Sciencemadness Discussion Board

Silver Acetylide Advice

tgfuzzball - 8-11-2011 at 16:31

Hello everyone! I am an AP Chem student who also works for a university education outreach program. For one of our podcasts, I thought it might be interesting to demonstrate the difference between deflagration and detonation.

After some research, it seems that silver acetylide has a fairly doable synthesis and is stable enough that I can make small amounts safely. However, I will clearly state now that I have absolutely no experience whatsoever with energetic materials, but I also have a great desire to keep all of my digits in functioning order.

After reading most of the threads here regarding silver acetylide, I have a few questions:
- Is there any way to neutralize the silver acetylide after the synthesis? I probably won't want to detonate it all.

- How do I lessen the danger of detonation from a static shock? (other than grounding myself before contacting it, etc.)

- How long does wet silver acytelide take to dry at room temperature (~23 *C)

- Is there anything I should know that I don't?

- Is there a safer primary explosive which I can synthesize reliably? I'd like to use DDNP, but it seems very difficult to synthesize.

Thank you for all of your time.

-tgfuzzball

[Edited on 9-11-2011 by tgfuzzball]

The_Davster - 8-11-2011 at 22:17

-Sodium hydroxide will destroy it

-beyond groundign not much you can do. work in a moist atmosphere. Work with maybe 200mg at a time so if it goes off you just have ringing ears

-depends on humidity. I overnight is usually sufficient.

-keep the amount small. I would make around 1g total, and dry it in 200mg portions at most. Do not confine when dry in glass. Always maximize the distance between hand and dry material (ex clamps holding reaction vessel, not your hand)

-not that will undergo a good DDT in small amounts.

Formatik - 9-11-2011 at 21:39

Quote: Originally posted by tgfuzzball  
- Is there any way to neutralize the silver acetylide after the synthesis? I probably won't want to detonate it all.


Added portionwise into conc. aq. strong acids (like HCl) liberates the acetylene.
Quote:
- How do I lessen the danger of detonation from a static shock? (other than grounding myself before contacting it, etc.)


Don't wear clothes a lot that you notice tend to generate static shock. Polyester is significantly more negative in the triboelectric series than cotton relative to human skin, so when the fibers and skin are rubbed against each other it generates static shock quite readily. Warm temperature with humidity decreases static risk. If pouring and agitating, do so slowly. There some measures against static shock outlined here.
Quote:
- How long does wet silver acytelide take to dry at room temperature (~23 *C)


If you wash with water it takes something like a half a day usually, or more. With a subsequent alcohol wash it takes minutes to hours. Even faster with a following ether wash. If you then vacuum filter, it's good to use right after the washes.
Quote:
- Is there anything I should know that I don't?


Gauge the risk. 0.5g of silver acetylide is enough to remove major portions of a hand and fingers. So don't handle it directly on your hands. It is better to "grab" primaries (in the milligram amount) by the filter paper, and then transfer parts of them using a long wooden match, aluminium foil piece, spatula, etc. One researcher Thomas Klapoetke wears kevlar gloves. The improvised thing would be something like doubled gloves (tough large workers gloves worn over thick PVC gloves). I've used the doubled gloves before when handeling a compound I suspected was silver azidotetrazolate. Ear plugs are essential and a face shield. Thick clothes. I avoid glass with the primaries because of shrapnel risk and increased direct force risk, preferring e.g. a plastic beaker instead.
Quote:
- Is there a safer primary explosive which I can synthesize reliably? I'd like to use DDNP, but it seems very difficult to synthesize.


You are probably picking silver acetylide based on its high and excellant flame sensitivity. Flame contact sensitive materials aren't needed for a good demonstration though, just heat from underneath instead. Good detonators will bang under this circumstance.

For more effort a safe, relatively low sensitivity silver salt (simple hammer blows don't detonate it) can readily be made from aminotetrazole which is far more powerful than silver acetylide.

PHILOU Zrealone - 10-11-2011 at 14:03

Avoid too much sunlight exposure

and

Avoid friction especially if the salt is black-brown instead of creamy white-to pale grey (dark variant usually occurs when some AgNO3 is left unreacted, when tap water instead of demineralised-water is used or when some Ca(OH)2 interracts from the gaz generating system and the bubbling reactor)

Formatik - 27-12-2011 at 21:32

Lead azide comes closest to what you are asking I think, it is safe enough to be used in commercial detonators and has the flame sensitivity of some silver salts.

