CN103044290A - Method for increasing reaction speed in preparing biurea by condensing with weak base method - Google Patents
Method for increasing reaction speed in preparing biurea by condensing with weak base method Download PDFInfo
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- CN103044290A CN103044290A CN2013100072043A CN201310007204A CN103044290A CN 103044290 A CN103044290 A CN 103044290A CN 2013100072043 A CN2013100072043 A CN 2013100072043A CN 201310007204 A CN201310007204 A CN 201310007204A CN 103044290 A CN103044290 A CN 103044290A
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Abstract
The invention provides a method for increasing a reaction speed in preparing biurea by condensing with a weak base method. The method comprises the following steps that A, a salt hydrazine-free solution is prepared, with net content of 2-50%; B, carbamide is dissolved by the salt hydrazine-free solution; a mass ratio of hydrazine hydrate to carbamide is 1:(2.4-5); C, prepared condensation reaction liquid is added to a container with stirring and backflow; strong acid is added according to that a mole ratio of hydrazine hydrate to strong acid is 1:(0.1-2), heated, and subjected to boiling reaction; and D, the concentration of hydrazine hydrate is reduced below 1g/l; filtration, separation and washing are conducted after the reaction; and biurea is obtained. The method has the benefits that the quality of biurea is ensured on the condition that no other inorganic salt is introduced; in addition, as strong acid is added, the speed of condensation reaction of weak base is increased greatly; the production efficiency is improved; and the method has higher economic benefits.
Description
Technical field
The present invention relates to the hydrazo-dicarbonamide field, be specifically related to a kind of method that the condensation of weak base method prepares the hydrazo-dicarbonamide speed of response that improves.
Background technology
Hydrazo-dicarbonamide, chemical name is the hydrazo diformamide, is to produce the necessary intermediate of azodicarbonamide foaming agent, can be used for also that the back-fire relief of anti-skidding and senior cable of airstrip is anti-to be melted etc.
The preparation method of hydrazo-dicarbonamide carries out the condensation reaction preparation by hydrazine hydrate under weak acid or weak basic condition.Under the weak acid reaction conditions, speed of response is fast, but contains a large amount of ammonium salts or the inorganic salts such as sodium-chlor of front system in the reaction product, has affected the quality of hydrazo-dicarbonamide.Under weak basic condition, reaction system is simple, and reaction product is hydrazo-dicarbonamide and ammonia, and filtration washing is easy, but speed of response is generally slower.Under the concentration of lower hydrazine hydrate, if acid-respons generally in 6h, weak base reacts generally about 12h.
On the basis that guarantees the hydrazo-dicarbonamide quality product, in order to improve the speed of response of weak base method condensation hydrazo-dicarbonamide, in the reaction system of weak base method condensation hydrazo-dicarbonamide, add a small amount of strong acid, namely can guarantee the quality of product, simultaneously can also improve speed of response, reduce production costs.
Summary of the invention
The object of the invention is to overcome the deficiency that prior art exists, and provide a kind of method that the condensation of weak base method prepares the hydrazo-dicarbonamide speed of response that improves, carrying out in the condensation reaction with salt-free hydrazine and urea, add a small amount of strong acid in salt-free hydrazine or reaction system, the speed of response that can make the anacidity condensation generate hydrazo-dicarbonamide improves more than 30%.
The objective of the invention is to finish by following technical solution.The condensation of this raising weak base method prepares the method for hydrazo-dicarbonamide speed of response, and the method comprises following step:
A. dispose salt-free hydrazine solution, net content is 2 ~ 50%;
B. use salt-free hydrazine solution dissolved urea, hydrazine hydrate is 1:2.4 ~ 5 with the urea quality ratio;
C. join with in the container that stirs, refluxes preparing condensation reaction solution, add strong acid, the strong acid add-on is 1:0.1 ~ 2 by the mol ratio of hydrazine hydrate and strong acid, and heating makes its boiling reaction;
D. hydrazine hydrate concentration is reduced to below the 1g/l, and after reaction finished, the filtering separation washing obtained hydrazo-dicarbonamide.
Described strong acid can add in salt-free hydrazine, or adds in the reaction solution behind dissolved urea, or adds in heating afterreaction process, can be any concentration.
Described strong acid is one or more of sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, oxalic acid, Lewis acid and solid strong acid.
Beneficial effect of the present invention is: compare with present weak base method hydrazo-dicarbonamide, under the condition of the inorganic salt of not introducing other, guaranteed the quality of hydrazo-dicarbonamide.Simultaneously, by the adding of strong acid, raising by a relatively large margin the speed of weak base condensation reaction, improved production efficiency, have higher economic benefit.
Embodiment
The present invention is further elaborated below by embodiment, and embodiment will help to understand better the present invention, but the present invention is not limited only to following embodiment.
Embodiment 1
Analytical pure 80% hydrazine hydrate is configured to 20% hydrazine hydrate 500g, again to wherein adding urea 300g, after the dissolving, is put in the four-hole boiling flask with stirring, reflux of 1000ml fully, be heated to boiling.The ammonia that reaction generates absorbs with acid, and being reacted to hydrazine hydrate concentration is 0.87g/l, and reaction finishes, and filtration washing obtains hydrazo-dicarbonamide 223.5g.Reaction times 12.8h.
