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VladimirLem
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thumbup.gif posted on 8-10-2013 at 09:07
Short question / quick answer - Thread


Hi there

I think this forum needs some thread like this...it really sucks always to start new threads or post in (old) threads, which are often only a bit related to the question...

well so i start and hoping no mod/admin dislike my idea :(

i allways read from qeople using hexamine dinitrate at the RDX symnthesis but i've never seen a more hygroscopical comound like this and even a friend who had alot of expierience at chemistry is desperat at not getting HDN dry...anyone have an (efficient) idea how to get that dry?



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[*] posted on 8-10-2013 at 09:10


The Short Questions Thread (4)

I see no harm in an EM-specific short question thread.




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DubaiAmateurRocketry
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[*] posted on 27-12-2013 at 17:42


Actually, I want to point out that a short question thread especially for EM is very favorable because one can receive much better quality/useful reply/anwers when people who are into energetic materials ask and answer in the same place.

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DubaiAmateurRocketry
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[*] posted on 27-12-2013 at 17:50


Okay let me start the first question here, sorry for double posting.

When I was almost purchasing Hydroxylammonium salt where I would ion exchange for hydroxylammonium perchlorate, a member, Anders Hoveland pointed out it has an impact sensitivity of 2J !!!! Impossible I thought, since its patented so much and synthesized on such large batches in their patents, so I wonder if his claim is true. I have a hard time finding its sensitivity. I guess its so insensitive it does not need such a scale to measure it ? I havent seen an explosive so sensitive and having OB of over +40 at same time.

Thank any one who can help this. dar.
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Dany
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[*] posted on 27-12-2013 at 19:19


US patent 2768874, indicate that hydroxylammonium perchlorate has an impact sensitivity of 15 which according to the patent represent the distance in centimeters a 2 kilogram weight was required to fall in order to produce 50% shots (determined on Bureau of Mines impact machine). However, as it is known the value of sensitivity of energetic material can vary considerably between different test and configuration.

Dany.

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Dany
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[*] posted on 27-12-2013 at 19:43


DAR,

i will give you some examples of impact sensitivity of certain type of explosives taken also on the same machine (Bureau of Mines impact machine) so as to be able to compare with the sensitivity of hydroxylammonium perchlorate.

First the testing machine is fully described in Military Explosives (TM 9-1300-214 ARMY TECHNICAL MANUAL) chapter 5 (section 5-6) and the values are also extracted from this manual:

Mercury fulminate: 5cm
Tetracene: 7 cm
HMX: 32 cm (for 20 milligram sample)

You should be careful when comparing the sensitivity with your hydroxylammonium perchlorate since as i mentioned the sensitivity can vary even on the same apparatus, one factor may be the crystals morphology of the explosive being tested.

Dany.
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DubaiAmateurRocketry
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[*] posted on 27-12-2013 at 20:57


Wow Thank you dany! I will synthesize a gram or less and see its sensitivity next few month. Still surprised at the high sensitivity. 15cm and 2kg is around 3 joules (similar to ETN) However I expect it to have only a moderate VoD. I might also synthesize a gram of Hydroxylammonium dinitramide from KN(NO2)2 and Hydroxylammonium perchlorate/sulfate(i'm pretty sure they will ion exchange). What surprised me is they obtained the dry form of the salt.



From This Article


Does Ammonium perchlorate and Potassium dinitramide ion exchange for Ammonium dinitramide ? It seems all okay but ADN's solubility is far higher than Ammonium perchlorate. In papers they used Ammonium sulfate, however I think just for more economic ? However I have few kg of AP sitting here and dont want to buy more ammonium sulfate.


[Edited on 28-12-2013 by DubaiAmateurRocketry]
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roXefeller
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[*] posted on 27-12-2013 at 21:32


Vlad, did your friend try washing in acetone or ethanol and then low temp dessicator? I know this is the canned internet method but I'm curious if his results didn't live up to expectations.
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[*] posted on 28-12-2013 at 03:03


DAR,

The specific impulse of hydroxylammonium perchlorate(NH4ClO5)/hydrazine (optimal mixture) is approx. Isp=262 s, see [1] page 244.

other interesting physical properties for NH4ClO5 is found in [2]. for example, the crystal density of NH4ClO5 is 2.06 g/cm3 and heat of formation @ 298 °K HOF= -66.5 kcal/mol.

