To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
Languages
Recent
Show all languages
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

Peroxide process

From Wikipedia, the free encyclopedia

The peroxide process is a method for the industrial production of hydrazine.

In this process hydrogen peroxide is used as an oxidant instead of sodium hypochlorite, which is traditionally used to generate hydrazine. The main advantage of the peroxide process to hydrazine relative to the traditional Olin Raschig process is that it does not coproduce salt. In this respect, the peroxide process is an example of green chemistry. Since many millions of kilograms of hydrazine are produced annually, this method is of both commercial and environmental significance.[1]

YouTube Encyclopedic

  • 1/3
    Views:
    616
    11 141
    163 337
  • Introduction to Servicing the Sterrad® NX™ Hydrogen Peroxide Sterilization System
  • How to clean air stones under 1$! Fastest way to desinfect and clean your air stones.
  • How Paper is made from sugar cane | A Don Morris video.

Transcription

Production

Ketazine formation

In the usual implementation, hydrogen peroxide is used together with acetamide. This mixture does not react with ammonia directly but does so in the presence of methyl ethyl ketone to give the oxaziridine.

Balanced equations for the individual steps are as follows. Imine formation through condensation:

Me(Et)C=O + NH3 → Me(Et)C=NH + H2O

Oxidation of the imine to the oxaziridine:

Me(Et)C=NH + H2O2 → Me(Et)CONH + H2O

Condensation of the oxaziridine with a second molecule of ammonia to give the hydrazone:

Me(Et)CONH + NH3 → Me(Et)C=NNH2 + H2O

The hydrazone then condenses with a second equivalent of ketone to give the ketazine:

Me(Et)C=O + Me(Et)C=NNH2 → Me(Et)C=NN=C(Et)Me + H2O

Typical process conditions are 50 °C and atmospheric pressure, with a feed mix of H2O2:ketone:NH3 in a molar ratio of about 1:2:4.[2] Methyl ethyl ketone is advantageous to acetone because the resulting ketazine is immiscible in the reaction mixture and can be separated by decantation.[2] A similar process based on benzophenone has also been described.[3]

Ketazine to hydrazine

The final stage involves hydrolysis of the purified ketazine:

Me(Et)C=NN=C(Et)Me + 2 H2O → 2 Me(Et)C=O + N2H4

The hydrolysis of the azine is acid-catalyzed, hence the need to isolate the azine from the initial ammonia-containing reaction mixture. It is also endothermic,[4] and so requires an increase in temperature (and pressure) to shift the equilibrium in favour of the desired products: ketone (which is recycled) and hydrazine hydrate.[5] The reaction is carried out by simple distillation of the azeotrope: typical conditions are a pressure of 8 bar and temperatures of 130 °C at the top of the column and 179 °C at the bottom of the column. The hydrazine hydrate (30–45% aqueous solution) is run off from the base of the column, while the methyl ethyl ketone is distilled off from the top of the column and recycled.[5]

History

The peroxide process, also called the Pechiney–Ugine–Kuhlmann process, was developed in the early 1970s by Produits Chimiques Ugine Kuhlmann.[6][5] Originally the process used acetone instead of methyl ethyl ketone.[6] Methyl ethyl ketone is advantageous because the resulting ketazine is immiscible in the reaction mixture and can be separated by decantation.[2][7] The world's largest hydrazine hydrate plant is in Lannemezan in France, producing 17,000 tonnes of hydrazine products per year.[8]

Bayer ketazine process

Before invention of the peroxide process, the Bayer ketazine process had been commercialized. In the Bayer process, the oxidation of ammonia by sodium hypochlorite is conducted in the presence of acetone. The process generates the ketazine but also sodium chloride:[1]

2 Me2CO + 2 NH3 + NaOCl → Me2C=NN=CMe2 + 3 H2O + NaCl
Me2C=NN=CMe2 + 2 H2O → N2H4 + 2 Me2CO

References

  1. ^ a b Jean-Pierre Schirmann, Paul Bourdauducq "Hydrazine" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a13_177.
  2. ^ a b c Maxwell, Gary R. (2004), Synthetic nitrogen products: a practical guide to the products and processes, Springer, pp. 342–44, ISBN 0-306-48225-8.
  3. ^ Hayashi, Hiromu; Kainoh, Akihiko; Katayama, Masayoshi; Kawasaki, Kengo; Okazaki, Tatsuya (1976), "Hydrazine Production from Ammonia via Azine", Ind. Eng. Chem. Prod. Res. Dev., 15 (4): 299–303, doi:10.1021/i360060a016.
  4. ^ Gilbert, E. C. (1929), "Studies on Hydrazine. The Hydrolysis of Dimethylketazine and the Equilibrium between Hydrazine and Acetone", J. Am. Chem. Soc., 51 (11): 3394–3409, doi:10.1021/ja01386a032.
  5. ^ a b c US 4724133, Schirmann, Jean-Pierre; Combroux, Jean & Delavarenne, Serge Y., "Preparation of a concentrated aqueous solution of hydrazine hydrate", published 1988-02-09, assigned to Atochem .
  6. ^ a b US 3972878, Schirmann, Jean-Pierre; Combroux, Jean & Delavarenne, Serge Yvon, "Method for preparing azines and hydrazones", published 1976-08-03, assigned to Produits Chimiques Ugine Kuhlmann . US 3978049, Schirmann, Jean-Pierre; Tellier, Pierre & Mathais, Henri et al., "Process for the preparation of hydrazine compounds", issued 1976-08-31, assigned to Produits Chimiques Ugine Kuhlmann .
  7. ^ Cotton, F. Albert; Wilkinson, Geoffrey (1988), Advanced Inorganic Chemistry (5th ed.), New York: Wiley-Interscience, pp. 317–18, ISBN 0-471-84997-9.
  8. ^ Site industriel de Lannemezan (PDF), Arkema, archived from the original (PDF) on 2011-09-04, retrieved 2010-07-02.


This page was last edited on 22 July 2023, at 12:31
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.