[Enthalpy]

I consider dimethyldiazetidines as good candidates as rocket fuels, to replace toxic monomethyl- and dimethyl- hydrazine.

First, you may see there how they look like:
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2372#p28464
not really surprising [1,3-trans-dimethyl-1,3-diazetidine macht Kinder froh].

Not very common, but the 1,2- has at least one supplier and a Cas number.

-----

1,2-etc was checked as a rocket fuel in a 1968 report. It has usable melting and boiling temperatures, a good density:
http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=AD0093924 on page 28 paragraph 11 (Pdf 39/123)

But this report estimates a disappointing heat of formation and deduces low performance, there:
Table XXXIX page 80 (Pdf 91/123)
As opposed, Am1 estimates a nice heat of formation that would give excellent performance.
The discrepancy is bigger than usual: 100kJ/mol for just C₄H₈N₂.

I tried to decide between both values by making hand estimates based on similar molecules, there:
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2372#p30178 at the dotted list.
Could you please check the arguments, or even the figures?

Such a move would be useful. MMH and UDMH are carcinogens, satellites use tons of them, some rockets hundreds of tons. Agencies and companies want to get rid of hydrazines, but this is difficult; maybe dimethyldiazetidine (or a relative) improves safety and even performance.

-----

I imagine 1,2-etc-diazetidine may be unhealthy, just because of its N-N like in hydrazines and nitramines.
With just 1s performance less (still 3s over MMH!), I hence prefer 1,3-etc-diazetidine.
Your opinion please?

-----

Would these molecules be difficult to produce in ton amounts (satellites) or hundreds of tons (launchers)?
The cited report (link to Pdf above) gives one method for 1,2-etc on page 28 paragraph 11 (Pdf 39/123), none for the 1,3-etc I'd prefer. Preferred variants would probably have methyl bumps or an alkane tail to improve the liquid range.
Your opinion please?

Thank you!

[Enthalpy]

These variants shall be more benign since their boiling point is higher:
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2372#p30243
and they still expose the nitrogens to the desires of N₂O₄.

Your opinion, including about dimethyldiazetidine?

It would be useful! Getting rid of monomethyl- and dimethyl- hydrazine is a hot topic in rocketry. Alternatives have been rejected because of lower performance. But Dimethyldiazetidine is even more efficient than MMH if I estimated it properly, so it would be highly welcome!