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quicksilver
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I have had difficulty getting silver to dissolve fully in acid and found a trick to accomplish this......
Use silver wire! The smaller the size of the material the better. Note how AXT used powder. And then add a drop of water to the metal itself! Let's
say you don't have silver wire, get some silver and cut, rend or hammer it into a small piece. Then get it wet with water and THEN place it within the
acid. The water provides an O source for the start of the reaction and then it will continue with little fuss. Some people used to suggest drops of
water to the acid directly, but if you put it on the metals the reaction is much faster.
True detonation is a VERY interesting thing. TATP does not detonate according to the classical definition. But fulminates, styphnates, picrates, &
azides do! The bonds do break. And this can happen on a very tiny level. A single crystal of lead styphnate when held on the tip of a needle will
"pop" and a tiny sound can be heard! Same for fulminates; you can work on a micro scale.
Often the addition of starch to the Ag fulminate will "buffer" it so that it might be worked with in a somewhat safer manner. But the best suggestion
is to keep the whole of the experiment small. To me even a gram is a fair size batch 
To the best of my knowledge the above decomp formula by LEVI is correct: 2AgCNO --> 2Ag + N2 + 2CO. There are areas that may have some alteration
such as the environment of the material influencing the resultant but I think it's right on the money. That's why it's so interesting.....it really
breaks apart.
Get a good book on detonation modeling and read it very slowly....it's really something.
Also, asking questions here won't get you banned or yelled at.
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ssdd
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I may ahve some silver wire laying around amongst the masses of computer parts in my basement. That sounds like a safer/nicer way of going about this
than just taking the silver powder and dumping it into the acid which realeases tons of NOx gas. 
I am guessing because the triple bond bettween the Carbon and Nitrogen is where alot of the energy of the detonation comes from.
Any hints as to where I can find a book on detonation modeling?
(On the last line; Yea I was banished from roguesci (suprise!) for this same topic...) 
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gregxy
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I remember making silver fulminate 30 years ago when I was a teenager. We broke a tine off of a sterling silver fork, disolved it in HNO3 and added
ethanol. The mixture heats up and starts to boil and white powder percipitates out.
The reaction from alcohol to fulminate is described in the Davis book and has 6 or 7 steps. However it may also be possible to make fulminates from
nitromethane. The reaction
from HNO3 and ethanol requires mercury or silver since the
fulminate salt must be insoluable in the acid mixture to
form a percipitate.
silver fulminate is described as too sensitive to have any practical use, probably similar to TATP.
I was injured by it along with my friend when some fulminate that we had in a glass vial under water exploded. (We were
cut by the flying glass and our ears were ringing for about a week). I was very lucky not to loose an eye from the accident.
Never make more than a gram of this kind of stuff.
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Rosco Bodine
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There is also some more information in US4270435
and a bit more discussion in
https://sciencemadness.org/talk/viewthread.php?tid=1778&...
and
https://sciencemadness.org/talk/viewthread.php?tid=350&p...
[Edited on 16-4-2007 by Rosco Bodine]
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chemoleo
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If there are any posts on Silver fulminate that require moving/merging/deleting, let me know.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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ssdd
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Thanks for merging these.
I think I am going to revisit my work with fulminates tomorrow. Now that I have proper directions for producing it it should go better.  I must say the Fulminate molecule is pretty interesting now that I have looked into it
more. What I didn't know, as a few outlined above, is that the fulminate can detonate while submerged under water.
Would working on a scale of .5 grams of dissolved silver be a safe level to try this. Some of the places I looked said that it may not be enough
silver to maintain a reaction. Can anybody verify this?
Also, what are some suggested detonation methods for this that can be safely done in a high school lab?
Thanks for your help.
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quicksilver
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| Quote: | Originally posted by ssdd
Any hints as to where I can find a book on detonation modeling?
(On the last line; Yea I was banished from roguesci (suprise!) for this same topic...) |
A really good one is written by Fickett & Davis ( Detonation ). It is a good idea to spend a really long time on the first two chapters as it uses
them for the rest of the book and all the modeling concepts.
Most everyone here has been banned from there or just simply stopped posting there. It's fucking amazing how many people here also don't care about
racial hygiene or killing dogs. (yes, NBK)
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ssdd
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GAHHHH!!!!1!
