Σldritch
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Safty in making large quantities of Copper Acetylide
For an upcoming project i need to make at least several grams of Copper Acetylide. Because of its sensitivity i want to know how i can minimize the
hazard.
What i plan to do now:
1. Protective equipment such as glasses and gloves.
2. Divide it into small batches a' one gram.
3. Use plastic beaker.
4. Tongs for all handling.
5. No stirring rod, only swirling.
5. Always keep it suspened in liquid. (The project does not require dry Copper Acetylide)
Anything else? Is silver acetylide safer?
[Edited on 23-1-2018 by Σldritch]
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Sulaiman
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I know nothing about copper acetylide other than it behaves like silver acetylide,
which I used to play with as a youth - great fun.
As it can be made quickly (or even in-situ ?) I guess that you should make small batches as and when required,
and keep it wet.
CAUTION : Hobby Chemist, not Professional or even Amateur
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The Austrian Scientist
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Are you planning to do Reppe chemistry, since Cu2C2 is uesed there as a catalyst
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Metacelsus
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What exactly do you need it for? There could be possible substitutes.
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greenlight
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Cuprous acetylide (Cu2C2) has a relatively low sensitivity according to what I have read. It is also one of the only acetylides to find practical use
with explosives in electric fuse head compositions which says something.
The real sensitive one is cupric acetylide (CuC2) which I am unsure whether it can form as an impurity in the cuprous acetylide synthesis.
I never make more than a few of grams of primary just for making detonators and its is divided into smaller piles to dry. Maybe make a very small
amount first to test sensitivity as the synthesis is not complicated
Use all the safety equipment you have listed and just try to maintain distance from the actual explosive at all times (plastic tongs).
Also remember just because it is wet doesnt mean it is not sensitive to initiation. Some primaries are the same wet or dry.
Be good, otherwise be good at it 
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Σldritch
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I do not need it for its explosive properties nor is it for Rappe chemistry, i want to keep it secret until its done, but ill make sure to post the
results when it is done. I have looked really hard for something that none else has done for this project so i want to be careful.
There inevitably is some cupric ions formed from oxidation by air. If cupric acetylide is more sensitive could i add some reducing agent to the
ammonia? I do not have any bisulfate which is the obvious choice. Could dithionite work? I imagine it might form sulfides, copper metal or even reduce
the acetylene! Guess i could try it without the acetylene.
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greenlight
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From primary explosives:
"In order to limit the oxidation of the cuprous salt to cupric and hence prevent the formation of cupric acetylide, a number of authors recommend the
presence of a reducing agents (hydroxylamine, sulfur dioxide, hydrazine sulfate, etc).
According to these authors, the product prepared from ammoniacal solution of cuprous chloride in the presence of any of hydrazine hydrochloride,
hydroxylamine hydrochloride, or formaldehyde has lower explosive properties than product prepared in the usual way"
[Edited on 25-1-2018 by greenlight]
Be good, otherwise be good at it
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AJKOER
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My take on the process is the need for moisture, O2 and a source of H+. The latter could arise from the presence of an acid gas (like CO2) or from a
hydrolysis in the presence of sufficient water assuming the creation of a soluble cuprous complex or an existing cupric complex via:
[Cu(H2O)6]+ (aq) --> [Cu(H2O)5(OH)](s) + H+
[Cu(H2O)6]2+ (aq) --> [Cu(H2O)4(OH)2](s) + 2 H+
Next, an electrochemical formation of Cu(OH)2 and/or a basic salt via:
Cu(+) (aq) + O2 + 2 H+ (aq) --> Cu(OH)2
Also, the action of CO2/H2O on Cu2C2 could release C2H2:
Cu2C2 + CO2 + H2O --> Cu2CO3 + C2H2
and this could result in the formation of the problematic cupric acetylide (I would speculate that both the cuprous and cupric products are mixed
salts, with the latter of the form CuC2.nCu where n>2 due to the reducing ability of C2H2 acting on metal oxides, see https://ac.els-cdn.com/S1877705814027994/1-s2.0-S18777058140...) while also regenerating water:
CuO + C2H2 --> CuC2 + H2O (Source on CuC2, see https://chem.nlm.nih.gov/chemidplus/sid/0012540135 )
Per this quick analysis, I suspect that employing a drying agent, removing water, may be a valuable preventive also. Perhaps, a small test tube of
NaOH in a jar with Cu2C2 addressing both possible water and CO2 presence.
[Edited on 27-1-2018 by AJKOER]
[Edited on 28-1-2018 by AJKOER]
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Σldritch
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As I am not intending to store the Copper (I) Acetylide, displacing the air with Acetylene seems to be the simplest solution. I should probably use a
narrow container by that reasoning.
On exluding water; i thought about using another solvent such as acetone but that would require me to change solvent later in the process which
negates the benefits it could bring such as the increased solubility of acetylene and lack of water. (If Cuprous Chloride is soluble in it).
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AJKOER
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Further review of the literature suggests that the selected path to Cu2C2 can actually produce many compounds. See the discussion at http://copper.atomistry.com/cuprous_acetylide.html , to quote:
"The Cuprous acetylide, Cu2C2, is formed by the action of acetylene on an ammoniacal solution of cuprous chloride, or on a suspension of cuprous oxide
in water. It is a brownish-red, amorphous substance, and explosive in the dry state. Prepared by the first method, it is associated with a molecule of
water, which can be removed by drying over sulphuric acid. The presence of this water has been attributed to adsorption, and another explanation
assumes the compound to have the formula CH≡CCu,CuOH. ...........Manchot found that excess of acetylene combines with cuprous chloride to form white
crystals of the formula CuCl,C2H2."
For more comments by another source, see http://onlinelibrary.wiley.com/doi/10.1002/jctb.5000661007/e... .
I would recommend a slower reaction path than ammonia based that, however, does not require days of drying over H2SO4, namely the direct action of
C2H2 on a water suspension of Cu2O (likely best with a fresh participate of Cu2O) resulting in a less 'complex' product.
Note, the copper acetylide products created can apparently vary in composition from Cu2C2 to Cu2C even for the cuprous compound!
[Edited on 28-1-2018 by AJKOER]
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