I've exposed several compounds including copper and silver diazoaminotetrazolate, tetrazene, the green powder from a .22 cal shell, silver azotetrazolate, sodium azotetrazolate pentahydrate, and lead azide to piezoelectric sparks (from a barbeque lighter). The sparks are strong enough that one can feel them on the skin, but not quite as strong as some humans can generate. But out of all of these compounds only the silver azotetrazolate salt detonated. I also think in the silver acetylide static discharge thread another member exposed silver acetylide to one of these types of piezoelectric sparks and it detonated.

Another thing to watch out for is confinement, primaries detonate a lot more powerfully when confined. A force acting on the material vertically is enough to simulate confinement.

[Edited on 28-12-2011 by Formatik]

hissingnoise - 28-12-2011 at 02:21

Ag<sub>2</sub>C<sub>2</sub> produces only solids on detonation.
But anything in very close proximity will, of course, suffer damage . . .


caterpillar - 10-1-2012 at 16:27

There are two sorts of silver acetylide. One may be obtained from AgNO3, dissolved in ammonim sollution. This one is more sensitive and has a lower performace compared with complex Ag2C2+AgNO3. This one can be obtained from warm solution of AgNO3 in diluted HNO3. This last one is better for primers.

neptunium - 10-1-2012 at 16:45

primarys are fun arent they?

if you want an effective primary for a demonstration on detonation nitrogen tri iodide comes to mind ....but copper acetylite is cheaper than silver and easier to manufacture.
just bubble acetylene in copper (ll) chloride and your done when you have enough precipitate.
filter and let it dry over night.
your done .
again NI3 is easier yet and makes for great demonstration.
stirr I2 in ammonia (conc) filter and let it dry.
wherever you deceide to let it dry is where you will detonate it
DO NOT move it arround when dry.

i suppose deflagration could be demonstrate with the nitration of cotton or simple black powder

its your first and only post i hope you aint try to do anything stuppid right?

[Edited on 11-1-2012 by neptunium]

a_bab - 12-1-2012 at 08:31

If I were you I'd make a single gram of it and store it WET.

Before the actual demonstration you can wash with alcohol the amount needed for demonstration and let it evaporate. It takes very little time. Acetone is even better. 100 mg is PLENTY enough to prove your point in the front of your audience in a deafenining way.

Under any circumstances don't store it, especially dry.

And finally, you really don't want to be seen as a pyro addict by lots of peope, possibly for your entire wife do you? There are plenty of other demonstrations, that would probably be better received. Just google for some "funny interesting chemistry demonstrations".


For a safer and easier to make primary lead azide is a nice option albeit it requres sodium/potassium azide I'm sure your lab carries it. LA can be destroyed with NaOH. You can also put the precipitate in the flame as it is; once the water evaporates it goes off most of the times (or it turns to yellow lead oxide if the heating was too slow).


[Edited on 12-1-2012 by a_bab]

Aqua_Fortis_100% - 12-1-2012 at 13:33

Quote: Originally posted by a_bab  
If I were you I'd make a single gram of it and store it WET.

Before the actual demonstration you can wash with alcohol the amount needed for demonstration and let it evaporate. It takes very little time. Acetone is even better. 100 mg is PLENTY enough to prove your point in the front of your audience in a deafenining way.
[Edited on 12-1-2012 by a_bab]


Of course, use distilled water.. Tap water will slowly decompose it.

Like caterpillar said double salt SA is easier to make than neutral Ag2C2 and somewhat 'safer', more powerful and unlike Ag2C2, wont change its color when exposed to light.

caterpillar - 13-1-2012 at 14:28

I tryed to make Cu2C2. Nothing useful, obtained precipitate didn't want to explode at all. Surely I made somethig wrong. Neutral Ag2C2 produced big Bang, but was unable to initiate picric acid. Deflagration can be demonstrated by piroxiline or kalium salt of picric acid. Or put NH4NO3 onto hot steel plate.

neptunium - 13-1-2012 at 16:27

it wont work with copper sulfate you have to first make a solution of copper chloride...but if you got it to work with silver why the hell not!;)
picric salt detonate . ammonium nitrate and diessel deflagrate its a rapid combustion.
again , nitrogen tri iodide is probably the easiest primary arround.
always small amount is the golden rule!
good luck and have fun!

caterpillar - 13-1-2012 at 22:46

I made Cu2Cl2, then put it into ammonia solution and bubbled C2H2. No matter, later I realized that the best primer (well, one of the best) is acetone triperoxide. Picric salt detonates even been ignited in confinment- on open ear it deflagrates. Nitrogen tri iodide may be good for demonstration, but as a primer it is too sensitive.