Ok so I reattempted Silver Fulminate today. And yet again it failed. Heres what I did:
1. Dissolve 1.1 grams of silver into 20 ml of 3 molar Nitric Acid.
2. I heated this to 84*C, some NOx gas was realeased.
3. I let it cool down to about 60*C.
4. Added 20 ml of Ethyl.
5. Maintained the tempature of the liquid at 65*C for 25 minutes.
6. Let it start to cool, then added 100 ml of cold water.
The liquid became a milky blue/white. I attempted to filter it and was given a very small yeild of a shiny white material. This all seems to go wrong
at the end. What on earth happened, or better yet did I mess up somewhere along the way? 
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The_Davster
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You should have used concentrated nitric acid. The stuff you used is too dilute for the reaction with alcohol to occur.
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quicksilver
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| Quote: | Originally posted by ssdd
Ok so I reattempted Silver Fulminate today. And yet again it failed. Heres what I did:
This all seems to go wrong at the end. What on earth happened, or better yet did I mess up somewhere along the way? |
Let's go for something that you can get a fulminate with first. Why don't you try using mercury and adding a wee bit of silver to that? The reason I
offer this approach is that in that, you may find where the real problems lay......Mercury dissolves rapidly in HNO3 and provides a "carrier" for a
few other metals that will make energetic fulminates. PLUS it's much less sensitive. but if you don't have any Hg here is what I can offer at this
juncture.....
You see, fulminates are occasionally a "feel" project in chemistry. I know that sounds very unscientific but there are some things that can go wrong
with the reaction in terms of timing and contents.
I'll tell you RIGHT NOW that one of the biggest problems I have heard of in making fulminates are these:
1- YOU MUST USE REAL ETHYL ALCOHOL. Using anything but 190proof grain ethyl alcohol (the shit you drink!) will result in problems (inconsistent
results guaranteed).
2- The temp of the reactants should start at room temp and move up. Start at lower than 20C and you will have a delayed reaction that may "spike" too
quickly with the introduction of heated material.
3- When you make a nitrate suspended in acid - DON'T MIX IT. Let it stand as it dissolved. This is a unique issue that has little explanation other
than it was a standard in Germany during fulminate production and does seem to be quite valid. (My German is poor but I read about it in a wonderful
text written in 1911 from a factory over there).
Think it over....do ANY of these apply?
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ssdd
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Ahhh I see. When I was dissolving the silver I had it on a magnetic stirer. As you explained this could be the issue I encountered. Does anyone have
any ideas whats happening here, after taking a gander around I couldn't find much. I may try it with mercury.
Just a quick update:
I let the beaker with the Blue/White solution sit overnight. When I came into the lab the next day I found a layer of gray powder on the bottom and
the liquid was clear. I decanted off the extra liquid and filtered out the powder. It is drying right now and I'll know tommorow if it reacts at all.
There was perhaps a .1-.2 gram yeild of this.
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Axt
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| Quote: | Originally posted by ssdd
I let the beaker with the Blue/White solution sit overnight. When I came into the lab the next day I found a layer of gray powder on the bottom and
the liquid was clear. |
Are you using distilled water? if your using tap water you are likely precipitating say... silver chloride.
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ssdd
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Ok I attempted to set off the gray precipitate today. Yet again there was no result. It did not respond to impact or flame. When I burnt the filter
paper that it was on it turned a green/gray and did not turn to ash.
As it was pointed out using tap water could make an issue. My guess that this gray ppt was simply silver chloride or something similar. Stupid me...
never took tap water into consideration. For now I have given up on silver fulminate, there are just to many ways to mess it up.
Thanks for everyones help.
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gregxy
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As was mentioned earlier, your 3 M HNO3 is too weak. I used 70% d=1.42 nitric acid and it worked for me, I think 70% should be about 15 molar.
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ssdd
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When I had first tried the fulminate I used a 15.8 molar nitric acid. I ran into the issue of the silver not dissolving because the silver was
pasivating. If there is a way around this I would love to know for future reference.
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The_Davster
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How odd, I have never experianced such things. What form is your silver in? I usually use a chunk hacked off a 1oz ingot, this exposes fresh silver
to react , perhaps your silver has become passivated before adding to acid from H2S in the air?
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Magpie
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This may help:
http://www.sciencemadness.org/talk/viewthread.php?tid=2772&a...
The single most important condition for a successful synthesis is good mixing - Nicodem
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ssdd
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The silver was in a powder form. I think it may have been a silver alloy in that the nitric turned a lovely shade of green when the powder was added.
When I added the silver to the 3 molar acid all of it disolved with the liquid turning a light blue color. I'm not sure if this color diffrence means
anything...
any thoughts?
