One possible path to concentrated Hypochlorous acid / Chloric acid acid and Chlorate salts without extensive distillation of dilute HOCl (distill half
and repeat as most of the volatile HOCl and Cl2O gas apparently passes over first) is as follows:
1. Prepare Lead Acetate, Pb(CH3COO)2, by slowing dissolving Pb (made more reactive by adding molten Pb to water) in Acetic acid/H2O2. Per Wikipedia
(http://en.wikipedia.org/wiki/Lead(II)_acetate ) to quote:
"An aqueous solution of lead(II) acetate is the byproduct of the 50/50 mixture of hydrogen peroxide and white vinegar used in the cleaning and
maintenance of stainless steel firearm suppressors (silencers) and compensators. The solution is agitated by the bubbling action of the hydrogen
peroxide, and the main reaction is the dissolution of lead deposits within the suppressor by the acetic acid, which forms lead acetate. Because of its
high toxicity, this chemical solution must be appropriately disposed by a chemical processing facility or hazardous materials center."
I remember the mention that air bubbles can replace the use of H2O2.
2. Add Bleach (NaOCl/NaCl/Na2CO3/NaOH see http://www.clorox.com/products/clorox-regular-bleach/ingredi... ) to vinegar and let stand. Then, add the Lead acetate forming precipitates of
Pb(ClO)2 and PbCl2 . Reactions:
Pb(CH3COO)2 (aq) + 2 HOCl --> Pb(ClO)2 (s) + 2 CH3COOH (aq)
Pb(CH3COO)2 (aq) + 2 NaCl --> PbCl2 (s) + 2 NaCH3COO (aq)
Reference: http://bcs.whfreeman.com/WebPub/Chemistry/ichem5e/Videos/Hyp...
3. Quickly decant (no heating as Lead hypochlorite is unstable and will eventually decompose at RT). Dilute and rinse with cold distilled water (best
if recently boiled to remove any CO2).
4. Add a dry weak acid (example Tartaric acid) to a small amount of solution containing water, Pb(ClO)2 and PbCl2 to create a strong solution of HOCl
and unreacted PbCl2 (with the Tartaric acid) and Lead Tartrate. Separate out the Lead salts to recycle Pb.
C4H6O6 + Pb(ClO)2 (s) --> PbC4H4O6 (s) + 2 HOCl
5. Warm the solution (between 30 to 70 C) for 2 hours. Depending on targeted Chlorate salt either add Lead basic carbonate (PbCO3·2Pb(OH)2 to prepare
the soluble Pb(ClO3), or K2CO3 (for KClO3), or Na2CO3 (for NaClO3), etc.
Expected reaction:
3 HOCl --> 2 HCl + HClO3
but more likely (see World Patent W091-03421-1 titled “High Purity Chloric Acid” link http://www.google.com/patents/EP0490978A1?cl=en ):
5 HOCl --> 2 Cl2 + 2 H2O + HClO3
where the added HOCl is driving the reaction to the right by reacting with the HCl. I would speculate that adding Basic lead carbonate may also work
forming Lead chlorate and an insoluble PbCl2. However, in the presence of conc HCl, it is possible PbCl2 will form a soluble complex (like PbCl3-)
voiding the benefit of using Basic lead carbonate.
To prepare Potassium chlorate, add Potassium carbonate and similarly for other chlorates:
K2CO3 + 2 HClO3 --> 2 KClO3 + H2O + CO2
References: See http://www.sciencemadness.org/talk/viewthread.php?tid=19477
The inspiration is from thread and the noted observation that Pb(ClO)2 when exposed to H2S (a weak acid) ignites the H2S. This to me implies that a
weak acid acting on Lead hypochlorite forms concentrated HOCl. The conc Hypochlorous acid either then releases Cl2O that ignites the H2S, or rapidly
disproportionates into HClO3 and/or Lead Chlorate that ignites the H2S.
[Edited on 2-2-2013 by AJKOER] |
