Virus
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Amines in Acid/base extraction
I have few questions about acid/base extraction and amines but it seems nobody is able to answer them fully, I hope you here are.
I did A/B few times yet. Here are my questions to what I saw:
1) Methylamine was dissolved in pure water. After few NaOH additions there showed up something like white "powder" at the bottom of a beaker. Is it
methylamine freebase which I can see now because it is in its freebase form insoluble in water and hence it precipitates?
2) Is it possible to pull methylamine into toluene with NaOH? I reached pH 13 and there was nothing in toluene. Or at least not in water after
titration via HCl.
3) There are only two amines I was able to pull into non-polar solvent after basing with NaOH. Until recently it was easy at all. After proper pH was
reached, I could see some white mass rising up into non-polar even without shaking, within two minutes the water layer cleared up again and the yield
was near to 90%. But I was obliged to begin pulling the same amine from a solution of H3PO4, no white rising to the top can be seen from that time,
even if pH is about 14 the solution stays milky, shaking without any noticable effect, yield decreased to something about 20%. Why? BTW it was told me
that if Id perform basing slowly it could help a lot. Can this be a truth?
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Hilski
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Methylamine freebase is a gas.
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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bio2
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.......1) Methylamine was dissolved in pure water. After few NaOH additions there showed up something like white "powder" at the bottom of a beaker.
Is it methylamine freebase which I can see now because it is in its freebase form insoluble in water and hence it precipitates?................
It seems you have little or no understanding of what it is you are trying to do. Assuming you mean the hydrochloride salt above
the white solid would be salt, sodium chloride.
Try to understand the reactions and reagents involved before you begin mixing chemicals. Methylamine is a gas BTW.
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solo
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Here is a time held post by Mad Max from the Hive ....which will explain the logic .....solo
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MaDMAx
(Hive Addict)
03-22-02 12:19
No 286519
LOOK! Recrystallization and A/B general info
(Rated as: excellent) Reply
OK this is for the newbies of now and the future. So when someone asks a
question that is explained with this thread you can tell them they are
remiss in their finding skills and that should have found this thread by
using the fucking search engine (UTFSE). This thread will describe
crystallization of most drugs with an amine such as methamphetamine (meth)
and MDMA.
Definitions
solvent - A substance, usually a liquid, that dissolves something else
solute - A substance that is being dissolved in something else
solubility - How easily a substance dissolves in a certain solvent
acid - A substance that gives up a proton easily
base - A substance that accepts a proton easily
salt - The product from the reaction of an acid and a base
freebase - The natural form of a drug, hasn't been reacted with an acid.
You can change a drug back and forth between the freebase and the salt as
many times as you want.
Explanation of A/B (acid base) extraction
Most drugs have an amine group. This is a -NH2 attached to the molecule
somewhere. NH3 is a base (accepts protons from acids easily) so the drugs
are bases also. Hence the name freebase. When you make the drug, it
usually starts out in the freebase form, which is quite often an oil. What
happens when you react an acid and a base? You get a salt. So when you
take your freebase (base) drug and react it with an acid, you get a salt,
such as a hydrochloride salt if you react it with hydrogen chloride (HCl).
Salts are usually crystalline solids rather than oils or waxy solids,
which is why they are so popular with drugs, it makes them easier to
handle, and the drug properties are not changed. Think about it, you have
HCl in your stomach, and acid throughout your body, so if you ingest a
drug in either form, it will end up being in the same form (probably a
salt) in your body no matter how it started out.
Freebases and salts usually have drastically different properties. An
important one is that freebases are usually soluble (will dissolve in) in
non-polar solvents such as toluene and hot naphtha, and not soluble in
polar solvents such as water. The salts are usually the opposite, soluble
in water, but not toluene etc. This is how acid/base extractions (A/B)
work.
You can basify your molecule with NaOH (lye) to form the freebase, which
is not soluble in water, but it will dissolve in a non polar solvent. So
you add your non-polar solvent and the freebase goes in to it (a lot
faster if you shake it all up instead of waiting for the freebase to float
up to it). Once you have freebase in your non-polar you can wash the
non-polar solvent with water to get rid of any non-freebase drug material
(such as excess lye). The water will not remove any of your freebase.
Then to recover your hydrochloride salt (the most popular form of most
drugs), you react it with hydrochloric acid. Muriatic acid is hydrogen
chloride (HCl) dissolved in water. So if you add this to the non-polar
with the freebase, the freebase will react with the HCl to form the salt,
which is now soluble in water and not in non-polar, so it will dissolve
into the water layer, which you can separate and evaporate to obtain your
crystals.
Since evaporating water sucks, and quite often leaves behind impurities,
it is nice to react your freebase in non-polar with HCl without any water
around. This is when gassing comes into play. You can generate pure HCl
which is a gas without any water, and bubble this gas through your
freebase/non-polar. It will react with your freebase to form the
hydrochloride salt (what you want). Since the salt is not soluble in the
non-polar, it will them fall out of solution as crystals which can be
collected by filtering.
Explanation of recrystallization
Once you have your dry drug hydrochloride salt crystals, sometimes you
want to get them more pure, because impurities can be trapped inside the
tiny clumps of crystals. A good way of doing this is to recrystallize. The
idea behind this is to find a solvent that the crystals are kind of
soluble in and kind of not. Alcohols usually work well for this. When
talking about solvents and solid materials, hot solvent dissolves more
solid than cold solvent, so this can be used to your advantage. (The case
is opposite for gases but I won't go into that).
Get two containers. Put some alcohol in one and bring it up to boiling.
Put your crystals in the other container. Slowly add boiling alcohol to
your crystals and they will dissolve. Use just enough alcohol to dissolve
all of your crystals.
Now since cold alcohol doesn't dissolve crystals very well, cool down the
alcohol/product and the crystals will come back out (recrystallize). The
slower you cool the alcohol, the bigger the crystals are. The bigger the
crystals are, the fewer impurities will be trapped inside of them, and the
purer your product will be. So big crystals = pure crystals (usually).
One good way for ensuring that your alcohol cools down nice and slow is to
put some water in a pot and heat it to boiling and take it off of the
heat. Then put your container with hot alcohol/dissolved crystals in the
pot of water being sure not to get any water into the alcohol, cover the
container, and let it cool down to room temperature. Then you can put the
container with alcohol in the refridgerator to cool more. Then into the
freezer to cool more. Then you can filter your pretty crystals out. Now
there is usually still a little bit of product left in the alcohol, so if
you boil off say 75% of the alcohol and repeat the cooling process you can
get some more crystals.
There are other ways of changing the solubility of the crystals in the
alcohol, such as adding acetone or ether to the alcohol, but the
temperature method works quite well, is cheap, and simple. So newbies
should use it first, then experiment with other methods if they want to.
If you knew all of this already then good for you. If you didn't then I
hope I did a good enough job of describing these two concepts to chemistry
newbies. From now on, if someone asks a question about A/B extractions or
recrystallizations, or a myriad of other questions that can be answered by
this post, tell them they need to learn to UTFSE, then give them a link to
this post.
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Ozone
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On review of the evidence, this person simply has not made MeNH2. This is why his/her trials have yielded nothing.
Please try again,
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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Virus
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Im sorry, in point one and two I spoke about hexamine not methylamine. Can you answer again?
[Upravil dne 27-1-2007 Virus]
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badboy39560
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basify a molecule
Im attempt an A/B extraction. Never done it before. I was wondering when adding NaOH, how much do i need to make it freebase. Would i use the same
amount as the substance i want to make freebase? I understand the process, but i need to find out the amount of base i would need. Thanks.
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