MrJoeyJiffy
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Alternative to HCL gas
I have always used an HCL gas generator to precipitate my salts from freebase solution although another member on another forum suggested another
method that seems much more preferable as HCL gassing is a mess and the clean up is no fun.
Extract freebase using xylene
drying xylene with drying agent(mgSO4)
combining equal parts of xylene/product with 99% IPA.
titrating IPA/xylene mixture to PH of 6 using 31% HCL solution
vacuum distill IPA off which should leave xylene and salt formed in flask
drying salt in a pyrex dish through evaporation then a little acetone at the end
I just wanted to verify before I try such method as it seems like a nice alternative to HCL gas.
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woelen
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First I want to make a remark about your use of symbols.
HCL --> HCl
PH --> pH
mgSO4 --> MgSO4
freebase --> most likely you mean free amine
Please be more precise in this. It makes your posts look much better and it helps getting a useful answer. Now your post looks like a failed attempt
of a cook.
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Now the answer to your question. I do not think that that 'another member on another forum' is a very good reference. First you put a lot of effort in
drying your xylene with the free amine dissolved in it and next, you add 31% HCl, with the rest being water! Does not sound very useful to me.
The IPA/xylene mix with 31% HCl most likely is going to be a nasty mess. It does not form a nice solution, but some goopy mass (xylene does not mix
with water and the IPA/xylene mix most likely partially dissolves and a lot of small droplets will mix with each other). Titrating to pH equal to 6
will be impossible with 31% HCl. One drop too much and your pH can suddenly go from e.g. 10 to 2 or so. The amine HCl salt may go into solution in the
aqueous layer and not precipitate out of the xylene layer.
The method presented here sounds too much like a cookery method to me.
[Edited on 13-9-12 by woelen]
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Rogeryermaw
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this does sound very much like cookery. sort of like reading steps out of a betty crocker cook book without a real understanding of the processes.
besides, if you know that an amine will dissolve in a non polar solvent and you salt it out with aqueous HCl, your salt will dissolve into the water
of solution. you would waste many hours waiting for xylene to evaporate to find that there was no "product" in it.
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MrJoeyJiffy
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Well I just got told.
Thanks for the information guys. I suppose my only other option is HCl gas into IPA.
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Nicodem
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Thread Moved
13-9-2012 at 06:41 |
MrJoeyJiffy
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After further reading(finally finding the original thread by Spice that I was looking for) I left out a key step and that is distilling the xylene off
of the freebase after it has been dried(Step2)
All steps after that meant to be interpreted as freebase instead of xylene, which would make a lot more sense because adding HCl solution to something
I just dried seemed to counter-intuitive to me as well.
Also after vacuuming(or evaporating) the IPA off you should be left with mostly salt that needs to be cleaned with acetone. Not xylene/salt like I
said in the first post.
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zoombafu
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The only way (that I know of) to precipitate a salt with HCl is to bubble the solution with HCl. It's really not that dangerous/difficult if you do
it correctly, and if you are worried about gassing yourself out or someting, do it outside. Also, making HBr salts is a bit scarier.
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hyfalcon
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Just vent the HCl through a basic solution to neutralize it after it's done what needs to be done.
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liquidlightning
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This is indeed cookery. Cross posted to a cookery forum. Lol.
Anyway HCl gas is still going to be the easiest method.
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