Dany.


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[Edited on 28-12-2013 by Dany]
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DubaiAmateurRocketry
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[*] posted on 28-12-2013 at 08:29


Yes thank you dany, not only the specific impulse is higher, Hydroxylammonium perchlorate(HAP) also have much higher density than AP. from PROPEP code HAP give nearly 10s higher than AP if directly replaced. This is a very high increase. unfortunately its impact sensitivity is too high.

The [1] paper seems to have undercalculated many explosives. paper [2] seems to treat HAP as a normal compound without sensitivity. It wont even ignite in pressure slightly lower than ambient pressure. I'm still in doubt in the real impact sensitivity of HAP and I will set up my own 2.5kg steel ball weight dropper to test it in the coming few month. Only if my shipping goes cross the strict boarder of Dubai though.

Do you know the impact sensitivity of potassium dinitramide(KDN)? My search engine have ammonium dinitramide overlaping it and most papers I found only use KDN as a intermediate for ADN and does not provide any impact sensitivity for KDN.
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[*] posted on 28-12-2013 at 09:18


Quote: Originally posted by DubaiAmateurRocketry  
Do you know the impact sensitivity of potassium dinitramide(KDN)? My search engine have ammonium dinitramide overlaping it and most papers I found only use KDN as a intermediate for ADN and does not provide any impact sensitivity for KDN.


Yes, this article is very useful (see table. 2)

Dany.

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[Edited on 28-12-2013 by Dany]
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[*] posted on 28-12-2013 at 10:45


Quote: Originally posted by Dany  

Yes, this article is very useful (see table. 2)

Dany.

[Edited on 28-12-2013 by Dany]



Ahh I see, over 20 J is a very nice and safe for handling. Thank you.
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[*] posted on 29-12-2013 at 06:43


In this paper

http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1521-4087(199906)24:03%3C159::AID-PREP159%3E3.0.CO;2-0/abstract

The conversion of ethylene glycol bis-chloroacetate to ethylene glycol bis-azidoacetate was done using DMSO. can it be repeated with DMF ? or is there some special reason for the use of DMSO ? other than tocxity ?
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Dany
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[*] posted on 29-12-2013 at 07:03


Quote: Originally posted by DubaiAmateurRocketry  
The conversion of ethylene glycol bis-chloroacetate to ethylene glycol bis-azidoacetate was done using DMSO. can it be repeated with DMF ? or is there some special reason for the use of DMSO ? other than tocxity ?


DMF and DMSO are classical solvent for SN2 reactions like the one encountered here. The choice of the solvent should be optimized to meet the requirement of high yield products, minimum time reaction and minimum side products. This is done during the course of the study, however, this is not written in the scientific paper. what you see in these article is the final result of the optimizing procedure done by the author of this study. This is not necessarily the best result that can be obtained, other way can be explored to achieve better results. So maybe the authors used the DMF and found that is inferior to DMSO for carrying this reaction.

Dany.
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[*] posted on 29-12-2013 at 13:02


Thank you dany.

Any one know why many energetic compound's deutrated form has been synthesised ?

Another question. Does Ammonium perchlorate ion exchange with Potassium dinitramide to form KP and ADN ? Almost all papers that says ADN from KDN uses ammonium sulfate.

What about this ? NH4ClO4 + KNO3 = KClO4 + NH4NO3. KClO4 is less soluable however ammonium nitrate is more soluable so .. is this reaction possible ?


[Edited on 29-12-2013 by DubaiAmateurRocketry]
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[*] posted on 29-12-2013 at 15:33


Quote: Originally posted by DubaiAmateurRocketry  

Any one know why many energetic compound's deuterated form has been synthesized ?


For NMR, maybe? (Although that usually involves deuterated solvents . . . Maybe they want to eliminate the signal from certain protons for some reason?)

[unfounded speculation] For some strange, classified application in nukes??? [/unfounded speculation]




As below, so above.
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[*] posted on 29-12-2013 at 16:38


DAR,

isotopically labelled explosive where synthesized for detonation experiment like the explosive nitromethane. Deuterated nitromethane shows interesting properties over normal nitromethane. For example, the critical diameter of deuterated nitromethane in glass is more than double the critical diameter of normal nitromethane see:

http://library.lanl.gov/cgi-bin/getfile?00789342.pdf

also 14C labeled HMX has been synthesized for biodegradation studies see:

http://onlinelibrary.wiley.com/doi/10.1002/%28SICI%291099-13...

