chief
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Dangerous Cu(x) (NO3)(y) ???
I dissolve about 300-400 gm of solder (hopefully with lots of silver in it), together with the Cu, that was soldered with it, in HNO3.
The reaction is going on in my backyard. Now I have read, a while ago and from different sources, that Copper-Nitrate is dangerously explosive !
Since the metal in the 500 ml-flask is a lot, maybe it forms crystals therin ...
Probably I'm gonna dilute it, before the conc.is too high, but:
Can it explode ? What can I do with the Cu(NO3)x - solution, after I got aout the silver ?
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DJF90
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Googling copper nitrate reveals that it is a fairly common lab reagent. There appears to be no hazards to note, other than the fact that it APPARENTLY
spontaneously ignites paper in the presence of moisture. Maybe I'm missing something but I think you are worrying too much about nothing.
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Jor
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No, it's not explosive. It is an oxidiser however, but it's very hygroscopic, so I doubt it can be used as a decent oxidiser.
Heating results in loss of NO2.
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The_Davster
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It's not.
The hydrated form you will produce from this reaction is complelty harmless in solution, as is the solid hydrate form which is difficult to obtain
because it is so deliquescent.
The anhydrous copper nitrate is the one which is a potent oxidizer, but it took forever for chemists to isolate it because it was so hygroscopic. It
used some sort of gas reaction IIRC, nothing that can happen using any trace of water.
I am not sure on the explosive nature, but it may just be a case of the MSDS horribly exagerating.
You have nothing to worry about.
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Jor
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I would not call copper solutions harmless. They are not really good for the heath, and AFAIK they are somewhat cumulative, although they have a much
shorter half life than lead. I have been to careless with copper solutions, and I handle them with much more care now. Im not scared about short term
exposure, but long term. I have this with all toxic metals, e.g. cobalt, chromium, mercury, nickel, lead and so on. Ofcourse copper is nothing in
comparison with mercury and lead, but still, not healthy.
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The_Davster
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Ok, you got me , I meant harmless in terms of what chief was worried about. I
agree it is toxic, but compared to the other metals you posted, it is one of the more benign.
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Magpie
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re: preparation of copper nitrate, The_Davster says:
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The hydrated form you will produce from this reaction is complelty harmless in solution, as is the solid hydrate form which is difficult to obtain
because it is so deliquescent.
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I have prepared cupric nitrate in solution, pH about 4, which I believe is about right for the neutral salt. I would like to end up with cupric
nitrate trihydrate, or perhaps more properly cupric nitrate hemipentahydrate.
My first effort was to just place the solution in an evaporating dish and let it set in the sun. I'm making no progress here. I understand that this
salt is deliquescent. My next thought was to place it in a drying oven at about 110C.
Do any of you have other advice? Thanks in advance for any suggestions.
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Klute
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I'm afraid you will form Nox vapors and mixed copper salts. I tried cristallizing it too, even adding acteone to a concentrated solution, nothign
worked, so i just keep the liquor as such, knwo the amount of copper nitrate present (made from copper wire and HNO3), and measure out the volume I
want when needed.
I think hydrated copper nitrate cna be sued as a mooth oxidant, I remember reading things about it being able to oxidize alcohols, and benzyl halides
to aldehydes, but never got enough tangible info to warrant working into it.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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Formatik
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I've placed an aqueous Cu(NO3)2 solution in greater volumes of either acetone, anhydrous ether, and MEK all into a freezer on the coldest setting for
a while. Copper nitrate is also well soluble in primary alcohols even at freezing temperatures. I did eventually get solid nitrate with MEK. With MEK
and ether, the nitrate froze into a clump IIRC. The clump removed and quickly broken up and was put in a larger amount of MEK, then this was gently
heated and stirred very well and part of it precipitated. I haven't tried to freeze the nitrate in aq solution itself and then added that to the MEK
to see if that also does it.
Copper nitrate is said to be insoluble in methyl acetate, and since this ester has an at least moderate solubility in water, an extraction using this
and a concentrated nitrate solution could work even better. Finding out what the industrial method of separation is used would be good to know.
[Edited on 14-10-2008 by Formatik]
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Magpie
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Thanks for your helpful replies. As suggested I did a little looking in the library to see what industrial or other methods were being used to make
anhydrous Cu(NO3)2. I couldn't find much information as it seems it is not a very important compound commercially. The few methods I did find used
N2O4 and non-aqueous conditions. One source said that it is sometimes sold as a brine of 14%Cu.
For me I think using the brine I have will be perfectly satisfactory. I should, however, assay the brine for Cu content. I made the brine from
homemade nitric acid (diluted) and pottery grade malachite [CuCO3*Cu(OH)2]. So not only did I start out with inexactly known materials but I ended up
trimming the final mix with bits of malachite and HNO3 to get the final pH of 4 and "no more fizzing."
[Edited on 15-10-2008 by Magpie]
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chloric1
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Humidity and temperature play huge roles in copper nitrate crystallization. I have a container of mostly wet nitrate I managed to solidify with a
heat lamp I believe. I did not lose nitric acid but I know the weather by my jar if copper nitrate 
Magpie, how do determine copper? Do make sample into Tollen's reagent and add standardized sugar? Or do you use potassium iodide with thiosulfate
back titration?
Fellow molecular manipulator
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Magpie
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| Quote: |
Or do you use potassium iodide with thiosulfate back titration?
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Yes, the above is what I plan to do. My rough calulations from makeup materials indicate I have roughly 3M, or 17%Cu.
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jarynth
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I understand copper nitrate is dangerous in the presence of ammonium ions, maybe that's what chief meant... correct me if I'm wrong.
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ssdd
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In the past I was making simple pyrotechnic mixes and found that adding copper nitrate (for color) often resulted in a spontaneous ignition of the
mix. The mix did contain ammonium perchlorate.
Later I tried making the same mix but without the copper and found it to be stable (as far as pyrotechnic mixes go).
So when it comes to this I guess it is safe to say just to be careful with what you mix it and read up on it before you try it.
-ssdd
All that glitters may not be gold, but at least it contains free electrons.
-- John Desmond Baernal
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chloric1
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copper is a combustion catalyst especially when perchlorates are involved.
Fellow molecular manipulator
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