bluetrain
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Separating KOH from hypochlorite mixture
The only product containing calcium hypochlorite (besides water-solutions) that i can purchase also contains KOH (~30%). How can i get rid of the KOH?
Is there any acid that won't react with the hypochlorite? Is there a solute which won't dissolve just one? I can't find much information on the net,
hope someone can help me out here.
Thanks.
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not_important
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Not really, unless the mixture consists of defferent physical forms, such as a fine powder and prills or flakes.
Calcium hypochlorite has a fairly low solubility in water, while that of KOH is high. But calcium hypochlorite solutions and damp calcium
hypochlorite are not particularly stable, while both calcium hypochlorite and potassium hydroxide release heat when mixed with water which hastens
the decomposition of the hypochlorite.
The lower alcohols dissolve KOH, but calcium hypochlorite strongly reacts with them (the 'chlorine bomb' of youtube fame) so they're not useful.
Boric acid will react with hypochlorites to form free hypochlorous acid, so it what you want is a KOH-free solution of hypochlorite and the borate
formed wasn't harmful you could add the proper amount of boric acid to react with the much stronger base KOH.
But why is the KOH a problem? If you are out to make chlorine, the KOH will waste acid but tech HCl is cheap. If you're making chloroform again the
KOH isn't a real problem, and the boric acid trick can help out.
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bluetrain
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Thanks. Think I have some boric acid left from making a photo developer, I'll give it a shot. I'm quite certain KOH would be a problem in my reaction
(not chloroform btw). Are you sure it won't work to dissolve in water if sufficient cooling is applied? Or what about making hypochlorite from Ca(OH)2
and Cl2, seems cheap and easy?
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kclo4
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Yeah, I don't know how cheap it would be to make Calcium Hypochlorite, but I'm sure you could make it by adding Chlorine to Calcium Hydroxide. If
Potassium Hypochlorite worked for you as well, you could just bubble chlorine into your mixture to turn the KOH into KOCl. This might be tricky since,
as mentioned earlier when KOH dissolves it produces a lot of heat and could destroy the chlorite.
The cheapest way to make chlorine is to use TCCA and HCl I believe, and It seems like you would want to plan for suck back, I don't know how fast it
reacts, but I'd assume that could be a big problem.
What is the reaction you plan to use with this Calcium Hypochlorite?
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bluetrain
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It will be used for oxidation of ethers and other future oxidation experiments (e.g. MnCl2 -> MnO2). Think I'll try dissolving in ice-water and
bubble chlorine into the mixture if the boric acid method fails. Thanks for your responses 
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12AX7
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Alcohol dissolves KOH, right?
LMAO...alcohol seperating KOH from a hypochlorite... what a fucked up idea! 
Tim
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kclo4
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No one had the idea of separating KOH from a hypochlorite with an alcohol. not_important just said why it wouldn't work.
| Quote: | | The lower alcohols dissolve KOH, but calcium hypochlorite strongly reacts with them (the 'chlorine bomb' of youtube fame) so they're not useful."
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What are you talking about 12AX7?
[Edited on 27-9-2008 by kclo4]
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not_important
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The KOH would be no problem for the Mn(II) to Mn(IV) oxidation, you even want added alkali to sop up the chloride from the MnCl2.
Slowly added ice water while cooling might work, some hypochlorite loss will occur through decomposition and solution, and you will need to use the
washed hypochlorire quite quickly.
Note that calcium borates are also sparingly soluble, however because it is a so much stronger base the KOH should react first, until the pH drops to
9.2 or so. Below that increasing amount of free HOCl will be formed.
An alternative those two would be to first slowly pass cold moist CO2 over the solid until enough CO2 has been absorbed to form K2CO3, then slowly add
ice water to dissolve that out; K2CO3 dissolves with less release of heat than KOH.
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12AX7
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| Quote: | Originally posted by kclo4
No one had the idea of separating KOH from a hypochlorite with an alcohol. not_important just said why it wouldn't work.
...
What are you talking about 12AX7?
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My fault for jumping into a thread without looking.
Tim
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