preparing biuret by using ketazine, can solve the problems of environmental pollution damage, technical difficulty, long reaction time and the like, and achieves shortened reaction time, high product purity, The effect of fast heating

Inactive Publication Date: 2011-12-28
HANGZHOU HI TECH FINE CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, the method of producing biurea is mainly to condense hydrazine hydrate and urea to form biurea. Domestic hydrazine hydrate generally uses the urea method, that is, urea and sodium hypochlorite are oxidized to form hydrazine hydrate; foreign countries generally use ketazine to hydrolyze, concentrate, and refine The finished product of hydrazine hydrate generally requires a long reaction time. Although it was proposed to use acidic condensation, that is, to adjust the pH of the hydrolyzate to 1-4 with sulfuric acid, the reaction time was indeed improved, but due to the addition of a small amount of sulfuric acid, biurea formed There is a small amount of ammonium sulfate in the solution during the process. If it takes effort to recycle these small amounts of ammonium sulfate, it will be difficult and costly in the process. Therefore, manufacturers who generally use acidic condensation to produce biurea use dilute ammonium sulfate solution Direct discharge, which not only leads to environmental pollution and damage, but also a waste of resources

Method used

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  • A new method for preparing biuret by utilizing ketazine

Examples

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Effect test

Embodiment 1

[0020] Take a 1L three-necked flask, add 200mL of acetone azine, prepare 500mL of 1+1 sulfuric acid, take 160mL of sulfuric acid solution, add it dropwise to the three-necked flask, set the reaction temperature to 60°C, and weigh 173g after the addition of sulfuric acid is completed. Add urea into the three-necked flask at one time, and the temperature of the oil bath increases rapidly. When the temperature rises to 105°C, keep stirring at this temperature, and a white precipitate will appear in about ten minutes. Continue stirring for 2 hours, filter, and wash with water twice. , the filtrate was distilled with ammonia, the white precipitate was put into an oven, and baked at 50° C. for 8 hours. The measured melting point was 248° C., and the white substance was determined to be biurea, with a yield of 85%.

Embodiment 2

[0022] Take a 1L three-neck flask, add 200mL butanazine, configure 1+2 sulfuric acid 500mL, take 240mL sulfuric acid solution, add it dropwise to the three-necked flask, set the reaction temperature to 70°C, wait until the sulfuric acid is added dropwise, weigh Add 173g of urea into the three-necked flask at one time, and the temperature of the oil bath increases rapidly. When the temperature rises to 110°C, keep stirring at this temperature, and a white precipitate will appear in about five minutes. Continue stirring for 2 hours, filter, and wash with water for two hours. The second time, the filtrate was distilled with ammonia, and the white precipitate was put into an oven, and baked at 50°C for 8 hours. The melting point was 248°C. The white substance was determined to be biurea, and the yield was 86%.

Embodiment 3

[0024] Take a 1L three-necked flask, add 200mL of acetonazine, configure 500mL of 1+1 hydrochloric acid, take 260mL of hydrochloric acid solution, add it dropwise to the three-necked flask, set the reaction temperature to 80°C, and weigh 173g after the addition of hydrochloric acid is completed. Add urea into the three-necked flask at one time, and the temperature of the oil bath increases rapidly. When the temperature rises to 112°C, a white precipitate is formed. Continue to heat up to 120°C, and keep stirring at this temperature for 1 hour, filter, and wash with water twice. , the filtrate was distilled with ammonia, the white precipitate was put into an oven, baked at 50°C for 8h, and its melting point was 248°C. It was determined that the white substance was biurea, and the yield was 88%.

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Abstract

The present invention relates to a new method for preparing biurea by using ketazine. First, sulfuric acid or hydrochloric acid with a molar ratio of 1:1 to ketazine is added to ketazine to generate pure hydrazine sulfate or hydrazine hydrochloride. Then add solid urea at one time, and rapidly raise the temperature to 105-120°C to generate biurea. Advantages of the present invention are: 1, adopt ketazine and sulfuric acid (hydrochloric acid) to generate hydrazine sulfate (hydrazine hydrochloride), avoid the hydrolysis and concentration process that ketazine is longer in the traditional technique, the method reacts rapidly, and the hydrazine sulfate obtained The purity is high, and the yield of biurea is high. 2. Using hydrazine sulfate and urea to react, the heating speed is fast, the product purity is high, and the yield of the obtained biuret is more than 85%. 3. The by-product ammonium salt can be recycled through the quicklime ammonia distillation process and returned to the ketazine synthesis device to realize the full recycling of materials.

Description

technical field [0001] The invention relates to a method for producing biurea, in particular to a new method for preparing biurea by using ketazine. Background technique [0002] The English name of biurea is biurea, the chemical name is hydrazinedicarboxamide, the molecular formula is C2H6N4O2, and the chemical formula is H2NCONH-NHCON2H. It is mainly used in the production of ADC foaming agent (azodicarbonamide), and can also be used in airstrips, high-grade roads, anti-skid gears, and fire-proof and anti-melt of high-grade cables. [0003] At present, the method of producing biurea is mainly to condense hydrazine hydrate and urea to form biurea. Domestic hydrazine hydrate generally uses the urea method, that is, urea and sodium hypochlorite are oxidized to form hydrazine hydrate; foreign countries generally use ketazine to hydrolyze, concentrate, and refine The finished product of hydrazine hydrate generally requires a long reaction time. Although it was proposed to use ...

Claims

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Application Information

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IPC IPC(8): C07C281/06
Inventor 董梅陈海贤王青红汪永红
Owner HANGZHOU HI TECH FINE CHEM
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