• N&PD Moderators: Skorpio

Extracting Amines for Dummies

nuke

Bluelighter
Joined
Nov 7, 2004
Messages
4,190
Materials needed:

Hardware
Separatory funnel (500ml-1000ml)
Compressed air/aerator with metal or glass tube at end
Vacuum filtration flask
Buchner funnel
Funnel seal
Funnel filters
Water aspirator/hand operated vacuum pump
Glass flask (500ml)
Glass stir rod
Chemical spatula
Watch glass or other flat/glass container
1 liter plastic container
4 liter plastic container (if from plant sources)
Glass funnel (and glass beakers to filter into if you want to make things easier)
Funnel filter paper
Wash bottle (for DH2O -- it'll make your life easier)
Litmus paper

Chemicals
Hydrochloric acid ("muriatic acid") or sulfuric acid (our acid)
Sodium hydroxide (our base)
Diethyl ether (non-polar solvent)
Distilled H2O (polar solvent)
Sodium chloride ("table salt", non-iodized)
Magnesium sulfate ("epsom salts")

*** Ghetto chemical substitute for diethyl ether ***

Premium starting fluid may be used instead.* It
contains around 60% ether and the rest is small-
medium chain hydrocarbons (mostly heptane and
hexane). Be sure to wash the starting fluid with
distilled H2O several times first (put it in a
separatory funnel with DH2O and shake lots, remove
the aqueous layer, repeat). After you're done
washing to remove impurities, add dry MgSO4 until the
non-polar layer is dry (the MgSO4 will stop clumping
and swirl around freely when shaken, like sand).

Gravity filter this, discard the used MgSO4 and
filter and put your non-polar solvent in a container.

One question which is sure to come up is: Why not
naphtha? The reasoning is that naphtha contains a
whole lot of carcinogens, is poor in purity and
dissolves most amines less effectively than diethyl
ether (forcing you to use more of it!). This technique
also doesn't require the drying of naphtha, which
requires a fume hood, or at least it should.

*As I've been told, the easiest way to procure the
solvent from the can is to turn it upsidedown, spray
to remove all the aerosol, then flip it right side up,
puncture the top and pour the solvent out. I've
only ever used lab grade ether so I can't attest to
the safety or efficacy of this method!

ALWAYS WEAR SAFETY GLASSES! SODIUM HYDROXIDE CAN
EASILY CAUSE BLINDNESS IF IT GETS IN YOUR EYES!


Preparatory work
-Preparing a 1 pH / 0.1 M (molarity) acid solution
Using the formula V1C1 = V2C2 and some algebra:
x mL * y M = 500ml * 0.1M
Where we want a solution of volume 500mL and
molarity 0.1. So, if we have a 10% HCl acid solution
(2.87 M solution) we solve as follows:
x mL = [(500ml * 0.1M) / 2.87M]
x mL = ~17.42 mL
Now that we have the numbers, we measure out
~18mL of our 10% solution, slowly add it to ~480
mL distilled H2O, and then our solution is prepared!

ALWAYS ADD CONCENTRATED ACID TO WATER
TO DILUTE! NEVER VICE VERSA.


%/M conversion tables can be found here:
http://en.wikipedia.org/wiki/Hydrochloric_acid

-Preparing the 3M (molarity) NaOH solution
Take a container (not glass; bases attack glass!) and
add 500ml distilled H2O. Add 120 grams NaOH
slowly, a gram or two a time, stirring as you do so.
Transfer this to your one liter container when it's
all dissolved, filling up to one liter.

-Folding funnel filters
http://jchemed.chem.wisc.edu/JCESof...ion/gravfilt_menu/FiltrationGravity2/MENU.HTM

-Setting up a vacuum filter
http://www.ic.sunysb.edu/Class/che133/techniques/suctfilt/suctfilt.html

http://www.wonderhowto.com/how-to/v...acuum-filtration-in-the-chemistry-lab-269380/

-Gravity filtration technique
http://www.wonderhowto.com/how-to/v...avity-filtration-in-the-chemistry-lab-269379/

-How to wash your glassware
http://www.wonderhowto.com/how-to/v...lass-apparatuses-in-the-chemistry-lab-269386/

-Making brine
Heat distilled water and add NaCl. Stir until it dissolves, and then continue adding NaCl until the solution seems to be saturated (precipitate at the bottom). Allow the solution to return to room temperature, put it in a container and throw it somewhere cool.

-Drying MgSO4
Put your MgSO4 in the oven on some aluminum foil, spreading out evenly, never more than 1/2cm high. Cook on 400F/200C for 60 minutes.

-Prepping your material
(starting from plant material): Add your powdered plant material in the 4-liter container. Fill with enough H2O so that your powder soaks, gets wet and becomes the consistency of a liquid. Now, basify with NaOH until you reach a pH of about 11 (depending on the pKb of your amine; less or more may be required, pH 11 works for most amines). Use litmus paper to test the pH. Continue stirring/shaking this material, then set aside for an hour or two.

(starting from impure mixtures or pills): The situation is similar; use a smaller container and follow the above steps. If you have an impure mixture, you should be able to see most of the amine dissolve.

-Using a separatory funnel
http://orgchem.colorado.edu/hndbksupport/ext/extprocedure.html

Background:
Amines are nitrogens with 3 bonds and at least one carbon bond. A primary or 1° amine is indicated by one carbon and two hydrogen bonds (R-NH2). A secondary/2° amine has two carbon bonds and one hydrogen, and a tertiary/3° amine has all carbon bonds.
Amines are mostly only soluble in non-polar solvents; however, if we were to protonate the amine (add a hydrogen), we would get a polar compound.

