AJKOER
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Conc HOCl / HClO3 Preparation
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]
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Traveller
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Quote: Originally posted by AJKOER  | 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] |
I was quite surprised when I looked at the link you posted
http://www.clorox.com/products/clorox-regular-bleach/ingredi...
at how little sodium hydroxide was in Clorox bleach. The ph of bleach is over 12, yet NaOH is the 2nd smallest ingredient; just slightly more than
sodium polyacrylate.
Any idea just how much NaOH would be in a litre of 6% Clorox bleach?
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AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
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I would expect the decomposition of isolated hypochlorous acid solutions to yield different products depending on the reaction conditions. In dilute
aqueous solution, and especially when heated, I am sure it would disproportionate into chloric acid and chlorine. However, I suspect that under other
conditions chlorine dioxide may form.
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AJKOER
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| Quote: Originally posted by AndersHoveland | | I would expect the decomposition of isolated hypochlorous acid solutions to yield different products depending on the reaction conditions. In dilute
aqueous solution, and especially when heated, I am sure it would disproportionate into chloric acid and chlorine. However, I suspect that under other
conditions chlorine dioxide may form. |
Actually there is support for the formation of ClO2 in the cited reference to World Patent W091-03421-1 (titled “High Purity Chloric Acid” link http://www.google.com/patents/EP0490978A1?cl=en ) based on the reaction using 20% HOCl, which is a somewhat concentrated condition for
Hypochlorous acid:
5 HOCl --> 2 Cl2 + 2 H2O + HClO3
as on reading the Patent, I believe the HClO3 yield was increased by performing the reaction in a sealed chamber versus open (which may indeed imply
that ClO2 was formed and escaped reducing Chloric acid yield). However, under sealed conditions, are not each of these two equilibrium reactions
moved to the right due to pressure considerations?
Cl2 (g) + H2O <---> HOCl + HCl
2 ClO2 (g) + H2O <--> HClO2 + HClO3
and:
HClO2 + HOCl <--> HClO3 + HCl
[Edited on 4-2-2013 by AJKOER]
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AJKOER
Radically Dubious
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As Chlorine Bleach consists of the top three alkaline ingredients NaOCl, Na2CO3 and NaOH (the NaCl is about neutral), I am not completely surprised
on the high pH. If one starts with NaOH in water and adds a little HOCl and a lot of CO2 (which is NOT the way Bleach is actually made of course), I
would expect a high pH.
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