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Not a duplicate of Hydrazine synthesis - I know what hydrazine is and am not going near it voluntarily!

Looked at this resource on the Internet which cites three major commercial-scale processes:

  • $\ce{H_2O_2}$ process (in use at Arkema and Mitsubishi Gas Chemical, developed by Produits Chimiques Ugine Kuhlmann and patented in 1976)
  • Bayer process (at the eponymous company)
  • Urea process

What processes do other major large-scale producers use and what are the driving forces behind adoption of a particular hydrazine synthesis? I can guess that Chinese producers may use the urea process, but I'm not sure.

Background: am a Space Exploration.SE regular and am interested in learning more about worldwide production of hypergolic propellants.

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  • $\begingroup$ I think that Chemistry of the Elements by Greenwood and Earnshaw might have something to say about this topic. If nobody else has checked it within the next few hours I'll pop out to my library and report back to you. $\endgroup$ – orthocresol Jun 2 '15 at 16:51
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The Kirk-Othmer Encyclopedia of Chemical Technology reports that: "About 60% is made by the [Bayer] hypochlorite–ketazine process, 25% by the peroxide–ketazine route, and the remainder by the Raschig and urea processes." Here is a link to the original article, if you can access it (e.g. at a university library): Hydrazine and Its Derivatives, by Eugene F. Rothgery. The data cited dates back to 2004, so it may have changed somewhat, but probably not too much.

Consider this also: the above makes hydrazine hydrate. Propellant-grade hydrazine must be anhydrous, so there is an extra step in which water is removed from the hydrate, typically by azeotropic distillation with aniline.

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    $\begingroup$ Thanks for the Kirk-Othmer tip, have looked the data up. Could you please explain why these processes were chosen? $\endgroup$ – Deer Hunter Jun 2 '15 at 17:18
  • $\begingroup$ @DeerHunter I'm afraid that I don't really have any good insight as to the choice of these methods. $\endgroup$ – MarcoB Jun 3 '15 at 4:28
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I would hazard a guess that the economies of scale of where the process is located comes into play. Arkema may make bulk $\ce{H2O2}$ at industrial concentration so can just feed it in without transport and hence dilution isn't required . Bayer (or a neighbour) may operate a chloralkali process on site, so use that. Everything will come down to the input costs.

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