First I would like to say, I am impressed for your anticipation of possible toxic gases from known impurities that may reside in your zinc source.
Definitely, perform this reaction in a well vented setting.
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There is a known electrochemical reaction in the presence of acid (H+) and oxygen (O2) with a metal in a lower valence state producing a basic salt.
Some examples:
4 Cu(l)/Fe(ll)/Co(ll)...+ O2 + 2 H+ --> 4 Cu(ll)/Fe(lll)/Co(lll) + 2 OH- (see, for example, http://www.sciencemadness.org/talk/viewthread.php?tid=81800#... )
Add NaCl (good electrolyte as this is an electrochemical reaction) and also H2O2 (or pump in O2 or boil in air) to create the basic salt.
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Alternatively, with respect to your preparation, you can actually make hypochlorous acid , HOCl, and then directly react it with zinc oxide (see
Mellor reference, https://books.google.com/books?id=8w1GAQAAMAAJ&pg=PA274&... ). To quote:
“As with magnesium hypochlorite, A. J. Balard likewise form a soln. of zinc hypochlorite by the action of hypochlorous acid on zinc oxide. T soln.
behaved in an analogous manner when the attempt was made to concentri it invacuo. A. J. Balard also prepared a similar soln. by double decomposition
zinc sulphate and an excess of calcium hypochlorite. G. Lunge and L. Land obtained a soln. of zinc hypochlorite by a process similar to that employed
P. Grouvelle. They found that some chlorate was formed when working at 1 and still more at higher temp. The zinc hypochlorite was found to decompo
into zinc chloride or oxychloride and oxygen. “
The preparation of ZnO (or it could be the oxychloride employing HOCl and not NaOCl) in good supply can be achieved by a galvanic corrosion reaction
(see my related thread at http://www.sciencemadness.org/talk/viewthread.php?tid=84047#... ). This is a simple electrosynthesis using a microwave to jump start the reaction.
Just place Zn metal in a jar with aqueous chlorine bleach, NaOCl (or perhaps here try HOCl, note, I can’t remember if dilute H2O2 works to a limited
degree in place of NaOCl or HOCl), some NaCl (better perhaps is sea salt) and a carbon source (a graphite rod from a pencil of say 1 ½ inches should
work and is a very noble) or use noble metals like a silver plated coin, or a US quarter (Nickel-Copper alloy), but I don’t like the idea of any
possible toxic nickel ions getting into the brew.
I'll give you a link to my recommended path for making hypochlorous acid using aqueous NaOCl, plus dry NaHCO3 and dry CaCl2 (see http://www.sciencemadness.org/talk/viewthread.php?tid=76591#... ). However, you may wish to try the simple impure route of mixing chlorine bleach
(NaOCl) with 5% vinegar in the appropriate proportions (or excess of NaOCl) to produce HOCl and sodium acetate (no excess vinegar). Normally the
acetate may be an issue, but in the presence of zinc oxychloride, I'm not sure if you would even get a reaction in cold solutions, so perhaps you can
just separate out the unreacted zinc oxychloride salt that is formed with the decomposition of unstable Zn(OCl)2.
The additional benefit of this path with HOCl acting on any unreacted impure Zn, is that I'm pretty sure, for example, that if you react a sulfide
with Hypochlorous acid or Chlorine Bleach (NaOCl), you would not get Hydrogen sulfide (a toxic gas also), but instead just a suspension of fine
sulfur.
HOCl --> HCl + O (partial decomposition reaction)
2 HCl + ZnS --> ZnCl2 + H2S
HOCl (or NaOCl) + H2S --> H2O + S + HCl (or NaCl)
[Edited on 4-12-2018 by AJKOER] |
