Preparation of silver acetylide

[woelen]

Here is a description of an experiment, which I did with the preparatoin and detonation of silver acetylide. This is a very nice experiment, but one has to be careful.

 

This explosive is not suitable for high volume preparation. The cost of it is very high (it is based on silver ), but in small quantities it shown interesting properties.

 

If you have the chems, it definitely is worth yo try this, and it can be done safely, if the safety guidelines, given on the webpage are followed:

 

http://woelen.scheikunde.net/science/chem/exps/silveracetylide/index.html

[warut]

Wow! Is it possible to cut the cost by making Cu2C2 instead?

[RyanJ]

Cool experiment Woelen, thanks for sharing

 

-- Ryan Jones

[jdurg]

The remarkable thing about silver acetylide is that it isn't really a "classic explosive". It contains no nitrogen and no oxygen, and doesn't really consist of a "typical" fuel and oxidizer. The reaction products are also both solids (Ag and C) since the melting points of both products are WELL above the temperatures reached by the reaction. Therefore there is little to no smoke or vapor produced by the detonation. Only solid remnants. (A tiny bit of the carbon may initially oxidize to form miniscule amounts of CO or CO2).

 

Since no gas is formed, one may wonder why there is any sound at all when Ag2C2 detonates. The reason you do have a sound is that a great deal of energy is released by the detonation which smacks the molecules in the air around it. This results in the creation of a brief, but intense energetic wave akin to when a hammer strikes the surface of something.

 

The detonation of a normal explosive results in a great deal of energy being imparted into the newly formed gaseous molecules. This causes a massive outrush of gas from the detonation, and the air that replaces the outward moving gas will smack together giving a nice "kaboom".

[woelen]

Wow! Is it possible to cut the cost by making Cu2C2 instead?

No, unfortunately it is not. It can be prepared, but it is a lot more difficult. Cu2C2 reacts with water, forming Cu2O and C2H2.

 

It can be prepared by bubbling C2H2 through a solution of CuCl2 and immediate filtration of the precipitate and rinsing with absolute ethanol. Drying must be done in a vacuum desiccator.

 

You see, the synthesis of Cu2C2 is much more difficult to perform in a home lab. I've not tried it, because I do not have anhydrous ethanol and I have no vacuum desiccator. I did try bubbling C2H2 through a solution of a copper salt, but I only obtained red/orange Cu2O.

[warut]

Thanks for the very interesting info, jdurg & woelen.

 

IIRC, in basic organic chemistry lab we use ammoniacal solution of cuprous chloride to test for terminal alkynes. So is it a good idea to try using this instead of a simple copper salt solution?

 

BTW, woelen, are you sure that the red ppt. is Cu2O, not Cu2C2. Have you tried detonating it? Do we need to dry it before igniting?