Embodiment 2
Analytical pure 80% hydrazine hydrate is configured to 20% hydrazine hydrate 500g, to the hydrochloric acid 180ml that wherein adds 37.5%, again to wherein adding urea 300g, after the dissolving, is put in the four-hole boiling flask with stirring, reflux of 1000ml fully, be heated to boiling.The ammonia that reaction generates absorbs with acid, and being reacted to hydrazine hydrate concentration is 0.68g/l, and reaction finishes, and filtration washing obtains hydrazo-dicarbonamide 220.7g.Reaction times 9.5h.
Embodiment 3
Analytical pure 80% hydrazine hydrate is configured to 20% hydrazine hydrate 500g, again to wherein adding urea 300g, after the dissolving, adds 98% vitriol oil 85ml fully, be put in the four-hole boiling flask with stirring, reflux of 1000ml, be heated to boiling.The ammonia that reaction generates absorbs with acid, and being reacted to hydrazine hydrate concentration is 0.55g/l, and reaction finishes, and filtration washing obtains hydrazo-dicarbonamide 221.8g.Reaction times 8.5h.
At last, should be pointed out that above example only is the more representational example of the present invention.Obviously, technical scheme of the present invention is not limited to above-mentioned example, and many distortion can also be arranged, and all distortion that those of ordinary skill in the art can directly derive or associate from content disclosed by the invention all should be thought protection scope of the present invention.
Claims (3)
1. one kind is improved the method that the condensation of weak base method prepares the hydrazo-dicarbonamide speed of response, and it is characterized in that: the method comprises following step:
A. dispose salt-free hydrazine solution, net content is 2 ~ 50%;
B. use salt-free hydrazine solution dissolved urea, hydrazine hydrate is 1:2.4 ~ 5 with the urea quality ratio;
C. join with in the container that stirs, refluxes preparing condensation reaction solution, add strong acid, the strong acid add-on is 1:0.1 ~ 2 by the mol ratio of hydrazine hydrate and strong acid, and heating makes its boiling reaction;
D. hydrazine hydrate concentration is reduced to below the 1g/l, and after reaction finished, the filtering separation washing obtained hydrazo-dicarbonamide.
2. raising weak base method according to claim 1 condensation prepares the method for hydrazo-dicarbonamide speed of response, and it is characterized in that: described strong acid adds in salt-free hydrazine, or adds in the reaction solution behind dissolved urea, or adds in heating afterreaction process.
3. raising weak base method according to claim 1 condensation prepares the method for hydrazo-dicarbonamide speed of response, it is characterized in that: described strong acid is one or more of sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, oxalic acid, Lewis acid and solid strong acid.
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| CN2013100072043A CN103044290A (en) | 2013-01-08 | 2013-01-08 | Method for increasing reaction speed in preparing biurea by condensing with weak base method |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA707795A (en) * | 1965-04-13 | Mehr Louis | Manufacture of biurea | |
| US3227753A (en) * | 1962-02-19 | 1966-01-04 | Wallace & Tiernan Inc | Manufacture of biurea |
| CN1803899A (en) * | 2005-12-27 | 2006-07-19 | 薛式华 | Method for preparing AC blowing agent |
| CN1986524A (en) * | 2006-12-21 | 2007-06-27 | 巨化集团技术中心 | Preparing process for biurea |
| CN101219973A (en) * | 2008-01-22 | 2008-07-16 | 浙江海虹控股集团有限公司 | Process for producing biurea |
| CN101838224A (en) * | 2009-03-19 | 2010-09-22 | 华东理工大学 | Method for reducing grain size of AC foaming agent |
| WO2012025038A1 (en) * | 2010-08-27 | 2012-03-01 | 浙江工程设计有限公司 | Continuous manufacturing method and apparatus for synthesized hydazo dicarbonamide |
-
2013
- 2013-01-08 CN CN2013100072043A patent/CN103044290A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA707795A (en) * | 1965-04-13 | Mehr Louis | Manufacture of biurea | |
| US3227753A (en) * | 1962-02-19 | 1966-01-04 | Wallace & Tiernan Inc | Manufacture of biurea |
| CN1803899A (en) * | 2005-12-27 | 2006-07-19 | 薛式华 | Method for preparing AC blowing agent |
| CN1986524A (en) * | 2006-12-21 | 2007-06-27 | 巨化集团技术中心 | Preparing process for biurea |
| CN101219973A (en) * | 2008-01-22 | 2008-07-16 | 浙江海虹控股集团有限公司 | Process for producing biurea |
| CN101838224A (en) * | 2009-03-19 | 2010-09-22 | 华东理工大学 | Method for reducing grain size of AC foaming agent |
| WO2012025038A1 (en) * | 2010-08-27 | 2012-03-01 | 浙江工程设计有限公司 | Continuous manufacturing method and apparatus for synthesized hydazo dicarbonamide |
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Application publication date: 20130417 |