Sciencemadness Discussion Board

Melamine dinitrate

simply RED - 29-12-2013 at 08:06

From patent:
http://www.google.com.br/patents/US8226782

MDN is a thermally stable salt of melamine (2,4,6-triamino-1,3,5-triazine) and nitric acid. The synthesis of MDN has been reported by Friedemann et al. (New Trends Res. Energetic Materials. Part II, Pardubice, Czech Republic, 876-882, Apr. 25-27, 2007). Briefly, MDN may be prepared by slowly mixing warm nitric acid with melamine solution (100° C.). After cooling to room temperature, MDN crystals may be precipitated and obtained by filtration. Using the method of Rothstein and Peterson (Propellants, Explosives, and Pyrotechnics, 4:56, 1979), the detonation velocity of MDN is estimated to be 8.91 km/sec. The thermal stability for MDN may be tested using an oven at a set temperature for a period of time. For example, MDN was found to be stable at 137 ° C. for 48 hours without detectable decomposition. Therefore, MDN should be stable at a temperature about 200 ° C. (the temperature found in wellbore) for several hours, making it suitable for use in wellbore applications.

As an explosive, MDN appears to exhibit properties (such as densities, detonation velocities, and thermal stability) similar to other explosives, including RDX and HMX. However, the advantages of using MDN include the ease and the low cost of manufacturing MDN, as compared with that of RDX or HMX. Therefore, MDN or its analogues may be low cost alternatives to RDX or HMX with good performance and good oxygen balance.

Is this really true? Do you have more info on the topic?

Dany - 29-12-2013 at 08:29

and your interested in this compound since 2005?

http://parazite.nn.fi/roguesci/index.php/t-4256.html

Dany.

Dany - 29-12-2013 at 09:06

simply RED,

in his PhD thesis, Micheal GOEBEL synthesized MDN and other interesting melaminium energetic derivatives. the data for MDN taken from GOEBEL thesis (see table 2.4 page 94):

Density: 1.852 g/cm3
Heat of formation: -149.8 kcal/mol
Pcj= 236 kbar
Dcj= 7723 m/s
Tdecomposition= 330°C

My calculation with FORTRAN BKW yield Dcj= 7784 m/s and Pcj= 270 kbar (using TNT parameter set).

the preparation of MDN (taken from GOEBEL) is as follow:

"Nitric acid (7 mL, 0.1 mol, 65 %) was added drop wise to a hot aqueous solution (95 °C) of melamine (0.226 mg, 1 mmol in 5 mL H2O). Subsequent cooling of the reaction mixture to room temperature afforded precipitation of colorless crystalline product in pure form containing single crystals suitable for X-ray diffraction analysis"

the thesis of Micheal GOEBEL can be found following this link

http://edoc.ub.uni-muenchen.de/12420/1/goebel_michael.pdf

Dany.


[Edited on 29-12-2013 by Dany]

plante1999 - 29-12-2013 at 09:08

Some are quite slow at research/working...

Try to make it and report about it.

simply RED - 29-12-2013 at 12:06

In 2005 I was only guessing about the compound and I never synthesized it. Well if all is true this should be the holly grail of improvised energetic materials.

Dany - 29-12-2013 at 12:12

Quote: Originally posted by simply RED  
In 2005 I was only guessing about the compound and I never synthesized it. Well if all is true this should be the holly grail of improvised energetic materials.


And now after 9 years of wondering and searching you can sleep well...:)

Dany.

[Edited on 29-12-2013 by Dany]

Fantasma4500 - 29-12-2013 at 18:25

interesting stuff, but it seems very stable -- nearly too stable
wonder if any sentisizers could be added, strangely phosphorus seems to make the road to DDT with open combustion of ETN much shorter.. havent seen direct proof of it -- yet, although ETN is already quite sensitive so theres no practical use for sentisizing it..

but if its so heat resistant, i suppose it doesnt melt at the experimental temperatures...?
often when compounds melt they decompose, and this was not the case with this compound

Metacelsus - 29-12-2013 at 18:50

Melamine perchlorate is so stable that it has been considered for a rocket propellant:

http://www.google.com/patents/US3110641

[Edited on 30-12-2013 by Cheddite Cheese]

roXefeller - 29-12-2013 at 19:32

Dany, if the density of RDX is 1.82 and this has a density of 1.85, then there should be a possibility of higher brisance if the packing density can get near the 1.6 level, correct? And the better rhetorical question is what brisance is needed to set it off with its drop hammer results.

