Sciencemadness Discussion Board

polynitrogen salts

Solomon - 3-1-2014 at 23:43

Is it possible to calculate the detonation velocity of a polynitrogen enegetic salt using conventional formulas for detonation velocity?

DubaiAmateurRocketry - 4-1-2014 at 01:41

if you have enough information of the compound then maybe yes. The closest to poly nitrogen salt right now ever synthesized to my knowledge is the compound [N5]+ [B(N3)4]- with empirical formula of BN17.

Solomon - 4-1-2014 at 02:15

there have been 13 polynitrogen salts synthesized. These are described in a breif paper by Karl O. Christie. He sites another paper that gives far more detailed information regarding the synthesis and charachterization in his refrences. Thank you.

[Edited on 1-4-2014 by Solomon]

Dany - 4-1-2014 at 04:31

Semi-empirical formula of Kamlet and Jacobs or the formula of Keshavarz or other commonly used relationships are calibrated to very known explosive, explosive that bear "normal" explosophoric group (e.g., nitro, nitrato, nitramine...). so small errors is expected when applying these formulas to molecule similar to those used for calibration. However, one should be very cautious when using these formula to explosive molecule that deviate significantly in term of chemical composition and structure from those used for calibration. large deviation may occur when applying to homoleptic polynitrogen energetic materials. In the absence of experimental detonation velocity for polynitrogen compounds (due to their sensitivity and small quantity synthesized) doubt will still exist on the validity of these simple relationships. On the other hand, studies realized by Dr. Charles MADER (Los Alamos National Laboratory) on boron containing explosive like mixture of ethyl decaborane/tetranitromethane proved that the FORTRAN BKW (a thermochemical code used by MADER in the 60') is reliable for the calculation of detonation performance of explosive containing boron. This led to the famous conclusion that boron in explosive mixture DO NOT improve detonation performance over normal C-H-N-O explosive. The reason is that when boron react in detonation it form large molecular weight product (e.g., B2O3, BF3). These large molecular species have high thermal energy and low intermolecular potential energy, this mean that boron in explosive generate high temperature but low detonation performance, and the energy is only available at high expansion of detonation products along the isentrope.

for full list of article and work of Dr. MADER see:

http://www.mccohi.com/vita.pdf

below i attached a previously classified study for Dr. MADER wich deal with boron explosive detonation performance

Dany.

[Edited on 4-1-2014 by Dany]

Attachment: Performance of boron explosive.pdf (1.6MB)
This file has been downloaded 693 times

DubaiAmateurRocketry - 4-1-2014 at 05:08

Quote: Originally posted by Solomon  
there have been 13 polynitrogen salts synthesized. These are described in a breif paper by Karl O. Christie. He sites another paper that gives far more detailed information regarding the synthesis and charachterization in his refrences. Thank you.

[Edited on 1-4-2014 by Solomon]


Yes he have synthesized many salts with the cations [C(N3)3]+ and [N5]+ with extremely nitrogenous anions like [P(N3)6]-

However it seems he is more like the chemistry side rather than energetic materials. He did not give important information such as density. And did not post much calculations related to their performance of detonation.

However he did synthesize a lot of these salts, PN23 was synthesized on 0.5 grams scale !! That is a lot. However it exploded in a test tube later. the result of the explosion is available in his paper. The sensitivity is probably something similar to nitrogen triiodide

http://onlinelibrary.wiley.com/doi/10.1002/ange.200454242/ab...

He also synthesized [C(N3)3]+ [N(NO2)2]-

Attachment: [C(N3)3]+ cation and its salts (174kB)
This file has been downloaded 688 times

[Edited on 4-1-2014 by DubaiAmateurRocketry]

Solomon - 4-1-2014 at 14:11

I know he synthesized the N5SbF6 salt on the 5 gram scale, but I had also been currious why things like detonation velocity, pressure, density, etc... were not listed.

Solomon - 4-1-2014 at 16:30

Am I correct in assuming that the equations in http://www.wydawnictwa.ipo.waw.pl/cejem/Cejem-8-4-2011/Smirn... should work for polynitrogen salts (detonation velocity and pressure on p. 236)?

DubaiAmateurRocketry - 6-1-2014 at 10:13

The paper you posted have under-calculated value for every compound in table 3. compounds 6-10 are extremely powerful that can beat ONC by few thousand ms however the papar circles around the 10 kms.