xfusion44
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Best way to separate tetraamine copper sulfate and ammonium sulfate?
Hi!
I've made some tetraamine copper sulfate (solution was clear and nice deep blue color after filtration of copper hydroxide). I tried to get rid of
water by heating the solution on a hot plate - and that worked until it started foaming too much. Solution also became light blue (there was no more
purple color to it). On the bottom of the beaker I've noticed some purple precipitate and also something white-ish (I think that's probably ammonium
sulfate). There was also something greenish (maybe copper hydroxide? - but is it soluble enough?). However, I've used ethanol to force the remaining
tetraamine copper sulfate out of the water and after filtering, the water is almost clear (only a bit blue) and on the filtering paper there's a lot
of blue precipitate, but only a small amount of purple precipitate - is it possible that tetraamine copper sulfate and ammonium sulfate are somehow
mixed, to give this blue color? And how to separate them?
Thanks!
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zed
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Seems like I've done something similar, in the distant past.
My advisor, at the time, instructed us to not let the material completely dry out.
Could present an explosion hazard. Recalling the peril presented by Silver Ammonium Nitrate, it seems possible.
Somewhere out there, in a book, is the procedure I used. I'll try to cruise the NET to find it.
[Edited on 5-1-2017 by zed]
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DraconicAcid
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There is absolutely no danger of explosions from tetramminecopper(II) sulphate.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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zed
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Yup! Explosions not a problem. Chemsnake makes the material on Youtube, then reports that it was not possible to detonate it.
Tetraamine Copper Nitrate, on the other hand, is a different story. https://www.youtube.com/watch?v=YaCLTWsHEpI
Methinks I should revisit my advisor's book, we did some very nifty experiments.
[Edited on 5-1-2017 by zed]
[Edited on 5-1-2017 by zed]
[Edited on 5-1-2017 by zed]
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pantone159
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I suspect that you drove the ammonia away as a gas. You should not have had any copper hydroxide left, if you did, you did not use enough/strong
enough ammonia. The wikipedia page for this compound suggests to add alcohol to precipitate the purple complex.
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xfusion44
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Thank you all!
@pantone159
Yes, that's exactly what I did - I didn't use enough ammonia and I also didn't use enough ethanol to precipitate the tetraamine copper sulfate.
Here are some pictures 
Those white crystals on the last six pictures are probably ammonium sulfate - they look nice, but how to get them out of purple complex?
[Edited on 5-1-2017 by xfusion44]
    
[Edited on 5-1-2017 by xfusion44]
 
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