Oh yeah, don't mention it comes from urea or else people will label it the next urine bomb with military level performance.

[Edited on 30-12-2013 by roXefeller]

[Edited on 30-12-2013 by roXefeller]

roXefeller - 29-12-2013 at 21:20

I just thought about critical diameter. It's most likely going to have a high value given its stability. Goebel didn't have a value estimated, the patent neither.

Dany - 30-12-2013 at 02:46

Quote: Originally posted by roXefeller  
Dany, if the density of RDX is 1.82 and this has a density of 1.85, then there should be a possibility of higher brisance if the packing density can get near the 1.6 level, correct? And the better rhetorical question is what brisance is needed to set it off with its drop hammer results


The performance of an explosive depend on many factors, not only density. you cannot compare two type of explosives each having it's own characteristics (different oxygen balance, different chemical composition, different heat of formation, different gas composition when detonate...). If the melaminium dinitrate possess higher density than RDX dosent mean that it is more powerful or "brisant". One simple example is TKX-50 explosive. This explosive has a density of 1.877 g/cm3. Although smaller than HMX density which is 1.90-1.91 g/cm3 the former (TKX-50) is superior in term of detonation performance. Yes, crystal density is important but it is not the only factor that determine the performance of an explosive. I suggest you roXefeller to read the paper of Peter POLITZER (a theoretical chemist working on high energy density materials):

http://www.wydawnictwa.ipo.waw.pl/cejem/Cejem-8-3-2011/Polit...

in this paper POLITZER shows the importance of other factors (other than density) in the final detonation performance of an explosive.

For the critical diameter that you just asked, yes Goebel didn't measure or estimate the critical diameter for a simple reason. First there is dozens of test that can be performed on an explosive molecule. Most of these test require substantial amount of the explosive material which is not always possible. the most important thing is that these test are difficult, time consuming and cost so much that it is impossible to make all test on an explosive. Only the urgent properties are explored like detonation performance and sensitivity. Predicting the critical diameter is hard and not reliable. Detonation scientist will make all these test if the explosive under investigation shows very promising preliminary results (like high detonation performance, insensitivity...).
In general an insensitive explosive possess a high critical diameter. however there is some exception. DAAF or Diaminoazoxyfurazan (an explosive synthesized in the soviet union in the 80's) is classified as an insensitive explosive but has very small critical diameter approx. 1 mm.

for further reading about test on explosive and DAAF i suggest reading this very informative study:

http://www.sciencemadness.org/talk/viewthread.php?tid=25475#...

Dany.

roXefeller - 30-12-2013 at 12:45

Thanks for the explanation, that looks like really excellent reading.

simply RED - 31-12-2013 at 01:21

Does the dinitrate require extreme excess nitric acid which renders its synthesis as difficult as RDX?

Dany - 31-12-2013 at 02:12

Quote: Originally posted by simply RED  
Does the dinitrate require extreme excess nitric acid which renders its synthesis as difficult as RDX?


From GOEBEL procedure you need 100 equivalent of nitric acid to undergo the nitration. However, as you can see the concentration of HNO3 is relatively low (65%) which can be bought easily in many country. To obtain good yields for RDX, you need 90%+ concentration which is more difficult to buy (or make). From the procedure of making the melaminium dinitrate i would say that this synthesis is classical and simple.

Dany.

physics inclination - 2-9-2017 at 19:03

If melamine were reacted with a more potent acid than nitric acid, such as high-purity sulfuric acid, do you think it would produce the thrice-protonated cation melaminium 3+?
If so, then that melaminium 3+ sulfate salt (or whatever other acid anion) could be converted to melaminium trinitrate by reacting with e.g. calcium nitrate. Melaminium trinitrate would likely be more desirable because of better oxygen balance than the dinitrate, I believe the numbers are about -7% and -25% respectively [source is that link someone posted earlier http://parazite.nn.fi/roguesci/index.php/t-4256.html].

