Sciencemadness Discussion Board

Nitromethane Sensitizers and Det Cord

holmes1880 - 6-6-2011 at 19:23

Has anyone read or seen a documented reference of hexamine, aka fuel starter tablets, being used to sensitize NM to become sensitive to detonation?

I found it sort of "referenced" in this document, but I am not sure whether it is the hexamine I have in mind- after all, people say it's hard to dissolve in NM. According to the paper, it can det,

Since ethelenydiamine (EDA) or morpholine is so problematic to come by, hexamine would be a desired substitute for sensitizing NM to be useful in small CD amounts.

[Edited on 7-6-2011 by holmes1880]

franklyn - 7-6-2011 at 17:10

Operational circumstances are succinctly stated on page 10 of the cited reference.
12 mm is critical diameter when strongly boosted. The table on page 9 lists one
Hexamine shot , less than 3 % by volume , yielding 6640 m/s. Not considered is
the effect of voids ( bubbles ) to sensitize NM.
Having a deficit of oxygen , blending with an oxidizer as in the case with Kinepak ,
would seem more fruitful in improving performance and reducing critical diameter;
although the poor character of ammonium nitrate actually degrades v.o.d. in this
particular case. The acid character of nitromethane may solvate sodium nitrite to
form nitrous acid and the nitronate sodium salt, rendering it sensitive. Blending with
dinitrogen tetroxide should give very good results. Hi test hydrogen peroxide also.


[Edited on 8-6-2011 by franklyn]

holmes1880 - 7-6-2011 at 17:20

So you're seeing them use hexamine too. That will be my 1st test.
Yes, blending it with AN could help to sensitize, but I need it to maintain its low viscosity so as to be injected in a 6-10mm vinyl tube with a syringe. If it has a gel consistency and/or have grains - it will become problematic.

PHILOU Zrealone - 8-6-2011 at 02:41

Hexamine (CH2)6N4, is a discrete and stable form of NH3 and CH2=O.
It is possible that:
1°) Hexamine is mildly basic and as such favourise somehow the formation of some nitronic variant of nitromethane rendering it more sensitive.
(CH2)6N4 + CH3-NO2 <==> (CH2)6N4H(+) + CH2=N(=O)(-O-)(-)
It must be very discrete but if it happens a little yellow/orange colourization should occure (maybe only noticeable via spectrophotometry)

2°)Hexamine hydrolyses/decompose a bit into its constitutive elements NH3 and CH2=O:
-The NH3 is more basic than hexamine and might form the nitronate salt and sensitise NM, but also microbubbles also sensitising the stuff.
-The CH2=O might react with nitromethane in basic media to form some
HO-CH2-CH2-NO2 and CH2=CH-NO2
so contributing to the decomposition and shifting of hexamine into formaldehyde scavenging and amonia liberation.

Again this must be visible via color change or spectrophotometry.

Amonia or hydrazine and CH3-NO2 turn very fast yellow-orange-brown...but concentrations I have used are high (>25%) this case from hexamine it could be less than 1% of 3% (= 0.03%)

holmes1880 - 8-6-2011 at 05:29

Thank you for that. Indeed, I mixed a small quantity of NM with a 5% cleaning ammonia and it gained yellow tinge, as well as created some oily yellow bubbles within it. It failed to detonate, however, since I was only using a #8 cap and CD was 6.5mm in the tube.

My hope is that hexamine is approximately as effective as EDA or morpholine, that was referenced within the paper to be able to sensitize NM to 6mm CD. I think it's very lazy of those researchers to have tested 12mm diameter, but then say: "well, the critical diameter is somewhere below 12mm". Now I have to do the leg work.

pjig - 8-6-2011 at 07:17

I think that one prob is the % of the ammonia. If Im correct the patents out there use a 20% + strength ammonia. Household ammonia may work, but I have never herd of it being used in that low of strength as a sensitizer.

holmes1880 - 8-6-2011 at 09:06

Yep. I frankly couldn't determine even the % the ammonia had- could have been 10% or 30%- no clue.