From: fernee@newton.physics.uq.oz.au (Mark Fernee)
Subject: Re: RDX
Organization: Physics Dept. The University of Queensland
Date: Tue, 15 Dec 1992 10:38:41 GMT

In article <4f_qp0200iUy81bkh=@andrew.cmu.edu>, Martin David Frankel <mf3s+@andrew.cmu.edu> writes:
|> I'm curious as to the reliability of the TBBOM 1.3 method of producing RDX.
|> 
|> To summarize:
|> 
|> 50g hexamine (hexamethylenetetramine) added slowly to 550ml nitric acid
|> over ice bath at low temperatures.
|> 
|> Drop temperature below 0 degrees C and stir for 20min at least.
|> 
|> Pour mixture over a liter of crushed ice.
|> 
|> Filter out crystals and wash in boiling distilled water to remove all traces
|> of acid.
|> 
|> Store wet until ready to use.

This is not an accepted method of producing RDX. The german SH-method 
uses a nitration temperature of between 5 and 10 deg C for a 1 hr period, 
followed by a 2 hr period at 15-20 deg C. (at no time should the reacting
mixture rise to a temperature greater than 25 deg C or an explosion may
occur). 99% HNO3 is used in this process as 8 parts acid to 1 part 
hexamine. After the nitration, the mixture is diluted in water such the
resultant temperature is maintained at between 70-75 deg C and the nitric
acid is diluted until it reaches a concentration of 50%. This process is
called the degassing phase and it is needed to decompose the unstable
nitration products which could otherwise cause an explosion. This 
proceedure precipitates the RDX which is cooled and filtered out. It
is then washed and neutralised with a sodium carbonate solution and
finally recrystalised from acetone to obtain a stable product.

A more satisfactory method is the K-method where ammonium nitrate is
added to the nitrating mixture to supply extra amino groups. This
method requires the nitration mperature to be maintained at around
80 deg C. Thus the reaction mix must be heated, rather than cooled and
there is no fear of explosoin unlike in the previous method. After a nitration
period of 1/2 hr the mixture is then cooled to 20 deg C during which the
RDX crystalises after which it is filtered and washed/neutralised and 
finally recystalised from acetone as before.

The precise details are to be found in Urbanski "the chemistry and
technology of explosives" Vol III, 1967.


|> 
|> Mix 88.3% RDX with 11.1% mineral oil and 0.6% lecithin by weight to
|> desensitize, producing composition C-1.
|> 
|> Will this procedure kill me?
|> 
|> Is C-1 stable enough to use in large (i.e. full yield of this procedure)
|> quantities without extreme danger?
|> 
|> Is the lecithin in C-1 necessary, and is the amount critical?  (My supply is
|> impure and my scale inaccurate.)
|> 
|> Is there anything else I should know to avoid premature detonation/death?
|> 
|> Is RDX spark/heat sensitive?  How about C-1?
|> 
|> Is there a preferred method of making RDX less sensitive and less dangerous
|> without losing cap-sensitivity?
|> 

RDX is commonly desensitised by mixing with montan wax. It may be
plasticised with any number of materials (including flour and water)
It is not flame or heat sensitive like a PE however it is quite sensitive
to friction, and care must be taken if the crystals are to be
ground into a fine powder. (small amounts only)

If you're sensible, using RDX should be far safer than making it.

Probably the worst part about this as any nitration, is the use of
highly concentrated nitric acid (>90%). This acid must be free of
nitric oxides and it is very nasty to handle. Don't underestimate
this. 

Mark.

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