nitro-genes - 3-9-2017 at 02:32

Even if it would exist: MTN <--> MDN + HNO3. The MDN in strong nitric could also undergo hydrolytic nitration, forming the corresponding nitramines in moderate yields, the most studied being dinitroammeline or DNAM, proposed for propellant use. IIRC, it's main drawback is being very susceptible to acid catalysed hydrolysis in itself. Salts of DNAM could also be interesting, still on my list of things to try one day... :)

[Edited on 3-9-2017 by nitro-genes]

PHILOU Zrealone - 3-9-2017 at 05:53

Melamine is a good building block for energetics because it:
-is densophoric (increases density),
-allows for good packing (pi stacking),
-brings some energy rich fuel (N=C linkages ... would be better with C#N but then you loose the stability and density increase of the aromatic ring),
-brings some good OB level (the N atoms reduce the OB vs C or CH)

The external NH2 brings some basicity what allows for salt formation (also densophoric because helping cristallinity and providing charges (-) and (+) thus increasing electrostatic cohesion).

But there is a problem inherent to the N atoms into the aromatic triazine ring...
1°) they increase electronegativity of the ring and hence they reduce the basicity of the external NH2 (read they increase their acidity);
2°) each protonation of an external NH2 reduces further the basicity of the other NH2(s)...
==> This explains that HC(NO2)3 (nitroform) can only afword a monosalt (about the power of TNT)... a disalt or a trisalt would be a killer... but they doesn't exist as a single compound but more like a binary mix of Melamine mononitroformate and nitroformic acid ... what may be also of interest...
==> Same applies to HNO3 what is a little stronger acid than nitroformic acid... so mono salt exists and the disalt also but the second protonation renders the compound very hydrolytically unstable... hence corrosive because releasing easily one of its HNO3... If a trisalt ever existed, it would be very unstable and equivalent to a mix of mono salt, disalt and HNO3.
This may explain the need of hurge exces of diluted HNO3 in the making and precipitation of MDN (melamine dinitrate)...
Melamine+ HNO3 <--==> MN (melamine nitrate)
MN + HNO3 <==> MDN
So to push the equilibrium to the right throught the two reactions, one needs a lot of HNO3... the exces HNO3 also helps precipitation and crystalization via the common anionic effect...
HNO3 <--==> H(+) + NO3(-)
M(2+)(Aq) + 2 NO3(-)(Aq) <==> MDN(s)

==> The use of a stronger acid is an excellent idea...and so perchloric acid is the best...it can afword a disalt...and maybe an hydrolytically unstable trisalt...

As a rule of tumb perchlorate salts are denser, display a better OB, higher sensitivity to initiation and are more brisant than their nitrate brothers... so their VOD also; but the chlorine atom makes those "unfriendly" for weapon barrels, and during the deflagration/detonation they release Cl2 and HCl (but do you really care for toxic/corrosive gases and enemies lungs health when shooting a bomb at the enemy)... it is more of a concern for civilian use of explosives or for mining in confined space...
At least space launcher propellant don't really care for that... since Ammonium perchlorate based ;)...

So what are the solutions to use the best of Melamine properties?
A) Use stronger oxoacids thus displaying stronger acidities in the hope to reach a stable trisalt not too hydrolytically unstable...
But this is not easy; since HClO4 is already very high on the list if not the highest.
Also despite increasing the acidity of the acid in the hope to allow for the basic expression of a mild to medium acid molecule (melamine, melamine monoprotonated, melamine diprotonated and melamine triprotonated)...
As a rule of tumb each protonation will increase the acidity by 3-4 pKa (pH) units and at the same time decrease the basicity (of the next NH2) by 3-4 pkb units... thus each time 1000-10000 times more acidic and less basic...
Thus the resulting salt even if stable will be corrosive to most metals and probably unfriendly for most plastics/organic material...so potent storage issues especially if in moist environment or not thoroughly dried.

B) Increase the acidity or the OB of the acid...
This is not possible except for HC(NO2)3... indeed one may imagine to work with pentanitroethane (PNE = nitroform with one of its NO2 relaced by a nitroformyl C(NO2)3 group) or heptanitropropane (HNP = nitroform with one of its NO2 relaced by a pentanitroethyl C(NO2)2-C(NO2)3 group)...
HNP must have a terminal C holding the H atom (and not the central one) otherwise the carbanion will be too bulkied and stressed by the two surrounding C(NO2)3...

