budullewraagh
Hazard to Others
Posts: 168
Registered: 1-8-2004
Location: new york
Member Is Offline
Mood: Aliphatic
|
|
h2o2 extraction
i have a nice large bottle of 40% hydrogen peroxide. unfortunately it is white and viscous. the other ingredients (aside from water and hydrogen
peroxide) are: cetaryl alcohol, cetareth-20, stearic acid, cetyl alcohol and phosphoric acid. i froze the solution and the hydrogen peroxide
didn't come out. that's not cool at all. it was just a white solid. how can i extract the peroxide?
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
You've misunderstood.
"freezing out" is also known as fractional freezing.
To precipitate out the water, don't just freeze the whole mixture. That will always result in a solid mass.
First the water begins to freeze, then, soon after, the peroxide freezes too. You've got to grab it after stage one, but before stage two..Eh?
You've got to watch the process, at least intermittently, and maintain at least slow stirring while it happens so as not to have a temperature
gradient form.
Often a smaller griffin beaker is placed in griffin beaker with a cooling mixture (like crushed ice and salt).
Slow stirring is mantained and when a slurry forms the crystals are filtered out (with a cold filtering setup). And plunked into a clean beaker before
they remelt.
As you can imagine, it requires finesse, and a skillful technique before reliable and consistent results are achieved.
(easier said than done)
EDIT: oops!
[Edited on 23-10-2004 by Hermes_Trismegistus]
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
budullewraagh
Hazard to Others
Posts: 168
Registered: 1-8-2004
Location: new york
Member Is Offline
Mood: Aliphatic
|
|
what if the solution is cooled to 0 celcius and no lower? then surely the peroxide will not freeze, as its freezing point is -11 celcius
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
I think Hermes got it reversed, the water freezes first, at which point it can be removed, leaving liquid peroxide more concentrated than it was
before.
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
solutions freeze at different temperatures than the components.
anyway, I should have referred you here to begin with.
H2O2 overview
Concentration via Sparging
Fractional Freezing.
as for "what if's"..........feel free to experiment....and then report back to us about the results....
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
| Quote: | Originally posted by rogue chemist
I think Hermes got it reversed, |
at first...as concentration rises the situation first reaches equilibrium....then reverses....so it really depends on what concentration you're
starting with and how high you need to go....from what I've read (peculiar huh!)
But yes, I did. 
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