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not_important
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How was the silver shot labeled? What I've seen is generally 99.9+ % silver, but you can get alloys - I'veen both sterling which has copper and a
silver-nickel alloy.
Either one may cause problems when making fulminate, and it does sound as if you've copper in there.
The only passivation with silver that I have heard of is 1) electroplating a thin film of tin onto the silver, not likely for shot, and 2) if there is
chlorides in the solution in which case a layer of sliver chloride can be formed.
I've never had problems dissolving pure or sterling silver in clean nitric acid of any reasonable strength.
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Levi
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| Quote: | Originally posted by ssdd
When I burnt the filter paper that it was on it turned a green/gray and did not turn to ash.
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The comment about it turning green near burning filter paper sounds like CuCO<sub>3</sub>. NiCl<sub>2</sub> is green also but
it would have been that way even before you burned the paper.
Chemcrime does not entail death. Chemcrime is death.
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nitro-genes
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The fulminate reaction with silver seems pretty sensitive to impurities, more so than mercury at least ast that worked fine with me.
If alloyed silver is your only source, you could purify it by precipitating a small amount of silverchloride with NaCl, thoroughly washing it, and
then strongly heat it to yield pure metallic silver and chlorine gas. Silver is one of the few insoluble chlorides, so this should eliminate most of
the impurities.
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not_important
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| Quote: | Originally posted by nitro-genes...
If alloyed silver is your only source, you could purify it by precipitating a small amount of silverchloride with NaCl, thoroughly washing it, and
then strongly heat it to yield pure metallic silver and chlorine gas. Silver is one of the few insoluble chlorides, so this should eliminate most of
the impurities. |
Seeing as silver chloride has a listed boiling point of 1550 C, there may be some problems with this approach.
A classic method of converting AgCl to the metal is fusion with Na2CO3. There are others as well.
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nitro-genes
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Since most silverhalides spontaneously decompose under the influence of light I thought it might be easily reduced by adding charcoal or decomposed by
heating alone, but apparently this is not the case for the chloride. It's not considered to aid in combustion according to it's MSDS so directly
reducing it probably doesn't work either.
You could always use more classic approach, like dissolving the silverchloride in ammonia and adding some formaldehyde to reduce it to silver, maybe
vitamine C would work as well. After that you could directly wash the silverfilm of the inside of the glass beakerwith some nitric acid to yield a
very pure silver nitrate solution.
Just tried with ascorbic acid, adding a filtered solution of ascorbic acid derived from vitamin pills instantly reduces Ag+, moreover it doesn't form
a film on the glass like formaldehyde does but appears like a dark grey/blueish suspension which could be filtered off without much trouble. terribly
impractical for purifying large amounts but it suffices for small amounts. I might use the same procedure for purification to experiment with silver
azides and complexes thereoff, in which copper impurities are highly unwanted as well...
[Edited on by nitro-genes]
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nitro-genes
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Did the synthesis myself too, since I couldn't imagine why the reaction yielding silverfulminate would be sensitive to impurities, while with mercury
this isn't a serious issue at all. So I dissolved 0.2 grams of fairly impure silvernitrate in 2 ml of demineralised water, added 2 ml of 70% nitric
acid and 3 ml of denaturalized ethanol (methanol and pyridine impuritues) and kept temperature at around 60 deg C.
The moment the mixture became about 50 deg. the reaction began, evident by slight bubbling. At the bottom of the test tube some white clouding could
be seen at first and after 10 minutes or so white feathery aggregates of SF started to form. The final yield was much higher than on the photo, which
was taken after about 10 minutes.
After the reaction was complete, the acid was decanted and the SF dissolved in ammonia after which ascorbic acid was added to destroy the SF. I felt
no need to experiment with it due to it's sensitivty.
[Edited on by nitro-genes]
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ssdd
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| Quote: |
Just tried with ascorbic acid, adding a filtered solution of ascorbic acid derived from vitamin pills instantly reduces Ag+, moreover it doesn't form
a film on the glass like formaldehyde does but appears like a dark grey/blueish suspension which could be filtered off without much trouble.
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My main question to this would be: Are you reacting this with the silver alloy or the silver chloride you mentioned?
This is a obvious question, but how did you go about deriving the acid from the vitamin pills? This sounds like a good method that may actually work
for me... I'm also thinking my issue may have been with tap water. The iron content in my towns water is very high and the pipes at the school are
fairly old. So my guess would be that it could have given me some issues.
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