R-NH2 + H3O(+) -> R-NH3 (+) + H2O
(non-polar) + (polar) -> (polar) + (polar)

Hydronium (H3O) is the cationic product of the solvation of an acid in water. It tends to want to give away its extra proton to attain a neutral charge (H2O).

The reverse can also be completed:
R-NH3(+) + OH(-) -> R-NH2 + H2O
(polar) + (polar) -> (non-polar) + (polar)

Hydroxide (OH) is the anionic product of solvation of a base in water. It tends to want to take protons to attain a neutral charge.

This works for 1°, 2° or 3° amines.

For this procedure, you will need an amine that is a solid at room temperature as a freebase (this excludes things such as amphetamine, which is a liquid free base at room temperature).

Procedure:
1.) Add about 200ml of your non-polar solvent to your container with your material (it might be a good idea to check and see if your non-polar solvent dissolves your container first; this would be a problem). Agitate lots, let it sit awhile, then agitate more, repeating for a half an hour to an hour.
2.) Pour mostly your non-polar layer into the separatory funnel. Remove the rest of the aqueous layer (which, if you used ether, is on the bottom). Wash this layer a few times with brine (add brine, shake shake shake, separate).
3.) Pour the non-polar layer into your flask. Add dry MgSO4 until the non-polar layer is dry (the MgSO4 will stop clumping and swirl around freely when shaken, like sand). Rinse the flask and set it aside to dry.
4.) Gravity filter the non-polar layer. Discard the filter and MgSO4.
5.) Pour the non-polar layer into your separatory funnel.
6.) Pour in about 50ml of your acid solution. Shake the separatory funnel vigorously for about 5 minutes, then let the layers settle and separate the aqueous layer into your flask. Repeat until you use 200mL of the acid solution (4 washes total). At this point, remove the non-polar layer, dry it and put it in a container (it can be reused).
7.) Basify this solution until you reach a pH of about 11. At this point, depending on the amine, it may begin to form precipitate.
8.) Submerse your flask in an ice bath (ice and water!). The amine will precipitate out of the solution. Sometimes it can take quite a while, so be patient, continuing to add ice if it melts in the ice bath. *
9.) Once the precipitate is well formed, vacuum filter it. It's best to try to pour it in quickly, but if your filter is small you may have to do it in steps. Use brine or distilled water to get any residual precipitate off the sides of the flask, following by pouring it into the vacuum filter, or (painstaking but gets better yields!) use your spatula.
10.) Rinse the precipitate a couple times with brine and then once or twice with ice-cold water (some amines are slightly soluble in water, so you'll want to keep the water washing minimal and the water cold).
11.) When the precipitate appears dry in the Buchner funnel (5-15 minutes usually), remove the funnel, tap the filter paper and precipitate into the watch glass/flat glass container, scrape out any solid that's still left in the filter, and then leave it all out to dry overnight.
12.) Scrape the filter gently and discard it the next day. The solid should be very pure amine freebase!

* If the precipitate is forming poorly or the solution is cloudy, bubble air through it via your air tank/aerator for 1 to 3 minutes to remove any left over trace non-polar solvent which might still be in the solution. If you still are having problems, add a little brine to the solution to make it more polar.
 
Last edited:
And a pleasant warning:
THE ISOLATION OF SCHEDULE I DRUGS MAY RESULT IN PRISON OR JAIL SENTENCES SPANNING YEARS OR DECADES. BEFORE YOU APPLY THIS PROCEDURE TO ANY SUCH MATERIALS, PLEASE CONSIDER YOURSELF, YOUR FAMILY AND YOUR FRIENDS WHO MAY BE NEGATIVELY EFFECTED BY SUCH ACTIONS.

Also, some limitations of this procedure as reported by wikipedia:
-Zwitterions with acidic and basic functional groups in the same molecule, e.g. glycine which tend to be water soluble at most pH.
-Very lipophilic amines that do not easily dissolve in the aqueous phase in their charged form, e.g. triphenylamine and trihexylamine.
-Lower amines like ammonia, methylamine, or triethanolamine which are miscible or significantly soluble in water at most pH.

This is a general, common lab procedure and I don't know which amines it will apply to and work for (aside from the few aryl/alkylamines amines I've used it for, which were not psychoactive drugs). That's for you to determine!
 
Last edited:
The mnemonic for dilution is A&W, Acid into Water.
Water into acid will make it splatter and explode up on you.
 
Last edited by a moderator:
The mnemonic for dilution is A&W, Acid into Water.
Water into acid will make it splatter and explode up on you.

Well, that's a major error. It's fixed now, originally it was the reverse but then I changed it -- I was thinking for the preparation of metal ions and then got confused. Hopefully no one has been hospitalized in the 5 minutes it was up. ;)

Chemists: Double check the rest and let me know if I made any other mistakes.
 
Last edited:
Another point is to not work around any open flames or sources of high amounts of heat while working with ether because it is extremely flammable (autoignition temperature = 182 °C). It also tends to form explosive peroxides when exposed to air for extended periods of time (resulting in things like explosions about opening containers of ethers). Peroxides and water can be further removed by pouring the ether through activated alumina before storing. In the interest of safety ether which does not contain antioxidants should be discarded within 1-2 weeks after its initial use.

How not to kill yourself with ether (erowid):
http://www.erowid.org/chemicals/ether/ether_info2.shtml
 
Last edited:
Top