Dany.
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[*] posted on 31-12-2013 at 08:23


I have a question that has been bugging me for some days... is there any type of hand protection that can successfully prevent them from tearing apart by, say... as low as a gram of a HE?

I know EOD (bomb squad) doesn't use gloves for mobility, but also they deal with *much* more a gram of them explosives.

If there is, any availability for the amateur?
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[*] posted on 31-12-2013 at 08:43


Heavy finger weighted gloves maybe?
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Dany
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[*] posted on 31-12-2013 at 09:26


Quote: Originally posted by NexusDNA  
I have a question that has been bugging me for some days... is there any type of hand protection that can successfully prevent them from tearing apart by, say... as low as a gram of a HE?

I know EOD (bomb squad) doesn't use gloves for mobility, but also they deal with *much* more a gram of them explosives.

If there is, any availability for the amateur?


Working with explosive and high energy density materials are not suitable for beginners in the field of science and chemistry. before handling these materials, you should have good theoretical background on the sensitivity of these materials and what are the danger encountered during the handling. PhD student working on energetic materials subject must handle different type of explosive. If a student synthesize a new compound, nothing is known about it's properties so synthesis is realized on small quantities (100-200 milligrams). Synthesizing Bigger quantity are permitted only after a series of test (friction sensitivity, shock sensitivity, thermal analysis...) on the new compound are realized. During the handling, the student wear Kevlar gloves, and work is performed behind a safety shield. Anti-static materials are used to avoid any electrostatic discharge that can trigger detonation. For more on these protective gloves read this paper:

http://publik.tuwien.ac.at/files/PubDat_169519.pdf

Remember, that the best safety is to work with small amounts <250 milligrams. With small amount, it is likely (but not sure) that you will not loose a finger, a hand or a head...

Dany.



[Edited on 31-12-2013 by Dany]
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NexusDNA
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[*] posted on 31-12-2013 at 15:25


Thanks Dany. But as the paper suggests, even 1g of lead azide will tear steel-core kevlar gloves. Maybe we should work with our feet!

And happy new year to all of you!

[Edited on 31-12-2013 by NexusDNA]
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Dany
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[*] posted on 31-12-2013 at 15:44


Quote: Originally posted by NexusDNA  
Thanks Dany. But as the paper suggests, even 1g of lead azide will tear steel-core kevlar gloves. Maybe we should work with our feet!

And happy new year to all of you!

[Edited on 31-12-2013 by NexusDNA]

This example illustrate how crazy are some members here. Some have worked with grams of very sensitive peroxide explosive! You cannot handle this large quantity of peroxide (or other sensitive explosive) and say "i have the control of what i'm doing".

The reason of why any material can resist a detonation is the following:

when an explosive detonate near a material (the explosive is considered attached to this object with no space between them) the detonation wave that spread over the explosive charge has a velocity between 4-10 km/s and pressure in the range of 200-450 kbar. The Thought steel will yield (this mean will bend or fracture) when subject to a stress of 10-15 kbar so at 200-400 kbar rang the strength of any material can be neglected and the material is treated like a fluid. This why the branch of studying the detonation physics is fluid dynamics.

happy new year for you and all other members.

Dany.

[Edited on 31-12-2013 by Dany]
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[*] posted on 31-12-2013 at 17:41
Happy New Year


Stay safe all you western hemisphere pyrotechnicians. Don't come back with sad stories.
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[*] posted on 1-1-2014 at 08:01


why doesn't egdn is completely used instead of ng by dynamite factories?
couldn't the dynamite just go from egdn ?

[Edited on 1-1-2014 by Peroksit]
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[*] posted on 1-1-2014 at 08:15


EGDN has similar detonation properties as NG (although less dense 1.49g/cm3 for EGDN vs 1.59 g/cm3 for NG). EGDN has partially replaced NG in explosive industry the main advantage is that the freezing point of EGDN is lower than that of NG (-20°C for EGDN vs 13°C for NG).

Dany.

[Edited on 1-1-2014 by Dany]
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