What is the point of doing so? When doing this even if the protonation only allows for a monosalt; then the OB and density of the overal molecule will be better than the monosalt of nitroform...

Indeed HC2(NO2)5 (PNE) will be more acidic than HC(NO2)3 and HC3(NO2)7 (HNP) even more...

Also PNE afwords 6 active oxygen atoms vs 4 for nitroform (NF) and HNP even 8...thus one HNP anion is equivalent to two NF for OB!
HC(NO2)3 ==> 1/2 H2 + CO2 + 2 O2
HC2(NO2)5 ==> 1/2 H2 + 2 CO2 + 3 O2
HC3(NO2)7 ==> 1/2 H2 + 3 CO2 + 4 O2

As a bonus the heat of detonation from the anion will be much higher because it burns more CO2
HNP > PNE > NF... for energy release and even better HNP > 2 NF ...

Another good point is that HNP > PNE > NF with regard to density (there is no doubt about this if you consider the densities of NF, TNM (tetranitromethane) and HNE(hexanitroethane) and that you do a little calculation based onto conventional additive groups theories); so there is a chance the tendency of the monosalts afwords the same increasing patern... ==> HNP denser than PNE itself denser than NF...

And as a bonus HNP and PNE being more acidic may even form disalts what NF can't do

Of course such salts will be very very sensitive and extremely powerful

But now remains the synthesis of the anions PNE and HNP what is probably not an easy road...

C) Increase the basicity of the NH2 moeities by grafting something onto it...
This is the easiest way to go...

==>Grafting a NH2 onto the NH2... so NH-NH2 (hydrazino) will take the protonation charge a little away from the aromatic core...and so the basicity will be less influenced by the ring...the extreme outer NH2 will be favourised for protonation vs the one (NH) taken between the NH2 and the aromatic ring...
So study of trihydrazino-triazine salts of HNO3, HClO4, HBrO4 (probably too oxydant for hydrazino moety), HC(NO2)3 (and maybe HNP and PNE) should be a good idea

==> Grafting a amidine group (-C(=NH)-NH2) ... so one would end with a triazine ring with 3 guanidyl groups... guanidine is very basic so this may provide a good way to reach easier disalts and maybe trisalts... the guanidine is also a densophoric group and a rich at energy fuel.

D) Working onto other melamine/triazine related molecules...
==> Triamino-Heptazine (melem) comes to mind...
It can be done by heating melamine...
Here is the structure of the heptazine core...

The related triazido-heptazine is a known explosive compound (C3N7(N3)3 = C3N16) but I found very little info about it.

Why should it be interesting?
-The extended planar aromatic ring should increase the density...vs melamine
-Separation of the NH2 should help making disalt and maybe trisalts
-It has naturally a better OB than melamine (-110% vs -114%)

So...
==> Triamino-heptazine-dinitroformiate
C3N7(NH2)3. 2HC(NO2)3
==> Maybe Triamino-heptazine-trinitroformiate
C3N7(NH2)3. 3HC(NO2)3

And Triamino-heptazine-
==> di-/tri-perchlorate, di/tri-nitrate
==> di-/tri-pentanitroethanate (PNE)
==> di-/tri-heptanitropropanate (HNP)


[Edited on 4-9-2017 by PHILOU Zrealone]

PHILOU Zrealone - 10-9-2017 at 14:34

For the previous heptazine compounds each C3 must become C6... the edit buton is not available anymore...

D) Working onto other melamine/triazine related molecules...
==> Triamino-Heptazine (melem) comes to mind...
It can be done by heating melamine...
Here is the structure of the heptazine core...

The related triazido-heptazine is a known explosive compound (C6N7(N3)3 = C6N16) but I found very little info about it.

Why should it be interesting?
-The extended planar aromatic ring should increase the density...vs melamine
-Separation of the NH2 should help making disalt and maybe trisalts
-It has naturally a better OB than melamine (-110% vs -114%)

So...
==> Triamino-heptazine-dinitroformiate
C6N7(NH2)3. 2HC(NO2)3
==> Maybe Triamino-heptazine-trinitroformiate
C6N7(NH2)3. 3HC(NO2)3

And Triamino-heptazine-
==> di-/tri-perchlorate, di/tri-nitrate
==> di-/tri-pentanitroethanate (PNE)
==> di-/tri-heptanitropropanate (HNP)